2012 Microchip Technology Inc. DS30575A-page 1
PIC18F97J94 FAMILY
Extreme Low-Power Features:
• Multiple Power Management Options for Extreme
Power Reduction:
-VBAT allows for lowest power consumption on
back-up battery (with or without RTCC)
- Deep Sleep allows near total power-down with the
ability to wake-up on external triggers
- Sleep and Idle modes selectively shut down
peripherals and/or core for substantial power
reduction and fast wake-up
• Alternate Clock modes Allow On-the-Fly Switching to
a Lower Clock Speed for Selective Power Reduction
• Extreme Low-Power Current Consumption for
Deep Sleep:
- WDT: 650 nA @ 2V typical
- RTCC: 650 nA @ 32 kHz, 2V typical
- Deep Sleep current, 80 nA typical
Universal Serial Bus Features:
• USB V2.0 Compliant
• Low Speed (1.5 Mb/s) and Full Speed (12 Mb/s)
• Supports Control, Interrupt, Isochronous and Bulk
Transfers
• Supports up to 32 Endpoints (16 bidirectional)
• USB module can use Any RAM Location on the
Device as USB Endpoint Buffers
• On-Chip USB Transceiver
Peripheral Features:
• LCD Display Controller:
- Up to 60 segments by 8 commons
- Internal charge pump and low-power, internal
resistor biasing
- Operation in Sleep mode
• Up to Four External Interrupt Sources
• Peripheral Pin Select Lite (PPS-Lite):
- Allows independent I/O mapping of many
peripherals
• Four 16-Bit Timers/Counters with Prescaler:
- Can be paired as 32-bit timers/counters
• Seven Capture/Compare/PWM (CCP) modules
• Three Enhanced Capture/Compare/PWM (ECCP)
modules:
- One, two or four PWM outputs
- Selectable polarity
- Programmable dead time
- Auto-shutdown and auto-restart
- Pulse steering control
Peripheral Features (continued):
• Hardware Real-Time Clock/Calendar (RTCC):
- Runs in Deep Sleep and VBAT modes
• Two Master Synchronous Serial Ports (MSSP)
modules Featuring:
- 3-Wire/4-Wire SPI (all 4 modes)
- SPI Direct Memory Access (DMA) channel
w/1024 byte count
-Two I
2C™ modules Support Multi-Master/Slave
mode and 7-Bit/10-Bit Addressing
• Four Enhanced Addressable USART modules:
- Support RS-485, RS-232 and LIN/J2602
- On-chip hardware encoder/decoder for IrDA®
- Auto-wake-up on Auto-Baud Detect
• Digital Signal Modulator Provides On-Chip OOK,
FSK and PSK Modulation for a Digital Signal Stream
• High-Current Sink/Source 18 mA/18 mA on all Digital I/O
• Configurable Open-Drain Outputs on ECCP/CCP/
USART/MSSP
• Extended Microcontroller mode Using 12, 16 or
20-Bit Addressing mode
Analog Features:
• 10/12-Bit, 24-Channel Analog-to-Digital (A/D)
Converter:
- Conversion rate of 500 ksps (10-bit),
200 kbps (12-bit)
- Conversion available during Sleep and Idle
• Three Rail-to-Rail Enhanced Analog Comparators
with Programmable Input/Output Configuration
• On-Chip Programmable Voltage Reference
• Charge Time Measurement Unit (CTMU):
- Used for capacitive touch sensing, up to
24 channels
- Time measurement down to 1 ns resolution
- CTMU temperature sensing
8-Bit LCD Flash Microcontroller with USB and XLP Technology
PIC18F97J94 FAMILY
DS30575A-page 2 2012 Microchip Technology Inc.
High-Performance CPU:
• High-Precision PLL for USB
• Two External Clock modes, Up to 64 MHz (16 MIPS)
• Internal 31 kHz Oscillator
• High-Precision Internal Oscillator with Clock
Recovery from SOSC to Achieve 0.15% Precision,
31 kHz to 8 MHz or 64 MHz w/PLL,
±.15% Typical, ±1.5% Max.
• Secondary Oscillator using Timer1 @ 32 kHz
• C Compiler Optimized Instruction Set Architecture
• Two Address Generation Units for Separate Read
and Write Addressing of Data Memory
Special Microcontroller Features:
• Operating Voltage Range of 2.0V to 3.6V
• Two On-Chip Voltage Regulators (1.8V and 1.2V) for
Regular and Extreme Low-Power Operation
• 20,000 Erase/Write Cycle Endurance Flash Program
Memory, Typical
• Flash Data Retention: 10 Years Minimum
• Self-Programmable under Software Control
• Two Configurable Reference Clock Outputs
(REFO1 and REFO2)
• In-Circuit Serial Programming™ (ICSP™)
• Fail-Safe Clock Monitor Operation:
- Detects clock failure and switches to on-chip,
low-power RC oscillator
• Power-on Reset (POR), Power-up Timer (PWRT)
and Oscillator Start-up Timer (OST)
• Brown-out Reset (BOR) with Operation Below VBOR,
with Regulator Enabled
• High/Low-Voltage Detect (HLVD)
• Flexible Watchdog Timer (WDT) with its Own
RC Oscillator for Reliable Operation
• Standard and Ultra Low-Power Watchdog Timers
(WDT) for Reliable Operation in Standard and Deep
Sleep modes
Device
Pins
Memory Remappable Peripherals
I2C™
10/12-Bit A/D
(ch)
CTMU
LCD (pixels)
USB
Deep Sleep w/VBAT
PPS (Lite)
Flash
Program
(bytes)
Data SRAM
(bytes)
Timers
8-Bit/16-Bit
USART w/IrDA®
SPI w/ DMA
Comparators
CCP/ECCP
PIC18F97J94 100 128K 4K 4 4 2 3 Y 2 24 Y 480 Y Y Lite
PIC18F87J94 80 128K 4K 4 4 2 3 Y 2 24 Y 352 Y Y Lite
PIC18F67J94 64 128K 4K 4 4 2 3 Y 2 16 Y 224 Y Y Lite
PIC18F96J99 100 96K 4K 4 4 2 3 Y 2 24 Y 480 Y Y Lite
PIC18F86J99 80 96K 4K 4 4 2 3 Y 2 24 Y 352 Y Y Lite
PIC18F66J99 64 96K 4K 4 4 2 3 Y 2 16 Y 224 Y Y Lite
PIC18F96J94 100 64K 4K 4 4 2 3 Y 2 24 Y 480 Y Y Lite
PIC18F86J94 80 64K 4K 4 4 2 3 Y 2 24 Y 352 Y Y Lite
PIC18F66J94 64 64K 4K 4 4 2 3 Y 2 16 Y 224 Y Y Lite
PIC18F95J94 100 32K 4K 4 4 2 3 Y 2 24 Y 480 Y Y Lite
PIC18F85J94 80 32K 4K 4 4 2 3 Y 2 24 Y 352 Y Y Lite
PIC18F65J94 64 32K 4K 4 4 2 3 Y 2 16 Y 224 Y Y Lite
2012 Microchip Technology Inc. DS30575A-page 3
PIC18F97J94 FAMILY
Pin Diagrams
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
48
47
22
44
24
25
26
27
28
29
30
31
32
PIC18F67J94 (128K)
1
46
45
23
43
42
41
40
39
V
SS
V
DD
AV
DD
V
DD
V
BAT
V
CAP
V
SS
V
SS
V
SS
V
DD
63
62
61
59
60
58
57
56
54
55
53
52
51
49
50
38
37
34
36
35
33
17
19
20
21
18
AV
SS
64
Note: Pinouts are subject to change.
64-Pin TQFP, QFN
MCLR CTED5/PGC/RB6
LCDBIAS2/RP29/WR/RE1
LCDBIAS1/RP28/RD/RE0
COM4/SEG28/AN8/RP46/RG0
COM5/SEG29/AN19/RP39/RG1
COM6/SEG30/AN18/C3INA/RP42/RG2
COM7/SEG31/AN17/C3INB/RP43/RG3
SEG26/AN16/C3INC/RP44/RTCC/RG4
SEG25/AN5/RP38/RF7
SEG24/AN11/C1INA/RP40/RF6
SEG23/CVREF/AN10/C1INB/RP35/RF5
D+/RF4
D-/RF3
SEG20/AN7/CTMUI/C2INB/RP36/RF2
VREF+/AN3/RP3/RA3
SEG21/VREF-/AN2/RP2/RA2
SEG18/AN1/RP1/RA1
SEG19/AN0/AN1-/RP0/RA0
SEG15/AN4/LVDIN/C1INA/C2INA/C3INA/RP5/RA5
SEG14/AN6/RP4/RA4
SOSCI/RC1
SOSCO/SCLKI/PWRLCLK/RC0
SEG27/RP18/UOE/CTED11/RC6
SEG22/RP19/CTED12/RC7
SEG13/AN9/RP11/CTED7/RC2
SEG17/SCL1/RP15/CTED8/RC3
SEG16/SDA1/RP17/CTED9/RC4
SEG12/RP16/CTED10/RC5
CTED6/PGD/RB7
OSC1/CLKI/RP10/RA7
OSC2/CLKO/RP6/RA6
SEG8/RP13/CTED4/RB5
SEG11/RP12/CTED3/RB4
SEG10/RP7/CTED2/RB3
SEG9/RP14/CTED1/RB2
VLCAP2/RP9/RB1
VLCAP1/RP8/CTED13/INT0/RB0
SEG7/RP27/REFO2/PSP7/RD7
SEG6/SCL2/RP26/PSP6/RD6
SEG5/SDA2/RP25/PSP5/RD5
SEG4/RP24/PSP4/RD4
SEG3/RP23/PSP3/RD3
SEG2/RP22/PSP2/RD2
SEG1/RP21/PSP1/RD1
SEG0/RP20/PSP0/RD0
LCDBIAS0/RP31/RE7
COM3/RP34/RE6
COM2/RP37/RE5
COM1/RP32/RE4
COM0/RP33/REFO1/RE3
LCDBIAS3/RP30/CS/RE2
VUSB3V3
PIC18F97J94 FAMILY
DS30575A-page 4 2012 Microchip Technology Inc.
Pin Diagrams (continued)
80
79
78
20
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
60
59
26
56
40
39
28
29
30
31
32
33
34
35
36
37
38
PIC18F87J94 (128K)
17
18
19
1
76
77
58
57
27
55
54
53
52
51
V
DD
AV
DD
V
DD
V
CAP
V
SS
Vss
V
SS
V
DD
75
74
73
71
72
70
69
68
66
67
65
64
63
61
62
50
49
46
48
47
45
44
43
42
41
21
23
24
25
22
AV
SS
Note: Pinouts are subject to change.
80-Pin TQFP
MCLR
VBAT
CTED6/PGD/RB7
CTED5/PGC/RB6
A18/SEG45/AN21/RH2
A19/SEG44/AN20/RH3
AD9/LCDBIAS2/RP29/WR/RE1
AD8/LCDBIAS1/RP28/RD/RE0
COM4/SEG28/AN8/RP46/RG0
COM5/SEG29/AN19/RP39/RG1
COM6/SEG30/AN18/C3INA/RP42/RG2
COM7/SEG31/AN17/C3INB/RP43/RG3
SEG26/AN16/C3INC/RP44/RTCC/RG4
SEG25/AN5/RP38/RF7
SEG24/AN11/C1INA/RP40/RF6
SEG23/CVREF/AN10/C1INB/RP35/RF5
D+/RF4
D-/RF3
SEG20/AN7/C2INB/RP36/RF2
SEG43/AN15/RH7
SEG42/AN14/C1INC/RH6
SEG41/AN13/C2IND/RH5
SEG40/AN12/C2INC/RH4
VUSB3V3
VREF+/AN3/RP3/RA3
SEG21/VREF-/AN2/RP2/RA2
SEG18/AN1/RP1/RA1
SEG19/AN0/AN1-/RP0/RA0
SEG15/AN4/LVDIN/C1INA/C2INA/C3INA/RP5/RA5
SEG14/AN6/RP4/RA4
SOSCI/RC1
SOSCO/SCLKI/PWRLCLK/RC0
SEG27/RP18/UOE/CTED11/RC6
SEG22/RP19/CTED12/RC7
BA0/SEG39/RJ4
CE/SEG38/RJ5
LB/SEG37/RJ6
UB/SEG36/RJ7
SEG13/AN9/RP11/CTED7/RC2
SEG17/SCL1/RP15/CTED8/RC3
SEG16/SDA1/RP17/CTED9/RC4
SEG12/RP16/CTED10/RC5
OSC1/CLKI/RP10/RA7
OSC2/CLKO/RP6/RA6
SEG8/RP13/CTED4/RB5
SEG11/RP12/CTED3/RB4
SEG10/RP7/CTED2/RB3
SEG9/RP14/CTED1/RB2
VLCAP2/RP9/RB1
VLCAP1/RP8/CTED13/INT0/RB0
WRH/SEG35/RJ3
WRL/SEG34/RJ2
OE/SEG33/RJ1
ALE/SEG32/RJ0
AD7/SEG7/RP27/REFO2/PSP7/RD7
AD6/SEG6/SCL2/RP26/PSP6/RD6
AD5/SEG5/SDA2/RP25/PSP5/RD5
AD4/SEG4/RP24/PSP4/RD4
AD3/SEG3/RP23/PSP3/RD3
AD2/SEG2/RP22/PSP2/RD2
AD1/SEG1/RP21/PSP1/RD1
VSS
AD0/SEG0/RP20/PSP0/RD0
AD15/LCDBIAS0/RP31/RE7
AD14/COM3/RP34/RE6
AD13/COM2/RP37/RE5
AD12/COM1/RP32/RE4
AD11/COM0/RP33/REFO1/RE3
AD10/LCDBIAS3/RP30/CS/RE2
A16/SEG47/AN23/RH0
A17/SEG46/AN22/RH1
2012 Microchip Technology Inc. DS30575A-page 5
PIC18F97J94 FAMILY
Pin Diagrams (continued)
92
94
93
91
90
89
88
87
86
85
84
83
82
81
80
79
78
20
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
65
64
63
62
61
60
59
26
56
45
44
43
42
41
40
39
28
29
30
31
32
33
34
35
36
37
38
PIC18F97J94 (128K)
17
18
19
21
22
95
1
76
77
72
71
70
69
68
67
66
75
74
73
58
57
24
23
25
96
98
97
99
27
46
47
48
49
50
55
54
53
52
51
100
V
SS
V
BAT
AV
DD
AV
SS
V
SS
V
DD
V
SS
V
CAP
VDD
V
DD
V
SS
Note: Pinouts are subject to change.
100-Pin TQFP
VDD
MCLR
SEG51/RL3
SEG52/RL4
UB/SEG36/RJ7
CTED6/PGD/RB7
SEG58/RK2
SEG59/RK3
CTED5/PGC/RB6
VSS
RG6
RG7
A18/SEG45/AN21/RH2
A19/SEG44/AN20/RH3
AD9/LCDBIAS2/RP29/WR/RE1
AD8/LCDBIAS1/RP28/RD/RE0
COM4/SEG28/AN8/RP46/RG0
COM5/SEG29/AN19/RP39/RG1
COM6/SEG30/AN18/C3INA/RP42/RG2
COM7/SEG31/AN17/C3INB/RP43/RG3
SEG49/RL1
SEG26/AN16/C3INC/RP44/RTCC/RG4
SEG50/RL2
SEG25/AN5/RP38/RF7
SEG24/AN11/C1INA/RP40/RF6
SEG23/CVREF/AN10/C1INB/RP35/RF5
D+/RF4
D-/RF3
SEG20/AN7/CTMUI/C2INB/RP36/RF2
SEG43/AN15/RH7
SEG42/AN14/C1INC/RH6
SEG41/AN13/C2IND/RH5
SEG40/AN12/C2INC/RH4
SEG53/RL5
VREF+/AN3/RP3/RA3
SEG21/VREF-/AN2/RP2/RA2
SEG18/AN1/RP1/RA1
SEG19/AN0/AN1-/RP0/RA0
SEG54/RL6
SEG55/RL7
SEG15/AN4/LVDIN/C1INA/C2INA/C3INA/RP5/RA5
SEG14/AN6/RP4/RA4
SOSCI/RC1
SOSCO/SCLKI/PWRLCLK/RC0
SEG56/RK0
SEG27/RP18/UOE/CTED11/RC6
SEG22/RP19/CTED12/RC7
BA0/SEG39/RJ4
CE/SEG38/RJ5
LB/SEG37/RJ6
SEG13/AN9/RP11/CTED7/RC2
SEG17/SCL1/RP15/CTED8/RC3
SEG57/RK1
SEG16/SDA1/RP17/CTED9/RC4
SEG12/RP16/CTED10/RC5
OSC1/CLKI/RP10/RA7
OSC2/CLKO/RP6/RA6
DDIO0/SEG60/RK4
SEG8/RP13/CTED4/RB5
SEG11/RP12/CTED3/RB4
SEG10/RP7/CTED2/RB3
SEG9/RP14/CTED1/RB2
DDIO1/SEG61/RK5
VLCAP2/RP9/RB1
VLCAP1/RP8/CTED13/INT0/RB0
WRH/SEG35/RJ3
WRL/SEG34/RJ2
OE/SEG33/RJ1
ALE/SEG32/RJ0
AD7/SEG7/RP27/REFO2/PSP7/RD7
AD6/SEG6/SCL2/RP26/PSP6/RD6
SEG62/RK6
AD5/SEG5/SDA2/RP25/PSP5/RD5
AD4/SEG4/RP24/PSP4/RD4
AD3/SEG3/RP23/PSP3/RD3
AD2/SEG2/RP22/PSP2/RD2
SEG63/RK7
AD1/SEG1/RP21/PSP1/RD1
AD0/SEG0/RP20/PSP0/RD0
SEG48/RL0
AD15/LCDBIAS0/RP31/RE7
AD14/COM3/RP34/RE6
AD13/COM2/RP37/RE5
AD12/COM1/RP32/RE4
AD11/COM0/RP33/REFO1/RE3
AD10/LCDBIAS3/RP30/CS/RE2
A16/SEG47/AN23/RH0
A17/SEG46/AN22/RH1
VUSB3V3
PIC18F97J94 FAMILY
DS30575A-page 6 2012 Microchip Technology Inc.
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 9
2.0 Guidelines for Getting Started with PIC18FJ Microcontrollers ................................................................................................... 31
3.0 Oscillator Configurations ............................................................................................................................................................ 37
4.0 Power-Managed Modes ............................................................................................................................................................. 65
5.0 Reset .......................................................................................................................................................................................... 85
6.0 Memory Organization ............................................................................................................................................................... 113
7.0 Flash Program Memory............................................................................................................................................................ 143
8.0 External Memory Bus ............................................................................................................................................................... 153
9.0 8 x 8 Hardware Multiplier.......................................................................................................................................................... 165
10.0 Interrupts .................................................................................................................................................................................. 167
11.0 I/O Ports ................................................................................................................................................................................... 197
12.0 Data Signal Modulator .............................................................................................................................................................. 235
13.0 Liquid Crystal Display (LCD) Controller.................................................................................................................................... 245
14.0 Timer0 Module ......................................................................................................................................................................... 281
15.0 Timer1/3/5 Modules.................................................................................................................................................................. 284
16.0 Timer2/4/6/8 Modules............................................................................................................................................................... 294
17.0 Real-Time Clock and Calendar (RTCC)................................................................................................................................... 297
18.0 Enhanced Capture/Compare/PWM (ECCP) Module................................................................................................................ 317
19.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 339
20.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 351
21.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 411
22.0 12-Bit A/D Converter with Threshold Scan............................................................................................................................... 435
23.0 Comparator Module.................................................................................................................................................................. 489
24.0 Comparator Voltage Reference Module ................................................................................................................................... 497
25.0 High/Low-Voltage Detect (HLVD)............................................................................................................................................. 501
26.0 Charge Time Measurement Unit (CTMU) ................................................................................................................................ 507
27.0 Universal Serial Bus (USB) ...................................................................................................................................................... 525
28.0 Special Features of the CPU.................................................................................................................................................... 553
29.0 Instruction Set Summary .......................................................................................................................................................... 575
30.0 Development Support............................................................................................................................................................... 625
31.0 Electrical Characteristics .......................................................................................................................................................... 629
32.0 Packaging Information.............................................................................................................................................................. 663
Appendix A: Revision History............................................................................................................................................................. 677
Index ................................................................................................................................................................................................. 679
2012 Microchip Technology Inc. DS30575A-page 7
PIC18F97J94 FAMILY
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
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The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision
of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
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When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are
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PIC18F97J94 FAMILY
DS30575A-page 8 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 9
PIC18F97J94 FAMILY
1.0 DEVICE OVERVIEW
This document contains device-specific information for
the following devices:
This family introduces a new line of low-voltage LCD
microcontrollers with Universal Serial Bus (USB). It
combines all the main traditional advantage of all
PIC18 microcontrollers, namely, high computational
performance and a rich feature set at an extremely
competitive price point. These features make the
PIC18F97J94 family a logical choice for many
high-performance applications, where cost is a primary
consideration.
1.1 Core Features
1.1.1 TECHNOLOGY
All of the devices in the PIC18F97J94 family incorporate
a range of features that can significantly reduce power
consumption during operation. Key items include:
•Alternate Run Modes: By clocking the controller
from the Timer1 source or the Internal RC oscilla-
tor, power consumption during code execution
can be reduced.
•Multiple Idle Modes: The controller can also run
with its CPU core disabled but the peripherals still
active. In these states, power consumption can be
reduced even further.
•On-the-Fly Mode Switching: The power-managed
modes are invoked by user code during operation,
allowing the user to incorporate power-saving ideas
into their application’s software design.
•XLP: An extra low-power Sleep, BOR, RTCC and
Watchdog Timer.
1.1.2 OSCILLATOR OPTIONS AND
FEATURES
All of the devices in the PIC18F97J94 family offer differ-
ent oscillator options, allowing users a range of choices
in developing application hardware. These include:
• Two Crystal modes (HS, MS)
• One External Clock mode (EC)
• A Phase Lock Loop (PLL) frequency multiplier,
which allows clock speeds of up to 64 MHz.
• A fast Internal Oscillator (FRC) block that provides
an 8 MHz clock (±0.15% accuracy) with Active
Clock Tuning (ACT) from USB or SOSC source.
- Offers multiple divider options from 8 MHz to
500 kHz
- Frees the two oscillator pins for use as
additional general purpose I/O
• A separate Low-Power Internal RC Oscillator
(LPRC) (31 kHz nominal) for low-power,
timing-insensitive applications.
The internal oscillator block provides a stable reference
source that gives the family additional features for
robust operation:
•Fail-Safe Clock Monitor (FSCM): This option
constantly monitors the main clock source against a
reference signal provided by the internal oscillator.
If a clock failure occurs, the controller is switched to
the internal oscillator, allowing for continued
low-speed operation or a safe application
shutdown.
•Two-Speed Start-up (IESO): This option allows
the internal oscillator to serve as the clock source
from Power-on Reset, or wake-up from Sleep
mode, until the primary clock source is available.
• PIC18F97J94 • PIC18F96J94
• PIC18F87J94 • PIC18F86J94
• PIC18F67J94 • PIC18F66J94
• PIC18F96J99 • PIC18F95J94
• PIC18F86J99 • PIC18F85J94
• PIC18F66J99 • PIC18F65J94
PIC18F97J94 FAMILY
DS30575A-page 10 2012 Microchip Technology Inc.
1.1.3 MEMORY OPTIONS
The PIC18F97J94 family provides ample room for
application code, from 32 Kbytes to 128 Kbytes of code
space. The Flash cells for program memory are rated
to last up to 20,000 erase/write cycles. Data retention
without refresh is conservatively estimated to be
greater than 10 years.
The Flash program memory is readable and writable.
During normal operation, the PIC18F97J94 family also
provides plenty of room for dynamic application data
with up to 3,578 bytes of data RAM.
1.1.4 UNIVERSAL SERIAL BUS (USB)
Devices in the PIC18F97J94 family incorporate a
fully-featured USB communications module with a
built-in transceiver that is compliant with the USB
Specification Revision 2.0. The module supports both
low-speed and full-speed communication for all
supported data transfer types.
1.1.5 EXTERNAL MEMORY BUS
Should 128 Kbytes of memory be inadequate for an
application, the 80-pin and 100-pin members of the
PIC18F97J94 family have an External Memory Bus
(EMB), enabling the controller’s internal Program
Counter to address a memory space of up to 2 Mbytes.
This is a level of data access that few 8-bit devices can
claim and enables:
• Using combinations of on-chip and external
memory of up to 2 Mbytes
• Using external Flash memory for reprogrammable
application code or large data tables
• Using external RAM devices for storing large
amounts of variable data
1.1.6 EXTENDED INSTRUCTION SET
The PIC18F97J94 family implements the optional
extension to the PIC18 instruction set, adding eight
new instructions and an Indexed Addressing mode.
Enabled as a device configuration option, the extension
has been specifically designed to optimize re-entrant
application code originally developed in high-level
languages, such as ‘C’.
1.1.7 EASY MIGRATION
All devices share the same rich set of peripherals. This
provides a smooth migration path within the device
family as applications evolve and grow.
The consistent pinout scheme, used throughout the
entire family, also aids in migrating to the next larger
device. This is true when moving between the 64-pin
members, between the 80-pin members, between the
100-pin members or even jumping from 64-pin to
80-pin to 100-pin devices.
The PIC18F97J94 family is also largely pin compatible
with other PIC18 families, such as the PIC18F87J90,
PIC18F87J11 and the PIC18F87J50. This allows a new
dimension to the evolution of applications, allowing
developers to select different price points within
Microchip’s PIC18 portfolio, while maintaining a similar
feature set.
1.2 LCD Controller
The on-chip LCD driver includes many features that
make the integration of displays in low-power applica-
tions easier. These include an integrated voltage regu-
lator with charge pump and an integrated internal
resistor ladder that allows contrast control in software
and display operation above device VDD.
2012 Microchip Technology Inc. DS30575A-page 11
PIC18F97J94 FAMILY
1.3 Other Special Features
•Communications: The PIC18F97J94 family
incorporates a range of serial communication
peripherals, including USB, four Enhanced
Addressable USARTs with IrDA, and two Master
Synchronous Serial Port MSSP modules capable
of both SPI and I2C™ (Master and Slave) modes
of operation.
•CCP Modules: PIC18F97J94 family devices
incorporate up to seven Capture/Compare/PWM
(CCP) modules. Up to six different time bases can
be used to perform several different operations at
once.
•ECCP Modules: The PIC18F97J94 family has
three Enhanced CCP (ECCP) modules to
maximize flexibility in control applications:
- Up to eight different time bases for
performing several different operations at
once
- Up to four PWM outputs for each module –
for a total of 12 PWMs
- Other beneficial features, such as polarity
selection, programmable dead time,
auto-shutdown and restart, and Half-Bridge
and Full-Bridge Output modes
•12-Bit A/D Converter: The PIC18F97J94 family
has a software selectable, 10/12-bit
Analog-to-Digital (A/D) Converter. It incorporates
programmable acquisition time, allowing for a
channel to be selected and a conversion to be
initiated without waiting for a sampling period, and
thus, reducing code overhead.
•Charge Time Measurement Unit (CTMU): The
CTMU is a flexible analog module that provides
accurate differential time measurement between
pulse sources, as well as asynchronous pulse
generation.
• Together with other on-chip analog modules, the
CTMU can precisely measure time, measure
capacitance or relative changes in capacitance, or
generate output pulses that are independent of
the system clock.
•LP Watchdog Timer (WDT): This enhanced
version incorporates a 22-bit prescaler, allowing
an extended time-out range that is stable across
operating voltage and temperature. See
Section 31.0 “Electrical Characteristics” for
time-out periods.
•Real-Time Clock and Calendar Module
(RTCC): The RTCC module is intended for appli-
cations requiring that accurate time be maintained
for extended periods of time, with minimum to no
intervention from the CPU.
• The module is a 100-year clock and calendar with
automatic leap year detection. The range of the
clock is from 00:00:00 (midnight) on January 1,
2000 to 23:59:59 on December 31, 2099.
1.4 Details on Individual Family
Members
Devices in the PIC18F97J94 family are available in
64-pin, 80-pin and 100-pin packages. Block diagrams
for the two groups are shown in Figure 1-1, Figure 1-2
and Figure 1-3.
The devices are differentiated from each other in these
ways:
• Flash Program Memory:
- PIC18FX5J94 – 32 Kbytes
- PIC18FX6J94 – 64 Kbytes
- PIC18FX6J99 – 96 Kbytes
- PIC18FX7J94 – 128 Kbytes
• Data RAM:
- All devices – 4 Kbytes
• I/O Ports:
- PIC18F6XJ9X (64-pin devices) – seven
bidirectional ports
- PIC18F8XJ9X (80-pin devices) – nine
bidirectional ports
- PIC18F9XJ9X (100-pin devices) – eleven
bidirectional ports
• A/D Channels:
- PIC18F6XJXX (64-pin devices) – 16 channels
- PIC18F8XJXX (80-pin devices) – 24 channels
- PIC18F9XJXX (100-pin devices) – 24 channels
All other features for devices in this family are identical.
These are summarized in Table 1-1, Tab l e 1-2 and
Table 1-3.
The pinouts for all devices are listed in Tabl e 1-4.
PIC18F97J94 FAMILY
DS30575A-page 12 2012 Microchip Technology Inc.
TABLE 1-1: DEVICE FEATURES FOR THE 64-PIN DEVICES
TABLE 1-2: DEVICE FEATURES FOR THE 80-PIN DEVICES
Features PIC18F65J94 PIC18F66J94 PIC18F66J99 PIC18F67J94
Operating Frequency DC – 64 MHz
Program Memory (Bytes) 32K 64K 96K 128K
Program Memory (Instructions) 16,384 32,768 49,152 65,536
Data Memory (Bytes) 4K 4K 4K 4K
Interrupt Sources 42 48
I/O Ports Ports A, B, C, D, E, F, G
Parallel Communications Parallel Slave Port (PSP)
Timers 8
Comparators 3
LCD 224 pixels
CTMU Yes
RTCC Yes
Enhanced Capture/Compare/PWM
Modules
3 ECCPs and 7 CCPs
Serial Communications Two MSSPs, Four Enhanced USARTs (EUSART) and USB
10/12-Bit Analog-to-Digital Module 16 Input Channels
Resets (and Delays) POR, BOR, CM RESET Instruction, Stack Full, Stack Underflow, MCLR,
WDT (PWRT, OST)
Instruction Set 75 Instructions, 83 with Extended Instruction Set Enabled
Packages 64-Pin QFN, 64-Pin TQFP
Features PIC18F85J94 PIC18F86J94 PIC18F86J99 PIC18F87J94
Operating Frequency DC – 64 MHz
Program Memory (Bytes) 32 K 64K 96K 128K
(Up to 2 Mbytes with Extended Memory)
Program Memory (Instructions) 16,384 32,768 49,152 65,536
Data Memory (Bytes) 4K 4K 4K 4K
Interrupt Sources 42 48
I/O Ports Ports A, B, C, D, E, F, G, H, J
Parallel Communications Parallel Slave Port (PSP)
Timers 8
Comparators 3
LCD 352 pixels
CTMU Yes
RTCC Yes
Enhanced Capture/Compare/PWM
Modules
3 ECCPs and 7 CCPs
Serial Communications Two MSSPs, Four Enhanced USARTs (EUSART) and USB
12-Bit Analog-to-Digital Module 24 Input Channels
Resets (and Delays) POR, BOR, CM RESET Instruction, Stack Full, Stack Underflow, MCLR,
WDT (PWRT, OST)
Instruction Set 75 Instructions, 83 with Extended Instruction Set Enabled
Packages 80-Pin TQFP
2012 Microchip Technology Inc. DS30575A-page 13
PIC18F97J94 FAMILY
TABLE 1-3: DEVICE FEATURES FOR THE 100-PIN DEVICES
Features PIC18F95J94 PIC18F96J94 PIC18F96J99 PIC18F97J94
Operating Frequency DC – 64 MHz
Program Memory (Bytes) 32 K 64K 96K 128K
(Up to 2 Mbytes with Extended Memory)
Program Memory (Instructions) 16,384 32,768 49,152 65,536
Data Memory (Bytes) 4K 4K 4K 4K
Interrupt Sources 42 48
I/O Ports Ports A, B, C, D, E, F, G, H, J, K, L
Parallel Communications Parallel Slave Port (PSP)
Timers 8
Comparators 3
LCD 480 pixels
CTMU Yes
RTCC Yes
Enhanced Capture/Compare/PWM
Modules
3 ECCPs and 7 CCPs
Serial Communications Two MSSPs, Four Enhanced USARTs (EUSART) and USB
12-Bit Analog-to-Digital Module 24 Input Channels
Resets (and Delays) POR, BOR, CM RESET Instruction, Stack Full, Stack Underflow, MCLR,
WDT (PWRT, OST)
Instruction Set 75 Instructions, 83 with Extended Instruction Set Enabled
Packages 100-Pin TQFP
PIC18F97J94 FAMILY
DS30575A-page 14 2012 Microchip Technology Inc.
FIGURE 1-1: 64-PIN DEVICE BLOCK DIAGRAM
PORTA
Data Latch
Data Memory
(4 Kbytes)
Address Latch
Data Address<12>
12
Access
BSR FSR0
FSR1
FSR2
inc/dec
logic
Address
412 4
PCH PCL
PCLATH
8
31-Level Stack
Program Counter
PRODLPRODH
8 x 8 Multiply
8
BITOP
8
8
ALU<8>
Address Latch
Program Memory
Data Latch
20
8
8
Table Pointer<21>
inc/dec logic
21
8
Data Bus<8>
Table Latch
8
12
3
PCLATU
PCU
Note 1: See Table 1-4 for I/O port pin descriptions.
2: RA6 and RA7 are only available as digital I/O in select oscillator modes. For more information, see Section 3.0 “Oscillator
Configurations”.
EUSART1
Comparator
MSSP1/2
3/52/4/6/8 CTMUTimer1 A/D
10/12-Bit
W
Instruction Bus <16>
STKPTR Bank
8
State Machine
Control Signals
Decode
8
8
EUSART2
ROM Latch
PORTC
PORTD
PORTE
PORTF
PORTG
RA<7:0>(1,2)
RC<7:0>(1)
RD<7:0>(1)
RE<7:0>(1)
RF<7:2>(1)
RG<4:0>(1)
PORTB
RB<7:0>(1)
OSC1/CLKI
OSC2/CLKO
VDD, VSS
Timing
Generation
MCLR
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
BOR and
HLVD
Precision
Reference
Band Gap
INTRC
Oscillator
Regulator
Voltage
VDDCORE/VCAP
8 MHz
Oscillator
Timer0
4/5/6/7/8/9/10 RTCC
Timer Timer
1/2/3
CCP ECCP
1/2/3 USB EUSART3 EUSART4
IR
Instruction
Decode and
Control
LCD
224 Pixels
2012 Microchip Technology Inc. DS30575A-page 15
PIC18F97J94 FAMILY
FIGURE 1-2: 80-PIN DEVICE BLOCK DIAGRAM
Instruction
Decode and
Control
Data Latch
Address Latch
Data Address<12>
12
Access
BSR FSR0
FSR1
FSR2
inc/dec
logic
Address
412 4
PCH PCL
PCLATH
8
31-Level Stack
Program Counter
PRODLPRODH
8 x 8 Multiply
8
BITOP
8
8
ALU<8>
Address Latch
Program Memory
Data Latch
20
8
8
Table Pointer<21>
inc/dec logic
21
8
Data Bus<8>
Table Latch
8
12
3
PCLATU
PCU
W
Instruction Bus <16>
STKPTR Bank
8
State Machine
Control Signals
Decode
8
8
ROM Latch
OSC1/CLKI
OSC2/CLKO
VDD, VSS MCLR
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Precision
Reference
Band Gap
Regulator
Voltage
VDDCORE/VCAP
PORTA
PORTC
PORTD
PORTE
PORTF
PORTG
RA<7:0>(1,2)
RC<7:0>(1)
RD<7:0>(1)
RF<7:2>(1)
RG<4:0>(1)
PORTB
RB<7:0>(1)
PORTH
RH<7:0>(1)
PORTJ
RJ<7:0>(1)
Note 1: See Table 1-4 for I/O port pin descriptions.
2: RA6 and RA7 are only available as digital I/O in select oscillator modes. See Section 3.0 “Oscillator Configurations” for
more information.
Timing
Generation
INTRC
Oscillator
8 MHz
Oscillator
RE<7:0>(1)
BOR and
HLVD
Data Memory
(4 Kbytes)
EUSART1
Comparator
MSSP1/2
3/52/4/6/8 CTMUTimer1 A/D
12-Bit
EUSART2
Timer0
4/5/6/7/8/9/10 RTCC
Timer Timer
1/2/3
CCP ECCP
1/2/3
System Bus Interface
AD<15:0>, A<19:16>
(Multiplexed with PORTD,
PORTE and PORTH)
USB
EUSART4 EUSART3 USBUSB EMB
IR
LCD
352 Pixels
PIC18F97J94 FAMILY
DS30575A-page 16 2012 Microchip Technology Inc.
FIGURE 1-3: 100-PIN DEVICE BLOCK DIAGRAM
Instruction
Decode and
Control
Data Latch
Address Latch
Data Address<12>
12
BSR FSR0
FSR1
FSR2
inc/dec
logic
Address
4124
PCH PCL
PCLATH
8
31-Level Stack
Program Counter
PRODLPRODH
8 x 8 Multiply
8
BITOP
8
8
ALU<8>
Address Latch
Program Memory
Data Latch
20
8
8
Table Pointer<21>
inc/dec logic
21
8
Data Bus<8>
Table Latch
8
IR
12
3
PCLATU
PCU
W
Instruction Bus <16>
STKPTR
8
State Machine
Control Signals
Decode
8
8
ROM Latch
OSC1/CLKI
OSC2/CLKO
VDD, VSS MCLR
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Precision
Reference
Band Gap
Regulator
Voltage
VDDCORE/VCAP
PORTA
PORTC
PORTD
PORTE
PORTF
PORTG
RA<7:0>(1,2)
RC<7:0>(1)
RD<7:0>(1)
RF<7:2>(1)
RG<4:0>,
PORTB
RB<7:0>(1)
PORTH
RH<7:0>(1)
PORTJ
RJ<7:0>(1)
Note 1: See Table 1-4 for I/O port pin descriptions.
2: RA6 and RA7 are only available as digital I/O in select oscillator modes. See Section 3.0 “Oscillator Configurations” for
more information.
Timing
Generation
INTRC
Oscillator
8 MHz
Oscillator
RE<7:0>(1)
BOR and
HLVD
Data Memory
(4 Kbytes)
EUSART1
Comparator
MSSP1/2
3/52/4/6/8 CTMUTimer1 A/D
12-Bit
EUSART2
Timer0
4/5/6/7/8/9/10 RTCC
Timer Timer
1/2/3
CCP ECCP
1/2/3
System Bus Interface
AD<15:0>, A<19:16>
(Multiplexed with PORTD,
PORTE and PORTH)
USB
PORTK
RK<7:0>(1)
PORTL
EUSART4 EUSART3 USBUSB EMB
RL<7:0>(1)
RG<7:6>(1)
Access
Bank
LCD
480 Pixels
2012 Microchip Technology Inc. DS30575A-page 17
PIC18F97J94 FAMILY
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
MCLR11 97 I ST Master Clear (input) or programming voltage (input).
This pin is an active-low Reset to the device.
OSC1/CLKI/RP10/RA7
OSC1
CLKI
RP10
RA7
61 49 39
I
I
I/O
I/O
ST
CMOS
ST/DIG
ST/DIG
Oscillator crystal or external clock input.
Oscillator crystal input.
External clock source input. Always associated with pin
function, OSC1. (See related OSC1/CLKI,OSC2/CLKO pins.)
Remappable Peripheral Pin 10 input/output.
General purpose I/O pin.
OSC2/CLKO/RP6/RA6
OSC2
CLKO
RP6
RA6
62 50 40
O
O
I/O
I/O
—
DIG
ST/DIG
ST/DIG
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or resonator in
Crystal Oscillator mode.
In certain oscillator modes, OSC2 pin outputs CLKO,
which has 1/4 the frequency of OSC1 and denotes the
instruction cycle rate.
Remappable Peripheral Pin 6 input/output.
General purpose I/O pin.
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
PIC18F97J94 FAMILY
DS30575A-page 18 2012 Microchip Technology Inc.
SEG19/AN0/AN1-/RP0/RA0
SEG19
AN0
AN1-
RP0
RA0
37 30 24
O
I
I
I/O
I/O
Analog
Analog
Analog
ST/DIG
ST/DIG
SEG19 output for LCD.
Analog Input 0.
A/D negative input channel.
Remappable Peripheral Pin 0 input/output.
General purpose I/O pin.
SEG18/AN1/RP1/RA1
SEG18
AN1
RP1
RA1
36 29 23
O
I
I/O
I/O
Analog
Analog
ST/DIG
ST/DIG
SEG18 output for LCD.
Analog Input 1.
Remappable Peripheral Pin 1 input/output.
General purpose I/O pin.
SEG21/VREF-/AN2/RP2/RA2
SEG21
VREF-
AN2
RP2
RA2
34 28 22
O
I
I
I/O
I/O
Analog
Analog
Analog
ST/DIG
ST/DIG
SEG21 output for LCD.
A/D reference voltage (low) input.
Analog Input 2.
Remappable Peripheral Pin 2 input/output.
General purpose I/O pin.
VREF+/AN3/RP3/RA3
VREF+
AN3
RP3
RA3
33 27 21
I
I
I/O
I/O
Analog
Analog
ST/DIG
ST/DIG
A/D reference voltage (high) input.
Analog Input 3.
Remappable Peripheral Pin 3 input/output.
General purpose I/O pin.
SEG14/AN6/RP4/RA4
SEG14
AN6
RP4
RA4
43 34 28
O
I
I/O
I/O
Analog
Analog
ST/DIG
ST/DIG
SEG14 output for LCD.
Analog Input 6.
Remappable Peripheral Pin 4 input/output.
General purpose I/O pin.
SEG15/AN4/LVDIN/C1INA/
C2INA/C3INA/RP5/RA5
SEG15
AN4
LVDIN
C1INA
C2INA
C3INA
RP5
RA5
42 33 27
O
I
I
I
I
I
I/O
I/O
Analog
Analog
Analog
Analog
Analog
Analog
ST/DIG
ST/DIG
SEG15 output for LCD.
Analog Input 4.
High/Low-Voltage Detect (HLVD) input.
Comparator 1 Input A.
Comparator 2 Input A.
Comparator 3 Input A.
Remappable Peripheral Pin 5 input/output.
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
2012 Microchip Technology Inc. DS30575A-page 19
PIC18F97J94 FAMILY
VLCAP1/RP8/CTED13/INT0/RB0
VLCAP1
RP8
CTED13
INT0
RB0
73 58 48
I
I/O
I
I
I/O
Analog
ST/DIG
ST
ST
ST/DIG
LCD Drive Charge Pump Capacitor Input 1.
Remappable Peripheral Pin 8 input/output.
CTMU Edge 13 input.
External Interrupt 0.
General purpose I/O pin.
VLCAP2/RP9/RB1
VLCAP2
RP9
RB1
72 57 47
I
I/O
I/O
Analog
ST/DIG
ST/DIG
LCD Drive Charge Pump Capacitor Input 2.
Remappable Peripheral Pin 9 input/output.
General purpose I/O pin.
SEG9/RP14/CTED1/RB2
SEG9
RP14
CTED1
RB2
70 56 46
O
I/O
I
I/O
Analog
ST/DIG
ST
ST/DIG
SEG9 output for LCD.
Remappable Peripheral Pin 14 input/output.
CTMU Edge 1 input.
General purpose I/O pin.
SEG10/RP7/CTED2/RB3
SEG10
RP7
CTED2
RB3
69 55 45
O
I/O
I
I/O
Analog
ST/DIG
ST
ST/DIG
SEG10 output for LCD.
Remappable Peripheral Pin 7 input/output.
CTMU Edge 2 input.
General purpose I/O pin.
SEG11/RP12/CTED3/RB4
SEG11
RP12
CTED3
RB4
68 54 44
O
I/O
I
I/O
Analog
ST/DIG
ST
ST/DIG
SEG11 output for LCD.
Remappable Peripheral Pin 12 input/output.
CTMU Edge 3 input.
General purpose I/O pin.
SEG8/RP13/CTED4/RB5
SEG8
RP13
CTED4
RB5
67 53 43
O
I/O
I
I/O
Analog
ST/DIG
ST
ST/DIG
SEG8 output for LCD.
Remappable Peripheral Pin 13 input/output.
CTMU Edge 4 input.
General purpose I/O pin.
PGC/CTED5/RB6
PGC
CTED5
RB6
65 52 42
I/O
I
I/O
ST/DIG
ST
ST/DIG
In-Circuit Debugger and ICSP™ programming clock pin.
CTMU Edge Input.
General purpose I/O pin.
PGD/CTED6/RB7
PGD
CTED6
RB7
58 47 37
I/O
I
I/O
ST/DIG
ST
ST/DIG
In-Circuit Debugger and ICSP™ programming data pin.
CTMU Edge 6 input.
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
PIC18F97J94 FAMILY
DS30575A-page 20 2012 Microchip Technology Inc.
SOSCO/SCLKI/PWRLCLK/RC0
SOSCO
SCLKI
PWRLCLK
RC0
45 36 30
O
I
I
I/O
—
ST
ST
ST/DIG
SOSC oscillator output.
Digital SOSC input.
SOSC input at 50 Hz or 60 Hz only
(RTCCLKSEL<1:0> = 11 or 10).
General purpose I/O pin.
SOSCI/RC1
SOSCI
RC1
44 35 29
I
I/O
Analog
ST/DIG
Timer1 oscillator input.
General purpose I/O pin.
SEG13/AN9/RP11/CTED7/RC2
SEG13
AN9
RP11
CTED7
RC2
53 43 33
O
I
I/O
I
I/O
Analog
Analog
ST/DIG
ST
ST/DIG
SEG13 output for LCD.
Analog Input 9.
Remappable Peripheral Pin 11 input/output.
CTMU Edge 7 input.
General purpose I/O pin.
SEG17/SCL1/RP15/CTED8/RC3
SEG17
SCL1
RP15
CTED8
RC3
54 44 34
O
I/O
I/O
I
I/O
Analog
I2C
ST/DIG
ST
ST/DIG
SEG17 output for LCD.
I2C clock input/output.
Remappable Peripheral Pin 15 input/output.
CTMU Edge 8 input.
General purpose I/O pin.
SEG16/SDA1/RP17/CTED9/RC4
SEG16
SDA1
RP17
CTED9
RC4
56 45 35
O
I/O
I/O
I
I/O
Analog
I2C
ST/DIG
ST
ST/DIG
SEG16 output for LCD.
I2C data input/output.
Remappable Peripheral Pin 17 input/output.
CTMU Edge 9 input.
General purpose I/O pin.
SEG12/RP16/CTED10/RC5
SEG12
RP16
CTED10
RC5
57 46 36
O
I/O
I
I/O
Analog
ST/DIG
ST
ST/DIG
SEG12 output for LCD.
Remappable Peripheral Pin 16 input/output.
CTMU Edge 10 input.
General purpose I/O pin.
SEG27/RP18/UOE/CTED11/RC6
SEG27
RP18
UOE/
CTED11
RC6
47 37 31
O
I/O
O
I
I/O
Analog
ST/DIG
DIG
ST
ST/DIG
SEG27 output for LCD.
Remappable Peripheral Pin 18 input/output.
External USB transceiver NOE output.
CTMU Edge 11 input.
General purpose I/O pin.
SEG22/RP19/CTED12/RC7
SEG22
RP19
CTED12
RC7
48 38 32
O
I/O
I
I/O
Analog
ST/DIG
ST
ST/DIG
SEG22 output for LCD.
Remappable Peripheral Pin 19 input/output.
CTMU Edge 12 input.
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
2012 Microchip Technology Inc. DS30575A-page 21
PIC18F97J94 FAMILY
AD0/SEG0/RP20/PSP0/RD0
AD0
SEG0
RP20
PSP0
RD0
90 72 58
I/O
O
I/O
I/O
I/O
TTL/DIG
Analog
ST/DIG
ST/DIG
ST/DIG
External Memory Address/Data 0.
SEG0 output for LCD.
Remappable Peripheral Pin 20 input/output.
Parallel Slave Port data.
General purpose I/O pin.
AD1/SEG1/RP21/PSP1/RD1
AD1
SEG1
RP21
PSP1
RD1
86 69 55
I/O
O
I/O
I/O
I/O
TTL/DIG
Analog
ST/DIG
ST/DIG
ST/DIG
External Memory Address/Data 1.
SEG1 output for LCD.
Remappable Peripheral Pin 21 input/output.
Parallel Slave Port data.
General purpose I/O pin.
AD2/SEG2/RP22/PSP2/RD2
AD2
SEG2
RP22
PSP2
RD2
84 68 54
I/O
O
I/O
I/O
I/O
TTL/DIG
Analog
ST/DIG
ST/DIG
ST/DIG
External Memory Address/Data 2.
SEG2 output for LCD.
Remappable Peripheral Pin 22 input/output.
Parallel Slave Port data.
General purpose I/O pin.
AD3/SEG3/RP23/PSP3/RD3
AD3
SEG3
RP23
PSP3
RD3
83 67 53
I/O
O
I/O
I/O
I/O
TTL/DIG
Analog
ST/DIG
ST/DIG
ST/DIG
External Memory Address/Data 3.
SEG3 output for LCD.
Remappable Peripheral Pin 3 input/output.
Parallel Slave Port data.
General purpose I/O pin.
AD4/SEG4/RP24/PSP4/RD4
AD4
SEG4
RP24
PSP4
RD4
82 66 52
I/O
O
I/O
I/O
I/O
TTL/DIG
Analog
ST/DIG
ST/DIG
ST/DIG
External Memory Address/Data 4.
SEG4 output for LCD.
Remappable Peripheral Pin 24 input/output.
Parallel Slave Port data.
General purpose I/O pin.
AD5/SEG5/SDA2/RP25/PSP5/RD5
AD5
SEG5
SDA2
RP25
PSP5
RD5
81 65 51
I/O
O
I/O
I/O
I/O
I/O
TTL/DIG
Analog
I2C
ST/DIG
ST/DIG
ST/DIG
External Memory Address/Data 5.
SEG5 output for LCD.
I2C data input/output.
Remappable Peripheral Pin 25 input/output.
Parallel Slave Port data.
General purpose I/O pin.
AD6/SEG6/SCL2/RP26/PSP6/RD6
AD6
SEG6
SCL2
RP26
PSP6
RD6
79 64 50
I/O
O
I/O
I/O
I/O
I/O
TTL/DIG
Analog
I2C
ST/DIG
ST/DIG
ST/DIG
External Memory Address/Data 6.
SEG6 output for LCD.
I2C clock input/output.
Remappable Peripheral Pin 26 input/output.
Parallel Slave Port data.
General purpose I/O pin.
AD7/SEG7/RP27/REFO2/
PSP7/RD7
AD7
SEG7
RP27
REFO2
PSP7
RD7
78 63 49
I/O
O
I/O
O
I/O
I/O
TTL/DIG
Analog
ST/DIG
DIG
ST/DIG
ST/DIG
External Memory Address/Data 7.
SEG7 output for LCD.
Remappable Peripheral Pin 27 input/output.
Reference output clock.
Parallel Slave Port data
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
PIC18F97J94 FAMILY
DS30575A-page 22 2012 Microchip Technology Inc.
AD8/LCDBIAS1/RP28/RD/RE0
AD8
LCDBIAS1
RP28
RD
RE0
4 4 2
I/O
I
I/O
I
I/O
TTL/DIG
Analog
ST/DIG
TTL
ST/DIG
External Memory Address/Data 8.
BIAS1 input for LCD.
Remappable Peripheral Pin 28 input/output.
Parallel Slave Port read strobe.
General purpose I/O pin.
AD9/LCDBIAS2/RP29/WR/RE1
AD9
LCDBIAS2
RP29
WR
RE1
3 3 1
I/O
I
I/O
I
I/O
TTL/DIG
Analog
ST/DIG
TTL
ST/DIG
External Memory Address/Data 9.
BIAS2 input for LCD.
Remappable Peripheral Pin 29 input/output.
Parallel Slave Port write strobe.
General purpose I/O pin.
AD10/LCDBIAS3/RP30/CS/RE2
AD10
LCDBIAS3
RP30
CS
RE2
98 78 64
I/O
I
I/O
I
I/O
TTL/DIG
Analog
ST/DIG
TTL
ST/DIG
External Memory Address/Data 10.
BIAS3 input for LCD.
Remappable Peripheral Pin 30 input/output.
Parallel Slave Port chip select.
General purpose I/O pin.
AD11/COM0/RP33/REFO1/RE3
AD11
COM0
RP33
REFO1
RE3
97 77 63
I/O
O
I/O
O
I/O
TTL/DIG
Analog
ST/DIG
DIG
ST/DIG
External Memory Address/Data 11.
COM0 output for LCD.
Remappable Peripheral Pin 33 input/output.
Reference output clock.
General purpose I/O pin.
AD12/COM1/RP32/RE4
AD12
COM1
RP32
RE4
95 76 62
I/O
O
I/O
I/O
TTL/DIG
Analog
ST/DIG
ST/DIG
External Memory Address/Data 12.
COM1 output for LCD.
Remappable Peripheral Pin 32 input/output.
General purpose I/O pin.
AD13/COM2/RP37/RE5
AD13
COM2
RP37
RE5
94 75 61
I/O
O
I/O
I/O
TTL/DIG
Analog
ST/DIG
ST/DIG
External Memory Address/Data 13.
COM2 output for LCD.
Remappable Peripheral Pin 37 input/output.
General purpose I/O pin.
AD14/COM3/RP34/RE6
AD14
COM3
RP34
RE6
93 74 60
I/O
O
I/O
I/O
TTL/DIG
Analog
ST/DIG
ST/DIG
External Memory Address/Data 14.
COM3 output for LCD.
Remappable Peripheral Pin 34 input/output.
General purpose I/O pin.
AD15/LCDBIAS0/RP31/RE7
AD15
LCDBIAS0
RP31
RE7
92 73 59
I/O
I
I/O
I/O
TTL/DIG
Analog
ST/DIG
ST/DIG
External Memory Address/Data 15.
BIAS0 input for LCD.
Remappable Peripheral Pin 31 input/output.
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
2012 Microchip Technology Inc. DS30575A-page 23
PIC18F97J94 FAMILY
SEG20/AN7/CTMUI/C2INB/RP36/
RF2
SEG20
AN7
CTMUI
C2INB
RP36
RF2
23 18 16
O
I
O
I
I/O
I/O
Analog
Analog
—
Analog
ST/DIG
ST/DIG
SEG20 output for LCD.
Analog Input 7.
CTMU pulse generator charger for the C2INB comparator input.
Comparator 2 Input B.
Remappable Peripheral Pin 36 input/output.
General purpose I/O pin.
D-/RF3
D-
RF3
22 17 15
I/O
I
—
ST
USB bus minus line input/output.
General purpose input pin.
D+/RF4
D+
RF4
20 16 14
I/O
I
—
ST
USB bus plus line input/output.
General purpose input pin.
SEG23/CVREF/AN10/C1INB/
RP35/RF5
SEG23
CVREF
AN10
C1INB
RP35
RF5
19 15 13
O
O
I
I
I/O
I/O
Analog
Analog
Analog
Analog
ST/DIG
ST/DIG
SEG23 output for LCD.
Comparator reference voltage output.
Analog Input 10.
Comparator 1 Input B.
Remappable Peripheral Pin 35 input/output.
General purpose I/O pin.
SEG24/AN11/C1INA/RP40/RF6
SEG24
AN11
C1INA
RP40
RF6
18 14 12
O
I
I
I/O
I/O
Analog
Analog
Analog
ST/DIG
ST/DIG
SEG24 output for LCD.
Analog Input 11.
Comparator 1 Input A.
Remappable Peripheral Pin 40 input/output.
General purpose I/O pin.
SEG25/AN5/RP38/RF7
SEG25
AN5
RP38
RF7
17 13 11
O
I
I/O
I/O
Analog
Analog
ST/DIG
ST/DIG
SEG25 output for LCD.
Analog Input 5.
Remappable Peripheral Pin 38 input/output.
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
PIC18F97J94 FAMILY
DS30575A-page 24 2012 Microchip Technology Inc.
COM4/SEG28/AN8/RP46/RG0
COM4
SEG28
AN8
RP46
RG0
6 5 3
O
O
I
I/O
I/O
Analog
Analog
Analog
ST/DIG
ST/DIG
COM4 output for LCD.
SEG28 output for LCD.
Analog Input 8.
Remappable Peripheral Pin 46 input/output.
General purpose I/O pin.
COM5/SEG29/AN19/RP39/RG1
COM5
SEG29
AN19
RP39
RG1
7 6 4
O
O
I
I/O
I/O
Analog
Analog
Analog
ST/DIG
ST/DIG
COM5 output for LCD.
SEG29 output for LCD.
Analog Input 19.
Remappable Peripheral Pin 39 input/output.
General purpose I/O pin.
COM6/SEG30/AN18/C3INA/RP42/
RG2
COM6
SEG30
AN18
C3INA
RP42
RG2
8 7 5
O
O
I
I
I/O
I/O
Analog
Analog
Analog
Analog
ST/DIG
ST/DIG
COM6 output for LCD.
SEG30 output for LCD.
Analog Input 18.
Comparator 3 Input A.
Remappable Peripheral Pin 42 input/output.
General purpose I/O pin.
COM7/SEG31/AN17/C3INB/RP43/
RG3
COM7
SEG31
AN17
C3INB
RP43
RG3
9 8 6
O
O
I
I
I/O
I/O
Analog
Analog
Analog
Analog
ST/DIG
ST/DIG
COM7 output for LCD.
SEG31 output for LCD.
Analog Input 17.
Comparator 3 Input B.
Remappable Peripheral Pin 43 input/output.
General purpose I/O pin.
SEG26/AN16/C3INC/RP44/RTCC/
RG4
SEG26
AN16
C3INC
RP44
RTCC
RG4
12 10 8
O
I
I
I/O
O
I/O
Analog
Analog
Analog
ST/DIG
—
ST/DIG
SEG26 output for LCD.
Analog Input 16.
Comparator 3 Input C.
Remappable Peripheral Pin 44 input/output.
RTCC output.
General purpose I/O pin.
RG6 89 I/O ST/DIG General purpose I/O pin.
RG7 96 I/O ST/DIG General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
2012 Microchip Technology Inc. DS30575A-page 25
PIC18F97J94 FAMILY
A16/SEG47/AN23/RH0
A16
SEG47
AN23
RH0
99 79
O
O
I
I/O
DIG
Analog
Analog
ST/DIG
External Memory Address 16.
SEG47 output for LCD.
Analog Input 23.
General purpose I/O pin.
A17/SEG46/AN22/RH1
A17
SEG46
AN22
RH1
100 80
O
O
I
I/O
DIG
Analog
Analog
ST/DIG
External Memory Address 17.
SEG46 output for LCD.
Analog Input 22.
General purpose I/O pin.
A18/SEG45/AN21/RH2
A18
SEG45
AN21
RH2
1 1
O
O
I
I/O
DIG
Analog
Analog
ST/DIG
External Memory Address 18.
SEG45 output for LCD.
Analog Input 21.
General purpose I/O pin.
A19/SEG44/AN20/RH3
A19
SEG44
AN20
RH3
2 2
O
O
I
I/O
DIG
Analog
Analog
ST/DIG
External Memory Address 19.
SEG44 output for LCD.
Analog Input 20.
General purpose I/O pin.
SEG40/AN12/C2INC/RH4
SEG40
AN12
C2INC
RH4
27 22
O
I
I
I/O
Analog
Analog
Analog
ST/DIG
SEG40 output for LCD.
Analog Input12.
Comparator 2 Input C.
General purpose I/O pin.
SEG41/AN13/C2IND/RH5
SEG41
AN13
C2IND
RH5
26 21
O
I
I
I/O
Analog
Analog
Analog
ST/DIG
SEG41 output for LCD.
Analog Input 13.
Comparator 2 Input D.
General purpose I/O pin.
SEG42/AN14/C1INC/RH6
SEG42
AN14
C1INC
RH6
25 20
O
I
I
I/O
Analog
Analog
Analog
ST/DIG
SEG42 output for LCD.
Analog Input 14.
Comparator 1 Input C.
General purpose I/O pin.
SEG43/AN15/RH7
SEG43
AN15
RH7
24 19
O
I
I/O
Analog
Analog
ST/DIG
SEG43 output for LCD.
Analog Input 15.
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
PIC18F97J94 FAMILY
DS30575A-page 26 2012 Microchip Technology Inc.
ALE/SEG32/RJ0
ALE
SEG32
RJ0
77 62
O
O
I/O
DIG
Analog
ST/DIG
External memory address latch enable.
SEG32 output for LCD.
General purpose I/O pin.
OE/SEG33/RJ1
OE
SEG33
RJ1
76 61
O
O
I/O
DIG
Analog
ST/DIG
External memory output enable.
SEG33 output for LCD.
General purpose I/O pin.
WRL/SEG34/RJ2
WRL
SEG34
RJ2
75 60
O
O
I/O
DIG
Analog
ST/DIG
External memory write low control.
SEG34 output for LCD.
General purpose I/O pin.
WRH/SEG35/RJ3
WRH
SEG35
RJ3
74 59
O
O
I/O
DIG
Analog
ST/DIG
External memory write high control.
SEG35 output for LCD.
General purpose I/O pin.
BA0/SEG39/RJ4
BA0
SEG39
RJ4
49 39
O
O
I/O
DIG
Analog
ST/DIG
External Memory Byte Address 0 control
SEG39 output for LCD.
General purpose I/O pin.
CE/SEG38/RJ5
CE
SEG38
RJ5
50 40
O
O
I/O
DIG
Analog
ST/DIG
External memory chip enable control.
SEG38 output for LCD.
General purpose I/O pin.
LB/SEG37/RJ6
LB
SEG37
RJ6
51 41
O
O
I/O
DIG
Analog
ST/DIG
External memory low byte control.
SEG37 output for LCD.
General purpose I/O pin.
UB/SEG36/RJ7
UB
SEG36
RJ7
52 42
O
O
I/O
DIG
Analog
ST/DIG
External memory high byte control.
SEG36 output for LCD.
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
2012 Microchip Technology Inc. DS30575A-page 27
PIC18F97J94 FAMILY
SEG56/RK0
SEG56
RK0
46
O
I/O
Analog
ST/DIG
SEG56 output for LCD.
General purpose I/O pin.
SEG57/RK1
SEG57
RK2
55
O
I/O
Analog
ST/DIG
SEG57 output for LCD.
General purpose I/O pin.
SEG58/RK2
SEG58
RK2
60
O
I/O
Analog
ST/DIG
SEG58 output for LCD.
General purpose I/O pin.
SEG59/RK3
SEG59
RK3
63
O
I/O
Analog
ST/DIG
SEG59 output for LCD.
General purpose I/O pin.
SEG60/RK4
SEG60
RK4
66
O
I/O
Analog
ST/DIG
SEG60 output for LCD.
General purpose I/O pin.
SEG61/RK5
SEG61
RK5
71
O
I/O
Analog
ST/DIG
SEG61 output for LCD.
General purpose I/O pin.
SEG62/RK6
SEG62
RK6
80
O
I/O
Analog
ST/DIG
SEG62 output for LCD.
General purpose I/O pin.
SEG63/RK7
SEG63
RK7
85
O
I/O
Analog
ST/DIG
SEG63 output for LCD.
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
PIC18F97J94 FAMILY
DS30575A-page 28 2012 Microchip Technology Inc.
SEG48/RL0
SEG48
RL0
91
O
I/O
Analog
ST/DIG
SEG48 output for LCD.
General purpose I/O pin.
SEG49/RL1
SEG49
RL1
10
O
I/O
Analog
ST/DIG
SEG49 output for LCD.
General purpose I/O pin.
SEG50/RL2
SEG50
RL3
13
O
I/O
Analog
ST/DIG
SEG50 output for LCD.
General purpose I/O pin.
SEG51/RL3
SEG51
RL4
16
O
I/O
Analog
ST/DIG
SEG51 output for LCD.
General purpose I/O pin.
SEG52/RL4
SEG52
RL4
21
O
I/O
Analog
ST/DIG
SEG52 output for LCD.
General purpose I/O pin.
SEG53/RL5
SEG53
RL5
30
O
I/O
Analog
ST/DIG
SEG53 output for LCD.
General purpose I/O pin.
SEG54/RL6
SEG54
RL6
38
O
I/O
Analog
ST/DIG
SEG54 output for LCD.
General purpose I/O pin.
SEG55/RL7
SEG55
RL7
41
O
I/O
Analog
ST/DIG
SEG55 output for LCD.
General purpose I/O pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
2012 Microchip Technology Inc. DS30575A-page 29
PIC18F97J94 FAMILY
VDD1
VDD2
VDD3
VDD4
5
40
59
88
32
48
71
26
38
57
P — Positive supply for logic and I/O pins.
VSS1
VSS2
VSS3
VSS4
Vss5
14
35
39
64
87
11
31
51
70
9
25
41
56
P — Ground reference for logic and I/O pins.
AVDD 31 25 19 P — Positive supply for analog modules.
AVSS 32 26 20 P — Ground reference for analog modules.
VDDCORE/VCAP
VDDCORE
VCAP
15 12 10
P
P
—
—
Core logic power or external filter capacitor connection.
External filter capacitor connection (regulator enabled/disabled).
VBAT 29 24 18 P —
VUSB3V328 23 17 P — USB voltage input pin.
TABLE 1-4: PIC18F97J94 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number Pin
Type
Buffer
Type Description
100 80 64
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to VDD)
I2C = I2C™/SMBus
PIC18F97J94 FAMILY
DS30575A-page 30 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 31
PIC18F97J94 FAMILY
2.0 GUIDELINES FOR GETTING
STARTED WITH PIC18FJ
MICROCONTROLLERS
2.1 Basic Connection Requirements
Getting started with the PIC18F97J94 family of 8-bit
microcontrollers requires attention to a minimal set of
device pin connection before proceeding with
development.
The following pins must always be connected:
•All V
DD and VSS pins
(see Section 2.2 “Power Supply Pins”)
•All AV
DD and AVSS pins, regardless of whether or
not the analog device features are used
(see Section 2.2 “Power Supply Pins”)
•MCLR
pin
(see Section 2.3 “Master Clear (MCLR) Pin”)
These pins must also be connected if they are being
used in the end application:
• PGC/PGD pins used for In-Circuit Serial
Programming™ (ICSP™) and debugging purposes
(see Section 2.5 “ICSP Pins”)
• OSC1 and OSC2 pins when an external oscillator
source is used
(see Section 2.6 “External Oscillator Pins”)
Additionally, the following pins may be required:
•V
REF+/VREF- pins are used when external voltage
reference for analog modules is implemented
The minimum mandatory connections are shown in
Figure 2-1.
FIGURE 2-1: RECOMMENDED
MINIMUM CONNECTIONS
Note: The AVDD and AVSS pins must always be
connected, regardless of whether any of
the analog modules are being used.
PIC18FXXJXX
VDD
VSS
VDD
VSS
VSS
VDD
AVDD
AVSS
VDD
VSS
C1
R1
VDD
MCLR
VCAP/VDDCORE
R2
C7
C2(2)
C3(2)
C4(2)
C5(2)
C6(2)
Key (all values are recommendations):
C1 through C6: 0.1 F, 20V ceramic
C7: 10 F, 6.3V or greater, tantalum or ceramic
R1: 10 kΩ
R2: 100Ω to 470Ω
Note 1: See Section 2.4 “Core Voltage Regulator
(VCAP/VDDCORE)” for explanation of
VCAP/VDDCORE connections.
2: The example shown is for a PIC18F device
with five VDD/VSS and AVDD/AVSS pairs.
Other devices may have more or less pairs;
adjust the number of decoupling capacitors
appropriately.
(1)
PIC18F97J94 FAMILY
DS30575A-page 32 2012 Microchip Technology Inc.
2.2 Power Supply Pins
2.2.1 DECOUPLING CAPACITORS
The use of decoupling capacitors on every pair of
power supply pins, such as VDD, VSS, AVDD and
AVSS, is required.
Consider the following criteria when using decoupling
capacitors:
•Value and type of capacitor: A 0.1 F (100 nF),
10-20V capacitor is recommended. The capacitor
should be a low-ESR device, with a resonance
frequency in the range of 200 MHz and higher.
Ceramic capacitors are recommended.
•Placement on the printed circuit board: The
decoupling capacitors should be placed as close
to the pins as possible. It is recommended to
place the capacitors on the same side of the
board as the device. If space is constricted, the
capacitor can be placed on another layer on the
PCB using a via; however, ensure that the trace
length from the pin to the capacitor is no greater
than 0.25 inch (6 mm).
•Handling high-frequency noise: If the board is
experiencing high-frequency noise (upward of
tens of MHz), add a second ceramic type capaci-
tor in parallel to the above described decoupling
capacitor. The value of the second capacitor can
be in the range of 0.01 F to 0.001 F. Place this
second capacitor next to each primary decoupling
capacitor. In high-speed circuit designs, consider
implementing a decade pair of capacitances as
close to the power and ground pins as possible
(e.g., 0.1 F in parallel with 0.001 F).
•Maximizing performance: On the board layout
from the power supply circuit, run the power and
return traces to the decoupling capacitors first,
and then to the device pins. This ensures that the
decoupling capacitors are first in the power chain.
Equally important is to keep the trace length
between the capacitor and the power pins to a
minimum, thereby reducing PCB trace
inductance.
2.2.2 TANK CAPACITORS
On boards with power traces running longer than
six inches in length, it is suggested to use a tank capac-
itor for integrated circuits, including microcontrollers, to
supply a local power source. The value of the tank
capacitor should be determined based on the trace
resistance that connects the power supply source to
the device, and the maximum current drawn by the
device in the application. In other words, select the tank
capacitor so that it meets the acceptable voltage sag at
the device. Typical values range from 4.7 F to 47 F.
2.3 Master Clear (MCLR) Pin
The MCLR pin provides two specific device
functions: Device Reset, and Device Programming
and Debugging. If programming and debugging are
not required in the end application, a direct
connection to VDD may be all that is required. The
addition of other components, to help increase the
application’s resistance to spurious Resets from
voltage sags, may be beneficial. A typical
configuration is shown in Figure 2-1. Other circuit
designs may be implemented, depending on the
application’s requirements.
During programming and debugging, the resistance
and capacitance that can be added to the pin must
be considered. Device programmers and debuggers
drive the MCLR pin. Consequently, specific voltage
levels (VIH and VIL) and fast signal transitions must
not be adversely affected. Therefore, specific values
of R1 and C1 will need to be adjusted based on the
application and PCB requirements. For example, it is
recommended that the capacitor, C1, be isolated
from the MCLR pin during programming and
debugging operations by using a jumper (Figure 2-2).
The jumper is replaced for normal run-time
operations.
Any components associated with the MCLR pin
should be placed within 0.25 inch (6 mm) of the pin.
FIGURE 2-2: EXAMPLE OF MCLR PIN
CONNECTIONS
Note 1: R1 10 k is recommended. A suggested
starting value is 10 k. Ensure that the
MCLR pin VIH and VIL specifications are met.
2: R2 470 will limit any current flowing into
MCLR from the external capacitor, C, in the
event of MCLR pin breakdown, due to
Electrostatic Discharge (ESD) or Electrical
Overstress (EOS). Ensure that the MCLR pin
VIH and VIL specifications are met.
C1
R2
R1
VDD
MCLR
PIC18FXXJXX
JP
2012 Microchip Technology Inc. DS30575A-page 33
PIC18F97J94 FAMILY
2.4 Core Voltage Regulator
(VCAP/VDDCORE)
A low-ESR (< 5Ω) capacitor is required on the VCAP pin
to stabilize the output voltage of the on-chip voltage
regulator. The VCAP pin must not be connected to VDD
and must use a capacitor of 10 μF connected to
ground. The type can be ceramic or tantalum. Suitable
examples of capacitors are shown in Table 2-1.
Capacitors with equivalent specification can be used.
Designers may use Figure 2-3 to evaluate ESR
equivalence of candidate devices.
It is recommended that the trace length not exceed
0.25 inch (6 mm). Refer to Section 31.0 “Electrical
Characteristics” for additional information.
FIGURE 2-3: FREQUENCY vs. ESR
PERFORMANCE FOR
SUGGESTED VCAP
.
10
1
0.1
0.01
0.001 0.01 0.1 1 10 100 1000 10,000
Frequency (MHz)
ESR ()
Note: Typical data measurement at 25°C, 0V DC bias.
TABLE 2-1: SUITABLE CAPACITOR EQUIVALENTS
Make Part # Nominal
Capacitance Base Tolerance Rated Voltage Temp. Range
TDK C3216X7R1C106K 10 µF ±10% 16V -55 to 125ºC
TDK C3216X5R1C106K 10 µF ±10% 16V -55 to 85ºC
Panasonic ECJ-3YX1C106K 10 µF ±10% 16V -55 to 125ºC
Panasonic ECJ-4YB1C106K 10 µF ±10% 16V -55 to 85ºC
Murata GRM32DR71C106KA01L 10 µF ±10% 16V -55 to 125ºC
Murata GRM31CR61C106KC31L 10 µF ±10% 16V -55 to 85ºC
PIC18F97J94 FAMILY
DS30575A-page 34 2012 Microchip Technology Inc.
2.4.1 CONSIDERATIONS FOR CERAMIC
CAPACITORS
In recent years, large value, low-voltage, surface-mount
ceramic capacitors have become very cost effective in
sizes up to a few tens of microfarad. The low-ESR, small
physical size and other properties make ceramic
capacitors very attractive in many types of applications.
Ceramic capacitors are suitable for use with the
VDDCORE voltage regulator of this microcontroller.
However, some care is needed in selecting the capac-
itor to ensure that it maintains sufficient capacitance
over the intended operating range of the application.
Typical low-cost, 10 µF ceramic capacitors are available
in X5R, X7R and Y5V dielectric ratings (other types are
also available, but are less common). The initial toler-
ance specifications for these types of capacitors are
often specified as ±10% to ±20% (X5R and X7R), or
-20%/+80% (Y5V). However, the effective capacitance
that these capacitors provide in an application circuit will
also vary based on additional factors, such as the
applied DC bias voltage and the temperature. The total
in-circuit tolerance is, therefore, much wider than the
initial tolerance specification.
The X5R and X7R capacitors typically exhibit satisfac-
tory temperature stability (ex: ±15% over a wide
temperature range, but consult the manufacturer’s data
sheets for exact specifications). However, Y5V capaci-
tors typically have extreme temperature tolerance
specifications of +22%/-82%. Due to the extreme
temperature tolerance, a 10 µF nominal rated Y5V type
capacitor may not deliver enough total capacitance to
meet minimum VDDCORE voltage regulator stability and
transient response requirements. Therefore, Y5V
capacitors are not recommended for use with the
VDDCORE regulator if the application must operate over
a wide temperature range.
In addition to temperature tolerance, the effective
capacitance of large value ceramic capacitors can vary
substantially, based on the amount of DC voltage
applied to the capacitor. This effect can be very signifi-
cant, but is often overlooked or is not always
documented.
A typical DC bias voltage vs. capacitance graph for
X7R type and Y5V type capacitors is shown in
Figure 2-4.
FIGURE 2-4: DC BIAS VOLTAGE vs.
CAPACITANCE
CHARACTERISTICS
When selecting a ceramic capacitor to be used with the
VDDCORE voltage regulator, it is suggested to select a
high-voltage rating, so that the operating voltage is a
small percentage of the maximum rated capacitor volt-
age. For example, choose a ceramic capacitor rated at
16V for the 2.5V VDDCORE voltage. Suggested
capacitors are shown in Table 2-1.
2.5 ICSP Pins
The PGC and PGD pins are used for In-Circuit Serial
Programming™ (ICSP™) and debugging purposes. It
is recommended to keep the trace length between the
ICSP connector and the ICSP pins on the device as
short as possible. If the ICSP connector is expected to
experience an ESD event, a series resistor is recom-
mended, with the value in the range of a few tens of
ohms, not to exceed 100Ω.
Pull-up resistors, series diodes, and capacitors on the
PGC and PGD pins are not recommended as they will
interfere with the programmer/debugger communica-
tions to the device. If such discrete components are an
application requirement, they should be removed from
the circuit during programming and debugging. Alter-
natively, refer to the AC/DC characteristics and timing
requirements information in the respective device
Flash programming specification for information on
capacitive loading limits, and pin input voltage high
(VIH) and input low (VIL) requirements.
For device emulation, ensure that the “Communication
Channel Select” (i.e., PGCx/PGDx pins), programmed
into the device, matches the physical connections for
the ICSP to the Microchip debugger/emulator tool.
For more information on available Microchip
development tools connection requirements, refer to
Section 30.0 “Development Support”.
-80
-70
-60
-50
-40
-30
-20
-10
0
10
5 1011121314151617
DC Bias Voltage (VDC)
Capacitance Change (%)
01234 67 89
16V Capacitor
10V Capacitor
6.3V Capacitor
2012 Microchip Technology Inc. DS30575A-page 35
PIC18F97J94 FAMILY
2.6 External Oscillator Pins
Many microcontrollers have options for at least two
oscillators: a high-frequency primary oscillator and a
low-frequency secondary oscillator (refer to
Section 3.0 “Oscillator Configurations” for details).
The oscillator circuit should be placed on the same
side of the board as the device. Place the oscillator
circuit close to the respective oscillator pins with no
more than 0.5 inch (12 mm) between the circuit
components and the pins. The load capacitors should
be placed next to the oscillator itself, on the same side
of the board.
Use a grounded copper pour around the oscillator cir-
cuit to isolate it from surrounding circuits. The
grounded copper pour should be routed directly to the
MCU ground. Do not run any signal traces or power
traces inside the ground pour. Also, if using a two-sided
board, avoid any traces on the other side of the board
where the crystal is placed.
Layout suggestions are shown in Figure 2-5. In-line
packages may be handled with a single-sided layout
that completely encompasses the oscillator pins. With
fine-pitch packages, it is not always possible to com-
pletely surround the pins and components. A suitable
solution is to tie the broken guard sections to a mirrored
ground layer. In all cases, the guard trace(s) must be
returned to ground.
In planning the application’s routing and I/O assign-
ments, ensure that adjacent port pins, and other
signals in close proximity to the oscillator, are benign
(i.e., free of high frequencies, short rise and fall times,
and other similar noise).
For additional information and design guidance on
oscillator circuits, please refer to these Microchip
Application Notes, available at the corporate web site
(www.microchip.com):
•AN826, “Crystal Oscillator Basics and Crystal
Selection for rfPIC™ and PICmicro® Devices”
• AN849, “Basic PICmicro® Oscillator Design”
• AN943, “Practical PICmicro® Oscillator Analysis
and Design”
•AN949, “Making Your Oscillator Work”
2.7 Unused I/Os
Unused I/O pins should be configured as outputs and
driven to a logic low state. Alternatively, connect a 1 kΩ
to 10 kΩ resistor to VSS on unused pins and drive the
output to logic low.
FIGURE 2-5: SUGGESTED PLACEMENT
OF THE OSCILLATOR
CIRCUIT
GND
`
`
`
OSC1
OSC2
T1OSO
T1OS I
Copper Pour Primary Oscillator
Crystal
Timer1 Oscillator
Crystal
DEVICE PINS
Primary
Oscillator
C1
C2
T1 Oscillator: C1 T1 Oscillator: C2
(tied to ground)
Single-Sided and In-Line Layouts:
Fine-Pitch (Dual-Sided) Layouts:
GND
OSC2
OSC1
Bottom Layer
Copper Pour
Oscillator
Crystal
Top Layer Copper Pour
C2
C1
DEVICE PINS
(tied to ground)
(tied to ground)
PIC18F97J94 FAMILY
DS30575A-page 36 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 37
PIC18F97J94 FAMILY
3.0 OSCILLATOR
CONFIGURATIONS
This section describes the PIC18F oscillator system
and its operation. The PIC18F oscillator system has the
following modules and features:
• A total of four external and internal oscillator
options as clock sources, providing up to
11 different clock modes
• An on-chip USB PLL block to provide a stable
48 MHz clock for the USB module, as well as a
range of frequency options for the system clock
• Software-controllable switching between various
clock sources
• Software-controllable postscaler for selective
clocking of CPU for system power savings
• A Fail-Safe Clock Monitor (FSCM) that detects
clock failure and permits safe application recovery
or shutdown
• A separate and independently configurable
system clock output for synchronizing external
hardware
A simplified diagram of the oscillator system is shown
in Figure 3-1.
FIGURE 3-1: PIC18F GENERAL SYSTEM CLOCK DIAGRAM
PIC18F97J94 Family
Secondary Oscillator
SOSCEN
Enable
Oscillator
SOSCO
SOSCI
Clock Source Option
for Other Modules
OSC1
OSC2
Primary Oscillator
MS, HS, EC
Peripherals
OSCCON3<2:0>
WDT, PWRT
8 MHz
FRCDIV
31 kHz (nominal)
FRC
Oscillator
SOSC
LPRC
Clock Control Logic
Fail-Safe
Clock
Monitor
FRC
(nominal)
8 MHz
4 MHz
PLL &
DIV
PLLDIV<3:0> CPDIV<1:0>
48 MHz USB Clock
USB PLL
Reference Clock
Generator
REFO
FRC
Active Clock
Control
Reference
from USB
D+/D-
REFOxCON2<7:0>
LPRC
Oscillator
MSPLL, HSPLL,
ECPLL, FRCPLL
Postscaler
FRCDIV 16 500 kHz
Tuning
PIC18F97J94 FAMILY
DS30575A-page 38 2012 Microchip Technology Inc.
3.1 CPU Clocking Scheme
The system clock source can be provided by one of
four sources:
• Primary Oscillator (POSC) on the OSC1 and
OSC2 pins
• Secondary Oscillator (SOSC) on the SOSCI and
SOSCO pins
• Fast Internal RC (FRC) Oscillator
• Low-Power Internal RC (LPRC) Oscillator
The Primary Oscillator and FRC sources have the option
of using the internal USB PLL block, which generates
both the USB module clock and a separate system clock
from the 96 MHz PLL. Refer to Section 3.8.1 “Oscilla-
tor Modes and USB Operation” for additional
information.
The internal FRC provides an 8 MHz clock source. It
can optionally be reduced by the programmable clock
divider to provide a range of system clock frequencies.
The selected clock source generates the processor
and peripheral clock sources. The processor clock
source is divided by four to produce the internal instruc-
tion cycle clock, FCY. In this document, the instruction
cycle clock is also denoted by FOSC/4. The internal
instruction cycle clock, FOSC/4, can be provided on the
OSC2 I/O pin for some operating modes of the Primary
Oscillator. The timing diagram in Figure 3-2 shows the
relationship between the processor clock source and
instruction execution.
FIGURE 3-2: CLOCK OR INSTRUCTION CYCLE TIMING
FOSC
PC
FCY
PC PC + 2 PC + 4
Fetch INST (PC)
Execute INST (PC – 2) Fetch INST (PC + 2)
Execute INST (PC) Fetch INST (PC + 4)
Execute INST (PC + 2)
TCY
2012 Microchip Technology Inc. DS30575A-page 39
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3.2 Oscillator Configuration
The oscillator source (and operating mode) that is used
at a device Power-on Reset (POR) event is selected
using Configuration bit settings. The Oscillator Configu-
ration bit settings are in the Configuration registers
located in the program memory (refer to Section 28.1
“Configuration Bits” for more information). The
Primary Oscillator Configuration bits, POSCMD<1:0>
(CONFIG3L<1:0>), and Oscillator Configuration bits,
FOSC<2:0> (CONFIG2L<2:0>), select the oscillator
source that is used at a POR. The FRC Oscillator with
Postscaler (FRCDIV) is the default (unprogrammed)
selection. The Secondary Oscillator, or one of the inter-
nal oscillators, may be chosen by programming these bit
locations.
The Configuration bits allow users to choose between
11 different clock modes, as shown in Ta b l e 3 - 1 .
TABLE 3-1: CONFIGURATION BIT VALUES FOR CLOCK SELECTION
Oscillator Mode Oscillator Source POSCMD<1:0> FOSC<2:0> Notes
Fast RC Oscillator with
Postscaler (FRCDIV)
Internal 11 111 1, 2
Fast RC Oscillator divided by 16
(FRC500kHz)
Internal 11 110 1
Low-Power RC Oscillator (LPRC) Internal 11 101 1
Secondary (Timer1) Oscillator
(SOSC)
Secondary 11 100 1
Primary Oscillator (HS) with PLL
Module (HSPLL)
Primary 10 011
Primary Oscillator (MS) with PLL
Module (MSPLL)
Primary 01 011
Primary Oscillator (EC) with PLL
Module (ECPLL)
Primary 00 011
Primary Oscillator (HS) Primary 10 010
Primary Oscillator (MS) Primary 01 010
Primary Oscillator (EC) Primary 00 010
Fast RC Oscillator with PLL Module
(FRCPLL)
Internal 11 001 1
Fast RC Oscillator (FRC) Internal 11 000 1
Note 1: OSC2 pin function is determined by the CLKOEN Configuration bit.
2: Default oscillator mode for an unprogrammed (erased) device.
PIC18F97J94 FAMILY
DS30575A-page 40 2012 Microchip Technology Inc.
3.2.1 CLOCK SWITCHING MODE
CONFIGURATION BITS
The FSCMx Configuration bits (CONFIG3L<5:4>) are
used to jointly configure device clock switching and the
Fail-Safe Clock Monitor (FSCM). Clock switching is
enabled only when FSCM1 is programmed (‘0’). The
FSCM is enabled only when FSCM<1:0> are both
programmed (‘00’).
3.2.2 OSC1 AND OSC2 PIN FUNCTIONS
IN NON-CRYSTAL MODES
When the Primary Oscillator on OSC1 and OSC2 is not
configured as the clock source (POSCMD<1:0> = 11),
the OSC1 pin is automatically reconfigured as a
digital I/O. In this configuration, as well as when the
Primary Oscillator is configured for EC mode
(POSCMD<1:0> = 00), the OSC2 pin can also be
configured as a digital I/O by programming the
CLKOEN Configuration bit (CONFIG2L<5>).
When CLKOEN is unprogrammed (‘1’), a FOSC/4 clock
output is available on OSC2 for testing or synchroniza-
tion purposes. With CLKOEN programmed (‘0’), the
OSC2 pin becomes a general purpose I/O pin. In both
of these configurations, the feedback device between
OSC1 and OSC2 is turned off to save current.
3.3 Control Registers
The operation of the oscillator is controlled by six
Special Function Registers (SFRs):
• OSCCON
• OSCCON2
• OSCCON3
• OSCCON4
• ACTCON
• OSCTUNE
3.3.1 OSCILLATOR CONTROL REGISTER
(OSCCON)
The OSCCON register (Register 3-1) is the main con-
trol register for the oscillator. It controls clock source
switching and allows the monitoring of clock sources.
The COSCx (OSCCON<6:4>) status bits are read-only
bits that indicate the current oscillator source the
device is operating from. The COSCx bits default to the
Internal Fast RC Oscillator with Postscaler (FRCDIV),
configured for 4 MHz, on a Power-on Reset (POR) and
Master Clear Reset (MCLR). A clock switch will
automatically be performed to the new oscillator source
selected by the FOSCx Configuration bits
(CONFIG2L<2:0>). The COSCx bits will change to indi-
cate the new oscillator source at the end of a clock
switch operation.
The NOSCx status bits select the clock source for the
next clock switch operation. On POR and MCLRs,
these bits automatically select the oscillator source
defined by the FOSCx Configuration bits. These bits
can be modified by software.
Setting the CLKLOCK bit (OSCCON2<7>) prevents
clock switching if the FSCM1 Configuration bit is set. If
the FSCM1 bit is clear, the CLKLOCK bit state is
ignored and clock switching can occur.
The IOLOCK bit (OSCCON2<6>) is used to unlock the
Peripheral Pin Select (PPS) feature; it has no function
in the system clock’s operation.
The LOCK status bit (OSCCON2<5>) is read-only and
indicates the status of the PLL circuit. It is set when the
PLL achieves a frequency lock and is reset when a
valid clock switching sequence is initiated. It reads as
‘0’ whenever the PLL is not used as part of the current
clock source.
The CF status bit (OSCCON2<3>) is a readable/clearable
status bit that indicates a clock failure; it is reset whenever
a valid clock switch occurs.
The POSCEN bit (OSCCON2<2>) is used to control
the operation of the Primary Oscillator in Sleep mode.
Setting this bit bypasses the normal automatic
shutdown of the oscillator whenever Sleep mode is
invoked.
The Secondary Oscillator can be turned on by a variety
of options:
• SOSCGO – OSCCON2<1>
• SOSCSEL – CONFIG2L<3>
• FOSC<2:0> – CONFIG2L<2:0>
• DSWDTOSC – CONFIG8H<1>
• RTCEN – RTCCON1<7>
• SOSCEN – T1CON<3>, T3CON<3> or
T5CON<3>
The ACTCON register (Register 3-10) controls the
Active Clock Tuning features.
2012 Microchip Technology Inc. DS30575A-page 41
PIC18F97J94 FAMILY
REGISTER 3-1: OSCCON: OSCILLATOR CONTROL REGISTER
R/W-0 R-x R-x R-x U-0 R/W-x R/W-x R/W-x
IDLEN COSC2 COSC1 COSC0 — NOSC2 NOSC1 NOSC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 IDLEN: Idle Enable bit
1 = SLEEP instruction invokes Idle mode
0 = SLEEP instruction invokes Sleep mode
bit 6-4 COSC<2:0>: Current Oscillator Selection bits (read-only)
000 = Fast RC Oscillator (FRC)
001 = Fast RC Oscillator (FRC), divided by N, with PLL module
010 = Primary Oscillator (MS, HS, EC)
011 = Primary Oscillator (MS, HS, EC) with PLL module
100 = Secondary Oscillator (SOSC)
101 = Low-Power RC Oscillator (LPRC)
110 = Fast RC Oscillator (FRC) divided by 16 (500 kHz)
111 = Fast RC Oscillator (FRC) divided by N
bit 3 Unimplemented: Read as ‘0’
bit 2-0 NOSC<2:0>: New Oscillator Selection bits
000 = Fast RC Oscillator (FRC)
001 = Fast RC Oscillator (FRC), divided by N, with PLL module
010 = Primary Oscillator (MS, HS, EC)
011 = Primary Oscillator (MS, HS, EC) with PLL module
100 = Secondary Oscillator (SOSC)
101 = Low-Power RC Oscillator (LPRC)
110 = Fast RC Oscillator (FRC) divided by 16 (500 kHz)
111 = Fast RC Oscillator (FRC) divided by N
PIC18F97J94 FAMILY
DS30575A-page 42 2012 Microchip Technology Inc.
REGISTER 3-2: OSCCON2: OSCILLATOR CONTROL REGISTER 2
R/W-0 R/W-0 R-0 U-0 R/C-0 R/W-0 R/W-0 U-0
CLKLOCK(2)IOLOCK(1)LOCK —CFPOSCENSOSCGO—
bit 7 bit 0
Legend: C = Clearable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CLKLOCK: Clock Lock Enabled bit(2)
1 = Clock and PLL selection are locked and may not be modified
0 = Clock and PLL selection are not locked, configurations may be modified
bit 6 IOLOCK: I/O Lock Enable bit(1)
1 = I/O lock is active (If IOL1WAY (CONFIG5H<0> = 1), the bit cannot be cleared, once it is set, except
on a device Reset.)
0 = I/O lock is not active
bit 5 LOCK: PLL Lock Status bit (read-only)
1 = Indicates that PLL module is in lock or PLL start-up timer is satisfied
0 = Indicates that PLL module is out of lock, PLL start-up timer is in progress or PLL is disabled
bit 4 Unimplemented: Read as ‘0’
bit 3 CF: Clock Fail Detect bit (readable/clearable by application)
1 = FSCM has detected a clock failure
0 = FSCM has not detected A clock failure
bit 2 POSCEN: Primary Oscillator (POSC) Enable bit
1 = Enables Primary Oscillator in Sleep mode
0 = Disables Primary Oscillator in Sleep mode
bit 1 SOSCGO: 32 kHz Secondary (LP) Oscillator Enable bit
1 = Enables Secondary Oscillator independent of other SOSC enable requests; provides a way to keep
the SOSC running even when not actively used by the system
0 = Disables Secondary Oscillator; the SOSC will be enabled if directly requested by the system. Reset
on POR or BOR only.
bit 0 Unimplemented: Read as ‘0’
Note 1: The IOLOCK bit cannot be cleared once it has been set, provided that the IOL1WAY (CONFIG5H<0>) = 1.
2: If the user wants to change the clock source, ensure that the FSCM<1:0> bits (CONFIG3L<5:4>) are set
appropriately.
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3.3.2 OSCCON3 – CLOCK DIVIDER
REGISTER (IRCF<2:0> BITS)
The IRCFx bits (OSCCON3<2:0>) select the postscaler
option for the FRC Oscillator output, allowing users to
choose a lower clock frequency than the nominal 8 MHz.
This option is described in more detail in Section 3.10.2
“FRC Postscaler Mode (FRCDIV)” and Section 3.10.3
“FRC Oscillator with PLL Mode (FRCPLL)”.
REGISTER 3-3: OSCCON3: OSCILLATOR CONTROL REGISTER 3
REGISTER 3-4: OSCCON4: OSCILLATOR CONTROL REGISTER 4
U-0 U-0 U-0 U-0 U-0 R/W-0 R/W-0 R/W-1
— — — — —IRCF2
(1)IRCF1(1)IRCF0(1)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-3 Unimplemented: Read as ‘0’
bit 2-0 IRCF<2:0>: Reference Clock Divider bits(1)
000 = FRC divide-by-1
001 = FRC divide-by-2 (default)
010 = FRC divide-by-4
011 = FRC divide-by-8
100 = FRC divide-by-16
101 = FRC divide-by-32
110 = FRC divide-by-64
111 = FRC divide-by-256
Note 1: The default FRC divide-by setting on an 8-bit device corresponds to 1 MIPS operation.
R/W-0 R/W-0 R/W-0 U-0 U-0 U-0 U-0 U-0
CPDIV1 CPDIV0 PLLEN — — — — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 CPDIV<1:0>: USB System Clock Select bits (postscaler select from 64 MHz clock branch)
00 = Input clock/1
01 = Input clock/2
10 = Input clock/4
11 = Input clock/8
bit 5 PLLEN: PLL Enable bit
1 = PLL is enabled even though it is not requested by the CPU; provides ability to “warm-up” the PLL
and keep it running to avoid the PLL start-up time. This setting will force the PLL and associated
clock source to stay active in Sleep.
0 = PLL is disabled; PLL will be automatically turned on when SRC1 is selected, or when REFO1 or
REFO2 is enabled and using the PLL clock as its source. In either case, the PLL will require a
start-up time.
bit 4-0 Unimplemented: Read as ‘0’
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3.3.3 OSCILLATOR TUNING REGISTER
(OSCTUNE)
The FRC Oscillator Tuning register (Register 3-5)
allows the user to fine-tune the FRC Oscillator. Refer to
the data sheet of the specific device for further
information regarding the FRC Oscillator tuning.
The tuning response of the FRC Oscillator may not be
monotonic or linear; the next closest frequency may be
offset by a number of steps. It is recommended that
users try multiple values of OSCTUNE to find the
closest value to the desired frequency.
REGISTER 3-5: OSCTUNE: FRC OSCILLATOR TUNING REGISTER
U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
—— TUN5 TUN4 TUN3 TUN2 TUN1 TUN0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at all Resets ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 TUN<5:0>: FRC Oscillator Tuning bits
011111 = Maximum frequency deviation
011110 =
.
.
.
000001 =
000000 = Center frequency; oscillator is running at factory calibrated frequency
111111 =
.
.
.
100001 =
100000 = Minimum frequency deviation
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3.4 Reference Clock Output Control
Module
The PIC18F97J94 family has two Reference Clock
Output (REFO) modules. Each of the Reference Clock
Output modules provides the user with the ability to
send out a programmed output clock onto the
REFO1or REFO2 pins.
3.4.1 REFERENCE CLOCK SOURCE
The module provides the ability to select one of the
following clock sources:
• Primary Crystal Oscillator (POSC)
• Secondary Crystal Oscillator (SOSC)
• 32.768 kHz Internal Oscillator (INTOSC)
• Fast Internal Oscillator (FRC)
It includes a programmable clock divider with ratios
ranging from 1:1 to 1:65534.
When the clock source is a crystal or internal oscillator,
the RSLP bit can be set to continue REFO operation
while the device is in Sleep Mode.
3.4.2 CLOCK SYNCHRONIZATION
The Reference Clock Output is enabled only once
(ON = 1). Note that the source of the clock and the
divider values should be chosen prior to the bit being
set to avoid glitches on the REFO output.
Once the ON bit is set, its value is synchronized to the
Reference Clock Output domain to enable the output.
This ensures that no glitches will be seen on the output.
Similarly, when the ON bit is cleared, the output and the
associated output enable signals will be synchronized
and disabled on the falling edge of the Reference Clock
Output. Note that with large divider values, this will
cause the REFO to be enabled for some period after
ON is cleared.
3.4.3 OPERATION IN SLEEP MODE
If any clock source, other than the peripheral clock, is
used as a base reference (i.e., ROSEL<3:0> 0001),
the user has the option to configure the behavior of the
oscillator in Sleep mode. The RSLP Configuration bit
determines if the oscillator will continue to run in Sleep.
If RSLP = 0, the oscillator will be shut down in Sleep
(assuming no other consumers are requesting it). If
RSLP = 1, the oscillator will continue to run in Sleep.
The Reference Clock Output is synchronized with the
Sleep signal to avoid any glitches on its output.
3.4.3.1 Module Enable Signal
The REFOx module may be enabled or disabled using
the REFOxMD register bit, which holds the REFOx
module in Reset, or the ON register bit, which does not.
3.4.3.2 Registers and Bits
This module provides the following device registers
and/or bits:
• REFOxCON – Reference Clock Output Control
Register
• REFOxCON1 – Reference Clock Output Control 1
Register
• REFOxCON2 – Reference Clock Output Control 2
Register
• REFOxCON3 – Reference Clock Output Control 3
Register
In addition, the REFOxCON1 module needs to be
enabled by clearing the REFOxMD disable bit
(PMD3<1>).
3.4.3.3 Interrupts
This module does not generate any interrupts.
Note: Throughout this section, references to
register and bit names that may be associ-
ated with specific Reference Clock Output
modules are referred to generically by the
use of ‘x’ in place of the specific module
number. Thus, “REFOxCON” might refer to
the control register for either REFO1 or
REFO2.
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REGISTER 3-6: REFOxCON: REFERENCE CLOCK OUTPUT CONTROL REGISTER
R/W-0 U-0 R/W-0 R/W-0 R/W-0 U-0 HC/R/W-0 HS/HC/R-0
ON —SIDLOERSLP
(1)— DIVSW_EN ACTIVE
bit 7 bit 0
Legend: HC = Hardware Clearable bit HS = Hardware Settable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at all Resets ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ON: Reference Clock Output Enable bit
1 = Reference clock module is enabled
0 = Reference clock module is disabled
bit 6 Unimplemented: Read as ‘0’
bit 5 SIDL: Peripheral Stop in Idle Mode bit
1 = Discontinues module operation when device enters Idle mode
0 = Continues module operation in Idle mode
bit 4 OE: Reference Clock Output Enable bit
1 = Reference clock is driven out on REFOx pin
0 = Reference clock is NOT driven out on REFOx pin
bit 3 RSLP: Reference Clock Output Run in Sleep bit(1)
1 = Reference Clock Output continues to run in Sleep
0 = Reference Clock Output is disabled in Sleep
bit 2 Unimplemented: Read as ‘0’
bit 1 DIVSW_EN: Clock RODIV Switch Enabled status bit
1 = Clock Divider Switching currently in progress
0 = Clock Divider Switching has completed
bit 0 ACTIVE: Reference Clock Output Request Status bit
1 = Reference clock request is active (user should not update the ROSEL and RODIV register fields)
0 = Reference clock request is not active (user may update the ROSEL and RODIV register fields)
Note 1: This bit has no effect when ROSEL<3:0> = 0000/0001, as the system clock and peripheral clock are
always disabled in Sleep mode on PIC18 devices.
2012 Microchip Technology Inc. DS30575A-page 47
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REGISTER 3-7: REFOxCON1: REFERENCE CLOCK OUTPUT CONTROL REGISTER 1
U-0 U-0 U-0 U-0 R/W-0(1)R/W-0(1)R/W-0(1)R/W-0(1)
———— ROSEL3 ROSEL2 ROSEL1 ROSEL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at all Resets ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 Unimplemented: Read as ‘0’
(Reserved for additional ROSEL bits.)
bit 3-0 ROSEL<3:0>: Reference Clock Output Source Select bits(1)
Select one of the various clock sources to be used as the reference clock.
0111-1111 = Reserved
0110 = PLL (4/6/8x or 96 MHz)
0101 =SOSC
0100 =LPRC
0011 =FRC
0010 =POSC
0001 = Peripheral clock (reference clock reflects any peripheral clock switching)
0000 = System clock (reference clock reflects any device clock switching)
When PLLDIV<3:0> (CONFIG2H<3:0>) = 1111, ROSEL<3:0> should not be set to ‘0110’.
Note 1: The ROSEL register field should not be written while the ACTIVE (REFOxCON<0>) bit is ‘1’; undefined
behavior will result.
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REGISTER 3-8: REFOxCON2: REFERENCE CLOCK OUTPUT CONTROL REGISTER 2
R/W-0(1)R/W-0(1)R/W-0(1)R/W-0(1)R/W-0(1)R/W-0(1)R/W -0(1)R/W -0(1)
RODIV7 RODIV6 RODIV5 RODIV4 RODIV3 RODIV2 RODIV1 RODIV0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at all Resets ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 RODIV<7:0>: Reference Clock Output Divider bits(1)
Reserved for expansion of RODIV<15>.
Note 1: The RODIV register field should not be written while the ACTIVE (REFOxCON<0>) bit is ‘1’; Undefined
behavior will result.
REGISTER 3-9: REFOxCON3: REFERENCE CLOCK OUTPUT CONTROL REGISTER 3
U-0 R/W-0(1)R/W-0(1)R/W-0(1)R/W-0(1)R/W-0(1)R/W-0(1)R/W-0(1)
— RODIV14 RODIV13 RODIV12 RODIV11 RODIV10 RODIV9 RODIV8
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at all Resets ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-0 RODIV<14:8>: Reference Clock Output Divider bits(1)
Used in conjunction with RODIV<7:0> to specify clock divider frequency.
111111111111111 = REFO clock is base clock frequency divided by 65,534 (32,767 * 2)
111111111111110 = REFO clock is base clock frequency divided by 65,532 (32,766 * 2)
•
•
•
000000000000011 = REFO clock is base clock frequency divided by 6 (3 * 2)
000000000000010 = REFO clock is base clock frequency divided by 4 (2 * 2)
000000000000001 = REFO clock is base clock frequency divided by 2 (1 * 2)
000000000000000 = REFO clock is the same frequency as the base clock (no divider)
Note 1: The RODIV register field should not be written while the ACTIVE (REFOxCON<0>) bit is ‘1’; undefined
behavior will result.
2012 Microchip Technology Inc. DS30575A-page 49
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3.5 Primary Oscillator (POSC)
The Primary Oscillator is available on the OSC1 and
OSC2 pins of the PIC18F family. In general, the Pri-
mary Oscillator can be configured for an external clock
input or an external crystal. Further details of the
Primary Oscillator operating modes are described in
subsequent sections. The Primary Oscillator has up to
6 operating modes, summarized in Ta b l e 3 - 2 .
TABLE 3-2: PRIMARY OSCILLATOR OPERATING MODES
The POSCMDx and FOSCx Configuration bits
(CONFIG3L<1:0> and CONFIG2L<2:0>, respectively)
select the operating mode of the Primary Oscillator.
The POSCMD<1:0> bits select the particular submode
to be used (MS, HS or EC), while the FOSC<2:0> bits
determine if the oscillator will be used by itself or with
the internal PLL. The PIC18F operates from the
Primary Oscillator whenever the COSCx bits
(OSCCON<6:4>) are set to ‘010’ or ‘011’.
Refer to the “Electrical Characteristics” section in
the specific device data sheet for further information
regarding frequency range for each crystal mode.
FIGURE 3-3: CRYSTAL OR CERAMIC RESONATOR OPERATION
(MS OR HS OSCILLATOR MODE)
Oscillator Mode Description OSC2 Pin Function
EC External clock input (0-64 MHz) FOSC/4
ECPLL External clock input (4-48 MHz), PLL enabled FOSC/4, Note 2
HS 10 MHz-32 MHz crystal Note 1
HSPLL 10 MHz-32 MHz crystal, PLL enabled Note 2
MS 3.5 MHz-10 MHz crystal Note 1
MSPLL 3.5 MHz-8 MHz crystal, PLL enabled Note 1
Note 1: External crystal is connected to OSC1 and OSC2 in these modes.
2: Available only in devices with special PLL blocks (such as the 96 MHz PLL); the basic 4x PLL block
generates clock frequencies beyond the device’s operating range.
C1(3)
C2(3)
XTAL
OSC2
RS(1)
OSC1
RF(2) Sleep
To Internal Logic
PIC18F
Note 1: A series resistor, Rs, may be required for AT strip cut crystals.
2: The internal feedback resistor, RF, is typically in the range of 2 to 10 M
3: See Section 3.6.5 “Determining the Best Values for Oscillator Components”.
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DS30575A-page 50 2012 Microchip Technology Inc.
3.5.1 SELECTING A PRIMARY
OSCILLATOR MODE
The main difference between the MS and HS modes is
the gain of the internal inverter of the oscillator circuit,
which allows the different frequency ranges. The MS
mode is a medium power, medium frequency mode.
HS mode provides the highest oscillator frequencies
with a crystal. OSC2 provides crystal feedback in both
HS and MS Oscillator modes.
The EC and HS modes that use the PLL circuit provide
the highest device operating frequencies. The oscilla-
tor circuit will consume the most current in these modes
because the PLL is enabled to multiply the frequency of
the oscillator.
In general, users should select the oscillator option with
the lowest possible gain that still meets their specifica-
tions. This will result in lower dynamic currents (IDD).
The frequency range of each oscillator mode is the
recommended frequency cutoff, but the selection of a
different gain mode is acceptable as long as a thorough
validation is performed (voltage, temperature and
component variations, such as resistor, capacitor and
internal oscillator circuitry).
The oscillator feedback circuit is disabled in all EC
modes. The OSC1 pin is a high-impedance input and
can be driven by a CMOS driver.
If the Primary Oscillator is configured for an external
clock input, the OSC2 pin is not required to support the
oscillator function. For these modes, the OSC2 pin can
be used as an additional device I/O pin or a clock out-
put pin. When the OSC2 pin is used as a clock output
pin, the output frequency is FOSC/4.
3.6 Crystal Oscillators and Ceramic
Resonators
In MS and HS modes, a crystal or ceramic resonator is
connected to the OSC1 and OSC2 pins to establish
oscillation (Figure 3-3). The PIC18F oscillator design
requires the use of a parallel cut crystal. Using a series
cut crystal may give a frequency out of the crystal
manufacturer’s specifications.
3.6.1 OSCILLATOR/RESONATOR
START-UP
As the device voltage increases from VSS, the oscillator
will start its oscillations. The time required for the oscil-
lator to start oscillating depends on many factors,
including:
• Crystal/resonator frequency
• Capacitor values used
• Series resistor, if used, and its value and type
• Device VDD rise time
• System temperature
• Oscillator mode selection of device (selects the
gain of the internal oscillator inverter)
• Crystal quality
• Oscillator circuit layout
• System noise
The course of a typical crystal or resonator start-up is
shown in Figure 3-4. Notice that the time to achieve
stable oscillation is not instantaneous.
FIGURE 3-4: EXAMPLE OSCILLATOR/RESONATOR START-UP CHARACTERISTICS
Voltage
Crystal Start-up Time
Time
Device VDD
Maximum VDD of System
0V
VIL
VIH
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3.6.2 PRIMARY OSCILLATOR START-UP
FROM SLEEP MODE
The most difficult time for the oscillator to start-up is
when waking up from Sleep mode. This is because the
load capacitors have both partially charged to some
quiescent value and phase differential at wake-up is
minimal. Thus, more time is required to achieve stable
oscillation. Also remember that low voltage, high tem-
peratures and the lower frequency clock modes also
impose limitations on loop gain, which in turn, affects
start-up.
Each of the following factors increases the start-up
time:
• Low-frequency design (with a Low Gain Clock
mode)
• Quiet environment (such as a battery-operated
device)
• Operating in a shielded box (away from the noisy
RF area)
• Low voltage
• High temperature
• Wake-up from Sleep mode
Circuit noise, on the other hand, may actually help to
“kick start” the oscillator and help to lower the oscillator
start-up time.
3.6.3 OSCILLATOR START-UP TIMER
In order to ensure that a crystal oscillator (or ceramic
resonator) has started and stabilized, an Oscillator
Start-up Timer (OST) is provided. The OST is a simple,
10-bit counter that counts 1024 TOSC cycles before
releasing the oscillator clock to the rest of the system.
This time-out period is designated as TOST. The ampli-
tude of the oscillator signal must reach the VIL and VIH
thresholds for the oscillator pins before the OST can
begin to count cycles.
The TOST interval is required every time the oscillator
has to restart (i.e., on POR, BOR and wake-up from
Sleep mode). The Oscillator Start-up Timer is applied to
the MS and HS modes for the Primary Oscillator, as well
as the Secondary Oscillator, SOSC (see Section 3.9
“Secondary Oscillator (SOSC)”).
3.6.4 TUNING THE OSCILLATOR
CIRCUIT
Since Microchip devices have wide operating ranges
(frequency, voltage and temperature, depending on the
part and version ordered), and external components
(crystals, capacitors, etc.) of varying quality and manu-
facture, validation of operation needs to be performed to
ensure that the component selection will comply with the
requirements of the application. There are many factors
that go into the selection and arrangement of these
external components. Depending on the application,
these may include any of the following:
• Amplifier gain
• Desired frequency
• Resonant frequency(s) of the crystal
• Temperature of operation
• Supply voltage range
• Start-up time
• Stability
• Crystal life
• Power consumption
• Simplification of the circuit
• Use of standard components
• Component count
3.6.5 DETERMINING THE BEST VALUES
FOR OSCILLATOR COMPONENTS
The best method for selecting components is to apply
a little knowledge, and a lot of trial measurement and
testing. Crystals are usually selected by their parallel
resonant frequency only; however, other parameters
may be important to your design, such as temperature
or frequency tolerance. Microchip Application Note
AN588, “PICmicro® Microcontroller Oscillator Design
Guide” is an excellent reference to learn more about
crystal operation and ordering information.
The PIC18F internal oscillator circuit is a parallel
oscillator circuit which requires that a parallel resonant
crystal be selected. The load capacitance is usually
specified in the 22 pF to 33 pF range. The crystal will
oscillate closest to the desired frequency, with a load
capacitance in this range. It may be necessary to alter
these values, as described later, in order to achieve
other benefits.
The clock mode is primarily chosen based on the
desired frequency of the crystal oscillator. The main dif-
ference between the MS and HS Oscillator modes is
the gain of the internal inverter of the oscillator circuit,
which allows the different frequency ranges. In general,
use the oscillator option with the lowest possible gain
that still meets specifications. This will result in lower
dynamic currents (IDD). The frequency range of each
oscillator mode is the recommended frequency cutoff,
but the selection of a different gain mode is acceptable
as long as a thorough validation is performed (voltage,
temperature and component variations, such as resis-
tor, capacitor and internal oscillator circuitry). C1 and
C2 should also be initially selected based on the load
capacitance, as suggested by the crystal manufacturer,
and the tables supplied in the device data sheet. The
values given in the device data sheet can only be used
as a starting point, since the crystal manufacturer, sup-
ply voltage, and other factors already mentioned, may
cause your circuit to differ from the one used in the
factory characterization process.
Ideally, the capacitance is chosen so that it will oscillate
at the highest temperature and the lowest VDD that the
circuit will be expected to perform under. High temper-
ature and low VDD both have a limiting effect on the
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loop gain, such that if the circuit functions at these
extremes, the designer can be more assured of proper
operation at other temperatures and supply voltage
combinations. The output sine wave should not be
clipped in the highest gain environment (highest VDD
and lowest temperature) and the sine output amplitude
should be large enough in the lowest gain environment
(lowest VDD and highest temperature) to cover the logic
input requirements of the clock, as listed in the device
data sheet. OSC1 may have specified VIL and VIH
levels (refer to the specific product data sheet for more
information).
A method for improving start-up is to use a value of C2
greater than C1. This causes a greater phase shift across
the crystal at power-up, which speeds oscillator start-up.
Besides loading the crystal for proper frequency
response, these capacitors can have the effect of lower-
ing loop gain if their value is increased. C2 can be
selected to affect the overall gain of the circuit. A higher
C2 can lower the gain if the crystal is being overdriven
(also see discussion on Rs). Capacitance values that are
too high can store and dump too much current through
the crystal, so C1 and C2 should not become excessively
large. Unfortunately, measuring the wattage through a
crystal is difficult, but if you do not stray too far from the
suggested values, you should not have to be concerned
with this.
A series resistor, Rs, is added to the circuit if after all
other external components are selected to satisfaction,
and the crystal is still being overdriven. This can be
determined by looking at the OSC2 pin, which is the
driven pin, with an oscilloscope. Connecting the probe
to the OSC1 pin will load the pin too much and nega-
tively affect performance. Remember that a scope
probe adds its own capacitance to the circuit, so this
may have to be accounted for in your design (i.e., if the
circuit worked best with a C2 of 22 pF and the scope
probe was 10 pF, a 33 pF capacitor may actually be
called for). The output signal should not be clipping or
flattened. Overdriving the crystal can also lead to the
circuit jumping to a higher harmonic level, or even,
crystal damage.
The OSC2 signal should be a clean sine wave that
easily spans the input minimum and maximum of the
clock input pin. An easy way to set this is to again test
the circuit at the minimum temperature and maximum
VDD that the design will be expected to perform in; then,
look at the output. This should be the maximum ampli-
tude of the clock output. If there is clipping, or the sine
wave is distorted near VDD and VSS, increasing load
capacitors may cause too much current to flow through
the crystal, or push the value too far from the manufac-
turer’s load specification. To adjust the crystal current,
add a trimmer potentiometer between the crystal
inverter output pin and C2, and adjust it until the sine
wave is clean. The crystal will experience the highest
drive currents at the low temperature and high VDD
extremes.
The trimmer potentiometer should be adjusted at these
limits to prevent overdriving. A series resistor, Rs, of
the closest standard value can now be inserted in place
of the trimmer. If Rs is too high, perhaps more than
20 k, the input will be too isolated from the output,
making the clock more susceptible to noise. If you find
a value this high is needed to prevent overdriving the
crystal, try increasing C2 to compensate or changing
the oscillator operating mode. Try to get a combination
where Rs is around 10 k or less, and load
capacitance is not too far from the manufacturer’s
specification.
3.7 External Clock Input
In EC mode, the OSC1 pin is in a high-impedance state
and can be driven by CMOS drivers. The OSC2 pin can
be configured as either an I/O or the clock output
(FOSC/4) by selecting the CLKOEN bit (CONFIG2L<5>).
With CLKOEN set (Figure 3-5), the clock output is avail-
able for testing or synchronization purposes. With
CLKOEN clear (Figure 3-6), the OSC2 pin becomes a
general purpose I/O pin. The feedback device between
OSC1 and OSC2 is turned off to save current.
FIGURE 3-5: EXTERNAL CLOCK INPUT
OPERATION (CLKOEN = 1)
FIGURE 3-6: EXTERNAL CLOCK INPUT
OPERATION (CLKOEN = 0)
3.8 Phase Lock Loop (PLL) Branch
The PLL module contains two separate PLL
submodules: PLLM and PLL96MHZ. The PLLM sub-
module is configurable as a 4x, 6x or 8x PLL. The
OSC1
FOSC/2
Clock from
External System
PIC18F
OSC2 (FOSC/4 output)
OSC1
I/O RA6 (General Purpose I/O)I/O
Clock from
External
PIC18F
System
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PLL96MHZ submodule runs at 96 MHz and requires an
input clock between 4 MHz and 48 MHz (a multiple of
4 MHz). These are selected through the PLLDIV<3:0>
bits.
FIGURE 3-7: BASIC OSCILLATOR BLOCK DIAGRAM
OSCMUX
Divide
by N
FRCDIV
FRC Oscillator (FRC)
Primary Oscillator (POSC)
PLL Module
(PLLM, PLL96MHZ)
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3.8.1 OSCILLATOR MODES AND USB
OPERATION
Because of the timing requirements imposed by USB,
an internal clock of 48 MHz is required at all times while
the USB module is enabled and not in a suspended
operating state. A method is provided to internally
generate both the USB and system clocks from a single
oscillator source. PIC18F97J94 family devices use the
same clock structure as most other PIC18 devices, but
include a two-branch PLL system to generate the two
clock signals.
The USB PLL block is shown in Figure 3-8. In this sys-
tem, the input from the Primary Oscillator is divided
down by a PLL prescaler to generate a 4 MHz output.
This is used to drive an on-chip 96 MHz PLL frequency
multiplier to drive the two clock branches. One branch
uses a fixed, divide-by-2 frequency divider to generate
the 48 MHz USB clock. The other branch uses a fixed,
divide-by-1.5 frequency divider and configurable PLL
prescaler/divider to generate a range of system clock
frequencies. The CPDIVx bits select the system clock
speed; available clock options are listed in Tab l e 3-3.
The USB PLL prescaler does not automatically sense
the incoming oscillator frequency. The user must manu-
ally configure the PLL divider to generate the required
4 MHz output, using the PLLDIV<3:0> Configuration
bits. This limits the choices for Primary Oscillator
frequency to a total of 8 possibilities, shown in Table 3-4.
FIGURE 3-8: 96 MHz PLL BLOCK
96 MHz
PLL
PLL Prescaler
PLLDIV<3:0>
Input from
POSC
Input from
FRC
÷12
÷ 8
÷ 6
÷ 5
÷ 4
÷ 3
÷ 2
÷ 1
0111
0110
0101
0100
0011
0010
0001
0000
÷ 2
÷ 1.5
48 MHz Clock
for USB Module
Postsclaer
÷64
÷63
...
÷17.50
÷17.00
...
÷1.25
127
126
...
65
64
...
1
Clock Output for
Display Interface
(DISPCLK)
÷ 2
0
G1CLKSEL
Graphics Clock
Option 2
Postsclaer
CPDIV<1:0>
÷ 8
÷ 4
÷ 2
÷ 1
11
10
01
00
PLL Output for
System Clock
4 MHz or
8 MHz
96 MHz Branch
96 MHz PLL
USB Clock
Graphics Clock
System Clock
4 MHz Branch
48 MHz Branch
FOSC<2:0>
2012 Microchip Technology Inc. DS30575A-page 55
PIC18F97J94 FAMILY
TABLE 3-3: SYSTEM CLOCK OPTIONS
DURING USB OPERATION
TABLE 3-4: VALID PRIMARY OSCILLATOR
CONFIGURATIONS FOR USB
OPERATIONS
3.8.2 CONSIDERATIONS FOR USING
THE PLL BLOCK
All PLL blocks use the LOCK bit (OSCCON2<5>) as a
read-only status bit to indicate the lock status of the
PLL. It is automatically set after the typical time delay
for the PLL to achieve lock, designated as TLOCK. It is
cleared at a POR and on clock switches when the PLL
is selected as a clock source. It remains clear when any
clock source not using the PLL is selected.
If the PLL does not stabilize properly during start-up,
the LOCK bit may not reflect the actual status of the
PLL lock, nor does it detect when the PLL loses lock
during normal operation. Refer to the ”Electrical Char-
acteristics” section in the specific device data sheet
for further information on the PLL lock interval.
Using any PLL block with the FRC Oscillator provides
a stable system clock for microcontroller operations.
USB operation is only possible with FRC Oscillators
that are implemented with ±1/4% frequency accuracy.
Serial communications using USART are only possible
when FRC Oscillators are implemented with ±2% fre-
quency accuracy. The PIC18F97J94 family is able to
meet the required oscillator accuracy for both USB and
USART providing stable communication by use of its
active clock tuning feature. Refer to Section 3.13.3
“Active Clock Tuning (ACT) Module” for more
information.
If an application is being migrated between PIC18F
platforms with different PLL blocks, the differences in
PLL and clock options may require the reconfiguration
of peripherals that use the system clock. This is partic-
ularly true with serial communication peripherals, such
as the USARTs.
3.9 Secondary Oscillator (SOSC)
In most PIC18F devices, the low-power Secondary
Oscillator (SOSC) is implemented to run with a
32.768 kHz crystal. The oscillator is located on the
SOSCO and SOSCI device pins, and serves as a sec-
ondary crystal clock source for low-power operation. It
is used to drive Timer1, Real-Time Clock and Calendar
(RTCC) and other modules requiring a clock signal
while in low-power operation.
3.9.1 ENABLING THE SECONDARY
OSCILLATOR
The operation of the SOSC is selected by the FOSCx
Configuration bits or by selection of the NOSCx bits
(OSCCON<2:0>). The SOSC can also be enabled by
setting the SOSCEN bit in Timer1, Timer3 or Timer5.
The SOSC has a long start-up time; therefore, to avoid
delays for peripheral start-up, the SOSC can be
manually started using one of the SOSCEN bits.
MCU Clock Division
(CPDIV<1:0>)
System Clock
Frequency
(Instruction Rate in
MIPS)
None (00)64MHz (16)
2 (01)32MHz (8)
4 (10)4MHz (4)
8 (11)2MHz (1)
(1)
Note 1: These options are not compatible with
USB operation. They may be used when-
ever the PLL branch is selected and the
USB module is disabled.
Input
Oscillator
Frequency
Clock Mode PLL Division
(PLLDIV<2:0>)
48 MHz ECPLL 12 (111)
32 MHz ECPLL 8 (110)
24 MHz HSPLL, ECPLL 6 (101)
20 MHz HSPLL, ECPLL 5 (100)
16 MHz HSPLL, ECPLL 4 (011)
12 MHz HSPLL, ECPLL 3 (010)
8 MHz ECPLL, MSPLL,
FRCPLL(1)
2 (001)
4 MHz ECPLL, MSPLL,
FRCPLL(1)
1 (000)
Note 1: FRCPLL with ±0.25% accuracy can be
used for USB operation.
Note: Because of USB clocking accuracy
requirements (±0.25%), not all PIC18F
devices support the use of the FRCPLL
system clock configuration for USB oper-
ation. Refer to the specific device data
sheet for details on the FRC Oscillator
module.
PIC18F97J94 FAMILY
DS30575A-page 56 2012 Microchip Technology Inc.
3.9.2 SECONDARY OSCILLATOR
OPERATION
3.9.2.1 Continuous Operation
The SOSC is always running when any of the SOSCEN
bits are set. Leaving the oscillator running at all times
allows a fast switch to the 32 kHz system clock for
lower power operation. Returning to the faster main
oscillator still requires an oscillator start-up time if it is a
crystal-type source. This start-up time can be avoided
on PLL clock sources by setting the PLLEN bit
(OSCCON4<5>) in advance of switching the clock
source.
In addition, the oscillator will need to remain running at
all times for Real-Time Clock (RTC) application using
Timer1 or the RTCC module. Refer to Section 14.
“Timers” and Section 29. “Real-Time Clock and
Calendar (RTCC)” in the “PIC18F Family Reference
Manual” for further details.
3.9.2.2 Intermittent Operation
When all SOSCEN bits are cleared, the oscillator will
only operate when it is selected as the current device
clock source (COSC<2:0> = 100). It will be disabled
automatically if it is the current device clock source and
the device enters Sleep mode.
3.9.3 OPERATING MODES
3.9.3.1 Digital Mode
The SOSCO pin can also be configured to operate as a
digital clock input. The SOSCO pin is configured as a
digital input by setting SOSCSEL (CONFIG2L<3>) = 10.
When running in this mode, the SOSCO/SCLKI pin will
operate as a digital input to the oscillator section, while
the SOSCI pin will function as a port pin. The crystal
driving circuit is disabled. The Oscillator Configuration
Fuse bits (FOSC<2:0>) and New Oscillator Selection
bits (NOSC<2:0>) have no effect.
3.10 Internal Fast RC Oscillator (FRC)
The FRC Oscillator is a fast (8 MHz nominal), internal
RC Oscillator. This oscillator is intended to be a precise
internal RC Oscillator accurate enough to provide the
clock frequency necessary to maintain baud rate toler-
ance for serial data transmissions, without the use of
an external crystal or ceramic resonator. The PIC18F
device operates from the FRC Oscillator whenever the
COSCx bits are ‘111’, ‘110’, ‘001’ or ‘000’.
3.10.1 ENABLING THE FRC OSCILLATOR
Since it serves as the system clock during device initial-
ization, the FRC Oscillator is always enabled at a POR.
After the device is configured and PWRT expires, FRC
remains active only if it is selected as the device clock
source.
3.10.2 FRC POSTSCALER MODE (FRCDIV)
Users are not limited to the nominal 8 MHz FRC output
if they wish to use the Fast Internal Oscillator as a clock
source. An additional FRC mode, FRCDIV, implements
a selectable postscaler that allows the choice of a lower
clock frequency, from 7 different options, plus the direct
8 MHz output. The postscaler is configured using the
IRCF<2:0> bits (OSCCON3<2:0>). Assuming a
nominal 8 MHz output, available lower frequency
options range from 4 MHz (divide-by-2) to 31 kHz
(divide-by-256). The range of frequencies allows users
the ability to save power at any time in an application
by simply changing the IRCFx bits.
The FRCDIV mode is selected whenever the COSCx
bits are ‘111’.
3.10.3 FRC OSCILLATOR WITH PLL MODE
(FRCPLL)
The FRCPLL mode is selected whenever the COSCx
bits are ‘001’. In addition, this mode only functions when
the direct or divide-by-2 FRC postscaler options are
selected (IRCF<2:0> = 000 or 001).
When using the 4x or 8x PLL option, the output of the
FRC postscaler may also be combined with the PLL to
produce a nominal system clock of 16 MHz, 32 MHz or
64 MHz. Although somewhat less precise in frequency
than using the Primary Oscillator with a crystal or reso-
nator, it allows high-speed operation of the device
without the use of external oscillator components.
For devices with the basic 4x PLL block, the output of the
FRC postscaler block may also be combined with the
PLL to produce a nominal system clock of either 16 MHz
or 32 MHz. Although somewhat less precise in fre-
quency than using the Primary Oscillator with a crystal or
resonator, it still allows high-speed operation of the
device without the use of external oscillator components.
When using the 96 MHz PLL block, the output of the
FRC postscaler block may also be combined with the
PLL to produce a nominal system clock of either
4 MHz, 8 MHz, 16 MHz or 32 MHz. It also produces a
48 MHz USB clock; however, this USB clock must be
generated with the FRC Oscillator meeting the
frequency accuracy requirement of USB for proper
operation. Refer to the specific device data sheet for
details on the FRC Oscillator electrical characteristics.
In cases where the frequency accuracy is not met for
USB operation, the FRCPLL mode should not be used
when USB is active.
Note: Using FRC postscaler values, other than
‘000‘or ‘001‘, will cause the clock input to
the PLL to be below the operating
frequency input range and may cause
undesirable operation.
2012 Microchip Technology Inc. DS30575A-page 57
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3.11 Internal Low-Power RC Oscillator
(LPRC)
The LPRC Oscillator is separate from the FRC and oscil-
lates at a nominal frequency of 31 kHz. LPRC is the
clock source for the Power-up Timer (PWRT), Watchdog
Timer (WDT) and FSCM circuits. It may also be used to
provide a low-frequency clock source option for the
device, in those applications where power consumption
is critical and timing accuracy is not required.
3.11.1 ENABLING THE LPRC OSCILLATOR
Since it serves the Power-up Timer (PWRT) clock
source, the LPRC Oscillator is enabled at POR events
whenever the on-board voltage regulator is disabled.
After the PWRT expires, the LPRC Oscillator will
remain on if any one of the following is true:
• The FSCM is enabled.
• The WDT is enabled.
• The LPRC Oscillator is selected as the system
clock (COSC<2:0> = 101).
If none of the above is true, the LPRC will shut off after
the PWRT expires.
3.12 Fail-Safe Clock Monitor (FSCM)
The Fail-Safe Clock Monitor (FSCM) allows the device
to continue to operate, even in the event of an oscillator
failure. The FSCM function is enabled by programming
the FSCMx (Clock Switch and Monitor) bits in
CONFIG3L<5:4>. FSCM is only enabled when the
FSCM<1:0> bits (CONFIG3L<5:4>) = 00. When FSCM
is enabled, the internal LPRC Oscillator will run at all
times (except during Sleep mode).
In the event of an oscillator failure, the FSCM will gener-
ate a clock failure trap and will switch the system clock
to the FRC Oscillator. The user will then have the option
to either attempt to restart the oscillator or execute a
controlled shutdown. FSCM will monitor the system
clock source regardless of its source or oscillator mode.
This includes the Primary Oscillator for all oscillator
modes and the Secondary Oscillator, SOSC, when
configured as the system clock.
The FSCM module takes the following actions when
switching to the FRC Oscillator:
1. The COSCx bits are loaded with ‘000’.
2. The CF status bit is set to indicate the clock
failure.
3.12.1 FSCM DELAY
On a POR, BOR or wake from Sleep mode event, a
nominal delay (TFSCM) may be inserted before the
FSCM begins to monitor the system clock source. The
purpose of the FSCM delay is to provide time for the
oscillator and/or PLL to stabilize when the PWRT is not
utilized. The FSCM delay will be generated after the
internal System Reset signal, SYSRST
, has been
released. Refer to Section 28.4 “Fail-Safe Clock
Monitor” for FSCM delay timing information.
The TFSCM interval is applied whenever the FSCM is
enabled and the EC, HS or SOSC Oscillator modes are
selected as the system clock.
3.12.2 FSCM AND SLOW OSCILLATOR
START-UP
If the chosen device oscillator has a slow start-up time
coming out of POR, BOR or Sleep mode, it is possible
that the FSCM delay will expire before the oscillator
has started. In this case, the FSCM will initiate a clock
failure trap. As this happens, the COSCx bits are
loaded with the FRC Oscillator selection. This will
effectively shut off the original oscillator that was trying
to start. The user can detect this situation and initiate a
clock switch back to the desired oscillator in the Trap
Service Routine (TSR).
3.12.3 FSCM AND WDT
The FSCM and the WDT both use the LPRC Oscillator
as their time base. In the event of a clock failure, the
WDT is unaffected and continues to run on the LPRC.
3.13 Clock Switching Operation
With few limitations, applications are free to switch
between any of the four clock sources (Primary, SOSC,
FRC and LPRC) under software control and at any
time. To limit the possible side effects that could result
from this flexibility, PIC18F devices have a safeguard
lock built into the switch process.
Note: For more information about the oscilla-
tor failure trap, refer to Section 10.0
“Interrupts”.
Note: Please refer to the “Electrical Character-
istics” section of the specific device data
sheet for TFSCM specification values.
Note: Primary Oscillator mode has three different
submodes (MS, HS and EC), which are
determined by the POSCMDx Configura-
tion bits. While an application can switch to
and from Primary Oscillator mode, in soft-
ware, it cannot switch between the different
primary submodes without reprogramming
the device.
PIC18F97J94 FAMILY
DS30575A-page 58 2012 Microchip Technology Inc.
3.13.1 ENABLING CLOCK SWITCHING
To enable clock switching, the FCKSM1 Configuration
bit must be programmed to ‘0’. If the FCKSM1 Config-
uration bit is unprogrammed (‘1’), the clock switching
function and Fail-Safe Clock Monitor function are
disabled; this is the default setting.
The NOSCx control bits (OSCCON<2:0>) do not control
the clock selection when clock switching is disabled. How-
ever, the COSCx bits (OSCCON<6:4>) will reflect the
clock source selected by the FOSC Configuration bits.
3.13.2 OSCILLATOR SWITCHING
SEQUENCE
At a minimum, performing a clock switch requires this
basic sequence:
1. If desired, read the COSCx bits (OSCCON<6:4>)
to determine the current oscillator source.
2. Clear the CLKLOCK bit (OSCCON2<7>) to
enable writes to the NOSCx bits (OSCCON<2:0>).
3. Write the appropriate value to the NOSCx control
bits (OSCCON<2:0>) for the new oscillator
source.
Once the basic sequence is completed, the system
clock hardware responds automatically as follows:
1. The clock switching hardware compares the
COSC status bits with the new value of the
NOSC control bits. If they are the same, then the
clock switch is a redundant operation. If they are
different, then a valid clock switch has been
initiated.
2. The new oscillator is turned on by the hardware
if it is not currently running. If a crystal oscillator
must be turned on, the hardware will wait until
the OST expires. If the new source is using the
PLL, then the hardware waits until a PLL lock is
detected (LOCK = 1).
3. The hardware waits for the new clock source to
stabilize and then performs the clock switch.
4. The hardware clears the OSWEN bit to indicate
a successful clock transition has occurred.
5. The NOSCx bit values are transferred to the
COSCx status bits.
6. The old clock source is turned off at this time,
with the exception of LPRC (if WDT or FSCM is
enabled) or SOSC (if it is enabled by one of the
timer sources).
The timing of the transition between clock sources is
shown in Figure 3-9.
FIGURE 3-9: CLOCK TRANSITION TIMING DIAGRAM
Note 1: The processor will continue to execute
code throughout the clock switching
sequence. Timing-sensitive code should
not be executed during this time.
2: Direct clock switches between any
Primary Oscillator mode with PLL and
FRCPLL mode are not permitted. This
applies to clock switches in either direc-
tion. In these instances, the application
must switch to FRC mode as a transition
clock source between the two PLL
modes.
Old Clock Source
New Clock Source
System Clock
Both Oscillators Active
New Source
Enabled
New Source
Stable
Old Source
Disabled
Note: The system clock can be any selected source (Primary, Secondary, FRC or LPRC).
NOSC = COSC
(old oscillator enabled)
NOSC ≠ COSC
(oscillator source in process of transition)
NOSC = COSC
(new oscillator
source enabled)
2012 Microchip Technology Inc. DS30575A-page 59
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A recommended code sequence for a clock switch
includes the following:
1. Disable interrupts during the OSCCON register
unlock and write sequence.
2. Clear the CLKLOCK bit (OSCCON2<7>) to
enable writes to the NOSCx bits (OSCCON<2:0>).
3. Write new oscillator source to NOSCx control bits.
4. Continue to execute code that is not
clock-sensitive (optional).
5. Invoke an appropriate amount of software delay
(cycle counting) to allow the selected oscillator
and/or PLL to start and stabilize.
6. Check to see if COSC contains the new oscillator
values that were requested in Step 3.
3.13.2.1 Clock Switching Considerations
When incorporating clock switching into an application,
users should keep certain things in mind when designing
their code.
• If the new clock source is a crystal oscillator, the
clock switch time will be dominated by the
oscillator start-up time.
• If the new clock source does not start, or is not
present, the clock switching hardware will wait
indefinitely for the new clock source. The user can
detect this situation because the COSCx bits will
not change to reflect the new desired oscillator
settings.
• Switching to a low-frequency clock source, such
as the Secondary Oscillator, will result in very
slow device operation.
3.13.3 ACTIVE CLOCK TUNING (ACT)
MODULE
The Active Clock Tuning (ACT) module continuously
adjusts the 8 MHz internal oscillator, using an
available external reference, to achieve ± 0.20%
accuracy. This eliminates the need for a high-speed,
high-accuracy external crystal when the system has
an available lower speed, lower power, high-accuracy
clock source available. Systems implementing a
Real-Time Clock Calendar (RTCC) or a full-speed
USB application can take full advantage of the ACT
module.
3.13.3.1 Active Clock Tuning Operation
The ACT module defaults to the disabled state after
any Reset. When the ACT module is disabled, the user
can write to the TUN<6:0> bits in the OSCTUNE
register to manually adjust the 8 MHz internal oscillator.
The module is enabled by setting the ACTEN bit of the
ACTCON register. When enabled, the ACT module
takes control of the OSCTUNE register. The ACT
module uses the selected ACT reference clock to tune
the 8 MHz internal oscillator to an accuracy of 8 MHz ±
0.2%. The tuning automatically adjusts the OSCTUNE
register every reference clock cycle.
3.13.3.2 Active Clock Tuning Source
Selection
The ACT reference clock is selected with the ACTSRC
bit of the ACTCON register. The reference clock
sources are provided by the:
• USB module in full-speed operation (ACT_clk)
• Secondary clock at 32.768 kHz (SOSC_clk)
3.13.3.3 ACT Lock Status
The ACTLOCK bit will be set to ‘1’, when the 8 MHz
internal oscillator is successfully tuned.
The bit will be cleared by the following conditions:
• Out of Lock condition
• Device Reset
• Module is disabled
3.13.3.4 ACT Out-of-Range Status
If the ACT module requires an OSCTUNE value
outside the range to achieve ± 0.20% accuracy, then
the ACT Out-of-Range (ACTORS) Status bit will be set
to ‘1’.
An out-of-range status can occur:
• When the 8 MHZ internal oscillator is tuned to its
lowest frequency and the next ACT_clk event
requests a lower frequency.
• When the 8 MHZ internal oscillator is tuned to its
highest frequency and the next ACT_clk event
requests a higher frequency.
When the ACT out-of-range event occurs, the 8 MHz
internal oscillator will continue to use the last written
OSCTUNE value. When the OSCTUNE value moves
back within the tunable range and ACTLOCK is
established, the ACTORS bit is cleared to ‘0’.
Note: The application should not attempt to
switch to a clock with a frequency lower
than 100 kHz when the FSCM is enabled.
Clock switching in these instances may
generate a false oscillator fail trap and
result in a switch to the Internal Fast RC
Oscillator.
PIC18F97J94 FAMILY
DS30575A-page 60 2012 Microchip Technology Inc.
FIGURE 3-10: ACTIVE CLOCK TUNING BLOCK DIAGRAM
Note 1: When the ACT module is enabled, the
OSCTUNE register is only updated by
the module. Writes to the OSCTUNE
register by the user are inhibited, but
reading the register is permitted.
2: After disabling the ACT module, the user
should wait three instructions before writ-
ing to the OSCTUNE register.
ACTSRC
FSUSB_clk
SOSC_clk
ACTEN
Active
Clock
Tuning
Module
ACT_clk Enable
ACTEN
Write
OSCTUNE
ACTEN
ACTUD
8 MHz
Internal OSC
1
0
OSCTUNE<6:0>
7
7
ACT data sfr data
2012 Microchip Technology Inc. DS30575A-page 61
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REGISTER 3-10: ACTCON: ACTIVE CLOCK TUNING (ACT) CONTROL REGISTER
Note 1: The ACTSRC bit should only be changed when ACTEN = 0.
R/W-0 U-0 R/W-0 R/W-0 R-0 R/W-0 R-0 R/W-0
ACTEN — ACTSIDL ACTSRC(1) ACTLOCK ACTLOCK-
POL
ACTORS ACTOR-
SPOL
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ACTEN: Active Clock Tuning Selection bit
1 = ACT module is enabled, updates to OSCTUNE are exclusive to the ACT module
0 = ACT module is disabled
bit 6 Unimplemented: Reads as ‘0’
bit 5 ACTSIDL: Active Clock Tuning Stop in Idle bit
1 = Active clock tuning stops during Idle mode
0 = Active clock tuning continues during Idle mode
bit 4 ACTSRC: Active Clock Tuning Source Selection bit
1 = The FRC oscillator is tuned to approximately match the USB host clock tolerance
0 = The FRC oscillator is tuned to approximately match the 32.768 kHz SOSC tolerance
bit 3 ACTLOCK: Active Clock Tuning Lock Status bit
1 = Locked; internal oscillator is within ± 0.20%
0 = Not locked; internal oscillator tuning has not stabilized within ± 0.20%
bit 2 ACTLOCKPOL: Active Clock Tuning Lock Interrupt Polarity bit
1 = ACT lock interrupt is generated when ACTLOCK is ‘0’
0 = ACT lock interrupt is generated when ACTLOCK is ‘1’
bit 1 ACTORS: Active Clock Tuning Out-of-Range Status bit
1 = Out-of-range; oscillator frequency is outside of the OSCTUNE range
0 = In-range; oscillator frequency is within the OSCTUNE range
bit 0 ACTORSPOL: Active Clock Tuning Out of Range Interrupt Polarity bit
1 = ACT out of range interrupt is generated when ACTORS is ‘0’
0 = ACT out of range interrupt is generated when ACTORS is ‘1’
PIC18F97J94 FAMILY
DS30575A-page 62 2012 Microchip Technology Inc.
3.13.4 ABANDONING A CLOCK SWITCH
In the event the clock switch does not complete, it can
be abandoned by setting the NOSCx bits to their previ-
ous values. This abandons the clock switch process,
stops and resets the OST (if applicable), and stops the
PLL (if applicable).
A clock switch procedure can be aborted at any time. A
clock switch that is already in progress can also be
aborted by performing a second clock switch.
3.13.5 ENTERING SLEEP MODE DURING
A CLOCK SWITCH
If the device enters Sleep mode during a clock switch
operation, the operation is abandoned. The processor
keeps the old clock selection and the NOSCx bits
return to their previous values (the same as COSC).
The SLEEP instruction is then executed normally.
3.14 Two-Speed Start-Up
Two-Speed Start-up is an automatic clock switching
feature that is independent of the manually controlled
clock switching previously described. It helps to mini-
mize the latency period, from oscillator start-up to code
execution, by allowing the microcontroller to use the
FRC Oscillator as a clock source until the primary clock
source is available. This feature is controlled by the
IESO Configuration bit (CONFIG2L<7>) and operates
independently of the state of the FSCM Configuration
bits.
Two-Speed Start-up is particularly useful when an
external oscillator is selected by the FOSCx Configura-
tion bits, and a crystal-based oscillator (either a
Primary or Secondary Oscillator) may have a longer
start-up time. As an internal RC Oscillator, the FRC
clock source is available almost immediately following
a POR or device wake-up.
With Two-Speed Start-up, the device starts executing
code on POR in its default oscillator configuration (FRC).
It continues to operate in this mode until the external
oscillator source, specified by the FOSCx Configuration
bits, becomes stable; at which time, it automatically
switches to that source.
Two-Speed Start-up is used on wake-up from the
power-saving Sleep mode. The device uses the FRC
clock source until the selected primary clock is ready. It is
not used in Idle mode, as the device will be clocked by the
currently selected clock source until the primary clock
source becomes available.
3.14.1 SPECIAL CONSIDERATIONS FOR
USING TWO-SPEED START-UP
While using the FRC Oscillator in Two-Speed Start-up,
the device still obeys the normal command sequences
for entering power-saving modes, including SLEEP
and IDLE instructions. In practice, this means that user
code can change the NOSC<2:0> bit settings or issue
#SLEEP instructions before the OST times out. This
would allow an application to briefly wake-up, perform
routine “housekeeping” tasks and return to Sleep
before the device starts to operate from the external
oscillator.
User code can also check which clock source is cur-
rently providing the device clocking by checking the
status of the COSC<2:0> bits against the NOSC<2:0>
bits. If these two sets of bits match, the clock switch has
been completed successfully and the device is running
from the intended clock source; the Primary Oscillator
is providing the clock. Otherwise, FRC is providing the
clock during wake-up from Reset or Sleep mode.
3.15 Reference Clock Output Module
(REFO1 and REFO2)
3.15.1 APPLICATIONS
The PIC18F97J94 family has two Reference Clock
Output modules. Each of the Reference Clock Output
modules provides the user with the ability to send out
a programmed output clock onto the REFO1or REFO2
pins.
3.15.2 REFERENCE CLOCK SOURCE
The module provides the ability to select one of the
following clock sources:
• Primary Crystal Oscillator (POSC)
• Secondary Crystal Oscillator (SOSC)
• 32.768 kHz Internal Oscillator (INTOSC)
• Fast Internal Oscillator (FRC)
• Raw System Clock (sys_clk)
• Peripheral Clock (p1_clk)
It includes a programmable clock divider with ratios
ranging from 1:1 to 1:65534.
When the clock source is a crystal or internal oscillator,
the RSLP bit (REFOxCON<3> can be set to continue
REFOx operation while the device is in Sleep Mode.
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3.15.3 CLOCK SYNCHRONIZATION
The Reference Clock Output is enabled only once
(ON = 1). Note that the source of the clock and the
divider values should be chosen prior to the bit being
set to avoid glitches on the REFO output.
Once the ON bit is set, its value is synchronized to the
reference clock domain to enable the output. This
ensures that no glitches will be seen on the output. Sim-
ilarly, when the ON bit is cleared, the output and the
associated output enable signals will be synchronized,
and disabled on the falling edge of the reference clock.
Note that with large divider values, this will cause the
REFO to be enabled for some period after ON is
cleared.
3.15.4 OPERATION IN SLEEP MODE
If any clock source, other than the peripheral clock, is
used as a base reference (i.e., ROSEL<3:0> 0001),
the user has the option to configure the behavior of the
oscillator in Sleep mode. The RSLP Configuration bit
determines if the oscillator will continue to run in
Sleep. If RSLP = 0, the oscillator will be shut down in
Sleep (assuming no other consumers are requesting
it). If RSLP = 1, the oscillator will continue to run in
Sleep.
The Reference Clock Output is synchronized with the
Sleep signal to avoid any glitches on its output.
3.15.5 MODULE ENABLE SIGNAL
The REFOx module may be enabled or disabled using
the REFOxMD register bit (PMD3, bit 1 or 0). The
module also needs to be turned on using the ON bit
(REFO1CON<7>).
3.15.5.1 Registers and Bits
This module provides the following device registers
and/or bits:
• REFOxCON – Reference Clock Output Control
Register
• REFOxCON1 – Reference Clock Output Control 1
Register
• REFOxCON2 – Reference Clock Output Control 2
Register
• REFOxCON3 – Reference Clock Output Control 3
Register
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NOTES:
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4.0 POWER-MANAGED MODES
All PIC18F97J94 family devices offer a number of
built-in strategies for reducing power consumption.
These strategies can be particularly useful in applica-
tions, which are both power-constrained (such as
battery operation), yet require periods of full-power
operation for timing-sensitive routines (such as serial
communications).
Aside from their low-power architecture, these devices
include an expanded range of dedicated hardware
features that allow the microcontroller to reduce power
consumption to even lower levels when long-term
hibernation is required, and still be able to resume
operation on short notice.
The device has four power-saving features:
• Instruction-Based Power-Saving Modes
• Hardware-Based Power Reduction Features
• Microcontroller Clock Manipulation
• Selective Peripheral Control
Combinations of these methods can be used to selec-
tively tailor an application’s power consumption, while
still maintaining critical or timing-sensitive application
features. However, it is more convenient to discuss the
strategies separately.
4.1 Overview of Power-Saving Modes
In addition to full-power operation, otherwise known as
Run mode, PIC18F97J94 family devices offer three
instruction-based, power-saving modes and one hard-
ware-based mode. In descending order of power
consumption, they are:
•Idle
• Sleep (including retention Sleep)
• Deep Sleep (with and without retention)
•V
BAT (with and without RTCC)
By powering down all four modes, different functional
areas of the microcontroller allow progressive reduc-
tions of operating and Idle power consumption. In addi-
tion, three of the modes can be tailored for more power
reduction at a trade-off of some operating features.
Table 4-1 lists all of the operating modes (including Run
mode, for comparison) in order of increasing power
savings and summarizes how the microcontroller exits
the different modes.
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DS30575A-page 66 2012 Microchip Technology Inc.
TABLE 4-1: SUMMARY OF OPERATING MODES FOR PIC18F97J94 FAMILY DEVICES WITH VBAT POWER-SAVING FEATURES
Mode Entry
Active Systems
Exit Conditions
Interrupts Resets
RTCC Alarm
(DS)WDT(3)
VDD Restore
Code Execution
Resumes
Core
Peripherals
Data RAM
Retention
RTCC(1)
DSGPRx(2)
All
INT0 Only
All
POR
MCLR
Run (default) N/A Y Y Y Y Y N/A N/A N/A N/A N/A N/A N/A N/A N/A
Idle Instruction N Y Y Y Y Y Y Y Y Y Y Y N/A Next Instruction
Sleep modes:
Sleep Instruction N N(4)Y Y Y Y Y Y Y Y Y Y N/A Next Instruction
Retention
Sleep
Instruction +
RETEN bit
NN
(4)YYYYYYYY Y YN/A
Deep Sleep modes:
Retention
Deep Sleep
Instruction +
DSEN bit +
RETEN bit
N N Y Y Y N Y N Y Y Y Y N/A Next Instruction
Deep Sleep Instruction +
DSEN bit
N N N Y Y N Y N Y Y Y Y N/A Reset Vector
VBAT:
with RTCC Hardware N N N Y Y N N N N N N N Y Reset Vector
w/o RTCC Hardware +
by disabling the
RTCC PMD bit
NNNNYNNNNNN N Y
Note 1: If RTCC is otherwise enabled in firmware.
2: Data retention in the DSGPR0, DSGPR1, DSGPR2 and DSGPR3 registers.
3: Deep Sleep WDT in Deep Sleep modes; WDT in all other modes.
4: Some select peripherals may continue to operate in this mode, using either the LPRC or an external clock source.
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4.2 Instruction-Based Power-Saving
Modes
PIC18F97J94 family devices have 3 instruction-based
power-saving modes; two of these have additional
features that allow for additional tailoring of power
consumption. All three modes are entered through the
execution of the SLEEP instruction. In descending order
of power consumption, they are:
• Idle Mode: The CPU is disabled, but the system
clock source continues to operate. Peripherals
continue to operate, but can optionally be
disabled.
• Sleep Modes: The CPU, system clock source and
any peripherals that operate on the system clock
source are disabled.
• Deep Sleep Modes: The CPU system clock
source, and all the peripherals except RTCC and
DSWDT are disabled. This is the lowest power
mode for the device. The power to RAM and
Flash is also disabled. Deep Sleep modes
represent the lowest power modes available
without removing power from the application.
Idle and Sleep modes are entered directly with the
SLEEP statement. Having IDLEN (OSCCON<7>) set
prior to the SLEEP statement will put the device into Idle
mode. For Deep Sleep mode, it is necessary to set the
DSEN bit (DSCONH<7>). To prevent inadvertent entry
into Deep Sleep mode, and possible loss of data, the
DSEN bit must be written to twice. The write need not
be consecutive instructions; however, it is a better
practice to write both, one after the other. It is also
recommended to clear the DSCON1 register before
setting the DSEN bit (Example 4-1).
EXAMPLE 4-1: SLEEP ASSEMBLY
SYNTAX
The instruction-based power-saving modes are exited
as a result of several different hardware triggers. When
the device exits one of these three operating modes, it
is said to ‘wake-up’. The characteristics of the
power-saving modes are described in the subsequent
sections.
4.2.1 INTERRUPTS COINCIDENT WITH
POWER SAVE INSTRUCTIONS
Any interrupt that coincides with the execution of a
SLEEP instruction will be held off until entry into Sleep,
Idle or Deep Sleep mode is completed. The device will
then wake-up from the power-managed mode.
Interrupts that occur during the Deep Sleep unlock
sequence will interrupt the mandatory unlock sequence
and cause a failure to enter Deep Sleep. For this
reason, it is recommended to disable all interrupts
during the Deep Sleep unlock sequence.
4.2.2 RETENTION REGULATOR
A second on-chip voltage regulator is used for power
management in Sleep and Deep Sleep modes. This
regulator, also known as the retention regulator, sup-
plies core logic and other circuits with power at a lower
VCORE level, about 1.2V nominal. Running these
circuits at a lower voltage allows for an additional
incremental power saving over the normal minimum
VCORE level.
In Retention Sleep modes, using the regulator main-
tains the entire data RAM and its contents, instead of
just a few protected registers. This allows the device to
exit a power-saving mode and resume code execution
as its previous state.
The retention regulator is controlled by the Configuration
bit, RETEN (CONFIG7L<0>), and the SRETEN bit
(RCON4<4>). The RETEN bit makes the retention
regulator available for software control. By default
(RETEN = 1), the regulator is disabled and the SRETEN
bit has no effect. Programming RETEN (= 0) allows the
SRETEN bit to control the regulator’s operation, leaving
its use in power-saving modes at the user’s discretion.
Setting the SRETEN bit prior to executing the SLEEP
instruction puts the device into Retention Sleep mode.
If the DSEN bit was also unlocked and set prior to the
instruction, the device will enter Retention Deep Sleep
mode.
The retention regulator is not available outside of
Sleep, Deep Sleep or VBAT modes. Enabling it while
the device is operating in Run or Idle modes does not
allow the device to operate at a lower level of VCORE.
Note: SLEEP_MODE and IDLE_MODE are con-
stants defined in the Assembler Include
file for the selected device.
clrf DSCON1
clrf DSCON1
bsf DSCON1,7
bsf DSCON1,7
sleep
or
movlw 0x80
movwf DSCON1
movwf DSCON1
sleep
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4.2.3 IDLE MODE
When the device enters Idle mode, the following events
occur:
• The CPU will stop executing instructions.
• The WDT is automatically cleared.
• The system clock source will remain active and
the peripheral modules, by default, will continue to
operate normally from the system clock source.
Peripherals can optionally be shut down in Idle
mode using their ‘Stop in Idle’ control bit. (See
peripheral descriptions for further details.)
• If the WDT or FSCM is enabled, the LPRC will
also remain active.
The processor will wake-up from Idle mode on the
following events:
• On any interrupt that is individually enabled.
• On any source of device Reset.
• On a WDT time-out.
Upon wake-up from Idle mode, the clock is reapplied to
the CPU and instruction execution begins immediately,
starting with the instruction following the SLEEP instruc-
tion, or the first instruction in the Interrupt Service
Routine (ISR).
4.2.3.1 Time Delays on Wake-up from Idle
Mode
Unlike a wake-up from Sleep mode, there are no addi-
tional time delays associated with wake-up from Idle
mode. The system clock is running during Idle mode,
therefore, no start-up times are required at wake-up.
4.2.3.2 Wake-up from Idle on Interrupt
Any source of interrupt that is individually enabled
using the corresponding control bit in the PIEx register,
will be able to wake-up the processor from Idle mode.
When the device wakes from Idle mode, one of two
options may occur:
• If the GIE bit is set, the processor will wake and
the Program Counter will begin execution at the
interrupt vector.
• If the GIE bit is not set, the processor will wake
and the Program Counter will continue execution
following the SLEEP instruction.
The PD status bit (RCON<2>) is set upon wake-up.
4.2.3.3 Wake-up from Idle on Reset
Any Reset, other than a Power-on Reset (POR), will
wake-up the CPU from Idle mode on any device Reset,
except a POR.
4.2.3.4 Wake-up from Idle on WDT Time-out
If the WDT is enabled, then the processor will wake-up
from Idle mode on a WDT time-out and continue code
execution with the instruction following the SLEEP
instruction that initiated Idle mode. Note that the WDT
time-out does not reset the device in this case. The TO
bit (RCON<3>) will be set.
4.2.4 SLEEP MODES
Most PIC18F97J94 family devices that incorporate
power-saving features and VBAT, offer two distinct
Sleep modes: Sleep mode and Retention Sleep mode.
The characteristics of both Sleep modes are:
• The system clock source is shut down. If an
on-chip oscillator is used, it is turned off.
• The device current consumption will be optimum,
provided no I/O pin is sourcing the current.
• The Fail-Safe Clock Monitor (FSCM) does not
operate during Sleep mode since the system
clock source is disabled.
• The LPRC clock will continue to run in Sleep
mode if the WDT is enabled.
• If Brown-out Reset (BOR) is enabled, the
Brown-out Reset (BOR) circuit remains
operational during Sleep mode.
• The WDT, if enabled, is automatically cleared
prior to entering Sleep mode.
• Some peripherals may continue to operate in
Sleep mode. These peripherals include I/O pins
that detect a change in the input signal or
peripherals that use an external clock input. Any
peripheral that operates from the system clock
source will be disabled in Sleep mode.
The processor will exit, or ‘wake-up’ from Sleep on one
of the following events:
• On any interrupt source that is individually
enabled
• On any form of device Reset
• On a WDT time-out
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4.2.4.1 Retention Sleep Mode
Retention Sleep mode allows for additional power sav-
ings over Sleep mode by maintaining key systems from
the lower power retention regulator. When the retention
regulator is used, the normal on-chip voltage regulator
(operating at 1.8V nominal) is turned off and will enable
a low-power (1.2V typical) regulator. By using a lower
voltage, a lower total power consumption is achieved.
Retention Sleep also offers the advantage of maintain-
ing the contents of the data RAM. As a trade-off, the
wake-up time is longer than that for Sleep mode.
Retention Sleep mode is controlled by the SRETEN bit
(RCON4<4>) and the RETEN Configuration bit, as
described in Section 4.2.2, Retention Regulator.
4.3 Clock Source Considerations
When the device wakes up from either of the Sleep
modes, it will restart the same clock source that was
active when Sleep mode was entered. Wake-up delays
for the different oscillator modes are shown in Table 4-3
and Ta bl e 4 - 4 , respectively.
If the system clock source is derived from a crystal oscil-
lator and/or the PLL, the Oscillator Start-up Timer (OST)
and/or PLL lock times must be applied before the system
clock source is made available to the device. As an
exception to this rule, no oscillator delays are necessary
if the system clock source is the Secondary Oscillator
and it was running while in Sleep mode.
4.3.1 SLOW OSCILLATOR START-UP
The OST and PLL lock times may not have expired
when the power-up delays have expired.
To avoid this condition, one can enable Two-Speed
Start-up by the device that will run on FRC until the
clock source is stable. Once the clock source is stable,
the device will switch to the selected clock source.
4.3.2 WAKE-UP FROM SLEEP ON
INTERRUPT
Any source of interrupt that is individually enabled, using
its corresponding control bit in the PIEx registers, can
wake-up the processor from Sleep mode. When the
device wakes from Sleep mode, one of two following
actions may occur:
• If the GIE bit is set, the processor will wake and
the Program Counter will begin execution at the
interrupt vector.
• If the GIE bit is not set, the processor will wake
and the Program Counter will continue execution
following the SLEEP instruction that initiated Sleep
mode.
4.3.3 WAKE-UP FROM SLEEP ON RESET
All sources of device Reset will wake-up the processor
from Sleep mode.
4.3.4 WAKE-UP FROM SLEEP ON
WATCHDOG TIME-OUT
If the Watchdog Timer (WDT) is enabled and expires
while the device is in Sleep mode, the processor will
wake-up. The SWDTEN status bit (RCON2<5>) is set
to indicate that the device resumed operation due to
the WDT expiration. Note that this event does not reset
the device. Operation continues from the instruction fol-
lowing the SLEEP instruction that initiated Sleep mode.
4.3.5 CONTROL BIT SUMMARY FOR
SLEEP MODES
Table 4-2 shows the settings for the bits relevant to
Sleep modes.
TABLE 4-2: BIT SETTINGS FOR ALL
SLEEP MODES
4.3.6 WAKE-UP DELAYS
The restart delay, associated with waking up from
Sleep and Retention Sleep modes, parallel each other
in terms of clock start-up times. They differ in the time
it takes to switch over from their respective regulators.
The delays for the different oscillator modes are shown
in Table 4-3 and Ta b l e 4 - 4 , respectively.
Mode DSEN
DSCONH<7>
Retention Regulator
RETEN
CONFIG7L<0>
SRETEN
RCON4<4> State
Sleep
x1x
Disabled
x00
Disabled
Retention
Sleep
x01
Enabled
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TABLE 4-3: DELAY TIMES FOR EXITING FROM SLEEP MODE
TABLE 4-4: DELAY TIMES FOR EXITING FROM RETENTION SLEEP MODE
Clock Source Exit Delay Oscillator Delay Notes
EC TPM —1
ECPLL TPM TLOCK 1, 3
MS, HS TPM TOST 1, 2
MSPLL, HSPLL TPM TOST + TLOCK 1, 2, 3
SOSC (Off during Sleep) TPM TOST 1, 2
(On during Sleep) TPM —1
FRC, FRCDIV TPM TFRC 1, 4
LPRC (Off during Sleep) TPM TLPRC 1, 4
(On during Sleep) TPM —1
FRCPLL TPM TLOCK 1, 3
Note 1: TPM = Start-up delay for program memory stabilization.
2: TOST = Oscillator Start-up Timer (OST); a delay of 1024 oscillator periods before the oscillator clock is
released to the system.
3: TLOCK = PLL lock time.
4: TFRC and TLPRC are RC Oscillator start-up times.
Clock Source Exit Delay Oscillator Delay Notes
EC TRETR + TPM —1, 2
ECPLL TRETR + TPM TLOCK 1, 2, 4
MS, HS TRETR + TPM TOST 1, 2, 3
MSPLL, HSPLL TRETR + TPM TOST + TLOCK 1, 2, 3, 4
SOSC (Off during Sleep) TRETR + TPM TOST 1, 2, 3
(On during Sleep) TRETR + TPM —1, 2
FRC, FRCDIV TRETR + TPM TFRC 1, 2, 5
LPRC (Off during Sleep) TRETR + TPM TLPRC 1, 2, 5
(On during Sleep) TRETR + TPM —1, 2
FRCPLL TRETR + TPM TLOCK 1, 2, 4
Note 1: TRETR = Retention regulator start-up delay.
2: TPM = Start-up delay for program memory stabilization; applicable only when IPEN (RCON<7>) = 0.
3: TOST = Oscillator Start-up Timer; a delay of 1024 oscillator periods before the oscillator clock is released to
the system.
4: TLOCK = PLL lock time.
5: TFRC and TLPRC are RC Oscillator start-up times.
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4.4 Deep Sleep Modes
The Deep Sleep modes puts the device into its lowest
power consumption states without requiring the use of
external switches to remove power from the device.
There are two modes available: Deep Sleep mode and
Retention Deep Sleep mode.
During both Deep Sleep modes, the power to the
microcontroller core is removed to reduce leakage
current. Therefore, most peripherals and functions of
the microcontroller become unavailable during Deep
Sleep. However, a few specific peripherals and func-
tions are powered directly from the VDD supply rail of
the microcontroller, and therefore, can continue to
function in Deep Sleep. In addition, four data memory
locations, DSGPR0, DSGPR1, DSGPR2 and
DSGPR3, are preserved for context information after
an exit from Deep Sleep.
Deep Sleep has a dedicated Deep Sleep Brown-out
Reset (DSBOR) and a Deep Sleep Watchdog Timer
Reset (DSWDT) for monitoring voltage and time-out
events in Deep Sleep mode. The DSBOR and DSWDT
are independent of the standard BOR and WDT used
with other power-managed modes (Run, Idle and
Sleep).
Entering Deep Sleep mode clears the Deep Sleep
Wake-up Source Registers (DSWAKEL and
DSWAKEH). If enabled, the Real-Time Clock and
Calendar (RTCC) continues to operate uninterrupted.
When a wake-up event occurs in Deep Sleep mode (by
Reset, RTCC alarm, External Interrupt (INT0) or
DSWDT), the device will exit Deep Sleep mode and
re-arm a Power-on Reset (POR). When the device is
released from Reset, code execution will resume at the
Reset vector.
4.4.1 RETENTION DEEP SLEEP MODE
In Retention Deep Sleep, the retention regulator is
enabled, which allows the data RAM to retain data
while all other systems are powered down. This also
allows the device to return to code execution where it
left off, instead of going through a POR-like Reset.
As a trade-off, Retention Deep Sleep mode has greater
power consumption than Deep Sleep. However, it
offers the lowest level of power consumption of the
power-saving modes that still allows a direct return to
code execution.
Retention Deep Sleep is controlled by the SRETEN bit
(RCON4<4>) and the RETEN Configuration bit, as
described in Section 4.2.2 “Retention Regulator”.
4.4.2 ENTERING DEEP SLEEP MODES
Deep Sleep modes are entered by:
• Setting the DSEN bit (DSCONH<7>)
• Executing the SLEEP instruction
To enter Retention Deep Sleep, the SRETEN bit must
also be set prior to setting the DSEN bit (Example 4-1).
In order to minimize the possibility of inadvertently
entering Deep Sleep, the DSEN bit must be set by two
separate write operations. To enter Deep Sleep, the
SLEEP instruction must be executed after setting the
DSEN bit (i.e., the next instruction). If DSEN is not set
when Sleep is executed, the device will enter a Sleep
mode instead.
4.4.3 DEEP SLEEP WAKE-UP SOURCES
The device can be awakened from Deep Sleep modes
by any of the following:
•MCLR
•POR
•RTCC Alarm
• INT0 Interrupt
• DSWDT Event
After waking from Deep Sleep mode, the device per-
forms a POR. When the device is released from Reset,
code execution will begin at the device’s Reset vector.
The software can determine if the wake-up was caused
from an exit from Deep Sleep mode by reading the
DPSLP bit (RCON4<2>). If this bit is set, the POR was
caused by a Deep Sleep exit. The DPSLP bit must be
manually cleared by the software.
The software can determine the wake-up event source
by reading the DSWAKE registers. These registers are
cleared automatically when entering Deep Sleep
mode, so software should read these registers after
exiting Deep Sleep mode or before re-enabling this
mode.
4.4.4 CLOCK SELECTION ON WAKE-UP
FROM DEEP SLEEP MODE
For Deep Sleep mode, the processor will restart with
the default oscillator source, selected with the FOSCx
Configuration bits. On wake-up from Deep Sleep, a
POR is generated internally, hence, the system resets
to its POR state with the exception of the RCONx,
DSCONH/L and DSGPRx registers.
For Retention Deep Sleep, the processor restarts with
the same clock source that was selected before enter-
ing Retention Deep Sleep mode. Wake-up is similar to
that of Sleep and Retention Sleep modes.
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4.4.5 SAVING CONTEXT DATA WITH THE
DSGPRx REGISTERS
As exiting Deep Sleep mode causes a POR, most
Special Function Registers (SFRs) reset to their default
POR values. In addition, because the core power is not
supplied in Deep Sleep mode, information in data RAM
may be lost when exiting this mode. Applications which
require critical data to be saved prior to Deep Sleep may
use the Deep Sleep General Purpose registers,
DSGPR0, DSGPR1, DSGPR2 and DSGPR3. Unlike
other SFRs, the contents of these registers are pre-
served while the device is in Deep Sleep mode. After
exiting Deep Sleep, software can restore the data by
reading the registers and clearing the RELEASE bit
(DSCONL<0>).
Any data stored in the DSGPRx registers must be writ-
ten twice. Like other Deep Sleep control features, the
write operations do not need to be sequential. However,
back-to-back writes are a recommended programming
practice.
Since the contents of data RAM are maintained in
Retention Deep Sleep, the use of the DSGPRx registers
to store critical data is not necessary in this mode.
4.4.6 I/O PINS DURING DEEP SLEEP
During Deep Sleep, general purpose I/O pins retain
their previous states. Pins that are configured as inputs
(TRIS bit is set), prior to entry into Deep Sleep, remain
high-impedance during Deep Sleep.
Pins that are configured as outputs (TRIS bit is clear),
prior to entry into Deep Sleep, will remain as output pins
during Deep Sleep. While in this mode, they will drive the
output level determined by their corresponding LAT bit at
the time of entry into Deep Sleep.
Once the device wakes back up, all I/O pins will continue
to maintain their previous states, even after the device
has finished the POR sequence and is executing applica-
tion code again. Pins configured as inputs during Deep
Sleep will remain high-impedance and pins configured as
outputs will continue to drive their previous value. After
waking up, the TRIS and LAT registers will be reset. If
firmware modifies the TRIS and LAT values for the I/O
pins, they will not immediately go to the newly configured
states. Once the firmware clears the RELEASE bit
(DSCONL<0>), the I/O pins are “released”. This
causes the I/O pins to take the states configured by
their respective TRIS and LAT bit values.
If the Deep Sleep BOR (DSBOR) is enabled, and a
DSBOR event occurs during Deep Sleep (or VDD is
hard-cycled to VSS), the I/O pins will be immediately
released, similar to clearing the RELEASE bit. All
previous state information will be lost, including the
general purpose DSGPR0, DSGPR1, DSGPR2 and
DSGPR3 contents. DSGPRx register contents will be
maintained if the VBAT pin is powered.
If a MCLR Reset event occurs during Deep Sleep, the
I/O pins will also be released automatically, but in this
case, the DSGPR0, DSGPR1, DSGPR2 and DSGPR3
contents will remain valid.
In case of MCLR Reset and all other Deep Sleep wake-up
cases, application firmware needs to clear the RELEASE
bit (DSCONL<0>) in order to reconfigure the I/O pins.
4.4.7 DEEP SLEEP WATCHDOG TIMER
(DSWDT)
Deep Sleep has its dedicated WDT (DSWDT). It is
enabled through the DSWDTEN Configuration bit. The
DSWDT is equipped with a postscaler for time-outs of
2.1 ms to 25.7 days, configurable through the Configura-
tion bits, DSWDTPS<4:0>. Entering Deep Sleep mode
automatically clears the DSWDT.
The DSWDT also has a configurable reference clock
source for selecting the LPRC or SOSC. The reference
clock source is configured through the DSWDTOSC
Configuration bit.
Under certain circumstances, it is possible for the DSWDT
clock source to be off when entering Deep Sleep mode. In
this case, the clock source is turned on automatically (if
DSWDT is enabled), without the need for software inter-
vention. However, this can cause a delay in the start of the
DSWDT counters. In order to avoid this delay, when using
SOSC as a clock source, the application can activate
SOSC prior to entering Deep Sleep mode.
4.4.8 DEEP SLEEP LOW-POWER
BROWN-OUT RESET
Devices with a Deep Sleep Power-Saving mode also
have a dedicated BOR for Deep Sleep modes (DSBOR).
It has a trip point range of 1.7V-2.3V nominal and is
enabled through the DSBOREN (CONFIG7L<3>)
Configuration bit.
When the device enters a Deep Sleep mode and
receives a DSBOR event, the device will not wake-up
and will remain in the Deep Sleep mode. When a valid
wake-up event occurs and causes the device to exit
Deep Sleep mode, software can determine if a DSBOR
event occurred during Deep Sleep mode by reading the
BOR (DSWAKEL<6>) status bit.
4.4.9 RTCC AND DEEP SLEEP
The RTCC can operate uninterrupted during Deep
Sleep modes. It can wake-up the device from Deep
Sleep by configuring an alarm. The RTCC clock source
is configured with the RTCC Clock Select bits,
RTCCLKSEL<1:0>. The available reference clock
sources are the LPRC and SOSC. If the LPRC is used,
the RTCC accuracy will directly depend on the LPRC
tolerance.
If the RTCC is not required, Deep Sleep mode with the
RTCC disabled, affords the lowest power consumption
of any of the instruction-based power-saving modes.
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4.4.10 CONTROL BIT SUMMARY FOR
SLEEP MODES
Table 4-5 shows the settings for the bits relevant to
Deep Sleep modes.
TABLE 4-5: BIT SETTINGS FOR ALL DEEP SLEEP MODES
4.4.11 WAKE-UP DELAYS
The Reset delays associated with wake-up from Deep
Sleep and Retention Deep Sleep modes, in different
oscillator modes, are provided in Table 4-6 and
Table 4-7, respectively.
TABLE 4-6: DELAY TIMES FOR EXITING FROM DEEP SLEEP MODE
Instruction-Based
Mode
DSEN
(DSCONH<7>)
Retention Regulator
DSWDTEN
(CONFIG8H<0>)
RETEN
(CONFIG7L<0>)
SRETEN
(RCON4<4>) State
Retention Deep Sleep 10 1Enabled 0
Deep Sleep 11 xDisabled x
Note: The PMSLP bit (RCON4<0>) allows the
voltage regulator to be maintained during
Sleep modes.
Clock Source Exit Delay Oscillator Delay Notes
EC TDSWU —
ECPLL TDSWU TLOCK 1, 3
MS, HS TDSWU TOST 1, 2
MSPLL, HSPLL TDSWU TOST + TLOCK 1, 2, 3
SOSC (Off during Sleep) TDSWU TOST 1, 2
(On during Sleep) TDSWU —1
FRC, FRCDIV TDSWU TFRC 1, 4
LPRC (Off during Sleep) TDSWU TLPRC 1, 4
(On during Sleep) TDSWU —1
FRCPLL TDSWU TFRC + TLOCK 1, 3, 4
Note 1: TDSWU = Deep Sleep wake-up delay.
2: T
OST = Oscillator Start-up Timer; a delay of 1024 oscillator periods before the oscillator clock is released to
the system.
3: TLOCK = PLL lock time.
4: TFRC and TLPRC are RC Oscillator start-up times.
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DS30575A-page 74 2012 Microchip Technology Inc.
TABLE 4-7: DELAY TIMES FOR EXITING RETENTION DEEP SLEEP MODE
Clock Source Exit Delay Oscillator Delay Notes
EC TRETR + TPM —1, 2, 6
ECPLL TRETR + TPM TLOCK 1, 2, 4, 6
MS, HS TRETR + TPM TOST 1, 2, 3, 6
MSPLL, HSPLL TRETR + TPM TOST + TLOCK 1, 2, 3, 4, 6
SOSC Off during Sleep TRETR + TPM TOST 1, 2, 3, 6
On during Sleep TRETR + TPM —1, 2, 6
FRC, FRCDIV TRETR + TPM TFRC 1, 2, 5, 6
LPRC: Off during Sleep TRETR + TPM TLPRC 1, 2, 5, 6
On during Sleep TRETR + TPM —1, 2, 6
FRCPLL TRETR + TPM TLOCK 1, 2, 3, 6
Note 1: TPM = Start-up delay for program memory stabilization; applicable only when IPEN (RCON<7>) = 0.
2: TRETR = Retention regulator start-up delay.
3: TOST = Oscillator Start-up Timer (OST); a delay of 1024 oscillator periods before the oscillator clock is
released to the system.
4: TLOCK = PLL lock time.
5: TFRC and TLPRC = RC Oscillator start-up times.
6: TFLASH = Flash program memory ready delay. Setting the PMSLP bit will provide a faster wake-up.
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4.5 VBAT Mode
VBAT mode is a hardware-based power mode that
maintains only the most critical operations when a
power loss occurs on VDD. The mode does this by
powering these systems from a back-up power source
connected to the VBAT pin. In this mode, the RTCC can
run even when there is no power on VDD.
VBAT mode is entered whenever power is removed
from VDD. An on-chip power switch detects the power
loss from the VDD and connects the VBAT pin to the
retention regulator. This provides power at 1.2V to
maintain the retention regulator, as well as the RTCC,
with its clock source (if enabled) and the Deep Sleep
General Purpose (DSGPRx) registers (Figure 4-1).
Entering VBAT mode requires that a power source, dis-
tinct from the main VDD power source, be available on
VBAT and that VDD be completely removed from the
VDD pin(s). Removing VDD can be either unintentional,
as in a power failure, or as part of a deliberate power
reduction strategy.
As with Deep Sleep modes, the contents of the Deep
Sleep General Purpose (DSGPRx) registers are main-
tained by the retention regulator. Since the power loss
on VDD may be unforeseen, it is recommended to load
any data to be saved in these registers in advance.
Any data stored in the DSGPRx registers must be written
twice. The write operations do not need to be sequential;
however, back-to-back writes are a recommended
programming practice.
FIGURE 4-1: VBAT POWER TOPOLOGY
Back-up
Battery
Power
Switch
Retention
Regulator
Core
Peripherals
DSGPRx
Registers
RTCC
1.2V
VBAT
VDD
VSS
PIC18F97J94 Family Microcontroller
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DS30575A-page 76 2012 Microchip Technology Inc.
4.5.1 WAKE-UP FROM VBAT MODES
When VDD is restored to a device in VBAT mode, it auto-
matically wakes. Wake-up occurs with a POR, after
which the device starts executing code from the Reset
vector. All SFRs, except the Deep Sleep semaphores
and RTCC registers are reset to their POR values. If
the RTCC was not configured to run during VBAT mode,
it will remain disabled and RTCC will not run. Wake-up
timing is similar to that for a normal POR.
Wake-up from VBAT mode is identified by checking the
state of the VBAT bit (RCON3<0>). If this bit is set
when the device is awake and starting to execute the
code from the Reset vector, it indicates that the exit
was from VBAT mode. To identify future VBAT wake-up
events, the bit must be cleared in software.
When a POR event occurs with no battery connected
to the VBAT pin, the VBPOR bit (RCON3<1>) becomes
set. On the device, if there is no battery connected to
the VBAT pin, VBPOR will indicate that the battery needs
to be connected to the VBAT pin.
In addition, if the VBAT power source falls below the
level needed for Deep Sleep semaphore operation
while in VBAT mode (e.g., the battery has been
drained), the VBPOR bit will be set. VBPOR is also set
when the microcontroller is powered up the very first
time, even if power is supplied to VBAT.
4.6 Saving Context Data with the
DSGPRx Registers
As exiting VBAT causes a POR, most Special Function
Registers reset to their default POR values. In addition,
because the core power is not supplied in VBAT mode,
information in data RAM will be lost when exiting this
mode. Applications which require critical data to be
saved, should be saved in DSGPR0, DSGPR1,
DSGPR2 and DSGPR3.
Any data stored to the DSGPRx registers must be
written twice. The write operations do not need to be
sequential. However, back-to-back writes are a
recommended programming practice.
After exiting VBAT mode, software can restore the data
by reading the registers.
4.6.1 I/O PINS DURING VBAT MODE
All I/O pins should be maintained at VSS level; no I/O
pins should be given VDD (refer to “Absolute
Maximum Ratings(†)” in Section 31.0 “Electrical
Characteristics”) during VBAT mode. The only
exceptions are the SOSCI and SOSCO pins, which
maintain their states if the Secondary Oscillator is
being used as the RTCC clock source. It is the user’s
responsibility to restore the I/O pins to their proper
states, using the TRIS and LAT bits, once VDD has
been restored.
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REGISTER 4-1: DSCONL: DEEP SLEEP CONTROL REGISTER LOW
REGISTER 4-2: DSCONH: DEEP SLEEP CONTROL REGISTER HIGH
U-0 U-0 U-0 U-0 U-0 R-0 R/W-0, HSC R/W-0, HS
— — — — — r DSBOR(1)RELEASE(1)
bit 7 bit 0
Legend: r = Reserved bit HSC = Hardware Settable/Clearable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
HS = Hardware Settable bit
bit 7-3 Unimplemented: Read as ‘0’
bit 2 Reserved: Maintained as ‘0’
bit 1 DSBOR: Deep Sleep BOR Event Status bit(1)
1 = DSBOR was enabled and VDD dropped below the DSBOR threshold during Deep Sleep(2)
0 = DSBOR disabled while device is in Deep Sleep mode
bit 0 RELEASE: I/O Pin State Release bit(1)
Upon waking from Deep Sleep, the I/O pins maintain their previous states. Clearing this bit will release
the I/O pins and allow their respective TRIS and LAT bits to control their states.
Note 1: This is the value when VDD is initially applied.
2: Unlike all other events, a Deep Sleep BOR event will not cause a wake-up from Deep Sleep; this bit is
present only as a status bit.
R/W-0 U-0 U-0 U-0 U-0 U-0 U-0 R/W-0, HS
(2)
DSEN
(
1
)
— — — — — —RTCCWDIS
bit 7 bit 0
Legend: HS = Hardware Settable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 DSEN: Deep Sleep Mode Enable bit(
1
)
1 = Deep Sleep mode is enabled and device will enter Deep Sleep mode when the SLEEP instruction
is executed
0 = Deep Sleep mode is not enabled
bit 6-1 Unimplemented: Read as ‘0’
bit 0 RTCCWDIS: RTCC Wake-up Disable bit
(2)
1 = Wake-up from RTCC is disabled
0 = Wake-up from RTCC is enabled
Note 1: In order to enter Deep Sleep, DSEN must be written to in two separate operations. The write operations
do not need to be consecutive. Before writing DSEN, the DSCON1 register should be cleared twice.
2: This is the value when VDD is initially applied.
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REGISTER 4-3: DSWAKEL: DEEP SLEEP WAKE-UP SOURCE REGISTER LOW(1)
REGISTER 4-4: DSWAKEH: DEEP SLEEP WAKE-UP SOURCE REGISTER HIGH
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
DSFLT BOR EXT DSWDT DSRTC MCLR ICD DSPOR
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 DSFLT: Deep Sleep Fault Detect bit
1 = A Deep Sleep Fault was detected during Deep Sleep
0 = A Deep Sleep Fault was not detected during Deep Sleep
bit 6 BOR: BOR Deep-Sleep Wake-up Source Enable bit
1 = DSBOR event will wake device from Deep Sleep
0 = DSBOR event will not wake device from Deep Sleep
bit 5 EXT: External Interrupt Wake-up Source Enable bit
1 = External interrupt will wake device from Deep Sleep
0 = External interrupt will not wake device from Deep Sleep
bit 4 DSWDT: DSWDT Deep-Sleep Wake-up Source Enable bit
1 = DSWDT roll-over event will wake device from Deep Sleep
0 = DSWDT roll-over event will not wake device from Deep Sleep
bit 3 DSRTC: Real-Time Clock and Calendar Alarm bit
1 = The Real-Time Clock/Calendar triggered an alarm during Deep Sleep
0 = The Real-Time Clock /Calendar did not trigger an alarm during Deep Sleep
bit 2 MCLR: MCLR Deep-Sleep Wake-up Source Enable bit
1 = The MCLR Reset will wake device from Deep Sleep
0 = The MCLR Reset will not wake device from Deep Sleep
bit 1 ICD: In-Circuit Debugger Deep-Sleep Wake-up Source Enable bit
1 = In-Circuit Debugger will wake device from Deep Sleep
0 = In-Circuit Debugger will not wake device from Deep Sleep
bit 0 DSPOR: Power-on Reset Event bit
1 = The VDD supply POR circuit was active and a POR event was detected
0 = The VDD supply POR circuit was not active, or was active but did not detect a POR event
Note 1: To be set in software, all bits in DSWAKE must be written to twice. The write operations do not need to be
consecutive.
U-0 U-0 U-0 U-0 U-0 U-0 U-0 R/W-0
— — — — — — —INT0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-1 Unimplemented: Read as ‘0’
bit 0 INT0: Deep Sleep Wake-up Source Enable bit
1 = INT0 interrupt will wake device from Deep Sleep
0 = INT0 interrupt will not wake device from Deep Sleep
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4.7 Selective Peripheral Power
Control
Sleep and Idle modes allow users to substantially reduce
power consumption by slowing or stopping the CPU
clock. Even so, peripheral modules still remain clocked,
and thus, consume some amount of power. There may
be cases where the application needs what these modes
do not provide: the ability to allocate limited power
resources to the CPU while eliminating power consump-
tion from the peripherals. The PIC18F97J94 family
addresses this requirement by allowing peripheral
modules to be selectively enabled or disabled, reducing
or eliminating their power consumption.
4.7.1 DISABLING PERIPHERAL
MODULES
Most of the peripheral modules in the
PIC18F97J94
family
architecture can be selectively disabled, reduc-
ing, or essentially eliminating, their power consumption
during all operating modes. Two different options are
available to users, each with a slightly different effect.
4.7.2 MODULE ENABLE BIT (XXXEN)
Many peripheral modules have a Module Enable bit,
generically named, “XXXEN”, usually located in Bit
Position 7 of their control registers (or Primary Control
registers for more complex modules). Here, “XXX”
represents the mnemonic form for the module of the
module name. For example, the enable bit for an
MSSPx module is “SSPEN”, and so on. The bit is pro-
vided for all serial and parallel communication modules
and the Real-Time Clock (RTC). Clearing this bit
disables the module’s operation; however, it continues
to receive clock signals and draw a minimal amount of
current.
As with all earlier PIC® MCU devices, timers continue to
be under selective operation and are controlled by their
own TON bit, also located in Position 7. The A/D Con-
verter also has a legacy enable bit, ADON, that has the
same function as the XXXEN bits. I/O ports and features
associated with them, such as input change notification
and input capture, do not have their own module enable
bits, since their operation is secondary to other modules.
Disabling modules not required for a particular applica-
tion, in this manner, allows for the selective and
dynamic adjusting power consumption, under software
control, as the application is running.
4.7.3 PERIPHERAL MODULE DISABLE
BIT (XXMD)
All peripheral modules (except for I/O ports) also have
a second control bit that can disable their functionality.
These bits, known as the Peripheral Module Disable
(PMD) bits, are generically named, “XXMD” (using “XX”
as the mnemonic version of the module’s name), as
shown in Section 4.7.2 “Module Enable Bit
(XXXEN)”). These bits are located in the PMDx SFRs.
In contrast to the module enable bits, the XXMD bit
must be set (= 1) to disable the module.
While the PMD and module enable bits both disable a
peripheral’s functionality, the PMD bit completely shuts
down the peripheral, effectively powering down all
circuits and removing all clock sources. This has the
additional effect of making any of the module’s control
and buffer registers, mapped in the SFR space,
unavailable for operations. In other words, when the
PMD bit is used to disable a module, the peripheral
ceases to exist until the PMD bit is cleared. This differs
from using the module enable bit, which allows the
peripheral to be reconfigured and buffer registers
preloaded, even when the peripheral’s operations are
disabled.
The PMD bit is most useful in highly power-sensitive
applications, where even tiny savings in power
consumption can determine the ability of an application
to function. In these cases, the bits can be set before
the main body of the application to remove those
peripherals that will not be needed at all.
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REGISTER 4-5: PMD0: PERIPHERAL MODULE DISABLE REGISTER 0
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CCP10MD CCP9MD CCP8MD CCP7MD CCP6MD CCP5MD CCP4MD ECCP3MD
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CCP10MD: CCP10 Module Disable bit
1 = The CCP10 module is disabled. All CCP10 registers are held in Reset and are not writable.
0 = The CCP10 module is enable
bit 6 CCP9MD: CCP9 Module Disable bit
1 = The CCP9 module is disabled. All CCP9 registers are held in Reset and are not writable.
0 = The CCP9 module is enabled
bit 5 CCP8MD: CCP8 Module Disable bit
1 = The CCP8 module is disabled. All CCP8 registers are held in Reset and are not writable.
0 = The CCP8 module is enabled
bit 4 CCP7MD: CCP7 Module Disable bit
1 = The CCP7 module is disabled. All CCP7 registers are held in Reset and are not writable.
0 = The CCP7 module is enabled
bit 3 CCP6MD: CCP6 Module Disable bit
1 = The CCP6 module is disabled. All CCP6 registers are held in Reset and are not writable.
0 = The CCP6 module is enabled
bit 2 CCP5MD: CCP5 Module Disable bit
1 = The CCP5 module is disabled. All CCP5 registers are held in Reset and are not writable.
0 = The CCP5 module is enabled
bit 1 CCP4MD: CCP4 Module Disable bit
1 = The CCP4 module is disabled. All CCP4 registers are held in Reset and are not writable.
0 = The CCP4 module is enabled
bit 0 ECCP3MD: ECCP3 Module Disable bit
1 = The ECCP3 module is disabled. All ECCP3 registers are held in Reset and are not writable.
0 = The ECCP3 module is enabled
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REGISTER 4-6: PMD1: PERIPHERAL MODULE DISABLE REGISTER 1
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ECCP2MD ECCP1MD UART4MD UART3MD UART2MD UART1MD SSP2MD SSP1MD
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ECCP2MD: ECCP2 Module Disable bit
1 = The ECCP2 module is disabled. All ECCP2 registers are held in Reset and are not writable.
0 = The ECCP2 module is enabled
bit 6 ECCP1MD: ECCP1 Module Disable bit
1 = The ECCP1 module is disabled. All ECCP1 registers are held in Reset and are not writable.
0 = The ECCP1 module is enabled
bit 5 UART4MD: USART4 Module Disable bit
1 = The USART4 module is disabled. All USART4 registers are held in Reset and are not writable.
0 = The USART4 module is enabled
bit 4 UART3MD: USART3 Module Disable bit
1 = The USART3 module is disabled. All USART3 registers are held in Reset and are not writable.
0 = The USART3 module is enabled
bit 3 UART2MD: USART2 Module Disable bit
1 = The USART2 module is disabled. All USART2 registers are held in Reset and are not writable.
0 = The USART2 module is enabled
bit 2 UART1MD: USART1 Module Disable bit
1 = The USART1 module is disabled. All USART1 registers are held in Reset and are not writable.
0 = The USART1 module is enabled
bit 1 SSP2MD: SSP2 Module Disable bit
1 = The SSP2 module is disabled. All SSP2 registers are held in Reset and are not writable.
0 = The SSP2 module is enabled
bit 0 SSP1MD: SSP1 Module Disable bit
1 = The SSP1 module is disabled. All SSP1 registers are held in Reset and are not writable.
0 = The SSP1 module is enabled
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REGISTER 4-7: PMD2: PERIPHERAL MODULE DISABLE REGISTER 2
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
TMR8MD TMR6MD TMR5MD TMR4MD TMR3MD TMR2MD TMR1MD TMR0MD
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 TMR8MD: Timer8 Module Disable bit
1 = The Timer8 module is disabled. All Timer8 registers are held in Reset and are not writable.
0 = The Timer8 module is enabled
bit 6 TMR6MD: Timer6 Module Disable bit
1 = The Timer6 module is disabled. All Timer6 registers are held in Reset and are not writable.
0 = The Timer6 module is enabled
bit 5 TMR5MD: Timer5 Module Disable bit
1 = The Timer5 module is disabled. All Timer5 registers are held in Reset and are not writable.
0 = The Timer5 module is enabled
bit 4 TMR4MD: Timer4 Module Disable bit
1 = The Timer4 module is disabled. All Timer4 registers are held in Reset and are not writable.
0 = The Timer4 module is enabled
bit 3 TMR3MD: Timer3 Module Disable bit
1 = The Timer3 module is disabled. All Timer3 registers are held in Reset and are not writable.
0 = The Timer3 module is enabled
bit 2 TMR2MD: Timer2 Module Disable bit
1 = The Timer2 module is disabled. All Timer2 registers are held in Reset and are not writable.
0 = The Timer2 module is enabled
bit 1 TMR1MD: Timer1 Module Disable bit
1 = The Timer1 module is disabled. All Timer1 registers are held in Reset and are not writable.
0 = The Timer1 module is enabled
bit 0 TMR0MD: Timer0 Module Disable bit
1 = The Timer0 module is disabled. All Timer0 registers are held in Reset and are not writable.
0 = The Timer0 module is enabled
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REGISTER 4-8: PMD3: PERIPHERAL MODULE DISABLE REGISTER 3
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
TXMMD CTMUMD ADCMD RTCCMD LCDMD PSPMD REFO1MD REFO2MD
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 TXMMD: Modulator Output Module Disable bit
1 = The Modulator Output module is disabled. All Modulator Output registers are held in Reset and
are not writable.
0 = The Modulator Output module is enabled
bit 6 CTMUMD: CTMU Module Disable bit
1 =The CTMU module is disabled. All CTMU registers are held in Reset and are not writable.
0 =The CTMU module is enabled
bit 5 ADCMD: ADC Module Disable bit
1 =The ADC module is disabled. All ADC registers are held in Reset and are not writable.
0 =The ADC module is enabled
bit 4 RTCCMD: RTCC Module Disable bit
1 = The RTCC module is disabled. All RTCC registers are held in Reset and are not writable.
0 = The RTCC module is enabled
bit 3 LCDMD: LCD Module Disable bit
1 = The LCD module is disabled. All LCD registers are held in Reset and are not writable.
0 = The LCD module is enabled
bit 2 PSPMD: PSP Module Disable bit
1 = The PSP module is disabled. All PSP registers are held in Reset and not are writable.
0 = The PSP module is enabled
bit 1 REFO1MD: REFO1 Module Disable bit
1 = The REFO1 module is disabled. All REFO1 registers are held in Reset and are not writable.
0 = The REFO1 module is enabled
bit 0 REFO2MD: REFO2 Module Disable bit
1 = The REFO2 module is disabled. All REFO2 registers are held in Reset and are not writable.
0 = The REFO2 module is enabled
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REGISTER 4-9: PMD4: PERIPHERAL MODULE DISABLE REGISTER 4
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0
CMP1MD CMP2MD CMP3MD USBMD IOCMD LVDMD —EMBMD
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CMP1MD: CMP1 Module Disable bit
1 = The CMP1 module is disabled; all CMP1 registers are held in Reset and are not writable
0 = The CMP1 module is enabled
bit 6 CMP2MD: CMP2 Module Disable bit
1 = The CMP2 module is disabled; all CMP2 registers are held in Reset and are not writable
0 = The CMP2 module is enabled
bit 5 CMP3MD: CMP3 Module Disable bit
1 = The CMP3 module is disabled; all CMP3 registers are held in Reset and are not writable
0 = The CMP3 module is enabled
bit 4 USBMD: USB Module Disable bit
1 = The USB module is disabled; all USB registers are held in Reset and are not writable
0 = The USB module is enabled
bit 3 IOCMD: Interrupt-on-Change Module Disable bit
1 = The IOC module is disabled; all IOC registers are held in Reset and are not writable
0 = The IOC module is enabled
bit 2 LVDMD: Low Voltage Detect Module Disable bit
1 = The LVD module is disabled; all LVD registers are held in Reset and are not writable
0 = The LVD module is enabled
bit 1 Unimplemented: Read as ‘0’
bit 0 EMBMD: EMB Module Disable bit
1 = The EMB module is disabled; all EMB registers are held in Reset and are not writable
0 = The EMB module is enabled
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5.0 RESET
The PIC18F97J94 family devices differentiate between
various kinds of Reset:
a) Power-on Reset (POR)
b) MCLR Reset
c) Watchdog Timer (WDT) Reset
d) Configuration Mismatch (CM)
e) Brown-out Reset (BOR)
f) RESET Instruction
g) Stack Underflow/Overflow Reset
This section discusses Resets generated by MCLR,
POR and BOR, and covers the operation of the various
start-up timers. For information on WDT Resets, see
Section 28.2 “Watchdog Timer (WDT)”. For Stack
Reset events, see Section 6.1.4.4 “Stack Full and
Underflow Resets”. For Deep Sleep mode, see
Section 4.4 “Deep Sleep Modes”.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 5-1.
5.1 RCON Registers
Device Reset events are tracked through the RCON,
RCON2, RCON3 and RCON4 registers (Register 5-1,
Register 5-2, Register 5-3 and Register 5-4). The regis-
ter bits indicate that a specific Reset event has occurred.
Depending on the definition, status bits may be set or
cleared by the event, and re-initialized by the applica-
tion, after the event to the opposite state. Setting or
clearing Reset status bits does not cause a Reset.
The state of these flag bits, taken together, can be read
to indicate the type of Reset that just occurred.
The RCON register also has a control bit for setting
interrupt priority (IPEN). Interrupt priority is discussed
in Section 10.0 “Interrupts”.
FIGURE 5-1: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
External Reset
MCLR
VDD
OSC1
VDD Rise
Detect
OST/PWRT
INTOSC
(1)
POR Pulse
OST
10-Bit Ripple Counter
PWRT
Internal Reset
11-Bit Ripple Counter
Enable OST(2)
Enable PWRT
Note 1: This is the INTOSC source from the internal oscillator block and is separate from the RC Oscillator of the CLKI pin.
2: See Table 5-1 for time-out situations.
Brown-out
Reset
BOREN
RESET
Instruction
Stack
Pointer
Stack Full/Underflow Reset
Sleep
Idle
1024 Cycles
1 ms
32 s
MCLRE
WDT
Time-out
S
RQ
PIC18F97J94 FAMILY
DS30575A-page 86 2012 Microchip Technology Inc.
REGISTER 5-1: RCON: RESET CONTROL REGISTER
R/W-0 U-0 R/W-1 R/W-1 R-1 R-1 R/W-0(1)R/W-0
IPEN —CMRI TO PD POR BOR
bit 7 bit 0
Legend: HC = Hardware Clearable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 IPEN: Interrupt Priority Enable Register bit
1 = Prioritized interrupts are enabled
0 = Prioritized interrupts are disabled
bit 6 Unimplemented: Read as ‘0’
bit 5 CM: Configuration Mismatch Flag bit
1 = A Configuration Mismatch Reset has not occurred
0 = A Configuration Mismatch Reset occurred; must be set in software once the Reset occurs
bit 4 RI: RESET Instruction Flag bit
1 = The RESET instruction was not executed (set by firmware only)
0 = The RESET instruction was executed, causing a device Reset (must be set in software after a
Brown-out Reset occurs)
bit 3 TO: Watchdog Time-out Flag bit
1 = Set by power-up, CLRWDT instruction or SLEEP instruction
0 = A WDT time-out occurred
bit 2 PD: Power-down Detection Flag bit
1 = Set by power-up or by the CLRWDT instruction
0 = Set by execution of the SLEEP instruction
bit 1 POR: Power-on Reset Status bit(1)
1 = A Power-on Reset has not occurred (set by firmware only)
0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs)
bit 0 BOR: Brown-out Reset Status bit
1 = A Brown-out Reset has not occurred (set by firmware only)
0 = A Brown-out Reset occurred (must be set in software after a Brown-out Reset occurs)
Note 1: Brown-out Reset is said to have occurred when BOR is ‘0’ and POR is ‘1’ (assuming that POR was set to
‘1’ by software immediately after a Power-on Reset).
2012 Microchip Technology Inc. DS30575A-page 87
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REGISTER 5-2: RCON2: RESET CONTROL REGISTER 2
R/W-0, HS U-0 R/W-0 U-0 U-0 U-0 U-0 U-0
EXTR(1)—SWDTEN
(2)— — — — —
bit 7 bit 0
Legend: HS = Hardware Settable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 EXTR: External Reset (MCLR) Pin bit(1)
1 = A Master Clear (pin) Reset has occurred
0 = A Master Clear (pin) Reset has not occurred
bit 6 Unimplemented: Read as ‘0’
bit 5 SWDTEN: Software Controlled Watchdog Timer Enable bit(2)
1 = Watchdog Timer is on
0 = Watchdog Timer is off
bit 4-0 Unimplemented: Read as ‘0’
Note 1: This bit is set in hardware; it can be cleared in software.
2: This bit has no effect unless the Configuration bits, WDTEN<1:0> = 10.
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DS30575A-page 88 2012 Microchip Technology Inc.
REGISTER 5-3: RCON3: RESET CONTROL REGISTER 3
U-0 U-0 U-0 U-0 R/C-0 R/C-0 R/C-0 R/W-0
— — — — VDDBOR(1)VDDPOR(1,2)VBPOR(1,3)VBAT
bit 7 bit 0
Legend: C = Clearable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 Unimplemented: Read as ‘0’
bit 3 VDDBOR: VDD Brown-out Reset Flag bit(1)
1 =A VDD Brown-out Reset has occurred
0 =A V
DD Brown-out Reset has not occurred
bit 2 VDDPOR: VDD Power-On Reset Flag bit(1,2)
1 =A VDD Power-up Reset has occurred
0 =A V
DD Power-up Reset has not occurred
bit 1 VBPOR: VBPOR Flag bit(1,3)
1 =A VBAT POR has occurred
0 =A V
BAT POR has not occurred
bit 0 VBAT: VBAT Flag bit(1)
1 = A POR exit has occurred while power was applied to VBAT pin
0 = A POR exit from VBAT has not occurred
Note 1: This bit is set in hardware only; it can only be cleared in software.
2: Indicates a VDD POR. Setting the POR bit (RCON<0>) indicates a VCORE POR.
3: This bit is set when the device is originally powered up, even if power is present on VBAT.
2012 Microchip Technology Inc. DS30575A-page 89
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REGISTER 5-4: RCON4: RESET CONTROL REGISTER 4
U-0 U-0 U-0 R/W-0 U-0 R/C-0 U-0 R/W-0
— — — SRETEN(1)—DPSLP(2)—PMSLP
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘0’
bit 4 SRETEN: Retention Regulator Voltage Sleep Disable bit(1)
1 = If RETEN (CONFIG7L<0>) = 0 and the regulator is enabled, the device goes into Retention mode
in Sleep
0 = The regulator is on when device’s Sleep mode is enabled and the Low-Power mode is controlled
by the PMSLP bit
bit 3 Unimplemented: Read as ‘0’
bit 2 DPSLP: Deep Sleep Wake-up Status bit (used in conjunction with the POR and BOR bits in RCON to
determine the Reset source)(2)
1 = The last exit from Reset was caused by a normal wake-up from Deep Sleep
0 = The last exit from Reset was not due to a wake-up from Deep Sleep
bit 1 Unimplemented: Read as ‘0’
bit 0 PMSLP: Program Memory Power During Sleep bit
1 = Program memory bias voltage remains powered during Sleep
0 = Program memory bias voltage is powered down during Sleep
Note 1: This bit is available only when RETEN (CONFIG7L<0>) = 0.
2: This bit is set in hardware only; it can only be cleared in software.
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5.2 Power-on Reset (POR)
The PIC18F97J94 family has two types of Power-on
Resets:
•POR
•V
BAT POR
POR is the legacy PIC18J series Power-on Reset which
monitors core power supply. The second, VBAT POR,
monitors voltage on the VBAT pin. These POR circuits
use the same technique to enable and monitor their
respective power source for adequate voltage levels to
ensure proper chip operation. There are two threshold
voltages associated with them. The first voltage is the
device threshold voltage, VPOR. The device threshold
voltage is the voltage at which the POR module
becomes operable. The second voltage associated with
a POR event is the POR circuit threshold voltage. Once
the correct threshold voltage is detected, a power-on
event occurs and the POR module hibernates to
minimize current consumption.
A power-on event generates an internal POR pulse
when a VDD rise is detected. The device supply voltage
characteristics must meet the specified starting voltage,
VPOR, and rise rate requirements, SVDD, to generate the
POR pulse. In particular, VDD must fall below VPOR
before a new POR is initiated. For more information on
the VPOR and VDD rise rate specifications, refer to
Section 31.0 “Electrical Characteristics”.
5.2.1 POR CIRCUIT
The POR circuit behaves differently than VBAT POR
once the POR state becomes active. The internal POR
pulse resets the POR timer and places the device in the
Reset state. The POR also selects the device clock
source identified by the Oscillator Configuration bits.
After the POR pulse is generated, the POR circuit
inserts a small delay, TCSD, to ensure that internal
device bias circuits are stable.
After the expiration of TCSD, a delay, TPWRT, is always
inserted every time the device resumes operation after
any power-down. During this time, code execution is
disabled. The PWRT is used to extend the duration of
a power-up sequence to permit the on-chip band gap
and regulator to stabilize and to load the Configuration
Word settings. The on-chip regulator is always enabled
and its stabilization time is shorter than other concur-
rently running delays, and does not extend start-up
time.
The power-on event clears the BOR and POR status
bits (RCON<1:0>); it does not change for any other
Reset event. POR is not reset to ‘1’ by any hardware
event. To capture multiple events, the user manually
resets the bit to ‘1’ in software following any Power-on
Reset. Alternatively, the VDDPOR (RCON3<2>) bit can
be used; it is set on a VDD POR event. It must be
cleared after any Power-on Reset to detect subsequent
VDD POR events.
After TPWRT expires, an additional start-up time for the
system clock (either TOST, TIOBST and TRC, depending
on the source) occurs while the clock source becomes
stable. Internal Reset is then released and the device
is no longer held in Reset (Ta b l e 5 - 2 ). Once all of the
delays have expired, the system clock is released and
code execution can begin. Refer to Section 31.0
“Electrical Characteristics” for more information on
the values of the delay parameters.
Note: When the device exits the Reset condition
(begins normal operation), the device
operating parameters (voltage, frequency,
temperature, etc.) must be within their
operating ranges; otherwise, the device
will not function correctly. The user must
ensure that the delay between the time
power is first applied, and the time,
INTERNAL RESET, becomes inactive, is
long enough to get all operating
parameters within specification.
2012 Microchip Technology Inc. DS30575A-page 91
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FIGURE 5-2: POR MODULE TIMING SEQUENCE FOR RISING VDD
TCSD
VDD VPOR
POR Circuit Threshold Voltage
SYSRST
TPWRT
Internal Power-on Reset Pulse Occurs
and Begins POR Delay Time, TCSD
POR Circuit is Initialized at VPOR
Time
System Clock is Started
After TPWRT Delay
Expires
System Clock is Released
and Code Execution
Begins
POR
PWRT
Note 1: Timer and interval are determined by the initial start-up oscillator configuration; TOSC is for external
oscillator modes, TFRC is for the FRC Oscillator or TLPRC for the internal 31 kHz RC Oscillator.
(Note 1)
INTERNAL RESET
System Reset is Released
After Clock is Stable
Oscillator Delay
and Code Execution
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DS30575A-page 92 2012 Microchip Technology Inc.
5.2.1.1 Using the POR Circuit
To take advantage of the POR circuit, tie the MCLR pin
directly to VDD. This will eliminate external RC compo-
nents usually needed to create a POR delay. A
minimum rise time for VDD is required. Refer to the
“Electrical Characteristics” section of the specific
device data sheet for more information.
Depending on the application, a resistor may be
required between the MCLR pin and VDD. This resistor
can be used to decouple the MCLR pin from a noisy
power supply rail.
Figure 5-3 displays a possible POR circuit for a slow
power supply ramp up. The external POR circuit is only
required if the device would exit Reset before the
device VDD is in the valid operating range. The diode,
D, helps discharge the capacitor quickly when VDD
powers down.
FIGURE 5-3: EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW VDD POWER-UP)
5.2.2 VBAT POWER-ON-RESET (VBPOR)
The device will remain in VBAT mode as long as no
power is present on VDD. The VBPOR is active when
the device is operating in VBAT mode and deriving
power from the VBAT pin. Similar to the POR, the circuit
monitors VBAT voltage and holds the device in Reset
until adequate voltage is present to power up the
device. After exiting the VBAT POR condition, the
VBPOR (RCON3<1>) bit is set. All other registers will
be in a POR state, including Deep Sleep semaphores.
Minimum VBAT ramp time and rearm voltage require-
ments apply. Refer to Parameters D003 and D004 in
Section 31.0 “Electrical Characteristics” for details.
The device does not execute code in VBAT mode. Also,
there is no Power-up Timer associated with VBPOR.
After VDD power is restored, the device exits VBAT
mode and the VBAT (RCON3<0>) bit is set. All other
registers, except those associated with RTCC, its clock
source and the Deep Sleep semaphores (DSGPRx),
will be in a POR state. For more information about VBAT
mode, see Section 4.5 “Vbat Mode”.
5.3 Master Clear Reset (MCLR)
Whenever the MCLR pin is driven low, the device asyn-
chronously asserts SYSRST, provided the input pulse
on MCLR is longer than a certain minimum width, TMCL
(see Section 31.0 “Electrical Characteristics”).
When the MCLR pin is released, SYSRST is also
released. The Reset vector fetch starts from the
SYSRST release. The processor continues to use the
existing clock source that was in use before the MCLR
Reset occurred. The EXTR status bit (RCON2<7>) is
set to indicate the MCLR Reset.
5.4 Watchdog Timer Reset (WDT)
Whenever a Watchdog Timer time-out occurs, the
device asynchronously asserts SYSRST
. The clock
source remains unchanged. Note that a WDT time-out
during Sleep or Idle mode will wake-up the processor,
but NOT reset the processor. The TO bit (RCON<3>) is
cleared when a WDT time-out occurs. Software must
set this bit to initialize the flag. For more information,
refer to Section 28.2 “Watchdog Timer (WDT)”.
Note 1: External Power-on Reset circuit is required
only if the VDD power-up slope is too slow.
The diode, D, helps discharge the capacitor
quickly when VDD powers down.
2: R < 40 k is recommended to make sure that
the voltage drop across R does not violate
the device’s electrical specification.
3: R1 1 k will limit any current flowing into
MCLR from external capacitor, C, in the event
of MCLR/VPP pin breakdown, due to Electro-
static Discharge (ESD) or Electrical
Overstress (EOS).
C
R1
R
D
VDD
MCLR
PIC18FXXJXX
VDD
Note: The WDT described here is not the same
one used in Deep Sleep mode. For more
information on Deep Sleep WDT, see
Section 28.2 “Watchdog Timer (WDT)”.
2012 Microchip Technology Inc. DS30575A-page 93
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5.5 Configuration Mismatch
Reset (CM)
The Configuration Mismatch (CM) Reset is designed to
detect, and attempt to recover from, random memory
corrupting events. These include Electrostatic
Discharge (ESD) events, which can cause widespread,
single bit changes throughout the device and result in
catastrophic failure.
In PIC18FXXJXX Flash devices, device Configuration
registers (located in the configuration memory space)
are continuously monitored during operation by compar-
ing their values to complimentary shadow registers. If a
mismatch is detected between the two sets of registers,
a CM Reset automatically occurs. These events are
captured by the CM bit (RCON<5>) being set to ‘0’.
This bit does not change for any other Reset event. A
CM Reset behaves similarly to a Master Clear Reset,
RESET instruction, WDT Time-out Reset or Stack Event
Reset. As with all hard and power Reset events, the
device’s Configuration Words are reloaded from the
Flash Configuration Words in program memory as the
device restarts.
5.6 Brown-out Reset (BOR) Features
The PIC97J94 family has four different types of BOR
circuits:
• Brown-out Reset (BOR)
•V
DDCORE Brown-out Reset (VDDBOR)
•V
BAT Brown-out Reset (VBATBOR)
• Deep Sleep Brown-out Reset (DSBOR)
All four BOR circuits monitor a voltage and put the
device in a Reset condition while the voltage is in a
specified region. SFRs will reset to the BOR state,
including the Deep Sleep semaphore holding registers,
DSGPR0 and DSGPR1. Upon BOR exit, the device
remains in Reset until the associated trip point voltage
is exceeded. Any I/O pins configured as outputs will be
tri-stated. BOR, VDDBOR and DSBOR exit into Run
mode; VBATBOR remains in VBAT mode.
These features differ by their power mode, monitored
voltage source, trip points, control and status. Refer to
Table 5-1 for the PIC18F97J94 BOR differences.
TABLE 5-1: BOR FEATURE SUMMARY(1)
Feature Mode Source Trip Points Enable
BOR Run, Idle, Sleep VDDCORE 1.6V (typ) Always Enabled
VDDBOR Run, Idle, Sleep VDD VVDDBOR BOREN (CONFIG1H<0>)
VBATBOR VBAT VBAT VVBATBOR VBTBOR (CONFIG7L<2>)
DSBOR Deep Sleep VDD VDSBOR DSBOREN (CONFIG7L<3>)
Note 1: Refer to Table 31-9 for details.
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DS30575A-page 94 2012 Microchip Technology Inc.
5.6.1 BROWN-OUT RESET (BOR)
Brown-out Reset is the legacy PIC18 “J” feature that
monitors the core voltage, VDDCORE. Since the regulator
on the PIC18F97J94 family is always enabled, this
feature is always active. Its trip point is non-configurable.
A Brown-out Reset will occur as the regulator output
voltage drops below, approximately 1.6V. After proper
operating voltage recovers, the Brown-out Reset condi-
tion is exited and execution begins after the Power-up
Timer has expired. The BOR (RCON<0>) bit is also
cleared. This bit must be set after each Brown-out and
Power-on Reset event to detect subsequent Brown-out
Reset events.
5.6.2 VDD BOR (VDDBOR)
VDDBOR is enabled by setting the BOREN
(CONFIG1H<0>) Configuration bit. The low-power
BOR trip level is configurable to either 1.8V or 2.0V,
(typ) depending on the BORV (CONFIG1H<1>) Config-
uration bit setting. When in normal Run mode, Idle or
normal Sleep modes, the BOR circuit that monitors
VDD is active and will cause the device to be held in
BOR if VDD drops below VBOR. Once VDD rises back
above VVDDBOR, the device will be held in Reset until
the expiration of the Power-up Timer, with period,
TPWRT. This event is captured by the VDDBOR flag bit
(RCON3<3>).
5.6.3 DETECTING VDD BOR
When the BOR module is enabled, the VDDBOR
(RCON3<3>) bit is set on a Brown-out Reset event. This
makes it difficult to determine if a Brown-out Reset event
has occurred just by reading the state of VDDBOR
alone. A more reliable method is to simultaneously
check the state of both VDDPOR and VDDBOR. This
assumes that the VDDPOR bit is reset to ‘1’ in software
immediately after any Power-on Reset event. If
VDDBOR is ‘0’ while VDDPOR is ‘1’, it can be reliably
assumed that a Brown-out Reset event has occurred.
Legacy PIC18 software can use the respective POR
(RCON<1>) and BOR (RCON<0>) bits. This technique
monitors the regulator output voltage, VDDCORE. To take
advantage of the configuration features, it is
recommended to use VDDBOR instead of BOR.
5.6.4 VBAT BROWN-OUT RESET
(VBATBOR)
The VBAT BOR can be enabled/disabled using the
VBTBOR bit in the Configuration register
(CONFIG7L<2>). If the VBTBOR enable bit is cleared,
the VBATBOR is always disabled and there will be no
indication of a VBAT BOR. If the VBTBOR bit is set, the
VBAT POR will reset the device when the battery volt-
age drops below VVBATBOR. After power is restored to
the VBAT pin, the device exits Reset and returns to
VBAT mode. The device remains in VBAT mode until
power returns to the VDD pin. For more information on
using the VBAT feature, refer to Section 4.5 “Vbat
Mode”.
5.6.5 DEEP SLEEP BROWN-OUT RESET
(DSBOR)
The PIC18F97J94 has its dedicated BOR for Deep
Sleep mode (DSBOR). It is enabled through the
DSBOREN (CONFIG7L<3>) Configuration bit. When
the device enters Deep Sleep mode and receives a
DSBOR event, the device will not wake-up and will
remain in Deep Sleep mode. When a valid wake-up
event occurs and causes the device to exit Deep Sleep
mode, software can determine if a DSBOR event
occurred during Deep Sleep mode by reading the
DSBOR (DSCONL<1>) status bit.
5.7 RESET Instruction
Whenever the RESET instruction is executed, the
device asserts SYSRST
. This Reset state does not
re-initialize the clock. The clock source that is in effect
prior to the RESET instruction remains in effect. Config-
uration settings are updated and the SYSRST is
released at the next instruction cycle. A noise filter in
the MCLR Reset path detects and ignores small
pulses. The RI bit (RCON<4>) is cleared when a
RESET instruction is executed. Software must set this
bit to initialize the flag.
5.8 Stack Underflow/Overflow Reset
A Reset can be enabled on stack error conditions by
setting the STVREN (CONFIG1L<5>) Configuration
bit. See Section 6.1.4.4 “Stack Full and Underflow
Resets”section for additional information.
Note: Brown-out Reset (BOR) has been pro-
vided to support legacy devices that can
disable their internal regulator. The
PIC18F97J94 family’s regulator is always
enabled. Therefore, it’s recommended
that new designs use VDDBOR to detect
Brown-out conditions.
2012 Microchip Technology Inc. DS30575A-page 95
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5.9 Device Reset Timers
PIC18F97J94 family devices incorporate three sepa-
rate on-chip timers that help regulate the Power-on
Reset process. Their main function is to ensure that the
device clock is stable before code is executed. These
timers are:
• Power-up Timer (PWRT)
• Oscillator Start-up Timer (OST)
• PLL Lock Time-out
5.9.1 POWER-UP TIMER (PWRT)
The Power-up Timer (PWRT) of the PIC18F97J94 fam-
ily devices is a counter which uses the INTOSC source
as the clock input. While the PWRT is counting, the
device is held in Reset. The power-up time delay
depends on the INTOSC clock and varies slightly from
chip-to-chip due to temperature and process variation.
See the TPWRT specification for details. The PWRT is
always enabled and active after Brown-out and
Power-on Reset events.
5.9.2 OSCILLATOR START-UP TIMER
(OST)
The Oscillator Start-up Timer (OST) provides a
1024 oscillator cycle (from OSC1 input) delay after the
PWRT delay is over. This ensures that the crystal
oscillator or resonator has started and stabilized.
The OST time-out is invoked only for LP, MS, HS and
HSPLL modes, and only on Power-on Reset or on exit
from most power-managed modes.
5.9.3 PLL LOCK TIME-OUT
The PLL is enabled by programming FOSC<2:0> = 011
(CONFIG2L<2:0>. With the PLL enabled, the time-out
sequence, following a Power-on Reset, is slightly differ-
ent from other oscillator modes. A separate timer is used
to provide a fixed time-out that is sufficient for the PLL to
lock to the main oscillator frequency. This PLL lock
time-out (TRC) follows the oscillator start-up time-out.
5.9.4 RESET STATE OF REGISTERS
Most registers are unaffected by a Reset. Their status
is unknown on a Power-on Reset and unchanged by all
other Resets. The other registers are forced to a “Reset
state” depending on the type of Reset that occurred.
Most registers are not affected by a WDT wake-up,
since this is viewed as the resumption of normal oper-
ation. Status bits from the RCONx registers are set or
cleared differently in different Reset situations, as
indicated in Ta b l e 5 - 2 . These bits are used in software
to determine the nature of the Reset.
Table 5-2 describes the Reset states for all of the
Special Function Registers. These are categorized by
Power-on and Brown-out Resets, Master Clear and
WDT Resets, and WDT wake-ups.
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TABLE 5-2: RCONx BIT OPERATION ON VARIOUS RESETS AND WAKE-UPS
Conditions
PC
DPSLP
EXTR
RI
TO
PD
IDLE
CM
BOR
POR
VDDBOR
VDDPOR
VBPOR(4,6)
VBAT(4)
DSPOR:(4)
Loss of VDDBAT
000000 0 0 0 0 1 0 0 1 1 1 1 1 0
VBAT:(4)
Loss of VDD While VBAT is Established
000000 1 0 0 0 1 0 0 1 1 1 1 u1
VDD POR:
Loss of VDD
000000 0 0 0 0 1 0 0 1 1 1 1 uu
VDD BOR:
Brown-out of VDD
000000 uu00 1 0 0uu1uuu
POR:
Loss of VDDCORE
000000 0 0 0 0 1 0 0 1 1 uuu u
BOR
Brown-out of VDDCORE
000000 uu00 1 0 01 uuuuu
Deep Sleep Exit 000000 1 0 0 0 1 0 0 1 1 uuu u
Retention Deep Sleep Exit 000000 1 0 0 0 1 0 0 0 0 uuu u
MCLR Reset
Operational Mode
000000 u1uu u uuuuuuuu
MCLR Reset in Idle Mode 000000 u1u0(1) 0(2) 1(2) uuuuuuu
MCLR Reset in Sleep Mode 000000 u1u0(1) 0(2) 0(2) uuuuuuu
RESET Instruction Reset 000000 uu1u u uuuuuuuu
Configuration Mismatch Reset 000000 uuuuuu1uuuu u u
WDT Reset 000000 uuu 1u uuuuuuuu
WDT Reset in Idle Mode PC + 2 u u u 11
(2) 1(2)uuuuuuu
WDT Reset in Sleep Mode PC + 2 u u u 10(2) 0(2) uuuuuuu
Interrupt in Idle Mode
with GIE = 0
PC + 2 u u u 0(1) 1(2) 1(2)uuuuuuu
Interrupt in Idle Mode
with GIE = 1
Vector u u u 0(1) 1(2) 1(2)uuuuuuu
Interrupt in Sleep Mode
With GIE = 0
PC + 2 u u u 0(1) 0(2) 0(2) uuuuuuu
Interrupt in Sleep Mode
with GIE = 1
Vector u u u 0(1) 0(2) 0(2) uuuuuuu
CLRWDT Instruction PC + 2 u u u 0(3)1uuuuuuu u
IDLE Instruction PC + 2 u u u 011uuuuuuu
SLEEP Instruction PC + 2 u u u 000uuuuuuu
User Instruction Writes ‘1’PC + 2u11 1 0 1 1 1 1 1 1 1 1
User Instruction Writes ‘0’PC + 2000 0 1 0 00 0 0 0 0 0
Note 1: The SLEEP instruction clears the WDTO bit.
2: The CLRWDT clears the WDTO bit only when the WDT window feature is disabled or the WDT is in the safe window.
3: This bit is also set, flagging the loss of state retention even though the true POR condition has not occurred.
4: This bit is set in hardware only; it can only be cleared in software.
5: Indicates a VDD POR. Setting the POR bit (RCON<0>) indicates a VCORE POR.
6: This bit is set when the device is originally powered up, even if power is present on VBAT.
2012 Microchip Technology Inc. DS30575A-page 97
PIC18F97J94 FAMILY
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
TOSU 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---0 uuuu(1)
TOSH 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu(1)
TOSL 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu(1)
STKPTR 64-pin 80-pin 100-pin 00-0 0000 uu-0 0000 uu-u uuuu(1)
PCLATU 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
PCLATH 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PCL 64-pin 80-pin 100-pin 0000 0000 0000 0000 PC + 2(2)
TBLPTRU 64-pin 80-pin 100-pin --00 0000 --00 0000 --uu uuuu
TBLPTRH 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TBLPTRL 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TABLAT 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PRODH 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
PRODL 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
INTCON 64-pin 80-pin 100-pin 0000 000x 0000 000x uuuu uuuu(3)
INTCON2 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu(3)
INTCON3 64-pin 80-pin 100-pin 1100 0000 1100 0000 uuuu uuuu(3)
INDF0 64-pin 80-pin 100-pin N/A N/A N/A
POSTINC0 64-pin 80-pin 100-pin N/A N/A N/A
POSTDEC0 64-pin 80-pin 100-pin N/A N/A N/A
PREINC0 64-pin 80-pin 100-pin N/A N/A N/A
PLUSW0 64-pin 80-pin 100-pin N/A N/A N/A
FSR0H 64-pin 80-pin 100-pin ---- xxxx ---- uuuu ---- uuuu
FSR0L 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
WREG 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
INDF1 64-pin 80-pin 100-pin N/A N/A N/A
POSTINC1 64-pin 80-pin 100-pin N/A N/A N/A
POSTDEC1 64-pin 80-pin 100-pin N/A N/A N/A
PREINC1 64-pin 80-pin 100-pin N/A N/A N/A
PLUSW1 64-pin 80-pin 100-pin N/A N/A N/A
FSR1H 64-pin 80-pin 100-pin ---- xxxx ---- uuuu ---- uuuu
FSR1L 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
BSR 64-pin 80-pin 100-pin ---- 0000 ---- 0000 ---- uuuu
INDF2 64-pin 80-pin 100-pin N/A N/A N/A
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
PIC18F97J94 FAMILY
DS30575A-page 98 2012 Microchip Technology Inc.
POSTINC2 64-pin 80-pin 100-pin N/A N/A N/A
POSTDEC2 64-pin 80-pin 100-pin N/A N/A N/A
PREINC2 64-pin 80-pin 100-pin N/A N/A N/A
PLUSW2 64-pin 80-pin 100-pin N/A N/A N/A
FSR2H 64-pin 80-pin 100-pin ---- xxxx ---- uuuu ---- uuuu
FSR2L 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
STATUS 64-pin 80-pin 100-pin ---x xxxx ---u uuuu ---u uuuu
TMR0H 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
TMR0L 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
T0CON 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RESERVED 64-pin 80-pin 100-pin ---- ---- ---- ---- ---- ----
OSCCON 64-pin 80-pin 100-pin 0qqq -qqq uuuu -uuu uuuu -uuu
IPR5 64-pin 80-pin 100-pin -111 -111 -uuu -uuu -uuu -uuu
IOCF 64-pin 80-pin 100-pin 0000 0000 0000 0000 qqqq qqqq
RCON(4)64-pin 80-pin 100-pin 0-11 11qq 0-qq qquu u-qq qquu
TMR1H 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
TMR1L 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
T1CON 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
TMR2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PR2 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
T2CON 64-pin 80-pin 100-pin -000 0000 -000 0000 -uuu uuuu
SSP1BUF 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
SSP1ADD 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SSP1STAT 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SSP1CON1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SSP1CON2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
CMSTAT 64-pin 80-pin 100-pin ---- -xxx ---- -uuu ---- -uuu
ADCBUF0H 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
ADCBUF0L 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
ADCON1H 64-pin 80-pin 100-pin 0--- -000 u--- -uuu u--- -uuu
ADCON1L 64-pin 80-pin 100-pin 0000 -000 uuuu -uuu uuuu -uuu
CVRCONH 64-pin 80-pin 100-pin ---0 0000 ---u uuuu ---u uuuu
CVRCONL 64-pin 80-pin 100-pin 0000 ---0 uuuu ---u uuuu ---u
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
2012 Microchip Technology Inc. DS30575A-page 99
PIC18F97J94 FAMILY
ECCP1AS 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ECCP1DEL 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
CCPR1H 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
CCPR1L 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
CCP1CON 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PIR5 64-pin 80-pin 100-pin -000 -0000 -000 -000 -uuu -uuu(3)
PIE5 64-pin 80-pin 100-pin -000 -000 -000 -000 -uuu -uuu
IPR4 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
PIR4 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu(3)
PIE4 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TMR3H 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
TMR3L 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
T3CON 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
T3GCON 64-pin 80-pin 100-pin 0000 0x00 0000 00x0 uuuu uuuu
SPBRG1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RCREG1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TXREG1 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
TXSTA1 64-pin 80-pin 100-pin 0000 0010 0000 0010 uuuu uuuu
RCSTA1 64-pin 80-pin 100-pin 0000 000x 0000 000x uuuu uuuu
T1GCON 64-pin 80-pin 100-pin 0000 0x00 0000 0x00 uuuu uuuu
IPR6 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
HLVDCON 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PSPCON 64-pin 80-pin 100-pin 0000 ---- 0000 ---- uuuu ----
PIR6 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu(3)
IPR3 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
PIR3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu(3)
PIE3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
IPR2 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
PIR2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu(3)
PIE2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
IPR1 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
PIR1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu(3)
PIE1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
PIC18F97J94 FAMILY
DS30575A-page 100 2012 Microchip Technology Inc.
PSTR1CON 64-pin 80-pin 100-pin 00-0 0001 00-0 0001 uu-u uuuu
OSCTUNE 64-pin 80-pin 100-pin --00 0000 --00 0000 --uu uuuu
TRISJ 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
TRISH 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
TRISG(5)64-pin 80-pin 100-pin 11-1 1111 11-1 1111 uu-u uuuu
TRISF 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
TRISE 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
TRISD 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
TRISC 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
TRISB 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
TRISA 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
LATJ 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
LATH 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
LATG(5)64-pin 80-pin 100-pin xx-x xxxx uu-u uuuu uu-u uuuu
LATF 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
LATE 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
LATD 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
LATC 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
LATB 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
LATA 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
PORTJ 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
PORTH 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
PORTG(5)64-pin 80-pin 100-pin xx-x x-xx xx-x x-xx uu-u u-uu
PORTF 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
PORTE 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
PORTD 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
PORTC 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
PORTB 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
PORTA 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
EECON1 64-pin 80-pin 100-pin xx-0 x000 uu-0 u000 uu-u uuuu
EECON2 64-pin 80-pin 100-pin ---- ---- ---- ---- ---- ----
RCON2 64-pin 80-pin 100-pin 0-0- 0--- q-u- 0--- 0-u- 1---
RCON3 64-pin 80-pin 100-pin ---0 q000 ---u 0000 ---u 0000
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
2012 Microchip Technology Inc. DS30575A-page 101
PIC18F97J94 FAMILY
RCON4 64-pin 80-pin 100-pin 00-0 -0-0 00-u -0-u 00-u -0-u
UFRML 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
UFRMH 64-pin 80-pin 100-pin ---- -xxx ---- -xxx ---- -uuu
UIR 64-pin 80-pin 100-pin -000 0000 -000 0000 -uuu uuuu
UEIR 64-pin 80-pin 100-pin -000 0000 -000 0000 -uuu uuuu
USTAT 64-pin 80-pin 100-pin 0--0 0000 0--0 0000 u--u uuuu
UCON 64-pin 80-pin 100-pin -0x0 000- -0x0 000- -uuu uuu-
UADDR 64-pin 80-pin 100-pin -000 0000 -000 0000 -uuu uuuu
TRISVP 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
LATVP 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
PORTVP 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
TXADDRL 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TXADDRH 64-pin 80-pin 100-pin ---- 0000 ---- 0000 ---- uuuu
RXADDRL 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RXADDRH 64-pin 80-pin 100-pin ---- 0000 ---- 0000 ---- uuuu
DMABCL 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
DMABCH 64-pin 80-pin 100-pin ---- --00 ---- --00 ---- --uu
TXBUF 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SSP1CON3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SSP1MSK 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
BAUDCON1 64-pin 80-pin 100-pin 0100 0000 0100 0000 uuuu uuuu
OSCCON2 64-pin 80-pin 100-pin 000- 000- 00q- 000- uuu- uuu-
OSCCON3 64-pin 80-pin 100-pin ---- -001 ---- -uuu ---- -uuu
OSCCON4 64-pin 80-pin 100-pin 000- ---- uuu- ---- uuu- ----
OSCCON5 64-pin 80-pin 100-pin 0-00 0000 u-uu uuuu u-uu uuuu
WPUB 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
PIE6 64-pin 80-pin 100-pin 0000 -000 0000 -000 uuuu -uuu
DMACON1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RTCCON1 64-pin 80-pin 100-pin 0-00 0000 u-uu uuuu u-uu uuuu
RTCCAL 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
RTCVALH 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
RTCVALL 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
ALRMCFG 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
PIC18F97J94 FAMILY
DS30575A-page 102 2012 Microchip Technology Inc.
ALRMRPT 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
ALRMVALH 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
ALRMVALL 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
RTCCON2 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
IOCP 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
IOCN 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PADCFG1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
CM1CON 64-pin 80-pin 100-pin 0001 1111 0001 1111 uuuu uuuu
ECCP2AS 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ECCP2DEL 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
CCPR2H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCPR2L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ECCP2CON 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ECCP3AS 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ECCP3DEL 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
CCPR3H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCPR3L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ECCP3CON 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
CCPR8H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCPR8L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCP8CON 64-pin 80-pin 100-pin --00 0000 --00 0000 --uu uuuu
CCPR9H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCPR9L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCP9CON 64-pin 80-pin 100-pin --00 0000 --00 0000 --uu uuuu
CCPR10H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCPR10L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCP10CON 64-pin 80-pin 100-pin --00 0000 --00 0000 --uu uuuu
TMR6 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PR6 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
T6CON 64-pin 80-pin 100-pin -000 0000 -000 0000 -uuu uuuu
TMR8 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PR8 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
T8CON 64-pin 80-pin 100-pin -000 0000 -000 0000 -uuu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
2012 Microchip Technology Inc. DS30575A-page 103
PIC18F97J94 FAMILY
SSP2CON3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
CM2CON 64-pin 80-pin 100-pin 0001 1111 0001 1111 uuuu uuuu
CM3CON 64-pin 80-pin 100-pin 0001 1111 0001 1111 uuuu uuuu
CCPTMRS0 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
CCPTMRS1 64-pin 80-pin 100-pin 00-0 -000 00-0 -000 uuuu uuuu
CCPTMRS2 64-pin 80-pin 100-pin ---0 -000 ---0 -000 uuuu uuuu
RCSTA2 64-pin 80-pin 100-pin 0000 000x 0000 000x uuuu uuuu
TXSTA2 64-pin 80-pin 100-pin 0000 0010 0000 0010 uuuu uuuu
BAUDCON2 64-pin 80-pin 100-pin 01x0 0000 01x0 0000 uuuu uuuu
SPBRGH1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RCSTA3 64-pin 80-pin 100-pin 0000 000x 0000 000x uuuu uuuu
TXSTA3 64-pin 80-pin 100-pin 0000 0010 0000 0010 uuuu uuuu
BAUDCON3 64-pin 80-pin 100-pin 01x0 0000 01x0 0000 uuuu uuuu
SPBRGH3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SPBRG3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RCREG3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TXREG3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
DSCONL 64-pin 80-pin 100-pin ---- -000 ---- -000 --- -uuu
DSCONH 64-pin 80-pin 100-pin 0-0- ---0 u-u- ---u u-u- ---u
DSWAKEL 64-pin 80-pin 100-pin 0000 0001 uuuu uuuu uuuu uuuu
DSWAKEH 64-pin 80-pin 100-pin ---- ---0 ---- ---u ---- ---q
DSGPR0(6)64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
DSGPR1(6)64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
DSGPR2(6)64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
DSGPR3 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
SPBRGH2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SPBRG2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RCREG2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TXREG2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PSTR2CON 64-pin 80-pin 100-pin 00-0 0001 00-0 0001 uu-u uuuu
PSTR3CON 64-pin 80-pin 100-pin 00-0 0001 00-0 0001 uu-u uuuu
SSP2STAT 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SSP2CON1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
PIC18F97J94 FAMILY
DS30575A-page 104 2012 Microchip Technology Inc.
SSP2CON2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SSP2MSK 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
TMR5H 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
TMR5L 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
T5CON 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
T5GCON 64-pin 80-pin 100-pin 0000 0x00 0000 00x0 uuuu uuuu
CCPR4H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCPR4L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCP4CON 64-pin 80-pin 100-pin --00 0000 --00 0000 --uu uuuu
CCPR5H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCPR5L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCP5CON 64-pin 80-pin 100-pin --00 0000 --00 0000 --uu uuuu
CCPR6H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCPR6L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCP6CON 64-pin 80-pin 100-pin --00 0000 --00 0000 --uu uuuu
CCPR7H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCPR7L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
CCP7CON 64-pin 80-pin 100-pin --00 0000 --00 0000 --uu uuuu
TMR4 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
PR4 64-pin 80-pin 100-pin 1111 1111 uuuu uuuu uuuu uuuu
T4CON 64-pin 80-pin 100-pin -000 0000 -000 0000 -uuu uuuu
SSP2BUF 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
SSP2ADD 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ANCFG 64-pin 80-pin 100-pin ---- -000 ---- -000 ---- -uuu
DMACON2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RCSTA4 64-pin 80-pin 100-pin 0000 000x 0000 000x uuuu uuuu
TXSTA4 64-pin 80-pin 100-pin 0000 0010 0000 0010 uuuu uuuu
BAUDCON4 64-pin 80-pin 100-pin 01x0 0000 01x0 0000 uuuu uuuu
SPBRGH4 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
SPBRG4 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RCREG4 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TXREG4 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
CTMUCON 64-pin 80-pin 100-pin 0-00 0000 0-00 0000 u-uu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
2012 Microchip Technology Inc. DS30575A-page 105
PIC18F97J94 FAMILY
CTMUCON1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
CTMUCON2 64-pin 80-pin 100-pin 0000 00-- 0000 00-- uuuu uu--
CTMUCON3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PMD0 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PMD1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PMD2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PMD3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
PMD4 64-pin 80-pin 100-pin 0000 00-- 0000 00-- uuuu uu--
MDCON 64-pin 80-pin 100-pin 0010 0--0 0010 0--0 uuuu u--u
MDSRC 64-pin 80-pin 100-pin 0--- xxxx 0--- uuuu u--- uuuu
MDCARH 64-pin 80-pin 100-pin 0xx- xxxx 0uu- uuuu uuu- uuuu
MDCARL 64-pin 80-pin 100-pin 0xx- xxxx 0uu- uuuu uuu- uuuu
ODCON1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ODCON2 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
TRISK 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
LATK 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
PORTK 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
TRISL 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
LATL 64-pin 80-pin 100-pin xxxx xxxx uuuu uuuu uuuu uuuu
PORTL 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
MEMCON 64-pin 80-pin 100-pin 0-00 --00 0-00 --00 u-uu --uu
REFO1CON 64-pin 80-pin 100-pin 0-00 0-00 u-uu u-uu u-uu u-uu
REFO1CON1 64-pin 80-pin 100-pin ---- 0000 ---- uuuu ---- uuuu
REFO1CON2 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
REFO1CON3 64-pin 80-pin 100-pin -000 0000 -uuu uuuu -uuu uuuu
REFO2CON 64-pin 80-pin 100-pin 0-00 0-00 u-uu u-uu u-uu u-uu
REFO2CON1 64-pin 80-pin 100-pin ---- 0000 ---- uuuu ---- uuuu
REFO2CON2 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
REFO2CON3 64-pin 80-pin 100-pin -000 0000 -uuu uuuu -uuu uuuu
LCDPS 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDREG 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
VLCDCON 64-pin 80-pin 100-pin 0-11 1100 u-uu uuuu u-uu uuuu
LCDREFH 64-pin 80-pin 100-pin 0-00 0000 u-uu uuuu u-uu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
PIC18F97J94 FAMILY
DS30575A-page 106 2012 Microchip Technology Inc.
LCDREFL 64-pin 80-pin 100-pin 0000 -000 uuuu -uuu uuuu -uuu
LCDSE7 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDSE6 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDSE5 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDSE4 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDSE3 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDSE2 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDSE1 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDSE0 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA63 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA62 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA61 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA60 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA59 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA58 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA57 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA56 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA55 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA54 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA53 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA52 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA51 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA50 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA49 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA48 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA47 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA46 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA45 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA44 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA43 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA42 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA41 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA40 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
2012 Microchip Technology Inc. DS30575A-page 107
PIC18F97J94 FAMILY
LCDDATA39 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA38 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA37 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA36 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA35 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA34 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA33 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA32 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA31 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA30 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA29 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA28 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA27 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA26 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA25 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA24 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA23 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA22 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA21 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA20 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA19 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA18 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA17 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA16 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA15 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA14 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA13 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA12 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA11 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA10 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA9 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA8 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA7 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
PIC18F97J94 FAMILY
DS30575A-page 108 2012 Microchip Technology Inc.
LCDDATA6 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA5 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA4 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA3 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA2 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA1 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
LCDDATA0 64-pin 80-pin 100-pin 0000 0000 uuuu uuuu uuuu uuuu
ADCON2H 64-pin 80-pin 100-pin 0000 00-- 0000 00-- uuuu uu--
ADCON2L 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCON3H 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCON3L 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCON5H 64-pin 80-pin 100-pin 000- --00 000- --00 uuu- --uu
ADCON5L 64-pin 80-pin 100-pin ---- 0000 ---- 0000 ---- uuuu
ADCHS0H 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCHS0L 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCSS1H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCSS1L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCSS0H 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCSS0L 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCHIT1H 64-pin 80-pin 100-pin ---- --00 ---- --00 ---- --uu
ADCHIT1L 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCHIT0H 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCHIT0L 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCTMUEN1H 64-pin 80-pin 100-pin -000 0000 -000 0000 uuuu uuuu
ADCTMUEN1L 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCTMUEN0H 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCTMUEN0L 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
ADCBUF25H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF25L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF24H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF24L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF23H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF23L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
2012 Microchip Technology Inc. DS30575A-page 109
PIC18F97J94 FAMILY
ADCBUF22H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF22L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF21H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF21L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF20H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF20L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF19H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF19L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF18H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF18L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF17H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF17L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF16H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF16L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF15H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF15L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF14H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF14L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF13H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF13L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF12H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF12L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF11H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF11L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF10H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF10L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF9H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF9L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF8H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF8L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF7H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF7L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF6H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
PIC18F97J94 FAMILY
DS30575A-page 110 2012 Microchip Technology Inc.
ADCBUF6L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF5H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF5L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF4H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF4L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF3H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF3L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF2H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF2L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF1H 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ADCBUF1L 64-pin 80-pin 100-pin xxxx xxxx xxxx xxxx uuuu uuuu
ANCON1 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
ANCON2 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
ANCON3 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR52_53 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR50_51 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR48_49 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR46_47 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR44_45 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR42_43 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR40_41 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR38_39 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR36_37 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR34_35 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR32_33 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR30_31 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR28_29 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR26_27 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR24_25 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR22_23 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR20_21 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR18_19 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR16_17 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
2012 Microchip Technology Inc. DS30575A-page 111
PIC18F97J94 FAMILY
RPINR14_15 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR12_13 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR10_11 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR8_9 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR6_7 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR4_5 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR2_3 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPINR0_1 64-pin 80-pin 100-pin 1111 1111 1111 1111 uuuu uuuu
RPOR46 64-pin 80-pin 100-pin ---- 0000 ---- 0000 ---- uuuu
RPOR44_45 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR42_43 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR40_41 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR38_39 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR36_37 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR34_35 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR32_33 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR30_31 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR28_29 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR26_27 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR24_25 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR22_23 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR20_21 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR18_19 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR16_17 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR14_15 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR12_13 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR10_11 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR8_9 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR6_7 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR4_5 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR2_3 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
RPOR0_1 64-pin 80-pin 100-pin 0000 0000 0000 0000 uuuu uuuu
UCFG 64-pin 80-pin 100-pin 00-0 -000 00-0 -000 uu-u -uuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
PIC18F97J94 FAMILY
DS30575A-page 112 2012 Microchip Technology Inc.
UIE 64-pin 80-pin 100-pin -000 0000 -000 0000 -uuu uuuu
UEIE 64-pin 80-pin 100-pin 0--0 0000 0--0 0000 u--u uuuu
UEP0 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP1 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP2 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP3 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP4 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP5 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP6 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP7 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP8 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP9 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP10 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP11 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP12 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP13 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP14 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
UEP15 64-pin 80-pin 100-pin ---0 0000 ---0 0000 ---u uuuu
TABLE 5-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Register Applicable Devices
Power-on Reset,
Brown-out
Reset
MCLR Resets,
WDT Reset,
RESET Instruction,
Stack Resets
Wake-up via
WDT or Interrupt
Legend: u = unchanged; x = unknown; - = unimplemented bit, read as ‘0’; q = value depends on condition.
Shaded cells indicate that conditions do not apply for the designated device.
Note 1: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
4: See Table 5-2 for Reset value for specific condition.
5: Bits 7,6 are unimplemented on 64 and 80-pin devices.
6: If the VBAT is always powered, the DSGPx register values will remain unchanged after the first POR.
2012 Microchip Technology Inc. DS30575A-page 113
PIC18F97J94 FAMILY
6.0 MEMORY ORGANIZATION
PIC18F97J94 family devices have these types of
memory:
• Program Memory
• Data RAM
As Harvard architecture devices, the data and program
memories use separate busses. This enables
concurrent access of the two memory spaces.
Additional detailed information on the operation of the
Flash program memory is provided in Section 7.0
“Flash Program Memory”.
FIGURE 6-1: MEMORY MAPS FOR PIC18F97J94 FAMILY DEVICES
Note: Sizes of memory areas are not to scale. Sizes of program memory areas are enhanced to show detail.
Unimplemented
Read as ‘0’
Unimplemented
Read as ‘0’
000000h
1FFFFFh
01FFFFh
00FFFFh
PC<20:0>
Stack Level 1
Stack Level 31
CALL, CALLW, RCALL,
RETURN, RETFIE, RETLW,
21
User Memory Space
On-Chip
Memory
ADDULNK, SUBULNK
Unimplemented
Read as ‘0’
On-Chip
Memory
007FFFh
Unimplemented
Read as ‘0’
On-Chip
Memory
017FFFh
Config Words
Config Words
Config Words
Config Words
PIC18FX5J94 PIC18FX6J94 PIC18FX6J99 PIC18FX7J94
On-Chip
Memory
PIC18F97J94 FAMILY
DS30575A-page 114 2012 Microchip Technology Inc.
6.1 Program Memory Organization
PIC18 microcontrollers implement a 21-bit Program
Counter that is capable of addressing a 2-Mbyte
program memory space. Accessing a location between
the upper boundary of the physically implemented
memory and the 2-Mbyte address will return all ‘0’s (a
NOP instruction).
The entire PIC18F97J94 family offers a range of
on-chip Flash program memory sizes, from 32 Kbytes
(up to 16,384 single-word instructions) to 128 Kbytes
(65,536 single-word instructions).
• PIC18F65J94, PIC18F85J94 and PIC18F95J94 –
32 Kbytes of Flash memory, storing up to
16,384 single-word instructions
• PIC18F66J94, PIC18F86J94 and PIC18F96J94 –
64 Kbytes of Flash memory, storing up to
32,768 single-word instructions
• PIC18F66J99, PIC18F86J99 and PIC18F96J99 –
96 Kbytes of Flash Memory, storing up to
49,152 single-word instructions
• PIC18F67J94, PIC18F87J94 and PIC18F97J94 –
128 Kbytes of Flash memory, storing up to
65,536 single-word instructions
The program memory maps for individual family
members are shown in Figure 6-1.
6.1.1 HARD MEMORY VECTORS
All PIC18 devices have a total of three hard-coded
return vectors in their program memory space. The
Reset vector address is the default value to which the
Program Counter returns on all device Resets; it is
located at 0000h.
PIC18 devices also have two interrupt vector
addresses for handling high-priority and low-priority
interrupts. The high-priority interrupt vector is located at
0008h and the low-priority interrupt vector is at 0018h.
The locations of these vectors are shown, in relation to
the program memory map, in Figure 6-2.
6.1.2 FLASH CONFIGURATION WORDS
Because PIC18F97J94 family devices do not have per-
sistent configuration memory, the top eight words of
on-chip program memory are reserved for configuration
information. On Reset, the configuration information is
copied into the Configuration registers.
The Configuration Words are stored in their program
memory location in numerical order, starting with the
lower byte of CONFIG1 at the lowest address and end-
ing with the upper byte of CONFIG8. The actual
addresses of the Flash Configuration Word for devices
in the PIC18F97J94 family are shown in Tab l e 6-1 .
Their location in the memory map is shown with the
other memory vectors in Figure 6-2. Additional details
on the device Configuration Words are provided in
Section 28.1 “Configuration Bits”.
FIGURE 6-2: HARD VECTOR FOR
PIC18F97J94 FAMILY
DEVICES
TABLE 6-1: FLASH CONFIGURATION
WORD FOR PIC18F97J94
FAMILY DEVICES
Device
Program
Memory
(Kbytes)
Configuration
Word Addresses
PIC18F65J94
PIC18F85J94
PIC18F95J94
32 7FF0h to 7FFFh
PIC18F66J94
PIC18F86J94
PIC18F96J94
64 FFF0h to FFFFh
PIC18F66J99
PIC18F86J99
PIC18F96J99
96 17FF0h to 17FFFh
PIC18F67J94
PIC18F87J94
PIC18F97J94
128 1FFF0h to 1FFFFh
Reset Vector
Low-Priority Interrupt Vector
0000h
0018h
On-Chip
Program Memory
High-Priority Interrupt Vector 0008h
1FFFFFh
Read ‘0’
Legend: (Top of Memory) represents upper boundary
of on-chip program memory space (see
Figure 6-1 for device-specific values).
Shaded area represents unimplemented
memory. Areas are not shown to scale.
Flash Configuration Words
(Top of Memory-17)
(Top of Memory)
2012 Microchip Technology Inc. DS30575A-page 115
PIC18F97J94 FAMILY
6.1.3 PROGRAM COUNTER
The Program Counter (PC) specifies the address of the
instruction to fetch for execution. The PC is 21 bits wide
and contained in three separate 8-bit registers.
The low byte, known as the PCL register, is both
readable and writable. The high byte, or PCH register,
contains the PC<15:8> bits and is not directly readable
or writable. Updates to the PCH register are performed
through the PCLATH register. The upper byte is called
PCU. This register contains the PC<20:16> bits; it is
also not directly readable or writable. Updates to the
PCU register are performed through the PCLATU
register.
The contents of PCLATH and PCLATU are transferred
to the Program Counter by any operation that writes
PCL. Similarly, the upper two bytes of the Program
Counter are transferred to PCLATH and PCLATU by an
operation that reads PCL. This is useful for computed
offsets to the PC (see Section 6.1.6.1 “Computed
GOTO”).
The PC addresses bytes in the program memory. To
prevent the PC from becoming misaligned with word
instructions, the Least Significant bit of PCL is fixed to
a value of ‘0’. The PC increments by two to address
sequential instructions in the program memory.
The CALL, RCALL, GOTO and program branch
instructions write to the Program Counter directly. For
these instructions, the contents of PCLATH and
PCLATU are not transferred to the Program Counter.
6.1.4 RETURN ADDRESS STACK
The return address stack enables execution of any
combination of up to 31 program calls and interrupts.
The PC is pushed onto the stack when a CALL or
RCALL instruction is executed or an interrupt is
Acknowledged. The PC value is pulled off the stack on
a RETURN, RETLW or a RETFIE instruction. The value
also is pulled off the stack on ADDULNK and SUBULNK
instructions, if the extended instruction set is enabled.
PCLATU and PCLATH are not affected by any of the
RETURN or CALL instructions.
The stack operates as a 31-word by 21-bit RAM and a
5-bit Stack Pointer, STKPTR. The stack space is not
part of either program or data space. The Stack Pointer
is readable and writable and the address on the top of
the stack is readable and writable through the
Top-of-Stack Special Function Registers. Data can also
be pushed to, or popped from, the stack using these
registers.
A CALL type instruction causes a push onto the stack.
The Stack Pointer is first incremented and the location
pointed to by the Stack Pointer is written with the
contents of the PC (already pointing to the instruction
following the CALL). A RETURN type instruction causes
a pop from the stack. The contents of the location
pointed to by the STKPTR are transferred to the PC
and then the Stack Pointer is decremented.
The Stack Pointer is initialized to ‘00000’ after all
Resets. There is no RAM associated with the location
corresponding to a Stack Pointer value of ‘00000’; this
is only a Reset value. Status bits indicate if the stack is
full, has overflowed or has underflowed.
6.1.4.1 Top-of-Stack Access
Only the top of the return address stack (TOS) is
readable and writable. A set of three registers,
TOSU:TOSH:TOSL, holds the contents of the stack
location pointed to by the STKPTR register
(Figure 6-3). This allows users to implement a software
stack, if necessary. After a CALL, RCALL or interrupt (or
ADDULNK and SUBULNK instructions, if the extended
instruction set is enabled), the software can read the
pushed value by reading the TOSU:TOSH:TOSL regis-
ters. These values can be placed on a user-defined
software stack. At return time, the software can return
these values to TOSU:TOSH:TOSL and do a return.
While accessing the stack, users must disable the
Global Interrupt Enable bits to prevent inadvertent
stack corruption.
FIGURE 6-3: RETURN ADDRESS STACK AND ASSOCIATED REGISTERS
00011
001A34h
11111
11110
11101
00010
00001
00000
00010
Return Address Stack <20:0>
To p - o f - St a c k
000D58h
TOSLTOSHTOSU
34h1Ah00h
STKPTR<4:0>
Top-of-Stack Registers Stack Pointer
PIC18F97J94 FAMILY
DS30575A-page 116 2012 Microchip Technology Inc.
6.1.4.2 Return Stack Pointer (STKPTR)
The STKPTR register (Register 6-1) contains the Stack
Pointer value, the STKFUL (Stack Full) status bit and
the STKUNF (Stack Underflow) status bits. The value
of the Stack Pointer can be 0 through 31. The Stack
Pointer increments before values are pushed onto the
stack and decrements after values are popped off the
stack. On Reset, the Stack Pointer value will be zero.
The user may read and write the Stack Pointer value.
This feature can be used by a Real-Time Operating
System (RTOS) for return-stack maintenance.
After the PC is pushed onto the stack, 31 times (without
popping any values off the stack), the STKFUL bit is
set. The STKFUL bit is cleared by software or by a
POR.
What happens when the stack becomes full depends
on the state of the STVREN (Stack Overflow Reset
Enable) Configuration bit. (For a description of the
device Configuration bits, see Section 28.1 “Configu-
ration Bits”.) If STVREN is set (default), the 31st push
will push the (PC + 2) value onto the stack, set the
STKFUL bit and reset the device. The STKFUL bit will
remain set and the Stack Pointer will be set to zero.
If STVREN is cleared, the STKFUL bit will be set on the
31st push and the Stack Pointer will increment to 31.
Any additional pushes will not overwrite the 31st push
and the STKPTR will remain at 31.
When the stack has been popped enough times to
unload the stack, the next pop will return a value of zero
to the PC and set the STKUNF bit, while the Stack
Pointer remains at zero. The STKUNF bit will remain
set until cleared by software or until a POR occurs.
6.1.4.3 PUSH and POP Instructions
Since the Top-of-Stack is readable and writable, the
ability to push values onto the stack and pull values off
the stack, without disturbing normal program execu-
tion, is a desirable feature. The PIC18 instruction set
includes two instructions, PUSH and POP, that permit
the TOS to be manipulated under software control.
TOSU, TOSH and TOSL can be modified to place data
or a return address on the stack.
The PUSH instruction places the current PC value onto
the stack. This increments the Stack Pointer and loads
the current PC value onto the stack.
The POP instruction discards the current TOS by
decrementing the Stack Pointer. The previous value
pushed onto the stack then becomes the TOS value.
Note: Returning a value of zero to the PC on an
underflow has the effect of vectoring the
program to the Reset vector, where the
stack conditions can be verified and
appropriate actions can be taken. This is
not the same as a Reset, as the contents
of the SFRs are not affected.
REGISTER 6-1: STKPTR: STACK POINTER REGISTER
R/C-0 R/C-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
STKFUL(1)STKUNF(1)— SP4 SP3 SP2 SP1 SP0
bit 7 bit 0
Legend: C = Clearable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 STKFUL: Stack Full Flag bit(1)
1 = Stack has become full or overflowed
0 = Stack has not become full or overflowed
bit 6 STKUNF: Stack Underflow Flag bit(1)
1 = Stack underflow has occurred
0 = Stack underflow did not occur
bit 5 Unimplemented: Read as ‘0’
bit 4-0 SP<4:0>: Stack Pointer Location bits
Note 1: Bit 7 and bit 6 are cleared by user software or by a POR.
2012 Microchip Technology Inc. DS30575A-page 117
PIC18F97J94 FAMILY
6.1.4.4 Stack Full and Underflow Resets
Device Resets on stack overflow and stack underflow
conditions are enabled by setting the STVREN bit
(CONFIG1L<5>). When STVREN is set, a full or under-
flow condition will set the appropriate STKFUL or
STKUNF bit and then cause a device Reset. When
STVREN is cleared, a full or underflow condition will set
the appropriate STKFUL or STKUNF bit, but not cause
a device Reset. The STKFUL or STKUNF bits are
cleared by user software or a Power-on Reset.
6.1.5 FAST REGISTER STACK
A Fast Register Stack is provided for the STATUS,
WREG and BSR registers to provide a “fast return”
option for interrupts. This stack is only one level deep
and is neither readable nor writable. It is loaded with the
current value of the corresponding register when the
processor vectors for an interrupt. All interrupt sources
will push values into the Stack registers. The values in
the registers are then loaded back into the working
registers if the RETFIE,FAST instruction is used to
return from the interrupt.
If both low and high-priority interrupts are enabled, the
Stack registers cannot be used reliably to return from
low-priority interrupts. If a high-priority interrupt occurs
while servicing a low-priority interrupt, the Stack
register values stored by the low-priority interrupt will
be overwritten. In these cases, users must save the key
registers in software during a low-priority interrupt.
If interrupt priority is not used, all interrupts may use the
Fast Register Stack for returns from interrupt. If no
interrupts are used, the Fast Register Stack can be
used to restore the STATUS, WREG and BSR registers
at the end of a subroutine call. To use the Fast Register
Stack for a subroutine call, a CALL label,FAST
instruction must be executed to save the STATUS,
WREG and BSR registers to the Fast Register Stack. A
RETURN,FAST instruction is then executed to restore
these registers from the Fast Register Stack.
Example 6-1 shows a source code example that uses
the Fast Register Stack during a subroutine call and
return.
EXAMPLE 6-1: FAST REGISTER STACK
CODE EXAMPLE
6.1.6 LOOK-UP TABLES IN PROGRAM
MEMORY
There may be programming situations that require the
creation of data structures, or look-up tables, in
program memory. For PIC18 devices, look-up tables
can be implemented in two ways:
• Computed GOTO
• Table Reads
6.1.6.1 Computed GOTO
A computed GOTO is accomplished by adding an offset
to the Program Counter. An example is shown in
Example 6-2.
A look-up table can be formed with an ADDWF PCL
instruction and a group of RETLW nn instructions. The
W register is loaded with an offset into the table before
executing a call to that table. The first instruction of the
called routine is the ADDWF PCL instruction. The next
instruction executed will be one of the RETLW nn
instructions that returns the value, ‘nn’, to the calling
function.
The offset value (in WREG) specifies the number of
bytes that the Program Counter should advance and
should be multiples of two (LSb = 0).
In this method, only one data byte may be stored in
each instruction location and room on the return
address stack is required.
EXAMPLE 6-2: COMPUTED GOTO USING
AN OFFSET VALUE
6.1.6.2 Table Reads
A better method of storing data in program memory
allows two bytes of data to be stored in each instruction
location.
Look-up table data may be stored, two bytes per
program word, while programming. The Table Pointer
(TBLPTR) specifies the byte address and the Table
Latch (TABLAT) contains the data that is read from the
program memory. Data is transferred from program
memory one byte at a time.
The table read operation is discussed further in
Section 7.1 “Table Reads and Table Writes”.
CALL SUB1, FAST ;STATUS, WREG, BSR
;SAVED IN FAST REGISTER
;STACK
SUB1
RETURN FAST ;RESTORE VALUES SAVED
;IN FAST REGISTER STACK
MOVF OFFSET, W
CALL TABLE
ORG nn00h
TABLE ADDWF PCL
RETLW nnh
RETLW nnh
RETLW nnh
.
.
.
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6.2 PIC18 Instruction Cycle
6.2.1 CLOCKING SCHEME
The microcontroller clock input, whether from an
internal or external source, is internally divided by four
to generate four non-overlapping quadrature clocks
(Q1, Q2, Q3 and Q4). Internally, the Program Counter
is incremented on every Q1, with the instruction
fetched from the program memory and latched into the
Instruction Register (IR) during Q4.
The instruction is decoded and executed during the
following Q1 through Q4. The clocks and instruction
execution flow are shown in Figure 6-4.
6.2.2 INSTRUCTION FLOW/PIPELINING
An “Instruction Cycle” consists of four Q cycles, Q1
through Q4. The instruction fetch and execute are pipe-
lined in such a manner that a fetch takes one instruction
cycle, while the decode and execute take another
instruction cycle. However, due to the pipelining, each
instruction effectively executes in one cycle. If an
instruction (such as GOTO) causes the Program Coun-
ter to change, two cycles are required to complete the
instruction. (See Example 6-3.)
A fetch cycle begins with the Program Counter (PC)
incrementing in Q1.
In the execution cycle, the fetched instruction is latched
into the Instruction Register (IR) in cycle Q1. This
instruction is then decoded and executed during the
Q2, Q3 and Q4 cycles. Data memory is read during Q2
(operand read) and written during Q4 (destination
write).
FIGURE 6-4: CLOCK/INSTRUCTION CYCLE
EXAMPLE 6-3: INSTRUCTION PIPELINE FLOW
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
Q1
Q2
Q3
Q4
PC
OSC2/CLKO
(RC mode)
PC PC + 2 PC + 4
Fetch INST (PC)
Execute INST (PC – 2)
Fetch INST (PC + 2)
Execute INST (PC)
Fetch INST (PC + 4)
Execute INST (PC + 2)
Internal
Phase
Clock
All instructions are single cycle, except for any program branches. These take two cycles since the fetch instruction
is “flushed” from the pipeline while the new instruction is being fetched and then executed.
TCY0TCY1TCY2TCY3TCY4TCY5
1. MOVLW 55h Fetch 1 Execute 1
2. MOVWF PORTB Fetch 2 Execute 2
3. BRA SUB_1 Fetch 3 Execute 3
4. BSF PORTA, BIT3 (Forced NOP) Fetch 4 Flush (NOP)
5. Instruction @ address SUB_1 Fetch SUB_1 Execute SUB_1
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6.2.3 INSTRUCTIONS IN PROGRAM
MEMORY
The program memory is addressed in bytes. Instruc-
tions are stored as two or four bytes in program
memory. The Least Significant Byte of an instruction
word is always stored in a program memory location
with an even address (LSB = 0). To maintain alignment
with instruction boundaries, the PC increments in steps
of two and the LSB will always read ‘0’ (see
Section 6.1.3 “Program Counter”).
Figure 6-5 shows an example of how instruction words
are stored in the program memory.
The CALL and GOTO instructions have the absolute
program memory address embedded into the instruc-
tion. Since instructions are always stored on word
boundaries, the data contained in the instruction is a
word address. The word address is written to PC<20:1>
which accesses the desired byte address in program
memory. Instruction #2 in Figure 6-5 shows how the
instruction, GOTO 0006h, is encoded in the program
memory. Program branch instructions, which encode a
relative address offset, operate in the same manner. The
offset value stored in a branch instruction represents the
number of single-word instructions that the PC will be
offset by. For more details on the instruction set, see
Section 29.0 “Instruction Set Summary”.
FIGURE 6-5: INSTRUCTIONS IN PROGRAM MEMORY
6.2.4 TWO-WORD INSTRUCTIONS
The standard PIC18 instruction set has four, two-word
instructions: CALL, MOVFF, GOTO and LSFR. In all
cases, the second word of the instructions always has
‘1111’ as its four Most Significant bits. The other 12 bits
are literal data, usually a data memory address.
The use of ‘1111’ in the 4 MSbs of an instruction
specifies a special form of NOP. If the instruction is
executed in proper sequence, immediately after the
first word, the data in the second word is accessed and
used by the instruction sequence. If the first word is
skipped, for some reason, and the second word is
executed by itself, a NOP is executed instead. This is
necessary for cases when the two-word instruction is
preceded by a conditional instruction that changes the
PC. Example 6-4 shows how this works.
EXAMPLE 6-4: TWO-WORD INSTRUCTIONS
Word Address
LSB = 1LSB = 0
Program Memory
Byte Locations
000000h
000002h
000004h
000006h
Instruction 1: MOVLW 055h 0Fh 55h 000008h
Instruction 2: GOTO 0006h EFh 06h 00000Ah
F0h 00h 00000Ch
Instruction 3: MOVFF 123h, 456h C1h 23h 00000Eh
F4h 56h 000010h
000012h
000014h
Note: For information on two-word instructions
in the extended instruction set, see
Section 6.5 “Program Memory and the
Extended Instruction Set”.
CASE 1:
Object Code Source Code
0110 0110 0000 0000 TSTFSZ REG1 ; is RAM location 0?
1100 0001 0010 0011 MOVFF REG1, REG2 ; No, skip this word
1111 0100 0101 0110 ; Execute this word as a NOP
0010 0100 0000 0000 ADDWF REG3 ; continue code
CASE 2:
Object Code Source Code
0110 0110 0000 0000 TSTFSZ REG1 ; is RAM location 0?
1100 0001 0010 0011 MOVFF REG1, REG2 ; Yes, execute this word
1111 0100 0101 0110 ; 2nd word of instruction
0010 0100 0000 0000 ADDWF REG3 ; continue code
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6.3 Data Memory Organization
The data memory in PIC18 devices is implemented as
static RAM. Each register in the data memory has a
12-bit address, allowing up to 4,096 bytes of data
memory. The memory space is divided into as many as
16 banks that contain 256 bytes each. PIC18F97J94
family devices implement all 16 banks, for a total of
4Kbytes.
Figure 6-6 and Figure 6-7 show the data memory
organization for the devices.
The data memory contains Special Function Registers
(SFRs) and General Purpose Registers (GPRs). The
SFRs are used for control and status of the controller
and peripheral functions, while GPRs are used for data
storage and scratchpad operations in the user’s
application. Any read of an unimplemented location will
read as ‘0’s.
The instruction set and architecture allow operations
across all banks. The entire data memory may be
accessed by Direct, Indirect or Indexed Addressing
modes. Addressing modes are discussed later in this
section.
To ensure that commonly used registers (select SFRs
and select GPRs) can be accessed in a single cycle,
PIC18 devices implement an Access Bank. This is a
256-byte memory space that provides fast access to
select SFRs and the lower portion of GPR Bank 0 with-
out using the Bank Select Register. For details on the
Access RAM, see Section 6.3.2 “Access Bank”.
6.3.1 BANK SELECT REGISTER
Large areas of data memory require an efficient
addressing scheme to make it possible for rapid access
to any address. Ideally, this means that an entire
address does not need to be provided for each read or
write operation. For PIC18 devices, this is accom-
plished with a RAM banking scheme. This divides the
memory space into 16 contiguous banks of 256 bytes.
Depending on the instruction, each location can be
addressed directly by its full 12-bit address, or an
eight-bit, low-order address and a four-bit Bank Pointer.
Most instructions in the PIC18 instruction set make use
of the Bank Pointer, known as the Bank Select Register
(BSR). This SFR holds the four Most Significant bits of
a location’s address. The instruction itself includes the
eight Least Significant bits. Only the four lower bits of
the BSR are implemented (BSR<3:0>). The upper four
bits are unused, always read as ‘0’ and cannot be
written to. The BSR can be loaded directly by using the
MOVLB instruction.
The value of the BSR indicates the bank in data
memory. The eight bits in the instruction show the loca-
tion in the bank and can be thought of as an offset from
the bank’s lower boundary. The relationship between
the BSR’s value and the bank division in data memory
is shown in Figure 6-7.
Since up to 16 registers may share the same low-order
address, the user must always be careful to ensure that
the proper bank is selected before performing a data
read or write. For example, writing what should be
program data to an eight-bit address of F9h, while the
BSR is 0Fh, will end up resetting the Program Counter.
While any bank can be selected, only those banks that
are actually implemented can be read or written to.
Writes to unimplemented banks are ignored, while
reads from unimplemented banks will return ‘0’s. Even
so, the STATUS register will still be affected as if the
operation was successful. The data memory map in
Figure 6-6 indicates which banks are implemented.
In the core PIC18 instruction set, only the MOVFF
instruction fully specifies the 12-bit address of the
source and target registers. When this instruction
executes, it ignores the BSR completely. All other
instructions include only the low-order address as an
operand and must use either the BSR or the Access
Bank to locate their target registers.
Note: The operation of some aspects of data
memory are changed when the PIC18
extended instruction set is enabled. See
Section 6.6 “Data Memory and the
Extended Instruction Set” for more
information.
2012 Microchip Technology Inc. DS30575A-page 121
PIC18F97J94 FAMILY
FIGURE 6-6: DATA MEMORY MAP FOR PIC18F97J94 FAMILY DEVICES
00h
5Fh
60h
FFh
Access Bank
When a = 0:
The BSR is ignored and the
Access Bank is used.
The first 96 bytes are general
purpose RAM (from Bank 0).
The second 160 bytes are
Special Function Registers
(from Bank 15).
When a = 1:
The BSR specifies the bank
used by the instruction.
Access RAM High
Access RAM Low
(SFRs)
Bank 0
Bank 1
Bank 14
Bank 15
Data Memory Map
BSR<3:0>
= 0000
= 0001
= 1111
060h
05Fh
F60h
FFFh
F5Fh
F00h
EFFh
1FFh
100h
0FFh
000h
Access RAM
FFh
00h
FFh
00h
FFh
00h
GPR
GPR
SFR
Bank 2
= 0010
2FFh
200h
Bank 3
FFh
00h
GPR
FFh
= 0011
GPR
GPR
GPR
GPR
GPR
4FFh
400h
5FFh
500h
3FFh
300h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
00h
= 0110
= 0111
= 0101
= 0100 Bank 4
Bank 5
Bank 6
Bank 7
Bank 8
= 1110
6FFh
600h
7FFh
700h
800h
Bank 9
Bank 10
Bank 11
Bank 12
Bank 13
8FFh
900h
9FFh
A00h
AFFh
B00h
BFFh
C00h
CFFh
D00h
DFFh
E00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
SFR
GPR
GPR
GPR
GPR
GPR
GPR
Note 1: Addresses, DFAh through F5Fh, are also SFRs, but are not part of the Access RAM. Users must always use
the complete address, or load the proper BSR value, to access these registers.
= 1000
= 1001
= 1010
= 1011
= 1100
= 1101 FAh SFR DFAh
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DS30575A-page 122 2012 Microchip Technology Inc.
FIGURE 6-7: USE OF THE BANK SELECT REGISTER (DIRECT ADDRESSING)
6.3.2 ACCESS BANK
While the use of the BSR, with an embedded 8-bit
address, allows users to address the entire range of data
memory, it also means that the user must ensure that the
correct bank is selected. If not, data may be read from,
or written to, the wrong location. This can be disastrous
if a GPR is the intended target of an operation, but an
SFR is written to instead. Verifying and/or changing the
BSR for each read or write to data memory can become
very inefficient.
To streamline access for the most commonly used data
memory locations, the data memory is configured with
an Access Bank, which allows users to access a
mapped block of memory without specifying a BSR.
The Access Bank consists of the first 96 bytes of
memory (00h-5Fh) in Bank 0 and the last 160 bytes of
memory (60h-FFh) in Bank 15. The lower half is known
as the “Access RAM” and is composed of GPRs. The
upper half is where the device’s SFRs are mapped.
These two areas are mapped contiguously in the
Access Bank and can be addressed in a linear fashion
by an eight-bit address (Figure 6-6).
The Access Bank is used by core PIC18 instructions
that include the Access RAM bit (the ‘a’ parameter in
the instruction). When ‘a’ is equal to ‘1’, the instruction
uses the BSR and the 8-bit address included in the
opcode for the data memory address. When ‘a’ is ‘0’,
however, the instruction is forced to use the Access
Bank address map. In that case, the current value of
the BSR is ignored entirely.
Using this “forced” addressing allows the instruction to
operate on a data address in a single cycle without
updating the BSR first. For 8-bit addresses of 60h and
above, this means that users can evaluate and operate
on SFRs more efficiently. The Access RAM below 60h
is a good place for data values that the user might need
to access rapidly, such as immediate computational
results or common program variables.
Access RAM also allows for faster and more code
efficient context saving and switching of variables.
The mapping of the Access Bank is slightly different
when the extended instruction set is enabled (XINST
Configuration bit = 1). This is discussed in more detail
in Section 6.6.3 “Mapping the Access Bank in
Indexed Literal Offset Mode”.
6.3.3 GENERAL PURPOSE
REGISTER FILE
PIC18 devices may have banked memory in the GPR
area. This is data RAM which is available for use by all
instructions. GPRs start at the bottom of Bank 0
(address 000h) and grow upwards towards the bottom of
the SFR area. GPRs are not initialized by a Power-on
Reset and are unchanged on all other Resets.
Note 1: The Access RAM bit of the instruction can be used to force an override of the selected bank (BSR<3:0>)
to the registers of the Access Bank.
2: The MOVFF instruction embeds the entire 12-bit address in the instruction.
Data Memory
Bank Select(2)
70
From Opcode(2)
0000
000h
100h
200h
300h
F00h
E00h
FFFh
Bank 0
Bank 1
Bank 2
Bank 14
Bank 15
00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
FFh
Bank 3
through
Bank 13
0010 1
70
BSR(1)
1111111
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6.3.4 SPECIAL FUNCTION REGISTERS
The Special Function Registers (SFRs) are registers
used by the CPU and peripheral modules for controlling
the desired operation of the device. These registers are
implemented as static RAM. SFRs start at the top of
data memory (FFFh) and extend downward to occupy
all of Bank 15 (F00h to FFFh), Bank 14 (E00h to EFFh)
and part of Bank 13 (DFAh to DFFh).
A list of these registers is given in Table 6-2.
The SFRs can be classified into two sets: those
associated with the “core” device functionality (ALU,
Resets and interrupts) and those related to the
peripheral functions. The Reset and Interrupt registers
are described in their respective chapters, while the
ALU’s STATUS register is described later in this section.
Registers related to the operation of the peripheral
features are described in the chapter for that peripheral.
The SFRs are typically distributed among the
peripherals whose functions they control. Unused SFR
locations are unimplemented and read as ‘0’s.
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DS30575A-page 124 2012 Microchip Technology Inc.
TABLE 6-2: REGISTER FILE SUMMARY
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
FFFh TOSU — — — Top-of-Stack Upper Byte (TOS<20:16>)
FFEh TOSH Top-of-Stack High Byte (TOS<15:8>)
FFDh TOSL Top-of-Stack Low Byte (TOS<7:0>)
FFCh STKPTR STKFUL STKUNF —STKPTR
FFBh PCLATU — — — Holding Register for PC<20:16>
FFAh PCLATH Holding Register for PC<15:8>
FF9h PCL PC Low Byte (PC<7:0>)
FF8h TBLPTRU —— ACSS Program Memory Table Pointer Upper Byte (TBLPTR<20:16>)
FF7h TBLPTRH Program Memory Table Pointer High Byte (TBLPTR<15:8>)
FF6h TBLPTRL Program Memory Table Pointer Low Byte (TBLPTR<7:0>)
FF5h TABLAT Program Memory Table Latch
FF4h PRODH Product Register High Byte
FF3h PRODL Product Register Low Byte
FF2h INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE IOCIE TMR0IF INT0IF IOCIF
FF1h INTCON2 RBPU INTEDG0 INTEDG1 INTEDG2 INTEDG3 TMR0IP INT3IP IOCIP
FF0h INTCON3 INT2IP INT1IP INT3IE INT2IE INT1IE INT3IF INT2IF INT1IF
FEFh INDF0 Uses contents of FSR0 to address data memory – value of FSR0 not changed (not a physical register)
FEEh POSTINC0 Uses contents of FSR0 to address data memory – value of FSR0 post-incremented (not a physical register)
FEDh POSTDEC0 Uses contents of FSR0 to address data memory – value of FSR0 post-decremented (not a physical register)
FECh PREINC0 Uses contents of FSR0 to address data memory – value of FSR0 pre-incremented (not a physical register)
FEBh PLUSW0 Uses contents of FSR0 to address data memory – value of FSR0 pre-incremented (not a physical register) – value of
FSR0 offset by W
FEAh FSR0H — — — — Indirect Data Memory Address Pointer 0 High
FE9h FSR0L Indirect Data Memory Address Pointer 0 Low Byte
FE8h WREG Working Register
FE7h INDF1 Uses contents of FSR1 to address data memory – value of FSR1 not changed (not a physical register)
FE6h POSTINC1 Uses contents of FSR1 to address data memory – value of FSR1 post-incremented (not a physical register)
FE5h POSTDEC1 Uses contents of FSR1 to address data memory – value of FSR1 post-decremented (not a physical register)
FE4h PREINC1 Uses contents of FSR1 to address data memory – value of FSR1 pre-incremented (not a physical register)
FE3h PLUSW1 Uses contents of FSR1 to address data memory – value of FSR1 pre-incremented (not a physical register) – value of
FSR1 offset by W
FE2h FSR1H — — — — Indirect Data Memory Address Pointer 1 High
FE1h FSR1L Indirect Data Memory Address Pointer 1 Low Byte
FE0h BSR — — — — Bank Select Register
FDFh INDF2 Uses contents of FSR2 to address data memory – value of FSR2 not changed (not a physical register)
FDEh POSTINC2 Uses contents of FSR2 to address data memory – value of FSR2 post-incremented (not a physical register)
FDDh POSTDEC2 Uses contents of FSR2 to address data memory – value of FSR2 post-decremented (not a physical register)
FDCh PREINC2 Uses contents of FSR2 to address data memory – value of FSR2 pre-incremented (not a physical register)
FDBh PLUSW2 Uses contents of FSR2 to address data memory – value of FSR2 pre-incremented (not a physical register) – value of
FSR2 offset by W
FDAh FSR2H — — — — Indirect Data Memory Address Pointer 2 High
FD9h FSR2L Indirect Data Memory Address Pointer 2 Low Byte
FD8h STATUS — — —N OV ZDCC
FD7h TMR0H Timer0 Register High Byte
FD6h TMR0L Timer0 Register Low Byte
FD5h T0CON TMR0ON T08BIT T0CS1 T0CS0 PSA T0PS2 T0PS1 T0PS0
FD4h Unimplemented — — — — — — — —
FD3h OSCCON IDLEN COSC2 COSC1 COSC0 — NOSC2 NOSC1 NOSC0
FD2h IPR5 —ACTORSIP ACTLOCKIP TMR8IP — TMR6IP TMR5IP TMR4IP
FD1h IOCF IOCF7 IOCF6 IOCF5 IOCF4 IOCF3 IOCF2 IOCF1 IOCF0
FD0h RCON IPEN —CM RI TO PD POR BOR
Legend:
— = unimplemented, read as ‘
0
’.
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PIC18F97J94 FAMILY
FCFh TMR1H Timer1 Register High Byte
FCEh TMR1L Timer1 Register Low Byte
FCDh T1CON TMR1CS1 TMR1CS0 T1CKPS1 T1CKPS0 SOSCEN T1SYNC RD16 TMR1ON
FCCh TMR2 Timer2 Register
FCBh PR2 Timer2 Period Register
FCAh T2CON — T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0
FC9h SSP1BUF MSSP1 Receive Buffer/Transmit Register
FC8h SSP1ADD MSSP1 Address Register in I
2
C™ Slave Mode. MSSP1 Baud Rate Reload Register in I
2
C Master Mode.
FC7h SSP1STAT SMP CKE D/A PSR/WUA BF
FC6h SSP1CON1 WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0
FC5h SSP1CON2 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN
FC4h CMSTAT — — — — — C3OUT C2OUT C1OUT
FC3h ADCBUF0H A/D Result Register 0 High Byte
FC2h ADCBUF0L A/D Result Register 0 Low Byte
FC1h ADCON1H ADON — — — — MODE12 FORM1 FORM0
FC0h ADCON1L SSRC3 SSRC2 SSRC1 SSRC0 — ASAM SAMP DONE
FBFh CVRCONH — — — CVR4 CVR3 CVR2 CVR1 CVR0
FBEh CVRCONL CVREN CVROE CVRPSS1 CVRPSS0 — — — CVRNSS
FBDh ECCP1AS ECCP1ASE ECCP1AS2 ECCP1AS1 ECCP1AS0 PSS1AC1 PSS1AC0 PSS1BD1 PSS1BD0
FBCh ECCP1DEL P1RSEN P1DC6 P1DC5 P1DC4 P1DC3 P1DC2 P1DC1 P1DC0
FBBh CCPR1H Capture/Compare/PWM Register1 High Byte
FBAh CCPR1L Capture/Compare/PWM Register1 Low Byte
FB9h CCP1CON P1M1 P1M0 CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0
FB8h PIR5 —ACTORSIF ACTLOCKIF TMR8IF — TMR6IF TMR5IF TMR4IF
FB7h PIE5 —ACTORSIE ACTLOCKIE TMR8IE — TMR6IE TMR5IE TMR4IE
FB6h IPR4 CCP10IP CCP9IP CCP8IP CCP7IP CCP6IP CCP5IP CCP4IP ECCP3IP
FB5h PIR4 CCP10IF CCP9IF CCP8IF CCP7IF CCP6IF CCP5IF CCP4IF ECCP3IF
FB4h PIE4 CCP10IE CCP9IE CCP8IE CCP7IE CCP6IE CCP5IE CCP4IE ECCP3IE
FB3h TMR3H Timer3 Register High Byte
FB2h TMR3L Timer3 Register Low Byte
FB1h T3CON TMR3CS1 TMR3CS0 T3CKPS1 T3CKPS0 SOSCEN T3SYNC RD16 TMR3ON
FB0h T3GCON TMR3GE T3GPOL T3GTM T3GSPM T3GGO/T3DONET3GVAL T3GSS1 T3GSS0
FAFh SPBRG1 EUSART1 Baud Rate Generator
FAEh RCREG1 EUSART1 Receive Register
FADh TXREG1 EUSART1 Transmit Register
FACh TXSTA1 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D
FABh RCSTA1 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
FAAh T1GCON TMR1GE T1GPOL T1GTM T1GSPM T1GGO/T1DONET1GVAL T1GSS1 T1GSS0
FA9h IPR6 RC4IP TX4IP RC3IP TX3IP — CMP3IP CMP2IP CMP1IP
FA8h HLVDCON VDIRMAG BGVST IRVST HLVDEN HLVDL3 HLVDL2 HLVDL1 HLVDL0
FA7h PSPCON IBF OBF IBOV PSPMODE — — — —
FA6h PIR6 RC4IF TX4IF RC3IF TX3IF — CMP3IF CMP2IF CMP1IF
FA5h IPR3 TMR5GIP LCDIP RC2IP TX2IP CTMUIP CCP2IP CCP1IP RTCCIP
FA4h PIR3 TMR5GIF LCDIF RC2IF TX2IF CTMUIF CCP2IF CCP1IF RTCCIF
FA3h PIE3 TMR5GIE LCDIE RC2IE TX2IE CTMUIE CCP2IE CCP1IE RTCCIE
FA2h IPR2 OSCFIP SSP2IP BCL2IP USBIP BCL1IP HLVDIP TMR3IP TMR3GIP
FA1h PIR2 OSCFIF SSP2IF BCL2IF USBIF BCL1IF HLVDIF TMR3IF TMR3GIF
FA0h PIE2 OSCFIE SSP2IE BCL2IE USBIE BCL1IE HLVDIE TMR3IE TMR3GIE
F9Fh IPR1 PSPIP ADIP RC1IP TX1IP SSP1IP TMR1GIP TMR2IP TMR1IP
F9Eh PIR1 PSPIF ADIF RC1IF TX1IF SSP1IF TMR1GIF TMR2IF TMR1IF
F9Dh PIE1 PSPIE ADIE RC1IE TX1IE SSP1IE TMR1GIE TMR2IE TMR1IE
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
PIC18F97J94 FAMILY
DS30575A-page 126 2012 Microchip Technology Inc.
F9Ch PSTR1CON CMPL1 CMPL0 — STRSYNC STRD STRC STRB STRA
F9Bh OSCTUNE —— TUN5 TUN4 TUN3 TUN2 TUN1 TUN0
F9Ah TRISJ TRISJ7 TRISJ6 TRISJ5 TRISJ4 TRISJ3 TRISJ2 TRISJ1 TRISJ0
F99h TRISH TRISH7 TRISH6 TRISH5 TRISH4 TRISH3 TRISH2 TRISH1 TRISH0
F98h TRISG TRISG7 TRISG6 — TRISG4 TRISG3 TRISG2 TRISG1 TRISG0
F97h TRISF TRISF7 TRISF6 TRISF5 TRISF4 TRISF3 TRISF2 — —
F96h TRISE TRISE7 TRISE6 TRISE5 TRISE4 TRISE3 TRISE2 TRISE1 TRISE0
F95h TRISD TRISD7 TRISD6 TRISD5 TRISD4 TRISD3 TRISD2 TRISD1 TRISD0
F94h TRISC TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0
F93h TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0
F92h TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0
F91h LATJ LATJ7 LATJ6 LATJ5 LATJ4 LATJ3 LATJ2 LATJ1 LATJ0
F90h LATH LATH7 LATH6 LATH5 LATH4 LATH3 LATH2 LATH1 LATH0
F8Fh LATG LATG7 LATG6 — LATG4 LATG3 LATG2 LATG1 LATG0
F8Eh LATF LATF7 LATF6 LATF5 LATF4 LATF3 LATF2 — —
F8Dh LATE LATE7 LATE6 LATE5 LATE4 LATE3 LATE2 LATE1 LATE0
F8Ch LATD LATD7 LATD6 LATD5 LATD4 LATD3 LATD2 LATD1 LATD0
F8Bh LATC LATC7 LATC6 LATC5 LATC4 LATC3 LATC2 LATC1 LATC0
F8Ah LATB LATB7 LATB6 LATB5 LATB4 LATB3 LATB2 LATB1 LATB0
F89h LATA LATA7 LATA6 LATA5 LATA4 LATA3 LATA2 LATA1 LATA0
F88h PORTJ RJ7 RJ6 RJ5 RJ4 RJ3 RJ2 RJ1 RJ0
F87h PORTH RH7 RH6 RH5 RH4 RH3 RH2 RH1 RH0
F86h PORTG RG7 RG6 — RG4 RG3 RG2 RG1 RG0
F85h PORTF RF7 RF6 RF5 RF4 RF3 RF2 — —
F84h PORTE RE7 RE6 RE5 RE4 RE3 RE2 RE1 RE0
F83h PORTD RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0
F82h PORTC RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0
F81h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0
F80h PORTA RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0
F7Fh EECON1 —— WWPROG FREE WRERR WREN WR —
F7Eh EECON2 EEPROM Control Register 2 (not a physical register)
F7Dh RCON2 EXTR —SWDTEN — — — — —
F7Ch RCON3 STKERR — — — VDDBOR VDDPOR VBPOR VBAT
F7Bh RCON4 — — —SRETEN —DPSLP—PMSLP
F7Ah UFRML FRM7 FRM6 FRM5 FRM4 FRM3 FRM2 FRM1 FRM0
F79h UFRMH — — — — — FRM10 FRM9 FRM8
F78h UIR — SOFIF STALLIF IDLEIF TRNIF ACTVIF UERRIF URSTIF
F77h UEIR BTSEF —— BTOEF DFN8EF CRC16EF CRC5EF PIDEF
F76H USTAT — ENDP3 ENDP2 ENDP1 ENDP0 DIR PPBI —
F75h UCON — PPBRST SE0 PKTDIS USBEN RESUME SUSPND —
F74h UADDR — ADDR6 ADDR5 ADDR4 ADDR3 ADDR2 ADDR1 ADDR0
F73h TRISVP TRISVP7 TRISVP6 TRISVP5 TRISVP4 TRISVP3 TRISVP2 TRISVP1 TRISVP0
F72h LATVP LATVP7 LATVP6 LATVP5 LATVP4 LATVP3 LATVP2 LATVP1 LATVP0
F71h PORTVP RVP7 RVP6 RVP5 RVP4 RVP3 RVP2 RVP1 RVP0
F70h TXADDRL SPI DMA Transmit Data Pointer Low Byte
F6Fh TXADDRH — — — — SPI DMA Transmit Data Pointer High Byte
F6Eh RXADDRL SPI DMA Receive Data Pointer Low Byte
F6Dh RXADDRH — — — — SPI DMA Receive Data Pointer High Byte
F6Ch DMABCL SPI DMA Byte Count Low Byte
F6Bh DMABCH — — — — — — SPI DMA Byte Count High Byte
F6Ah TXBUF TXBUF7 TXBUF6 TXBUF5 TXBUF4 TXBUF3 TXBUF2 TXBUF1 TXBUF0
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
2012 Microchip Technology Inc. DS30575A-page 127
PIC18F97J94 FAMILY
F69h SSP1CON3 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
F68h SSP1MSK MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0
F67h BAUDCON1 ABDOVF RCIDL RXDTP TXCKP BRG16 IREN WUE ABDEN
F66h OSCCON2 CLKLOCK IOLOCK LOCK — CF POSCEN SOSCGO —
F65h OSCCON3 — — — — — IRCF2 IRCF1 IRCF0
F64h OSCCON4 CPDIV1 CPDIV0 PLLEN — — — — —
F63h ACTCON ACTEN — ACTSIDL ACTSRC ACTLOCK ACTLOCKPOL ACTORS ACTORSPOL
F62h WPUB WPUB7 WPUB6 WPUB5 WPUB4 WPUB3 WPUB2 WPUB1 WPUB0
F61h PIE6 RC4IE TX4IE RC3IE TX3IE — CMP3IE CMP2IE CMP1IE
F60h DMACON1 SSCON1 SSCON0 TXINC RXINC DUPLEX1 DUPLEX0 DLYINTEN DMAEN
F5Fh RTCCON1 RTCEN — RTCWREN RTCSYNC HALFSEC RTCOE RTCPTR1 RTCPTR0
F5Eh RTCCAL CAL7 CAL6 CAL5 CAL4 CAL3 CAL2 CAL1 CAL0
F5Dh RTCVALH RTCC Value High Register Window Based on RTCPTR<1:0>
F5Ch RTCVALL RTCC Value Low Register Window Based on RTCPTR<1:0>
F5Bh ALRMCFG ALRMEN CHIME AMASK3 AMASK2 AMASK1 AMASK0 ALRMPTR1 ALRMPTR0
F5Ah ALRMRPT ARPT7 ARPT6 ARPT5 ARPT4 ARPT3 ARPT2 ARPT1 ARPT0
F59h ALRMVALH Alarm Value High Register Window Based on APTR<1:0>
F58h ALRMVALL Alarm Value Low Register Window Based on APTR<1:0>
F57h RTCCON2 PWCEN PWCPOL PWCCPRE PWCSPRE RTCCLKSEL1 RTCCLKSEL0 RTCSECSEL1 RTCSECSEL0
F56h IOCP IOCP7 IOCP6 IOCP5 IOCP4 IOCP3 IOCP2 IOCP1 IOCP0
F55h IOCN IOCN7 IOCN6 IOCN5 IOCN4 IOCN3 IOCN2 IOCN1 IOCN0
F54h PADCFG1 RDPU REPU RFPU RGPU RHPU RJPU RKPU RLPU
F53h CM1CON CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0
F52h ECCP2AS ECCP2ASE ECCP2AS2 ECCP2AS1 ECCP2AS0 PSS2AC1 PSS2AC0 PSS2BD1 PSS2BD0
F51h ECCP2DEL P2RSEN P2DC6 P2DC5 P2DC4 P2DC3 P2DC2 P2DC1 P2DC0
F50h CCPR2H Capture/Compare/PWM Register 1 High Byte
F4Fh CCPR2L Capture/Compare/PWM Register 1 Low Byte
F4Eh CCP2CON P2M1 P2M0 CCP2X CCP2Y CCP2M3 CCP2M2 CCP2M1 CCP2M0
F4Dh ECCP3AS ECCP3ASE ECCP3AS2 ECCP3AS1 ECCP3AS0 PSS3AC1 PSS3AC0 PSS3BD1 PSS3BD0
F4Ch ECCP3DEL P3RSEN P3DC6 P3DC5 P3DC4 P3DC3 P3DC2 P3DC1 P3DC0
F4Bh CCPR3H Capture/Compare/PWM Register 1 High Byte
F4Ah CCPR3L Capture/Compare/PWM Register 1 Low Byte
F49H CCP3CON P3M1 P3M0 CCP3X CCP3Y CCP3M3 CCP3M2 CCP3M1 CCP3M0
F48h CCPR8H Capture/Compare/PWM Register 8 High Byte
F47h CCPR8L Capture/Compare/PWM Register 8 Low Byte
F46h CCP8CON —— CCP8X CCP8Y CCP8M3 CCP8M2 CCP8M1 CCP8M0
F45h CCPR9H Capture/Compare/PWM Register 9 High Byte
F44h CCPR9L Capture/Compare/PWM Register 9 Low Byte
F43h CCP9CON —— CCP9X CCP9Y CCP9M3 CCP9M2 CCP9M1 CCP9M0
F42h CCPR10H Capture/Compare/PWM Register 10 High Byte
F41h CCPR10L Capture/Compare/PWM Register 10 Low Byte
F40h CCP10CON —— CCP10X CCP10Y CCP10M3 CCP10M2 CCP10M1 CCP10M0
F3Fh TMR6 Timer6 Register
F3Eh PR6 Timer6 Period Register
F3Dh T6CON — T6OUTPS3 T6OUTPS2 T6OUTPS1 T6OUTPS0 TMR6ON T6CKPS1 T6CKPS0
F3Ch TMR8 Timer8 Register
F3Bh PR8 Timer8 Period Register
F3Ah T8CON — T8OUTPS3 T8OUTPS2 T8OUTPS1 T8OUTPS0 TMR8ON T8CKPS1 T8CKPS0
F39H SSP2CON3 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
F38h CM2CON CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0
F37h CM3CON CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
PIC18F97J94 FAMILY
DS30575A-page 128 2012 Microchip Technology Inc.
F36h CCPTMRS0 C3TSEL1 C3TSEL0 C2TSEL2 C2TSEL1 C2TSEL0 C1TSEL2 C1TSEL1 C1TSEL0
F35h CCPTMRS1 C7TSEL1 C7TSEL0 — C6TSEL0 — C5TSEL0 C4TSEL1 C4TSEL0
F34h CCPTMRS2 — — —C10TSEL0 — C9TSEL0 C8TSEL1 C8TSEL0
F33h RCSTA2 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
F32h TXSTA2 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D
F31h BAUDCON2 ABDOVF RCIDL RXDTP TXCKP BRG16 IREN WUE ABDEN
F30h SPBRGH1 EUSART1 Baud Rate Generator High Byte
F2Fh RCSTA3 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
F2Eh TXSTA3 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D
F2Dh BAUDCON3 ABDOVF RCIDL RXDTP TXCKP BRG16 IREN WUE ABDEN
F2Ch SPBRGH3 EUSART3 Baud Rate Generator High Byte
F2Bh SPBRG3 EUSART3 Baud Rate Generator
F2Ah RCREG3 EUSART3 Receive Data FIFO
F29H TXREG3 EUSART3 Transmit Data FIFO
F28h DSCONL — — — — — ULPWDIS DSBOR RELEASE
F27h DSCONH DSEN — — — — — —RTCWDIS
F26h DSWAKEL DSFLT BOR DSULP DSWDT DSRTC DSMCLR DSICD DSPOR
F25h DSWAKEH — — — — — — —DSINT0
F24h DSGPR0 Deep Sleep General Purpose Register 0
F23h DSGPR1 Deep Sleep General Purpose Register 1
F22h DSGPR2 Deep Sleep General Purpose Register 2
F21h DSGPR3 Deep Sleep General Purpose Register 3
F20h SPBRGH2 EUSART2 Baud Rate Generator High Byte
F1Fh SPBRG2 EUSART2 Baud Rate Generator
F1Eh RCREG2 Receive Data FIFO
F1Dh TXREG2 Transmit Data FIFO
F1Ch PSTR2CON CMPL1 CMPL0 — STRSYNC STRD STRC STRB STRA
F1Bh PSTR3CON CMPL1 CMPL0 — STRSYNC STRD STRC STRB STRA
F1Ah SSP2STAT SMP CKE D/A PSR/WUA BF
F19h SSP2CON1 WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0
F18h SSP2CON2 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN
F17h SSP2MSK MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0
F16h TMR5H Timer5 Register High Byte
F15h TMR5L Timer5 Register Low Byte
F14h T5CON TMR5CS1 TMR5CS0 T5CKPS1 T5CKPS0 SOSCEN T5SYNC RD16 TMR5ON
F13h T5GCON TMR5GE T5GPOL T5GTM T5GSPM T5GGO/T5DONET5GVAL T5GSS1 T5GSS0
F12h CCPR4H Capture/Compare/PWM Register 4 High Byte
F11h CCPR4L Capture/Compare/PWM Register 4 Low Byte
F10h CCP4CON —— DC4B1 DC4B0 CCP4M3 CCP4M2 CCP4M1 CCP4M0
F0Fh CCPR5H Capture/Compare/PWM Register 5 High Byte
F0Eh CCPR5L Capture/Compare/PWM Register 5 Low Byte
F0Dh CCP5CON —— DC5B1 DC5B0 CCP5M3 CCP5M2 CCP5M1 CCP5M0
F0Ch CCPR6H Capture/Compare/PWM Register 6 High Byte
F0Bh CCPR6L Capture/Compare/PWM Register 6 Low Byte
F0Ah CCP6CON —— DC6B1 DC6B0 CCP6M3 CCP6M2 CCP6M1 CCP6M0
F09h CCPR7H Capture/Compare/PWM Register 7 High Byte
F08h CCPR7L Capture/Compare/PWM Register 7 Low Byte
F07h CCP7CON —— DC7B1 DC7B0 CCP7M3 CCP7M2 CCP7M1 CCP7M0
F06h TMR4 Timer4 Register
F05h PR4 Timer4 Period Register
F04h T4CON — T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
2012 Microchip Technology Inc. DS30575A-page 129
PIC18F97J94 FAMILY
F03h SSP2BUF MSSP2 Receive Buffer/Transmit Register
F02h SSP2ADD MSSP2 Address Register in I
2
C™ Slave Mode. MSSP1 Baud Rate Reload Register in I
2
C Master Mode.
F01h ANCFG — — — — — VBG6EN VBG2EN VBGEN
F00h DMACON2 DLYCYC3 DLYCYC2 DLYCYC1 DLYCYC0 INTLVL3 INTLVL2 INTLVL1 INTLVL0
EFFh RCSTA4 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
EFEh TXSTA4 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D
EFDh BAUDCON4 ABDOVF RCIDL RXDTP TXCKP BRG16 IREN WUE ABDEN
EFCh SPBRGH4 EUSART4 Baud Rate Generator High Byte
EFBh SPBRG4 EUSART4 Baud Rate Generator
EFAh RCREG4 EUSART4 Receive Data FIFO
EF9h TXREG4 EUSART4 Transmit Data FIFO
EF8h CTMUCON1 CTMUEN — CTMUSIDL TGEN EDGEN EDGSEQEN IDISSEN TRIGEN
EF7h CTMUCON2 ITRIM5 ITRIM4 ITRIM3 ITRIM2 ITRIM1 ITRIM0 IRNG1 IRNG0
EF6h CTMUCON3 EDG2EN EDG2POL EDG2SEL3 EDG2SEL2 EDG2SEL1 EDG2SEL0 — —
EF5h CTMUCON4 EDG1EN EDG1POL EDG1SEL3 EDG1SEL2 EDG1SEL1 EDG1SEL0 EDG2STAT EDG1STAT
EF4h PMD0 CCP10MD CCP9MD CCP8MD CCP7MD CCP6MD CCP5MD CCP4MD ECCP3MD
EF3h PMD1 ECCP2MD ECCP1MD UART4MD UART3MD UART2MD UART1MD SSP2MD SSP1MD
EF2h PMD2 TMR8MD TMR6MD TMR5MD TMR4MD TMR3MD TMR2MD TMR1MD TMR0MD
EF1h PMD3 TXMMD CTMUMD ADCMD RTCCMD LCDMD PSPMD REFO1MD REFO2MD
EF0h PMD4 CMP1MD CMP2MD CMP3MD USBMD IOCMD LVDMD —EMBMD
EEFh MDCON MDEN MDOE MDSLR MDOPOL MDO ——MDBIT
EEEh MDSRC MDSODIS — — — MDSRC3 MDSRC2 MDSRC1 MDSRC0
EEDh MDCARH MDCHODIS MDCHPOL MDCHSYNC — MDCH3 MDCH2 MDCH1 MDCH0
EECh MDCARL MDCLODIS MDCLPOL MDCLSYNC — MDCL3 MDCL2 MDCL1 MDCL0
EEBh ODCON1 ECCP2OD ECCP1OD USART4OD USART3OD USART2OD USART1OD SSP2OD SSP1OD
EEAh ODCON2 CCP10OD CCP9OD CCP8OD CCP7OD CCP6OD CCP5OD CCP4OD ECCP3OD
EE9h TRISK TRISK7 TRISK6 TRISK5 TRISK4 TRISK3 TRISK2 TRISK1 TRISK0
EE8h LATK LATK7 LATK6 LATK5 LATK4 LATK3 LATK2 LATK1 LATK0
EE7h PORTK RK7 RK6 RK5 RK4 RK3 RK2 RK1 RK0
EE6h TRISL TRISL7 TRISL6 TRISL5 TRISL4 TRISL3 TRISL2 TRISL1 TRISL0
EE5h LATL LATL7 LATL6 LATL5 LATL4 LATL3 LATL2 LATL1 LATL0
EE4h PORTL RL7 RL6 RL5 RL4 RL3 RL2 RL1 RL0
EE3h MEMCON EBDIS —WAIT1WAIT0 ——WM1WM0
EE2h REFO1CON ON —SIDL OE RSLP — DIVSWEN ACTIVE
EE1h REFO1CON1 — — — — ROSEL3 ROSEL2 ROSEL1 ROSEL0
EE0h REFO1CON2 RODIV7 RODIV6 RODIV5 RODIV4 RODIV3 RODIV2 RODIV1 RODIV0
EDFh REFO1CON3 — RODIV14 RODIV13 RODIV12 RODIV11 RODIV10 RODIV9 RODIV8
EDEh REFO2CON ON —SIDL OE RSLP — DIVSWEN ACTIVE
EDDh REFO2CON1 — — — — ROSEL3 ROSEL2 ROSEL1 ROSEL0
EDCh REFO2CON2 RODIV7 RODIV6 RODIV5 RODIV4 RODIV3 RODIV2 RODIV1 RODIV0
EDBh REFO2CON3 — RODIV14 RODIV13 RODIV12 RODIV11 RODIV10 RODIV9 RODIV8
EDAh LCDPS WFT BIASMD LCDA WA LP3 LP2 LP1 LP0
ED9h LCDCON LCDEN SLPEN WERR CS1 CS0 LMUX2 LMUX1 LMUX0
ED8h LCDREG CPEN — BIAS2 BIAS1 BIAS0 MODE13 CLKSEL1 CLKSEL0
ED7h LCDREF LCDIRE — LCDCST2 LCDCST1 LCDCST0 VLCD3PE VLCD2PE VLCD1PE
ED6h LCDRL LRLAP1 LRLAP0 LRLBP1 LRLBP0 — LRLAT2 LRLAT1 LRLAT0
ED5h LCDSE7 SE63 SE62 SE61 SE60 SE59 SE58 SE57 SE56
ED4h LCDSE6 SE55 SE54 SE53 SE52 SE51 SE50 SE49 SE48
ED3h LCDSE5 SE47 SE46 SE45 SE44 SE43 SE42 SE41 SE40
ED2h LCDSE4 SE39 SE38 S37 SE36 SE35 SE34 SE33 SE32
ED1h LCDSE3 SE31 SE30 SE29 SE28 SE27 SE26 SE25 SE24
ED0h LCDSE2 SE23 SE22 SE21 SE20 SE19 SE18 SE17 SE16
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
PIC18F97J94 FAMILY
DS30575A-page 130 2012 Microchip Technology Inc.
ECFh LCDSE1 SE15 SE14 SE13 SE12 SE11 SE10 SE09 SE08
ECEh LCDSE0 SE07 SE06 SE05 SE04 SE03 SE02 SE01 SE00
ECDh LCDDATA63 S63C7 S62C7 S61C7 S60C7 S59C7 S58C7 S57C7 S56C7
ECCh LCDDATA62 S55C7 S54C7 S53C7 S52C7 S51C7 S50C7 S49C7 S48C7
ECBh LCDDATA61 S47C7 S46C7 S45C7 S44C7 S43C7 S42C7 S41C7 S40C7
ECAh LCDDATA60 S39C7 S38C7 S37C7 S36C7 S35C7 S34C7 S33C7 S32C7
EC9h LCDDATA59 S31C7 S30C7 S29C7 S28C7 S27C7 S26C7 S25C7 S24C7
EC8h LCDDATA58 S23C7 S22C7 S21C7 S20C7 S19C7 S18C7 S17C7 S16C7
EC7h LCDDATA57 S15C7 S14C7 S13C7 S12C7 S11C7 S10C7 S09C7 S08C7
EC6h LCDDATA56 S07C7 S06C7 S05C7 S04C7 S03C7 S02C7 S01C7 S00C7
EC5h LCDDATA55 S63C6 S62C6 S61C6 S60C6 S59C6 S58C6 S57C6 S56C6
EC4h LCDDATA54 S55C6 S54C6 S53C6 S52C6 S51C6 S50C6 S49C6 S48C6
EC3h LCDDATA53 S47C6 S46C6 S45C6 S44C6 S43C6 S42C6 S41C6 S40C6
EC2h LCDDATA52 S39C6 S38C6 S37C6 S36C6 S35C6 S34C6 S33C6 S32C6
EC1h LCDDATA51 S31C6 S30C6 S29C6 S28C6 S27C6 S26C6 S25C6 S24C6
EC0h LCDDATA50 S23C6 S22C6 S21C6 S20C6 S19C6 S18C6 S17C6 S16C6
EBFh LCDDATA49 S15C6 S14C6 S13C6 S12C6 S11C6 S10C6 S09C6 S08C6
EBEh LCDDATA48 S07C6 S06C6 S05C6 S04C6 S03C6 S02C6 S01C6 S00C6
EBDh LCDDATA47 S63C5 S62C5 S61C5 S60C5 S59C5 S58C5 S57C5 S56C5
EBCh LCDDATA46 S55C5 S54C5 S53C5 S52C5 S51C5 S50C5 S49C5 S48C5
EBBh LCDDATA45 S47C5 S46C5 S45C5 S44C5 S43C5 S42C5 S41C5 S40C5
EBAh LCDDATA44 S39C5 S38C5 S37C5 S36C5 S35C5 S34C5 S33C5 S32C5
EB9h LCDDATA43 S31C5 S30C5 S29C5 S28C5 S27C5 S26C5 S25C5 S24C5
EB8h LCDDATA42 S23C5 S22C5 S21C5 S20C5 S19C5 S18C5 S17C5 S16C5
EB7h LCDDATA41 S15C5 S14C5 S13C5 S12C5 S11C5 S10C5 S09C5 S08C5
EB6h LCDDATA40 S07C5 S06C5 S05C5 S04C5 S03C5 S02C5 S01C5 S00C5
EB5h LCDDATA39 S63C4 S62C4 S61C4 S60C4 S59C4 S58C4 S57C4 S56C4
EB4h LCDDATA38 S55C4 S54C4 S53C4 S52C4 S51C4 S50C4 S49C4 S48C4
EB3h LCDDATA37 S47C4 S46C4 S45C4 S44C4 S43C4 S42C4 S41C4 S40C4
EB2h LCDDATA36 S39C4 S38C4 S37C4 S36C4 S35C4 S34C4 S33C4 S32C4
EB1h LCDDATA35 S31C4 S30C4 S29C4 S28C4 S27C4 S26C4 S25C4 S24C4
EB0h LCDDATA34 S23C4 S22C4 S21C4 S20C4 S19C4 S18C4 S17C4 S16C4
EAFh LCDDATA33 S15C4 S14C4 S13C4 S12C4 S11C4 S10C4 S09C4 S08C4
EAEh LCDDATA32 S07C4 S06C4 S05C4 S04C4 S03C4 S02C4 S01C4 S00C4
EADh LCDDATA31 S63C3 S62C3 S61C3 S60C3 S59C3 S58C3 S57C3 S56C3
EACh LCDDATA30 S55C3 S54C3 S53C3 S52C3 S51C3 S50C3 S49C3 S48C3
EABh LCDDATA29 S47C3 S46C3 S45C3 S44C3 S43C3 S42C3 S41C3 S40C3
EAAh LCDDATA28 S39C3 S38C3 S37C3 S36C3 S35C3 S34C3 S33C3 S32C3
EA9h LCDDATA27 S31C3 S30C3 S29C3 S28C3 S27C3 S26C3 S25C3 S24C3
EA8h LCDDATA26 S23C3 S22C3 S21C3 S20C3 S19C3 S18C3 S17C3 S16C3
EA7h LCDDATA25 S15C3 S14C3 S13C3 S12C3 S11C3 S10C3 S09C3 S08C3
EA6h LCDDATA24 S07C3 S06C3 S05C3 S04C3 S03C3 S02C3 S01C3 S00C3
EA5h LCDDATA23 S63C2 S62C2 S61C2 S60C2 S59C2 S58C2 S57C2 S56C2
EA4h LCDDATA22 S55C2 S54C2 S53C2 S52C2 S51C2 S50C2 S49C2 S48C2
EA3h LCDDATA21 S47C2 S46C2 S45C2 S44C2 S43C2 S42C2 S41C2 S40C2
EA2h LCDDATA20 S39C2 S38C2 S37C2 S36C2 S35C2 S34C2 S33C2 S32C2
EA1h LCDDATA19 S31C2 S30C2 S29C2 S28C2 S27C2 S26C2 S25C2 S24C2
EA0h LCDDATA18 S23C2 S22C2 S21C2 S20C2 S19C2 S18C2 S17C2 S16C2
E9Fh LCDDATA17 S15C2 S14C2 S13C2 S12C2 S11C2 S10C2 S09C2 S08C2
E9Eh LCDDATA16 S07C2 S06C2 S05C2 S04C2 S03C2 S02C2 S01C2 S00C2
E9Dh LCDDATA15 S63C1 S62C1 S61C1 S60C1 S59C1 S58C1 S57C1 S56C1
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
2012 Microchip Technology Inc. DS30575A-page 131
PIC18F97J94 FAMILY
E9Ch LCDDATA14 S55C1 S54C1 S53C1 S52C1 S51C1 S50C1 S49C1 S48C1
E9Bh LCDDATA13 S47C1 S46C1 S45C1 S44C1 S43C1 S42C1 S41C1 S40C1
E9Ah LCDDATA12 S39C1 S38C1 S37C1 S36C1 S35C1 S34C1 S33C1 S32C1
E99h LCDDATA11 S31C1 S30C1 S29C1 S28C1 S27C1 S26C1 S25C1 S24C1
E98h LCDDATA10 S23C1 S22C1 S21C1 S20C1 S19C1 S18C1 S17C1 S16C1
E97h LCDDATA9 S15C1 S14C1 S13C1 S12C1 S11C1 S10C1 S09C1 S08C1
E96h LCDDATA8 S07C1 S06C1 S05C1 S04C1 S03C1 S02C1 S01C1 S00C1
E95h LCDDATA7 S63C0 S62C0 S61C0 S60C0 S59C0 S58C0 S57C0 S56C0
E94h LCDDATA6 S55C0 S54C0 S53C0 S52C0 S51C0 S50C0 S49C0 S48C0
E93h LCDDATA5 S47C0 S46C0 S45C0 S44C0 S43C0 S42C0 S41C0 S40C0
E92h LCDDATA4 S39C0 S38C0 S37C0 S36C0 S35C0 S34C0 S33C0 S32C0
E91h LCDDATA3 S31C0 S30C0 S29C0 S28C0 S27C0 S26C0 S25C0 S24C0
E90h LCDDATA2 S23C0 S22C0 S21C0 S20C0 S19C0 S18C0 S17C0 S16C0
E8Fh LCDDATA1 S15C0 S14C0 S13C0 S12C0 S11C0 S10C0 S09C0 S08C0
E8Eh LCDDATA0 S07C0 S06C0 S05C0 S04C0 S03C0 S02C0 S01C0 S00C0
E8Dh ADCON2H PVCFG1 PVCFG0 NVCFG0 OFFCAL BUFREGEN CSCNA — —
E8Ch ADCON2L BUFS SMPI4 SMPI3 SMPI2 SMPI1 SMPI0 BUFM ALTS
E8Bh ADCON3H ADRC EXTSAM PUMPEN SAMC4 SAMC3 SAMC2 SAMC1 SAMC0
E8Ah ADCON3L ADCS7 ADCS6 ADCS5 ADCS4 ADCS3 ADCS2 ADCS1 ADCS0
E89h ADCON5H ASENA LPENA CTMUREQ — — — ASINTMD1 ASINTMD0
E88h ADCON5L — — — —WM1WM0CM1CM0
E87h ADCHS0H CH0NB2 CH0NB1 CH0NB0 CH0SB4 CH0SB3 CH0SB2 CH0SB1 CH0SB0
E86h ADCHS0L CH0NA2 CH0NA1 CH0NA0 CH0SA4 CH0SA3 CH0SA2 CH0SA1 CH0SA0
E85h ADCSS1H — CSS30 CSS29 CSS28 CSS27 CSS26 CSS25 CSS24
E84h ADCSS1L CSS23 CSS22 CSS21 CSS20 CSS19 CSS18 CSS17 CSS16
E83h ADCSS0H CSS15 CSS14 CSS13 CSS12 CSS11 CSS10 CSS9 CSS8
E82h ADCSS0L CSS7 CSS6 CSS5 CSS4 CSS3 CSS2 CSS1 CSS0
E81h ADCHIT1H — CHH30 CHH29 CHH28 CHH27 CHH26 CHH25 CHH24
E80h ADCHIT1L CHH23 CHH22 CHH21 CHH20 CHH19 CHH18 CHH17 CHH16
E7Fh ADCHIT0H CHH15 CHH14 CHH13 CHH12 CHH11 CHH10 CHH9 CHH8
E7Eh ADCHIT0L CHH7 CHH6 CHH5 CHH4 CHH3 CHH2 CHH1 CHH0
E7Dh ADCTMUEN1H — CTMUEN30 CTMUEN29 CTMUEN28 CTMUEN27 CTMUEN26 CTMUEN25 CTMUEN24
E7Ch ADCTMUEN1L CTMUEN23 CTMUEN22 CTMUEN21 CTMUEN20 CTMUEN19 CTMUEN18 CTMUEN17 CTMUEN16
E7Bh ADCTMUEN0H CTMUEN15 CTMUEN14 CTMUEN13 CTMUEN12 CTMUEN11 CTMUEN10 CTMUEN9 CTMUEN8
E7Ah ADCTMUEN0L CTMUEN7 CTMUEN6 CTMUEN5 CTMUEN4 CTMUEN3 CTMUEN2 CTMUEN1 CTMUEN0
E79h ADCBUF25H A/D Result Register 25 High Byte
E78h ADCBUF25L A/D Result Register 25 Low Byte
E77h ADCBUF24H A/D Result Register 24 High Byte
E76h ADCBUF24L A/D Result Register 24 Low Byte
E75h ADCBUF23H A/D Result Register 23 High Byte
E74h ADCBUF23L A/D Result Register 23 Low Byte
E73h ADCBUF22H A/D Result Register 22 High Byte
E72h ADCBUF22L A/D Result Register 22 Low Byte
E71h ADCBUF21H A/D Result Register 21 High Byte
E70h ADCBUF21L A/D Result Register 21 Low Byte
E6Fh ADCBUF20H A/D Result Register 20 High Byte
E6Eh ADCBUF20L A/D Result Register 20 Low Byte
E6Dh ADCBUF19H A/D Result Register 19 High Byte
E6Ch ADCBUF19L A/D Result Register 19 Low Byte
E6Bh ADCBUF18H A/D Result Register 18 High Byte
E6Ah ADCBUF18L A/D Result Register 18 Low Byte
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
PIC18F97J94 FAMILY
DS30575A-page 132 2012 Microchip Technology Inc.
E69h ADCBUF17H A/D Result Register 17 High Byte
E68h ADCBUF17L A/D Result Register 17 Low Byte
E67h ADCBUF16H A/D Result Register 16 High Byte
E66h ADCBUF16L A/D Result Register 16 Low Byte
E65h ADCBUF15H A/D Result Register 15 High Byte
E64h ADCBUF15L A/D Result Register 15 Low Byte
E63h ADCBUF14H A/D Result Register 14 High Byte
E62h ADCBUF14L A/D Result Register 14 Low Byte
E61h ADCBUF13H A/D Result Register 13 High Byte
E60h ADCBUF13L A/D Result Register 13 Low Byte
E5Fh ADCBUF12H A/D Result Register 12 High Byte
E5Eh ADCBUF12L A/D Result Register 12 Low Byte
E5Dh ADCBUF11H A/D Result Register 11 High Byte
E5Ch ADCBUF11L A/D Result Register 11 Low Byte
E5Bh ADCBUF10H A/D Result Register 10 High Byte
E5Ah ADCBUF10L A/D Result Register 10 Low Byte
E59h ADCBUF9H A/D Result Register 9 High Byte
E58h ADCBUF9L A/D Result Register 9 Low Byte
E57h ADCBUF8H A/D Result Register 8 High Byte
E56h ADCBUF8L A/D Result Register 8 Low Byte
E55h ADCBUF7H A/D Result Register 7 High Byte
E54h ADCBUF7L A/D Result Register 7 Low Byte
E53h ADCBUF6H A/D Result Register 6 High Byte
E52h ADCBUF6L A/D Result Register 6 Low Byte
E51h ADCBUF5H A/D Result Register 5 High Byte
E50h ADCBUF5L A/D Result Register 5 Low Byte
E4Fh ADCBUF4H A/D Result Register 4 High Byte
E4Eh ADCBUF4L A/D Result Register 4 Low Byte
E4Dh ADCBUF3H A/D Result Register 3 High Byte
E4Ch ADCBUF3L A/D Result Register 3 Low Byte
E4Bh ADCBUF2H A/D Result Register 2 High Byte
E4Ah ADCBUF2L A/D Result Register 2 Low Byte
E49h ADCBUF1H A/D Result Register 1 High Byte
E48h ADCBUF1L A/D Result Register 1 Low Byte
E47h ANCON1 ANSEL7 ANSEL6 ANSEL5 ANSEL4 ANSEL3 ANSEL2 ANSEL1 ANSEL0
E46h ANCON2 ANSEL15 ANSEL14 ANSEL13 ANSEL12 ANSEL11 ANSEL10 ANSEL9 ANSEL8
E45h ANCON3 ANSEL23 ANSEL22 ANSEL21 ANSEL20 ANSEL19 ANSEL18 ANSEL17 ANSEL16
E44h RPINR52_53 PBIO7R<3:0> PBIO6R<3:0>
E43h RPINR50_51 PBIO5R<3:0> PBIO4R<3:0>
E42h RPINR48_49 PBIO3R<3:0> PBIO2R<3:0>
E41h RPINR46_47 PBIO1R<3:0> PBIO0R<3:0>
E40h RPINR44_45 T5CKIR<3:0> T5GR<3:0>
E3Fh RPINR42_43 T3CKIR<3:0> T3GR<3:0>
E3Eh RPINR40_41 T1CKIR<3:0> T1GR<3:0>
E3Dh RPINR38_39 T0CKIR<3:0> CCP10R<3:0>
E3Ch RPINR36_37 CCP9R<3:0> CCP8R<3:0>
E3Bh RPINR34_35 CCP7R<3:0> CCP6R<3:0>
E3Ah RPINR32_33 CCP5R<3:0> CCP4R<3:0>
E39h RPINR30_31 MDCIN2R<3:0> MDCIN1R<3:0>
E38h RPINR28_29 MDMINR<3:0> INT3R<3:0>
E37h RPINR26_27 INT2R<3:0> INT1R<3:0>
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
2012 Microchip Technology Inc. DS30575A-page 133
PIC18F97J94 FAMILY
E36h RPINR24_25 IOC7R<3:0> IOC6R<3:0>
E35h RPINR22_23 IOC5R<3:0> IOC4R<3:0>
E34h RPINR20_21 IOC3R<3:0> IOC2R<3:0>
E33h RPINR18_19 IOC1R<3:0> IOC0R<3:0>
E32h RPINR16_17 ECCP3R<3:0> ECCP2R<3:0>
E31h RPINR14_15 ECCP1R<3:0> FLT0R<3:0>
E30h RPINR12_13 SS2R<3:0> SDI2R<3:0>
E2Fh RPINR10_11 SCK2R<3:0> SS1R<3:0>
E2Eh RPINR8_9 SDI1R<3:0> SCK1R<3:0>
E2Dh RPINR6_7 U4TXR<3:0> U4RXR<3:0>
E2Ch RPINR4_5 U3TXR<3:0> U3RXR<3:0>
E2Bh RPINR2_3 U2TXR<3:0> U2RXR<3:0>
E2Ah RPINR0_1 U1TXR<3:0> U1RXR<3:0>
E29h RPOR46 — — — — RPO46R<3:0>
E28h RPOR44_45 RPO45R<3:0> RPO44R<3:0>
E27h RPOR42_43 RPO43R<3:0> RPO42R<3:0>
E26h RPOR40_41 RPO41R<3:0> RPO40R<3:0>
E25h RPOR38_39 RPO39R<3:0> RPO38R<3:0>
E24h RPOR36_37 RPO37R<3:0> RPO36R<3:0>
E23h RPOR34_35 RPO35R<3:0> RPO34R<3:0>
E22h RPOR32_33 RPO33R<3:0> RPO32R<3:0>
E21h RPOR30_31 RPO31R<3:0> RPO30R<3:0>
E20h RPOR28_29 RPO29R<3:0> RPO28R<3:0>
E1Fh RPOR26_27 RPO27R<3:0> RPO26R<3:0>
E1Eh RPOR24_25 RPO25R<3:0> RPO24R<3:0>
E1Dh RPOR22_23 RPP23R<3:0> RPO22R<3:0>
E1Ch RPOR20_21 RPO21R<3:0> RPO20R<3:0>
E1Bh RPOR18_19 RPO19R<3:0> RPO18R<3:0>
E1Ah RPOR16_17 RPO17R<3:0> RPO16R<3:0>
E19h RPOR14_15 RPO15R<3:0> RPO14R<3:0>
E18h RPOR12_13 RPO13R<3:0> RPO12R<3:0>
E17h RPOR10_11 RPO11R<3:0> RPO10R<3:0>
E16h RPOR8_9 RPO9R<3:0> RPO8R<3:0>
E15h RPOR6_7 RPO7R<3:0> RPO6R<3:0>
E14h RPOR4_5 RPO5R<3:0> RPO4R<3:0>
E13h RPOR2_3 RPO3R<3:0> RPO2R<3:0>
E12h RPOR0_1 RPO1R<3:0> RPO0R<3:0>
E11h UCFG UTEYE UOEMON — UPUEN UTRDIS FSEN PPB1 PPB0
E10h UIE — SOFIE STALLIE IDLEIE TRNIE ACTVIE UERRIE URSTIE
E0Fh UEIE BTSEE —— BTOEE DFN8EE CRC16EE CRC5EE PIDEE
E0Eh UEP15 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E0Dh UEP14 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E0Ch UEP13 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E0Bh UEP12 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E0Ah UEP11 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E09h UEP10 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E08h UEP9 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E07h UEP8 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E06h UEP7 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E05h UEP6 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E04h UEP5 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
PIC18F97J94 FAMILY
DS30575A-page 134 2012 Microchip Technology Inc.
E03h UEP4 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E02h UEP3 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E01h UEP2 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
E00h UEP1 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
DFFh UEP0 — — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
DFEh Unimplemented — — — — — — — —
DFDh Unimplemented — — — — — — — —
DFCh Unimplemented — — — — — — — —
DFBh Unimplemented — — — — — — — —
DFAh Unimplemented — — — — — — — —
TABLE 6-2: REGISTER FILE SUMMARY (CONTINUED)
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Legend:
— = unimplemented, read as ‘
0
’.
2012 Microchip Technology Inc. DS30575A-page 135
PIC18F97J94 FAMILY
6.3.5 STATUS REGISTER
The STATUS register, shown in Register 6-2, contains
the arithmetic status of the ALU. The STATUS register
can be the operand for any instruction, as with any
other register. If the STATUS register is the destination
for an instruction that affects the Z, DC, C, OV or N bits,
the write to these five bits is disabled.
These bits are set or cleared according to the device
logic. Therefore, the result of an instruction with the
STATUS register as destination may be different than
intended. For example, CLRF STATUS will set the Z bit
but leave the other bits unchanged. The STATUS
register then reads back as ‘000u u1uu’.
It is recommended, therefore, that only BCF, BSF,
SWAPF, MOVFF and MOVWF instructions be used to
alter the STATUS register because these instructions
do not affect the Z, C, DC, OV or N bits in the STATUS
register.
For other instructions not affecting any Status bits, see
the instruction set summaries in Table 29-2 and
Table 29-3.
Note: The C and DC bits operate, in subtraction,
as borrow and digit borrow bits, respectively.
REGISTER 6-2: STATUS REGISTER
U-0 U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-x
— — —NOVZDC
(1)C(2)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘0’
bit 4 N: Negative bit
This bit is used for signed arithmetic (2’s complement). It indicates whether the result was negative
(ALU MSB = 1).
1 = Result was negative
0 = Result was positive
bit 3 OV: Overflow bit
This bit is used for signed arithmetic (2’s complement). It indicates an overflow of the seven-bit
magnitude which causes the sign bit (bit 7) to change state.
1 = Overflow occurred for signed arithmetic (in this arithmetic operation)
0 = No overflow occurred
bit 2 Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
bit 1 DC: Digit Carry/Borrow bit(1)
For ADDWF, ADDLW, SUBLW and SUBWF instructions:
1 = A carry-out from the 4th low-order bit of the result occurred
0 = No carry-out from the 4th low-order bit of the result
bit 0 C: Carry/Borrow bit(2)
For ADDWF, ADDLW, SUBLW and SUBWF instructions:
1 = A carry-out from the Most Significant bit of the result occurred
0 = No carry-out from the Most Significant bit of the result occurred
Note 1: For borrow, the polarity is reversed. A subtraction is executed by adding the 2’s complement of the second
operand. For rotate (RRF, RLF) instructions, this bit is loaded with either bit 4 or bit 3 of the source register.
2: For borrow, the polarity is reversed. A subtraction is executed by adding the 2’s complement of the second
operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high or low-order bit of the
source register.
PIC18F97J94 FAMILY
DS30575A-page 136 2012 Microchip Technology Inc.
6.4 Data Addressing Modes
While the program memory can be addressed in only
one way, through the Program Counter, information in
the data memory space can be addressed in several
ways. For most instructions, the addressing mode is
fixed. Other instructions may use up to three modes,
depending on which operands are used and whether or
not the extended instruction set is enabled.
The addressing modes are:
• Inherent
• Literal
•Direct
•Indirect
An additional addressing mode, Indexed Literal Offset,
is available when the extended instruction set is
enabled (XINST Configuration bit = 1). For details on
this mode’s operation, see Section 6.6.1 “Indexed
Addressing with Literal Offset”.
6.4.1 INHERENT AND LITERAL
ADDRESSING
Many PIC18 control instructions do not need any
argument at all. They either perform an operation that
globally affects the device or they operate implicitly on
one register. This addressing mode is known as Inherent
Addressing. Examples of this mode include SLEEP,
RESET and DAW.
Other instructions work in a similar way, but require an
additional explicit argument in the opcode. This method
is known as the Literal Addressing mode because the
instructions require some literal value as an argument.
Examples of this include ADDLW and MOVLW which,
respectively, add or move a literal value to the W
register. Other examples include CALL and GOTO,
which include a 20-bit program memory address.
6.4.2 DIRECT ADDRESSING
Direct Addressing specifies all or part of the source
and/or destination address of the operation within the
opcode itself. The options are specified by the
arguments accompanying the instruction.
In the core PIC18 instruction set, bit-oriented and
byte-oriented instructions use some version of Direct
Addressing by default. All of these instructions include
some 8-bit literal address as their Least Significant
Byte. This address specifies the instruction’s data
source as either a register address in one of the banks
of data RAM (see Section 6.3.3 “General Purpose
Register File”) or a location in the Access Bank (see
Section 6.3.2 “Access Bank”).
The Access RAM bit, ‘a’, determines how the address
is interpreted. When ‘a’ is ‘1’, the contents of the BSR
(Section 6.3.1 “Bank Select Register”) are used with
the address to determine the complete 12-bit address
of the register. When ‘a’ is ‘0’, the address is interpreted
as being a register in the Access Bank. Addressing that
uses the Access RAM is sometimes also known as
Direct Forced Addressing mode.
A few instructions, such as MOVFF, include the entire
12-bit address (either source or destination) in their
opcodes. In these cases, the BSR is ignored entirely.
The destination of the operation’s results is determined
by the destination bit, ‘d’. When ‘d’ is ‘1’, the results are
stored back in the source register, overwriting its origi-
nal contents. When ‘d’ is ‘0’, the results are stored in
the W register. Instructions without the ‘d’ argument
have a destination that is implicit in the instruction,
either the target register being operated on or the W
register.
6.4.3 INDIRECT ADDRESSING
Indirect Addressing allows the user to access a location
in data memory without giving a fixed address in the
instruction. This is done by using File Select Registers
(FSRs) as pointers to the locations to be read or written
to. Since the FSRs are themselves located in RAM as
Special Function Registers, they can also be directly
manipulated under program control. This makes FSRs
very useful in implementing data structures such as
tables and arrays in data memory.
The registers for Indirect Addressing are also
implemented with Indirect File Operands (INDFs) that
permit automatic manipulation of the pointer value with
auto-incrementing, auto-decrementing or offsetting
with another value. This allows for efficient code using
loops, such as the example of clearing an entire RAM
bank in Example 6-5. It also enables users to perform
Indexed Addressing and other Stack Pointer
operations for program memory in data memory.
EXAMPLE 6-5: HOW TO CLEAR RAM
(BANK 1) USING
INDIRECT ADDRESSING
Note: The execution of some instructions in the
core PIC18 instruction set are changed
when the PIC18 extended instruction set is
enabled. For more information, see
Section 6.6 “Data Memory and the
Extended Instruction Set”.
LFSR FSR0, 100h ;
NEXT CLRF POSTINC0 ; Clear INDF
; register then
; inc pointer
BTFSS FSR0H, 1 ; All done with
; Bank1?
BRA NEXT ; NO, clear next
CONTINUE ; YES, continue
2012 Microchip Technology Inc. DS30575A-page 137
PIC18F97J94 FAMILY
6.4.3.1 FSR Registers and the
INDF Operand
At the core of Indirect Addressing are three sets of
registers: FSR0, FSR1 and FSR2. Each represents a
pair of 8-bit registers: FSRnH and FSRnL. The four
upper bits of the FSRnH register are not used, so each
FSR pair holds a 12-bit value. This represents a value
that can address the entire range of the data memory
in a linear fashion. The FSR register pairs, then, serve
as pointers to data memory locations.
Indirect Addressing is accomplished with a set of Indi-
rect File Operands, INDF0 through INDF2. These can
be thought of as “virtual” registers. The operands are
mapped in the SFR space, but are not physically imple-
mented. Reading or writing to a particular INDF register
actually accesses its corresponding FSR register pair.
A read from INDF1, for example, reads the data at the
address indicated by FSR1H:FSR1L.
Instructions that use the INDF registers as operands
actually use the contents of their corresponding FSR as
a pointer to the instruction’s target. The INDF operand
is just a convenient way of using the pointer.
Because Indirect Addressing uses a full 12-bit address,
data RAM banking is not necessary. Thus, the current
contents of the BSR and the Access RAM bit have no
effect on determining the target address.
FIGURE 6-8: INDIRECT ADDRESSING
FSR1H:FSR1L
0
7
Data Memory
000h
100h
200h
300h
F00h
E00h
FFFh
Bank 0
Bank 1
Bank 2
Bank 14
Bank 15
Bank 3
through
Bank 13
ADDWF, INDF1, 1
07
Using an instruction with one of the
Indirect Addressing registers as the
operand....
...uses the 12-bit address stored in
the FSR pair associated with that
register....
...to determine the data memory
location to be used in that operation.
In this case, the FSR1 pair contains
FCCh. This means the contents of
location FCCh will be added to that
of the W register and stored back in
FCCh.
xxxx1111 11001100
PIC18F97J94 FAMILY
DS30575A-page 138 2012 Microchip Technology Inc.
6.4.3.2 FSR Registers and POSTINC,
POSTDEC, PREINC and PLUSW
In addition to the INDF operand, each FSR register pair
also has four additional indirect operands. Like INDF,
these are “virtual” registers that cannot be indirectly
read or written to. Accessing these registers actually
accesses the associated FSR register pair, but also
performs a specific action on its stored value.
These operands are:
• POSTDEC – Accesses the FSR value, then
automatically decrements it by ‘1’ afterwards
• POSTINC – Accesses the FSR value, then
automatically increments it by ‘1’ afterwards
• PREINC – Increments the FSR value by ‘1’, then
uses it in the operation
• PLUSW – Adds the signed value of the W register
(range of -127 to 128) to that of the FSR and uses
the new value in the operation
In this context, accessing an INDF register uses the
value in the FSR registers without changing them.
Similarly, accessing a PLUSW register gives the FSR
value, offset by the value in the W register, with neither
value actually changed in the operation. Accessing the
other virtual registers changes the value of the FSR
registers.
Operations on the FSRs with POSTDEC, POSTINC
and PREINC affect the entire register pair. Rollovers of
the FSRnL register, from FFh to 00h, carry over to the
FSRnH register. On the other hand, results of these
operations do not change the value of any flags in the
STATUS register (for example, Z, N and OV bits).
The PLUSW register can be used to implement a form
of Indexed Addressing in the data memory space. By
manipulating the value in the W register, users can
reach addresses that are fixed offsets from pointer
addresses. In some applications, this can be used to
implement some powerful program control structure,
such as software stacks, inside of data memory.
6.4.3.3 Operations by FSRs on FSRs
Indirect Addressing operations that target other FSRs
or virtual registers represent special cases. For
example, using an FSR to point to one of the virtual
registers will not result in successful operations.
As a specific case, assume that the FSR0H:FSR0L
registers contain FE7h, the address of INDF1.
Attempts to read the value of the INDF1, using INDF0
as an operand, will return 00h. Attempts to write to
INDF1, using INDF0 as the operand, will result in a
NOP.
On the other hand, using the virtual registers to write to
an FSR pair may not occur as planned. In these cases,
the value will be written to the FSR pair, but without any
incrementing or decrementing. Thus, writing to INDF2
or POSTDEC2 will write the same value to the
FSR2H:FSR2L.
Since the FSRs are physical registers mapped in the
SFR space, they can be manipulated through all direct
operations. Users should proceed cautiously when
working on these registers, however, particularly if their
code uses Indirect Addressing.
Similarly, operations by Indirect Addressing are gener-
ally permitted on all other SFRs. Users should exercise
the appropriate caution, so that they do not inadvertently
change settings that might affect the operation of the
device.
6.5 Program Memory and the
Extended Instruction Set
The operation of program memory is unaffected by the
use of the extended instruction set.
Enabling the extended instruction set adds five
additional two-word commands to the existing PIC18
instruction set: ADDFSR, CALLW, MOVSF, MOVSS and
SUBFSR. These instructions are executed as described
in Section 6.2.4 “Two-Word Instructions”.
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6.6 Data Memory and the Extended
Instruction Set
Enabling the PIC18 extended instruction set (XINST
Configuration bit = 1) significantly changes certain
aspects of data memory and its addressing. Using the
Access Bank for many of the core PIC18 instructions
introduces a new addressing mode for the data memory
space. This mode also alters the behavior of Indirect
Addressing using FSR2 and its associated operands.
What does not change is just as important. The size of
the data memory space is unchanged, as well as its
linear addressing. The SFR map remains the same.
Core PIC18 instructions can still operate in both Direct
and Indirect Addressing mode. Inherent and literal
instructions do not change at all. Indirect Addressing
with FSR0 and FSR1 also remains unchanged.
6.6.1 INDEXED ADDRESSING WITH
LITERAL OFFSET
Enabling the PIC18 extended instruction set changes
the behavior of Indirect Addressing using the FSR2
register pair and its associated file operands. Under the
proper conditions, instructions that use the Access
Bank – that is, most bit-oriented and byte-oriented
instructions – can invoke a form of Indexed Addressing
using an offset specified in the instruction. This special
addressing mode is known as Indexed Addressing with
Literal Offset or the Indexed Literal Offset mode.
When using the extended instruction set, this
addressing mode requires the following:
• Use of the Access Bank (‘a’ = 0)
• A file address argument that is less than or equal
to 5Fh
Under these conditions, the file address of the
instruction is not interpreted as the lower byte of an
address (used with the BSR in Direct Addressing) or as
an 8-bit address in the Access Bank. Instead, the value
is interpreted as an offset value to an Address Pointer
specified by FSR2. The offset and the contents of FSR2
are added to obtain the target address of the operation.
6.6.2 INSTRUCTIONS AFFECTED BY
INDEXED LITERAL OFFSET MODE
Any of the core PIC18 instructions that can use Direct
Addressing are potentially affected by the Indexed
Literal Offset Addressing mode. This includes all
byte-oriented and bit-oriented instructions, or almost
one-half of the standard PIC18 instruction set. Instruc-
tions that only use Inherent or Literal Addressing
modes are unaffected.
Additionally, byte-oriented and bit-oriented instructions
are not affected if they do not use the Access Bank
(Access RAM bit = 1), or include a file address of 60h
or above. Instructions meeting these criteria will
continue to execute as before. A comparison of the
different possible addressing modes when the
extended instruction set is enabled is shown in
Figure 6-9.
Those who desire to use byte-oriented or bit-oriented
instructions in the Indexed Literal Offset mode should
note the changes to assembler syntax for this mode.
This is described in more detail in Section 29.2.1
“Extended Instruction Syntax”.
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FIGURE 6-9: COMPARING ADDRESSING OPTIONS FOR BIT-ORIENTED AND
BYTE-ORIENTED INSTRUCTIONS (EXTENDED INSTRUCTION SET ENABLED)
EXAMPLE INSTRUCTION: ADDWF, f, d, a (Opcode: 0010 01da ffff ffff)
When a = 0 and f 60h:
The instruction executes in
Direct Forced mode. ‘f’ is
interpreted as a location in the
Access RAM between 060h
and FFFh. This is the same as
locations, F60h to FFFh
(Bank 15), of data memory.
Locations below 060h are not
available in this addressing
mode.
When a = 0 and f5Fh:
The instruction executes in
Indexed Literal Offset mode. ‘f’
is interpreted as an offset to the
address value in FSR2. The
two are added together to
obtain the address of the target
register for the instruction. The
address can be anywhere in
the data memory space.
Note that in this mode, the
correct syntax is now:
ADDWF [k], d
where ‘k’ is the same as ‘f’.
When a = 1 (all values of f):
The instruction executes in
Direct mode (also known as
Direct Long mode). ‘f’ is
interpreted as a location in
one of the 16 banks of the data
memory space. The bank is
designated by the Bank Select
Register (BSR). The address
can be in any implemented
bank in the data memory
space.
000h
060h
100h
F00h
F40h
FFFh
Valid range
00h
60h
FFh
Data Memory
Access RAM
Bank 0
Bank 1
through
Bank 14
Bank 15
SFRs
000h
060h
100h
F00h
F40h
FFFh
Data Memory
Bank 0
Bank 1
through
Bank 14
Bank 15
SFRs
FSR2H FSR2L
ffffffff001001da
ffffffff001001da
000h
060h
100h
F00h
F40h
FFFh
Data Memory
Bank 0
Bank 1
through
Bank 14
Bank 15
SFRs
for ‘f’
BSR
00000000
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6.6.3 MAPPING THE ACCESS BANK IN
INDEXED LITERAL OFFSET MODE
The use of Indexed Literal Offset Addressing mode
effectively changes how the lower part of Access RAM
(00h to 5Fh) is mapped. Rather than containing just the
contents of the bottom part of Bank 0, this mode maps
the contents from Bank 0 and a user-defined “window”
that can be located anywhere in the data memory
space.
The value of FSR2 establishes the lower boundary of
the addresses mapped into the window, while the
upper boundary is defined by FSR2 plus 95 (5Fh).
Addresses in the Access RAM above 5Fh are mapped
as previously described. (See Section 6.3.2 “Access
Bank”.) An example of Access Bank remapping in this
addressing mode is shown in Figure 6-10.
Remapping the Access Bank applies only to operations
using the Indexed Literal Offset mode. Operations that
use the BSR (Access RAM bit = 1) will continue to use
Direct Addressing as before. Any Indirect or Indexed
Addressing operation that explicitly uses any of the
indirect file operands (including FSR2) will continue to
operate as standard Indirect Addressing. Any instruc-
tion that uses the Access Bank, but includes a register
address of greater than 05Fh, will use Direct
Addressing and the normal Access Bank map.
6.6.4 BSR IN INDEXED LITERAL
OFFSET MODE
Although the Access Bank is remapped when the
extended instruction set is enabled, the operation of the
BSR remains unchanged. Direct Addressing, using the
BSR to select the data memory bank, operates in the
same manner as previously described.
FIGURE 6-10: REMAPPING THE ACCESS BANK WITH INDEXED LITERAL
OFFSET ADDRESSING
Data Memory
000h
100h
200h
F60h
F00h
FFFh
Bank 1
Bank 15
Bank 2
through
Bank 14
SFRs
05Fh
ADDWF f, d, a
FSR2H:FSR2L = 120h
Locations in the region
from the FSR2 Pointer
(120h) to the pointer plus
05Fh (17Fh) are mapped
to the bottom of the
Access RAM (000h-05Fh).
Special Function Registers
at F60h through FFFh are
mapped to 60h through
FFh, as usual.
Bank 0 addresses below
5Fh are not available in
this mode. They can still
be addressed by using the
BSR.
Access Bank
00h
FFh
Bank 0
SFRs
Bank 1 “Window”
Not Accessible
Window
Example Situation:
120h
17Fh
5Fh
60h
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NOTES:
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7.0 FLASH PROGRAM MEMORY
The Flash program memory is readable, writable and
erasable during normal operation over the entire VDD
range.
A read from program memory is executed on 1 byte at
a time. A write to program memory is executed on
blocks of 64 bytes at a time or 2 bytes at a time.
Program memory is erased in blocks of 512 bytes at a
time. A bulk erase operation may not be issued from
user code.
Writing or erasing program memory will cease
instruction fetches until the operation is complete. The
program memory cannot be accessed during the write
or erase, therefore, code cannot execute. An internal
programming timer terminates program memory writes
and erases.
A value written to program memory does not need to be
a valid instruction. Executing a program memory
location that forms an invalid instruction results in a
NOP.
7.1 Table Reads and Table Writes
In order to read and write program memory, there are
two operations that allow the processor to move bytes
between the program memory space and the data RAM:
• Table Read (TBLRD)
• Table Write (TBLWT)
The program memory space is 16 bits wide, while the
data RAM space is 8 bits wide. Table reads and table
writes move data between these two memory spaces
through an 8-bit register (TABLAT).
Table read operations retrieve data from program
memory and place it into the data RAM space.
Figure 7-1 shows the operation of a table read with
program memory and data RAM.
Table write operations store data from the data memory
space into holding registers in program memory. The
procedure to write the contents of the holding registers
into program memory is detailed in Section 7.5 “Writing
to Flash Program Memory”. Figure 7-2 shows the
operation of a table write with program memory and data
RAM.
Table operations work with byte entities. A table block
containing data, rather than program instructions, is not
required to be word-aligned. Therefore, a table block can
start and end at any byte address. If a table write is being
used to write executable code into program memory,
program instructions will need to be word-aligned.
FIGURE 7-1: TABLE READ OPERATION
Table Pointer(1)
Table Latch (8-bit)
Program Memory
TBLPTRH TBLPTRL
TABLAT
TBLPTRU
Instruction: TBLRD*
Note 1: Table Pointer register points to a byte in program memory.
Program Memory
(TBLPTR)
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FIGURE 7-2: TABLE WRITE OPERATION
7.2 Control Registers
Several control registers are used in conjunction with
the TBLRD and TBLWT instructions. These include:
• EECON1 register
• EECON2 register
• TABLAT register
• TBLPTR registers
7.2.1 EECON1 AND EECON2 REGISTERS
The EECON1 register (Register 7-1) is the control
register for memory accesses. The EECON2 register is
not a physical register; it is used exclusively in the
memory write and erase sequences. Reading
EECON2 will read all ‘0’s.
The WWPROG bit, when set, will allow programming
two bytes per word on the execution of the WR
command. If this bit is cleared, the WR command will
result in programming on a block of 64 bytes.
The FREE bit, when set, will allow a program memory
erase operation. When FREE is set, the erase
operation is initiated on the next WR command. When
FREE is clear, only writes are enabled.
The WREN bit, when set, will allow a write operation.
On power-up, the WREN bit is clear. The WRERR bit is
set in hardware when the WR bit is set, and cleared
when the internal programming timer expires and the
write operation is complete.
Table Pointer(1) Table Latch (8-bit)
TBLPTRH TBLPTRL TABLAT
Program Memory
(TBLPTR)
TBLPTRU
Instruction: TBLWT*
Note 1: The Table Pointer actually points to one of 64 holding registers; the address of which is determined by
TBLPTRL<5:0>. The process for physically writing data to the program memory array is discussed in
Section 7.5 “Writing to Flash Program Memory”.
Holding Registers
Program Memory
Note: During normal operation, the WRERR is
read as ‘1’. This can indicate that a write
operation was prematurely terminated by
a Reset or a write operation was
attempted improperly.
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Register 7-1: EECON1: EEPROM CONTROL REGISTER 1 (ACCESS FA6h)
U-0 U-0 R/W-0 R/W-0 R/W-x R/W-0 R/S-0 U-0
—— WWPROG FREE WRERR(1)WREN WR —
bit 7 bit 0
Legend: S = Settable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 Unimplemented: Read as ‘0’
bit 5 WWPROG: One Word-Wide Program bit
1 = Programs 2 bytes on the next WR command
0 = Programs 64 bytes on the next WR command
bit 4 FREE: Flash Erase Enable bit
1 = Performs an erase operation on the next WR command (cleared by hardware after completion
of erase)
0 = Performs write-only
bit 3 WRERR: Flash Program Error Flag bit(1)
1 = A write operation is prematurely terminated (any Reset during self-timed programming in normal
operation or an improper write attempt)
0 = The write operation completed
bit 2 WREN: Flash Program Write Enable bit
1 = Allows write cycles to Flash program memory
0 = Inhibits write cycles to Flash program memory
bit 1 WR: Write Control bit
1 = Initiates a program memory erase cycle or write cycle (the operation is self-timed and the bit is
cleared by hardware once the write is complete)
The WR bit can only be set (not cleared) in software.
0 = Write cycle is complete
bit 0 Unimplemented: Read as ‘0’
Note 1: When a WRERR error occurs, the EEPGD and CFGS bits are not cleared. This allows tracing of the error
condition.
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7.2.2 TABLE LATCH REGISTER (TABLAT)
The Table Latch (TABLAT) is an 8-bit register mapped
into the Special Function Register (SFR) space. The
Table Latch register is used to hold 8-bit data during
data transfers between program memory and data
RAM.
7.2.3 TABLE POINTER REGISTER
(TBLPTR)
The Table Pointer (TBLPTR) register addresses a byte
within the program memory. The TBLPTR is comprised
of three SFR registers: Table Pointer Upper Byte, Table
Pointer High Byte and Table Pointer Low Byte
(TBLPTRU:TBLPTRH:TBLPTRL). These three regis-
ters join to form a 22-bit wide pointer. The low-order
21 bits allow the device to address up to 2 Mbytes of
program memory space. The 22nd bit allows access to
the Device ID, the User ID and the Configuration bits.
The Table Pointer register, TBLPTR, is used by the
TBLRD and TBLWT instructions. These instructions can
update the TBLPTR in one of four ways, based on the
table operation. These operations are shown in
Table 7-1 and only affect the low-order 21 bits.
7.2.4 TABLE POINTER BOUNDARIES
TBLPTR is used in reads, writes and erases of the
Flash program memory.
When a TBLRD is executed, all 22 bits of the TBLPTR
determine which byte is read from program memory
into TABLAT.
When a TBLWT is executed, the seven Least Significant
bits (LSbs) of the Table Pointer register
(TBLPTR<6:0>) determine which of the 64 program
memory holding registers is written to. When the timed
write to program memory begins (via the WR bit), the
12 Most Significant bits (MSbs) of the TBLPTR
(TBLPTR<21:10>) determine which program memory
block of 1024 bytes is written to. For more detail, see
Section 7.5 “Writing to Flash Program Memory”.
When an erase of program memory is executed, the
12 MSbs of the Table Pointer register point to the
1024-byte block that will be erased. The LSbs are
ignored.
Figure 7-3 describes the relevant boundaries of the
TBLPTR based on Flash program memory operations.
TABLE 7-1: TABLE POINTER OPERATIONS WITH TBLRD AND TBLWT INSTRUCTIONS
FIGURE 7-3: TABLE POINTER BOUNDARIES BASED ON OPERATION
Example Operation on Table Pointer
TBLRD*
TBLWT* TBLPTR is not modified
TBLRD*+
TBLWT*+ TBLPTR is incremented after the read/write
TBLRD*-
TBLWT*- TBLPTR is decremented after the read/write
TBLRD+*
TBLWT+* TBLPTR is incremented before the read/write
21 16 15 87 0
TABLE READ – TBLPTR<21:0>
TBLPTRL
TBLPTRH
TBLPTRU
ERASE: TBLPTR<20:10>
TABLE WRITE: TBLPTR<20:6>
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7.3 Reading the Flash Program
Memory
The TBLRD instruction is used to retrieve data from
program memory and places it into data RAM. Table
reads from program memory are performed one byte at
a time.
The TBLPTR points to a byte address in program
space. Executing TBLRD places the byte pointed to into
TABLAT. In addition, the TBLPTR can be modified
automatically for the next table read operation.
The internal program memory is typically organized by
words. The Least Significant bit of the address selects
between the high and low bytes of the word.
Figure 7-4 shows the interface between the internal
program memory and the TABLAT.
FIGURE 7-4: READS FROM FLASH PROGRAM MEMORY
EXAMPLE 7-1: READING A FLASH PROGRAM MEMORY WORD
(Even Byte Address)
Program Memory
(Odd Byte Address)
TBLRD
TBLPTR = xxxxx1
FETCH
Instruction Register
(IR)
TBLPTR = xxxxx0
TABLAT
Read Register
MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base
MOVWF TBLPTRU ; address of the word
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
READ_WORD
TBLRD*+ ; read into TABLAT and increment
MOVF TABLAT, W ; get data
MOVWF WORD_EVEN
TBLRD*+ ; read into TABLAT and increment
MOVF TABLAT, W ; get data
MOVWF WORD_ODD
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7.4 Erasing Flash Program Memory
The minimum erase block is 256 words or 512 bytes.
Only through the use of an external programmer, or
through ICSP control, can larger blocks of program
memory be bulk erased. Word erase in the Flash array
is not supported.
When initiating an erase sequence from the microcon-
troller itself, a block of 512 bytes of program memory is
erased. The Most Significant 12 bits of the
TBLPTR<21:10> point to the block being erased;
TBLPTR<9:0> are ignored.
The EECON1 register commands the erase operation.
The WREN bit must be set to enable write operations.
The FREE bit is set to select an erase operation. For
protection, the write initiate sequence for EECON2
must be used.
A long write is necessary for erasing the internal Flash.
Instruction execution is halted while in a long write
cycle. The long write will be terminated by the internal
programming timer.
7.4.1 FLASH PROGRAM MEMORY
ERASE SEQUENCE
The sequence of events for erasing a block of internal
program memory location is:
1. Load Table Pointer register with address of row
being erased.
2. Set the WREN and FREE bits (EECON1<2,4>)
to enable the erase operation.
3. Disable interrupts.
4. Write 55h to EECON2.
5. Write 0AAh to EECON2.
6. Set the WR bit; this will begin the erase cycle.
7. The CPU will stall for the duration of the erase
for TIE (see Parameter D133B).
8. Re-enable interrupts.
EXAMPLE 7-2: ERASING A FLASH PROGRAM MEMORY ROW
MOVLW CODE_ADDR_UPPER ; load TBLPTR with the base
MOVWF TBLPTRU ; address of the memory block
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
ERASE_ROW
BSF EECON1, WREN ; enable write to memory
BSF EECON1, FREE ; enable Row Erase operation
BCF INTCON, GIE ; disable interrupts
Required MOVLW 0x55
Sequence MOVWF EECON2 ; write 55h
MOVLW 0xAA
MOVWF EECON2 ; write 0AAh
BSF EECON1, WR ; start erase (CPU stall)
BSF INTCON, GIE ; re-enable interrupts
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7.5 Writing to Flash Program Memory
The programming block is 32 words or 64 bytes.
Programming one word or 2 bytes at a time is also sup-
ported.
Table writes are used internally to load the holding
registers needed to program the Flash memory. There
are 64 holding registers used by the table writes for
programming.
Since the Table Latch (TABLAT) is only a single byte, the
TBLWT instruction may need to be executed 64 times for
each programming operation (if WWPROG = 0). All of
the table write operations will essentially be short writes
because only the holding registers are written. At the
end of updating the 64 holding registers, the EECON1
register must be written to in order to start the
programming operation with a long write.
The long write is necessary for programming the internal
Flash. Instruction execution is halted while in a long write
cycle. The long write will be terminated by the internal
programming timer.
The on-chip timer controls the write time. The write/
erase voltages are generated by an on-chip charge
pump, rated to operate over the voltage range of the
device.
FIGURE 7-5: TABLE WRITES TO FLASH PROGRAM MEMORY
7.5.1 FLASH PROGRAM MEMORY WRITE
SEQUENCE
The sequence of events for programming an internal
program memory location should be:
1. Read the 512 bytes into RAM.
2. Update the data values in RAM as necessary.
3. Load the Table Pointer register with the address
being erased.
4. Execute the erase procedure.
5. Load the Table Pointer register with the address
of the first byte being written, minus 1.
6. Write the 64 bytes into the holding registers with
auto-pre-increment.
7. Set the WREN bit (EECON1<2>) to enable byte
writes.
8. Disable the interrupts.
9. Write 55h to EECON2.
10. Write 0xAAh to EECON2.
11. Set the WR bit. This will begin the write cycle.
The CPU will stall for duration of the write for TIW
(see Parameter D133A).
12. Re-enable the interrupts.
13. Verify the memory (table read).
An example of the required code is shown in
Example 7-3 on the following Page 150.
Note 1: Unlike previous PIC® MCUs, devices of
the PIC18F97J94 family do not reset the
holding registers after a write occurs. The
holding registers must be cleared or
overwritten before a programming
sequence.
2: To maintain the endurance of the
program memory cells, each Flash byte
should not be programmed more than
once between erase operations. Before
attempting to modify the contents of the
target cell a second time, an erase of the
target page, or a bulk erase of the entire
memory, must be performed.
TABLAT
TBLPTR = xxxx3FTBLPTR = xxxxx1TBLPTR = xxxxx0
Write Register
TBLPTR = xxxxx2
Program Memory
Holding Register Holding Register Holding Register Holding Register
88 8 8
Note: Before setting the WR bit, the Table
Pointer address needs to be within the
intended address range of the 64 bytes in
the holding register.
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EXAMPLE 7-3: WRITING TO FLASH PROGRAM MEMORY
MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base
MOVWF TBLPTRU ; address of the memory block, minus 1
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW
MOVWF TBLPTRL
ERASE_BLOCK
BSF EECON1, WREN ; enable write to memory
BSF EECON1, FREE ; enable Erase operation
BCF INTCON, GIE ; disable interrupts
MOVLW 55h
MOVWF EECON2 ; write 55h
MOVLW 0AAh
MOVWF EECON2 ; write 0AAh
BSF EECON1, WR ; start erase (CPU stall)
BSF INTCON, GIE ; re-enable interrupts
MOVLW D’8’
MOVWF WRITE_COUNTER ; Need to write 8 blocks of 64 to write
; one erase block of 512
RESTART BUFFER
MOVLW D'64'
MOVWF COUNTER
MOVLW BUFFER_ADDR_HIGH ; point to buffer
MOVWF FSR0H
MOVLW BUFFER_ADDR_LOW
MOVWF FSR0L
FILL_BUFFER
... ; read the new data from I2C, SPI,
; PSP, USART, etc.
WRITE_BUFFER
MOVLW D’64 ; number of bytes in holding register
MOVWF COUNTER
WRITE_BYTE_TO_HREGS
MOVFF POSTINC0, WREG ; get low byte of buffer data
MOVWF TABLAT ; present data to table latch
TBLWT+* ; write data, perform a short write
; to internal TBLWT holding register.
DECFSZ COUNTER ; loop until buffers are full
BRA WRITE_BYTE_TO_HREGS
PROGRAM_MEMORY
BSF EECON1, WREN ; enable write to memory
BCF INTCON, GIE ; disable interrupts
MOVLW 55h
Required MOVWF EECON2 ; write 55h
Sequence MOVLW 0AAh
MOVWF EECON2 ; write 0AAh
BSF EECON1, WR ; start program (CPU stall)
BSF INTCON, GIE ; re-enable interrupts
BCF EECON1, WREN ; disable write to memory
DECFSZ WRITE_COUNTER ; done with one write cycle
BRA RESTART_BUFFER ; if not done replacing the erase block
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7.5.2 FLASH PROGRAM MEMORY WRITE
SEQUENCE (WORD PROGRAMMING)
The PIC18F97J94 family of devices has a feature that
allows programming a single word (two bytes). This
feature is enabled when the WWPROG bit is set. If the
memory location is already erased, the following
sequence is required to enable this feature:
1. Load the Table Pointer register with the address
of the data to be written. (It must be an even
address.)
2. Write the 2 bytes into the holding registers by
performing table writes. (Do not post-increment
on the second table write).
3. Set the WREN bit (EECON1<2>) to enable
writes and the WWPROG bit (EECON1<5>) to
select Word Write mode.
4. Disable interrupts.
5. Write 55h to EECON2.
6. Write 0AAh to EECON2.
7. Set the WR bit; this will begin the write cycle.
8. The CPU will stall for the duration of the write for
TIW (see Parameter D133A).
9. Re-enable interrupts.
EXAMPLE 7-4: SINGLE-WORD WRITE TO FLASH PROGRAM MEMORY
MOVLW CODE_ADDR_UPPER ; Load TBLPTR with the base address
MOVWF TBLPTRU
MOVLW CODE_ADDR_HIGH
MOVWF TBLPTRH
MOVLW CODE_ADDR_LOW ; The table pointer must be loaded with an even address
MOVWF TBLPTRL
MOVLW DATA0 ; LSB of word to be written
MOVWF TABLAT
TBLWT*+
MOVLW DATA1 ; MSB of word to be written
MOVWF TABLAT
TBLWT* ; The last table write must not increment the
table pointer! The table pointer needs to
point to the MSB before starting the write operation.
PROGRAM_MEMORY
BSF EECON1, WWPROG ; enable single word write
BSF EECON1, WREN ; enable write to memory
BCF INTCON, GIE ; disable interrupts
MOVLW 55h
Required MOVWF EECON2 ; write 55h
Sequence MOVLW 0AAh
MOVWF EECON2 ; write AAh
BSF EECON1, WR ; start program (CPU stall)
BSF INTCON, GIE ; re-enable interrupts
BCF EECON1, WWPROG ; disable single word write
BCF EECON1, WREN ; disable write to memory
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DS30575A-page 152 2012 Microchip Technology Inc.
7.5.3 WRITE VERIFY
Depending on the application, good programming
practice may dictate that the value written to the
memory should be verified against the original value.
This should be used in applications where excessive
writes can stress bits near the specification limit.
7.5.4 UNEXPECTED TERMINATION OF
WRITE OPERATION
If a write is terminated by an unplanned event, such as
loss of power or an unexpected Reset, the memory
location just programmed should be verified and repro-
grammed if needed. If the write operation is interrupted
by a MCLR Reset, or a WDT time-out Reset during nor-
mal operation, the user can check the WRERR bit and
rewrite the location(s) as needed
7.6 Flash Program Operation During
Code Protection
See Section 28.4.5 “Program Verification and Code
Protection” for details on code protection of Flash
program memory.
2012 Microchip Technology Inc. DS30575A-page 153
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8.0 EXTERNAL MEMORY BUS
The External Memory Bus (EMB) allows the device to
access external memory devices (such as Flash,
EPROM or SRAM) as program or data memory. It
supports both 8 and 16-Bit Data Width modes, and
three address widths of up to 20 bits.
The bus is implemented with 28 pins, multiplexed
across four I/O ports. Three ports (PORTD, PORTE
and PORTH) are multiplexed with the address/data bus
for a total of 20 available lines, while PORTJ is
multiplexed with the bus control signals.
A list of the pins and their functions is provided in
Table 8-1.
TABLE 8-1: PIC18F97J94 FAMILY EXTERNAL BUS – I/O PORT FUNCTIONS
Note: The External Memory Bus is not
implemented on 64-pin devices.
Name Port Bit External Memory Bus Function
RD0/AD0 PORTD 0 Address Bit 0 or Data Bit 0
RD1/AD1 PORTD 1 Address Bit 1 or Data Bit 1
RD2/AD2 PORTD 2 Address Bit 2 or Data Bit 2
RD3/AD3 PORTD 3 Address Bit 3 or Data Bit 3
RD4/AD4 PORTD 4 Address Bit 4 or Data Bit 4
RD5/AD5 PORTD 5 Address Bit 5 or Data Bit 5
RD6/AD6 PORTD 6 Address Bit 6 or Data Bit 6
RD7/AD7 PORTD 7 Address Bit 7 or Data Bit 7
RE0/AD8 PORTE 0 Address Bit 8 or Data Bit 8
RE1/AD9 PORTE 1 Address Bit 9 or Data Bit 9
RE2/AD10 PORTE 2 Address Bit 10 or Data Bit 10
RE3/AD11 PORTE 3 Address Bit 11 or Data Bit 11
RE4/AD12 PORTE 4 Address Bit 12 or Data Bit 12
RE5/AD13 PORTE 5 Address Bit 13 or Data Bit 13
RE6/AD14 PORTE 6 Address Bit 14 or Data Bit 14
RE7/AD15 PORTE 7 Address Bit 15 or Data Bit 15
RH0/A16 PORTH 0 Address Bit 16
RH1/A17 PORTH 1 Address Bit 17
RH2/A18 PORTH 2 Address Bit 18
RH3/A19 PORTH 3 Address Bit 19
RJ0/ALE PORTJ 0 Address Latch Enable (ALE) Control Pin
RJ1/OE PORTJ 1 Output Enable (OE) Control Pin
RJ2/WRL PORTJ 2 Write Low (WRL) Control Pin
RJ3/WRH PORTJ 3 Write High (WRH) Control Pin
RJ4/BA0 PORTJ 4 Byte Address Bit 0 (BA0)
RJ5/CE PORTJ 5 Chip Enable (CE) Control Pin
RJ6/LB PORTJ 6 Lower Byte Enable (LB) Control Pin
RJ7/UB PORTJ 7 Upper Byte Enable (UB) Control Pin
Note: For the sake of clarity, only I/O port and external bus assignments are shown here. One or more additional
multiplexed features may be available on some pins.
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8.1 External Memory Bus Control
The operation of the interface is controlled by the
MEMCON register (Register 8-1). This register is
available in all program memory operating modes,
except Microcontroller mode. In this mode, the register
is disabled and cannot be written to.
The EBDIS bit (MEMCON<7>) controls the operation
of the bus and related port functions. Clearing EBDIS
enables the interface and disables the I/O functions of
the ports, as well as any other functions multiplexed to
those pins. Setting the bit enables the I/O ports and
other functions, but allows the interface to override
everything else on the pins when an external memory
operation is required. By default, the external bus is
always enabled and disables all other I/O.
The operation of the EBDIS bit is also influenced by the
program memory mode being used. This is discussed
in more detail in Section 8.5 “Program Memory
Modes and the External Memory Bus”.
The WAITx bits allow for the addition of Wait states to
external memory operations. The use of these bits is
discussed in Section 8.3 “Wait States”.
The WMx bits select the particular operating mode
used when the bus is operating in 16-Bit Data Width
mode. This is discussed in more detail in Section 8.6
“16-Bit Data Width Modes”. These bits have no effect
when an 8-Bit Data Width mode is selected.
REGISTER 8-1: MEMCON: EXTERNAL MEMORY BUS CONTROL REGISTER(1)
R/W-0 U-0 R/W-0 R/W-0 U-0 U-0 R/W-0 R/W-0
EBDIS —WAIT1WAIT0——WM1WM0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 EBDIS: External Bus Disable bit
1 = External bus is enabled when microcontroller accesses external memory; otherwise, all external
bus drivers are mapped as I/O ports
0 = External bus is always enabled, I/O ports are disabled
bit 6 Unimplemented: Read as ‘0’
bit 5-4 WAIT<1:0>: Table Reads and Writes Bus Cycle Wait Count bits
11 = Table reads and writes will wait 0 TCY
10 = Table reads and writes will wait 1 TCY
01 = Table reads and writes will wait 2 TCY
00 = Table reads and writes will wait 3 TCY
bit 3-2 Unimplemented: Read as ‘0’
bit 1-0 WM<1:0>: TBLWT Operation with 16-Bit Data Bus Width Select bits
1x = Word Write mode: TABLAT word output, WRH is active when TABLAT is written
01 = Byte Select mode: TABLAT data is copied on both MSB and LSB, WRH and (UB or LB) will activate
00 = Byte Write mode: TABLAT data is copied on both MSB and LSB, WRH or WRL will activate
Note 1: This register is unimplemented on 64-pin devices, read as ‘0’.
2012 Microchip Technology Inc. DS30575A-page 155
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8.2 Address and Data Width
The PIC18F97J94 family of devices can be indepen-
dently configured for different address and data widths
on the same memory bus. Both address and data width
are set by Configuration bits in the CONFIG5L register.
As Configuration bits, this means that these options
can only be configured by programming the device and
are not controllable in software.
The BW bit selects an 8-bit or 16-bit data bus width.
Setting this bit (default) selects a data width of 16 bits.
The ABW<1:0> bits determine both the program mem-
ory operating mode and the address bus width. The
available options are 20-bit, 16-bit and 12-bit, as well
as Microcontroller mode (external bus disabled).
Selecting a 16-bit or 12-bit width makes a correspond-
ing number of high-order lines available for I/O
functions. These pins are no longer affected by the
setting of the EBDIS bit. For example, selecting a
16-Bit Addressing mode (ABW<1:0> = 01) disables
A<19:16> and allows PORTH<3:0> to function without
interruptions from the bus. Using the smaller address
widths allows users to tailor the memory bus to the size
of the external memory space for a particular design
while freeing up pins for dedicated I/O operation.
Because the ABWx bits have the effect of disabling
pins for memory bus operations, it is important to
always select an address width at least equal to the
data width. If a 12-bit address width is used with a
16-bit data width, the upper four bits of data will not be
available on the bus.
All combinations of address and data widths require
multiplexing of address and data information on the
same lines. The address and data multiplexing, as well
as I/O ports made available by the use of smaller
address widths, are summarized in Ta bl e 8 - 2 .
8.2.1 ADDRESS SHIFTING ON THE
EXTERNAL BUS
By default, the address presented on the external bus
is the value of the PC. In practical terms, this means
that addresses in the external memory device, below
the top of on-chip memory, are unavailable to the
microcontroller. To access these physical locations, the
glue logic between the microcontroller and the external
memory must somehow translate addresses.
To simplify the interface, the external bus offers an
extension of Extended Microcontroller mode that
automatically performs address shifting. This feature is
controlled by the EASHFT Configuration bit. Setting
this bit offsets addresses on the bus by the size of the
microcontroller’s on-chip program memory and sets
the bottom address at 0000h. This allows the device to
use the entire range of physical addresses of the
external memory.
8.2.2 21-BIT ADDRESSING
As an extension of 20-bit address width operation, the
External Memory Bus can also fully address a 2-Mbyte
memory space. This is done by using the Bus Address
Bit 0 (BA0) control line as the Least Significant bit of the
address. The UB and LB control signals may also be
used with certain memory devices to select the upper
and lower bytes within a 16-bit wide data word.
This addressing mode is available in both 8-Bit and
certain 16-Bit Data Width modes. Additional details are
provided in Section 8.6.3 “16-Bit Byte Select Mode”
and Section 8.7 “8-Bit Data Width Mode”.
TABLE 8-2: ADDRESS AND DATA LINES FOR DIFFERENT ADDRESS AND DATA WIDTHS
Data Width Address Width
Multiplexed Data and
Address Lines (and
Corresponding Ports)
Address Only Lines
(and Corresponding
Ports)
Ports Available
for I/O
8-bit
12-bit
AD<7:0>
(PORTD<7:0>)
AD<11:8>
(PORTE<3:0>)
PORTE<7:4>,
All of PORTH
16-bit AD<15:8>
(PORTE<7:0>) All of PORTH
20-bit
A<19:16>, AD<15:8>
(PORTH<3:0>,
PORTE<7:0>)
—
16-bit
16-bit AD<15:0>
(PORTD<7:0>,
PORTE<7:0>)
— All of PORTH
20-bit A<19:16>
(PORTH<3:0>) —
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8.3 Wait States
While it may be assumed that external memory devices
will operate at the microcontroller clock rate, this is
often not the case. In fact, many devices require longer
times to write or retrieve data than the time allowed by
the execution of table read or table write operations.
To compensate for this, the External Memory Bus can
be configured to add a fixed delay to each table opera-
tion using the bus. Wait states are enabled by setting
the WAIT Configuration bit. When enabled, the amount
of delay is set by the WAIT<1:0> bits (MEMCON<5:4>).
The delay is based on multiples of microcontroller
instruction cycle time and is added following the
instruction cycle when the table operation is executed.
The range is from no delay to 3 TCY (default value).
8.4 Port Pin Weak Pull-ups
With the exception of the upper address lines,
A<19:16>, the pins associated with the External Mem-
ory Bus are equipped with weak pull-ups. The pull-ups
are controlled by the upper nibble of the PADCFG
register (PADCFG<7:4>). They are named RDPU,
REPU, RHPU and RJPU, and control pull-ups on
PORTD, PORTE, PORTH and PORTJ, respectively.
Setting one of these bits enables the corresponding
pull-ups for that port. All pull-ups are disabled by default
on all device Resets.
In Extended Microcontroller mode, the port pull-ups
can be useful in preserving the memory state on the
external bus while the bus is temporarily disabled
(EBDIS = 1).
8.5 Program Memory Modes and the
External Memory Bus
The PIC18F97J94 family of devices is capable of
operating in one of two program memory modes, using
combinations of on-chip and external program memory.
The functions of the multiplexed port pins depend on
the program memory mode selected, as well as the
setting of the EBDIS bit.
In Microcontroller Mode, the bus is not active and the
pins have their port functions only. Writes to the
MEMCOM register are not permitted. The Reset value
of EBDIS (‘0’) is ignored and the ABWx pins behave as
I/O ports.
In Extended Microcontroller Mode, the external
program memory bus shares I/O port functions on the
pins. When the device is fetching or doing table
read/table write operations on the external program
memory space, the pins will have the external bus
function.
If the device is fetching and accessing internal program
memory locations only, the EBDIS control bit will
change the pins from external memory to I/O port
functions. When EBDIS = 0, the pins function as the
external bus. When EBDIS = 1, the pins function as I/O
ports.
If the device fetches or accesses external memory
while EBDIS = 1, the pins will switch to the external
bus. If the EBDIS bit is set by a program executing from
external memory, the action of setting the bit will be
delayed until the program branches into the internal
memory. At that time, the pins will change from external
bus to I/O ports.
If the device is executing out of internal memory when
EBDIS = 0, the memory bus address/data and control
pins will not be active. They will go to a state where the
active address/data pins are tri-state; the CE, OE,
WRH, WRL, UB and LB signals are ‘1’, and ALE and
BA0 are ‘0’. Note that only those pins associated with
the current address width are forced to tri-state; the
other pins continue to function as I/O. In the case of
16-bit address width, for example, only AD<15:0>
(PORTD and PORTE) are affected; A<19:16>
(PORTH<3:0>) continue to function as I/O.
In all external memory modes, the bus takes priority
over any other peripherals that may share pins with it.
This includes the Parallel Master Port and serial
communication modules which would otherwise take
priority over the I/O port.
8.6 16-Bit Data Width Modes
In 16-Bit Data Width mode, the external memory
interface can be connected to external memories in
three different configurations:
• 16-Bit Byte Write
•16-Bit Word Write
• 16-Bit Byte Select
The configuration to be used is determined by the
WM<1:0> bits in the MEMCON register
(MEMCON<1:0>). These three different configurations
allow the designer maximum flexibility in using both
8-bit and 16-bit devices with 16-bit data.
For all 16-bit modes, the Address Latch Enable (ALE)
pin indicates that the address bits, AD<15:0>, are avail-
able on the external memory interface bus. Following
the address latch, the Output Enable (OE) signal will
enable both bytes of program memory at once to form
a 16-bit instruction word. The Chip Enable (CE signal)
is active at any time that the microcontroller accesses
external memory, whether reading or writing; it is
inactive (asserted high) whenever the device is in
Sleep mode.
In Byte Select mode, JEDEC standard Flash memories
will require BA0 for the byte address line and one I/O
line to select between Byte and Word mode. The other
16-bit modes do not need BA0. JEDEC standard static
RAM memories will use the UB or LB signals for byte
selection.
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8.6.1 16-BIT BYTE WRITE MODE
Figure 8-1 shows an example of 16-Bit Byte Write
mode for PIC18F97J94 family devices. This mode is
used for two separate 8-bit memories connected for
16-bit operation. This generally includes basic EPROM
and Flash devices. It allows table writes to byte-wide
external memories.
During a TBLWT instruction cycle, the TABLAT data is
presented on the upper and lower bytes of the
AD<15:0> bus. The appropriate WRH or WRL control
line is strobed on the LSb of the TBLPTR.
FIGURE 8-1: 16-BIT BYTE WRITE MODE EXAMPLE
AD<7:0>
A<19:16>(1)
ALE
D<15:8>
373 A<x:0>
D<7:0>
A<19:0> A<x:0>
D<7:0>
373
OE
WRH
OE OE
WR(2) WR(2)
CE CE
Note 1: Upper order address lines are used only for 20-bit address widths.
2: This signal only applies to table writes. See Section 7.1 “Table Reads and Table Writes”.
WRL
D<7:0>
(LSB)
(MSB)
D<7:0>
AD<15:8>
Address Bus
Data Bus
Control Lines
CE
PIC18F97J94
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DS30575A-page 158 2012 Microchip Technology Inc.
8.6.2 16-BIT WORD WRITE MODE
Figure 8-2 shows an example of 16-Bit Word Write
mode for PIC18F97J94 family devices. This mode is
used for word-wide memories, which includes some of
the EPROM and Flash-type memories. This mode
allows opcode fetches and table reads from all forms of
16-bit memory, and table writes to any type of
word-wide external memories. This method makes a
distinction between TBLWT cycles to even or odd
addresses.
During a TBLWT cycle to an even address
(TBLPTR<0> = 0), the TABLAT data is transferred to a
holding latch and the external address data bus is
tri-stated for the data portion of the bus cycle. No write
signals are activated.
During a TBLWT cycle to an odd address
(TBLPTR<0> = 1), the TABLAT data is presented on
the upper byte of the AD<15:0> bus. The contents of
the holding latch are presented on the lower byte of the
AD<15:0> bus.
The WRH signal is strobed for each write cycle; the
WRL pin is unused. The signal on the BA0 pin indicates
the LSb of the TBLPTR, but it is left unconnected.
Instead, the UB and LB signals are active to select both
bytes. The obvious limitation to this method is that the
table write must be done in pairs on a specific word
boundary to correctly write a word location.
FIGURE 8-2: 16-BIT WORD WRITE MODE EXAMPLE
AD<7:0>
AD<15:8>
ALE
373 A<20:1>
373
OE
WRH
A<19:16>(1)
A<x:0>
D<15:0>
OE WR(2)
CE
D<15:0>
JEDEC Word
EPROM Memory
Address Bus
Data Bus
Control Lines
Note 1: Upper order address lines are used only for 20-bit address widths.
2: This signal only applies to table writes. See Section 7.1 “Table Reads and Table Writes”.
CE
PIC18F97J94
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8.6.3 16-BIT BYTE SELECT MODE
Figure 8-3 shows an example of 16-Bit Byte Select
mode. This mode allows table write operations to
word-wide external memories with byte selection
capability. This generally includes both word-wide
Flash and SRAM devices.
During a TBLWT cycle, the TABLAT data is presented
on the upper and lower byte of the AD<15:0> bus. The
WRH signal is strobed for each write cycle; the WRL
pin is not used. The BA0 or UB/LB signals are used to
select the byte to be written, based on the Least
Significant bit of the TBLPTR register.
Flash and SRAM devices use different control signal
combinations to implement Byte Select mode. JEDEC
standard Flash memories require that a controller I/O
port pin be connected to the memory’s BYTE/WORD
pin to provide the select signal. They also use the BA0
signal from the controller as a byte address. JEDEC
standard static RAM memories, on the other hand, use
the UB or LB signals to select the byte.
FIGURE 8-3: 16-BIT BYTE SELECT MODE EXAMPLE
AD<7:0>
AD<15:8>
ALE
373
A<20:1>
373
OE
WRH
A<19:16>(2)
WRL
BA0
JEDEC Word
A<x:1>
D<15:0>
A<20:1>
CE
D<15:0>
I/O
OE WR(1)
A0
BYTE/WORD
FLASH Memory
JEDEC Word
A<x:1>
D<15:0>
CE
D<15:0>
OE WR(1)
LB
UB
SRAM Memory
LB
UB
138(3)
Address Bus
Data Bus
Control Lines
Note 1: This signal only applies to table writes. See Section 7.1 “Table Reads and Table Writes”.
2: Upper order address lines are used only for 20-bit address width.
3: Demultiplexing is only required when multiple memory devices are accessed.
PIC18F97J94
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8.6.4 16-BIT MODE TIMING
The presentation of control signals on the External
Memory Bus is different for the various operating
modes. Typical signal timing diagrams are shown in
Figure 8-4 and Figure 8-5.
FIGURE 8-4: EXTERNAL MEMORY BUS TIMING FOR TBLRD
(EXTENDED MICROCONTROLLER MODE)
FIGURE 8-5: EXTERNAL MEMORY BUS TIMING FOR SLEEP
(EXTENDED MICROCONTROLLER MODE)
Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4
A<19:16>
ALE
OE
AD<15:0>
CE
Opcode Fetch Opcode Fetch Opcode Fetch
TBLRD *
TBLRD Cycle 1
ADDLW 55h
from 000100h
Q2Q1 Q3 Q4
0Ch
CF33h
TBLRD 92h
from 199E67h
9256h
from 000104h
Memory
Cycle
Instruction
Execution INST(PC – 2) TBLRD Cycle 2
MOVLW 55h
from 000102h
MOVLW
Q2Q1 Q3 Q4 Q2Q1 Q3 Q4
A<19:16>
ALE
OE
3AAAh
AD<15:0>
00h 00h
CE
Opcode Fetch Opcode Fetch
SLEEP
SLEEP
from 007554h
Q1
Bus Inactive
0003h
3AABh
0E55h
Memory
Cycle
Instruction
Execution INST(PC – 2)
Sleep Mode,
MOVLW 55h
from 007556h
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8.7 8-Bit Data Width Mode
In 8-Bit Data Width mode, the External Memory Bus
operates only in Multiplexed mode; that is, data shares
the 8 Least Significant bits of the address bus.
Figure 8-6 shows an example of 8-Bit Multiplexed
mode for 100-pin devices. This mode is used for a
single, 8-bit memory, connected for 16-bit operation.
The instructions will be fetched as two 8-bit bytes on a
shared data/address bus. The two bytes are sequen-
tially fetched within one instruction cycle (TCY).
Therefore, the designer must choose external memory
devices, according to timing calculations based on
1/2 TCY (2 times the instruction rate). For proper mem-
ory speed selection, glue logic propagation delay times
must be considered, along with setup and hold times.
The Address Latch Enable (ALE) pin indicates that the
address bits, AD<15:0>, are available on the External
Memory Bus interface. The Output Enable (OE) signal
will enable one byte of program memory for a portion of
the instruction cycle, then BA0 will change and the
second byte will be enabled to form the 16-bit instruc-
tion word. The Least Significant bit of the address, BA0,
must be connected to the memory devices in this
mode. The Chip Enable (CE) signal is active at any
time that the microcontroller accesses external
memory, whether reading or writing. It is inactive
(asserted high) whenever the device is in Sleep mode.
This generally includes basic EPROM and Flash
devices. It allows table writes to byte-wide external
memories.
During a TBLWT instruction cycle, the TABLAT data is
presented on the upper and lower bytes of the
AD<15:0> bus. The appropriate level of the BA0 control
line is strobed on the LSb of the TBLPTR.
FIGURE 8-6: 8-BIT MULTIPLEXED MODE EXAMPLE
AD<7:0>
A<19:16>(1)
ALE D<15:8>
373 A<19:0> A<x:1>
D<7:0>
OE
OE WR(2)
CE
Note 1: Upper order address bits are only used for 20-bit address width. The upper AD byte is used for all
address widths except 8-bit.
2: This signal only applies to table writes. See Section 7.1 “Table Reads and Table Writes”.
WRL
D<7:0>
AD<15:8>(1)
Address Bus
Data Bus
Control Lines
CE
A0
BA0
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8.7.1 8-BIT MODE TIMING
The presentation of control signals on the External
Memory Bus is different for the various operating
modes. Typical signal timing diagrams are shown in
Figure 8-7 and Figure 8-8.
FIGURE 8-7: EXTERNAL MEMORY BUS TIMING FOR TBLRD
(EXTENDED MICROCONTROLLER MODE)
FIGURE 8-8: EXTERNAL MEMORY BUS TIMING FOR SLEEP
(EXTENDED MICROCONTROLLER MODE)
Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4
A<19:16>
ALE
OE
AD<7:0>
CE
Opcode Fetch Opcode Fetch Opcode Fetch
TBLRD *
TBLRD Cycle 1
ADDLW 55h
from 000100h
Q2Q1 Q3 Q4
0Ch
33h
TBLRD 92h
from 199E67h
92h
from 000104h
Memory
Cycle
Instruction
Execution INST(PC – 2) TBLRD Cycle 2
MOVLW 55h
from 000102h
MOVLW
AD<15:8> CFh
Q2Q1 Q3 Q4 Q2Q1 Q3 Q4
A<19:16>
ALE
OE
AAh
AD<7:0>
00h 00h
CE
Opcode Fetch Opcode Fetch
SLEEP
SLEEP
from 007554h
Q1
Bus Inactive
00h ABh 55h
Memory
Cycle
Instruction
Execution INST(PC – 2)
Sleep Mode,
MOVLW 55h
from 007556h
AD<15:8> 3Ah 3Ah
03h 0Eh
BA0
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8.8 Operation in Power-Managed
Modes
In alternate, power-managed Run modes, the external
bus continues to operate normally. If a clock source
with a lower speed is selected, bus operations will run
at that speed. In these cases, excessive access times
for the external memory may result if Wait states have
been enabled and added to external memory opera-
tions. If operations in a lower power Run mode are
anticipated, users should provide in their applications
for adjusting memory access times at the lower clock
speeds.
In Sleep and Idle modes, the microcontroller core does
not need to access data; bus operations are sus-
pended. The state of the external bus is frozen, with the
address/data pins and most of the control pins holding
at the same state they were in when the mode was
invoked. The only potential changes are to the CE, LB
and UB pins, which are held at logic high.
TABLE 8-3: REGISTERS ASSOCIATED WITH THE EXTERNAL MEMORY BUS
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
MEMCON(1)EBDIS —WAIT1WAIT0——WM1WM0
PADCFG RDPU REPU RFPU RGPU RHPU RJPU RKPU RLPU
PMD4 CMP1MD CMP2MD CMP3MD USBMD IOCMD LVDMD —EMBMD
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used during External Memory Bus access.
Note 1: This register is unimplemented on 64-pin devices read as ‘0’.
PIC18F97J94 FAMILY
DS30575A-page 164 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 165
PIC18F97J94 FAMILY
9.0 8 x 8 HARDWARE MULTIPLIER
9.1 Introduction
All PIC18 devices include an 8 x 8 hardware multiplier
as part of the ALU. The multiplier performs an unsigned
operation and yields a 16-bit result that is stored in the
product register pair, PRODH:PRODL. The multiplier’s
operation does not affect any flags in the STATUS
register.
Making multiplication a hardware operation allows it to
be completed in a single instruction cycle. This has the
advantages of higher computational throughput and
reduced code size for multiplication algorithms and
allows PIC18 devices to be used in many applications
previously reserved for digital-signal processors. A
comparison of various hardware and software multiply
operations, along with the savings in memory and
execution time, is shown in Ta bl e 9 - 1 .
9.2 Operation
Example 9-1 shows the instruction sequence for an 8 x 8
unsigned multiplication. Only one instruction is required
when one of the arguments is already loaded in the
WREG register.
Example 9-2 shows the sequence to do an 8 x 8 signed
multiplication. To account for the sign bits of the argu-
ments, each argument’s Most Significant bit (MSb) is
tested and the appropriate subtractions are done.
EXAMPLE 9-1: 8 x 8 UNSIGNED
MULTIPLY ROUTINE
EXAMPLE 9-2: 8 x 8 SIGNED MULTIPLY
ROUTINE
TABLE 9-1: PERFORMANCE COMPARISON FOR VARIOUS MULTIPLY OPERATIONS
MOVF ARG1, W ;
MULWF ARG2 ; ARG1 * ARG2 ->
; PRODH:PRODL
MOVF ARG1, W
MULWF ARG2 ; ARG1 * ARG2 ->
; PRODH:PRODL
BTFSC ARG2, SB ; Test Sign Bit
SUBWF PRODH, F ; PRODH = PRODH
; - ARG1
MOVF ARG2, W
BTFSC ARG1, SB ; Test Sign Bit
SUBWF PRODH, F ; PRODH = PRODH
; - ARG2
Routine Multiply Method
Program
Memory
(Words)
Cycles
(Max)
Time
@ 64 MHz @ 48 MHz @ 10 MHz @ 4 MHz
8 x 8 Unsigned Without Hardware Multiply 13 69 4.3 s5.7 s27.6 s69 s
Hardware Multiply 1 1 62.5 ns 83.3 ns 400 ns 1 s
8 x 8 Signed Without Hardware Multiply 33 91 5.6 s7.5 s36.4 s91 s
Hardware Multiply 6 6 375 ns 500 ns 2.4 s6 s
16 x 16
Unsigned
Without Hardware Multiply 21 242 15.1 s20.1 s96.8 s 242 s
Hardware Multiply 28 28 1.7 s2.3 s11.2 s28 s
16 x 16 Signed Without Hardware Multiply 52 254 15.8 s21.2 s 101.6 s 254 s
Hardware Multiply 35 40 2.5 s3.3 s16.0 s40 s
PIC18F97J94 FAMILY
DS30575A-page 166 2012 Microchip Technology Inc.
Example 9-3 shows the sequence to do a 16 x 16
unsigned multiplication. Equation 9-1 shows the
algorithm that is used. The 32-bit result is stored in four
registers (RES3:RES0).
EQUATION 9-1: 16 x 16 UNSIGNED
MULTIPLICATION
ALGORITHM
EXAMPLE 9-3: 16 x 16 UNSIGNED
MULTIPLY ROUTINE
Example 9-4 shows the sequence to do a 16 x 16
signed multiply. Equation 9-2 shows the algorithm
used. The 32-bit result is stored in four registers
(RES3:RES0). To account for the sign bits of the
arguments, the MSb for each argument pair is tested
and the appropriate subtractions are done.
EQUATION 9-2: 16 x 16 SIGNED
MULTIPLICATION
ALGORITHM
EXAMPLE 9-4: 16 x 16 SIGNED
MULTIPLY ROUTINE
RES3:RES0 = ARG1H:ARG1L ARG2H:ARG2L
= (ARG1H ARG2H 216) +
(ARG1H ARG2L 28) +
(ARG1L ARG2H 28) +
(ARG1L ARG2L)
MOVF ARG1L, W
MULWF ARG2L ; ARG1L * ARG2L->
; PRODH:PRODL
MOVFF PRODH, RES1 ;
MOVFF PRODL, RES0 ;
;
MOVF ARG1H, W
MULWF ARG2H ; ARG1H * ARG2H->
; PRODH:PRODL
MOVFF PRODH, RES3 ;
MOVFF PRODL, RES2 ;
;
MOVF ARG1L, W
MULWF ARG2H ; ARG1L * ARG2H->
; PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross
MOVF PRODH, W ; products
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
;
MOVF ARG1H, W ;
MULWF ARG2L ; ARG1H * ARG2L->
; PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross
MOVF PRODH, W ; products
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
RES3:RES0= ARG1H:ARG1L ARG2H:ARG2L
= (ARG1H ARG2H 216) +
(ARG1H ARG2L 28) +
(ARG1L ARG2H 28) +
(ARG1L ARG2L) +
(-1 ARG2H<7> ARG1H:ARG1L 216) +
(-1 ARG1H<7> ARG2H:ARG2L 216)
MOVF ARG1L, W
MULWF ARG2L ; ARG1L * ARG2L ->
; PRODH:PRODL
MOVFF PRODH, RES1 ;
MOVFF PRODL, RES0 ;
;
MOVF ARG1H, W
MULWF ARG2H ; ARG1H * ARG2H ->
; PRODH:PRODL
MOVFF PRODH, RES3 ;
MOVFF PRODL, RES2 ;
;
MOVF ARG1L, W
MULWF ARG2H ; ARG1L * ARG2H ->
; PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross
MOVF PRODH, W ; products
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
;
MOVF ARG1H, W ;
MULWF ARG2L ; ARG1H * ARG2L ->
; PRODH:PRODL
MOVF PRODL, W ;
ADDWF RES1, F ; Add cross
MOVF PRODH, W ; products
ADDWFC RES2, F ;
CLRF WREG ;
ADDWFC RES3, F ;
;
BTFSS ARG2H, 7 ; ARG2H:ARG2L neg?
BRA SIGN_ARG1 ; no, check ARG1
MOVF ARG1L, W ;
SUBWF RES2 ;
MOVF ARG1H, W ;
SUBWFB RES3 ;
SIGN_ARG1
BTFSS ARG1H, 7 ; ARG1H:ARG1L neg?
BRA CONT_CODE ; no, done
MOVF ARG2L, W ;
SUBWF RES2 ;
MOVF ARG2H, W ;
SUBWFB RES3
;
CONT_CODE
:
2012 Microchip Technology Inc. DS30575A-page 167
PIC18F97J94 FAMILY
10.0 INTERRUPTS
Members of the PIC18F97J94 family of devices have
multiple interrupt sources and an interrupt priority
feature that allows most interrupt sources to be
assigned a high-priority level or a low-priority level. The
high-priority interrupt vector is at 0008h and the
low-priority interrupt vector is at 0018h. High-priority
interrupt events will interrupt any low-priority interrupts
that may be in progress.
The registers for controlling interrupt operation are:
• RCON
•INTCON
• INTCON2
• INTCON3
• PIR1, PIR2, PIR3, PIR4, PIR5 and PIR6
• PIE1, PIE2, PIE3, PIE4, PIE5 and PIE6
• IPR1, IPR2, IPR3, IPR5, IPR5 and IPR6
It is recommended that the Microchip header files, sup-
plied with MPLAB® IDE, be used for the symbolic bit
names in these registers. This allows the
assembler/compiler to automatically take care of the
placement of these bits within the specified register.
In general, interrupt sources have three bits to control
their operation. They are:
•Flag bit – Indicating that an interrupt event
occurred
•Enable bit – Enabling program execution to
branch to the interrupt vector address when the
flag bit is set
•Priority bit – Specifying high priority or low priority
10.1 Mid-Range Compatibility
When the IPEN bit is cleared (default state), the
interrupt priority feature is disabled and interrupts are
compatible with PIC® microcontroller mid-range
devices. In Compatibility mode, the interrupt priority
bits of the IPRx registers have no effect. The
PEIE/GIEL bit of the INTCON register is the global
interrupt enable for the peripherals. The PEIE/GIEL bit
disables only the peripheral interrupt sources and
enables the peripheral interrupt sources when the
GIE/GIEH bit is also set. The GIE/GIEH bit of the
INTCON register is the global interrupt enable which
enables all non-peripheral interrupt sources and
disables all interrupt sources, including the
peripherals. All interrupts branch to address 0008h in
Compatibility mode.
10.2 10.2 Interrupt Priority
The interrupt priority feature is enabled by setting the
IPEN bit of the RCON register. When interrupt priority
is enabled the GIE/GIEH and PEIE/GIEL global
interrupt enable bits of Compatibility mode are
replaced by the GIEH high priority, and GIEL low
priority, global interrupt enables. When set, the GIEH
bit of the INTCON register enables all interrupts that
have their associated IPRx register or INTCONx
register priority bit set (high priority). When clear, the
GIEH bit disables all interrupt sources including those
selected as low priority. When clear, the GIEL bit of
the INTCON register disables only the interrupts that
have their associated priority bit cleared (low priority).
When set, the GIEL bit enables the low priority
sources when the GIEH bit is also set. When the
interrupt flag, enable bit and appropriate Global
Interrupt Enable (GIE) bit are all set, the interrupt will
vector immediately to address 0008h for high priority,
or 0018h for low priority, depending on level of the
interrupting source’s priority bit. Individual interrupts
can be disabled through their corresponding interrupt
enable bits.
10.3 10.3 Interrupt Response
When an interrupt is responded to, the Global Interrupt
Enable bit is cleared to disable further interrupts. The
GIE/GIEH bit is the global interrupt enable when the
IPEN bit is cleared. When the IPEN bit is set, enabling
interrupt priority levels, the GIEH bit is the high priority
global interrupt enable and the GIEL bit is the low
priority global interrupt enable. High priority interrupt
sources can interrupt a low priority interrupt. Low
priority interrupts are not processed while high priority
interrupts are in progress.
The return address is pushed onto the stack and the
PC is loaded with the interrupt vector address (0008h
or 0018h). Once in the Interrupt Service Routine, the
source(s) of the interrupt can be determined by polling
the interrupt flag bits in the INTCONx and PIRx
registers. The interrupt flag bits must be cleared by
software before re-enabling interrupts to avoid
repeating the same interrupt.
The “return from interrupt” instruction, RETFIE, exits
the interrupt routine and sets the GIE/GIEH bit (GIEH
or GIEL if priority levels are used), which re-enables
interrupts.
PIC18F97J94 FAMILY
DS30575A-page 168 2012 Microchip Technology Inc.
For external interrupt events, such as the INT pins or
the PORTB interrupt-on-change, the interrupt latency
will be three to four instruction cycles. The exact
latency is the same for one-cycle or two-cycle
instructions. Individual interrupt flag bits are set,
regardless of the status of their corresponding enable
bits or the Global Interrupt Enable bit.
Note: Do not use the MOVFF instruction to modify
any of the Interrupt Control registers while
any interrupt is enabled. Doing so may
cause erratic microcontroller behavior.
2012 Microchip Technology Inc. DS30575A-page 169
PIC18F97J94 FAMILY
FIGURE 10-1: PIC18F97J94 FAMILY INTERRUPT LOGIC
TMR0IE
GIE/GIEH
PEIE/GIEL
Wake-up if in
Interrupt to CPU
Vector to Location
0008h
INT2IF
INT2IE
INT2IP
INT1IF
INT1IE
INT1IP
TMR0IF
TMR0IE
TMR0IP
RBIF
RBIE
RBIP
IPEN
TMR0IF
TMR0IP
INT1IF
INT1IE
INT1IP
INT2IF
INT2IE
INT2IP
RBIF
RBIE
RBIP
INT0IF
INT0IE
PEIE/GIEL
Interrupt to CPU
Vector to Location
IPEN
IPEN
0018h
PIR1<7:0>
PIE1<7:0>
IPR1<7:0>
High-Priority Interrupt Generation
Low-Priority Interrupt Generation
Idle or Sleep modes
GIE/GIEH
INT3IF
INT3IE
INT3IP
INT3IF
INT3IE
INT3IP
PIR2<7,5:0>
PIE2<7,5:0>
IPR2<7,5:0>
PIR3<7,5>
PIE3<7,5>
IPR3<7,5>
PIR1<7:0>
PIE1<7:0>
IPR1<7:0>
PIR2<7, 5:0>
PIE2<7, 5:0>
IPR2<7, 5:0>
PIR3<7, 5:0>
PIE3<7, 5:0>
IPR3<7, 5:0>
IPEN
PIR4<7:0>
PIE4<7:0>
IPR4<7:0>
PIR5<7:0>
PIE5<7:0>
IPR5<7:0>
PIR4<7:0>
PIE4<7:0>
IPR4<7:0>
PIR5<7:0>
PIE5<7:0>
IPR5<7:0>
PIR6<7:0>
PIE6<7:0>
IPR6<7:0>
PIR6<7:0>
PIE6<7:0>
IPR6<7:0>
PIC18F97J94 FAMILY
DS30575A-page 170 2012 Microchip Technology Inc.
10.4 INTCON Registers
The INTCON registers are readable and writable
registers that contain various enable, priority and flag
bits.
Note: Interrupt flag bits are set when an interrupt
condition occurs regardless of the state of
its corresponding enable bit or the Global
Interrupt Enable bit. User software should
ensure the appropriate interrupt flag bits
are clear prior to enabling an interrupt.
This feature allows for software polling.
REGISTER 10-1: INTCON: INTERRUPT CONTROL REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R-0
GIE/GIEH PEIE/GIEL TMR0IE INT0IE IOCIE TMR0IF INT0IF IOCIF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 GIE/GIEH: Global Interrupt Enable bit
When IPEN = 0:
1 = Enables all unmasked interrupts
0 = Disables all interrupts including peripherals
When IPEN = 1:
1 = Enables all high-priority interrupts
0 = Disables all interrupts including low priority
bit 6 PEIE/GIEL: Peripheral Interrupt Enable bit
When IPEN = 0:
1 = Enables all unmasked peripheral interrupts
0 = Disables all peripheral interrupts
When IPEN = 1:
1 = Enables all low-priority peripheral interrupts
0 = Disables all low-priority peripheral interrupts
bit 5 TMR0IE: TMR0 Overflow Interrupt Enable bit
1 = Enables the TMR0 overflow interrupt
0 = Disables the TMR0 overflow interrupt
bit 4 INT0IE: INT0 External Interrupt Enable bit
1 = Enables the INT0 external interrupt
0 = Disables the INT0 external interrupt
bit 3 IOCIE: I/O Change Interrupt Enable bit
1 = Enables the I/O port change interrupt
0 = Disables the I/O port change interrupt
bit 2 TMR0IF: TMR0 Overflow Interrupt Flag bit
1 = TMR0 register has overflowed (must be cleared in software)
0 = TMR0 register has not overflowed
bit 1 INT0IF: INT0 External Interrupt Flag bit
1 = The INT0 external interrupt occurred (must be cleared in software)
0 = The INT0 external interrupt did not occur
bit 0 IOCIF: I/O Port Change Interrupt Flag bit
1 = At least one of the IOC<7:0> pins changed state (must be cleared by clearing all the IOCF bits in
the IOC module)
0 = None of the IOC<7:0> pins have changed state
2012 Microchip Technology Inc. DS30575A-page 171
PIC18F97J94 FAMILY
REGISTER 10-2: INTCON2: INTERRUPT CONTROL REGISTER 2
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
RBPU INTEDG0 INTEDG1 INTEDG2 INTEDG3 TMR0IP INT3IP IOCIP
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 RBPU: PORTB Pull-up Enable bit
1 = All PORTB pull-ups are disabled
0 = PORTB pull-ups are enabled by individual port latch values
bit 6 INTEDG0: External Interrupt 0 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 5 INTEDG1: External Interrupt 1 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 4 INTEDG2: External Interrupt 2 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 3 INTEDG3: External Interrupt 3 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 2 TMR0IP: TMR0 Overflow Interrupt Priority bit
1 =High priority
0 = Low priority
bit 1 INT3IP: INT3 External Interrupt Priority bit
1 =High priority
0 = Low priority
bit 0 IOCIP: RB Port Change Interrupt Priority bit
1 =High priority
0 = Low priority
Note: Interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding
enable bit or the Global Interrupt Enable bit. User software should ensure the appropriate interrupt flag bits
are clear prior to enabling an interrupt. This feature allows for software polling.
PIC18F97J94 FAMILY
DS30575A-page 172 2012 Microchip Technology Inc.
REGISTER 10-3: INTCON3: INTERRUPT CONTROL REGISTER 3
R/W-1 R/W-1 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
INT2IP INT1IP INT3IE INT2IE INT1IE INT3IF INT2IF INT1IF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 INT2IP: INT2 External Interrupt Priority bit
1 =High priority
0 = Low priority
bit 6 INT1IP: INT1 External Interrupt Priority bit
1 =High priority
0 = Low priority
bit 5 INT3IE: INT3 External Interrupt Enable bit
1 = Enables the INT3 external interrupt
0 = Disables the INT3 external interrupt
bit 4 INT2IE: INT2 External Interrupt Enable bit
1 = Enables the INT2 external interrupt
0 = Disables the INT2 external interrupt
bit 3 INT1IE: INT1 External Interrupt Enable bit
1 = Enables the INT1 external interrupt
0 = Disables the INT1 external interrupt
bit 2 INT3IF: INT3 External Interrupt Flag bit
1 = The INT3 external interrupt occurred (must be cleared in software)
0 = The INT3 external interrupt did not occur
bit 1 INT2IF: INT2 External Interrupt Flag bit
1 = The INT2 external interrupt occurred (must be cleared in software)
0 = The INT2 external interrupt did not occur
bit 0 INT1IF: INT1 External Interrupt Flag bit
1 = The INT1 external interrupt occurred (must be cleared in software)
0 = The INT1 external interrupt did not occur
Note: Interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding
enable bit or the Global Interrupt Enable bit. User software should ensure the appropriate interrupt flag bits
are clear prior to enabling an interrupt. This feature allows for software polling.
2012 Microchip Technology Inc. DS30575A-page 173
PIC18F97J94 FAMILY
10.5 PIR Registers
The PIR registers contain the individual flag bits for the
peripheral interrupts. Due to the number of peripheral
interrupt sources, there are six Peripheral Interrupt
Request (Flag) registers (PIR1 through PIR5).
Note 1: Interrupt flag bits are set when an
interrupt condition occurs regardless of
the state of its corresponding enable bit or
the Global Interrupt Enable bit, GIE
(INTCON<7>).
2: User software should ensure the
appropriate interrupt flag bits are cleared
prior to enabling an interrupt and after
servicing that interrupt.
REGISTER 10-4: PIR1: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 1
R/W-0 R/W-0 R-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0
PSPIF ADIF RC1IF TX1IF SSP1IF TMR1GIF TMR2IF TMR1IF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 PSPIF: Parallel Slave Port Read/Write Interrupt Flag bit
1 = A read or write operation has taken place (must be cleared in software)
0 = No read or write operation has occurred
bit 6 ADIF: A/D Converter Interrupt Flag bit
1 = An A/D conversion completed (must be cleared in software)
0 = The A/D conversion is not complete
bit 5 RC1IF: EUSART1 Receive Interrupt Flag bit
1 = The EUSART1 receive buffer, RCREG1, is full (cleared when RCREG1 is read)
0 = The EUSART1 receive buffer is empty
bit 4 TX1IF: EUSART1 Transmit Interrupt Flag bit
1 = The EUSART1 transmit buffer, TXREG1, is empty (cleared when TXREG1 is written)
0 = The EUSART1 transmit buffer is full
bit 3 SSP1IF: Master Synchronous Serial Port 1 Interrupt Flag bit
1 = The transmission/reception is complete (must be cleared in software)
0 = Waiting to transmit/receive
bit 2 TMR1GIF: Timer1 Gate Interrupt Flag bit
1 = Timer gate interrupt occurred (must be cleared in software)
0 = No timer gate interrupt occurred
bit 1 TMR2IF: TMR2 to PR2 Match Interrupt Flag bit
1 = TMR2 to PR2 match occurred (must be cleared in software)
0 = No TMR2 to PR2 match occurred
bit 0 TMR1IF: TMR1 Overflow Interrupt Flag bit
1 = TMR1 register overflowed (must be cleared in software)
0 = TMR1 register did not overflow
PIC18F97J94 FAMILY
DS30575A-page 174 2012 Microchip Technology Inc.
REGISTER 10-5: PIR2: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 2
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
OSCFIF SSP2IF BCL2IF USBIF BCL1IF HLVDIF TMR3IF TMR3GIF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 OSCFIF: Oscillator Fail Interrupt Flag bit
1 = Device oscillator failed, clock input has changed to INTOSC (bit must be cleared in software)
0 = Device clock operating
bit 6 SSP2IF: Master Synchronous Serial Port 2 Interrupt Flag bit
1 = The transmission/reception is complete (must be cleared in software)
0 = Waiting to transmit/receive
bit 5 BCL2IF: Bus Collision Interrupt Flag bit
1 = A bus collision has occurred while the MSSP1 module configured in I2C™ master was transmitting
(must be cleared in software)
0 = No bus collision occurred
bit 4 USBIF: Oscillator Fail Interrupt Flag bit
1 = USB requested an interrupt (must be cleared in software)
0 = No USB interrupt request
bit 3 BCL1IF: Bus Collision Interrupt Flag bit
1 = A bus collision occurred (bit must be cleared in software)
0 = No bus collision occurred
bit 2 HLVDIF: High/Low-Voltage Detect Interrupt Flag bit
1 = A low-voltage condition occurred (bit must be cleared in software)
0 = The device voltage is above the regulator’s low-voltage trip point
bit 1 TMR3IF: TMR3 Overflow Interrupt Flag bit
1 = TMR3 register overflowed (bit must be cleared in software)
0 = TMR3 register did not overflow
bit 0 TMR3GIF: TMR3 Gate Interrupt Flag bit
1 = Timer gate interrupt occurred (bit must be cleared in software)
0 = No timer gate interrupt occurred
2012 Microchip Technology Inc. DS30575A-page 175
PIC18F97J94 FAMILY
REGISTER 10-6: PIR3: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 3
R/W-0 R/W-0 R-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0
TMR5GIF LCDIF RC2IF TX2IF CTMUIF CCP2IF CCP1IF RTCCIF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 TMR5GIF: TMR5 Gate Interrupt Flag bits
1 = TMR gate interrupt occurred (must be cleared in software)
0 = No TMR gate occurred
bit 6 LCDIF: LCD Interrupt Flag bit
1 = A write is allowed to the Segment Data Registers
0 = A write is not allowed to the Segment Data Register
bit 5 RC2IF: EUSART2 Receive Interrupt Flag bit
1 = The EUSART2 receive buffer, RCREG2, is full (cleared when RCREG2 is read)
0 = The EUSART2 receive buffer is empty
bit 4 TX2IF: EUSART2 Transmit Interrupt Flag bit
1 = The EUSART2 transmit buffer, TXREG2, is empty (cleared when TXREG2 is written)
0 = The EUSART2 transmit buffer is full
bit 3 CTMUIF: CTMU Interrupt Flag bit
1 = CTMU interrupt occurred (must be cleared in software)
0 = No CTMU interrupt occurred
bit 2 CCP2IF: CCP2 Interrupt Flag bit
Capture mode:
1 = A TMR1/TMR3 register capture occurred (must be cleared in software)
0 = No TMR1/TMR3 register capture occurred
Compare mode:
1 = A TMR1/TMR3 register compare match occurred (must be cleared in software)
0 = No TMR1/TMR3 register compare match occurred
PWM mode:
Unused in this mode.
bit 1 CCP1IF: ECCP1 Interrupt Flag bit
Capture mode:
1 = A TMR1/TMR3 register capture occurred (must be cleared in software)
0 = No TMR1/TMR3 register capture occurred
Compare mode:
1 = A TMR1/TMR3 register compare match occurred (must be cleared in software)
0 = No TMR1/TMR3 register compare match occurred
PWM mode:
Unused in this mode.
bit 0 RTCCIF: RTCC Interrupt Flag bit
1 = RTCC interrupt occurred (must be cleared in software)
0 = No RTCC interrupt occurred
PIC18F97J94 FAMILY
DS30575A-page 176 2012 Microchip Technology Inc.
REGISTER 10-7: PIR4: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 4
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CCP10IF CCP9IF CCP8IF CCP7IF CCP6IF CCP5IF CCP4IF ECCP3IF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CCP10IF: CCP10 Interrupt Flag bits
Capture mode:
1 = A TMR register capture occurred (bit must be cleared in software)
0 = No TMR register capture occurred
Compare mode:
1 = A TMR register compare match occurred (must be cleared in software)
0 = No TMR register compare match occurred
PWM mode:
Not used in PWM mode.
bit 6 CCP9IF: CCP9 Interrupt Flag bits
Capture mode:
1 = A TMR register capture occurred (bit must be cleared in software)
0 = No TMR register capture occurred
Compare mode:
1 = A TMR register compare match occurred (must be cleared in software)
0 = No TMR register compare match occurred
PWM mode:
Not used in PWM mode.
bit 5 CCP8IF: CCP8 Interrupt Flag bits
Capture mode:
1 = A TMR register capture occurred (bit must be cleared in software)
0 = No TMR register capture occurred
Compare mode:
1 = A TMR register compare match occurred (must be cleared in software)
0 = No TMR register compare match occurred
PWM mode:
Not used in PWM mode.
bit 4 CCP7IF: CCP7 Interrupt Flag bit
1 = Interrupt Flag bits
Capture mode:
1 = A TMR register capture occurred (bit must be cleared in software)
0 = No TMR register capture occurred
Compare mode:
1 = A TMR register compare match occurred (must be cleared in software)
0 = No TMR register compare match occurred
PWM mode:
Not used in PWM mode.
2012 Microchip Technology Inc. DS30575A-page 177
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bit 3 CCP6IF: CCP6 Interrupt Flag bits
Capture mode:
1 = A TMR register capture occurred (bit must be cleared in software)
0 = No TMR register capture occurred
Compare mode:
1 = A TMR register compare match occurred (must be cleared in software)
0 = No TMR register compare match occurred
PWM mode:
Not used in PWM mode.
bit 2 CCP5IF: CCP5 Interrupt Flag bits
Capture mode:
1 = A TMR register capture occurred (bit must be cleared in software)
0 = No TMR register capture occurred
Compare mode:
1 = A TMR register compare match occurred (must be cleared in software)
0 = No TMR register compare match occurred
PWM mode:
Not used in PWM mode.
bit 1 CCP4IF: CCP4 Interrupt Flag bits
Capture mode:
1 = A TMR register capture occurred (bit must be cleared in software)
0 = No TMR register capture occurred
Compare mode:
1 = A TMR register compare match occurred (must be cleared in software)
0 = No TMR register compare match occurred
PWM mode:
Not used in PWM mode.
bit 0 ECCP3IF: ECCP3 Interrupt Flag bits
Capture mode:
1 = A TMR register capture occurred (bit must be cleared in software)
0 = No TMR register capture occurred
Compare mode:
1 = A TMR register compare match occurred (must be cleared in software)
0 = No TMR register compare match occurred
PWM mode:
Not used in PWM mode.
REGISTER 10-7: PIR4: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 4 (CONTINUED)
PIC18F97J94 FAMILY
DS30575A-page 178 2012 Microchip Technology Inc.
REGISTER 10-8: PIR5: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 5
U-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0
— ACTORSIF ACTLOCKIF TMR8IF — TMR6IF TMR5IF TMR4IF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6 ACTORSIF: Active Clock Tuning Out-of-Range Interrupt Flag bit
1 = Active clock tuning out-of-range occurred
0 = Active tuning out-of-range did not occur
bit 5 ACTLOCKIF: Active Clock Tuning Lock Interrupt Flag bit
1 = Active clock tuning lock/unlock occurred
0 = Active clock tuning lock/unlock did not occur
bit 4 TMR8IF: TMR8 to PR8 Match Interrupt Flag bit
1 = TMR8 to PR8 match occurred (must be cleared in software)
0 = No TMR8 to PR8 match occurred
bit 3 Unimplemented: Read as ‘0’
bit 2 TMR6IF: TMR6 to PR6 Match Interrupt Flag bit
1 = TMR6 to PR6 match occurred (must be cleared in software)
0 = No TMR6 to PR6 match occurred
bit 1 TMR5IF: TMR5 Overflow Interrupt Flag bit
1 = TMR5 register overflowed (must be cleared in software)
0 = TMR5 register did not overflow
bit 0 TMR4IF: TMR4 to PR4 Match Interrupt Flag bit
1 = TMR4 to PR4 match occurred (must be cleared in software)
0 = No TMR4 to PR4 match occurred
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REGISTER 10-9: PIR6: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 6
R/W-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0
RC4IF TX4IF RC3IF TX3IF — CMP3IF CMP2IF CMP1IF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 RC4IF: EUSART4 Receive Interrupt Flag bit
1 = The EUSART4 receive buffer is full (cleared by reading RCREG4)
0 = The EUSART4 receive buffer is empty
bit 6 TX4IF: EUSART4 Transmit Interrupt Flag bit
1 = The EUSART4 transmit buffer is empty (cleared by writing to TXREG4)
0 = The EUSART4 transmit buffer is full
bit 5 RC3IF: EUSART3 Receive Interrupt Flag bit
1 = The EUSART3 receive buffer is full (cleared by reading RCREG3)
0 = The EUSART3 receive buffer is empty
bit 4 TX3IF: EUSART3 Transmit Interrupt Flag bit
1 = The EUSART3 transmit buffer is empty (cleared by writing to TXREG3)
0 = The EUSART3 transmit buffer is full
bit 3 Unimplemented: Read as ‘0’
bit 2 CMP3IF: CMP3 Interrupt Flag bit
1 = CMP3 interrupt occurred (must be cleared in software)
0 = No CMP3 interrupt occurred
bit 1 CMP2IF: CMP2 Interrupt Flag bit
1 = CMP2 interrupt occurred (must be cleared in software)
0 = No CMP2 interrupt occurred
bit 0 CMP1IF: CM1 Interrupt Flag bit
1 = CMP1 interrupt occurred (must be cleared in software)
0 = No CMP1 interrupt occurred
PIC18F97J94 FAMILY
DS30575A-page 180 2012 Microchip Technology Inc.
10.6 PIE Registers
The PIE registers contain the individual enable bits for
the peripheral interrupts. Due to the number of
peripheral interrupt sources, there are six Peripheral
Interrupt Enable registers (PIE1 through PIE6). When
IPEN (RCON<7>) = 0, the PEIE bit must be set to
enable any of these peripheral interrupts.
REGISTER 10-10: PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
PSPIE ADIE RC1IE TX1IE SSP1IE TMR1GIE TMR2IE TMR1IE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 PSPIE: Parallel Slave Port Read/Write Interrupt Enable bit
1 = Enables the PSP read/write interrupt
0 = Disables the PSP read/write interrupt
bit 6 ADIE: A/D Converter Interrupt Enable bit
1 = Enables the A/D interrupt
0 = Disables the A/D interrupt
bit 5 RC1IE: EUSART1 Receive Interrupt Enable bit
1 = Enables the EUSART1 receive interrupt
0 = Disables the EUSART1 receive interrupt
bit 4 TX1IE: EUSART1 Transmit Interrupt Enable bit
1 = Enables the EUSART1 transmit interrupt
0 = Disables the EUSART1 transmit interrupt
bit 3 SSP1IE: Master Synchronous Serial Port 1 Interrupt Enable bit
1 = Enables the MSSP1 interrupt
0 = Disables the MSSP1 interrupt
bit 2 TMR1GIE: TMR1 Gate Interrupt Enable bit
1 = Enables the gate
0 = Disables the gate
bit 1 TMR2IE: TMR2 to PR2 Match Interrupt Enable bit
1 = Enables the TMR2 to PR2 match interrupt
0 = Disables the TMR2 to PR2 match interrupt
bit 0 TMR1IE: TMR1 Overflow Interrupt Enable bit
1 = Enables the TMR1 overflow interrupt
0 = Disables the TMR1 overflow interrupt
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REGISTER 10-11: PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
OSCFIE SSP2IE BCL2IE USBIE BCL1IE HLVDIE TMR3IE TMR3GIE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 OSCFIE: Oscillator Fail Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 6 SSP2IE: Master Synchronous Serial Port 2 Interrupt Enable bit
1 = Enables the MSSP2 interrupt
0 = Disables the MSSP2 interrupt
bit 5 BCL2IE: Bus Collision Interrupt Enable bit (MSSP)
1 = Enabled
0 = Disabled
bit 4 USBIE: USB Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 3 BCLIE: Bus Collision Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 2 HLVDIE: High/Low-Voltage Detect Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 1 TMR3IE: TMR3 Overflow Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 0 TMR3GIE: Timer3 Gate Interrupt Enable bit
1 = Enabled
0 = Disabled
PIC18F97J94 FAMILY
DS30575A-page 182 2012 Microchip Technology Inc.
REGISTER 10-12: PIE3: PERIPHERAL INTERRUPT ENABLE REGISTER 3
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
TMR5GIE LCDIE RC2IE TX2IE CTMUIE CCP2IE CCP1IE RTCCIE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 TMR5GIE: TMR5 Gate Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 6 LCDIE: LCD Ready Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 5 RC2IE: EUSART2 Receive Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 4 TX2IE: EUSART2 Transmit Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 3 CTMUIE: CTMU Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 2 CCP2IE: CCP2 Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 1 CCP1IE: ECCP1 Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 0 RTCCIE: RTCC Interrupt Enable bit
1 = Enabled
0 = Disabled
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REGISTER 10-13: PIE4: PERIPHERAL INTERRUPT ENABLE REGISTER 4
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CCP10IE CCP9IE CCP8IE CCP7IE CCP6IE CCP5IE CCP4IE ECCP3IE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CCP10IE: CCP10 Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 6 CCP9IE: CCP9 Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 5 CCP8IE: CCP8 Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 4 CCP7IE: CCP7 Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 3 CCP6IE: CCP6 Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 2 CCP5IE: CCP5 Interrupt Flag bit
1 = Enabled
0 =Disabled
bit 1 CCP4IE: CCP4 Interrupt Flag bit
1 = Enabled
0 =Disabled
bit 0 ECCP3IE: ECCP3 Interrupt Flag bit
1 = Enabled
0 =Disabled
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DS30575A-page 184 2012 Microchip Technology Inc.
REGISTER 10-14: PIE5: PERIPHERAL INTERRUPT ENABLE REGISTER 5
U-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0
— ACTORSIE ACTLOCKIE TMR8IE — TMR6IE TMR5IE TMR4IE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6 ACTORSIE: Active Clock Tuning Out-of-Range Interrupt Enable bit
1 = Enables the active clock tuning out-of-range interrupt
0 = Disables the active clock tuning out-of-range interrupt
bit 5 ACTLOCKIE: Active Clock Tuning Lock Interrupt Enable bit
1 = Enables the active clock tuning lock/unlock interrupt
0 = Disables the active clock tuning lock/unlock interrupt
bit 4 TMR8IE: TMR8 to PR8 Match Interrupt Enable bit
1 = Enables the TMR8 to PR8 match interrupt
0 = Disables the TMR8 to PR8 match interrupt
bit 3 Unimplemented: Read as ‘0’
bit 2 TMR6IE: TMR6 to PR6 Match Interrupt Enable bit
1 = Enables the TMR6 to PR6 match interrupt
0 = Disables the TMR6 to PR6 match interrupt
bit 1 TMR5IE: TMR5 Overflow Interrupt Enable bit
1 = Enables the TMR5 overflow interrupt
0 = Disables the TMR5 overflow interrupt
bit 0 TMR4IE: TMR4 to PR4 Match Interrupt Enable bit
1 = Enables the TMR4 to PR4 match interrupt
0 = Disables the TMR4 to PR4 match interrupt
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REGISTER 10-15: PIE6: PERIPHERAL INTERRUPT ENABLE REGISTER 6
R/W-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0
RC4IE TX4IE RC3IE TX3IE — CMP3IE CMP2IE CMP1IE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 RC4IE: EUSART4 Receive Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 6 TX4IE: EUSART4 Transmit Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 5 RC34IE: EUSART3 Receive Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 4 TX3IE: EUSART3 Transmit Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 3 Unimplemented: Read as ‘0’
bit 2 CMP3IE: Comparator 3 Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 1 CMP2IE: Comparator 2 Interrupt Enable bit
1 = Enabled
0 =Disabled
bit 0 CMP1IE: Comparator 1 Interrupt Enable bit
1 = Enabled
0 =Disabled
PIC18F97J94 FAMILY
DS30575A-page 186 2012 Microchip Technology Inc.
10.7 IPR Registers
The IPR registers contain the individual priority bits for
the peripheral interrupts. Due to the number of
peripheral interrupt sources, there are six Peripheral
Interrupt Priority registers (IPR1 through IPR6). Using
the priority bits requires that the Interrupt Priority
Enable (IPEN) bit (RCON<7>) be set.
REGISTER 10-16: IPR1: PERIPHERAL INTERRUPT PRIORITY REGISTER 1
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
PSPIP ADIP RC1IP TX1IP SSP1IP TMR1GIP TMR2IP TMR1IP
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 PSPIP: Parallel Slave Port Read/Write Interrupt Priority bit
1 =High priority
0 = Low priority
bit 6 ADIP: A/D Converter Interrupt Priority bit
1 =High priority
0 = Low priority
bit 5 RC1IP: EUSART1 Receive Interrupt Priority bit
1 =High priority
0 = Low priority
bit 4 TX1IP: EUSART1 Transmit Interrupt Priority bit
1 =High priority
0 = Low priority
bit 3 SSP1IP: Master Synchronous Serial Port 1 Interrupt Priority bit
1 =High priority
0 = Low priority
bit 2 TMR1GIP: Timer1 Gate Interrupt Priority bit
1 =High priority
0 = Low priority
bit 1 TMR2IP: TMR2 to PR2 Match Interrupt Priority bit
1 =High priority
0 = Low priority
bit 0 TMR1IP: TMR1 Overflow Interrupt Priority bit
1 =High priority
0 = Low priority
2012 Microchip Technology Inc. DS30575A-page 187
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REGISTER 10-17: IPR2: PERIPHERAL INTERRUPT PRIORITY REGISTER 2
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
OSCFIP SSP2IP BCL2IP USBIP BCL1IP HLVDIP TMR3IP TMR3GIP
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 OSCFIP: Oscillator Fail Interrupt Priority bit
1 =High priority
0 = Low priority
bit 6 SSP2IP: Master Synchronous Serial Port 2 Interrupt Priority bit
1 =High priority
0 = Low priority
bit 5 BCL2IP: Bus Collision Interrupt Priority bit (MSSP)
1 =High priority
0 = Low priority
bit 4 USBIP: USB Interrupt Priority bit
1 =High priority
0 = Low priority
bit 3 BCL1IP: Bus Collision Interrupt Priority bit
1 =High priority
0 = Low priority
bit 2 HLVDIP: High/Low-Voltage Detect Interrupt Priority bit
1 =High priority
0 = Low priority
bit 1 TMR3IP: TMR3 Overflow Interrupt Priority bit
1 =High priority
0 = Low priority
bit 0 TMR3GIP: TMR3 Gate Interrupt Priority bit
1 =High priority
0 = Low priority
PIC18F97J94 FAMILY
DS30575A-page 188 2012 Microchip Technology Inc.
REGISTER 10-18: IPR3: PERIPHERAL INTERRUPT PRIORITY REGISTER 3
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
TMR5GIP LCDIP RC2IP TX2IP CTMUIP CCP2IP CCP1IP RTCCIP
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 TMR5GIP: TMR5 Gate Interrupt Priority bit
1 =High priority
0 = Low priority
bit 6 LCDIP: LCD Ready Interrupt Priority bit
1 =High priority
0 = Low priority
bit 5 RC2IP: EUSART2 Receive Priority Flag bit
1 =High priority
0 = Low priority
bit 4 TX2IP: EUSART2 Transmit Interrupt Priority bit
1 =High priority
0 = Low priority
bit 3 CTMUIP: CTMU Interrupt Priority bit
1 =High priority
0 = Low priority
bit 2 CCP2IP: CCP2 Interrupt Priority bit
1 =High priority
0 = Low priority
bit 1 CCP1IP: ECCP1 Interrupt Priority bit
1 =High priority
0 = Low priority
bit 0 RTCCIP: RTCC Interrupt Priority bit
1 =High priority
0 = Low priority
2012 Microchip Technology Inc. DS30575A-page 189
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REGISTER 10-19: IPR4: PERIPHERAL INTERRUPT PRIORITY REGISTER 4
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
CCP10IP CCP9IP CCP8IP CCP7IP CCP6IP CCP5IP CCP4IP ECCP3IP
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CCP10IP: CCP10 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6 CCP9IP: CCP9 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5 CCP8IP: CCP8 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 4 CCP7IP: CCP7 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3 CCP6IP: CCP6 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 2 CCP5IP: CCP5 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1 CCP4IP: CCP4 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0 ECCP3IP: ECCP3 Interrupt Priority bits
1 = High priority
0 = Low priority
PIC18F97J94 FAMILY
DS30575A-page 190 2012 Microchip Technology Inc.
REGISTER 10-20: IPR5: PERIPHERAL INTERRUPT PRIORITY REGISTER 5
U-0 R/W-1 R/W-1 R/W-1 U-0 R/W-1 R/W-1 R/W-1
— ACTORSIP ACTLOCKIP TMR8IP — TMR6IP TMR5IP TMR4IP
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6 ACTORSIP: Active Clock Tuning Out-of-Range Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5 ACTLOCKIP: Active Clock Tuning Lock Interrupt Priority bit
1 = High priority
0 = Low priority
bit 4 TMR8IP: TMR8 to PR8 Match Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3 Unimplemented: Read as ‘0’
bit 2 TMR6IP: TMR6 to PR6 Match Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1 TMR5IP: TMR5 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0 TMR4IP: TMR4 to PR4 Match Interrupt Priority bit
1 = High priority
0 = Low priority
2012 Microchip Technology Inc. DS30575A-page 191
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REGISTER 10-21: IPR6: PERIPHERAL INTERRUPT PRIORITY REGISTER 6
R/W-1 R/W-1 R/W-1 R/W-1 U-O R/W-1 R/W-1 R/W-1
RC4IP TX4IP RC3IP TX3IP — CMP3IP CMP2IP CMP1IP
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 RCP4IP: EUSART4 Receive Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6 TX4IP: EUSART4 Transmit Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5 RC3IP: EUSART3 Receive Interrupt Priority bit
1 = High priority
0 = Low priority
bit 4 TX3IP: EUSART3 Transmit Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3 Unimplemented: Read as ‘0’
bit 2 CMP3IP: CMP3 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1 CMP2IP: CMP2 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0 CMP1IP: CMP1 Interrupt Priority bit
1 = High priority
0 = Low priority
PIC18F97J94 FAMILY
DS30575A-page 192 2012 Microchip Technology Inc.
10.8 RCON Register
The RCON register contains bits used to determine the
cause of the last Reset or wake-up from Idle or Sleep
modes. RCON also contains the bit that enables
interrupt priorities (IPEN).
REGISTER 10-22: RCON: RESET CONTROL REGISTER
R/W-0 U-0 R/W-1 R/W-1 R-1 R-1 R/W-0 R/W-0
IPEN —CMRI TO PD POR BOR
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 IPEN: Interrupt Priority Enable bit
1 = Enables priority levels on interrupts
0 = Disables priority levels on interrupts (PIC16CXXX Compatibility mode)
bit 6 Unimplemented: Read as ‘0’
bit 5 CM: Configuration Mismatch Flag bit
1 = A Configuration Mismatch Reset has not occurred
0 = A Configuration Mismatch Reset has occurred (must be subsequently set in software)
bit 4 RI: RESET Instruction Flag bit
For details of bit operation, see Register 5-1.
bit 3 TO: Watchdog Timer Time-out Flag bit
For details of bit operation, see Register 5-1.
bit 2 PD: Power-Down Detection Flag bit
For details of bit operation, see Register 5-1.
bit 1 POR: Power-on Reset Status bit
For details of bit operation, see Register 5-1.
bit 0 BOR: Brown-out Reset Status bit
For details of bit operation, see Register 5-1.
2012 Microchip Technology Inc. DS30575A-page 193
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10.9 INTx Pin Interrupts
External interrupts on the RB0/INT0, RB1/INT1,
RB2/INT2 and RB3/INT3 pins are edge-triggered. If the
corresponding INTEDGx bit in the INTCON2 register is
set (= 1), the interrupt is triggered by a rising edge. If
that bit is clear, the trigger is on the falling edge.
When a valid edge appears on the RBx/INTx pin, the
corresponding flag bit, INTxIF, is set. This interrupt can
be disabled by clearing the corresponding enable bit,
INTxIE. Before re-enabling the interrupt, the flag bit
(INTxIF) must be cleared in software in the Interrupt
Service Routine.
All external interrupts (INT0, INT1, INT2 and INT3) can
wake-up the processor from the power-managed
modes if bit, INTxIE, was set prior to going into the
power-managed modes. If the Global Interrupt Enable
bit (GIE) is set, the processor will branch to the interrupt
vector following wake-up.
The interrupt priority for INT1, INT2 and INT3 is
determined by the value contained in the Interrupt
Priority bits, INT1IP (INTCON3<6>), INT2IP
(INTCON3<7>) and INT3IP (INTCON2<1>).
There is no priority bit associated with INT0. It is always
a high-priority interrupt source.
10.10 TMR0 Interrupt
In 8-bit mode (the default), an overflow in the TMR0
register (FFh 00h) will set flag bit, TMR0IF. In 16-bit
mode, an overflow in the TMR0H:TMR0L register pair
(FFFFh 0000h) will set TMR0IF.
The interrupt can be enabled/disabled by setting/clearing
enable bit, TMR0IE (INTCON<5>). Interrupt priority for
Timer0 is determined by the value contained in the inter-
rupt priority bit, TMR0IP (INTCON2<2>). For further
details on the Timer0 module, see Section 14.0 “Timer0
Module”.
10.11 Edge-Selectable
Interrupt-on-Change
Interrupt-on-change pins are selected via the PPS
register settings and have the option of generating an
interrupt on positive or negative transitions, or both.
Positive edge events are enabled by setting the corre-
sponding bits in the IOCP register, while negative edge
events are enabled by setting the corresponding bits in
the IOCN register. For compatibility with the previous
interrupt-on-change feature, both the IOCP and IOCN
bits should be set. The interrupt can be enabled by
setting/clearing the IOCIE (INTCON<3>) bit. Each
individual pin can be disabled by clearing both of the
corresponding IOCN/IOCP bits. A change event (either
positive or negative edge) will cause the corresponding
IOCF flag to be set.
Interrupt priority for the edge selectable
interrupt-on-change is determined by the interrupt
priority bit, IOCIP (INTCON2<0>).
PIC18F97J94 FAMILY
DS30575A-page 194 2012 Microchip Technology Inc.
REGISTER 10-23: IOCP: INTERRUPT-ON-CHANGE POSITIVE EDGE REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
IOCP7 IOCP6 IOCP5 IOCP4 IOCP3 IOCP2 IOCP1 IOCP0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 IOCP<7:0>: Interrupt-on-Change Positive Edge Enable bits
1 = Interrupt-on-change is enabled on the pin for a rising edge; associated status bit and interrupt flag
will be set upon detecting an edge
0 = Interrupt-on-change is disabled for the associated pin
REGISTER 10-24: IOCN: INTERRUPT-ON-CHANGE NEGATIVE EDGE REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
IOCN7 IOCN6 IOCN5 IOCN4 IOCN3 IOCN2 IOCN1 IOCN0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 IOCN<7:0>: Interrupt-on-Change Negative Edge Enable bits
1 = Interrupt-on-change is enabled on the pin for a falling edge; associated status bit and interrupt flag
will be set upon detecting an edge
0 = Interrupt-on-change is disabled for the associated pin
REGISTER 10-25: IOCF: INTERRUPT-ON-CHANGE FLAG REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
IOCF7 IOCF6 IOCF5 IOCF4 IOCF3 IOCF2 IOCF1 IOCF0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 IOCF<7:0>: Interrupt-on-Change Flag bits
1 = An enabled change was detected on the associated pin; this is set when IOCP<x> = 1 and a positive
edge was detected on the input pin or when IOCN<x> = 1 and a negative edge was detected on the
input pin (clear in software to clear the IOCIF bit)
0 = No change was detected or the user cleared the detected change
2012 Microchip Technology Inc. DS30575A-page 195
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10.12 Context Saving During Interrupts
During interrupts, the return PC address is saved on
the stack. Additionally, the WREG, STATUS and BSR
registers are saved on the Fast Return Stack.
If a fast return from interrupt is not used (see
Section 6.3 “Data Memory Organization”), the user
may need to save the WREG, STATUS and BSR regis-
ters on entry to the Interrupt Service Routine (ISR).
Depending on the user’s application, other registers
also may need to be saved.
Example 10-1 saves and restores the WREG, STATUS
and BSR registers during an Interrupt Service Routine.
EXAMPLE 10-1: SAVING STATUS, WREG AND BSR REGISTERS IN RAM
MOVWF W_TEMP ; W_TEMP is in virtual bank
MOVFF STATUS, STATUS_TEMP ; STATUS_TEMP located anywhere
MOVFF BSR, BSR_TEMP ; BSR_TMEP located anywhere
;
; USER ISR CODE
;
MOVFF BSR_TEMP, BSR ; Restore BSR
MOVF W_TEMP, W ; Restore WREG
MOVFF STATUS_TEMP, STATUS ; Restore STATUS
PIC18F97J94 FAMILY
DS30575A-page 196 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 197
PIC18F97J94 FAMILY
11.0 I/O PORTS
Depending on the device selected and features
enabled, there are up to eleven ports available. Some
pins of the I/O ports are multiplexed with an alternate
function from the peripheral features on the device. In
general, when a peripheral is enabled, that pin may not
be used as a general purpose I/O pin.
Each port has three memory mapped registers for its
operation:
• TRIS register (Data Direction register)
• PORT register (reads the levels on the pins of the
device)
• LAT register (Output Latch register)
Reading the PORT register reads the current status of
the pins, whereas writing to the PORT register, writes
to the Output Latch (LAT) register.
Setting a TRIS bit (= 1) makes the corresponding
PORT pin an input (putting the corresponding output
driver in a High-Impedance mode). Clearing a TRIS bit
(= 0) makes the corresponding port pin an output (i.e.,
driving the contents of the corresponding LAT bit on the
selected pin).
The Output Latch (LAT register) is useful for
read-modify-write operations on the value that the I/O
pins are driving. Read-modify-write operations on the
LAT register read and write the latched output value for
the PORT register.
A simplified model of a generic I/O port, without the
interfaces to other peripherals, is shown in Figure 11-1.
FIGURE 11-1: GENERIC I/O PORT
OPERATION
11.1 I/O Port Pin Capabilities
When developing an application, the capabilities of the
port pins must be considered. All of the digital ports are
3.6V input tolerant.
11.1.1 OUTPUT PIN DRIVE
When used as digital I/O, the output pin drive strengths
vary, according to the pins’ grouping, to meet the needs
for a variety of applications. In general, there are two
classes of output pins in terms of drive capability:
• Outputs designed to drive higher current loads,
such as LEDs:
-PORTB
-PORTC
• Outputs with lower drive levels, but capable of
driving normal digital circuit loads with a high input
impedance. Able to drive LEDs, but only those
with smaller current requirements:
- PORTA - PORTD
- PORTE - PORTF
-PORTG - PORTH
(1)
-PORTJ
(1) -PORTK
(2)
-PORTL
(2)
11.1.2 PULL-UP CONFIGURATION
Nine of the I/O ports (all ports except PORTA and
PORTC) implement configurable weak pull-ups on all
pins. These are internal pull-ups that allow floating
digital input signals to be pulled to a consistent level
without the use of external resistors.
Pull-ups for PORTB are enabled by clearing the RBPU
bit (INTCON2<7>). PORTB pull-ups are individually
selectable through the WPUB register.
Pull-ups for PORTD, PORTE, PORTF, PORTG,
PORTH, PORTJ, PORTK and PORTL are enabled
through their corresponding enable bits in the PADCFG
register, but are not pin-selectable.
Data
Bus
WR LAT
WR TRIS
RD PORT
Data Latch
TRIS Latch
RD TRIS
Input
Buffer
I/O Pin
QD
CKx
QD
CKx
QD
EN
RD LAT
or PORT
Note 1: These ports are not available on 80-pin
devices.
2: These ports are not available on 80-pin or
100-pin devices.
PIC18F97J94 FAMILY
DS30575A-page 198 2012 Microchip Technology Inc.
REGISTER 11-1: PADCFG1: PAD CONFIGURATION REGISTER 1(1)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
RDPU REPU RFPU RGPU RHPU RJPU RKPU RLPU
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 RDPU: PORTD Pull-up Enable bit
1 = PORTD pull-ups are enabled for any input pad
0 = All PORTD pull-ups are disabled
bit 6 REPU: PORTE Pull-up Enable bit
1 = PORTE pull-ups are enabled for any input pad
0 = All PORTE pull-ups are disabled
bit 5 RFPU: PORTF Pull-up Enable bit
1 = PORTF pull-ups are enabled for any input pad
0 = All PORTF pull-ups are disabled
bit 4 RGPU: PORTG Pull-up Enable bit
1 = PORTG pull-ups are enabled for any input pad
0 = All PORTG pull-ups are disabled
bit 3 RHPU: PORTH Pull-up Enable bit
1 = PORTH pull-ups are enabled for any input pad
0 = All PORTH pull-ups are disabled
bit 2 RJPU: PORTJ Pull-up Enable bit
1 = PORTJ pull-ups are enabled for any input pad
0 = All PORTJ pull-ups are disabled
bit 1 RKPU: PORTK Pull-up Enable bit
1 = PORTK pull-ups are enabled for any input pad
0 = All PORTK pull-ups are disabled
bit 0 RLPU: PORTL Pull-up Enable bit
1 = PORTL pull-ups are enabled for any input pad
0 = All PORTL pull-ups are disabled
Note 1: If a particular PORT is not available on a package, the corresponding RnPU register bit will be
unimplemented and read back as ‘0’.
2012 Microchip Technology Inc. DS30575A-page 199
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11.1.3 OPEN-DRAIN OUTPUTS
The output pins for several peripherals are also
equipped with a configurable, open-drain output option.
This allows the peripherals to communicate with
external digital logic, operating at a higher voltage
level, without the use of level translators.
The open-drain option is implemented on the
EUSARTs, the MSSPx modules (in SPI mode) and the
CCP modules. These modules are assigned to an I/O
pin using the PPS (Peripheral Pin Select) feature. The
open-drain option is enabled by setting the open-drain
control bits in the ODCON1 and ODCON2 registers.
When the open-drain option is required, the output pin
must also be tied through an external pull-up resistor,
provided by the user, to a higher voltage level, up to 5V
(Figure 11-2). When a digital logic high signal is output,
it is pulled up to the higher voltage level.
FIGURE 11-2: USING THE OPEN-DRAIN
OUTPUT (USART SHOWN
AS EXAMPLE)
TXX
+5V
3.3V
(at logic ‘1’)
3.3V
VDD 5V
PIC18F97J94
REGISTER 11-2: ODCON1: PERIPHERAL OPEN-DRAIN CONTROL REGISTER 1
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ECCP2OD ECCP1OD USART4OD USART3OD USART2OD USART1OD SSP2OD SSP1OD
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ECCP2OD: ECCP2 Open Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 6 ECCP1OD: ECCP1 Open Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 5 USART4OD: EUSART4 Open Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 4 USART3OD: EUSART3 Open Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 3 USART2OD: EUSART2 Open Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 2 USART1OD: EUSART1 Open Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 1 SSP2OD: Open Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 0 SSP1OD: SPI1 Open Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
PIC18F97J94 FAMILY
DS30575A-page 200 2012 Microchip Technology Inc.
11.1.4 ANALOG AND DIGITAL PORTS
Many of the ports multiplex analog and digital function-
ality, providing a lot of flexibility for hardware designers.
PIC18F97J94 family devices can make any analog pin
analog or digital, depending on an application’s needs.
The ports’ analog/digital functionality is controlled by
the registers: ANCON1, ANCON2 and ANCON3.
Setting these registers makes the corresponding pins
analog and clearing the registers makes the ports
digital. For details on these registers, see Section 22.0
“12-Bit A/D Converter with Threshold Scan”
REGISTER 11-3: ODCON2: PERIPHERAL OPEN-DRAIN CONTROL REGISTER 2
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CCP10OD CCP9OD CCP8OD CCP7OD CCP6OD CCP5OD CCP4OD ECCP3OD
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CCP10OD: CCP10 Open-Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 6 CCP9OD: CCP9 Open-Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 5 CCP8OD: CCP8 Open-Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 4 CCP7OD: CCP7 Open-Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 3 CCP6OD: CCP6 Open-Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 2 CCP5OD: CCP5 Open-Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 1 CCP4OD: CCP4 Open-Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
bit 0 ECCP3OD: ECCP3 Open-Drain Output Enable bit
1 = Open-drain capability is enabled
0 = Open-drain capability is disabled
2012 Microchip Technology Inc. DS30575A-page 201
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11.2 PORTA, LATA and TRISA
Registers
PORTA is an 8-bit wide, bidirectional port. The corre-
sponding Data Direction and Output Latch registers are
TRISA and LATA.
All PORTA pins have Schmitt Trigger input levels and
full CMOS output drivers.
RA<5:0> are multiplexed with analog inputs for the A/D
Converter.
The operation of the analog inputs as A/D Converter
inputs is selected by clearing or setting the ANSELx
control bits in the ANCON1 register. The corresponding
TRISA bits control the direction of these pins, even
when they are being used as analog inputs. The user
must ensure the bits in the TRISA register are
maintained set when using them as analog inputs.
OSC2/CLKO/RA6 and OSC1/CLKI/RA7 normally
serve as the external circuit connections for the Exter-
nal (Primary) Oscillator circuit (HS Oscillator modes),
or the external clock input and output (EC Oscillator
modes). In these cases, RA6 and RA7 are not available
as digital I/O, and their corresponding TRIS and LAT
bits are read as ‘0’. When the device is configured to
use either the FRC or LPRC Internal Oscillators as the
default oscillator mode, RA6 and RA7 are automatically
configured as digital I/O; the oscillator and clock
in/clock out functions are disabled.
EXAMPLE 11-1: INITIALIZING PORTA
Note: RA<5:0> are configured as analog inputs
on any Reset and are read as ‘0’.
CLRF PORTA ; Initialize PORTA by
; clearing output latches
CLRF LATA ; Alternate method to
; clear output data latches
BANKSEL ANCON1 ; Select bank with ANCON1 register
MOVLW 00h ; Configure A/D
MOVWF ANCON1 ; for digital inputs
BANKSEL TRISA ; Select bank with TRISA register
MOVLW 0BFh ; Value used to initialize
; data direction
MOVWF TRISA ; Set RA<7, 5:0> as inputs,
; RA<6> as output
TABLE 11-1: PORTA FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O
Type Description
RA0/AN0/AN1-/RP0/
SEG19
RA0 0O DIG LATA<0> data output; not affected by analog input.
1I ST PORTA<0> data input; disabled when analog input is enabled.
AN0 1I ANA A/D Input Channel 0. Default input configuration on POR; does not
affect digital output.
AN1- 1I ANA Quasi-differential A/D negative input channel.
RP0 xx DIG Reconfigurable Pin 0 for PPS-Lite; TRIS must be set to match
input/output of the module.
SEG19 0O ANA LCD Segment 19 output; disables all other pin functions.
RA1/AN1/RP1/SEG18 RA1 0O DIG LATA<1> data output; not affected by analog input.
1I ST PORTA<1> data input; disabled when analog input is enabled.
AN1 1I ANA A/D Input Channel 1. Default input configuration on POR; does not
affect digital output.
RP1 xx DIG Reconfigurable Pin 1 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG18 0O ANA LCD Segment 18 output; disables all other pin functions.
RA2/AN2/VREF-/RP2/
SEG21
RA2 0O DIG LATA<2> data output; not affected by analog input.
1I ST PORTA<2> data input; disabled when analog input enabled.
AN2 1I ANA A/D Input Channel 2. Default input configuration on POR; does not
affect digital output.
VREF-1I ANA A/D and Comparator Low Reference Voltage input.
RP2 xx DIG Reconfigurable Pin 2 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG21 0O ANA LCD Segment 21 output; disables all other pin functions.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
PIC18F97J94 FAMILY
DS30575A-page 202 2012 Microchip Technology Inc.
RA3/AN3/VREF+/RP3 RA3 0O DIG LATA<3> data output; not affected by analog input.
1I ST PORTA<3> data input; disabled when analog input is enabled.
AN3 1I ANA A/D Input Channel 3. Default input configuration on POR; does not
affect digital output.
VREF+1I ANA A/D and Comparator High Reference Voltage input.
RP3 xx DIG Reconfigurable Pin 3 for PPS-Lite; TRIS must be set to match
input/output of module.
RA4/AN6/RP4/SEG14 RA4 0O DIG LATA<4> data output; not affected by analog input.
1I ST PORTA<4> data input; disabled when analog input is enabled.
AN6 1I ANA A/D Input Channel 6. Default input configuration on POR; does not
affect digital output.
RP4 xx DIG Reconfigurable Pin 4 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG14 0O ANA LCD Segment 14 output; disables all other pin functions.
RA5/AN4/RP5/LVDIN/
C1INA/C2INA/C3INA/
SEG15
RA5 0O DIG LATA<5> data output; not affected by analog input.
1I ST PORTA<5> data input; disabled when analog input is enabled.
AN4 1I ANA A/D Input Channel 4. Default input configuration on POR; does not
affect digital output.
RP5 xx DIG Reconfigurable Pin 5 for PPS-Lite; TRIS must be set to match
input/output of module.
LVDIN 1I ANA High/Low-Voltage Detect (HLVD) external trip point input.
C1INA 1I ANA Comparator 1 Input A.
C2INA 1I ANA Comparator 2 Input A.
C3INA 1I ANA Comparator 3 Input A.
SEG15 0O ANA LCD Segment 15 output; disables all other pin functions.
RA6/RP6/CLKO/OSC2 RA6 0O DIG LATA<6> data output; disabled when OSC2 Configuration bit is set.
1I ST PORTA<6> data input; disabled when OSC2 Configuration bit is set.
RP6 xx DIG Reconfigurable Pin 6 for PPS-Lite; TRIS must be set to match
input/output of module.
CLKO xO DIG System cycle clock output (FOSC/4, EC and Internal Oscillator
modes).
OSC2 xO ANA Main oscillator feedback output connection (HS, MS and LP
modes).
RA7/RP10/CLKI/OSC1 RA7 0O DIG LATA<7> data output; disabled when OSC2 Configuration bit is set.
1I ST PORTA<7> data input; disabled when OSC2 Configuration bit is set.
RP10 xx DIG Reconfigurable Pin 10 for PPS-Lite; TRIS must be set to match
input/output of module.
CLKI xO DIG Main external clock source input (EC modes).
OSC1 xO ANA Main oscillator input connection (HS, MS and LP modes).
TABLE 11-1: PORTA FUNCTIONS (CONTINUED)
Pin Name Function TRIS
Setting I/O I/O
Type Description
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
2012 Microchip Technology Inc. DS30575A-page 203
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11.3 PORTB, LATB and TRISB
Registers
PORTB is an eight-bit wide, bidirectional port. The
corresponding Data Direction and Output Latch registers
are TRISB and LATB. All pins on PORTB are digital only.
EXAMPLE 11-2: INITIALIZING PORTB
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is
performed by clearing bit, RBPU (INTCON2<7>), and
setting the associated WPUB bit. The weak pull-up is
automatically turned off when the port pin is configured
as an output. The pull-ups are disabled on a Power-on
Reset.
The RB<3:2> pins are multiplexed as CTMU edge
inputs.
CLRF PORTB ; Initialize PORTB by
; clearing output
; data latches
CLRF LATB ; Alternate method
; to clear output
; data latches
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISB ; Set RB<3:0> as inputs
; RB<5:4> as outputs
; RB<7:6> as inputs
TABLE 11-2: PORTB FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O
Type Description
RB0/INT0/CTED13/
RP8/VLCAP1
RB0 0O DIG LATB<0> data output.
1I ST PORTB<0> data input.
INT0 1I ST External Interrupt 0 input.
CTED13 1I ST CTMU Edge 13 input.
RP8 xx DIG Reconfigurable Pin 8 for PPS-Lite; TRIS must be set to match
input/output of module.
VLCAP1xx ANA External capacitor connection for LCD module.
RB1/RP9/VLCAP2RB10O DIG LATB<1> data output.
1I ST PORTB<1> data input.
RP9 xx DIG Reconfigurable Pin 9 for PPS-Lite; TRIS must be set to match
input/output of module.
VLCAP2xx ANA External capacitor connection for LCD module.
RB2/CTED1/RP14/
SEG9
RB2 0O DIG LATB<2> data output.
1I ST PORTB<2> data input.
CTED1 1I ST CTMU Edge 1 input.
RP14 xx DIG Reconfigurable Pin 14 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG9 0O ANA LCD Segment 9 output; disables all other pin functions.
RB3/CTED2/RP7/
SEG10
RB3 0O DIG LATB<3> data output.
1I ST PORTB<3> data input.
CTED2 1I ST CTMU Edge 2 input.
RP7 xx DIG Reconfigurable Pin 7 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG10 0O ANA LCD Segment 10 output; disables all other pin functions.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
PIC18F97J94 FAMILY
DS30575A-page 204 2012 Microchip Technology Inc.
RB4/CTED3/RP12/
SEG11
RB4 0O DIG LATB<4> data output.
1I ST PORTB<4> data input.
CTED3 1I ST CTMU Edge 3 input.
RP12 xx DIG Reconfigurable Pin 12 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG11 0O ANA LCD Segment 11 output; disables all other pin functions.
RB5/CTED4/RP13/
SEG8
RB5 0O DIG LATB<5> data output.
1I ST PORTB<5> data input.
CTED4 1I ST CTMU Edge 4 input.
RP13 xx DIG Reconfigurable Pin 13 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG8 0O ANA LCD Segment 8 output; disables all other pin functions.
RB6/CTED5/PGC RB6 0O DIG LATB<6> data output.
1I ST PORTB<6> data input.
CTED5 1I ST CTMU Edge 5 input.
PGC xI ST Serial execution (ICSP™) clock input for ICSP and ICD
operations.
RB7/CTED6/PGD RB7 0O DIG LATB<7> data output.
1I ST PORTB<7> data input.
CTED6 1I ST CTMU Edge 6 input.
PGD xI/O ST/DIG Serial execution (ICSP™) data input/output for ICSP and ICD
operations.
TABLE 11-2: PORTB FUNCTIONS (CONTINUED)
Pin Name Function TRIS
Setting I/O I/O
Type Description
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
2012 Microchip Technology Inc. DS30575A-page 205
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11.4 PORTC, LATC and TRISC
Registers
PORTC is an eight-bit wide, bidirectional port. The
corresponding Data Direction and Output Latch registers
are TRISC and LATC. Only PORTC pins, RC2 through
RC7, are digital only pins. The pins have Schmitt Trigger
input buffers.
When enabling peripheral functions, use care in defin-
ing TRIS bits for each PORTC pin. Some peripherals
can override the TRIS bit to make a pin an output or
input. Consult the corresponding peripheral section for
the correct TRIS bit settings.
The contents of the TRISC register are affected by
peripheral overrides. Reading TRISC always returns
the current contents, even though a peripheral device
may be overriding one or more of the pins.
EXAMPLE 11-3: INITIALIZING PORTC
Note: These pins are configured as digital inputs
on any device Reset.
CLRF PORTC ; Initialize PORTC by
; clearing output
; data latches
CLRF LATC ; Alternate method
; to clear output
; data latches
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISC ; Set RC<3:0> as inputs
; RC<5:4> as outputs
; RC<7:6> as inputs
TABLE 11-3: PORTC FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O
Type Description
RC0/
PWRLCLK/
SCLKI/SOSCO
RC0 0O DIG LATC<0> data output.
1I ST PORTC<0> data input.
PWRLCLK 1I ST Optional RTCC input from power line clock (50 or 60 Hz).
SCLKI xI ST Digital SOSC input.
SOSCO xO ANA Secondary Oscillator (SOSC) feedback output connection.
RC1/SOSCI RC1 0O DIG LATC<1> data output.
1I ST PORTC<1> data input.
SOSCI xI ANA Secondary Oscillator (SOSC) input connection.
RC2/CTED7/
RP11/AN9/
SEG13
RC2 0O DIG LATC<2> data output; not affected by analog input.
1I ST PORTC<2> data input; disabled when analog input is enabled.
CTED7 1I ST CTMU Edge 7 input.
RP11 xx DIG Reconfigurable Pin 11 for PPS-Lite; TRIS must be set to match input/output of
module.
AN9 1I ANA A/D Input Channel 9. Default input configuration on POR; does not affect digital
output.
SEG13 0O ANA LCD Segment 13 output; disables all other pin functions.
RC3/CTED8/
RP15/SCL1/
SEG17
RC3 0O DIG LATC<3> data output.
1I ST PORTC<3> data input.
CTED8 1I ST CTMU Edge 8 input.
RP15 xx DIG Reconfigurable Pin 15 for PPS-Lite; TRIS must be set to match input/output of
module.
SCL1 xI/O I2C Synchronous serial clock input/output for I2C™ mode.
SEG17 0O ANA LCD Segment 17 output; disables all other pin functions
RC4/CTED9/
RP17/SDA1/
SEG16
RC4 0O DIG LATC<4> data output.
1I ST PORTC<4> data input.
CTED9 1I ST CTMU Edge 9 input.
RP17 xx DIG Reconfigurable Pin 17 for PPS-Lite; TRIS must be set to match input/output of
module.
SDA1 xI/O I2C I2C™ mode data I/O
SEG16 0O ANA LCD Segment 16 output; disables all other pin functions.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input, I2C = I2C™/SMBus,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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DS30575A-page 206 2012 Microchip Technology Inc.
RC5/CTED10/
RP16/SEG12
RC5 0O DIG LATC<5> data output.
1I ST PORTC<5> data input.
CTED10 1I ST CTMU Edge 10 input.
RP16 xx DIG Reconfigurable Pin 16 for PPS-Lite; TRIS must be set to match input/output of
module.
SEG12 0O ANA LCD Segment 12 output; disables all other pin functions.
RC6/CTED11/
UOE/RP18/
SEG27
RC6 0O DIG LATC<6> data output.
1I ST PORTC<6> data input.
CTED11 1I ST CTMU Edge 11 input.
UOE 0O DIG USB Output Enable control (for external transceiver).
RP18 xx DIG Reconfigurable Pin 18 for PPS-Lite; TRIS must be set to match input/output of
module.
SEG27 0O ANA LCD Segment 27 output; disables all other pin functions.
RC7/CTED12/
RP19/SEG22
RC7 0O DIG LATC<7> data output.
1I ST PORTC<7> data input.
CTED12 1I ST CTMU Edge 12 input.
RP19 xx DIG Reconfigurable Pin 19 for PPS-Lite; TRIS must be set to match input/output of
module.
SEG22 0O ANA LCD Segment 22 output; disables all other pin functions.
TABLE 11-3: PORTC FUNCTIONS (CONTINUED)
Pin Name Function TRIS
Setting I/O I/O
Type Description
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input, I2C = I2C™/SMBus,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
2012 Microchip Technology Inc. DS30575A-page 207
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11.5 PORTD, LATD and
TRISD Registers
PORTD is an 8-bit wide, bidirectional port. The
corresponding Data Direction and Output Latch registers
are TRISD and LATD.
All pins on PORTD are implemented with Schmitt
Trigger input buffers. Each pin is individually
configurable as an input or output.
Each of the PORTD pins has a weak internal pull-up. A
single control bit can turn off all the pull-ups. This is
performed by setting bit, RDPU (PADCFG<7>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on all device Resets.
On 80-pin and 100-pin devices, PORTD is multiplexed
with the system bus as part of the external memory
interface. I/O port and other functions are only available
when the interface is disabled by setting the EBDIS bit
(MEMCON<7>). When the interface is enabled,
PORTD is the low-order byte of the multiplexed
Address/Data bus (AD<7:0>). The TRISD bits are also
overridden.
PORTD can also be configured as an 8-bit wide micro-
processor port (Parallel Slave Port) by setting control
bit, PSPMODE (PSPCON<4>). In this mode, the input
buffers are TTL. For additional information, see
Section 11.13 “Parallel Slave Port”.
PORTD also has I2C functionality on RD5 and RD6.
EXAMPLE 11-4: INITIALIZING PORTD
Note: These pins are configured as digital inputs
on any device Reset.
CLRF PORTD ; Initialize PORTD by
; clearing output
; data latches
CLRF LATD ; Alternate method
; to clear output
; data latches
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISD ; Set RD<3:0> as inputs
; RD<5:4> as outputs
; RD<7:6> as inputs
TABLE 11-4: PORTD FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O
Type Description
RD0/PSP0/
RP20/SEG0/AD0
RD0 0O DIG LATD<0> data output.
1I ST PORTD<0> data input.
PSP0 xI/O ST/DIG Parallel Slave Port Data Bus Bit 0.
RP20 xx DIG Reconfigurable Pin 20 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG0 0O ANA LCD Segment 0 output; disables all other pin functions.
AD0 xI/O ST/DIG External Memory Bus Address Line 0.
RD1/PSP1/
RP21/SEG1/AD1
RD1 0O DIG LATD<1> data output.
1I ST PORTD<1> data input.
PSP1 xI/O ST/DIG Parallel Slave Port Data Bus Bit 1.
RP21 xx DIG Reconfigurable Pin 21 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG1 0O ANA LCD Segment 1 output; disables all other pin functions.
AD1 xI/O ST/DIG External Memory Bus Address Line 1.
RD2/PSP2/
RP22/SEG2/AD2
RD2 0O DIG LATD<2> data output.
1I ST PORTD<2> data input.
PSP2 xI/O ST/DIG Parallel Slave Port Data Bus Bit 2.
RP22 xx DIG Reconfigurable Pin 22 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG2 0O ANA LCD Segment 2 output; disables all other pin functions.
AD2 xI/O ST/DIG External Memory Bus Address Line 2.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
I2C = I2C™/SMBus, x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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DS30575A-page 208 2012 Microchip Technology Inc.
RD3/PSP3/
RP23/SEG3/AD3
RD3 0O DIG LATD<3> data output.
1I ST PORTD<3> data input.
PSP3 xI/O ST/DIG Parallel Slave Port Data Bus Bit 3.
RP23 xx DIG Reconfigurable Pin 23 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG3 0O ANA LCD Segment 3 output; disables all other pin functions.
AD3 xI/O ST/DIG External Memory Bus Address Line 3.
RD4/PSP4/
RP24/SEG4/AD4
RD4 0O DIG LATD<4> data output.
1I ST PORTD<4> data input.
PSP4 xI/O ST/DIG Parallel Slave Port Data Bus Bit 4.
RP24 xxDIG Reconfigurable Pin 24 for PPS-Lite; TRIS must be set to match
input/output of module.
SEG4 0O ANA LCD Segment 4 output; disables all other pin functions.
AD4 xI/O ST/DIG External Memory Bus Address Line 4.
RD5/PSP5/
RP25/SDA2/
SEG5/AD5
RD5 0O DIG LATD<5> data output.
1I ST PORTD<5> data input.
PSP5 xI/O ST/DIG Parallel Slave Port Data Bus Bit 5.
RP25 xx DIG Reconfigurable Pin 25 for PPS-Lite; TRIS must be set to match
input/output of module.
SDA2 xI/O ST/DIG I2C mode data I/O.
SEG5 0O ANA LCD Segment 5 output; disables all other pin functions.
AD5 xI/O ST/DIG External Memory Bus Address Line 5.
RD6/PSP6/
RP26/SCL2/
SEG6/AD6
RD6 0O DIG LATD<6> data output.
1I ST PORTD<6> data input.
PSP6 xI/O ST/DIG Parallel Slave Port Data Bus Bit 6.
RP26 xx DIG Reconfigurable Pin 26 for PPS-Lite; TRIS must be set to match
input/output of module.
SCL2 xI/O I2C Synchronous serial clock input/output for I2C™ mode.
SEG6 0O ANA LCD Segment 6 output; disables all other pin functions.
AD6 xI/O ST/DIG External Memory Bus Address Line 6.
RD7/PSP7/
RP27/REFO2/
SEG7/AD7
RD7 0O DIG LATD<7> data output.
1I ST PORTD<7> data input.
PSP7 xI/O ST/DIG Parallel Slave Port Data Bus Bit 7.
RP27 xx DIG Reconfigurable Pin 27 for PPS-Lite; TRIS must be set to match
input/output of module.
REFO2 0O DIG Reference Clock 2 output.
SEG7 0O ANA LCD Segment 7 output; disables all other pin functions.
AD7 xI/O ST/DIG External Memory Bus Address Line 7.
TABLE 11-4: PORTD FUNCTIONS (CONTINUED)
Pin Name Function TRIS
Setting I/O I/O
Type Description
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
I2C = I2C™/SMBus, x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
2012 Microchip Technology Inc. DS30575A-page 209
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11.6 PORTE, LATE and
TRISE Registers
PORTE is an eight-bit wide, bidirectional port. The
corresponding Data Direction and Output Latch registers
are TRISE and LATE.
All pins on PORTE are implemented with Schmitt
Trigger input buffers. Each pin is individually
configurable as an input or output.
Each of the PORTE pins has a weak internal pull-up. A
single control bit can turn off all the pull-ups. This is
performed by setting bit, REPU (PADCFG<6>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on any device Reset.
For devices operating in Microcontroller mode, the RE7
pin can be configured as the alternate peripheral pin for
the ECCP2 module and Enhanced PWM Output 2A.
PORTE is also multiplexed with the Parallel Slave Port
address lines. RE2, RE1 and RE0 are multiplexed with
the control signals, CS, WR and RD.
RE3 can also be configured as the Reference Clock
Output (REFO) from the system clock. For further
details, see Section 3.4 “Reference Clock Output
Control Module”.
EXAMPLE 11-5: INITIALIZING PORTE
Note: These pins are configured as digital inputs
on any device Reset.
CLRF PORTE ; Initialize PORTE by
; clearing output
; data latches
CLRF LATE ; Alternate method
; to clear output
; data latches
MOVLW 03h ; Value used to
; initialize data
; direction
MOVWF TRISE ; Set RE<1:0> as inputs
; RE<7:2> as outputs
TABLE 11-5: PORTE FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O
Type Description
RE0//RD/RP28/
LCDBIAS1/AD8
RE0 0O DIG LATE<0> data output.
1I ST PORTE<0> data input.
RD 1I ST Parallel Slave Port (PSP) Read (RD) signal.
RP28 xx DIG Reconfigurable Pin 28 for PPS-Lite; TRIS must be set to match
input/output of module.
LCDBIAS1 xI ANA LCD Module Bias Voltage Input 1.
AD8 xI/O ST/DIG External Memory Bus Address Line 8.
RE1//WR/RP29/
LCDBIAS2/AD9
RE1 0O DIG LATE<1> data output.
1I ST PORTE<1> data input.
WR 1I ST Parallel Slave Port (PSP) Write (WR) signal.
RP29 xx DIG Reconfigurable Pin 29 for PPS-Lite; TRIS must be set to match
input/output of module.
LCDBIAS2 xI ANA LCD Module Bias Voltage Input 2.
AD9 xI/O ST/DIG External Memory Bus Address Line 9.
RE2/CS/RP30/
LCDBIAS3/AD10
RE2 0O DIG LATE<2> data output.
1I ST PORTE<2> data input.
CS 1I ST Parallel Slave Port (PSP) Chip Select (CS) signal.
RP30 xx DIG Reconfigurable Pin 30 for PPS-Lite; TRIS must be set to match
input/output of module.
LCDBIAS3 xI ANA LCD Module Bias Voltage Input 3.
AD10 xI/O ST/DIG External Memory Bus Address Line 10.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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RE3/REFO1/
RP33/COM0/
AD11
RE3 0O DIG LATE<3> data output.
1I ST PORTE<3> data input.
REFO1 0O DIG Reference Clock Output 1.
RP33 xx DIG Reconfigurable Pin 33 for PPS-Lite; TRIS must be set to match
input/output of module.
COM0 xO ANA LCD Common 0 output; disables all other outputs.
AD11 xI/O ST/DIG External Memory Bus Address Line 11.
RE4/RP32/
COM1/AD12
RE4 0O DIG LATE<4> data output.
1I ST PORTE<4> data input.
RP32 xx DIG Reconfigurable Pin 32 for PPS-Lite; TRIS must be set to match
input/output of module.
COM1 xO ANA LCD Common 1 output; disables all other outputs.
AD12 xI/O ST/DIG External Memory Bus Address Line 12.
RE5/RP37/
COM2/AD13
RE5 0O DIG LATE<5> data output.
1I ST PORTE<5> data input.
RP37 xx DIG Reconfigurable Pin 37 for PPS-Lite; TRIS must be set to match
input/output of module.
COM2 xO ANA LCD Common 2 output; disables all other outputs.
AD13 xI/O ST/DIG External Memory Bus Address Line 13.
RE6/RP34/
COM3/AD14
RE6 0O DIG LATE<6> data output.
1I ST PORTE<6> data input.
RP34 xx DIG Reconfigurable Pin 34 for PPS-Lite; TRIS must be set to match
input/output of module.
COM3 xO ANA LCD Common 3 output; disables all other outputs.
AD14 xI/O ST/DIG External Memory Bus Address Line 14.
RE7/RP31/
LCDBIAS0/
AD15
RE7 0O DIG LATE<7> data output.
1I ST PORTE<7> data input.
RP31 xx DIG Reconfigurable Pin 31 for PPS-Lite; TRIS must be set to match
input/output of module.
LCDBIAS0 xI ANA LCD Module Bias Voltage Input 0.
AD15 xI/O ST/DIG External Memory Bus Address Line 15.
TABLE 11-5: PORTE FUNCTIONS (CONTINUED)
Pin Name Function TRIS
Setting I/O I/O
Type Description
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
2012 Microchip Technology Inc. DS30575A-page 211
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11.7 PORTF, LATF and TRISF Registers
PORTF is a 6-bit wide, bidirectional port. The
corresponding Data Direction and Output Latch registers
are TRISF and LATF. All pins on PORTF are
implemented with Schmitt Trigger input buffers. Each pin
is individually configurable as an input or output.
Pins, RF2 through RF6, may be used as comparator
inputs or outputs by setting the appropriate bits in the
CMCON register. To use RF<7:2> as digital inputs, it is
also necessary to turn off the comparators.
EXAMPLE 11-6: INITIALIZING PORTF
Note 1: On device Resets, pins, RF<7:2>, are
configured as analog inputs and are read
as ‘0’.
2: To configure PORTF as a digital I/O, turn
off the comparators and clear ANCON1
and ANCON2 to digital.
CLRF PORTF ; Initialize PORTF by
; clearing output
; data latches
CLRF LATF ; Alternate method
; to clear output
; data latches
BANKSEL ANCON1 ; Select bank with ANCON1 register
MOVLW 1Fh ; Make AN6, AN7 and AN5 digital
MOVWF ANCON1 ;
MOVLW 0Fh ; Make AN8, AN9, AN10 and AN11
digital
MOVWF ANCON ; Set PORTF as digital I/O
BANKSEL TRISF ; Select bank with TRISF register
MOVLW 0CEh ; Value used to
; initialize data
; direction
MOVWF TRISF ; Set RF3:RF2 as inputs
; RF5:RF4 as outputs
; RF7:RF6 as inputs
TABLE 11-6: PORTF FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O
Type Description
RF0 — — — — PORTF<0> is not implemented.
RF1 — — — — PORTF<1> is not implemented.
RF2/RP36/C2INB/
CTMUI/SEG20/
AN7
RF2 0O DIG LATF<2> data output.
1I ST PORTF<2> data input.
RP36 xx DIG Reconfigurable Pin 36 for PPS-Lite; TRIS must be set to match
input/output of module.
C2INB 1I ANA Comparator 2 Input B.
CTMUI 1I ANA CTMU comparator input.
SEG20 0O ANA LCD Segment 20 output; disables all other pin functions.
AN7 1I ANA A/D Input Channel 7. Default input configuration on POR; does not
affect digital output.
RF3/RP41/D- RF3 0O DIG LATF<3> data output.
1I ST PORTF<3> data input.
RP41 xx DIG Reconfigurable Pin 41 for PPS-Lite; TRIS must be set to match
input/output of module.
D- xI XCVR USB bus minus line output.
xO XCVR USB bus minus line input.
RF4/RP45/D+ RF4 0O DIG LATF<4> data output.
1I ST PORTF<4> data input.
RP45 xx DIG Reconfigurable Pin 45 for PPS-Lite.
D+ xI XCVR USB bus plus line input.
xO XCVR USB bus plus line output.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
XCVR = USB Transceiver, x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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DS30575A-page 212 2012 Microchip Technology Inc.
RF5/RP35/C1INB/
AN10/CVREF/
SEG23
RF5 0O DIG LATF<5> data output.
1I ST PORTF<5> data input.
RP35 xx DIG Reconfigurable Pin 35 for PPS-Lite; TRIS must be set to match
input/output of module.
C1INB 1I ANA Comparator 1 Input B.
AN10 1I ANA A/D Input Channel 10. Default input configuration on POR; does not
affect digital output.
CVREF 0O ANA Comparator reference voltage output.
SEG23 0O ANA LCD Segment 23 output; disables all other pin functions.
RF6/RP40/C1INA/
AN11/SEG24
RF6 0O DIG LATF<6> data output.
1I ST PORTF<6> data input.
RP40 xx DIG Reconfigurable Pin 40 for PPS-Lite; TRIS must be set to match
input/output of module.
C1INA 1I ANA Comparator 1 Input A.
AN11 1I ANA A/D Input Channel 11. Default input configuration on POR; does not
affect digital output.
SEG24 0O ANA LCD Segment 24 output; disables all other pin functions.
RF7/RP38/AN5/
SEG25
RF7 0O DIG LATF<7> data output.
1I ST PORTF<7> data input.
RP38 xx DIG Reconfigurable Pin 38 for PPS-Lite; TRIS must be set to match
input/output of module.
AN5 1I ANA A/D Input Channel 5. Default input configuration on POR; does not
affect digital output.
SEG25 0O ANA LCD Segment 25 output; disables all other pin functions.
TABLE 11-6: PORTF FUNCTIONS (CONTINUED)
Pin Name Function TRIS
Setting I/O I/O
Type Description
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
XCVR = USB Transceiver, x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
2012 Microchip Technology Inc. DS30575A-page 213
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11.8 PORTG, LATG and TRISG
Registers
PORTG width varies depending on pin count. For
64- and 80-pin devices, PORTG is a 6-bit wide, bidirec-
tional port. For 100-pin devices, PORTG is an 8-bit wide
bidirectional port. The corresponding Data Direction and
Output Latch registers are TRISG and LATG.
PORTG is multiplexed with the EUSART, and CCP,
ECCP, Analog, Comparator, RTCC and Timer input
functions (Table 11-7). When operating as I/O, all
PORTG pins have Schmitt Trigger input buffers. The
open-drain functionality for the CCPx and EUSARTx
can be configured using ODCONx.
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTG pin. Some
peripherals override the TRIS bit to make a pin an
output, while other peripherals override the TRIS bit to
make a pin an input. The user should refer to the
corresponding peripheral section for the correct TRIS bit
settings. The pin override value is not loaded into the
TRIS register. This allows read-modify-write of the TRIS
register without concern due to peripheral overrides.
EXAMPLE 11-7: INITIALIZING PORTG
CLRF PORTG ; Initialize PORTG by
; clearing output
; data latches
BCF CM1CON, CON ; disable
; comparator 1
CLRF LATG ; Alternate method
; to clear output
; data latches
BANKSEL ANCON2 ; Select bank with ACON2 register
MOVLW 0F0h ; make AN16 to AN19
; digital
MOVWF ANCON2
BANKSEL TRISG ; Select bank with TRISG register
MOVLW 04h ; Value used to
; initialize data
; direction
MOVWF TRISG ; Set RG1:RG0 as
; outputs
; RG2 as input
; RG4:RG3 as inputs
TABLE 11-7: PORTG FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O
Type Description
RG0/RP46/AN8/
SEG28/COM4
RG0 0O DIG LATG<0> data output; not affected by analog input.
1I ST PORTG<0> data input; disabled when analog input is enabled.
RP46 xx DIG Reconfigurable Pin 46 for PPS-Lite; TRIS must be set to match
input/output of module.
AN8 1I ANA A/D Input Channel 8. Default input configuration on POR; does not
affect digital output.
SEG28 0O ANA LCD Segment 28 output; disables all other pin functions.
COM4 xO ANA LCD Common 4 output; disables all other outputs.
RG1/RP39/
AN19/SEG29/
COM5
RG1 0O DIG LATG<1> data output; not affected by analog input.
1I ST PORTG<1> data input; disabled when analog input is enabled.
RP39 xx DIG Reconfigurable Pin 39 for PPS-Lite; TRIS must be set to match
input/output of module.
AN19 1I ANA A/D Input Channel 19. Default input configuration on POR; does not
affect digital output.
SEG29 0O ANA LCD Segment 29 output; disables all other pin functions.
COM5 xO ANA LCD Common 5 output; disables all other outputs.
RG2/RP42/
C3INA/AN18/
SEG30/COM6
RG2 0O DIG LATG<2> data output; not affected by analog input.
1I ST PORTG<2> data input; disabled when analog input is enabled.
RP42 xx DIG Reconfigurable Pin 42 for PPS-Lite; TRIS must be set to match
input/output of module.
C3INA 1I ANA Comparator 3 Input A.
AN18 1I ANA A/D Input Channel 18. Default input configuration on POR; does not
affect digital output.
SEG30 0O ANA LCD Segment 30 output; disables all other pin functions.
COM6 xO ANA LCD Common 6 output; disables all other outputs.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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DS30575A-page 214 2012 Microchip Technology Inc.
RG3/RP43/
C3INB/AN17/
SEG31/COM7
RG3 0O DIG LATG<3> data output; not affected by analog input.
1I ST PORTG<3> data input; disabled when analog input is enabled.
RP43 xx DIG Reconfigurable Pin 43 for PPS-Lite; TRIS must be set to match
input/output of module.
C3INB 1I ANA Comparator 3 Input B.
AN17 1I ANA A/D Input Channel 17. Default input configuration on POR; does not
affect digital output.
SEG31 0O ANA LCD Segment 31 output; disables all other pin functions.
COM7 xO ANA LCD Common 7 output; disables all other outputs.
RG4/RTCC/
RP44/C3INC/
AN16/SEG26
RG4 0O DIG LATG<4> data output; not affected by analog input.
1I ST PORTG<4> data input; disabled when analog input is enabled.
RTCC xO DIG RTCC output.
RP44 xx DIG Reconfigurable Pin 44 for PPS-Lite; TRIS must be set to match
input/output of module.
C3INC 1I ANA Comparator 3 Input C.
AN16 1I ANA A/D Input Channel 16. Default input configuration on POR; does not
affect digital output.
SEG26 0O ANA LCD Segment 26 output; disables all other pin functions.
RG6 RG6 0O DIG LATG<6> data output.
1I ST PORTG<6> data input.
RG7 RG7 0O DIG LATG<7> data output.
1I ST PORTG<7> data input.
TABLE 11-7: PORTG FUNCTIONS (CONTINUED)
Pin Name Function TRIS
Setting I/O I/O
Type Description
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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11.9 PORTH, LATH and
TRISH Registers
PORTH is an 8-bit wide, bidirectional I/O port. The
corresponding Data Direction and Output Latch registers
are TRISH and LATH.
All pins on PORTH are implemented with Schmitt
Trigger input buffers. Each pin is individually
configurable as an input or output.
EXAMPLE 11-8: INITIALIZING PORTH
Note: PORTH is available only on 80-pin and
100-pin devices.
CLRF PORTH ; Initialize PORTH by
; clearing output
; data latches
CLRF LATH ; Alternate method
; to clear output
; data latches
BANKSEL ANCON2 ; Select bank with ANCON2 register
MOVLW 0Fh ; Configure PORTH as
MOVWF ANCON2 ; digital I/O
MOVLW 0Fh ; Configure PORTH as
MOVWF ANCON1 ; digital I/O
BANKSEL TRISH ; Select bank with TRISH register
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISH ; Set RH3:RH0 as inputs
; RH5:RH4 as outputs
; RH7:RH6 as inputs
TABLE 11-8: PORTH FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O Type Description
RH0/AN23/
SEG47/A16
RH0 0O DIG LATH<0> data output; not affected by analog input.
1I ST PORTH<0> data input.
AN23 1I ANA A/D Input Channel 23. Default input configuration on POR; does not
affect digital output.
SEG47 0O ANA LCD Segment 47 output; disables all other pin functions.
A16 xO DIG External Memory Bus Address<16> output.
RH1/AN22/
SEG46/A17
RH1 0O DIG LATH<1> data output; not affected by analog input.
1I ST PORTH<1> data input.
AN22 1I ANA A/D Input Channel 22. Default input configuration on POR; does not
affect digital output.
SEG46 0O ANA LCD Segment 46 output; disables all other pin functions.
A17 xO DIG External Memory Bus Address<17> output.
RH2/AN21/
SEG45/A18
RH2 0O DIG LATH<2> data output; not affected by analog input.
1I ST PORTH<2> data input.
AN21 1I ANA A/D Input Channel 21. Default input configuration on POR; does not
affect digital output.
SEG45 0O ANA LCD Segment 45 output; disables all other pin functions.
A18 xO DIG External Memory Bus Address<18> output.
RH3/AN20/
SEG44/A19
RH3 0O DIG LATH<3> data output; not affected by analog input.
1I ST PORTH<3> data input.
AN20 1I ANA A/D Input Channel 20. Default input configuration on POR; does not
affect digital output.
SEG44 0O ANA LCD Segment 44 output; disables all other pin functions.
A19 xO DIG External Memory Bus Address<19> output.
RH4/C2INC/
AN12/SEG40
RH4 0O DIG LATH<4> data output; not affected by analog input.
1I ST PORTH<4> data input; disabled when analog input is enabled.
C2INC 1I ANA Comparator 2 Input C.
AN12 1I ANA A/D Input Channel 12. Default input configuration on POR; does not
affect digital output.
SEG40 0O ANA LCD Segment 40 output; disables all other pin functions.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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RH5/C2IND/AN
13/SEG41
RH5 0O DIG LATH<5> data output; not affected by analog input.
1I ST PORTH<5> data input; disabled when analog input is enabled.
C2IND 1I ANA Comparator 2 Input D.
AN13 1I ANA A/D Input Channel 13. Default input configuration on POR; does not
affect digital output.
SEG41 0O ANA LCD Segment 41 output; disables all other pin functions.
RH6/C1INC/AN
14/SEG42
RH6 0O DIG LATH<6> data output; not affected by analog input.
1I ST PORTH<6> data input; disabled when analog input is enabled.
C1INC 1I ANA Comparator 1 Input C.
AN14 1I ANA A/D Input Channel 14. Default input configuration on POR; does not
affect digital output.
SEG42 0O ANA LCD Segment 42 output; disables all other pin functions.
RH7/AN15/SE
G43
RH7 0O DIG LATH<7> data output; not affected by analog input.
1I ST PORTH<7> data input; disabled when analog input is enabled.
AN15 1I ANA A/D Input Channel 15. Default input configuration on POR; does not
affect digital output.
SEG43 0O ANA LCD Segment 43 output; disables all other pin functions.
TABLE 11-8: PORTH FUNCTIONS (CONTINUED)
Pin Name Function TRIS
Setting I/O I/O Type Description
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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11.10 PORTJ, LATJ and TRISJ Registers
PORTJ is an 8-bit wide, bidirectional port. The
corresponding Data Direction and Output Latch registers
are TRISJ and LATJ.
All pins on PORTJ are implemented with Schmitt
Trigger input buffers. Each pin is individually
configurable as an input or output.
When the external memory interface is enabled, all of
the PORTJ pins function as control outputs for the inter-
face. This occurs automatically when the interface is
enabled by clearing the EBDIS control bit
(MEMCON<7>). The TRISJ bits are also overridden.
Each of the PORTJ pins has a weak internal pull-up.
The pull-ups are provided to keep the inputs at a known
state for the external memory interface while powering
up. A single control bit can turn off all the pull-ups. This
is performed by clearing bit, RJPU (PADCFG<2>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on any device Reset.
EXAMPLE 11-9: INITIALIZING PORTJ
Note: PORTJ is available only on 80-pin and
100-pin devices.
Note: These pins are configured as digital inputs
on any device Reset.
CLRF PORTJ ; Initialize PORTJ by
; clearing output latches
CLRF LATJ ; Alternate method
; to clear output latches
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISJ ; Set RJ3:RJ0 as inputs
; RJ5:RJ4 as output
; RJ7:RJ6 as inputs
TABLE 11-9: PORTJ FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O Type Description
RJ0/SEG32/
ALE
RJ0 0O DIG LATJ<0> data output.
1I ST PORTJ<0> data input.
SEG32 0O ANA LCD Segment 32 output; disables all other pin functions.
ALE xO DIG External Memory Bus Address Latch Enable (ALE) signal.
RJ1/SEG33/OE RJ1 0O DIG LATJ<1> data output.
1I ST PORTJ<1> data input.
SEG33 0O ANA LCD Segment 33 output; disables all other pin functions.
OE xO DIG External Memory Bus Address Latch Enable (OE) signal.
RJ2/SEG34/
WRL
RJ2 0O DIG LATJ<2> data output.
1I ST PORTJ<2> data input.
SEG34 0O ANA LCD Segment 34 output; disables all other pin functions.
WRL xO DIG External Memory Bus Write Low (WRL) signal.
RJ3/SEG35/
WRH
RJ3 0O DIG LATJ<3> data output.
1I ST PORTJ<3> data input.
SEG35 0O ANA LCD Segment 35 output; disables all other pin functions.
WRH xO DIG External Memory Bus Write High (WRH) signal.
RJ4/SEG39/
BA0
RJ4 0O DIG LATJ<4> data output.
1I ST PORTJ<4> data input.
SEG39 0O ANA LCD Segment 39 output; disables all other pin functions.
BA0 xO DIG External Memory Bus Byte Access 0 (BA0) signal.
RJ5/SEG38/CE RJ5 0O DIG LATJ<5> data output.
1I ST PORTJ<5> data input.
SEG38 0O ANA LCD Segment 38 output; disables all other pin functions.
CE xO DIG External Memory Bus Chip Enable (CE) signal.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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RJ6/SEG37/LB RJ6 0O DIG LATJ<6> data output.
1I ST PORTJ<6> data input.
SEG37 0O ANA LCD Segment 37 output; disables all other pin functions.
LB xO DIG External Memory Bus Lower Byte (LB) signal.
RJ7/SEG36/UB RJ7 0O DIG LATJ<7> data output.
1I ST PORTJ<7> data input.
SEG36 0O ANA LCD Segment 36 output; disables all other pin functions.
UB xO DIG External Memory Bus Upper Byte (UB) signal.
TABLE 11-9: PORTJ FUNCTIONS (CONTINUED)
Pin Name Function TRIS
Setting I/O I/O Type Description
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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11.11 PORTK, LATK and TRISK
Registers
PORTK is an 8-bit wide, bidirectional port. The corre-
sponding Data Direction and Output Latch registers are
TRISK and LATK.
All pins on PORTK are implemented with Schmitt Trig-
ger input buffers. Each pin is individually configurable
as an input or output.
Each of the PORTK pins has a weak internal pull-up.
The pull-ups are provided to keep the inputs at a known
state for the external memory interface while powering
up. A single control bit can turn off all the pull-ups. This
is performed by clearing bit, RKPU (PADCFG<1>).
The weak pull-up is automatically turned off when the
port pin is configured as an output. The pull-ups are
disabled on any device Reset.
EXAMPLE 11-10: INITIALIZING PORTK
Note: PORTK is available only on 100-pin
devices.
BANKSEL LATK ; select bank with LATK register
CLRF LATK ; Initialize LATK
; by clearing output
; data latches
BANKSEL TRISK ; Select bank with TRISK register
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISK ; Set RH3:RH0 as inputs
; RH5:RH4 as outputs
; RH7:RH6 as inputs
TABLE 11-10: PORTK FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O Type Description
RK0/SEG56 RK0 0O DIG LATK<0> data output.
1I ST PORTK<0> data input.
SEG56 0O ANA LCD Segment 56 output; disables all other pin functions.
RK1/SEG57 RK1 0O DIG LATK<1> data output.
1I ST PORTK<1> data input.
SEG57 0O ANA LCD Segment 57 output; disables all other pin functions.
RK2/SEG58 RK2 0O DIG LATK<2> data output.
1I ST PORTK<2> data input.
SEG58 0O ANA LCD Segment 58 output; disables all other pin functions.
RK3/SEG59 RK3 0O DIG LATK<3> data output.
1I ST PORTK<3> data input.
SEG59 0O ANA LCD Segment 59 output; disables all other pin functions.
RK4/SEG60 RK4 0O DIG LATK<4> data output.
1I ST PORTK<4> data input.
SEG60 0O ANA LCD Segment 60 output; disables all other pin functions.
RK5/SEG61 RK5 0O DIG LATK<5> data output.
1I ST PORTK<5> data input.
SEG61 0O ANA LCD Segment 61 output; disables all other pin functions.
RK6/SEG62 RK6 0O DIG LATK<6> data output.
1I ST PORTK<6> data input.
SEG62 0O ANA LCD Segment 62 output; disables all other pin functions.
RK7/SEG63 RK7 0O DIG LATK<7> data output.
1I ST PORTK<7> data input.
SEG63 0O ANA LCD Segment 63 output; disables all other pin functions.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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11.12 PORTL, LATL and TRISL Registers
PORTL is an 8-bit wide, bidirectional port. The corre-
sponding Data Direction and Output Latch registers are
TRISL and LATL.
All pins on PORTL are implemented with Schmitt Trig-
ger input buffers. Each pin is individually configurable
as an input or output.
Each of the PORTL pins has a weak internal pull-up.
The pull-ups are provided to keep the inputs at a known
state for the external memory interface while powering
up. A single control bit can turn off all the pull-ups. This
is performed by clearing bit, RLPU (PADCFG<0>).
The weak pull-up is automatically turned off when the
port pin is configured as an output. The pull-ups are
disabled on any device Reset.
EXAMPLE 11-11: INITIALIZING PORTL
Note: PORTL is available only on 100-pin
devices.
BANKSEL PORTL ; select correct bank
CLRF PORTL ; Initialize PORTL by
; clearing output latches
CLRF LATL ; Alternate method
; to clear output latches
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISL ; Set RL3:RL0 as inputs
; RL5:RL4 as output
; RL7:RL6 as inputs
TABLE 11-11: PORTL FUNCTIONS
Pin Name Function TRIS
Setting I/O I/O Type Description
RL0/SEG48 RL0 0O DIG LATL<0> data output.
1I ST PORTL<0> data input.
SEG48 0O ANA LCD Segment 48 output; disables all other pin functions.
RL1/SEG49 RL1 0O DIG LATL<1> data output.
1I ST PORTL<1> data input.
SEG49 0O ANA LCD Segment 49 output; disables all other pin functions.
RL2/SEG50 RL2 0O DIG LATL<2> data output.
1I ST PORTL<2> data input.
SEG50 0O ANA LCD Segment 50 output; disables all other pin functions.
RL3/SEG51 RL3 0O DIG LATL<3> data output.
1I ST PORTL<3> data input.
SEG51 0O ANA LCD Segment 51 output; disables all other pin functions.
RL4/SEG52 RL4 0O DIG LATL<4> data output.
1I ST PORTL<4> data input.
SEG52 0O ANA LCD Segment 52 output; disables all other pin functions.
RL5/SEG53 RL5 0O DIG LATL<5> data output.
1I ST PORTL<5> data input.
SEG53 0O ANA LCD Segment 53 output; disables all other pin functions.
RL6/SEG54 RL6 0O DIG LATL<6> data output.
1I ST PORTL<6> data input.
SEG54 0O ANA LCD Segment 54 output; disables all other pin functions.
RL7/SEG55 RL7 0O DIG LATL<7> data output.
1I ST PORTL<7> data input.
SEG55 0O ANA LCD Segment 55 output; disables all other pin functions.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
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11.13 Parallel Slave Port
PORTD can function as an 8-bit-wide Parallel Slave
Port (PSP), or microprocessor port, when control bit,
PSPMODE (PSPCON<4>), is set. The port is
asynchronously readable and writable by the external
world through the RD control input pin
(RE0/AD8/LCDBIAS1/RP28/RD) and WR control input
pin (RE1/AD9/LCDBIAS2/RP29/WR).
The PSP can directly interface to an 8-bit micro-
processor data bus. The external microprocessor can
read or write the PORTD latch as an 8-bit latch.
Setting bit, PSPMODE, enables port pin,
RE0/AD8/LCDBIAS1/RP28/RD, to be the RD input,
RE1/AD9/LCDBIAS2/RP29/WR to be the WR input
and RE2/AD10/LCDBIAS3/RP30/CS to be the CS
(Chip Select) input. For this functionality, the corre-
sponding data direction bits of the TRISE register
(TRISE<2:0>) must be configured as inputs (‘111’).
A write to the PSP occurs when both the CS and WR
lines are first detected low and ends when either are
detected high. The PSPIF and IBF flag bits (PIR1<7>
and PSPCON<7>, respectively) are set when the write
ends.
A read from the PSP occurs when both the CS and RD
lines are first detected low. The data in PORTD is read
out and the OBF bit (PSPCON<6>) is set. If the user
writes new data to PORTD to set OBF, the data is
immediately read out, but the OBF bit is not set.
When either the CS or RD line is detected high, the
PORTD pins return to the input state and the PSPIF bit
is set. User applications should wait for PSPIF to be set
before servicing the PSP. When this happens, the IBF
and OBF bits can be polled and the appropriate action
taken.
The timing for the control signals in Write and Read
modes is shown in Figure 11-4 and Figure 11-5,
respectively.
FIGURE 11-3: PORTD AND PORTE
BLOCK DIAGRAM
(PARALLEL SLAVE PORT)
Note: The Parallel Slave Port is available only in
Microcontroller mode.
Data Bus
WR LATD
RDx
QD
CK
EN
QD
EN
RD PORTD
Pin
One Bit of PORTD
Set Interrupt Flag
PSPIF (PIR1<7>)
Read
Chip Select
Write
RD
CS
WR
Note: The I/O pin has protection diodes to VDD and VSS.
TTL
TTL
TTL
TTL
or
PORTD
RD LATD
Data Latch
TRIS Latch
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FIGURE 11-4: PARALLEL SLAVE PORT WRITE WAVEFORMS
REGISTER 11-4: PSPCON: PARALLEL SLAVE PORT CONTROL REGISTER
R-0 R-0 R/W-0 R/W-0 U-0 U-0 U-0 U-0
IBF OBF IBOV PSPMODE — — — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 IBF: Input Buffer Full Status bit
1 = A word has been received and is waiting to be read by the CPU
0 = No word has been received
bit 6 OBF: Output Buffer Full Status bit
1 = The output buffer still holds a previously written word
0 = The output buffer has been read
bit 5 IBOV: Input Buffer Overflow Detect bit
1 = A write occurred when a previously input word had not been read (must be cleared in software)
0 = No overflow occurred
bit 4 PSPMODE: Parallel Slave Port Mode Select bit
1 = Parallel Slave Port mode
0 = General Purpose I/O mode
bit 3-0 Unimplemented: Read as ‘0’
Q1 Q2 Q3 Q4
CS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
WR
RD
IBF
OBF
PSPIF
PORTD<7:0>
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FIGURE 11-5: PARALLEL SLAVE PORT READ WAVEFORMS
Q1 Q2 Q3 Q4
CS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
WR
IBF
PSPIF
RD
OBF
PORTD<7:0>
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11.14 Virtual PORT
This device includes a single virtual port, which is used
to construct a logically addressed 8-bit PORT from
8 physically unrelated pins on the device. The virtual
PORT is controlled through the PORTVR, LATVR and
TRISVR registers. These function identically to the
PORT, LAT and TRIS registers of the actual I/O ports.
Refer to Section 11.1 “I/O Port Pin Capabilities” for
more information.
11.15 PPS-Lite
Previous PIC18 devices had I/O pins that were
“hard-wired” to a set of peripherals. For example, a port
pin might have had the option of serving as an I/O pin,
an analog input or as an interrupt source. In an effort to
increase the flexibility of the parts, PIC18F97J94
devices contain PPS-Lite (Peripheral Pin Select-Lite),
which allows the developer to connect an internal
peripheral to a subset of pins. PPS-Lite is similar to
PPS (available on PIC18F products), but limits the user
to interconnections within four sets of pin/peripheral
groups.
The PPS-Lite feature allows some flexibility in choosing
which peripheral connects to any particular pin. This
allows designs to be maximized for layout efficiency,
and also may allow component changes without
changing the printed circuit board design. The Periph-
eral Pin Select feature operates over a fixed subset of
digital I/O pins (those designated as RPn pins). Users
may independently map the input and/or output of most
digital peripherals to a limited set of these I/O pins. The
PPS-Lite configuration is performed in software and
does not require the device to be reprogrammed. Hard-
ware safeguards are included that prevent accidental
or spurious changes to the peripheral mapping once it
has been established.
11.15.1 AVAILABLE PINS
The PPS-Lite feature is used with a range of pins. All
devices in the PIC18F97J94 family contain a total of
47 remappable peripheral pins, labeled RP0 through
RP46. Pins that support PPS-Lite feature include the
designation, “RPn” in their full pin designation, where
“RP” designates a remappable peripheral and “n” is the
remappable pin number. For PIC18F97J94 devices,
RP41 through RP45 are digital inputs only.
11.15.2 AVAILABLE PERIPHERALS
The peripherals managed by the Peripheral Pin Select
are all “digital only” peripherals. These include general
serial communications (USART and SPI), general pur-
pose timer clock inputs, timer related peripherals (input
capture and output compare) and external interrupt
inputs.
In comparison, some digital only peripheral modules
are not currently included in the Peripheral Pin Select
feature. This is because the peripheral’s function
requires special I/O circuitry on a specific port and can-
not be easily connected to multiple pins. These
modules include I2C, USB, change notification inputs,
RTCC alarm output and all modules with analog inputs,
such as the A/D Converter.
A key difference between remappable and
non-remappable peripherals is that remappable
peripherals are not associated with a default I/O pin. The
peripheral must always be assigned to a specific I/O pin
before it can be used. In contrast, non-remappable
peripherals are always available on a default pin, assum-
ing that the peripheral is active and not conflicting with
another peripheral.
When a remappable peripheral is active on a given I/O
pin, it takes priority over all other digital I/O and digital
communication peripherals associated with the pin.
Priority is given, regardless of the type of peripheral
that is mapped. Remappable peripherals never take
priority over any analog functions associated with the
pin.
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FIGURE 11-6: STRUCTURE OF PORT SHARED WITH PPS PERIPHERALS
I/O TRIS Enable
QD
CK
WR LAT/
TRIS Latch
I/O Pin
WR PORT
Data Bus
QD
CK
Data Latch
Read PORT
Read TRIS
n
0
WR TRIS
Peripheral 2 Output Enable
I/O
Peripheral ‘n’ Output Enable
PIO Module
Output Multiplexers
Output Function
Read LAT
0
1
Open-Drain Selection
Peripheral Input
Q
Peripheral 1 Output Enable
0
n
1
1
Peripheral Pin Select
0
n
I/O Pin 0
I/O Pin 1
I/O Pin n
1
Peripheral Input
Pin Selection
Select for the Pin
Peripheral ‘n’ Output Data
Peripheral 2 Output Data
Peripheral 1 Output Data
I/O LAT/PORT Data
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11.15.3 CONTROLLING PERIPHERAL PIN
SELECT
Peripheral Pin Select features are controlled through
two sets of Special Function Registers (SFRs): one to
map peripheral inputs and one to map peripheral
outputs. Because they are separately controlled, a par-
ticular peripheral’s input and output (if the peripheral
has both) can be placed on any selectable function with
the only constraint being that RPn peripherals and pins
can only be mapped within their own group. It is not
possible to map a peripheral to a pin outside of its
group or vice versa.
The association of a peripheral to a peripheral-selectable
pin is handled in two different ways, depending if an input
or output is being mapped.
11.15.3.1 Input Mapping
The inputs of the Peripheral Pin Select options are
mapped on the basis of the peripheral; that is, a bit field
associated with a peripheral dictates the pin it will be
mapped to. The RPINRx registers (refer to Register
X-Y and table X-Y) contain sets of 4-bit fields, with each
set associated with one of the remappable peripherals.
Programming a given peripheral’s bit field with an RPn
value maps the RPn pin to that peripheral. For any
given device, the valid range of values for any of the bit
fields corresponds to the maximum number of
peripheral Pin Selections supported by the device.
The PPS-Lite peripheral inputs and associated RPn
pins have been organized into four groups. It is not pos-
sible to map a peripheral to an RPn pin which is outside
of its group. To map a peripheral input signal to an RPn
pin, use the 4-step process as indicated in Table 11-13.
Choose the signal and the RPn pin, and the column on
the right shows which value to write to the associated
RPIN register.
The peripheral inputs that support Peripheral Pin
Selection have no default pins. Since the implemented
bit fields of RPINRx registers reset to all ‘1’s, the inputs
are all tied to VSS in the device’s default (Reset) state.
For example, to assign U1RX to RP2, write the value,
h’0, to RPINR01<3:0>. Figure 11-7 illustrates
remappable pin selection for the U1RX input.
FIGURE 11-7: REMAPPABLE INPUT FOR U1RX
RP0
RP1
RP2
RPn
0
n
1
2
U1RX Input
RPINR01<3:0>
to Peripheral
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TABLE 11-12: RPINR REGISTERS
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
RPINR52_53 PBIO7R3 PBIO7R2 PBIO7R1 PBIO7R0 PBIO6R3 PBIO6R2 PBIO6R1 PBIO6R0
RPINR50_51 PBIO5R3 PBIO5R2 PBIO5R1 PBIO5R0 PBIO4R3 PBIO4R2 PBIO4R1 PBIO4R0
RPINR48_49 PBIO3R3 PBIO3R2 PBIO3R1 PBIO3R0 PBIO2R3 PBIO2R2 PBIO2R1 PBIO2R0
RPINR46_47 PBIO1R3 PBIO1R2 PBIO1R1 PBIO1R0 PBIO0R3 PBIO0R2 PBIO0R1 PBIO0R0
RPINR44_45 T5CKIR3 T5CKIR2 T5CKIR1 T5CKIR0 T5GR3 T5GR2 T5GR1 T5GR0
RPINR42_43 T3CKIR3 T3CKIR2 T3CKIR1 T3CKIR0 T3GR3 T3GR2 T3GR1 T3GR0
RPINR40_41 T1CKIR3 T1CKIR2 T1CKIR1 T1CKIR0 T1GR3 T1GR2 T1GR1 T1GR0
RPINR38_39 T0CKIR3 T0CKIR2 T0CKIR1 T0CKIR0 CCP10R3 CCP10R2 CCP10R1 CCP10R0
RPINR36_37 CCP9R3 CCP9R2 CCP9R1 CCP9R0 CCP8R3 CCP8R2 CCP8R1 CCP8R0
RPINR34_35 CCP7R3 CCP7R2 CCP7R1 CCP7R0 CCP6R3 CCP6R2 CCP6R1 CCP6R0
RPINR32_33 CCP5R3 CCP5R2 CCP5R1 CCP5R0 CCP4R3 CCP4R2 CCP4R1 CCP4R0
RPINR30_31 MDCIN2R3 MDCIN2R2 MDCIN2R1 MDCIN2R0 MDCIN1R3 MDCIN1R2 MDCIN1R1 MDCIN1R0
RPINR28_29 MDMINR3 MDMINR2 MDMINR1 MDMINR0 INT3R3 INT3R2 INT3R1 INT3R0
RPINR26_27 INT2R3 INT2R2 INT2R1 INT2R0 INT1R3 INT1R2 INT1R1 INT1R0
RPINR24_25 IOC7R3 IOC7R2 IOC7R1 IOC7R0 IOC6R3 IOC6R2 IOC6R1 IOC6R0
RPINR22_23 IOC5R3 IOC5R2 IOC5R1 IOC5R0 IOC4R3 IOC4R2 IOC4R1 IOC4R0
RPINR20_21 IOC3R3 IOC3R2 IOC3R1 IOC3R0 IOC2R3 IOC2R2 IOC2R1 IOC2R0
RPINR18_19 IOC1R3 IOC1R2 IOC1R1 IOC1R0 IOC0R3 IOC0R2 IOC0R1 IOC0R0
RPINR16_17 ECCP3R3 ECCP3R2 ECCP3R1 ECCP3R0 ECCP2R3 ECCP2R2 ECCP2R1 ECCP2R0
RPINR14_15 ECCP1R3 ECCP1R2 ECCP1R1 ECCP1R0 FLT0R3 FLT0R2 FLT0R1 FLT0R0
RPINR12_13 SS2R3 SS2R2 SS2R1 SS2R0 SDI2R3 SDI2R2 SDI2R1 SDI2R0
RPINR10_11 SCK2R3 SCK2R2 SCK2R1 SCK2R0 SS1R3 SS1R2 SS1R1 SS1R0
RPINR8_9 SDI1R3 SDI1R2 SDI1R1 SDI1R0 SCK1R3 SCK1R2 SCK1R1 SCK1R0
RPINR6_7 U4TXR3 U4TXR2 U4TXR1 U4TXR0 U4RXR3 U4RXR2 U4RXR1 U4RXR0
RPINR4_5 U3TXR3 U3TXR2 U3TXR1 U3TXR0 U3RXR3 U3RXR2 U3RXR1 U3RXR0
RPINR2_3 U2TXR3 U2TXR2 U2TXR1 U2TXR0 U2RXR3 U2RXR2 U2RXR1 U2RXR0
RPINR0_1 U1TXR3 U1TXR2 U1TXR1 U1TXR0 U1RXR3 U1RXR2 U1RXR1 U1RXR0
PIC18F97J94 FAMILY
DS30575A-page 228 2012 Microchip Technology Inc.
TABLE 11-13: RPIN REGISTERS AND AVAILABLE FUNCTIONS
PPS-Lite Input Peripheral Group 4n PPS-Lite Input Peripheral Group 4n + 1
(1) To Map this signal (4) to the Associated RPIN Register (1) To Map this Signal (4) to the Associated RPIN Register
SDI1 RPINR8_9<7:4> SDI2 RPINR12_13<3:0>
FLT0 RPINR14_15<3:0> INT1 RPINR26_27<3:0>
IOC0 RPINR18_19<3:0> IOC1 RPINR18_19<7:4>
IOC4 RPINR22_23<3:0> IOC5 RPINR22_23<7:4>
MDCIN1 RPINR30_31<3:0> MDCIN2 RPINR30_31<7:4>
T0CKI RPINR38_39<7:4> T1CKI RPINR40_41<7:4>
T5G RPINR44_45<3:0> T1G RPINR40_41<3:0>
U3RX RPINR4_5<3:0> T3CKI RPINR42_43<7:4>
U4RX RPINR6_7<3:0> T3G RPINR42_43<3:0>
CCP5 RPINR32_33<7:4> T5CKI RPINR44_45<7:4>
CCP8 RPINR36_37<3:0> U3TX RPINR4_5<7:4>
PBIO0 RPINR46_47<3:0> U4TX RPINR6_7<7:4>
PBIO4 RPINR50_51<3:0> CCP7 RPINR34_35<7:4>
CCP9 RPINR36_37<7:4>
PBIO1 RPINR46_47<7:4>
PBIO5 RPINR50_51<7:4>
(2) with this RPn Pin (3) Write this Corresponding Value (2) with this RPn Pin (3) Write this Corresponding Value
RP0 h’0 RP1 h’0
RP4 h’1 RP5 h’1
RP8 h’2 RP9 h’2
RP12 h’3 RP13 h’3
RP16 h’4 RP17 h’4
RP20 h’5 RP21 h’5
RP24 h’6 RP25 h’6
RP28 h’7 RP29 h’7
RP32 h’8 RP33 h’8
RP36 h’9 RP37 h’9
RP40 h’A RP41 h’A
RP44 h’B RP45 h’B
— h’C — h’C
— h’D — h’D
— h’E — h’E
VSS h’F VSS h’F
2012 Microchip Technology Inc. DS30575A-page 229
PIC18F97J94 FAMILY
11.15.3.2 Output Mapping
In contrast to the inputs, the outputs of the Peripheral
Pin Select options are mapped on the basis of the pin.
In this case, a bit field associated with a particular pin
dictates the peripheral output to be mapped. The
RPORx registers contain sets of 4-bit fields, with each
associated with one RPn pin (see Register 11-5). The
value of the bit field corresponds to one of the periph-
erals and that peripheral’s output is mapped to the pin.
Each pin has a limited set of peripherals to choose
from.
The PPS-Lite peripheral outputs and associated RPn
pins have been organized into four groups. It is not
possible to map a peripheral to an RPn pin which is out-
side of its group. To map a peripheral output signal to
an RPn pin, use the 4-step process, as indicated in
Table 11-14. Choose the RPn pin and the signal; the
column on the right shows which value to write to the
associated RPORx register.
The peripheral outputs that support Peripheral Pin
Selection have no default pins. Since the RPORx reg-
isters reset to all ‘0’s, the outputs are all disconnected
in the device’s default (Reset) state.
The list of peripherals for output mapping also includes
a null value of b’0000’ because of the mapping
technique. This allows unused peripherals to not be
connected to a pin. Not all peripherals are available on
all pins. For example, the “SDO2” signal is only avail-
able on RP0, RP4, RP8, etc. The “SDO2” signal is not
available on RP1.
PPS-Lite Input Peripheral Group 4n + 2 PPS-Lite Input Peripheral Group 4n + 3
(1) To Map this Signal (4) to the Associated RPIN Register (1) To Map this Signal (4) to the Associated RPIN Register
SS1 RPINR10_11<3:0> SS2 RPINR12_13<7:4>
INT2 RPINR26_27<7:4> INT3 RPINR28_29<3:0>
IOC2 RPINR20_21<3:0> IOC3 RPINR20_21<7:4>
IOC6 RPINR24_25<3:0> IOC7 RPINR24_25<7:4>
MDMIN RPINR28_29<7:4> U1RX RPINR0_1<3:0>
U1TX RPINR0_1<7:4> U2TX RPINR2_3<7:4>
U2RX RPINR2_3<3:0> SCK1 RPINR8_9<3:0>
SCK2 RPINR10_11<7:4> ECCP1 RPINR14_15<7:4>
ECCP3 RPINR16_17<7:4> ECCP2 RPINR16_17<3:0>
CCP6 RPINR34_35<3:0> CCP4 RPINR32_33<3:0>
CCP10 RPINR38_39<3:0> PBIO3 RPINR48_49<7:4>
PBIO2 RPINR48_49<3:0> PBIO7 RPINR52_53<7:4>
PBIO6 RPINR52_53<3:0>
(2) with this RPn Pin (3) Write this Corresponding Value (2) with this RPn Pin (3) Write this Corresponding Value
RP2 h’0 RP3 h’0
RP6 h’1 RP7 h’1
RP10 h’2 RP11 h’2
RP14 h’3 RP15 h’3
RP18 h’4 RP19 h’4
RP22 h’5 RP23 h’5
RP26 h’6 RP27 h’6
RP30 h’7 RP31 h’7
RP34 h’8 RP35 h’8
RP38 h’9 RP39 h’9
RP42 h’A RP43 h’A
RP46 h’B — h’B
— h’C — h’C
— h’D — h’D
— h’E — h’E
VSS h’F VSS h’F
TABLE 11-13: RPIN REGISTERS AND AVAILABLE FUNCTIONS (CONTINUED)
PIC18F97J94 FAMILY
DS30575A-page 230 2012 Microchip Technology Inc.
FIGURE 11-8: MULTIPLEXING OF REMAPPABLE OUTPUT FOR RPn
0
3
RPORn<3:0>
I/O TRIS Setting
U1TX Output Enable
U1RTS Output Enable 4
22
OC5 Output Enable
0
3
I/O LAT/PORT Content
U1TX Output
U1RTS Output 4
22
OC5 Output
Output Enable
Output Data RPn
REGISTER 11-5: RPORn_n: REMAPPED PERIPHERAL OUTPUT REGISTER n
(FUNCTION MAPS TO PIN)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
RPORn_3 RPORn_2 RPORn_1 RPORn_0 RPIRm_3 RPIRm_2 RPIRm_1 RPIRm_0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 RPORn_<3:0>: RPn peripheral output function mapping
bit 3-0 RPmR<3:0>: RPm peripheral output function mapping
Note 1: Register values can only be changed if IOLOCK = 0.
2012 Microchip Technology Inc. DS30575A-page 231
PIC18F97J94 FAMILY
TABLE 11-14: PPS-LITE OUTPUT
PPS-Lite Output Peripheral Group 4n PPS-Lite Output Peripheral Group 4n + 1
(1) To Map this RPn Pin (4) to the Associated RPOR Register (1) To Map this RPn Pin (4) to the Associated RPOR Register
RP0 RPOR0_1<3:0> RP1 RPOR0_1<7:4>
RP4 RPOR4_5<3:0> RP5 RPOR4_5<7:4>
RP8 RPOR8_9<3:0> RP9 RPOR8_9<7:4>
RP12 RPOR12_13<3:0> RP13 RPOR12_13<7:4>
RP16 RPOR16_17<3:0> RP17 RPOR16_17<7:4>
RP20 RPOR20_21<3:0> RP21 RPOR20_21<7:4>
RP24 RPOR24_25<3:0> RP25 RPOR24_25<7:4>
RP28 RPOR28_29<3:0> RP29 RPOR28_29<7:4>
RP32 RPOR32_33<3:0> RP33 RPOR32_33<7:4>
RP36 RPOR36_37<3:0> RP37 RPOR36_37<7:4>
RP40 RPOR40_41<3:0> RP41 RPOR40_41<7:4>
RP44 RPOR44_45<3:0> RP45 RPOR44_45<7:4>
(2) with this Output Signal (3) Write this Corresponding Value (2) with this Output Signal (3) Write this Corresponding Value
Disabled h’0 Disabled h’0
U2BCLK h’1 U1BCLK h’1
U3RX_DT h’2 U3TX_CK h’2
U4RX_DT h’3 U4TX_CK h’3
SDO2 h’4 SDO1 h’4
P1D h’5 P1C h’5
P2D h’6 P2C h’6
P3B h’7 P3C h’7
CTPLS h’8 CCP7 h’8
CCP5 h’9 CCP9 h’9
CCP8 h’A C2OUT h’A
C1OUT h’B Unused h’B
Unused h’C Unused h’C
PBIO0 h’D PBIO1 h’D
PBIO4 h’E PBIO5 h’E
Reserved h’F Reserved h’F
PIC18F97J94 FAMILY
DS30575A-page 232 2012 Microchip Technology Inc.
11.15.3.3 I/O Mapping
While most peripheral signals are defined as either
input or output, some peripheral signals switch
between input and output: UnRX_DT, UnTX_CK, PBIO
and CCP. Most commonly, these signals are mapped
so that both the input and output map to the same RPn
pin. If desired, the input and output can be mapped to
separate pins. For standard peripheral operation,
ensure that both the input and output mapping
configurations select the same RPn pin.
11.15.3.4 Mapping Limitations
The control schema of Peripheral Select Pins is not lim-
ited to a small range of fixed peripheral configurations.
There are no mutual or hardware enforced lockouts
between any of the peripheral mapping SFRs. While
such mappings may be technically possible from a
configuration point of view, the user must ensure the
selected configurations are supportable from an
electrical point of view.
11.15.4 CONTROLLING CONFIGURATION
CHANGES
Because peripheral remapping can be changed during
run time, some restrictions on peripheral remapping
are needed to prevent accidental configuration
changes. PIC18F97J94 devices include two features to
prevent alterations to the peripheral map:
• Continuous state monitoring
• Configuration bit remapping lock
PPS-Lite Output Peripheral Group 4n + 2 PPS-Lite Output Peripheral Group 4n +3
(1) To Map this RPn Pin (4) to the Associated RPOR Register (1) To Map this RPn Pin (4) to the Associated RPOR Register
RP2 RPOR2_3<3:0> RP3 RPOR2_3<7:4>
RP6 RPOR6_7<3:0> RP7 RPOR6_7<7:4>
RP10 RPOR10_11<3:0> RP11 RPOR10_11<7:4>
RP14 RPOR14_15<3:0> RP15 RPOR14_15<7:4>
RP18 RPOR18_19<3:0> RP19 RPOR18_19<7:4>
RP22 RPOR22_23<3:0> RP23 RPOR22_23<7:4>
RP26 RPOR26_27<3:0> RP27 RPOR26_27<7:4>
RP30 RPOR30_31<3:0> RP31 RPOR30_31<7:4>
RP34 RPOR34_35<3:0> RP35 RPOR34_35<7:4>
RP38 RPOR38_39<3:0> RP39 RPOR38_39<7:4>
RP42 RPOR42_43<3:0> RP43 RPOR42_43<7:4>
RP46 RPOR46<3:0>
(2) with this Output Signal (3) Write this Corresponding Value (2) with this Output Signal (3) Write this Corresponding Value
Disabled h’0 Disabled h’0
U1TX_CK h’1 U1RX_DT h’1
U2RX_DT h’2 U2TX_CK h’2
U3BCLK h’3 SCK1 h’3
U4BCLK h’4 ECCP1/P1A h’4
SCK2 h’5 ECCP2/P2A h’5
P1B h’6 P3D h’6
P2B h’7 MDOUT h’7
ECCP3/P3A h’8 CCP4 h’8
CCP6 h’9 C3OUT h’9
CCP10 h’A Unused h’A
Unused h’B Unused h’B
Unused h’C Unused h’C
PBIO2 h’D PBIO3 h’D
PBIO6 h’E PBIO7 h’E
Reserved h’F Reserved h’F
TABLE 11-14: PPS-LITE OUTPUT (CONTINUED)
2012 Microchip Technology Inc. DS30575A-page 233
PIC18F97J94 FAMILY
11.15.4.1 Control Register Lock
The contents of RPINRx and RPORx registers are con-
stantly monitored in hardware by shadow registers. If
an unexpected change in any of the registers occurs
(such as cell disturbances caused by ESD or other
external events), a Configuration Mismatch Reset will
trigger.
11.15.4.2 Configuration Bit Pin Select Lock
As an additional level of safety, the device can be
configured to prevent more than one write session to
the RPINRx and RPORx registers. The IOL1WAY Con-
figuration bit (CONFIG5H<0>) blocks the IOLOCK bit
from being cleared after it has been set once.
In the default (unprogrammed) state, IOL1WAY is set,
restricting users to one write session. Programming
IOL1WAY allows users unlimited access to the Periph-
eral Pin Select registers. It is good programming prac-
tice to always set the IOLOCK bit (OSCCON2<6>) after
all changes have been made to PPS-Lite registers.
11.15.5 CONSIDERATIONS FOR
PERIPHERAL PIN SELECTION
The ability to control Peripheral Pin Selection intro-
duces several considerations into application design
that should be considered. This is particularly true for
several common peripherals which are only available
as remappable peripherals.
Before any other application code is executed, the user
must initialize the device with the proper peripheral
configuration. Since the IOLOCK is not active in the
Reset state, the peripherals can be configured, and the
IOLOCK bit can be set when configuration is complete.
Choosing the configuration requires the review of all
Peripheral Pin Selects and their pin assignments,
especially those that will not be used in the application.
In all cases, unused pin-selected peripherals should be
disabled. Unused peripherals should have their inputs
assigned to VSS. I/O pins with unused RPn functions
should be configured with the NULL (‘0’) peripheral
output.
The assignment of an RPn pin to the peripheral input or
output depends on the peripheral and its use in the
application. It is good programming practice to map
peripherals to pins immediately after Reset. This
should be done before any configuration changes to
the peripheral itself.
The assignment of a peripheral output to a particular
pin does not automatically perform any other configura-
tion of the pin’s I/O circuitry. This means adding a
pin-selectable output to a pin may mean inadvertently
driving an existing peripheral input when the output is
driven. Users must be familiar with the behavior of
other fixed peripherals that share a remappable pin. To
be safe, fixed digital peripherals that share the same
pin should be disabled when not in use.
Configuring a remappable pin for a specific peripheral
input does not automatically turn that feature on. The
peripheral must be specifically configured for operation
and enabled, as if it were tied to a fixed pin.
A final consideration is that Peripheral Pin Select func-
tions neither override analog inputs, nor reconfigure
pins with analog functions for digital I/O. If a pin is
configured as an analog input on device Reset, it must
be explicitly reconfigured as digital I/O when used with
a Peripheral Pin Select.
11.15.5.1 Basic Steps to Use Peripheral Pin
Selection Lite (PPS-Lite)
1. Disable any fixed digital peripherals on the pins
to be used.
2. Switch pins to be used for digital functionality (if
they have analog functionality) using the
ANCONx registers.
3. Clear the IOLOCK bit (OSCCON<6>) if needed
(not needed after a device Reset).
4. Set RPINRx and RPORx registers appropriately.
5. Set the IOLOCK bit (OSCCON<6>).
6. Enable and configure newly mapped PPS-Lite
peripherals.
PIC18F97J94 FAMILY
DS30575A-page 234 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 235
PIC18F97J94 FAMILY
12.0 DATA SIGNAL MODULATOR
The Data Signal Modulator (DSM) is a peripheral which
allows the user to mix a data stream, also known as a
modulator signal, with a carrier signal to produce a
modulated output.
Both the carrier and the modulator signals are supplied
to the DSM module, either internally from the output of
a peripheral, or externally through an input pin.
The carrier signal is comprised of two distinct and
separate signals: a Carrier High (CARH) signal and a
Carrier Low (CARL) signal. During the time in which the
Modulator (MOD) signal is in a logic high state, the DSM
mixes the Carrier High signal with the Modulator signal.
When the Modulator signal is in a logic low state, the
DSM mixes the Carrier Low signal with the Modulator
signal.
Using this method, the DSM can generate the following
types of key modulation schemes:
• Frequency-Shift Keying (FSK)
• Phase-Shift Keying (PSK)
• On-Off Keying (OOK)
Additionally, the following features are provided within
the DSM module:
• Carrier Synchronization
• Carrier Source Polarity Select
• Carrier Source Pin Disable
• Programmable Modulator Data
• Modulator Source Pin Disable
• Modulator Output Polarity Select
• Slew Rate Control
Figure 12-1 shows a simplified block diagram of the
Data Signal Modulator peripheral.
PIC18F97J94 FAMILY
DS30575A-page 236 2012 Microchip Technology Inc.
FIGURE 12-1: SIMPLIFIED BLOCK DIAGRAM OF THE DATA SIGNAL MODULATOR
D
Q
MDBIT
MDMIN
MSSP1 (SDO)
MSSP2 (SDO)
EUSART1 (TXX)
EUSART2 (TXX)
EUSART3 (TXX)
EUSART4 (TXX)
VSS
MDCIN1
MDCIN2
REFO1 Clock
ECCP1
ECCP2
ECCP3
CCP4
0000
0001
0010
0011
0100
0101
0110
0111
1000
1011
1001
MDCH<3:0>
MDSRC<3:0>
MDCL<3:0>
ECCP1
ECCP2
SYNC
MDCHPOL
MDCLPOL
D
Q1
0
SYNC
1
0
MDCHSYNC
MDCLSYNC
MDOUT
MDOPOL MDOE
CARH
CARL
EN
MDEN
Data Signal
Modulator
MOD
CCP5
CCP6 1010
CCP7
CCP8 1100
1101
1110
CCP9
1111
CCP10
REFO2 Clock
System Clock
ECCP3
CCP4
CCP5
CCP6
CCP7
CCP8
VSS
MDCIN1
MDCIN2
REFO1 Clock
ECCP1
ECCP2
ECCP3
CCP4
CCP5
CCP6
CCP7
CCP8
CCP9
CCP10
REFO2 CLOCK
System Clock
Switches Between
PORT Function
and DSM Output
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1101
1011
1100
1110
1111
0000
0001
0010
0011
0100
0101
0110
0111
1000
1011
1001
1010
1100
1101
1110
1111
2012 Microchip Technology Inc. DS30575A-page 237
PIC18F97J94 FAMILY
12.1 DSM Operation
The DSM module can be enabled by setting the MDEN
bit in the MDCON register. Clearing the MDEN bit in the
MDCON register disables the DSM module by auto-
matically switching the Carrier High and Carrier Low
signals to the VSS signal source. The Modulator signal
source is also switched to the MDBIT in the MDCON
register. This not only assures that the DSM module is
inactive, but that it is also consuming the least amount
of current.
The Modulation Carrier High and Modulation Carrier
Low Control registers are not affected when the MDEN
bit is cleared, and the DSM module is disabled. The
values inside these registers remain unchanged while
the DSM is inactive. The sources for the Carrier High,
Carrier Low and Modulator signals will once again be
selected when the MDEN bit is set, and the DSM
module is again enabled and active.
The modulated output signal can be disabled without
shutting down the DSM module. The DSM module will
remain active and continue to mix signals, but the out-
put value will not be sent to the MDOUT pin. During the
time that the output is disabled, the MDOUT pin will
remain low. The modulated output can be disabled by
clearing the MDOE bit in the MDCON register.
12.2 Modulator Signal Sources
The Modulator signal can be supplied from the following
sources:
• ECCP1 Signal
• ECCP2 Signal
• ECCP3 Signal
• CCP2 Signal
• CCP3 Signal
• CCP4 Signal
• CCP5 Signal
• CCP6 Signal
• CCP7 Signal
• CCP8 Signal
• MSSP1 SDO Signal (SPI mode only)
• MSSP2 SDO Signal (SPI mode only)
• EUSART1 TX1 Signal
• EUSART2 TX2 Signal
• EUSART3 TX3 Signal
• EUSART4 TX4 Signal
• External Signal on MDMIN Pin (RF0/MDMIN)
• MDBIT bit in the MDCON Register
The Modulator signal is selected by configuring the
MDSRC<3:0> bits in the MDSRC register.
12.3 Carrier Signal Sources
The Carrier High signal and Carrier Low signal can be
supplied from the following sources:
• ECCP1 Signal
• ECCP2 Signal
• ECCP3 Signal
• CCP5 Signal
• CCP6 Signal
• CCP7 Signal
• CCP8 Signal
• CCP9 Signal
• CCP10 Signal
• Reference Clock Output Module Signal (REFO1)
• Reference Clock Output Module Signal (REFO2)
•System Clock
• External Signals on the MDCIN1 and MDCIN2
pins are available though PPS. Refer to
Section 11.15 “PPS-Lite” for setup.
•V
SS
The Carrier High signal is selected by configuring the
MDCH<3:0> bits in the MDCARH register. The Carrier
Low signal is selected by configuring the MDCL<3:0>
bits in the MDCARL register.
12.4 Carrier Synchronization
During the time when the DSM switches between
Carrier High and Carrier Low signal sources, the carrier
data in the modulated output signal can become
truncated. To prevent this, the carrier signal can be
synchronized to the Modulator signal. When synchroni-
zation is enabled, the carrier pulse that is being mixed
at the time of the transition is allowed to transition low
before the DSM switches over to the next carrier
source.
Synchronization is enabled separately for the Carrier
High and Carrier Low signal sources. Synchronization
for the Carrier High signal can be enabled by setting
the MDCHSYNC bit in the MDCARH register. Synchro-
nization for the Carrier Low signal can be enabled by
setting the MDCLSYNC bit in the MDCARL register.
Figure 12-1 through Figure 12-6 show timing diagrams
using various synchronization methods.
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DS30575A-page 238 2012 Microchip Technology Inc.
FIGURE 12-2: ON-OFF KEYING (OOK) SYNCHRONIZATION
FIGURE 12-3: NO SYNCHRONIZATION (MDCHSYNC = 0, MDCLSYNC = 0)
FIGURE 12-4: CARRIER HIGH SYNCHRONIZATION (MDCHSYNC = 1, MDCLSYNC = 0)
Carrier Low (CARL)
MDCHSYNC = 1
MDCLSYNC = 0
MDCHSYNC = 1
MDCLSYNC = 1
MDCHSYNC = 0
MDCLSYNC = 0
MDCHSYNC = 0
MDCLSYNC = 1
Carrier High (CARH)
Modulator (MOD)
MDCHSYNC = 0
MDCLSYNC = 0
Modulator (MOD)
Carrier High (CARH)
Carrier Low (CARL)
Active Carrier CARH CARL CARL
CARH
State
MDCHSYNC = 1
MDCLSYNC = 0
Modulator (MOD)
Carrier High (CARH)
Carrier Low (CARL)
Active Carrier
CARH CARL CARL
CARH
State
both both
2012 Microchip Technology Inc. DS30575A-page 239
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FIGURE 12-5: CARRIER LOW SYNCHRONIZATION (MDCHSYNC = 0, MDCLSYNC = 1)
FIGURE 12-6: FULL SYNCHRONIZATION (MDCHSYNC = 1, MDCLSYNC = 1)
MDCHSYNC = 0
MDCLSYNC = 1
Modulator (MOD)
Carrier High (CARH)
Carrier Low (CARL)
Active Carrier CARH CARL CARLCARH
State
MDCHSYNC = 1
MDCLSYNC = 1
Modulator (MOD)
Carrier High (CARH)
Carrier Low (CARL)
Active Carrier CARH CARL CARLCARH
State
Falling edges
used to sync
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12.5 Carrier Source Polarity Select
The signal provided from any selected input source for
the Carrier High and Carrier Low signals can be
inverted. Inverting the signal for the Carrier High source
is enabled by setting the MDCHPOL bit of the
MDCARH register. Inverting the signal for the Carrier
Low source is enabled by setting the MDCLPOL bit of
the MDCARL register.
12.6 Carrier Source Pin Disable
Some peripherals assert control over their correspond-
ing output pin when they are enabled. For example,
when the CCP1 module is enabled, the output of CCP1
is connected to the CCP1 pin.
This default connection to a pin can be disabled by
setting the MDCHODIS bit in the MDCARH register for
the Carrier High source and the MDCLODIS bit in the
MDCARL register for the Carrier Low source.
12.7 Programmable Modulator Data
The MDBIT of the MDCON register can be selected as
the source for the Modulator signal. This gives the user
the ability to program the value used for modulation.
12.8 Modulator Source Pin Disable
The Modulator source default connection to a pin can
be disabled by setting the MDSODIS bit in the MDSRC
register.
12.9 Modulated Output Polarity
The modulated output signal provided on the MDOUT
pin can also be inverted. Inverting the modulated out-
put signal is enabled by setting the MDOPOL bit of the
MDCON register.
12.10 Slew Rate Control
When modulated data streams of 20 MHz or greater
are required, the slew rate limitation on the output port
pin can be disabled. The slew rate limitation can be
removed by clearing the MDSLR bit in the MDCON
register.
12.11 Operation In Sleep Mode
The DSM module is not affected by Sleep mode. The
DSM can still operate during Sleep if the carrier and
Modulator input sources are also still operable during
Sleep.
12.12 Effects of a Reset
Upon any device Reset, the Modulator data signal
module is disabled. The user’s firmware is responsible
for initializing the module before enabling the output.
The registers are reset to their default values.
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REGISTER 12-1: MDCON: MODULATION CONTROL REGISTER
R/W-0 R/W-0 R/W-1 R/W-0 R/W-0 U-0 U-0 R/W-0
MDEN MDOE MDSLR MDOPOL MDOUT(2)——MDBIT
(1)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 MDEN: Modulator Module Enable bit
1 = Modulator module is enabled and mixing input signals
0 = Modulator module is disabled and has no output
bit 6 MDOE: Modulator Module Pin Output Enable bit
1 = Modulator pin output is enabled
0 = Modulator pin output is disabled
bit 5 MDSLR: MDOUT Pin Slew Rate Limiting bit
1 = MDOUT pin slew rate limiting is enabled
0 = MDOUT pin slew rate limiting is disabled
bit 4 MDOPOL: Modulator Output Polarity Select bit
1 = Modulator output signal is inverted
0 = Modulator output signal is not inverted
bit 3 MDOUT: Modulator Output bit(2)
Displays the current output value of the Modulator module.
bit 2-1 Unimplemented: Read as ‘0’
bit 0 MDBIT: Modulator Source Input bit(1)
Allows software to manually set modulation source input to the module.
Note 1: The MDBIT must be selected as the modulation source in the MDCON register for this operation.
2: The modulated output frequency can be greater and asynchronous from the clock that updates this
register bit. The bit value may not be valid for higher speed Modulator or carrier signals.
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REGISTER 12-2: MDSRC: MODULATION SOURCE CONTROL REGISTER
R/W-x U-0 U-0 U-0 R/W-x R/W-x R/W-x R/W-x
MDSODIS — — — MDSRC3 MDSRC2 MDSRC1 MDSRC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 MDSODIS: Modulation Source Output Disable bit
1 = Output signal driving the peripheral output pin (selected by MDMS<3:0>) is disabled
0 = Output signal driving the peripheral output pin (selected by MDMS<3:0>) is enabled
bit 6-4 Unimplemented: Read as ‘0’
bit 3-0 MDSRC<3:0> Modulation Source Selection bits
1111 = CCP8 output (PWM Output mode only)
1110 = CCP7 output (PWM Output mode only)
1101 = CCP6 output (PWM Output mode only)
1100 = CCP5 output (PWM Output mode only)
1011 = CCP4 output (PWM Output mode only)
1010 = ECCP3 output (PWM Output mode only)
1001 = ECCP2 output (PWM Output mode only)
1000 = ECCP1 output (PWM Output mode only)
0111 = EUSART4 TXx output
0110 = EUSART3 TXx output
0101 = EUSART2 TXx output
0100 = EUSART1 TXx output
0011 = MSSP2 SDO signal (SPI mode only)
0010 = MSSP1 SDO signal (SPI mode only)
0001 = MDMIN pin
0000 = MDBIT bit of MDCON register is the modulation source
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REGISTER 12-3: MDCARH: MODULATION CARRIER HIGH CONTROL REGISTER
R/W-x R/W-x R/W-x U-0 R/W-x R/W-x R/W-x R/W-x
MDCHODIS MDCHPOL MDCHSYNC — MDCH3(1)MDCH2(1)MDCH1(1)MDCH0(1)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 MDCHODIS: Modulator Carrier High Output Disable bit
1 = Output signal driving the peripheral output pin (selected by MDCH<3:0>) is disabled
0 = Output signal driving the peripheral output pin (selected by MDCH<3:0>) is enabled
bit 6 MDCHPOL: Modulator Carrier High Polarity Select bit
1 = Selected Carrier High signal is inverted
0 = Selected Carrier High signal is not inverted
bit 5 MDCHSYNC: Modulator Carrier High Synchronization Enable bit
1 = Modulator waits for a falling edge on the Carrier High time signal before allowing a switch to the
Carrier Low time
0 = Modulator output is not synchronized to the Carrier High time signal(1)
bit 4 Unimplemented: Read as ‘0’
bit 3-0 MDCH<3:0>: Modulator Data Carrier High Selection bits(1)
1111 = Reference Clock Output Module 2 (REFO2) signal
1110 = System clock
1101 = CCP10 output (PWM Output mode only)
1100 = CCP9 output (PWM Output mode only)
1011 = CCP8 output (PWM Output mode only)
1010 = CCP7 output (PWM Output mode only)
1001 = CCP6 output (PWM Output mode only)
1000 = CCP5 output (PWM Output mode only)
0111 = CCP4 output (PWM Output mode only)
0110 = ECCP3 output (PWM Output mode only)
0101 = ECCP2 output (PWM Output mode only)
0100 = ECCP1 output (PWM Output mode only)
0011 = Reference Clock Output Module 1 (REFO1) signal
0010 = MDCIN2 pin
0001 = MDCIN1 pin
0000 = No carrier input (tied to ground)
Note 1: Narrowed carrier pulse widths or spurs may occur in the signal stream during transitions.
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REGISTER 12-4: MDCARL: MODULATION CARRIER LOW CONTROL REGISTER
R/W-x R/W-x R/W-x U-0 R/W-x R/W-x R/W-x R/W-x
MDCLODIS MDCLPOL MDCLSYNC — MDCL3(1)MDCL2(1)MDCL1(1)MDCL0(1)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 MDCLODIS: Modulator Carrier Low Output Disable bit
1 = Output signal driving the peripheral output pin (selected by MDCL<3:0>) is disabled
0 = Output signal driving the peripheral output pin (selected by MDCL<3:0>) is enabled
bit 6 MDCLPOL: Modulator Carrier Low Polarity Select bit
1 = Selected Carrier Low signal is inverted
0 = Selected Carrier Low signal is not inverted
bit 5 MDCLSYNC: Modulator Carrier Low Synchronization Enable bit
1 = Modulator waits for a falling edge on the Carrier Low time signal before allowing a switch to the
Carrier High time
0 = Modulator output is not synchronized to the Carrier Low time signal(1)
bit 4 Unimplemented: Read as ‘0’
bit 3-0 MDCL<3:0>: Modulator Data Carrier Low Selection bits(1)
1111 = Reference Clock Output Module 2 (REFO2) signal
1110 = System clock
1101 = CCP10 output (PWM Output mode only)
1100 = CCP9 output (PWM Output mode only)
1011 = CCP8 output (PWM Output mode only)
1010 = CCP7 output (PWM Output mode only)
1001 = CCP6 output (PWM Output mode only)
1000 = CCP5 output (PWM Output mode only)
0111 = CCP4 output (PWM Output mode only)
0110 = ECCP3 output (PWM Output mode only)
0101 = ECCP2 output (PWM Output mode only)
0100 = ECCP1 output (PWM Output mode only)
0011 = Reference Clock Output Module 1 (REFO1) signal
0010 = MDCIN2 pin
0001 = MDCIN1 pin
0000 = No carrier input (tied to ground)
Note 1: Narrowed carrier pulse widths or spurs may occur in the signal stream during transitions.
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13.0 LIQUID CRYSTAL DISPLAY
(LCD) CONTROLLER
The Liquid Crystal Display (LCD) driver module gener-
ates the timing control to drive a static or multiplexed
LCD panel. In 100-pin devices (PIC18F97J94), the
module drives panels of up to eight commons and up to
60 segments when 5 to 8 commons are used, and up
to 64 segments when 1 to 4 commons are used. It also
provides control of the LCD pixel data.
The LCD driver module supports:
• Direct driving of LCD panel
• Three LCD clock sources with selectable prescaler
• Up to eight commons:
- Static (One common)
- 1/2 multiplex (two commons)
- 1/3 multiplex (three commons)
- 1/8 multiplex (eight commons)
• Up to 60 segments (in 100-pin devices when
1/5-1/8 multiplex is selected), 64 (in 100-pin
devices when up to 1/4 multiplex is selected), 46
(in 80-pin devices when 1/5-1/8 multiplex is
selected), 50 (in 80-pin devices when up to
1/4 multiplex is selected), 30 (in 64-pin devices
when 1/5-1/8 multiplex is selected) and 34 (in
64-pin devices when up to 1/4 multiplex is
selected)
• Static, 1/2 or 1/3 LCD bias
• On-chip bias generator with dedicated charge
pump to support a range of fixed and variable bias
options
• Internal resistors for bias voltage generation
• Software contrast control for LCD using the
internal biasing
A simplified block diagram of the module is shown in
Figure 13-1.
FIGURE 13-1: LCD CONTROLLER MODULE BLOCK DIAGRAM
COM<7:0>
Timing Control
Data Bus
SOSC
FRC Oscillator
LPRC Oscillator
512
to
64
MUX SEG<63:0>
To I/O Pins
64 x 8
LCD DATA
LCDCONL
LCDPSL
LCDSEx
LCDDATA0
LCDDATA1
LCDDATA62
LCDDATA63
.
.
.
LCD Bias Generation
LCD Clock
Source Select
LCD
Charge Pump
64
8
Bias
Voltage
8
(Secondary Oscillator)
Resistor Ladder
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13.1 LCD Registers
The LCD controller has up to 77 registers:
• LCD Control Register (LCDCON)
• LCD Phase Register (LCDPS)
• LCD Voltage Regulator Control Register
(LCDREG)
• LCD Reference Ladder Control Register
High/Low (LCDREFH and LCDREFL)
• Eight LCD Segment Enable Registers
(LCDSE7:LCDSE0)
• 64 LCD Data Registers
(LCDDATA63:LCDDATA0)
The LCDCON register, shown in Register 13-1, con-
trols the overall operation of the module. Once the
module is configured, the ON (LCDCON<15>) bit is
used to enable or disable the LCD module. The LCD
panel can also operate during Sleep by clearing the
SLPEN (LCDCON<6>) bit.
The LCDPS register, shown in Register 13-3, configures
the LCD clock source prescaler and the type of wave-
form: Type-A or Type-B. For details on these features,
see Section 13.3 “LCD Clock Source Selection” and
Section 13.12 “LCD Waveform Generation”.
REGISTER 13-1: LCDCON: LCD CONTROL REGISTER
R/W-0 R/W-0 R/C-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ON SLPEN WERR CS1 CS0 LMUX2 LMUX1 LMUX0
bit 7 bit 0
Legend: C = Clearable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ON: LCD Driver Enable bit
1 = LCD driver module is enabled
0 = LCD driver module is disabled
bit 6 SLPEN: LCD Driver Enable in Sleep mode bit
1 = LCD driver module is disabled in Sleep mode
0 = LCD driver module is enabled in Sleep mode
bit 5 WERR: LCD Write Failed Error bit
1 = LCDDATAx register is written while WA (LCDPS<4>) = 0 (must be cleared in software)
0 = No LCD write error
bit 4-3 CS<1:0>: Clock Source Select bits
00 = FRC (8 MHz)/8192
01 = SOSC Oscillator (32.768 kHz)/32
1x = INTRC (31.25 kHz)/32
bit 2-0 LMUX<2:0>: Commons Select bits
LMUX<2:0> Multiplex Bias
111 1/8 MUX (COM<7:0>) 1/3
110 1/7 MUX (COM<6:0>) 1/3
101 1/6 MUX (COM<5:0>) 1/3
100 1/5 MUX (COM<4:0>) 1/3
011 1/4 MUX (COM<3:0>) 1/3
010 1/3 MUX (COM<2:0>) 1/2 or 1/3
001 1/2 MUX (COM<1:0>) 1/2 or 1/3
000 Static (COM0) Static
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REGISTER 13-2: LCDREG: LCD CHARGE PUMP CONTROL REGISTER
R/W-0 U-0 RW-1 RW-1 RW-1 RW-1 RW-0 RW-0
CPEN — BIAS2 BIAS1 BIAS0 MODE13 CLKSEL1 CLKSEL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CPEN: 3.6V Charge Pump Enable bit
1 = The regulator generates the highest (3.6V) voltage
0 = Highest voltage in the system is supplied externally (VDD)
bit 6 Unimplemented: Read as ‘0’
bit 5-3 BIAS<2:0>: Regulator Voltage Output Control bits
111 = 3.60V peak (offset on LCDBIAS0 of 0V)
110 = 3.47V peak (offset on LCDBIAS0 of 0.13V)
101 = 3.34V peak (offset on LCDBIAS0 of 0.26V)
100 = 3.21V peak (offset on LCDBIAS0 of 0.39V)
011 = 3.08V peak (offset on LCDBIAS0 of 0.52V)
010 = 2.95V peak (offset on LCDBIAS0 of 0.65V)
001 = 2.82V peak (offset on LCDBIAS0 of 0.78V)
000 = 2.69V peak (offset on LCDBIAS0 of 0.91V)
bit 2 MODE13: 1/3 LCD BIAS Enable bit
1 = Regulator output supports 1/3 LCD BIAS mode
0 = Regulator output supports Static LCD BIAS mode
bit 1-0 CLKSEL<1:0>: Regulator Clock Select Control bits
11 =LPRC
10 =FRC
01 =SOSC
00 = Disable regulator and float regulator voltage output.
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REGISTER 13-3: LCDPS: LCD PHASE REGISTER
R/W-0 R/W-0 R-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0
WFT BIASMD LCDA WA LP3 LP2 LP1 LP0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 WFT: Waveform Type Select bit
1 = Type-B waveform (phase changes on each frame boundary)
0 = Type-A waveform (phase changes within each common type)
bit 6 BIASMD: Bias Mode Select bit
When LMUX<2:0> = 000 or 011 through 111:
0 = Static Bias mode (LMUX<2:0> = 000) / 1/3 Bias mode (LMUX<2:0> = 011 through 111) (do not
set this bit to ‘1’)
When LMUX<2:0> = 001 or 010:
1 = 1/2 Bias mode
0 = 1/3 Bias mode
bit 5 LCDA: LCD Active Status bit
1 = LCD driver module is active
0 = LCD driver module is inactive
bit 4 WA: LCD Write Allow Status bit
1 = Writes into the LCDDATAx registers is allowed
0 = Writes into the LCDDATAx registers is not allowed
bit 3-0 LP<3:0>: LCD Prescaler Select bits
1111 = 1:16
1110 = 1:15
1101 = 1:14
1100 = 1:13
1011 = 1:12
1010 = 1:11
1001 = 1:10
1000 = 1:9
0111 = 1:8
0110 = 1:7
0101 = 1:6
0100 = 1:5
0011 = 1:4
0010 = 1:3
0001 = 1:2
0000 = 1:1
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13.2 LCD Segment Pins Configuration
The LCDSEx registers configure the functions of the
port pins. Setting the segment enable bit for a particular
segment configures that pin as an LCD driver. There
are four LCD Segment Enable registers, as shown in
Table 13-1. The prototype LCDSEx register is shown in
Register 13-4.
Once the module is initialized for the LCD panel, the
individual bits of the LCDDATAx registers are cleared
or set to represent a clear or dark pixel, respectively.
Specific sets of LCDDATA registers are used with
specific segments and common signals. Each bit rep-
resents a unique combination of a specific segment
connected to a specific common.
Individual LCDDATA bits are named by the convention,
“SxxCy”, with “xx” as the segment number and “y” as
the common number. The relationship is summarized
in Register 13-3. The prototype LCDDATAx register is
shown in Register 13-5.
REGISTER 13-4: LCDSEx: LCD SEGMENT x ENABLE REGISTER
TABLE 13-1: LCDSEx REGISTERS AND ASSOCIATED SEGMENTS
Register Segments
LCDSE0 Seg 7:Seg 0
LCDSE1 Seg 15:Seg 8
LCDSE2 Seg 23:Seg 16
LCDSE3 Seg 31:Seg 24
LCDSE4 Seg 39:Seg 32
LCDSE5 Seg 47:Seg 40
LCDSE6 Seg 55:Seg 48
LCDSE7 Seg 63:Seg 56
Note: Not all LCDSEx and LCDDATAx registers
are implemented in lower pin count
devices. Refer to the specific device data
sheet for more details.
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
SE(n) SE(n) SE(n) SE(n) SE(n) SE(n) SE(n) SE(n)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 SE(n): Segment Enable bits
For LCDSE0: n = 0-7
For LCDSE1: n = 8-15
For LCDSE2: n = 16-23
For LCDSE3: n = 24-31
For LCDSE0: n = 32-39
For LCDSE0: n = 40-47
For LCDSE0: n = 48-55
For LCDSE0: n = 56-63
1 = Segment function of the pin is enabled, digital I/O is disabled
0 = Segment function of the pin is disabled, digital I/O is enabled
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REGISTER 13-5: LCDDATAx: LCD DATA x REGISTER
TABLE 13-2: LCDDATA REGISTERS AND BITS FOR SEGMENT AND COM COMBINATIONS
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
S(n)Cy S(n)Cy S(n)Cy S(n)Cy S(n)Cy S(n)Cy S(n)Cy S(n)Cy
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 S(n)Cy: Pixel On bits
For registers LCDDATA0 through LCDDATA7: n = (0-63), y = 0
For registers LCDDATA8 through LCDDATA15: n = (0-63), y = 1
For registers LCDDATA16 through LCDDATA23: n = (0-63), y = 2
For registers LCDDATA24 through LCDDATA31: n = (0-63), y = 3
For registers LCDDATA32 through LCDDATA39: n = (0-63), y = 4
For registers LCDDATA40 through LCDDATA47: n = (0-63), y = 5
For registers LCDDATA48 through LCDDATA55: n = (0-63), y = 6
For registers LCDDATA56 through LCDDATA63: n = (0-63), y = 7
1 = Pixel on
0 = Pixel off
COM
Lines
Segments
0 to 7 8 to 15 16 to 23 24 to 31 32 to 39 40 to 47 48 to 55 56 to 63
0LCDDATA0
S00C0:S07C0
LCDDATA1
S08C0:S15C0
LCDDATA2
S16C0:S23C0
LCDDATA3
S24C0:S31C0
LCDDATA4
S32C0:S39C0
LCDDATA5
S40C0:S47C0
LCDDATA6
S48C0:S55C0
LCDDATA7
S56C0:S63C0
1LCDDATA8
S00C1:S07C1
LCDDATA9
S08C1:S15C1
LCDDATA10
S16C1:S23C1
LCDDATA11
S24C1:S31C1
LCDDATA12
S32C1:S39C1
LCDDATA13
S40C1:S47C1
LCDDATA14
S48C1:S55C1
LCDDATA15
S56C1:S63C1
2LCDDATA16
S00C2:S07C2
LCDDATA17
S08C2:S15C2
LCDDATA18
S16C2:S23C2
LCDDATA19
S24C2:S31C2
LCDDATA20
S32C2:S39C2
LCDDATA21
40C2:S47C2
LCDDATA22
S48C2:S55C2
LCDDATA23
S56C2:S63C2
3LCDDATA24
S00C3:S07C3
LCDDATA25
S08C3:S15C3
LCDDATA26
S16C3:S23C3
LCDDATA27
S24C3:S31C3
LCDDATA28
S32C3:S39C3
LCDDATA29
S40C3:S47C3
LCDDATA30
S48C3:S55C3
LCDDATA31
S56C3:S63C3
4LCDDATA32
S00C4:S07C4
LCDDATA33
S08C4:S15C4
LCDDATA34
S16C4:S23C4
LCDDATA35
S24C4:S31C4
LCDDATA36
S32C4:S39C4
LCDDATA37
S40C4:S47C4
LCDDATA38
S48C4:S55C4
LCDDATA39
S56C4:S63C4
5LCDDATA40
S00C5:S07C5
LCDDATA41
S08C5:S15C5
LCDDATA42
S16C5:S23C5
LCDDATA43
S24C5:S31C5
LCDDATA44
S32C5:S39C5
LCDDATA45
S40C5:S47C5
LCDDATA46
S48C5:S55C5
LCDDATA47
S56C5:S63C5
6LCDDATA48
S00C6:S07C6
LCDDATA49
S08C6:S15C6
LCDDATA50
S16C6:S23C6
LCDDATA51
S24C6:S31C6
LCDDATA52
S32C6:S39C6
LCDDATA53
S40C6:S47C6
LCDDATA54
S48C6:S55C6
LCDDATA55
S56C6:S63C6
7LCDDATA56
S00C7:S07C7
LCDDATA57
S08C7:S15C7
LCDDATA58
S16C7:S23C7
LCDDATA59
S24C7:S31C7
LCDDATA60
S32C7:S39C7
LCDDATA61
S40C7:S47C7
LCDDATA62
S48C7:S55C7
LCDDATA63
S56C7:S63C7
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13.3 LCD Clock Source Selection
The LCD driver module has three possible clock
sources:
• FRC/8192
• SOSC Clock/32
• LPRC/32
The first clock source is the 8 MHz Fast Internal RC
(FRC) Oscillator divided by 8,192. This divider ratio is
chosen to provide about 1 kHz output. The divider is
not programmable. Instead, the LCD prescaler bits,
LCDPS<3:0>, are used to set the LCD frame clock
rate.
The second clock source is the SOSC Oscillator/32.
This also outputs about 1 kHz when a 32.768 kHz
crystal is used with the SOSC Oscillator. To use the
SOSC Oscillator as a clock source, set the SOSCEN
(T1CON<3>) bit.
The third clock source is a 31.25 kHz internal LPRC
Oscillator/32 that provides approximately 1 kHz output.
The second and third clock sources may be used to
continue running the LCD while the processor is in
Sleep.
These clock sources are selected through the bits,
CS<1:0> (LCDCON<4:3>).
13.3.1 LCD PRESCALER
A 16-bit counter is available as a prescaler for the LCD
clock. The prescaler is not directly readable or writable.
Its value is set by the LP<3:0> bits (LCDPS<3:0>) that
determine the prescaler assignment and prescale ratio.
Selectable prescale values are from 1:1 through 1:16,
in increments of one.
FIGURE 13-2: LCD CLOCK GENERATION
CS<1:0>
SOSC Oscillator
(32 kHz)
÷4
LMUX<2:0>
4-Bit Prog Prescaler ÷1, 2, 3....8
Ring Counter
LMUX<2:0>
COM0
COM1
COM2
COM7
÷8192
÷2
÷32
÷32 LP<3:0>
(LCDCON<4:2>) (LCDCON<2:0>)
(LCDCON<2:0>)
(LCDPS<3:0>)
FRC Oscillator
(8 MHZ)
LPRC Oscillator
(31.25 kHz)
STAT
1/2 MUX
1/3 to 1/8
MUX
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13.4 LCD Bias Types
The LCD module can be configured in one of three bias
types:
• Static bias (two voltage levels: VSS and VDD)
• 1/2 bias (three voltage levels: VSS, 1/2 VDD and
VDD)
• 1/3 bias (four voltage levels: VSS, 1/3 VDD, 2/3
VDD and VDD)
LCD bias voltages can be generated with an internal
resistor ladders, internal bias generator or external
resistor ladder.
13.5 Internal Resistor Biasing
This mode does not use external resistors, but rather
internal resistor ladders that are configured to generate
the bias voltage.
The internal reference ladder actually consists of three
separate ladders. Disabling the internal reference lad-
der disconnects all of the ladders, allowing external
voltages to be supplied.
Depending on the total resistance of the resistor
ladders, the biasing can be classified as low, medium
or high power.
Table 13-3 shows the total resistance of each of the
ladders. Ta b le 1 3- 3 shows the internal resister ladder
connections. When the internal resistor ladder is
selected, the bias voltage can either be from VDD or
from VDDCORE, depending on the LCDIRS setting. It
can also provide software contrast control (using
LCDCST<2:0>)
.
TABLE 13-3: INTERNAL RESISTANCE LADDER POWER MODES
Power Mode
Nominal
Resistance of
Entire Ladder
IDD
Low 3 MΩ1 µA
Medium 300 kΩ10 µA
High 30 kΩ100 µA
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FIGURE 13-3: LCD BIAS INTERNAL RESISTOR LADDER CONNECTION DIAGRAM
There are two power modes, designated as “Mode A”
and “Mode B”. Mode A is set by the LRLAP<1:0> bits
and Mode B by the LRLB<1:0> bits. The resistor ladder
to use for Modes A and B are selected by the bits,
LRLAP<1:0> and LRLBP<1:0>, respectively.
Each ladder has a matching contrast control ladder,
tuned to the nominal resistance of the reference ladder.
This contrast control resistor can be controlled by the
LCDCST<2:0> bits (LCDREFH<5:3>). Disabling the
internal reference ladder results in all of the ladders
being disconnected, allowing external voltages to be
supplied.
To get additional current in High-Power mode, when
LRLAP<1:0> (LCDREFL<7:6>) = 11, both the medium
and high-power resistor ladders are activated.
Whenever the LCD module is inactive, LCDA
(LCDPS<5>) = 0), the reference ladder will be turned
off.
LCDBIAS3
LCDBIAS2
LCDBIAS1
VLCD3PE
VLCD2PE
VLCD1PE
LCDCST<2:0>
LCDIRE
LCDIRS
VDD
3x Band Gap
LRLAT<2:0>
A Power Mode
B Power Mode
LRLAP<1:0> LRLBP<1:0>
Low
Resistor
Ladder
Medium
Resistor
Ladder
High
Resistor
Ladder
VDD
VDDCORE
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13.5.1 AUTOMATIC POWER MODE
SWITCHING
As an LCD segment is electrically only a capacitor, cur-
rent is drawn only during the interval when the voltage
is switching. To minimize total device current, the LCD
reference ladder can be operated in a different power
mode for the transition portion of the duration. This is
controlled by the LCDREFH/L registers.
Mode A Power mode is active for a programmable
time, beginning at the time when the LCD segment
waveform is transitioning. The LRLAT<2:0> bits
(LCDREFL<2:0>) select how long or if the Mode A is
active. Mode B Power mode is active for the remaining
time before the segments or commons change again.
As shown in Figure 13-4, there are 32 counts in a single
segment time. Type-A can be chosen during the time
when the wave form is in transition. Type-B can be
used when the clock is stable or not in transition.
By using this feature of automatic power switching
using Type-A/Type-B, the power consumption can be
optimized for a given contrast.
FIGURE 13-4: LCD REFERENCE LADDER POWER MODE SWITCHING DIAGRAM
Single Segment Time
'H00 'H01 'H02 'H03 'H04 'H05 'H06 'H07 'H1E 'H1F 'H00 'H01
'H3
Power Mode A Power Mode B Mode A
LRLAT<2:0>
lcd_32x_clk
cnt<4:0>
lcd_clk
LRLAT<2:0>
Segment Data
Power Mode
2012 Microchip Technology Inc. DS30575A-page 255
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13.5.2 CONTRAST CONTROL
The LCD contrast control circuit consists of a 7-tap
resistor ladder, controlled by the LCDCSTx bits (see
Figure 13-5)
FIGURE 13-5: INTERNAL REFERENCE AND CONTRAST CONTROL BLOCK DIAGRAM
13.5.3 INTERNAL REFERENCE
Under firmware control, an internal reference for the
LCD bias voltages can be enabled. When enabled, the
source of this voltage can be VDD.
When no internal reference is selected, the LCD con-
trast control circuit is disabled and LCD bias must be
provided externally. Whenever the LCD module is inac-
tive (LCDA = 0), the internal reference will be turned
off.
13.5.4 VLCDxPE PINS
The VLCD3PE, VLCD2PE and VLCD1PE pins provide
the ability for an external LCD bias network to be used
instead of the internal ladder. Use of the VLCDxPE pins
does not prevent use of the internal ladder.
Each VLCDxPE pin has an independent control in the
LCDREFH register, allowing access to any or all of the
LCD bias signals.
This architecture allows for maximum flexibility in differ-
ent applications. The VLCDxPE pins could be used to
add capacitors to the internal reference ladder for
increasing the drive capacity. For applications where
the internal contrast control is insufficient, the firmware
can choose to enable only the VLCD3PE pin, allowing
an external contrast control circuit to use the internal
reference divider.
LCDCST<2:0>
Analog
RR RR
7 Stages
MUX
To To p o f
Reference Ladder
7
0
3
VDD
Internal Reference Contrast Control
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REGISTER 13-6: LCDREF: LCD REFERENCE LADDER CONTROL REGISTER
R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
LCDIRE — LCDCST2 LCDCST1 LCDCST0 VLCD3PE VLCD2PE VLCD1PE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 LCDIRE: LCD Internal Reference Enable bit
01 = Internal LCD reference is enabled and connected to the internal contrast control circuit
00 = Internal LCD reference is disabled
bit 6 Unimplemented: Read as ‘0’
bit 5-3 LCDCST<2:0>: LCD Contrast Control bits
Selects the Resistance of the LCD Contrast Control Resistor Ladder:
111 = Resistor ladder is at maximum resistance (minimum contrast)
110 = Resistor ladder is at 6/7th of maximum resistance
101 = Resistor ladder is at 5/7th of maximum resistance
100 = Resistor ladder is at 4/7th of maximum resistance
011 = Resistor ladder is at 3/7th of maximum resistance
010 = Resistor ladder is at 2/7th of maximum resistance
001 = Resistor ladder is at 1/7th of maximum resistance
000 = Minimum resistance (maximum contrast); resistor ladder is shorted
bit 2 VLCD3PE: Bias3 Pin Enable bit
01 = BIAS3 level is connected to the external pin, LCDBIAS3
00 = BIAS3 level is internal (internal resistor ladder)
bit 1 VLCD2PE: Bias2 Pin Enable bit
01 = BIAS2 level is connected to the external pin, LCDBIAS2
00 = BIAS2 level is internal (internal resistor ladder)
bit 0 VLCD1PE: Bias1 Pin Enable bit
01 = BIAS1 level is connected to the external pin, LCDBIAS1
00 = BIAS1 level is internal (internal resistor ladder)
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REGISTER 13-7: LCDRL: LCD REFERENCE LADDER CONTROL REGISTER LOW
R/W-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0
LRLAP1 LRLAP0 LRLBP1 LRLBP0 — LRLAT2 LRLAT1 LRLAT0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 LRLAP<1:0>: LCD Reference Ladder A Time Power Control bits
During Time Interval A:
11 = Internal LCD reference ladder is powered in High-Power mode
10 = Internal LCD reference ladder is powered in Medium Power mode
01 = Internal LCD reference ladder is powered in Low-Power mode
00 = Internal LCD reference ladder is powered down and unconnected
bit 5-4 LRLBP<1:0>: LCD Reference Ladder B Time Power Control bits
During Time Interval B:
11 = Internal LCD reference ladder is powered in High-Power mode
10 = Internal LCD reference ladder is powered in Medium Power mode
01 = Internal LCD reference ladder is powered in Low-Power mode
00 = Internal LCD reference ladder is powered down and unconnected
bit 3 Unimplemented: Read as ‘0’
bit 2-0 LRLAT<2:0>: LCD Reference Ladder A Time Interval Control bits
Sets the number of 32 clock counts when the A Time Interval Power mode is active.
For Type-A Waveforms (WFT = 0):
111 = Internal LCD reference ladder is in A Power mode for 7 clocks and B Power mode for 9 clocks
110 = Internal LCD reference ladder is in A Power mode for 6 clocks and B Power mode for 10 clocks
101 = Internal LCD reference ladder is in A Power mode for 5 clocks and B Power mode for 11 clocks
100 = Internal LCD reference ladder is in A Power mode for 4 clocks and B Power mode for 12 clocks
011 = Internal LCD reference ladder is in A Power mode for 3 clocks and B Power mode for 13 clocks
010 = Internal LCD reference ladder is in A Power mode for 2 clocks and B Power mode for 14 clocks
001 = Internal LCD reference ladder is in A Power mode for 1 clock and B Power mode for 15 clocks
000 = Internal LCD reference ladder is always in B Power mode
For Type-B Waveforms (WFT = 1):
111 = Internal LCD reference ladder is in A Power mode for 7 clocks and B Power mode for 25 clocks
110 = Internal LCD reference ladder is in A Power mode for 6 clocks and B Power mode for 26 clocks
101 = Internal LCD reference ladder is in A Power mode for 5 clocks and B Power mode for 27 clocks
100 = Internal LCD reference ladder is in A Power mode for 4 clocks and B Power mode for 28 clocks
011 = Internal LCD reference ladder is in A Power mode for 3 clocks and B Power mode for 29 clocks
010 = Internal LCD reference ladder is in A Power mode for 2 clocks and B Power mode for 30 clocks
001 = Internal LCD reference ladder is in A Power mode for 1 clock and B Power mode for 31 clocks
000 = Internal LCD reference ladder is always in B Power mode
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13.5.5 LCD BIAS GENERATION
The LCD driver module is capable of generating the
required bias voltages for LCD operation with a mini-
mum of external components. This includes the ability
to generate the different voltage levels required by the
different bias types that are required by the LCD. The
driver module can also provide bias voltages, both
above and below microcontroller VDD, through the use
of an on-chip LCD voltage regulator.
13.5.6 LCD BIAS TYPES
PIC18F97J94 family devices support three bias types,
based on the waveforms generated to control
segments and commons:
• Static (two discrete levels)
• 1/2 Bias (three discrete levels)
• 1/3 Bias (four discrete levels)
The use of different waveforms in driving the LCD is dis-
cussed in more detail in Section 13.12 “LCD Waveform
Generation”.
13.5.7 LCD VOLTAGE REGULATOR
The purpose of the LCD regulator is to provide proper
bias voltage and good contrast for the LCD, regardless
of VDD levels. This module contains a charge pump and
internal voltage reference. The regulator can be config-
ured by using external components to boost bias
voltage above VDD. It can also operate a display at a
constant voltage below VDD. The regulator can also be
selectively disabled to allow bias voltages to be
generated by an external resistor network.
The LCD regulator is controlled through the LCDREG
register. It is enabled or disabled using the
CLKSEL<1:0> bits, while the charge pump can be
selectively enabled using the CPEN bit. When the reg-
ulator is enabled, the MODE13 bit is used to select the
bias type. The peak LCD bias voltage, measured as a
difference between the potentials of LCDBIAS3 and
LCDBIAS0, is configured with the BIAS bits.
REGISTER 13-8: LCDREG: LCD VOLTAGE REGULATOR CONTROL REGISTER
R/W-0 U-0 R/W-1 R/W-1 R/W-1 R/W-1 R/W-0 R/W-0
CPEN — BIAS2 BIAS1 BIAS0 MODE13 CLKSEL1 CLKSEL 0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CPEN: LCD Charge Pump Enable bit
1 = Charge pump is enabled; highest LCD bias voltage is 3.6V
0 = Charge pump is disabled; highest LCD bias voltage is VDD
bit 6 Unimplemented: Read as ‘0’
bit 5-3 BIAS<2:0>: Regulator Voltage Output Control bits
111 = 3.60V peak (offset on LCDBIAS0 of 0V)
110 = 3.47V peak (offset on LCDBIAS0 of 0.13V)
101 = 3.34V peak (offset on LCDBIAS0 of 0.26V)
100 = 3.21V peak (offset on LCDBIAS0 of 0.39V)
011 = 3.08V peak (offset on LCDBIAS0 of 0.52V)
010 = 2.95V peak (offset on LCDBIAS0 of 0.65V)
001 = 2.82V peak (offset on LCDBIAS0 of 0.78V)
000 = 2.69V peak (offset on LCDBIAS0 of 0.91V)
bit 2 MODE13: 1/3 LCD Bias Enable bit
1 = Regulator output supports 1/3 LCD Bias mode
0 = Regulator output supports Static LCD Bias mode
bit 1-0 CLKSEL<1:0>: Regulator Clock Source Select bits
11 = 31 kHz LPRC
10 = 8 MHz FRC
01 = SOSC
00 = LCD regulator disabled
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13.6 BIAS CONFIGURATIONS
PIC18F97J94 family devices have four distinct circuit
configurations for LCD bias generation:
• M0: Regulator with Boost
• M1: Regulator without Boost
• M2: Resistor Ladder with Software Contrast
• M3: Resistor Ladder with Hardware Contrast
13.6.1 M0 (REGULATOR WITH BOOST)
In M0 operation, the LCD charge pump feature is
enabled. This allows the regulator to generate voltages
up to +3.6V to the LCD (as measured at LCDBIAS3).
M0 uses a flyback capacitor connected between
VLCAP1 and VLCAP2, as well as filter capacitors on
LCDBIAS0 through LCDBIAS3, to obtain the required
voltage boost (Figure 13-6). The output voltage (VBIAS)
is the difference of the potential between LCDBIAS3
and LCDBIAS0. It is set by the BIAS<2:0> bits which
adjust the offset between LCDBIAS0 and VSS. The
flyback capacitor (CFLY) acts as a charge storage ele-
ment for large LCD loads. This mode is useful in those
cases where the voltage requirements of the LCD are
higher than the microcontroller’s VDD. It also permits
software control of the display’s contrast, by adjust-
ment of bias voltage, by changing the value of the BIAS
bits.
M0 supports static and 1/3 bias types. Generation of
the voltage levels for 1/3 bias is handled automatically,
but must be configured in software.
M0 is enabled by selecting a valid regulator clock
source (CLKSEL<1:0> set to any value except ‘00’)
and setting the CPEN bit. If static bias type is required,
the MODE13 bit must be cleared.
13.6.2 M1 (REGULATOR WITHOUT
BOOST)
M1 operation is similar to M0, but does not use the LCD
charge pump. It can provide VBIAS up to the voltage
level supplied directly to LCDBIAS3. It can be used in
cases where VDD for the application is expected to
never drop below a level that can provide adequate
contrast for the LCD. The connection of external com-
ponents is very similar to M0, except that LCDBIAS3
must be tied directly to VDD (Figure 13-6).
The BIAS<2:0> bits can still be used to adjust contrast
in software by changing the VBIAS. As with M0, chang-
ing these bits changes the offset between LCDBIAS0
and VSS. In M1, this is reflected in the change between
the LCDBIAS0 and the voltage tied to LCDBIAS3.
Thus, if VDD should change, VBIAS will also change;
where in M0, the level of VBIAS is constant.
Like M0, M1 supports static and 1/3 bias types.
Generation of the voltage levels for 1/3 bias is handled
automatically but must be configured in software. M1 is
enabled by selecting a valid regulator clock source
(CLKSEL<1:0> set to any value except ‘00’) and clear-
ing the CPEN bit. If 1/3 bias type is required, the
MODE13 bit should also be set.
Note: When the device is put to Sleep while oper-
ating in mode M0 or M1, make sure that the
bias capacitors are fully discharged to get
the lowest Sleep current.
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DS30575A-page 260 2012 Microchip Technology Inc.
FIGURE 13-6: LCD REGULATOR CONNECTIONS FOR M0 AND M1 CONFIGURATIONS
LCDBIAS3
LCDBIAS2
LCDBIAS1
LCDBIAS0
VLCAP1
VLCAP2
C0
C1
C2
C3
C0
C1
C2
VDD
Mode 0 (VBIAS up to 3.6V) Mode 1 (VBIAS VDD)
CFLY
Note 1: These values are provided for design guidance only; they should be optimized for the application by the designer
based on the actual LCD specifications.
0.47 F(1)
0.47 F(1)
0.47 F(1)
0.47 F(1)
0.47 F(1)
0.47 F(1)
0.47 F(1)
0.47 F(1)
0.47 F(1)
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13.6.3 M2 (EXTERNAL RESISTOR LADDER
WITH SOFTWARE CONTRAST)
M2 operation also uses the LCD regulator but disables
the charge pump. The regulator’s internal voltage refer-
ence remains active as a way to regulate contrast. It is
used in cases where the current requirements of the
LCD exceed the capacity of the regulator’s charge
pump.
In this configuration, the LCD bias voltage levels are
created by an external resistor voltage divider,
connected across LCDBIAS0 through LCDBIAS3, with
the top of the divider tied to VDD (Figure 13-7). The
potential at the bottom of the ladder is determined by
the LCD regulator’s voltage reference, tied internally to
LCDBIAS0. The bias type is determined by the volt-
ages on the LCDBIAS pins, which are controlled by the
configuration of the resistor ladder. Most applications,
using M2, will use a 1/3 or 1/2 bias type. While static
bias can also be used, it offers extremely limited con-
trast range and additional current consumption over
other bias generation modes.
Like M1, the LCDBIAS bits can be used to control con-
trast, limited by the level of VDD supplied to the device.
Also, since there is no capacitor required across
VLCAP1 and VLCAP2, these pins are available as digital
I/O ports, RG2 and RG3. M2 is selected by clearing the
CLKSEL<1:0> bits and setting the CPEN bit.
FIGURE 13-7: RESISTOR LADDER CONNECTIONS FOR M2 CONFIGURATION
LCDBIAS3
Note 1: These values are provided for design guidance only; they should be optimized for the application by the designer
based on the actual LCD specifications.
Bias Level at Pin
Bias Type
1/2 Bias 1/3 Bias
LCDBIAS0 (Internal Low Reference Voltage) (Internal Low Reference Voltage)
LCDBIAS1 1/2 VBIAS 1/3 VBIAS
LCDBIAS2 1/2 VBIAS 2/3 VBIAS
LCDBIAS3 VBIAS (up to VDD)VBIAS (up to VDD)
10 k(1)
10 k(1)
1/2 Bias 1/3 Bias
LCDBIAS2
LCDBIAS1
LCDBIAS0
10 k(1)
10 k(1)
10 k(1)
VDDVDDVDD VDDVDDVDD
PIC18F97J94
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13.6.4 M3 (HARDWARE CONTRAST)
In M3, the LCD regulator is completely disabled. Like
M2, LCD bias levels are tied to VDD and are generated
using an external divider. The difference is that the
internal voltage reference is also disabled and the bot-
tom of the ladder is tied to ground (VSS); see Figure 13-
8. The value of the resistors, and the difference
between VSS and VDD, determine the contrast range;
no software adjustment is possible. This configuration
is also used where the LCD’s current requirements
exceed the capacity of the charge pump and software
contrast control is not needed.
Depending on the bias type required, resistors are con-
nected between some or all of the pins. A potentiome-
ter can also be connected between LCDBIAS3 and
VDD to allow for hardware controlled contrast adjust-
ment.
M3 is selected by clearing the CLKSEL<1:0> and
CPEN bits.
FIGURE 13-8: RESISTOR LADDER CONNECTIONS FOR M3 CONFIGURATION
LCDBIAS3
Note 1: These values are provided for design guidance only; they should be optimized for the application by the
designer based on the actual LCD specifications.
2: A potentiometer for manual contrast adjustment is optional; it may be omitted entirely.
Bias Level at Pin
Bias Type
Static 1/2 Bias 1/3 Bias
LCDBIAS0 AVSS AVSS AV SS
LCDBIAS1 AVSS 1/2 VDD 1/3 VDD
LCDBIAS2 VDD 1/2 VDD 2/3 VDD
LCDBIAS3 VDD VDD VDD
10 k(1)
10 k(1)
Static Bias 1/2 Bias 1/3 Bias
LCDBIAS2
LCDBIAS1
LCDBIAS0
10 k(1)
10 k(1)
10 k(1)
VDD
(2)
VDD VDD
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13.7 Design Considerations for the
LCD Charge Pump
When designing applications that use the LCD regula-
tor with the charge pump enabled, users must always
consider both the dynamic current and RMS (static)
current requirements of the display, and what the
charge pump can deliver. Both dynamic and static
current can be determined by Equation 13-1:
EQUATION 13-1: LCD STATIC, DYNAMIC
CURRENT
For dynamic current, C, is the value of the capacitors
attached to LCDBIAS3 and LCDBIAS2. The variable,
dV, is the voltage drop allowed on C2 and C3 during a
voltage switch on the LCD display, and dt is the duration
of the transient current after a clock pulse occurs.
For practical design purposes, it will be assumed to be
0.047 µF for C, 0.1V for dV and 1 µs for dt. This yields
a dynamic current of 4.7 mA for 1 µs.
RMS current is determined by the value of CFLY for C,
the voltage across VLCAP1 and VLCAP2 for dV and the
regulator clock period (TPER) for dt. Assuming a CFLY
value of 0.047 µF, a value of 1.02V across CFLY and
TPER of 30 µs, the maximum theoretical static current
will be 1.8 mA. Since the charge pump must charge five
capacitors, the maximum current becomes 360 µA.
For a real-world assumption of 50% efficiency, this
yields a practical current of 180 µA. Users should com-
pare the calculated current capacity against the
requirements of the LCD. While dV and dt are relatively
fixed by device design, the values of CFLY and the
capacitors on the LCDBIAS pins can be changed to
increase or decrease current. As always, any changes
should be evaluated in the actual circuit for their impact
on the application.
I = C x dV
dt
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13.8 LCD Multiplex Types
The LCD driver module can be configured into four
multiplex types:
• Static (only COM0 used)
• 1/2 multiplex (COM0 and COM1 are used)
• 1/3 multiplex (COM0, COM1 and COM2 are used)
• 1/4 multiplex (COM0, COM1, COM2 and COM3
are used)
• 1/5 multiplex (COM0, COM1, COM2, COM3 and
COM4 are used)
• 1/6 multiplex (COM0, COM1, COM2, COM3,
COM4 and COM5 are used)
• 1/7 multiplex (COM0, COM1, COM2, COM3,
COM4, COM5 and COM6 are used)
• 1/8 multiplex (COM0, COM1, COM2, COM3,
COM4, COM5, COM6 and COM7 are used)
The LMUX<2:0> setting (LCDCON<2:0>) decides the
function of the COM pins. (For details, see Table 1 3-4).
If the pin is a digital I/O, the corresponding TRIS bit
controls the data direction. If the pin is a COM drive, the
TRIS setting of that pin is overridden.
13.9 Segment Enables
The LCDSEx registers are used to select the pin function
for each segment pin. The selection allows each pin to
operate as either an LCD segment driver or a digital only
pin. To configure the pin as a segment pin, the corre-
sponding bits in the LCDSEx registers must be set to ‘1’.
If the pin is a digital I/O, the corresponding TRIS bit
controls the data direction. Any bit set in the LCDSEx
registers overrides any bit settings in the corresponding
TRIS register.
13.10 Pixel Control
The LCDDATAx registers contain bits that define the
state of each pixel. Each bit defines one unique pixel.
Table 13-2 shows the correlation of each bit in the
LCDDATAx registers to the respective common and
segment signals.
Any LCD pixel location not being used for display can
be used as general purpose RAM.
13.11 LCD Frame Frequency
The rate at which the COM and SEG outputs change is
called the LCD frame frequency.
Note: On a Power-on Reset, the LMUX<2:0>
bits are ‘000’.
TABLE 13-4: COM<7:0> PIN FUNCTIONS
LMUX<2:0> COM7 Pin COM6 Pin COM5 Pin COM4 Pin COM3 Pin COM2 Pin COM1 Pin COM0 Pin
111 COM7 COM6 COM5 COM4 COM3 COM2 COM1 COM0
110 I/O Pin COM6 COM5 COM4 COM3 COM2 COM1 COM0
101 I/O Pin I/O Pin COM5 COM4 COM3 COM2 COM1 COM0
100 I/O Pin I/O Pin I/O Pin COM4 COM3 COM2 COM1 COM0
011 I/O Pin I/O Pin I/O Pin I/O Pin COM3 COM2 COM1 COM0
010 I/O Pin I/O Pin I/O Pin I/O Pin I/O Pin COM2 COM1 COM0
001 I/O Pin I/O Pin I/O Pin I/O Pin I/O Pin I/O Pin COM1 COM0
000 I/O Pin I/O Pin I/O Pin I/O Pin I/O Pin I/O Pin I/O Pin COM0
Note: Pins, COM<7:4>, can also be used as SEG pins when ¼ multiplex to static multiplex are used. These pins
can be used as I/O pins only if respective bits in the LCDSEx registers are set to ‘0’.
Note: On a Power-on Reset, these pins are
configured as digital I/O.
TABLE 13-5: FRAME FREQUENCY FORMULAS
Multiplex Frame Frequency =
Static (‘000’) Clock Source/(4 x 1 x (LP<3:0> + 1))
1/2 (‘001’) Clock Source/(2 x 2 x (LP<3:0> + 1))
1/3 (‘010’) Clock Source/(1 x 3 x (LP<3:0> + 1))
1/4 (‘011’) Clock Source/(1 x 4 x (LP<3:0> + 1))
1/5 (‘100’) Clock Source/(1 x 5 x (LP<3:0> + 1))
1/6 (‘101’) Clock Source/(1 x 6 x (LP<3:0> + 1))
1/7 (‘110’) Clock Source/(1 x 7 x (LP<3:0> + 1))
1/8 (‘111’) Clock Source/(1 x 8 x (LP<3:0> + 1))
Note: The clock source is FRC/8192, SOSC/32 or LPRC/32.
2012 Microchip Technology Inc. DS30575A-page 265
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13.12 LCD Waveform Generation
LCD waveform generation is based on the philosophy
that the net AC voltage across the dark pixel should be
maximized and the net AC voltage across the clear
pixel should be minimized. The net DC voltage across
any pixel should be zero.
The COM signal represents the time slice for each
common, while the SEG contains the pixel data.
The pixel signal (COM-SEG) will have no DC compo-
nent and can take only one of the two rms values. The
higher rms value will create a dark pixel and a lower
rms value will create a clear pixel.
As the number of commons increases, the delta
between the two rms values decreases. The delta rep-
resents the maximum contrast that the display can
have.
The LCDs can be driven by two types of waveforms:
Type-A and Type-B. In a Type-A waveform, the phase
changes within each common type, whereas a Type-B
waveform’s phase changes on each frame boundary.
Thus, Type-A waveforms maintain 0 VDC over a single
frame, whereas Type-B waveforms take two frames.
Figure 13-9 through Figure 13-21 provide waveforms
for static, half-multiplex, one-third multiplex and quarter
multiplex drives for Type-A and Type-B waveforms.
FIGURE 13-9: TYPE-A/TYPE-B WAVEFORMS IN STATIC DRIVE
Note: If Sleep has to be executed with LCD Sleep
enabled (SLPEN (LCDCON<6>) = 1),
care must be taken to execute Sleep only
when VDC on all the pixels is ‘0’.
V1
V0
COM0
SEG0
COM0-SEG0
COM0-SEG1
SEG1
V1
V0
V1
V0
V0
V1
-V1
V0
1 Frame
COM0
SEG0
SEG1
SEG2
SEG3
SEG4
SEG5
SEG6
SEG7
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FIGURE 13-10: TYPE-A WAVEFORMS IN 1/2 MUX, 1/2 BIAS DRIVE
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
-V2
-V1
V2
V1
V0
-V2
-V1
COM0
COM1
SEG0
SEG1
COM0-SEG0
COM0-SEG1
1 Frame
COM1
COM0
SEG0
SEG1
SEG2
SEG3
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FIGURE 13-11: TYPE-B WAVEFORMS IN 1/2 MUX, 1/2 BIAS DRIVE
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
-V2
-V1
V2
V1
V0
-V2
-V1
COM0
COM1
SEG0
SEG1
COM0-SEG0
COM0-SEG1
COM1
COM0
SEG0
SEG1
SEG2
SEG3
2 Frames
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FIGURE 13-12: TYPE-A WAVEFORMS IN 1/2 MUX, 1/3 BIAS DRIVE
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
-V3
-V2
-V1
V3
V2
V1
V0
-V3
-V2
-V1
COM0
COM1
SEG0
SEG1
COM0-SEG0
COM0-SEG1
1 Frame
COM1
COM0
SEG0
SEG1
SEG2
SEG3
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FIGURE 13-13: TYPE-B WAVEFORMS IN 1/2 MUX, 1/3 BIAS DRIVE
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
-V3
-V2
-V1
V3
V2
V1
V0
-V3
-V2
-V1
COM0
COM1
SEG0
SEG1
COM0-SEG0
COM0-SEG1
COM1
COM0
SEG0
SEG1
SEG2
SEG3
2 Frames
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FIGURE 13-14: TYPE-A WAVEFORMS IN 1/3 MUX, 1/2 BIAS DRIVE
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
-V2
-V1
V2
V1
V0
-V2
-V1
COM0
COM1
COM2
SEG0
SEG1
COM0-SEG0
COM0-SEG1
1 Frame
COM2
COM1
COM0
SEG0
SEG1
SEG2
SEG2
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FIGURE 13-15: TYPE-B WAVEFORMS IN 1/3 MUX, 1/2 BIAS DRIVE
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
V2
V1
V0
-V2
-V1
V2
V1
V0
-V2
-V1
COM0
COM1
COM2
SEG0
SEG1
COM0-SEG0
COM0-SEG1
2 Frames
COM2
COM1
COM0
SEG0
SEG1
SEG2
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FIGURE 13-16: TYPE-A WAVEFORMS IN 1/3 MUX, 1/3 BIAS DRIVE
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
-V3
-V2
-V1
V3
V2
V1
V0
-V3
-V2
-V1
COM0
COM1
COM2
SEG0
SEG1
COM0-SEG0
COM0-SEG1
1 Frame
COM2
COM1
COM0
SEG0
SEG1
SEG2
SEG2
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FIGURE 13-17: TYPE-B WAVEFORMS IN 1/3 MUX, 1/3 BIAS DRIVE
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
-V3
-V2
-V1
V3
V2
V1
V0
-V3
-V2
-V1
COM0
COM1
COM2
SEG0
SEG1
COM0-SEG0
COM0-SEG1
2 Frames
COM2
COM1
COM0
SEG0
SEG1
SEG2
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FIGURE 13-18: TYPE-A WAVEFORMS IN 1/4 MUX, 1/3 BIAS DRIVE
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
-V3
-V2
-V1
V3
V2
V1
V0
-V3
-V2
-V1
COM0
COM1
COM2
COM3
SEG0
SEG1
COM0-SEG0
COM0-SEG1
COM3
COM2
COM1
COM0
1 Frame
SEG0
SEG1
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FIGURE 13-19: TYPE-B WAVEFORMS IN 1/4 MUX, 1/3 BIAS DRIVE
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
-V3
-V2
-V1
V3
V2
V1
V0
-V3
-V2
-V1
COM0
COM1
COM2
COM3
SEG0
SEG1
COM0-SEG0
COM0-SEG1
COM3
COM2
COM1
COM0
2 Frames
SEG0
SEG1
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FIGURE 13-20: TYPE-A WAVEFORMS IN 1/8 MUX, 1/3 BIAS DRIVE
COM4
COM3
COM2
COM1
SEG0
COM5
COM7
COM6
COM0
COM0
COM1
COM2
COM7
SEG0
COM0-SEG0
COM1-SEG0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
-V3
-V2
-V1
V3
V2
V1
V0
-V3
-V2
-V1
V3
V2
V1
V0
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FIGURE 13-21: TYPE-B WAVEFORMS IN 1/8 MUX, 1/3 BIAS DRIVE
COM4
COM3
COM2
COM1
SEG0
COM5
COM7
COM6
COM0
V3
V2
COM0
V1
V0
V3
V2
V1
COM1 V0
V3
V2
V1
COM2 V0
V3
V2
V1
COM7 V0
V3
V2
SEG0 V1
V0
V3
V2
V1
V0
COM0 - SEG0
-V1
-V2
-V3
V3
V2
V1
V0
COM1 - SEG0
-V1
-V2
-V3
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13.13 LCD Interrupts
The LCD timing generation provides an interrupt that
defines the LCD frame timing. This interrupt can be
used to coordinate the writing of the pixel data with the
start of a new frame, which produces a visually crisp
transition of the image.
This interrupt can also be used to synchronize external
events to the LCD. For example, the interface to an
external segment driver can be synchronized for
segment data updates to the LCD frame.
A new frame is defined as beginning at the leading
edge of the COM0 common signal. The interrupt will be
set immediately after the LCD controller completes
accessing all pixel data required for a frame. This will
occur at a fixed interval before the frame boundary
(TFINT), as shown in Figure 13-22.
The LCD controller will begin to access data for the
next frame within the interval from the interrupt to when
the controller begins accessing data after the interrupt
(TFWR). New data must be written within TFWR, as this
is when the LCD controller will begin to access the data
for the next frame.
When the LCD driver is running with Type-B wave-
forms, and the LMUX<2:0> bits are not equal to ‘000’,
there are some additional issues.
Since the DC voltage on the pixel takes two frames to
maintain 0V, the pixel data must not change between
subsequent frames. If the pixel data were allowed to
change, the waveform for the odd frames would not
necessarily be the complement of the waveform gener-
ated in the even frames and a DC component would be
introduced into the panel.
Because of this, using Type-B waveforms requires
synchronizing the LCD pixel updates to occur within a
subframe after the frame interrupt.
To correctly sequence writing in Type-B, the interrupt
only occurs on complete phase intervals. If the user
attempts to write when the write is disabled, the WERR
bit (LCDCON<5>) is set.
FIGURE 13-22: EXAMPLE WAVEFORMS AND INTERRUPT TIMING IN QUARTER
DUTY CYCLE DRIVE
Note: The interrupt is not generated when the
Type-A waveform is selected and when
the Type-B with no multiplex (static) is
selected.
Frame
Boundary
Frame
Boundary
LCD
Interrupt
Occurs
Controller Accesses
Next Frame Data
TFINT
TFWR
TFWR =TFRAME/2 * (LMUX<2:0> + 1) + TCY/2
TFINT =(TFWR/2 – (2 TCY + 40 ns)) Minimum = 1.5(TFRAME/4) – (2 TCY + 40 ns)
(TFWR/2 – (1 TCY + 40 ns)) Maximum = 1.5(TFRAME/4) – (1 TCY + 40 ns)
Frame
Boundary
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
COM0
COM1
COM2
COM3
2 Frames
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13.14 Configuring the LCD Module
To configure the LCD module.
1. Select the frame clock prescale using bits,
LP<3:0> (LCDPS<3:0>).
2. Configure the appropriate pins to function as
segment drivers using the LCDSEx registers.
3. If using the internal reference resistors for
biasing, enable the internal reference ladder
and:
• Define the Mode A and Mode B interval by
using the LRLAT<2:0> bits (LCDREFL<2:0>)
• Define the low, medium or high ladder for
Mode A and Mode B by using the
LRLAP<1:0> bits (LCDREFL<7:6>) and the
LRLBP<1:0> bits (LCDREFL<5:4>),
respectively
• Set the VLCDxPE bits and enable the
LCDIRE bit (LCDREFH<7>)
4. Configure the following LCD module functions
using the LCDCONL register:
• Multiplex and Bias mode – LMUX<2:0> bits
• Timing Source – CS<1:0> bits
• Sleep mode – SLPEN bit
5. Write initial values to the Pixel Data registers,
LCDDATA0 through LCDDATA63.
6. Clear the LCD Interrupt Flag, LCDIF, and if
desired, enable the interrupt by setting bit,
LCDIE.
7. Enable the LCD module by setting the ON bit
(LCDCONL<7>)
13.15 Operation During Sleep
The LCD module can operate during Sleep. The selec-
tion is controlled by the SLPEN bit (LCDCONL<6>).
Setting the SLPEN bit allows the LCD module to go to
Sleep. Clearing the SLPEN bit allows the module to
continue to operate during Sleep.
If a SLEEP instruction is executed and SLPEN = 1, the
LCD module will cease all functions and go into a very
Low-Current Consumption mode. The module will stop
operation immediately and drive the minimum LCD volt-
age on both segment and common lines. Figure 13-23
shows this operation.
The LCD module current consumption will not
decrease in this mode, but the overall consumption of
the device will be lower due to shut down of the core
and other peripheral functions.
To ensure that no DC component is introduced on the
panel, the SLEEP instruction should be executed imme-
diately after an LCD frame boundary. The LCD interrupt
can be used to determine the frame boundary. See
Section 13.13 “LCD Interrupts” for the formulas to
calculate the delay.
If a SLEEP instruction is executed and SLPEN = 0, the
module will continue to display the current contents of
the LCDDATA registers. The LCD data cannot be
changed.
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FIGURE 13-23: SLEEP ENTRY/EXIT WHEN SLPEN = 1 OR CS<1:0> = 00.
SLEEP Instruction Execution Wake-up
2 Frames
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
V3
V2
V1
V0
COM0
COM1
COM2
SEG0
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14.0 TIMER0 MODULE
The Timer0 module incorporates the following features:
• Software-selectable operation as a timer or
counter in both 8-bit or 16-bit modes
• Readable and writable registers
• Dedicated 8-bit, software programmable
prescaler
• Selectable clock source (internal or external)
• Edge select for external clock
• Interrupt-on-overflow
The T0CON register (Register 14-1) controls all
aspects of the module’s operation, including the
prescale selection. It is both readable and writable.
Figure 14-1 provides a simplified block diagram of the
Timer0 module in 8-bit mode. Figure 14-2 provides a
simplified block diagram of the Timer0 module in 16-bit
mode.
REGISTER 14-1: T0CON: TIMER0 CONTROL REGISTER
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
TMR0ON T08BIT T0CS1 T0CS0 PSA T0PS2 T0PS1 T0PS0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 TMR0ON: Timer0 On/Off Control bit
1 = Enables Timer0
0 = Stops Timer0
bit 6 T08BIT: Timer0 8-Bit/16-Bit Control bit
1 = Timer0 is configured as an 8-bit timer/counter
0 = Timer0 is configured as a 16-bit timer/counter
bit 5-4 T0CS<1:0>: Timer0 Clock Source Select bit
11 = Increment on high-to-low transition on T0CKI pin
10 = Increment on low-to-high transition on T0CKI pin
01 = Internal clock (FOSC/4)
00 = INTOSC
bit 3 PSA: Timer0 Prescaler Assignment bit
1 = Timer0 prescaler is not assigned; Timer0 clock input bypasses prescaler
0 = Timer0 prescaler is assigned; Timer0 clock input comes from prescaler output
bit 2-0 T0PS<2:0>: Timer0 Prescaler Select bits
111 = 1:256 Prescale value
110 = 1:128 Prescale value
101 = 1:64 Prescale value
100 = 1:32 Prescale value
011 = 1:16 Prescale value
010 = 1:8 Prescale value
001 = 1:4 Prescale value
000 = 1:2 Prescale value
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14.1 Timer0 Operation
Timer0 can operate in one of these two modes:
• As an 8-bit (T08BIT = 1) or 16-bit (T08BIT = 0)
timer
• As an asynchronous 8-bit (T08BIT = 1) or 16-bit
(T08BIT = 0) counter
14.1.1 TIMER MODE
In Timer mode, Timer0 either increments every CPU
clock cycle, or every instruction cycle, depending on
the clock select bit, TMR0CS<1:0> (T0CON<7:6>).
14.1.2 COUNTER MODE
In this mode, Timer0 is incremented via a rising or fall-
ing edge of an external source on the T0CKI pin. The
clock select bits, TMR0CS<1:0>, must be set to ‘1x’.
14.2 Timer0 Reads and Writes in 16-Bit
Mode
TMR0H is not the actual high byte of Timer0 in 16-bit
mode. It is actually a buffered version of the real high
byte of Timer0, which is not directly readable nor
writable (see Figure 14-2). TMR0H is updated with the
contents of the high byte of Timer0 during a read of
TMR0L. This provides the ability to read all 16 bits of
Timer0 without having to verify that the read of the high
and low byte were valid, due to a rollover between
successive reads of the high and low byte.
Similarly, a write to the high byte of Timer0 must also
take place through the TMR0H Buffer register. The high
byte is updated with the contents of TMR0H when a
write occurs to TMR0L. This allows all 16 bits of Timer0
to be updated at once.
FIGURE 14-1: TIMER0 BLOCK DIAGRAM (8-BIT MODE)
FIGURE 14-2: TIMER0 BLOCK DIAGRAM (16-BIT MODE)
Note: Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
T0CKI Pin
T0SE
0
1
1
0
T0CS
FOSC/4
Sync with
Internal
Clocks
TMR0L
(2 TCY Delay)
Internal Data Bus
PSA
T0PS<2:0>
Set
TMR0IF
on Overflow
38
8
Programmable
Prescaler
Note: Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
T0CKI Pin
T0SE
0
1
1
0
T0CS
FOSC/4
Sync with
Internal
Clocks
TMR0L
(2 TCY Delay)
Internal Data Bus
8
PSA
T0PS<2:0>
Set
TMR0IF
on Overflow
3
TMR0
TMR0H
High Byte
88
8
Read TMR0L
Write TMR0L
8
Programmable
Prescaler
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14.3 Prescaler
An 8-bit counter is available as a prescaler for the Timer0
module. The prescaler is not directly readable or writable.
Its value is set by the PSA and T0PS<2:0> bits
(T0CON<3:0>), which determine the prescaler
assignment and prescale ratio.
Clearing the PSA bit assigns the prescaler to the
Timer0 module. When it is assigned, prescale values
from 1:2 through 1:256 in power-of-two increments are
selectable.
When assigned to the Timer0 module, all instructions
writing to the TMR0 register (for example, CLRF TMR0,
MOVWF TMR0, BSF TMR0) clear the prescaler count.
14.3.1 SWITCHING PRESCALER
ASSIGNMENT
The prescaler assignment is fully under software
control and can be changed “on-the-fly” during program
execution.
14.4 Timer0 Interrupt
The TMR0 interrupt is generated when the TMR0
register overflows from FFh to 00h in 8-bit mode, or
from FFFFh to 0000h in 16-bit mode. This overflow sets
the TMR0IF flag bit. The interrupt can be masked by
clearing the TMR0IE bit (INTCON<5>). Before re-
enabling the interrupt, the TMR0IF bit must be cleared
in software by the Interrupt Service Routine (ISR).
Since Timer0 is shutdown in Sleep mode, the TMR0
interrupt cannot awaken the processor from Sleep.
Note: Writing to TMR0 when the prescaler is
assigned to Timer0 will clear the prescaler
count but will not change the prescaler
assignment.
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15.0 TIMER1/3/5 MODULES
The Timer1/3/5 timer/counter modules incorporate
these features:
• Software-selectable operation as a 16-bit timer or
counter
• Readable and writable eight-bit registers (TMRxH
and TMRxL)
• Selectable clock source (internal or external) with
device clock or SOSC Oscillator internal options
• Interrupt-on-overflow
• Module Reset on ECCP Special Event Trigger
A simplified block diagram of the Timer1/3/5 module is
shown in Figure 15-1.
The Timer1/3/5 module is controlled through the
TxCON register (Register 15-1). It also selects the
clock source options for the ECCP modules. (For more
information, see Section 18.1.1 “ECCP Module and
Timer Resources”).
The FOSC clock source should not be used with the
ECCP capture/compare features. If the timer will be
used with the capture or compare features, always
select one of the other timer clocking options.
Note: Throughout this section, generic references
are used for register and bit names that are the
same – except for an ‘x’ variable that indicates
the item’s association with the Timer1, Timer3
or Timer5 module. For example, the control
register is named TxCON and refers to
T1CON, T3CON and T5CON.
2012 Microchip Technology Inc. DS30575A-page 285
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REGISTER 15-1: TxCON: TIMERx CONTROL REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
TMRxCS1 TMRxCS0 TxCKPS1 TxCKPS0 SOSCEN TxSYNC RD16 TMRxON
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 TMRxCS<1:0>: Timerx Clock Source Select bits
11 = Timerx Clock source is INTOSC
10 = Timerx clock source depends on the SOSCEN bit:
SOSCEN = 0:
External clock from the TxCKI pin (on the rising edge).
SOSCEN = 1:
Depending on the SOSCSEL fuses, either a crystal oscillator on the SOSCI/SOSCO pins or an external
clock from the SCLKI pin.
01 = Timerx clock source is the system clock (FOSC)(1)
00 = Timerx clock source is the instruction clock (FOSC/4)
bit 5-4 TxCKPS<1:0>: Timerx Input Clock Prescale Select bits
11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value
bit 3 SOSCEN: SOSC Oscillator Enable bit
1 = SOSC/SCLKI are enabled for Timerx (based on the SOSCSEL fuses)
0 = SOSC/SCLKI are disabled for Timerx and TxCKI is enabled
bit 2 TxSYNC: Timerx External Clock Input Synchronization Control bit
(Not usable if the device clock comes from Timer1/3/5.)
When TMRxCS<1:0> = 10:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMRxCS<1:0> = 0x:
This bit is ignored; Timer1/3/5 uses the internal clock.
bit 1 RD16: 16-Bit Read/Write Mode Enable bit
1 = Enables register read/write of Timerx in one 16-bit operation
0 = Enables register read/write of Timerx in two eight-bit operations
bit 0 TMRxON: Timerx On bit
1 = Enables Timerx
0 = Stops Timerx
Note 1: The FOSC clock source should not be selected if the timer will be used with the ECCP capture/compare
features.
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DS30575A-page 286 2012 Microchip Technology Inc.
15.1 Timer1/3/5 Gate Control Register
The Timer1/3/5 Gate Control register (TxGCON),
provided in Register 15-2, is used to control the Timerx
gate.
REGISTER 15-2: TxGCON: TIMERx GATE CONTROL REGISTER(1)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R-x R/W-0 R/W-0
TMRxGE TxGPOL TxGTM TxGSPM
TxGGO/TxDONE
TxGVAL TxGSS1 TxGSS0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 TMRxGE: Timerx Gate Enable bit
If TMRxON = 0:
This bit is ignored.
If TMRxON = 1:
1 = Timerx counting is controlled by the Timerx gate function
0 = Timerx counts regardless of Timerx gate function
bit 6 TxGPOL: Timerx Gate Polarity bit
1 = Timerx gate is active-high (Timerx counts when gate is high)
0 = Timerx gate is active-low (Timerx counts when gate is low)
bit 5 TxGTM: Timerx Gate Toggle Mode bit
1 = Timerx Gate Toggle mode is enabled.
0 = Timerx Gate Toggle mode is disabled and toggle flip-flop is cleared
Timerx gate flip-flop toggles on every rising edge.
bit 4 TxGSPM: Timerx Gate Single Pulse Mode bit
1 = Timerx Gate Single Pulse mode is enabled and is controlling Timerx gate
0 = Timerx Gate Single Pulse mode is disabled
bit 3 TxGGO/TxDONE: Timerx Gate Single Pulse Acquisition Status bit
1 = Timerx gate single pulse acquisition is ready, waiting for an edge
0 = Timerx gate single pulse acquisition has completed or has not been started
This bit is automatically cleared when TxGSPM is cleared.
bit 2 TxGVAL: Timerx Gate Current State bit
Indicates the current state of the Timerx gate that could be provided to TMRxH:TMRxL; unaffected by the
Timerx Gate Enable (TMRxGE) bit.
bit 1-0 TxGSS<1:0>: Timerx Gate Source Select bits
11 = Comparator 2 output
10 = Comparator 1 output
01 = TMR(x+1) to match PR(x+1) output(2)
00 = Timer1 gate pin
The Watchdog Timer Oscillator is turned on if TMRxGE = 1, regardless of the state of TMRxON.
Note 1: Programming the TxGCON prior to TxCON is recommended.
2: Timer(x+1) will be Timer1/3/5 for Timerx (Timer1/3/5), respectively.
2012 Microchip Technology Inc. DS30575A-page 287
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15.2 Timer1/3/5 Operation
Timer1, Timer3 and Timer5 can operate in these
modes:
•Timer
• Synchronous Counter
• Asynchronous Counter
• Timer with Gated Control
The operating mode is determined by the clock select
bits, TMRxCSx (TxCON<7:6>). When the TMRxCSx bits
are cleared (= 00), Timer1/3/5 increments on every inter-
nal instruction cycle (FOSC/4). When TMRxCSx = 01, the
Timer1/3/5 clock source is the system clock (FOSC).
When it is ‘10’, Timer1/3/5 works as a counter from the
external clock from the TxCKI pin (on the rising edge after
the first falling edge) or the SOSC Oscillator. When it is
‘11’, the Timer1/3/5 clock source is INTOSC.
FIGURE 15-1: TIMER1/3/5 BLOCK DIAGRAM
TMR3H TMR3L
T3SYNC
T3CKPS<1:0>
0
1
Synchronized
Clock Input
2
Set Flag bit
TMR3IF on
Overflow TMR3(2)
TMR3ON
Note 1: ST buffer is a high-speed type when using T3CKI.
2: Timer3 registers increment on the rising edge.
3: Synchronization does not operate while in Sleep.
4: The output of SOSC is determined by the SOSCSEL Configuration bits.
T3G
SOSC
FOSC/4
Internal
Clock
SOSCO/SCLKI
SOSCI
1
0
T3CKI
TMR3CS<1:0>
(1)
Synchronize(3)
det
Sleep Input
TMR3GE
0
1
00
01
10
11
From TMR4
T3GPOL
D
Q
CK
Q
0
1
T3GVAL
T3GTM
T3GSPM
T3GGO/
T3GSS<1:0>
EN
OUT(4)
10
00
01
FOSC
Internal
Clock
From Comparator 2
Match PR4
R
Q1
RD
T3GCON
Data Bus
Interrupt
TMR3GIF
Set
T3CLK
FOSC/2
Internal
Clock
D
EN
Q
T3G_IN
TMR3ON
Output
01
Timer3 Clock
is INTOSC
Single Pulse
Acq. Control
T3DONE
Prescaler
1, 2, 4, 8
From Comparator 1
Output
T1CON.SOSCEN
T1CON.SOSCEN
SOSCGO
NOSC<2:0> = 100
D
EN
Q
det
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DS30575A-page 288 2012 Microchip Technology Inc.
15.3 Timer1/3/5 16-Bit Read/Write Mode
Timer1/3/5 can be configured for 16-bit reads and
writes (see Figure 15-3). When the RD16 control bit
(TxCON<1>) is set, the address for TMRxH is mapped
to a buffer register for the high byte of Timer1/3/5. A
read from TMRxL will load the contents of the high byte
of Timer1/3/5 into the Timerx High Byte Buffer register.
This provides users with the ability to accurately read
all 16 bits of Timer1/3/5 without having to determine
whether a read of the high byte, followed by a read of
the low byte, has become invalid due to a rollover
between reads.
A write to the high byte of Timer1/3/5 must also take
place through the TMRxH Buffer register. The
Timer1/3/5 high byte is updated with the contents of
TMRxH when a write occurs to TMRxL. This allows
users to write all 16 bits to both the high and low
bytes of Timer1/3/5 at once.
The high byte of Timer1/3/5 is not directly readable or
writable in this mode. All reads and writes must take
place through the Timerx High Byte Buffer register.
Writes to TMRxH do not clear the Timer1/3/5 prescaler.
The prescaler is only cleared on writes to TMRxL.
15.4 Using the SOSC Oscillator as the
Timer1/3/5 Clock Source
The SOSC Internal Oscillator may be used as the clock
source for Timer1/3/5. It can be enabled in one of these
ways:
• Setting the SOSCEN bit in either of the TxCON
registers (TxCON<3>)
• Setting the SOSCGO bit in the OSCCON2
register (OSCCON2<1>)
• Setting the NOSC bits to secondary clock source
in the OSCCON register (OSCCON<2:0> = 100)
The SOSCGO bit is used to warm up the SOSC so that
it is ready before any peripheral requests it.
To use it as the Timer3 clock source, the TMR3CSx bits
must also be set. As previously noted, this also config-
ures Timer3 to increment on every rising edge of the
oscillator source.
The SOSC Oscillator is described in Section 15.4
“Using the SOSC Oscillator as the Timer1/3/5 Clock
Source”.
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15.5 Timer1/3/5 Gates
Timer1/3/5 can be configured to count freely or the count
can be enabled and disabled using the Timer1/3/5 gate
circuitry. This is also referred to as the Timer1/3/5 gate
count enable.
The Timer1/3/5 gate can also be driven by multiple
selectable sources.
15.5.1 TIMER1/3/5 GATE COUNT ENABLE
The Timerx Gate Enable mode is enabled by setting
the TMRxGE bit (TxGCON<7>). The polarity of the
Timerx Gate Enable mode is configured using the
TxGPOL bit (TxGCON<6>).
When Timerx Gate Enable mode is enabled, Timer1/3/5
will increment on the rising edge of the Timer1/3/5 clock
source. When Timerx Gate Enable mode is disabled, no
incrementing will occur and Timer1/3/5 will hold the
current count. See Figure 15-2 for timing details.
TABLE 15-1: TIMER1/3/5 GATE ENABLE
SELECTIONS
FIGURE 15-2: TIMER1/3/5 GATE COUNT ENABLE MODE
TxCLK(†)TxGPOL
(TxGCON<6>) TxG Pin Timerx
Operation
00Counts
01Holds Count
10Holds Count
11Counts
† The clock on which TMR1/3/5 is running. For
more information, see TxCLK in Figure 15-1.
TMRxGE
TxGPOL
TxG_IN
TxCKI
TxGVAL
Timer1/3/5 N N + 1 N + 2 N + 3 N + 4
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15.5.2 TIMER1/3/5 GATE SOURCE
SELECTION
The Timer1/3/5 gate source can be selected from one
of four different sources. Source selection is controlled
by the TxGSS<1:0> bits (TxGCON<1:0>). The polarity
for each available source is also selectable and is
controlled by the TxGPOL bit (TxGCON <6>).
TABLE 15-2: TIMER1/3/5 GATE SOURCES
15.5.2.1 TxG Pin Gate Operation
The TxG pin is one source for Timer1/3/5 gate control. It
can be used to supply an external source to the Timerx
gate circuitry.
15.5.2.2 Timer2/4/6/8 Match Gate Operation
The TMR(x+1) register will increment until it matches the
value in the PR(x+1) register. On the very next increment
cycle, TMR2 will be reset to 00h. When this Reset
occurs, a low-to-high pulse will automatically be gener-
ated and internally supplied to the Timerx gate circuitry.
The pulse will remain high for one instruction cycle and
will return back to a low state until the next match.
Depending on TxGPOL, Timerx increments differently
when TMR(x+1) matches PR(x+1). When
TxGPOL = 1, Timerx increments for a single instruction
cycle following a TMR(x+1) match with PR(x+1). When
TxGPOL = 0, Timerx increments continuously, except
for the cycle following the match, when the gate signal
goes from low-to-high.
15.5.2.3 Comparator 1 Output Gate Operation
The output of Comparator1 can be internally supplied
to the Timerx gate circuitry. After setting up
Comparator 1 with the CM1CON register, Timerx will
increment depending on the transitions of the C1OUT
(CMSTAT<0>) bit.
15.5.2.4 Comparator 2 Output Gate Operation
The output of Comparator 2 can be internally supplied
to the Timerx gate circuitry. After setting up
Comparator 2 with the CM2CON register, Timerx will
increment depending on the transitions of the C2OUT
(CMSTAT<1>) bit.
15.5.3 TIMER1/3/5 GATE TOGGLE MODE
When Timer1/3/5 Gate Toggle mode is enabled, it is pos-
sible to measure the full cycle length of a Timer1/3/5 gate
signal, as opposed to the duration of a single level pulse.
The Timerx gate source is routed through a flip-flop that
changes state on every incrementing edge of the
signal. (For timing details, see Figure 15-3.)
The TxGVAL bit will indicate when the Toggled mode is
active and the timer is counting.
Timer1/3/5 Gate Toggle mode is enabled by setting the
TxGTM bit (TxGCON<5>). When the TxGTM bit is
cleared, the flip-flop is cleared and held clear. This is
necessary in order to control which edge is measured.
FIGURE 15-3: TIMER1/3/5 GATE TOGGLE MODE
TxGSS<1:0> Timerx Gate Source
00 Timerx Gate Pin
01 TMR(x+1) to Match PR(x+1)
(TMR(x+1) increments to match
PR(x+1))
10 Comparator 1 Output
(comparator logic high output)
11 Comparator 2 Output
(comparator logic high output)
TMRxGE
TxGPOL
TxGTM
TxG_IN
TxCKI
TxGVAL
Timer1/3/5 N N + 1 N + 2 N + 3 N + 4 N + 5 N + 6 N + 7 N + 8
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15.5.4 TIMER1/3/5 GATE SINGLE PULSE
MODE
When Timer1/3/5 Gate Single Pulse mode is enabled,
it is possible to capture a single pulse gate event.
Timer1/3/5 Gate Single Pulse mode is first enabled by
setting the TxGSPM bit (TxGCON<4>). Next, the
TxGGO/TxDONE bit (TxGCON<3>) must be set.
The Timer1/3/5 will be fully enabled on the next incre-
menting edge. On the next trailing edge of the pulse,
the TxGGO/TxDONE bit will automatically be cleared.
No other gate events will be allowed to increment
Timer1/3/5 until the TxGGO/TxDONE bit is once again
set in software.
Clearing the TxGSPM bit also will clear the TxGGO/
TxDONE bit. (For timing details, see Figure 15-4.)
Simultaneously enabling the Toggle mode and the
Single Pulse mode will permit both sections to work
together. This allows the cycle times on the Timer1/3/5
gate source to be measured. (For timing details, see
Figure 15-5.)
FIGURE 15-4: TIMER1/3/5 GATE SINGLE PULSE MODE
TMRxGE
TxGPOL
TxG_IN
TxCKI
TxGVAL
Timer1/3/5 N N + 1 N + 2
TxGSPM
TxGGO/
TxDONE
Set by Software
Cleared by Hardware on
Falling Edge of TxGVAL
Set by Hardware on
Falling Edge of TxGVAL
Cleared by Software
Cleared by
Software
TMRxGIF
Counting Enabled on
Rising Edge of TxG
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FIGURE 15-5: TIMER1/3/5 GATE SINGLE PULSE AND TOGGLE COMBINED MODE
15.5.5 TIMER1/3/5 GATE VALUE STATUS
When Timer1/3/5 gate value status is utilized, it is
possible to read the most current level of the gate con-
trol value. The value is stored in the TxGVAL bit
(TxGCON<2>). The TxGVAL bit is valid even when the
Timer1/3/5 gate is not enabled (TMRxGE bit is
cleared).
15.5.6 TIMER1/3/5 GATE EVENT
INTERRUPT
When the Timer1/3/5 gate event interrupt is enabled, it
is possible to generate an interrupt upon the comple-
tion of a gate event. When the falling edge of TxGVAL
occurs, the TMRxGIF flag bit in the PIRx register will be
set. If the TMRxGIE bit in the PIEx register is set, then
an interrupt will be recognized.
The TMRxGIF flag bit operates even when the
Timer1/3/5 gate is not enabled (TMRxGE bit is
cleared).
TMRxGE
TxGPOL
TxG_IN
TxCKI
TxGVAL
Timer1/3/5 N N + 1 N + 2
TxGSPM
TxGGO/
TxDONE
Set by Software
Cleared by Hardware on
Falling Edge of TxGVAL
Set by Hardware on
Falling Edge of TxGVAL
Cleared by Software
Cleared by
Software
TMRxGIF
TxGTM
Counting Enabled on
Rising Edge of TxG
N + 4N + 3
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15.6 Timer1/3/5 Interrupt
The TMRx register pair (TMRxH:TMRxL) increments
from 0000h to FFFFh and overflows to 0000h. The
Timerx interrupt, if enabled, is generated on overflow
and is latched in the interrupt flag bit, TMRxIF.
Table 15-3 gives each module’s flag bit.
This interrupt can be enabled or disabled by setting or
clearing the TMRxIE bit, respectively. Table 15-4 gives
each module’s enable bit.
15.7 Resetting Timer1/3/5 Using the
ECCP Special Event Trigger
If the ECCP modules are configured to use Timerx and
to generate a Special Event Trigger in Compare mode
(CCPxM<3:0> = 1011), this signal will reset Timerx. The
trigger from ECCP2 will also start an A/D conversion if
the A/D module is enabled (For more information, see
Section 18.3.4 “Special Event Trigger”.)
The module must be configured as either a timer or
synchronous counter to take advantage of this feature.
When used this way, the CCPRxH:CCPRxL register
pair effectively becomes a Period register for Timerx.
If Timerx is running in Asynchronous Counter mode,
the Reset operation may not work.
In the event that a write to Timerx coincides with a
Special Event Trigger from an ECCP module, the write
will take precedence.
TABLE 15-3: TIMER1/3/5 INTERRUPT
FLAG BITS
Timer Module Flag Bit
1 PIR1<0>
3 PIR2<1>
5 PIR5<1>
TABLE 15-4: TIMER1/3/5 INTERRUPT
ENABLE BITS
Timer Module Flag Bit
1 PIE1<0>
3 PIE2<1>
5 PIE5<1>
Note: The Special Event Triggers from the
ECCPx module will only clear the TMR3
register’s content, but not set the TMR3IF
interrupt flag bit (PIR1<0>).
Note: The CCP and ECCP modules use Timers,
1 through 8, for some modes. The assign-
ment of a particular timer to a CCP/ECCP
module is determined by the Timer to CCP
enable bits in the CCPTMRSx registers.
For more details, see Register 18-2,
Register 18-3 and Register 19-2
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16.0 TIMER2/4/6/8 MODULES
The Timer2/4/6/8 timer modules have the following
features:
• Eight-Bit Timer register (TMRx)
• Eight-Bit Period register (PRx)
• Readable and Writable (all registers)
• Software Programmable Prescaler (1:1, 1:4, 1:16)
• Software Programmable Postscaler (1:1 to 1:16)
• Interrupt on TMRx Match of PRx
The Timer2/4/6/8 modules have a control register,
shown in Register 16-1. Timer2/4/6/8 can be shut off by
clearing control bit, TMRxON (TxCON<2>), to minimize
power consumption. The prescaler and postscaler
selection of Timer2/4/6/8 also are controlled by this
register. Figure 16-1 is a simplified block diagram of the
Timer2/4/6/8 modules.
16.1 Timer2/4/6/8 Operation
Timer2/4/6/8 can be used as the PWM time base for
the PWM mode of the ECCP modules. The TMRx reg-
isters are readable and writable, and are cleared on
any device Reset. The input clock (FOSC/4) has a
prescale option of 1:1, 1:4 or 1:16, selected by control
bits, TxCKPS<1:0> (TxCON<1:0>). The match output
of TMRx goes through a four-bit postscaler (that gives
a 1:1 to 1:16 inclusive scaling) to generate a TMRx
interrupt, latched in the flag bit, TMRxIF. Tab l e 16-1
gives each module’s flag bit.
The interrupt can be enabled or disabled by setting or
clearing the Timerx Interrupt Enable bit (TMRxIE),
shown in Tab le 16- 2 .
The prescaler and postscaler counters are cleared
when any of the following occurs:
• A write to the TMRx register
• A write to the TxCON register
• Any device Reset – Power-on Reset (POR),
MCLR Reset, Watchdog Timer Reset (WDTR) or
Brown-out Reset (BOR)
A TMRx is not cleared when a TxCON is written.
Note: Throughout this section, generic references
are used for register and bit names that are the
same, except for an ‘x’ variable that indicates
the item’s association with the Timer2, Timer4,
Timer6 or Timer8 module. For example, the
control register is named TxCON and refers to
T2CON, T4CON, T6CON and T8CON.
TABLE 16-1: TIMER2/4/6/8 FLAG BITS
Timer Module Flag Bit
2PIR1<1>
4PIR5<0>
6PIR5<2>
8PIR5<4>
TABLE 16-2: TIMER2/4/6/8 INTERRUPT
ENABLE BITS
Timer Module Flag Bit
2PIE1<1>
4PIE5<0>
6PIE5<2>
8PIE5<4>
Note: The CCP and ECCP modules use Timers,
1 through 8, for some modes. The assign-
ment of a particular timer to a CCP/ECCP
module is determined by the Timer to CCP
enable bits in the CCPTMRSx registers.
For more details, see Register 18-2,
Register 18-3 and Register 19-2.
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16.2 Timer2/4/6/8 Interrupt
The Timer2/4/6/8 modules have eight-bit Period
registers, PRx, that are both readable and writable.
Timer2/4/6/8 increment from 00h until they match PR2/
4/6/8 and then reset to 00h on the next increment cycle.
The PRx registers are initialized to FFh upon Reset.
16.3 Output of TMRx
The outputs of TMRx (before the postscaler) are used
only as a PWM time base for the ECCP modules. They
are not used as baud rate clocks for the MSSPx
modules as is the Timer2 output.
FIGURE 16-1: TIMER2/4/6/8 BLOCK DIAGRAM
REGISTER 16-1: TxCON: TIMERx CONTROL REGISTER (TIMER2/4/6/8)
U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— TxOUTPS3 TxOUTPS2 TxOUTPS1 TxOUTPS0 TMRxON TxCKPS1 TxCKPS0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-3 TxOUTPS<3:0>: Timerx Output Postscale Select bits
0000 = 1:1 Postscale
0001 = 1:2 Postscale
•
•
•
1111 = 1:16 Postscale
bit 2 TMRxON: Timerx On bit
1 = Timerx is on
0 = Timerx is off
bit 1-0 TxCKPS<1:0>: Timerx Clock Prescale Select bits
00 = Prescaler is 1
01 = Prescaler is 4
1x = Prescaler is 16
Comparator
TMRx Output
TMRx
Postscaler
Prescaler PRx
2
FOSC/4
1:1 to 1:16
1:1, 1:4, 1:16
4
TxOUTPS<3:0>
TxCKPS<1:0>
Set TMRxIF
Internal Data Bus
8
Reset
TMRx/PRx
8
8
(to PWM)
Match
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NOTES:
2012 Microchip Technology Inc. DS30575A-page 297
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17.0 REAL-TIME CLOCK AND
CALENDAR (RTCC)
The key features of the Real-Time Clock and Calendar
(RTCC) module are:
• Hardware Real-Time Clock and Calendar (RTCC)
• Provides hours, minutes and seconds using
24- hour format
• Visibility of one-half second period
• Provides calendar – weekday, date, month and
year
• Alarm configurable for half a second, one second,
10 seconds, one minute, 10 minutes, one hour,
one day, one week or one month
• Alarm repeat with decrementing counter
• Alarm with indefinite repeat – chime
• Year 2000 to 2099 leap year correction
• BCD format for smaller software overhead
• Optimized for long term battery operation
• Fractional second synchronization
• Multiple clock sources
-SOSC
-LPRC
-50 Hz
-60 Hz
• User calibration of the 32.768 kHz clock crystal
frequency with periodic auto-adjust
• Calibration to within ±2.64 seconds error per
month
• Calibrates up to 260 ppm of crystal error
The RTCC module is intended for applications where
accurate time must be maintained for an extended
period with minimum to no intervention from the CPU.
The module is optimized for low-power usage in order
to provide extended battery life, while keeping track of
time.
The module is a 100-year clock and calendar with auto-
matic leap year detection. The range of the clock is
from 00:00:00 (midnight) on January 1, 2000 to
23:59:59 on December 31, 2099.
Hours are measured in 24-hour (military time) format.
The clock provides a granularity of one second with
half-second visibility to the user.
FIGURE 17-1: RTCC BLOCK DIAGRAM
RTCC Prescalers
RTCC Timer
Comparator
Compare Registers
Repeat Counter
YEAR
MTHDY
WKDYHR
MINSEC
ALMTHDY
ALWDHR
ALMINSEC
with Masks
RTCC Interrupt Logic
RTCCON1
ALRMRPT
Alarm
Event
0.5s
RTCC Clock Domain
Alarm Pulse
RTCC Interrupt
CPU Clock Domain
RTCVALx
ALRMVALx
RTCC Pin
RTCOE
32.768 kHz Input
from SOSC Oscillator
Internal RC
(LF-INTOSC)
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17.1 RTCC MODULE REGISTERS
The RTCC module registers are divided into the
following categories:
RTCC Control Registers
• RTCCON1
• RTCCON2
• RTCCAL
• PADCFG
•ALRMCFG
•ALRMRPT
RTCC Value Registers
•RTCVALH
•RTCVALL
Both registers access the following registers:
- YEAR
-MONTH
-DAY
- WEEKDAY
-HOUR
- MINUTE
- SECOND
Alarm Value Registers
•ALRMVALH
• ALRMVALL
Both registers access the following registers:
- ALRMMNTH
-ALRMDAY
-ALRMWD
-ALRMHR
- ALRMMIN
- ALRMSEC
Note: The RTCVALH and RTCVALL registers
can be accessed through RTCRPT<1:0>
(RTCCON1<1:0>). ALRMVALH and
ALRMVALL can be accessed through
ALRMPTR<1:0> (ALRMCFG<1:0>).
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17.1.1 RTCC CONTROL REGISTERS
REGISTER 17-1: RTCCON1: RTCC CONFIGURATION REGISTER 1(1)
R/W-0 U-0 R/W-0 R-0 R-0 R/W-0 R/W-0 R/W-0
RTCEN(2)—RTCWREN
(4)RTCSYNC HALFSEC(3)RTCOE RTCPTR1 RTCPTR0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 RTCEN: RTCC Enable bit(2)
1 = RTCC module is enabled
0 = RTCC module is disabled
bit 6 Unimplemented: Read as ‘0’
bit 5 RTCWREN: RTCC Value Registers Write Enable bit(4)
1 = RTCVALH, RTCVALL and RTCCON2 registers can be written to by the user
0 = RTCVALH, RTCVALL and RTCCON2 registers are locked out from being written to by the user
bit 4 RTCSYNC: RTCC Value Registers Read Synchronization bit
1 = RTCVALH, RTCVALL and ALRMRPT registers can change while reading if a rollover ripple
results in an invalid data read. If the register is read twice and results in the same data, the data
can be assumed to be valid.
0 = RTCVALH, RTCVALL or ALRMRPT registers can be read without concern over a rollover ripple
bit 3 HALFSEC: Half-Second Status bit(3)
1 = Second half period of a second
0 = First half period of a second
bit 2 RTCOE: RTCC Output Enable bit
1 = RTCC clock output is enabled
0 = RTCC clock output is disabled
bit 1-0 RTCPTR<1:0>: RTCC Value Register Window Pointer bits
Points to the corresponding RTCC Value registers when reading the RTCVALH and RTCVALL
registers. The RTCPTR<1:0> value decrements on every read or write of RTCVALH<15:8> until it
reaches ‘00’.
RTCVALH:
00 = Minutes
01 = Weekday
10 = Month
11 = Reserved
RTCVALL:
00 = Seconds
01 = Hours
10 = Day
11 = Year
Note 1: The RTCCON1 register is only affected by a POR.
2: A write to the RTCEN bit is only allowed when RTCWREN = 1.
3: This bit is read-only; it is cleared to ‘0’ on a write to the lower half of the MINSEC register.
4: RTCWREN can only be written with the unlock sequence (see Example 17-1).
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REGISTER 17-2: RTCCAL: RTCC CALIBRATION REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CAL7 CAL6 CAL5 CAL4 CAL3 CAL2 CAL1 CAL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CAL<7:0>: RTC Drift Calibration bits
01111111 = Maximum positive adjustment; adds 508 RTC clock pulses every minute
.
.
.
00000001 = Minimum positive adjustment; adds four RTC clock pulses every minute
00000000 = No adjustment
11111111 = Minimum negative adjustment; subtracts four RTC clock pulses every minute
.
.
.
10000000 = Maximum negative adjustment; subtracts 512 RTC clock pulses every minute
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Register 17-3: RTCCON2: RTC CONFIGURATION REGISTER 2(1)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
PWCEN(1)PWCPOL(1)PWCCPRE(1)PWCSPRE(1)RTCCLKSEL1 RTCCLKSEL0 RTCSECSEL1 RTCSECSEL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 PWCEN: Power Control Enable bit(1)
1 = Power control is enabled
0 = Power control is disabled
bit 6 PWCPOL: Power Control Polarity bit(1)
1 = Power control output is active-high
0 = Power control output is active-low
bit 5 PWCCPRE: Power Control/Stability Prescaler bits(1)
1 = PWC stability window clock is divide-by-2 of source RTCC clock
0 = PWC stability window clock is divide-by-1 of source RTCC clock
bit 4 PWCSPRE: Power Control Sample Prescaler bits(1)
01 = PWC sample window clock is divide-by-2 of source RTCC clock
00 = PWC sample window clock is divide-by-1 of source RTCC clock
bit 3-2 RTCCLKSEL<1:0>: RTCC Clock Select bits
Determines the source of the internal RTCC clock, which is used for all RTCC timer operations.
11 = 60 Hz Powerline
10 = 50 Hz Powerline
01 =INTOSC
00 =SOSC
bit 1-0 RTSECSEL<1:0>: RTCC Seconds Clock Output Select bit
11 = Power control
10 = RTCC source clock is selected for the RTCC pin (pin can be LF-INTOSC or SOSC, depending on the
RTCOSC (CONFIG3L<1>) bit setting
01 = RTCC seconds clock is selected for the RTCC pin
00 = RTCC alarm pulse is selected for the RTCC pin
Note 1: The RTCCON2 register is only affected by a POR.
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REGISTER 17-4: ALRMCFG: ALARM CONFIGURATION REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ALRMEN CHIME AMASK3 AMASK2 AMASK1 AMASK0 ALRMPTR1 ALRMPTR0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ALRMEN: Alarm Enable bit
1 = Alarm is enabled (cleared automatically after an alarm event whenever ARPT<7:0> = 00h
and CHIME = 0)
0 = Alarm is disabled
bit 6 CHIME: Chime Enable bit
1 = Chime is enabled; ARPT<7:0> bits are allowed to roll over from 00h to FFh
0 = Chime is disabled; ARPT<7:0> bits stop once they reach 00h
bit 5-2 AMASK<3:0>: Alarm Mask Configuration bits
0000 = Every half second
0001 = Every second
0010 = Every 10 seconds
0011 = Every minute
0100 = Every 10 minutes
0101 = Every hour
0110 = Once a day
0111 = Once a week
1000 = Once a month
1001 = Once a year (except when configured for February 29th, once every four years)
101x = Reserved – Do not use
11xx = Reserved – Do not use
bit 1-0 ALRMPTR<1:0>: Alarm Value Register Window Pointer bits
Points to the corresponding Alarm Value registers when reading the ALRMVALH and ALRMVALL
registers. The ALRMPTR<1:0> value decrements on every read or write of ALRMVALH until it reaches
‘00’.
ALRMVALH:
00 = ALRMMIN
01 =ALRMWD
10 =ALRMMNTH
11 = Unimplemented
ALRMVALL:
00 = ALRMSEC
01 =ALRMHR
10 =ALRMDAY
11 = Unimplemented
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17.1.2 RTCVALH AND RTCVALL
REGISTER MAPPINGS
The registers described in this section are the targets
or sources for writes or reads to the RTCVALH and
RTCVALL in the order they will appear when accessed
through the RTCCON1<RTCPTR> pointer. For more
information on RTCVAL register mapping, please see
Section 17.2.8 “Register Mapping”.
REGISTER 17-5: ALRMRPT: ALARM REPEAT REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ARPT7 ARPT6 ARPT5 ARPT4 ARPT3 ARPT2 ARPT1 ARPT0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 ARPT<7:0>: Alarm Repeat Counter Value bits
11111111 = Alarm will repeat 255 more times
.
.
.
00000000 = Alarm will not repeat
The counter decrements on any alarm event. The counter is prevented from rolling over from 00h to
FFh unless CHIME = 1.
REGISTER 17-6: RESERVED REGISTER (RTCVALH when RTCPTR<1:0> = 11)
U-0 U-0 U-0 U-0 U-0 U-0 U-0 U-0
— — — — — — — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 Unimplemented: Read as ‘0’
Note: A read or write to the RTCVALH register
when RTCPTR<1:0> = 11 is necessary to
automatically decrement RTCPTR.
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REGISTER 17-7: YEAR: YEAR VALUE REGISTER(1) (RTCVALL when RTCPTR<1:0> = 11)
R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
YRTEN3 YRTEN2 YRTEN1 YRTEN0 YRONE3 YRONE2 YRONE1 YRONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 YRTEN<3:0>: Binary Coded Decimal Value of Year’s Tens Digit bits
Contains a value from 0 to 9.
bit 3-0 YRONE<3:0>: Binary Coded Decimal Value of Year’s Ones Digit bits
Contains a value from 0 to 9.
Note 1: A write to the YEAR register is only allowed when RTCWREN = 1.
REGISTER 17-8: MONTH: MONTH VALUE REGISTER(1) (RTCVALH when RTCPTR<1:0> = 10)
U-0 U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-x
— — — MTHTEN0 MTHONE3 MTHONE2 MTHONE1 MTHONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘0’
bit 4 MTHTEN0: Binary Coded Decimal Value of Month’s Tens Digit bit
Contains a value of 0 or 1.
bit 3-0 MTHONE<3:0>: Binary Coded Decimal Value of Month’s Ones Digit bits
Contains a value from 0 to 9.
Note 1: A write to this register is only allowed when RTCWREN = 1.
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REGISTER 17-9: DAY: DAY VALUE REGISTER(1) (RTCVALL when RTCPTR<1:0> = 10)
U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
—— DAYTEN1 DAYTEN0 DAYONE3 DAYONE2 DAYONE1 DAYONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 Unimplemented: Read as ‘0’
bit 5-4 DAYTEN<1:0>: Binary Coded Decimal value of Day’s Tens Digit bits
Contains a value from 0 to 3.
bit 3-0 DAYONE<3:0>: Binary Coded Decimal Value of Day’s Ones Digit bits
Contains a value from 0 to 9.
Note 1: A write to this register is only allowed when RTCWREN = 1.
REGISTER 17-10: WEEKDAY: WEEKDAY VALUE REGISTER(1)
(RTCVALH when RTCPTR<1:0> = 01)
U-0 U-0 U-0 U-0 U-0 R/W-x R/W-x R/W-x
— — — — — WDAY2 WDAY1 WDAY0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-3 Unimplemented: Read as ‘0’
bit 2-0 WDAY<2:0>: Binary Coded Decimal Value of Weekday Digit bits
Contains a value from 0 to 6.
Note 1: A write to this register is only allowed when RTCWREN = 1.
REGISTER 17-11: HOUR: HOUR VALUE REGISTER(1) (RTCVALL when RTCPTR<1:0> = 01)
U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
—— HRTEN1 HRTEN0 HRONE3 HRONE2 HRONE1 HRONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 Unimplemented: Read as ‘0’
bit 5-4 HRTEN<1:0>: Binary Coded Decimal Value of Hour’s Tens Digit bits
Contains a value from 0 to 2.
bit 3-0 HRONE<3:0>: Binary Coded Decimal Value of Hour’s Ones Digit bits
Contains a value from 0 to 9.
Note 1: A write to this register is only allowed when RTCWREN = 1.
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REGISTER 17-12: MINUTE: MINUTE VALUE REGISTER (RTCVALH when RTCPTR<1:0> = 00)
U-0 R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
— MINTEN2 MINTEN1 MINTEN0 MINONE3 MINONE2 MINONE1 MINONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-4 MINTEN<2:0>: Binary Coded Decimal Value of Minute’s Tens Digit bits
Contains a value from 0 to 5.
bit 3-0 MINONE<3:0>: Binary Coded Decimal Value of Minute’s Ones Digit bits
Contains a value from 0 to 9.
REGISTER 17-13: SECOND: SECOND VALUE REGISTER (RTCVALL when RTCPTR<1:0> = 00)
U-0 R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
— SECTEN2 SECTEN1 SECTEN0 SECONE3 SECONE2 SECONE1 SECONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-4 SECTEN<2:0>: Binary Coded Decimal Value of Second’s Tens Digit bits
Contains a value from 0 to 5.
bit 3-0 SECONE<3:0>: Binary Coded Decimal Value of Second’s Ones Digit bits
Contains a value from 0 to 9.
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17.1.3 ALRMVALH AND ALRMVALL
REGISTER MAPPINGS
The registers described in this section are the targets
or sources for writes or reads to the ALRMVALH and
ALRMVALL in the order they will appear when
accessed through the ALRMCFG<ALRMPTR> pointer.
For more information on ALRMVAL register mapping,
please see Section 17.2.8 “Register Mapping”.
REGISTER 17-14: ALRMMNTH: ALARM MONTH VALUE REGISTER(1)
(ALRMVALH when ALRMPTR<1:0> = 10)
U-0 U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-x
— — — MTHTEN0 MTHONE3 MTHONE2 MTHONE1 MTHONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘0’
bit 4 MTHTEN0: Binary Coded Decimal Value of Month’s Tens Digit bits
Contains a value of 0 or 1.
bit 3-0 MTHONE<3:0>: Binary Coded Decimal Value of Month’s Ones Digit bits
Contains a value from 0 to 9.
Note 1: A write to this register is only allowed when RTCWREN = 1.
REGISTER 17-15: ALRMDAY: ALARM DAY VALUE REGISTER(1)
(ALRMVALL when ALRMPTR<1:0> = 10)
U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
—— DAYTEN1 DAYTEN0 DAYONE3 DAYONE2 DAYONE1 DAYONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 Unimplemented: Read as ‘0’
bit 5-4 DAYTEN<1:0>: Binary Coded Decimal Value of Day’s Tens Digit bits
Contains a value from 0 to 3.
bit 3-0 DAYONE<3:0>: Binary Coded Decimal Value of Day’s Ones Digit bits
Contains a value from 0 to 9.
Note 1: A write to this register is only allowed when RTCWREN = 1.
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REGISTER 17-16: ALRMWD: ALARM WEEKDAY VALUE REGISTER(1)
(ALRMVALH WHEN ALRMPTR<1:0> = 01)
U-0 U-0 U-0 U-0 U-0 R/W-x R/W-x R/W-x
— — — — — WDAY2 WDAY1 WDAY0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-3 Unimplemented: Read as ‘0’
bit 2-0 WDAY<2:0>: Binary Coded Decimal Value of Weekday Digit bits
Contains a value from 0 to 6.
Note 1: A write to this register is only allowed when RTCWREN = 1.
REGISTER 17-17: ALRMHR: ALARM HOURS VALUE REGISTER(1)
(ALRMVALL when ALRMPTR<1:0> = 01)
U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
—— HRTEN1 HRTEN0 HRONE3 HRONE2 HRONE1 HRONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 Unimplemented: Read as ‘0’
bit 5-4 HRTEN<1:0>: Binary Coded Decimal Value of Hour’s Tens Digit bits
Contains a value from 0 to 2.
bit 3-0 HRONE<3:0>: Binary Coded Decimal Value of Hour’s Ones Digit bits
Contains a value from 0 to 9.
Note 1: A write to this register is only allowed when RTCWREN = 1.
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REGISTER 17-18: ALRMMIN: ALARM MINUTES VALUE REGISTER
(ALRMVALH when ALRMPTR<1:0> = 00)
U-0 R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
— MINTEN2 MINTEN1 MINTEN0 MINONE3 MINONE2 MINONE1 MINONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-4 MINTEN<2:0>: Binary Coded Decimal Value of Minute’s Tens Digit bits
Contains a value from 0 to 5.
bit 3-0 MINONE<3:0>: Binary Coded Decimal Value of Minute’s Ones Digit bits
Contains a value from 0 to 9.
REGISTER 17-19: ALRMSEC: ALARM SECONDS VALUE REGISTER
(ALRMVALL when ALRMPTR<1:0> = 00)
U-0 R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
— SECTEN2 SECTEN1 SECTEN0 SECONE3 SECONE2 SECONE1 SECONE0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-4 SECTEN<2:0>: Binary Coded Decimal Value of Second’s Tens Digit bits
Contains a value from 0 to 5.
bit 3-0 SECONE<3:0>: Binary Coded Decimal Value of Second’s Ones Digit bits
Contains a value from 0 to 9.
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17.1.4 RTCEN BIT WRITE
RTCWREN (RTCCON1<5>) must be set before a write
to RTCEN can take place. Any write to the RTCEN bit,
while RTCWREN = 0, will be ignored.
Like the RTCEN bit, the RTCVALH and RTCVALL
registers can only be written to when RTCWREN = 1.
A write to these registers, while RTCWREN = 0, will be
ignored.
17.2 Operation
17.2.1 REGISTER INTERFACE
The register interface for the RTCC and alarm values is
implemented using the Binary Coded Decimal (BCD)
format. This simplifies the firmware when using the
module, as each of the digits is contained within its own
4-bit value (see Figure 17-2 and Figure 17-3).
FIGURE 17-2: TIMER DIGIT FORMAT
FIGURE 17-3: ALARM DIGIT FORMAT
0-60-9 0-9 0-3 0-9
0-9 0-9 0-90-2 0-5 0-5 0/1
Day of WeekYear Day
Hours
(24-hour format) Minutes Seconds
1/2 Second Bit
0-1 0-9
Month
(binary format)
0-60-3 0-9
0-9 0-9 0-90-2 0-5 0-5
Day of WeekDay
Hours
(24-hour format) Minutes Seconds
0-1 0-9
Month
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17.2.2 CLOCK SOURCE
As mentioned earlier, the RTCC module is intended to
be clocked by an external Real-Time Clock (RTC) crys-
tal, oscillating at 32.768 kHz, but an internal oscillator
can be used. The RTCC clock selection is decided by
the RTCOSC bit (CONFIG3L<0>).
Calibration of the crystal can be done through this
module to yield an error of 3 seconds or less per month.
(For further details, see Section 17.2.9 “Calibration”.)
FIGURE 17-4: CLOCK SOURCE MULTIPLEXING
17.2.2.1 Real-Time Clock Enable
The RTCC module can be clocked by an external,
32.768 kHz crystal (SOSC Oscillator) or the LF-INTOSC
Oscillator, which can be selected in CONFIG3L<0>.
If the external clock is used, the SOSC Oscillator
should be enabled. If LF-INTOSC is providing the clock,
the INTOSC clock can be brought out to the RTCC pin
by the RTSECSEL<1:0> bits (RTCCON2<1:0>).
17.2.3 DIGIT CARRY RULES
This section explains which timer values are affected
when there is a rollover:
• Time of Day: From 23:59:59 to 00:00:00 with a
carry to the Day field
• Month: From 12/31 to 01/01 with a carry to the
Year field
• Day of Week: From 6 to 0 with no carry (see
Table 17-1)
• Year Carry: From 99 to 00; this also surpasses the
use of the RTCC
For the day-to-month rollover schedule, see Table 17-2.
Because the following values are in BCD format, the
carry to the upper BCD digit occurs at the count of 10,
not 16 (SECONDS, MINUTES, HOURS, WEEKDAY,
DAYS and MONTHS).
TABLE 17-1: DAY OF WEEK SCHEDULE
TABLE 17-2: DAY TO MONTH ROLLOVER
SCHEDULE
Note 1: Writing to the lower half of the MINSEC register resets all counters, allowing fraction of a second synchronization;
clock prescaler is held in Reset when RTCEN = 0.
32.768 kHz XTAL
1:16384 Half Second(1)
Half-Second
Clock One Second Clock
Year
Month
Day
Day of Week
Second Hour:Minute
Clock Prescaler(1)
from SOSC
Internal RC
RTCCON1
Day of Week
Sunday 0
Monday 1
Tuesday 2
Wednesday 3
Thursday 4
Friday 5
Saturday 6
Month Maximum Day Field
01 (January) 31
02 (February) 28 or 29(1)
03 (March) 31
04 (April) 30
05 (May) 31
06 (June) 30
07 (July) 31
08 (August) 31
09 (September) 30
10 (October) 31
11 (November) 30
12 (December) 31
Note 1: See Section 17.2.4 “Leap Year”.
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17.2.4 LEAP YEAR
Since the year range on the RTCC module is 2000 to
2099, the leap year calculation is determined by any year
divisible by four in the above range. Only February is
affected in a leap year.
February will have 29 days in a leap year and 28 days in
any other year.
17.2.5 GENERAL FUNCTIONALITY
All Timer registers containing a time value of seconds or
greater are writable. The user configures the time by
writing the required year, month, day, hour, minutes and
seconds to the Timer registers, via register pointers.
(See Section 17.2.8 “Register Mapping”.)
The timer uses the newly written values and proceeds
with the count from the required starting point.
The RTCC is enabled by setting the RTCEN bit
(RTCCON1<7>). If enabled, while adjusting these
registers, the timer still continues to increment. However,
any time the MINSEC register is written to, both of the
timer prescalers are reset to ‘0’. This allows fraction of a
second synchronization.
The Timer registers are updated in the same cycle as
the write instruction’s execution by the CPU. The user
must ensure that when RTCEN = 1, the updated
registers will not be incremented at the same time. This
can be accomplished in several ways:
• By checking the RTCSYNC bit (RTCCON1<4>)
• By checking the preceding digits from which a
carry can occur
• By updating the registers immediately following
the seconds pulse (or an alarm interrupt)
The user has visibility to the half-second field of the
counter. This value is read-only and can be reset only
by writing to the lower half of the SECONDS register.
17.2.6 SAFETY WINDOW FOR REGISTER
READS AND WRITES
The RTCSYNC bit indicates a time window during
which the RTCC clock domain registers can be safely
read and written without concern about a rollover.
When RTCSYNC = 0, the registers can be safely
accessed by the CPU.
Whether RTCSYNC = 1 or 0, the user should employ a
firmware solution to ensure that the data read did not
fall on a rollover boundary, resulting in an invalid or
partial read. This firmware solution would consist of
reading each register twice and then comparing the two
values. If the two values matched, then a rollover did
not occur.
17.2.7 WRITE LOCK
In order to perform a write to any of the RTCC Timer
registers, the RTCWREN bit (RTCCON1<5>) must be
set.
To avoid accidental writes to the RTCC Timer register,
it is recommended that the RTCWREN bit
(RTCCON1<5>) be kept clear when not writing to the
register. For the RTCWREN bit to be set, there is only
one instruction cycle time window allowed between the
55h/AA sequence and the setting of RTCWREN. For
that reason, it is recommended that users follow the
code example in Example 17-1.
EXAMPLE 17-1: SETTING THE RTCWREN
BIT
17.2.8 REGISTER MAPPING
To limit the register interface, the RTCC Timer and
Alarm Timer registers are accessed through
corresponding register pointers. The RTCC Value
register window (RTCVALH and RTCVALL) uses the
RTCPTRx bits (RTCCON1<1:0>) to select the required
Timer register pair.
By reading or writing to the RTCVALH register, the
RTCC Pointer value (RTCPTR<1:0>) decrements by ‘1’
until it reaches ‘00’. When ‘00’ is reached, the
MINUTES and SECONDS value is accessible through
RTCVALH and RTCVALL until the pointer value is
manually changed.
TABLE 17-3: RTCVALH AND RTCVALL
REGISTER MAPPING
The Alarm Value register windows (ALRMVALH and
ALRMVALL) use the ALRMPTR bits (ALRMCFG<1:0>)
to select the desired Alarm register pair.
By reading or writing to the ALRMVALH register, the
Alarm Pointer value, ALRMPTR<1:0>, decrements by ‘1’
until it reaches ‘00’. When it reaches ‘00’, the ALRMMIN
and ALRMSEC values are accessible through
ALRMVALH and ALRMVALL until the pointer value is
manually changed.
movlw 0x55
movwf EECON2
movlw 0xAA
movwf EECON2
bsf RTCCON1,RTCWREN
RTCPTR<1:0>
RTCC Value Register Window
RTCVALH RTCVALL
00 MINUTES SECONDS
01 WEEKDAY HOURS
10 MONTH DAY
11 — YEAR
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TABLE 17-4: ALRMVAL REGISTER
MAPPING
17.2.9 CALIBRATION
The real-time crystal input can be calibrated using the
periodic auto-adjust feature. When properly calibrated,
the RTCC can provide an error of less than three
seconds per month.
To perform this calibration, find the number of error
clock pulses and store the value into the lower half of
the RTCCAL register. The 8-bit signed value, loaded
into RTCCAL, is multiplied by four and will either be
added or subtracted from the RTCC timer, once every
minute.
To calibrate the RTCC module:
1. Use another timer resource on the device to find
the error of the 32.768 kHz crystal.
2. Convert the number of error clock pulses per
minute (see Equation 17-1).
• If the oscillator is faster than ideal (negative
result from Step 2), the RCFGCALL register
value needs to be negative. This causes the
specified number of clock pulses to be
subtracted from the timer counter once every
minute.
• If the oscillator is slower than ideal (positive
result from Step 2), the RCFGCALL register
value needs to be positive. This causes the
specified number of clock pulses to be added to
the timer counter once every minute.
3. Load the RTCCAL register with the correct
value.
Writes to the RTCCAL register should occur only when
the timer is turned off or immediately after the rising
edge of the seconds pulse.
17.3 Alarm
The Alarm features and characteristics are:
• Configurable from half a second to one year
• Enabled using the ALRMEN bit (ALRMCFG<7>,
Register 17-4)
• Offers one-time and repeat alarm options
17.3.1 CONFIGURING THE ALARM
The alarm feature is enabled using the ALRMEN bit.
This bit is cleared when an alarm is issued. The bit will
not be cleared if the CHIME bit = 1 or if ALRMRPT 0.
The interval selection of the alarm is configured
through the ALRMCFG bits (AMASK<3:0>); see
Figure 17-5. These bits determine which and how
many digits of the alarm must match the clock value for
the alarm to occur.
The alarm can also be configured to repeat based on a
preconfigured interval. The number of times this
occurs, after the alarm is enabled, is stored in the
ALRMRPT register.
ALRMPTR<1:0>
Alarm Value Register Window
ALRMVALH ALRMVALL
00 ALRMMIN ALRMSEC
01 ALRMWD ALRMHR
10 ALRMMNTH ALRMDAY
11 ——
EQUATION 17-1: CONVERTING ERROR
CLOCK PULSES
(Ideal Frequency (32,758) – Measured Frequency) * 60 =
Error Clocks per Minute
Note: In determining the crystal’s error value, it
is the user’s responsibility to include the
crystal’s initial error from drift due to
temperature or crystal aging.
Note: While the alarm is enabled (ALRMEN = 1),
changing any of the registers, other than
the RTCCAL, ALRMCFG and ALRMRPT
registers and the CHIME bit, can result in a
false alarm event leading to a false alarm
interrupt. To avoid this, only change the
timer and alarm values while the alarm is
disabled (ALRMEN = 0). It is recommended
that the ALRMCFG and ALRMRPT
registers and CHIME bit be changed when
RTCSYNC = 0.
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FIGURE 17-5: ALARM MASK SETTINGS
When ALRMCFG = 00 and the CHIME bit = 0
(ALRMCFG<6>), the repeat function is disabled and
only a single alarm will occur. The alarm can be
repeated up to 255 times by loading the ALRMRPT
register with FFh.
After each alarm is issued, the ALRMRPT register is
decremented by one. Once the register has reached
‘00’, the alarm will be issued one last time.
After the alarm is issued a last time, the ALRMEN bit is
cleared automatically and the alarm turned off. Indefinite
repetition of the alarm can occur if the CHIME bit = 1.
When CHIME = 1, the alarm is not disabled when the
ALRMRPT register reaches ‘00’, but it rolls over to FF
and continues counting indefinitely.
17.3.2 ALARM INTERRUPT
At every alarm event, an interrupt is generated. Addi-
tionally, an alarm pulse output is provided that operates
at half the frequency of the alarm.
The alarm pulse output is completely synchronous with
the RTCC clock and can be used as a trigger clock to
other peripherals. This output is available on the RTCC
pin. The output pulse is a clock with a 50% duty cycle
and a frequency half that of the alarm event (see
Figure 17-6).
The RTCC pin can also output the seconds clock. The
user can select between the alarm pulse, generated by
the RTCC module, or the seconds clock output.
The RTSECSEL<1:0> bits (RTCCON2<1:0>) select
between these two outputs:
• Alarm pulse – RTSECSEL<1:0> = 00
• Seconds clock – RTSECSEL<1:0> = 01
Note 1: Annually, except when configured for February 29.
s
ss
mss
mm s s
hh mm ss
dhhmmss
dd hh mm ss
mm d d h h mm s s
Day of the
Week Month Day Hours Minutes Seconds
Alarm Mask Setting
AMASK<3:0>
0000 – Every half second
0001 – Every second
0010 – Every 10 seconds
0011 – Every minute
0100 – Every 10 minutes
0101 – Every hour
0110 – Every day
0111 – Every week
1000 – Every month
1001 – Every year(1)
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FIGURE 17-6: TIMER PULSE GENERATION
17.4 Sleep Mode
The timer and alarm continue to operate while in Sleep
mode. The operation of the alarm is not affected by
Sleep, as an alarm event can always wake-up the
CPU.
The Idle mode does not affect the operation of the timer
or alarm.
17.5 Reset
17.5.1 DEVICE RESET
When a device Reset occurs, the ALRMRPT register is
forced to its Reset state, causing the alarm to be
disabled (if enabled prior to the Reset). If the RTCC
was enabled, it will continue to operate when a basic
device Reset occurs.
17.5.2 POWER-ON RESET (POR)
The RTCCON1 and ALRMRPT registers are reset only
on a POR. Once the device exits the POR state, the
clock registers should be reloaded with the desired
values.
The timer prescaler values can be reset only by writing
to the SECONDS register. No device Reset can affect
the prescalers.
RTCEN bit
ALRMEN bit
RTCC Alarm Event
RTCC Pin
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17.6 Register Maps
Table 17-5, Tab le 17- 6 and Table 17-7 summarize the
registers associated with the RTCC module.
TABLE 17-5: RTCC CONTROL REGISTERS
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
RTCCON1 RTCEN — RTCWREN RTCSYNC HALFSEC RTCOE RTCPTR1 RTCPTR0
RTCCAL CAL7 CAL6 CAL5 CAL4 CAL3 CAL2 CAL1 CAL0
RTCCON2 PWCEN PWCPOL PWCCPRE PWCSPRE RTCCLKSEL1 RTCCLKSEL0 RTCSECSEL1 RTCSECSEL
ALRMCFG ALRMEN CHIME AMASK3 AMASK2 AMASK1 AMASK0 ALRMPTR1 ALRMPTR0
ALRMRPT ARPT7 ARPT6 ARPT5 ARPT4 ARPT3 ARPT2 ARPT1 ARPT0
PMD3 TXMMD CTMUMD ADCMD RTCCMD LCDMD PSPMD REFO1MD REFO2MD
Legend:
— = unimplemented, read as ‘
0
’. Reset values are shown in hexadecimal for 80-pin devices.
TABLE 17-6: RTCC VALUE REGISTERS
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
RTCVALH RTCC Value High Register Window based on RTCPTR<1:0>
RTCVALL RTCC Value Low Register Window based on RTCPTR<1:0>
TABLE 17-7: ALARM VALUE REGISTERS
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
ALRMVALH Alarm Value High Register Window based on ALRMPTR<1:0>
ALRMVALL Alarm Value Low Register Window based on ALRMPTR<1:0>
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18.0 ENHANCED
CAPTURE/COMPARE/PWM
(ECCP) MODULE
PIC18F97J94 family devices have three Enhanced
Capture/Compare/PWM (ECCP) modules: ECCP1,
ECCP2 and ECCP3. These modules contain a 16-bit
register, which can operate as a 16-bit Capture register,
a 16-bit Compare register or a PWM Master/Slave Duty
Cycle register. These ECCP modules are upward
compatible with CCP
ECCP1, ECCP2 and ECCP3 are implemented as stan-
dard CCP modules with enhanced PWM capabilities.
These include:
• Provision for two or four output channels
• Output Steering modes
• Programmable polarity
• Programmable dead-band control
• Automatic shutdown and restart
The enhanced features are discussed in detail in
Section 18.4 “PWM (Enhanced Mode)”.
The ECCP1, ECCP2 and ECCP3 modules use the
ECCP Control registers, CCP1CON, CCP2CON and
CCP3CON. The control registers, CCP4CON through
CCP10CON, are for the modules, CCP4 through
CCP10.
Note: Throughout this section, generic references
are used for register and bit names that are
the same, except for an ‘x’ variable that indi-
cates the item’s association with the CCP1,
CCP2 or CCP3 module. For example, the
control register is named CCPxCON and
refers to CCP1CON, CCP2CON and
CCP3CON.
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REGISTER 18-1: CCPxCON: ENHANCED CAPTURE/COMPARE/PWM x CONTROL
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
PxM1 PxM0
DCxB1 DCxB0
CCPxM3 CCPxM2 CCPxM1 CCPxM0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 PxM<1:0>: Enhanced PWM Output Configuration bits
If CCPxM<3:2> = 00, 01, 10:
xx = PxA is assigned as the capture/compare input/output; PxB, PxC and PxD are assigned as port pins
If CCPxM<3:2> = 11:
00 = Single output: PxA, PxB, PxC and PxD are controlled by steering (see Section 18.4.7 “Pulse
Steering Mode”)
01 = Full-bridge output forward: PxD is modulated; PxA is active; PxB, PxC are inactive
10 = Half-bridge output: PxA, PxB are modulated with dead-band control; PxC and PxD are
assigned as port pins
11 = Full-bridge output reverse: PxB is modulated; PxC is active; PxA and PxD are inactive
bit 5-4 DCxB<1:0>: PWM Duty Cycle bit
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs of the 10-bit PWM duty cycle. The eight MSbs of the duty cycle are found
in CCPRxL.
bit 3-0 CCPxM<3:0>: CCPx Mode Select bits
0000 = Capture/Compare/PWM off (resets ECCPx module)
0001 = Reserved
0010 = Compare mode: Toggle output on match
0011 = Reserved
0100 = Capture mode: Every falling edge
0101 = Capture mode: Every rising edge
0110 = Capture mode: Every fourth rising edge
0111 = Capture mode: Every 16th rising edge
1000 = Compare mode: Initialize ECCPx pin low, set output on compare match (set CCPxIF)
1001 = Compare mode: Initialize ECCPx pin high, clear output on compare match (set CCPxIF)
1010 = Compare mode: Generate software interrupt only, ECCPx pin reverts to I/O state
1011 = Compare mode: Trigger special event (ECCPx resets TMR1 or TMR3, starts A/D conversion,
sets CCPxIF bit)
1100 = PWM mode: PxA and PxC are active-high; PxB and PxD are active-high
1101 = PWM mode: PxA and PxC are active-high; PxB and PxD are active-low
1110 = PWM mode: PxA and PxC are active-low; PxB and PxD are active-high
1111 = PWM mode: PxA and PxC are active-low; PxB and PxD are active-low
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REGISTER 18-2: CCPTMRS0: CCP TIMER SELECT 0 REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
C3TSEL1 C3TSEL0 C2TSEL2 C2TSEL1 C2TSEL0 C1TSEL2 C1TSEL1 C1TSEL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 C3TSEL<1:0>: CCP3 Timer Selection bits
00 = CCP3 is based off of TMR1/TMR2
01 = CCP3 is based off of TMR3/TMR4
10 = CCP3 is based off of TMR3/TMR6
11 = CCP3 is based off of TMR3/TMR8
bit 5-3 C2TSEL<2:0>: CCP2 Timer Selection bits
000 = CCP2 is based off of TMR1/TMR2
001 = CCP2 is based off of TMR3/TMR4
010 = CCP2 is based off of TMR3/TMR6
011 = CCP2 is based off of TMR3/TMR8
100 = Reserved; do not use
101 = Reserved; do not use
110 = Reserved; do not use
111 = Reserved; do not use
bit 2-0 C1TSEL<2:0>: CCP1 Timer Selection bits
000 = CCP1 is based off of TMR1/TMR2
001 = CCP1 is based off of TMR3/TMR4
010 = CCP1 is based off of TMR3/TMR6
011 = CCP1 is based off of TMR3/TMR8
100 = Reserved; do not use
101 = Reserved; do not use
110 = Reserved; do not use
111 = Reserved; do not use
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In addition to the expanded range of modes available
through the CCPxCON, the ECCP modules have three
additional registers associated with Enhanced PWM
operation, Pulse Steering Control and auto-shutdown
features. They are:
• ECCPxDEL – Enhanced PWM x Control
• PSTRxCON – Pulse Steering x Control
• ECCPxAS – Auto-Shutdown x Control
18.1 ECCP Outputs and Configuration
The Enhanced CCP module may have up to four PWM
outputs, depending on the selected operating mode.
These outputs, designated as PxA through PxD, are
routed through the PPS-Lite module. Therefore, individ-
ual functions can be mapped to any of the remappable
I/O pins (RPn). The outputs that are active depend on
the ECCP operating mode selected. The pin
assignments are summarized in Table 18-3.
To configure the I/O pins as PWM outputs, the proper
PWM mode must be selected by setting the PxM<1:0>
and CCPxM<3:0> bits. The appropriate TRIS direction
bits for the port pins must also be set as outputs
Table 18-3.
18.1.1 ECCP MODULE AND TIMER
RESOURCES
The ECCP modules use Timers, 1, 2, 3, 4, 6 or 8,
depending on the mode selected. These timers are
available to CCP modules in Capture, Compare or PWM
modes, as shown in Table 18-1.
TABLE 18-1: ECCP MODE – TIMER
RESOURCE
The assignment of a particular timer to a module is
determined by the timer to ECCP enable bits in the
CCPTMRS0 register (Register 18-2). The interactions
between the two modules are depicted in Figure 18-1.
Capture operations are designed to be used when the
timer is configured for Synchronous Counter mode.
Capture operations may not work as expected if the
associated timer is configured for Asynchronous Counter
mode.
ECCP Mode Timer Resource
Capture Timer1 or Timer3
Compare Timer1 or Timer3
PWM Timer2, Timer4, Timer6 or Timer8
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18.2 Capture Mode
In Capture mode, the CCPRxH:CCPRxL register pair
captures the 16-bit value of the TMR1 or TMR3
registers when an event occurs on the corresponding
ECCPx pin. An event is defined as one of the following:
• Every falling edge
• Every rising edge
• Every fourth rising edge
•Every 16
th rising edge
The event is selected by the mode select bits,
CCPxM<3:0> (CCPxCON<3:0>). When a capture is
made, the interrupt request flag bit, CCPxIF, is set (see
Table 18-2). The flag must be cleared by software. If
another capture occurs before the value in the
CCPRxH/L register is read, the old captured value is
overwritten by the new captured value.
18.2.1 ECCP PIN CONFIGURATION
In Capture mode, the appropriate ECCPx pin should be
configured as an input by setting the corresponding
TRIS direction bit.
18.2.2 TIMER1/2/3/4/5/6/8 MODE
SELECTION
The timers that are to be used with the capture feature
(Timer1/2/3/4/5/6 or 8) must be running in Timer mode
or Synchronized Counter mode. In Asynchronous
Counter mode, the capture operation will not work. The
timer to be used with each ECCP module is selected in
the CCPTMRS0 register (Register 18-2).
18.2.3 SOFTWARE INTERRUPT
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep the
CCPxIE interrupt enable bit clear to avoid false interrupts.
The interrupt flag bit, CCPxIF, should also be cleared
following any such change in operating mode.
18.2.4 ECCP PRESCALER
There are four prescaler settings in Capture mode; they
are specified as part of the operating mode selected by
the mode select bits (CCPxM<3:0>). Whenever the
ECCP module is turned off, or Capture mode is dis-
abled, the prescaler counter is cleared. This means
that any Reset will clear the prescaler counter.
Switching from one capture prescaler to another may
generate an interrupt. Also, the prescaler counter will
not be cleared; therefore, the first capture may be from
a non-zero prescaler. Example 18-1 provides the
recommended method for switching between capture
prescalers. This example also clears the prescaler
counter and will not generate the “false” interrupt.
EXAMPLE 18-1: CHANGING BETWEEN
CAPTURE PRESCALERS
FIGURE 18-1: CAPTURE MODE OPERATION BLOCK DIAGRAM
TABLE 18-2: ECCP1/2/3 INTERRUPT FLAG
BITS
ECCP Module Flag Bit
1 PIR3<1>
2 PIR3<2>
3 PIR4<0>
Note: If the ECCPx pin is configured as an out-
put, a write to the port can cause a capture
condition.
CLRF CCP1CON ; Turn ECCP module off
MOVLW NEW_CAPT_PS ; Load WREG with the
; new prescaler mode
; value and ECCP ON
MOVWF CCP1CON ; Load CCP1CON with
; this value
CCPR1H CCPR1L
TMR1H TMR1L
Set CCP1IF
TMR3
Enable
Q1:Q4
CCP1CON<3:0>
ECCP1 Pin
TMR1
Enable
C1TSEL0
4
4
C1TSEL1
C1TSEL2
C1TSEL0
C1TSEL1
C1TSEL2
and
Edge Detect
Prescaler
1, 4, 16
TMR3H TMR3L
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18.3 Compare Mode
In Compare mode, the 16-bit CCPRx register value is
constantly compared against the Timer register pair
value selected in the CCPTMR0 register. When a
match occurs, the ECCPx pin can be:
• Driven high
•Driven low
• Toggled (high-to-low or low-to-high)
• Unchanged (that is, reflecting the state of the I/O
latch)
The action on the pin is based on the value of the mode
select bits (CCPxM<3:0>). At the same time, the
interrupt flag bit, CCPxIF, is set.
18.3.1 ECCPx PIN CONFIGURATION
Users must configure the ECCPx pin as an output by
clearing the appropriate TRIS bit.
18.3.2 TIMER1/2/3/4/5/6/8 MODE
SELECTION
Timer1/2/3/4, 6 or 8, must be running in Timer mode or
Synchronized Counter mode if the ECCP module is
using the compare feature. In Asynchronous Counter
mode, the compare operation will not work reliably.
18.3.3 SOFTWARE INTERRUPT MODE
When the Generate Software Interrupt mode is chosen
(CCPxM<3:0> = 1010), the ECCPx pin is not affected;
only the CCPxIF interrupt flag is affected.
18.3.4 SPECIAL EVENT TRIGGER
The ECCP module is equipped with a Special Event
Trigger. This is an internal hardware signal generated
in Compare mode to trigger actions by other modules.
The Special Event Trigger is enabled by selecting
the Compare Special Event Trigger mode
(CCPxM<3:0> = 1011).
The Special Event Trigger resets the Timer register pair
for whichever timer resource is currently assigned as the
module’s time base. This allows the CCPRx registers to
serve as a programmable period register for either timer.
The Special Event Trigger can also start an A/D conver-
sion. In order to do this, the A/D Converter must
already be enabled.
FIGURE 18-2: COMPARE MODE OPERATION BLOCK DIAGRAM
Note: Clearing the CCPxCON register will force
the ECCPx compare output latch (depend-
ing on device configuration) to the default
low level. This is not the PORTx I/O data
latch.
TMR1H TMR1L
TMR3H TMR3L
CCPR1H CCPR1L
Set CCP1IF
1
0
Q
S
R
Output
Logic
ECCP1 Pin
TRIS
CCP1CON<3:0>
Output Enable
4
(Timer1/Timer3 Reset, A/D Trigger)
Compare
Match
C1TSEL0
C1TSEL1
C1TSEL2
Special Event Trigger
Comparator
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18.4 PWM (Enhanced Mode)
The Enhanced PWM mode can generate a PWM signal
on up to four different output pins, with up to 10 bits of
resolution. It can do this through four different PWM
Output modes:
• Single PWM
• Half-Bridge PWM
• Full-Bridge PWM, Forward mode
• Full-Bridge PWM, Reverse mode
To select an Enhanced PWM mode, the PxM bits of the
CCPxCON register must be set appropriately.
The PWM outputs are multiplexed with I/O pins and are
designated: PxA, PxB, PxC and PxD. The polarity of the
PWM pins is configurable and is selected by setting the
CCPxM bits in the CCPxCON register appropriately.
Table 18-1 provides the pin assignments for each
Enhanced PWM mode.
Figure 18-3 provides an example of a simplified block
diagram of the Enhanced PWM module.
FIGURE 18-3: EXAMPLE SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODE
Note: To prevent the generation of an
incomplete waveform when the PWM is
first enabled, the ECCP module waits until
the start of a new PWM period before
generating a PWM signal.
CCPRxL
CCPRxH (Slave)
Comparator
TMR2
Comparator
PR2
(1)
RQ
S
Duty Cycle Registers DCxB<1:0>
Clear Timer2,
Toggle PWM Pin and
Latch Duty Cycle
Note 1: The 8-bit TMR2 register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler, to create the
10-bit time base.
2: The TRIS register value for each PWM output must be configured appropriately.
3: Any pin not used by an Enhanced PWM mode is available for alternate pin functions.
TRIS
(2)
ECCP1/Output Pi
n
(3)
TRIS
(2)
Output Pi
n
(3)
TRIS
(2)
Output Pi
n
(3)
TRIS
(2)
Output Pi
n
(3)
Output
Controller
PxM<1:0>
2
CCPxM<3:0>
4
ECCPxDEL
ECCPx/PxA
PxB
PxC
PxD
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TABLE 18-3: EXAMPLE PIN ASSIGNMENTS FOR VARIOUS PWM ENHANCED MODES
FIGURE 18-4: EXAMPLE PWM (ENHANCED MODE) OUTPUT RELATIONSHIPS
(ACTIVE-HIGH STATE)
ECCP Mode PxM<1:0> PxA PxB PxC PxD
Single 00 Yes(1)Yes (1)Yes(1)Yes(1)
Half-Bridge 10 Yes Yes No No
Full-Bridge, Forward 01 Yes Yes Yes Yes
Full-Bridge, Reverse 11 Yes Yes Ye s Ye s
Note 1: Outputs are enabled by pulse steering in Single mode (see Register 18-5).
0
Period
00
10
01
11
Signal PR2 + 1
PxM<1:0>
PxA Modulated
PxA Modulated
PxB Modulated
PxA Active
PxB Inactive
PxC Inactive
PxD Modulated
PxA Inactive
PxB Modulated
PxC Active
PxD Inactive
Pulse Width
(Single Output)
(Half-Bridge)
(Full-Bridge,
Forward)
(Full-Bridge,
Reverse)
Delay
(1)
Delay(1)
Relationships:
• Period = 4 * TOSC * (PR2 + 1) * (TMR2 Prescale Value)
• Pulse Width = TOSC * (CCPRxL<7:0>:CCPxCON<5:4>) * (TMR2 Prescale Value)
• Delay = 4 * T
OSC * (ECCPxDEL<6:0>)
Note 1: Dead-band delay is programmed using the ECCPxDEL register (Section 18.4.6 “Programmable Dead-Band
Delay Mode”).
2012 Microchip Technology Inc. DS30575A-page 325
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FIGURE 18-5: EXAMPLE ENHANCED PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE)
0
Period
00
10
01
11
Signal PR2 + 1
PxM<1:0>
PxA Modulated
PxA Modulated
PxB Modulated
PxA Active
PxB Inactive
PxC Inactive
PxD Modulated
PxA Inactive
PxB Modulated
PxC Active
PxD Inactive
Pulse
Width
(Single Output)
(Half-Bridge)
(Full-Bridge,
Forward)
(Full-Bridge,
Reverse)
Delay(1) Delay(1)
Relationships:
• Period = 4 * T
OSC * (PR2 + 1) * (TMR2 Prescale Value)
• Pulse Width = TOSC * (CCPRxL<7:0>:CCPxCON<5:4>) * (TMR2 Prescale Value)
• Delay = 4 * TOSC * (ECCPxDEL<6:0>)
Note 1: Dead-band delay is programmed using the ECCPxDEL register (Section 18.4.6 “Programmable Dead-Band
Delay Mode”).
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18.4.1 HALF-BRIDGE MODE
In Half-Bridge mode, two pins are used as outputs to
drive push-pull loads. The PWM output signal is output
on the PxA pin, while the complementary PWM output
signal is output on the PxB pin (see Figure 18-6). This
mode can be used for half-bridge applications, as
shown in Figure 18-7, or for full-bridge applications,
where four power switches are being modulated with
two PWM signals.
In Half-Bridge mode, the programmable dead-band delay
can be used to prevent shoot-through current in
half-bridge power devices. The value of the PxDC<6:0>
bits of the ECCPxDEL register sets the number of
instruction cycles before the output is driven active. If the
value is greater than the duty cycle, the corresponding
output remains inactive during the entire cycle. For more
details on the dead-band delay operations, see
Section 18.4.6 “Programmable Dead-Band Delay
Mode”.
Since the PxA and PxB outputs are multiplexed with the
PORT data latches, the associated TRIS bits must be
cleared to configure PxA and PxB as outputs.
FIGURE 18-6: EXAMPLE OF
HALF-BRIDGE PWM
OUTPUT
FIGURE 18-7: EXAMPLE OF HALF-BRIDGE APPLICATIONS
Period
Pulse Width
td
td
(1)
PxA(2)
PxB(2)
td = Dead-Band Delay
Period
(1) (1)
Note 1: At this time, the TMR2 register is equal to the
PR2 register.
2: Output signals are shown as active-high.
PxA
PxB
FET
Driver
FET
Driver
Load
+
-
+
-
FET
Driver
FET
Driver
V+
Load
FET
Driver
FET
Driver
PxA
PxB
Standard Half-Bridge Circuit (“Push-Pull”)
Half-Bridge Output Driving a Full-Bridge Circuit
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18.4.2 FULL-BRIDGE MODE
In Full-Bridge mode, all four pins are used as outputs.
An example of a full-bridge application is provided in
Figure 18-8.
In the Forward mode, the PxA pin is driven to its active
state and the PxD pin is modulated, while the PxB and
PxC pins are driven to their inactive state, as provided in
Figure 18-9.
In the Reverse mode, the PxC pin is driven to its active
state and the PxB pin is modulated, while the PxA and
PxD pins are driven to their inactive state, as provided in
Figure 18-9.
The PxA, PxB, PxC and PxD outputs are multiplexed
with the port data latches. The associated TRIS bits
must be cleared to configure the PxA, PxB, PxC and
PxD pins as outputs.
FIGURE 18-8: EXAMPLE OF FULL-BRIDGE APPLICATION
PxA
PxC
FET
Driver
FET
Driver
V+
V-
Load
FET
Driver
FET
Driver
PxB
PxD
QA
QB QD
QC
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FIGURE 18-9: EXAMPLE OF FULL-BRIDGE PWM OUTPUT
Period
Pulse Width
PxA(2)
PxB(2)
PxC(2)
PxD(2)
Forward Mode
(1)
Period
Pulse Width
PxA(2)
PxC(2)
PxD(2)
PxB(2)
Reverse Mode
(1)
(1)
(1)
Note 1: At this time, the TMR2 register is equal to the PR2 register.
2: The output signal is shown as active-high.
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18.4.2.1 Direction Change in Full-Bridge
Mode
In Full-Bridge mode, the PxM1 bit in the CCPxCON
register allows users to control the forward/reverse
direction. When the application firmware changes this
direction control bit, the module will change to the new
direction on the next PWM cycle.
A direction change is initiated in software by changing
the PxM1 bit of the CCPxCON register. The following
sequence occurs prior to the end of the current PWM
period:
• The modulated outputs (PxB and PxD) are placed
in their inactive state.
• The associated unmodulated outputs (PxA and
PxC) are switched to drive in the opposite
direction.
• PWM modulation resumes at the beginning of the
next period.
For an illustration of this sequence, see Figure 18-10.
The Full-Bridge mode does not provide a dead-band
delay. As one output is modulated at a time, a
dead-band delay is generally not required. There is a
situation where a dead-band delay is required. This
situation occurs when both of the following conditions
are true:
• The direction of the PWM output changes when
the duty cycle of the output is at or near 100%.
• The turn-off time of the power switch, including
the power device and driver circuit, is greater than
the turn-on time.
Figure 18-11 shows an example of the PWM direction
changing from forward to reverse, at a near 100% duty
cycle. In this example, at time, t1, the PxA and PxD
outputs become inactive, while the PxC output
becomes active. Since the turn-off time of the power
devices is longer than the turn-on time, a shoot-through
current will flow through power devices, QC and QD
(see Figure 18-8), for the duration of ‘t’. The same
phenomenon will occur to power devices, QA and QB,
for PWM direction change from reverse to forward.
If changing PWM direction at high duty cycle is required
for an application, two possible solutions for eliminating
the shoot-through current are:
• Reduce PWM duty cycle for one PWM period
before changing directions.
• Use switch drivers that can drive the switches off
faster than they can drive them on.
Other options to prevent shoot-through current may
exist.
FIGURE 18-10: EXAMPLE OF PWM DIRECTION CHANGE
Pulse Width
Period(1)
Signal
Note 1: The direction bit, PxM1 of the CCPxCON register, is written any time during the PWM cycle.
2: When changing directions, the PxA and PxC signals switch before the end of the current PWM cycle. The
modulated PxB and PxD signals are inactive at this time. The length of this time is: (1/FOSC) • TMR2 Prescale Value.
Period
(2)
PxA (Active-High)
PxB (Active-High)
PxC (Active-High)
PxD (Active-High)
Pulse Width
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FIGURE 18-11: EXAMPLE OF PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE
18.4.3 START-UP CONSIDERATIONS
When any PWM mode is used, the application
hardware must use the proper external pull-up and/or
pull-down resistors on the PWM output pins.
The CCPxM<1:0> bits of the CCPxCON register allow
the user to choose whether the PWM output signals are
active-high or active-low for each pair of PWM output
pins (PxA/PxC and PxB/PxD). The PWM output
polarities must be selected before the PWM pin output
drivers are enabled. Changing the polarity configura-
tion while the PWM pin output drivers are enabled is
not recommended since it may result in damage to the
application circuits.
The PxA, PxB, PxC and PxD output latches may not be
in the proper states when the PWM module is
initialized. Enabling the PWM pin output drivers, at the
same time as the Enhanced PWM modes, may cause
damage to the application circuit. The Enhanced PWM
modes must be enabled in the proper Output mode and
complete a full PWM cycle before enabling the PWM
pin output drivers. The completion of a full PWM cycle
is indicated by the TMR2IF or TMR4IF bit of the PIR1
or PIR5 register being set as the second PWM period
begins.
18.4.4 ENHANCED PWM
AUTO-SHUTDOWN MODE
The PWM mode supports an Auto-Shutdown mode that
will disable the PWM outputs when an external
shutdown event occurs. Auto-Shutdown mode places
the PWM output pins into a predetermined state. This
mode is used to help prevent the PWM from damaging
the application.
The auto-shutdown sources are selected using the
ECCPxAS<2:0> bits (ECCPxAS<6:4>). A shutdown
event may be generated by:
• A logic ‘0’ on the pin that is assigned the FLT0
input function
• Comparator C1
• Comparator C2
• Setting the ECCPxASE bit in firmware
A shutdown condition is indicated by the ECCPxASE
(Auto-Shutdown Event Status) bit (ECCPxAS<7>). If
the bit is a ‘0’, the PWM pins are operating normally. If
the bit is a ‘1’, the PWM outputs are in the shutdown
state.
Forward Period Reverse Period
PxA
TON
TOFF
T = TOFF – TON
PxB
PxC
PxD
External Switch D
Potential
Shoot-Through Current
Note 1: All signals are shown as active-high.
2: TON is the turn-on delay of power switch QC and its driver.
3: TOFF is the turn-off delay of power switch QD and its driver.
External Switch C
t1
PW
PW
Note: When the microcontroller is released from
Reset, all of the I/O pins are in the
high-impedance state. The external circuits
must keep the power switch devices in the
OFF state until the microcontroller drives
the I/O pins with the proper signal levels or
activates the PWM output(s).
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When a shutdown event occurs, two things happen:
• The ECCPxASE bit is set to ‘1’. The ECCPxASE
will remain set until cleared in firmware or an
auto-restart occurs. (See Section 18.4.5
“Auto-Restart Mode”.)
• The enabled PWM pins are asynchronously
placed in their shutdown states. The PWM output
pins are grouped into pairs (PxA/PxC and
PxB/PxD). The state of each pin pair is
determined by the PSSxAC and PSSxBD bits
(ECCPxAS<3:2> and <1:0>, respectively).
Each pin pair may be placed into one of three states:
• Drive logic ‘1’
• Drive logic ‘0’
• Tri-state (high-impedance)
REGISTER 18-3: ECCPxAS: ECCPx AUTO-SHUTDOWN CONTROL REGISTER(1,2,3)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ECCPxASE ECCPxAS2 ECCPxAS1 ECCPxAS0 PSSxAC1 PSSxAC0 PSSxBD1 PSSxBD0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ECCPxASE: ECCP Auto-Shutdown Event Status bit
1 = A shutdown event has occurred; ECCP outputs are in a shutdown state
0 = ECCP outputs are operating
bit 6-4 ECCPxAS<2:0>: ECCP Auto-Shutdown Source Select bits
000 = Auto-shutdown is disabled
001 = Comparator C1OUT output is high
010 = Comparator C2OUT output is high
011 = Either Comparator C1OUT or C2OUT is high
100 =V
IL on FLT0 pin
101 =V
IL on FLT0 pin or Comparator C1OUT output is high
110 =V
IL on FLT0 pin or Comparator C2OUT output is high
111 =V
IL on FLT0 pin or Comparator C1OUT or Comparator C2OUT is high
bit 3-2 PSSxAC<1:0>: PxA and PxC Pins Shutdown State Control bits
00 = Drive pins: PxA and PxC to ‘0’
01 = Drive pins: PxA and PxC to ‘1’
1x = PxA and PxC pins tri-state
bit 1-0 PSSxBD<1:0>: Pins PxB and PxD Shutdown State Control bits
00 = Drive pins: PxB and PxD to ‘0’
01 = Drive pins: PxB and PxD to ‘1’
1x = PxB and PxD pins tri-state
Note 1: The auto-shutdown condition is a level-based signal, not an edge-based signal. As long as the level is
present, the auto-shutdown will persist.
2: Writing to the ECCPxASE bit is disabled while an auto-shutdown condition persists.
3: Once the auto-shutdown condition has been removed and the PWM restarted (either through firmware or
auto-restart), the PWM signal will always restart at the beginning of the next PWM period.
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FIGURE 18-12: PWM AUTO-SHUTDOWN WITH FIRMWARE RESTART (PxRSEN = 0)
18.4.5 AUTO-RESTART MODE
The Enhanced PWM can be configured to automatically
restart the PWM signal once the auto-shutdown condi-
tion has been removed. Auto-restart is enabled by
setting the PxRSEN bit (ECCPxDEL<7>).
If auto-restart is enabled, the ECCPxASE bit will
remain set as long as the auto-shutdown condition is
active. When the auto-shutdown condition is removed,
the ECCPxASE bit will be cleared via hardware and
normal operation will resume.
The module will wait until the next PWM period begins,
however, before re-enabling the output pin. This behav-
ior allows the auto-shutdown with auto-restart features
to be used in applications based on current mode of
PWM control.
FIGURE 18-13: PWM AUTO-SHUTDOWN WITH AUTO-RESTART ENABLED (PxRSEN = 1)
Shutdown
PWM
ECCPxASE bit
Activity
Event
Shutdown
Event Occurs
Shutdown
Event Clears
PWM
Resumes
Normal PWM
Start of
PWM Period
ECCPxASE
Cleared by
Firmware
PWM Period
Cleared by
Shutdown
PWM
ECCPxASE bit
Activity
Event
Shutdown
Event Occurs
Shutdown
Event Clears
PWM
Resumes
Normal PWM
Start of
PWM Period
PWM Period
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18.4.6 PROGRAMMABLE DEAD-BAND
DELAY MODE
In half-bridge applications, where all power switches are
modulated at the PWM frequency, the power switches
normally require more time to turn off than to turn on. If
both the upper and lower power switches are switched
at the same time (one turned on and the other turned
off), both switches may be on for a short period until one
switch completely turns off. During this brief interval, a
very high current (shoot-through current) will flow
through both power switches, shorting the bridge supply.
To avoid this potentially destructive shoot-through
current from flowing during switching, turning on either of
the power switches is normally delayed to allow the
other switch to completely turn off.
In Half-Bridge mode, a digitally programmable
dead-band delay is available to avoid shoot-through
current from destroying the bridge power switches. The
delay occurs at the signal transition from the non-active
state to the active state. For an illustration, see
Figure 18-14. The lower seven bits of the associated
ECCPxDEL register (Register 18-4) set the delay
period in terms of microcontroller instruction cycles
(T
CY or 4 TOSC).
FIGURE 18-14: EXAMPLE OF
HALF-BRIDGE PWM
OUTPUT
FIGURE 18-15: EXAMPLE OF HALF-BRIDGE APPLICATIONS
Period
Pulse Width
td
td
(1)
PxA(2)
PxB(2)
td = Dead-Band Delay
Period
(1) (1)
Note 1: At this time, the TMR2 register is equal to the
PR2 register.
2: Output signals are shown as active-high.
PxA
PxB
FET
Driver
FET
Driver
V+
V-
Load
+
V
-
+
V
-
Standard Half-Bridge Circuit (“Push-Pull”)
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18.4.7 PULSE STEERING MODE
In Single Output mode, pulse steering allows any of the
PWM pins to be the modulated signal. Additionally, the
same PWM signal can simultaneously be available on
multiple pins.
Once the Single Output mode is selected
(CCPxM<3:2> = 11 and PxM<1:0> = 00 of the
CCPxCON register), the user firmware can bring out
the same PWM signal to one, two, three or four output
pins by setting the appropriate STR<D:A> bits
(PSTRxCON<3:0>), as provided in Table 18-3.
While the PWM Steering mode is active, the
CCPxM<1:0> bits (CCPxCON<1:0>) select the PWM
output polarity for the Px<D:A> pins.
The PWM auto-shutdown operation also applies to the
PWM Steering mode, as described in Section 18.4.4
“Enhanced PWM Auto-shutdown mode”. An
auto-shutdown event will only affect pins that have
PWM outputs enabled.
REGISTER 18-4: ECCPxDEL: ENHANCED PWM CONTROL REGISTER x
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
PxRSEN PxDC6 PxDC5 PxDC4 PxDC3 PxDC2 PxDC1 PxDC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 PxRSEN: PWM Restart Enable bit
1 = Upon auto-shutdown, the ECCPxASE bit clears automatically once the shutdown event goes
away; the PWM restarts automatically
0 = Upon auto-shutdown, ECCPxASE must be cleared by software to restart the PWM
bit 6-0 PxDC<6:0>: PWM Delay Count bits
PxDCn = Number of FOSC/4 (4 * TOSC) cycles between the scheduled time when a PWM signal
should transition active and the actual time it does transition active.
Note: The associated TRIS bits must be set to
output (‘0’) to enable the pin output driver
in order to see the PWM signal on the pin.
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REGISTER 18-5: PSTRxCON: PULSE STEERING CONTROL(1)
R/W-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-1
CMPL1 CMPL0 — STRSYNC STRD STRC STRB STRA
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 CMPL<1:0>: Complementary Mode Output Assignment Steering Sync bits
00 = See STR<D:A>
01 = PA and PB are selected as the complementary output pair
10 = PA and PC are selected as the complementary output pair
11 = PA and PD are selected as the complementary output pair
bit 5 Unimplemented: Read as ‘0’
bit 4 STRSYNC: Steering Sync bit
1 = Output steering update occurs on the next PWM period
0 = Output steering update occurs at the beginning of the instruction cycle boundary
bit 3 STRD: Steering Enable bit D
1 = PxD pin has the PWM waveform with polarity control from CCPxM<1:0>
0 = PxD pin is assigned to port pin
bit 2 STRC: Steering Enable bit C
1 = PxC pin has the PWM waveform with polarity control from CCPxM<1:0>
0 = PxC pin is assigned to port pin
bit 1 STRB: Steering Enable bit B
1 = PxB pin has the PWM waveform with polarity control from CCPxM<1:0>
0 = PxB pin is assigned to port pin
bit 0 STRA: Steering Enable bit A
1 = PxA pin has the PWM waveform with polarity control from CCPxM<1:0>
0 = PxA pin is assigned to port pin
Note 1: The PWM Steering mode is available only when the CCPxCON register bits, CCPxM<3:2> = 11 and
PxM<1:0> = 00.
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FIGURE 18-16: SIMPLIFIED STEERING
BLOCK DIAGRAM
18.4.7.1 Steering Synchronization
The STRSYNC bit of the PSTRxCON register gives the
user two choices for when the steering event will
happen. When the STRSYNC bit is ‘0’, the steering
event will happen at the end of the instruction that
writes to the PSTRxCON register. In this case, the out-
put signal at the Px<D:A> pins may be an incomplete
PWM waveform. This operation is useful when the user
firmware needs to immediately remove a PWM signal
from the pin.
When the STRSYNC bit is ‘1’, the effective steering
update will happen at the beginning of the next PWM
period. In this case, steering on/off the PWM output will
always produce a complete PWM waveform.
Figures 18-17 and 18-18 illustrate the timing diagrams
of the PWM steering depending on the STRSYNC
setting.
FIGURE 18-17: EXAMPLE OF STEERING EVENT AT END OF INSTRUCTION (STRSYNC = 0)
FIGURE 18-18: EXAMPLE OF STEERING EVENT AT BEGINNING OF INSTRUCTION (STRSYNC = 1)
1
0TRIS
Output Pin(1)
PORT Data
PxA Signal
STRA(2)
1
0
TRIS
Output Pin(1)
PORT Data
STRB(2)
1
0
TRIS
Output Pin(1)
PORT Data
STRC(2)
1
0TRIS
Output Pin(1)
PORT Data
STRD(2)
Note 1: Port outputs are configured as displayed when
the CCPxCON register bits, PxM<1:0> = 00
and CCPxM<3:2> = 11.
2: Single PWM output requires setting at least
one of the STRx bits.
CCPxM1
CCPxM0
CCPxM1
CCPxM0
PWM
P1n = PWM
STRn
P1<D:A> PORT Data
PWM Period
PORT Data
PWM
PORT Data
P1n = PWM
STRn
P1<D:A> PORT Data
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18.4.8 OPERATION IN POWER-MANAGED
MODES
In Sleep mode, all clock sources are disabled.
Timer2/4/6/8 will not increment and the state of the
module will not change. If the ECCPx pin is driving a
value, it will continue to drive that value. When the
device wakes up, it will continue from this state. If
Two-Speed Start-ups are enabled, the initial start-up
frequency from HF-INTOSC and the postscaler may
not be stable immediately.
In PRI_IDLE mode, the primary clock will continue to
clock the ECCPx module without change.
18.4.8.1 Operation with Fail-Safe
Clock Monitor (FSCM)
If the Fail-Safe Clock Monitor (FSCM) is enabled, a clock
failure will force the device into the power-managed
RC_RUN mode and the OSCFIF bit of the PIR2 register
will be set. The ECCPx will then be clocked from the
internal oscillator clock source, which may have a
different clock frequency than the primary clock.
18.4.9 EFFECTS OF A RESET
Both Power-on Reset and subsequent Resets will force
all ports to Input mode and the ECCP registers to their
Reset states.
This forces the ECCP module to reset to a state
compatible with previous, non-enhanced CCP modules
used on other PIC18 and PIC16 devices.
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NOTES:
2012 Microchip Technology Inc. DS30575A-page 339
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19.0 CAPTURE/COMPARE/PWM
(CCP) MODULES
PIC18F97J94 family devices have seven CCP
(Capture/Compare/PWM) modules, designated CCP4
through CCP10. All the modules implement standard
Capture, Compare and Pulse-Width Modulation (PWM)
modes.
Each CCP module contains a 16-bit register that can
operate as a 16-bit Capture register, a 16-bit Compare
register or a PWM Master/Slave Duty Cycle register.
For the sake of clarity, all CCP module operation in the
following sections is described with respect to CCP4,
but is equally applicable to CCP5 through CCP10.
Note: Throughout this section, generic references
are used for register and bit names that are
the same, except for an ‘x’ variable that indi-
cates the item’s association with the specific
CCP module. For example, the control
register is named CCPxCON and refers to
CCP4CON through CCP10CON.
REGISTER 19-1: CCPxCON: CCPx CONTROL REGISTER (CCP4-CCP10 MODULES)
U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
—— DCxB1 DCxB0 CCPxM3(1)CCPxM2(1)CCPxM1(1)CCPxM0(1)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 Unimplemented: Read as ‘0’
bit 5-4 DCxB<1:0>: PWM Duty Cycle bit 1 and bit 0 for CCPx module bits
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two Least Significant bits (bit 1 and bit 0) of the 10-bit PWM duty cycle. The eight
Most Significant bits (DCx<9:2>) of the duty cycle are found in CCPRxL.
bit 3-0 CCPxM<3:0>: CCPx Module Mode Select bits(1)
0000 = Capture/Compare/PWM is disabled (resets CCPx module)
0001 = Reserved
0010 = Compare mode, toggles output on match (CCPxIF bit is set)
0011 = Reserved
0100 = Capture mode: Every falling edge
0101 = Capture mode: Every rising edge
0110 = Capture mode: Every 4th rising edge
0111 = Capture mode: Every 16th rising edge
1000 = Compare mode: Initialize CCPx pin low; on compare match, force CCPx pin high (CCPxIF bit is set)
1001 = Compare mode: Initialize CCPx pin high; on compare match, force CCPx pin low (CCPxIF bit is set)
1010 = Compare mode: Generate software interrupt on compare match (CCPxIF bit is set, CCPx pin
reflects I/O state)
1011 = Compare mode: Special Event Trigger; reset timer on CCPx match (CCPxIF bit is set)
11xx =PWM mode
Note 1: CCPxM<3:0> = 1011 will only reset the timer and not start an A/D conversion on a CCPx match.
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REGISTER 19-2: CCPTMRS1: CCP TIMER SELECT REGISTER 1
R/W-0 R/W-0 U-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0
C7TSEL1 C7TSEL0 — C6TSEL0 — C5TSEL0 C4TSEL1 C4TSEL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 C7TSEL<1:0>: CCP7 Timer Selection bits
00 = CCP7 is based off of TMR1/TMR2
01 = CCP7 is based off of TMR5/TMR4
10 = CCP7 is based off of TMR5/TMR6
11 = CCP7 is based off of TMR5/TMR8
bit 5 Unimplemented: Read as ‘0’
bit 4 C6TSEL0: CCP6 Timer Selection bit
0 = CCP6 is based off of TMR1/TMR2
1 = CCP6 is based off of TMR5/TMR2
bit 3 Unimplemented: Read as ‘0’
bit 2 C5TSEL0: CCP5 Timer Selection bit
0 = CCP5 is based off of TMR1/TMR2
1 = CCP5 is based off of TMR5/TMR4
bit 1-0 C4TSEL<1:0>: CCP4 Timer Selection bits
00 = CCP4 is based off of TMR1/TMR2
01 = CCP4 is based off of TMR3/TMR4
10 = CCP4 is based off of TMR3/TMR6
11 = Reserved; do not use
2012 Microchip Technology Inc. DS30575A-page 341
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REGISTER 19-3: CCPTMRS2: CCP TIMER SELECT REGISTER 2
U-0 U-0 U-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0
— — — C10TSEL0 — C9TSEL0 C8TSEL1 C8TSEL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘0’
bit 4 C10TSEL0: CCP10 Timer Selection bit
0 = CCP10 is based off of TMR1/TMR2
1 = CCP10 is based off of TMR5/TMR2
bit 3 Unimplemented: Read as ‘0’
bit 2 C9TSEL0: CCP9 Timer Selection bit
0 = CCP9 is based off of TMR1/TMR2
1 = CCP9 is based off of TMR5/TMR4
bit 1-0 C8TSEL<1:0>: CCP8 Timer Selection bits
00 = CCP8 is based off of TMR1/TMR2
01 = CCP8 is based off of TMR3/TMR4
10 = CCP8 is based off of TMR3/TMR6
11 = Reserved; do not use
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REGISTER 19-4: CCPRxL: CCPx PERIOD LOW BYTE REGISTER
R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
CCPRxL7 CCPRxL6 CCPRxL5 CCPRxL4 CCPRxL3 CCPRxL2 CCPRxL1 CCPRxL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CCPRxL<7:0>: CCPx Period Register Low Byte bits
Capture mode: Capture Register Low Byte
Compare mode: Compare Register Low Byte
PWM mode: Duty Cycle Register
REGISTER 19-5: CCPRxH: CCPx PERIOD HIGH BYTE REGISTER
R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
CCPRxH7 CCPRxH6 CCPRxH5 CCPRxH4 CCPRxH3 CCPRxH2 CCPRxH1 CCPRxH0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CCPRxH<7:0>: CCPx Period Register High Byte bits
Capture mode: Capture Register High Byte
Compare mode: Compare Register High Byte
PWM mode: Duty Cycle Buffer Register
2012 Microchip Technology Inc. DS30575A-page 343
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19.1 CCP Module Configuration
Each Capture/Compare/PWM module is associated
with a control register (generically, CCPxCON) and a
data register (CCPRx). The data register, in turn, is
comprised of two 8-bit registers: CCPRxL (low byte)
and CCPRxH (high byte). All registers are both
readable and writable.
19.1.1 CCP MODULES AND TIMER
RESOURCES
The CCP modules utilize Timers, 1 through 8, that vary
with the selected mode. Various timers are available to
the CCP modules in Capture, Compare or PWM
modes, as shown in Table 19-1.
TABLE 19-1: CCP MODE – TIMER
RESOURCE
The assignment of a particular timer to a module is
determined by the timer to CCP enable bits in the
CCPTMRSx registers. (See Register 19-2 and
Register 19-3.) All of the modules may be active at
once and may share the same timer resource if they
are configured to operate in the same mode
(Capture/Compare or PWM) at the same time.
The CCPTMRS1 register selects the timers for CCP
modules, 7, 6, 5 and 4, and the CCPTMRS2 register
selects the timers for CCP modules, 10, 9 and 8. The
possible configurations are shown in Ta bl e 1 9 - 2 and
Table 19-3.
TABLE 19-2: TIMER ASSIGNMENTS FOR CCP MODULES 4, 5, 6 AND 7
TABLE 19-3: TIMER ASSIGNMENTS FOR CCP MODULES 8, 9 AND 10
CCP Mode Timer Resource
Capture
Timer1, Timer3 or Timer 5
Compare
PWM Timer2, Timer4, Timer 6 or Timer8
CCPTMRS1 Register
CCP4 CCP5 CCP6 CCP7
C4TSEL
<1:0>
Capture/
Compare
Mode
PWM
Mode C5TSEL0
Capture/
Compare
Mode
PWM
Mode C6TSEL0
Capture/
Compare
Mode
PWM
Mode
C7TSEL
<1:0>
Capture/
Compare
Mode
PWM
Mode
00 TMR1 TMR2 0TMR1 TMR2 0TMR1 TMR2 00 TMR1 TMR2
01 TMR3 TMR4 1TMR5 TMR4 1TMR5 TMR2 01 TMR5 TMR4
10 TMR3 TMR6 10 TMR5 TMR6
11 Reserved(1)11 TMR5 TMR8
Note 1: Do not use the reserved bits.
CCPTMRS2 Register
CCP8 CCP8
Devices with 32 Kbytes CCP9 CCP10
C8TSEL
<1:0>
Capture/
Compare
Mode
PWM
Mode
C8TSEL
<1:0>
Capture/
Compare
Mode
PWM
Mode C9TSEL0
Capture/
Compare
Mode
PWM
Mode C10TSEL0
Capture/
Compare
Mode
PWM
Mode
00
TMR1 TMR2
00
TMR1 TMR2
0
TMR1 TMR2
0
TMR1 TMR2
01
TMR5 TMR4
01
TMR1 TMR4
1
TMR5 TMR4
1
TMR5 TMR2
10
TMR5 TMR6
10
TMR1 TMR6
11
Reserved
(1)
11
Reserved
(1)
Note 1: Do not use the reserved bits.
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DS30575A-page 344 2012 Microchip Technology Inc.
19.1.2 OPEN-DRAIN OUTPUT OPTION
When operating in Output mode (the Compare or PWM
modes), the drivers for the CCPx pins can be optionally
configured as open-drain outputs. This feature allows
the voltage level on the pin to be pulled to a higher level
through an external pull-up resistor and allows the
output to communicate with external circuits without the
need for additional level shifters.
The open-drain output option is controlled by the
CCPxOD bits (ODCON2<7:1>). Setting the appropri-
ate bit configures the pin for the corresponding module
for open-drain operation.
19.2 Capture Mode
In Capture mode, the CCPR4H:CCPR4L register pair
captures the 16-bit value of the Timer register selected
in the CCPTMRS1 when an event occurs on the CCP4
pin. An event is defined as one of the following:
• Every falling edge
• Every rising edge
• Every 4th rising edge
• Every 16th rising edge
The event is selected by the mode select bits,
CCP4M<3:0> (CCP4CON<3:0>). When a capture is
made, the interrupt request flag bit, CCP4IF (PIR4<1>),
is set. (It must be cleared in software.) If another
capture occurs before the value in CCPR4 is read, the
old captured value is overwritten by the new captured
value.
Figure 19-1 shows the Capture mode block diagram.
19.2.1 CCP PIN CONFIGURATION
In Capture mode, the appropriate CCPx pin should be
configured as an input by setting the corresponding
TRIS direction bit.
19.2.2 TIMER1/3/5/7 MODE SELECTION
For the available timers (1/3/5) to be used for the capture
feature, the used timers must be running in Timer mode
or Synchronized Counter mode. In Asynchronous
Counter mode, the capture operation will not work.
The timer to be used with each CCP module is selected
in the CCPTMRSx registers. (See Section 19.1.1 “CCP
Modules and Timer Resources”.)
Details of the timer assignments for the CCP modules
are given in Table 19-2 and Table 19-3.
Note: If the CCPx pin is configured as an output,
a write to the port can cause a capture
condition.
2012 Microchip Technology Inc. DS30575A-page 345
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FIGURE 19-1: CAPTURE MODE OPERATION BLOCK DIAGRAM
19.2.3 SOFTWARE INTERRUPT
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep the
CCP4IE bit (PIE4<1>) clear to avoid false interrupts
and should clear the flag bit, CCP4IF, following any
such change in operating mode.
19.2.4 CCP PRESCALER
There are four prescaler settings in Capture mode.
They are specified as part of the operating mode
selected by the mode select bits (CCP4M<3:0>).
Whenever the CCP module is turned off, or the CCP
module is not in Capture mode, the prescaler counter
is cleared. This means that any Reset will clear the
prescaler counter.
Switching from one capture prescaler to another may
generate an interrupt. Doing that will also not clear the
prescaler counter – meaning the first capture may be
from a non-zero prescaler.
Example 19-1 shows the recommended method for
switching between capture prescalers. This example
also clears the prescaler counter and will not generate
the “false” interrupt.
EXAMPLE 19-1: CHANGING BETWEEN
CAPTURE PRESCALERS
CCPR5H CCPR5L
TMR1H TMR1L
Set CCP5IF
TMR5
Enable
Q1:Q4
CCP5CON<3:0>
CCP5 Pin
Prescaler
1, 4, 16
and
Edge Detect
TMR1
Enable
C5TSEL0
C5TSEL0
CCPR4H CCPR4L
TMR1H TMR1L
Set CCP4IF
TMR3
Enable
CCP4CON<3:0>
CCP4 Pin
Prescaler
1, 4, 16
TMR3H TMR3L
TMR1
Enable
C4TSEL0
C4TSEL1
C4TSEL0
C4TSEL1
TMR5H TMR5L
and
Edge Detect
4
4
4
Note: This block diagram uses CCP4 and CCP5, and their appropriate timers as an example. For details on all of
the CCP modules and their timer assignments, see Table 19-2 and Table 19-3.
CLRF CCP4CON ; Turn CCP module off
MOVLW NEW_CAPT_PS ; Load WREG with the
; new prescaler mode
; value and CCP ON
MOVWF CCP4CON ; Load CCP4CON with
; this value
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DS30575A-page 346 2012 Microchip Technology Inc.
19.3 Compare Mode
In Compare mode, the 16-bit CCPR4 register value is
constantly compared against the Timer register pair
value selected in the CCPTMR1 register. When a
match occurs, the CCP4 pin can be:
• Driven high
•Driven low
• Toggled (high-to-low or low-to-high)
• Unchanged (that is, reflecting the state of the I/O
latch)
The action on the pin is based on the value of the mode
select bits (CCP4M<3:0>). At the same time, the
interrupt flag bit, CCP4IF, is set.
Figure 19-2 gives the Compare mode block diagram
19.3.1 CCP PIN CONFIGURATION
The user must configure the CCPx pin as an output by
clearing the appropriate TRIS bit.
19.3.2 TIMER1/3/5 MODE SELECTION
If the CCP module is using the compare feature in
conjunction with any of the Timer1/3/5 timers, the
timers must be running in Timer mode or Synchronized
Counter mode. In Asynchronous Counter mode, the
compare operation will not work.
19.3.3 SOFTWARE INTERRUPT MODE
When the Generate Software Interrupt mode is chosen
(CCP4M<3:0> = 1010), the CCP4 pin is not affected.
Only a CCP interrupt is generated, if enabled, and the
CCP4IE bit is set.
19.3.4 SPECIAL EVENT TRIGGER
Both CCP modules are equipped with a Special Event
Trigger. This is an internal hardware signal, generated
in Compare mode, to trigger actions by other modules.
The Special Event Trigger is enabled by selecting
the Compare Special Event Trigger mode
(CCP4M<3:0> = 1011).
For either CCP module, the Special Event Trigger resets
the Timer register pair for whichever timer resource is
currently assigned as the module’s time base. This
allows the CCPRx registers to serve as a Programmable
Period register for either timer.
The Special Event Trigger for CCP4 cannot start an
A/D conversion.
Note: Clearing the CCPxCON register will force
the CCPx compare output latch (depend-
ing on device configuration) to the default
low level. This is not the PORTx I/O data
latch.
Note: Details of the timer assignments for the
CCP modules are given in Table 19-2 and
Ta b l e 1 9 - 3 .
2012 Microchip Technology Inc. DS30575A-page 347
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FIGURE 19-2: COMPARE MODE OPERATION BLOCK DIAGRAM
CCPR5H CCPR5L
TMR1H TMR1L
Comparator QS
R
Output
Logic
Special Event Trigger
Set CCP5IF
CCP5 Pin
TRIS
CCP5CON<3:0>
Output Enable
TMR5H TMR5L 1
0
Compare
4
(Timer1/5 Reset)
Match
Note: This block diagram uses CCP4 and CCP5 and their appropriate timers as an example. For details on all of
the CCP modules and their timer assignments, see Table 19-2 and Table 19-3.
TMR1H TMR1L
TMR3H TMR3L
CCPR4H CCPR4L
Comparator
C4TSEL1
Set CCP4IF
1
0
QS
R
Output
Logic
Special Event Trigger
CCP4 Pin
TRIS
CCP4CON<3:0>
Output Enable
4
(Timer1/Timer3 Reset)
Compare
Match
C5TSEL0
C4TSEL0
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DS30575A-page 348 2012 Microchip Technology Inc.
19.4 PWM Mode
In Pulse-Width Modulation (PWM) mode, the CCP4 pin
produces up to a 10-bit resolution PWM output. Since
the CCP4 pin is multiplexed with a PORTC or PORTE
data latch, the appropriate TRIS bit must be cleared to
make the CCP4 pin an output.
Figure 19-3 shows a simplified block diagram of the
CCP4 module in PWM mode.
For a step-by-step procedure on how to set up the CCP
module for PWM operation, see Section 19.4.3
“Setup for PWM Operation”.
FIGURE 19-3: SIMPLIFIED PWM BLOCK
DIAGRAM
A PWM output (Figure 19-4) has a time base (period)
and a time that the output stays high (duty cycle). The
frequency of the PWM is the inverse of the period
(1/period).
FIGURE 19-4: PWM OUTPUT
19.4.1 PWM PERIOD
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following formula:
EQUATION 19-1: PWM PERIOD
CALCULATION
PWM frequency is defined as 1/[PWM period].
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
•TMR2 is cleared
• The CCP4 pin is set
(An exception: If PWM Duty Cycle = 0%, the
CCP4 pin will not be set)
• The PWM duty cycle is latched from CCPR4L into
CCPR4H
Note: Clearing the CCPxCON register will force
the CCPx compare output latch (depend-
ing on device configuration) to the default
low level. This is not the PORTx I/O data
latch.
CCPR4L
CCPR4H (Slave)
Comparator
TMR2
Comparator
PR2
(Note 1)
RQ
S
Duty Cycle Registers CCP4CON<5:4>
Clear Timer,
CCP4 Pin and
Latch D.C.
TRISC<2>
RC2/CCP4
Note 1: The 8-bit TMR2 value is concatenated with the 2-bit
internal Q clock, or 2 bits of the prescaler, to create the
10-bit time base.
2: CCP4 and its appropriate timers are used as an
example. For details on all of the CCP modules and
their timer assignments, see Table 19-2 and Table 19-3.
Note: The Timer2 postscalers (see
Section 16.0 “Timer2/4/6/8 Modules”)
are not used in the determination of the
PWM frequency. The postscaler could be
used to have a servo update rate at a dif-
ferent frequency than the PWM output.
Period
Duty Cycle
TMR2 = PR2
TMR2 = Duty Cycle
TMR2 = PR2
PWM Period = [(PR2) + 1] • 4 • TOSC •
(TMR2 Prescale Value)
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19.4.2 PWM DUTY CYCLE
The PWM duty cycle is specified, to use CCP4 as an
example, by writing to the CCPR4L register and to the
CCP4CON<5:4> bits. Up to 10-bit resolution is avail-
able. The CCPR4L contains the eight MSbs and the
CCP4CON<5:4> contains the two LSbs. This 10-bit
value is represented by CCPR4L:CCP4CON<5:4>.
The following equation is used to calculate the PWM
duty cycle in time:
EQUATION 19-2: PWM DUTY CYCLE
(IN TIME)
CCPR4L and CCP4CON<5:4> can be written to at any
time, but the duty cycle value is not latched into
CCPR4H until after a match between PR2 and TMR2
occurs (that is, the period is complete). In PWM mode,
CCPR4H is a read-only register.
The CCPR4H register and a two-bit internal latch are
used to double-buffer the PWM duty cycle. This
double-buffering is essential for glitchless PWM
operation.
When the CCPR4H and two-bit latch match TMR2,
concatenated with an internal two-bit Q clock or two
bits of the TMR2 prescaler, the CCP4 pin is cleared.
The maximum PWM resolution (bits) for a given PWM
frequency is given by the equation:
EQUATION 19-3: PWM RESOLUTION
TABLE 19-4: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
19.4.3 SETUP FOR PWM OPERATION
To configure the CCP module for PWM operation using
CCP4 as an example:
1. Set the PWM period by writing to the PR2
register.
2. Set the PWM duty cycle by writing to the
CCPR4L register and CCP4CON<5:4> bits.
3. Make the CCP4 pin an output by clearing the
appropriate TRIS bit.
4. Set the TMR2 prescale value, then enable
Timer2 by writing to T2CON.
5. Configure the CCP4 module for PWM operation.
PWM Duty Cycle = (CCPR4L:CCP4CON<5:4>) •
TOSC • (TMR2 Prescale Value)
Note: If the PWM duty cycle value is longer than
the PWM period, the CCP4 pin will not be
cleared.
FOSC
FPWM
---------------
log
2log
----------------------------- b i t s=
PWM Resolution (max)
PWM Frequency 2.44 kHz 9.77 kHz 39.06 kHz 156.25 kHz 312.50 kHz 416.67 kHz
Timer Prescaler (1, 4, 16)1641111
PR2 Value FFh FFh FFh 3Fh 1Fh 17h
Maximum Resolution (bits) 10 10 10 8 7 6.58
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NOTES:
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20.0 MASTER SYNCHRONOUS
SERIAL PORT (MSSP)
MODULE
20.1 Master SSP (MSSP) Module
Overview
The Master Synchronous Serial Port (MSSP) module is
a serial interface, useful for communicating with other
peripheral or microcontroller devices. These peripheral
devices may be serial EEPROMs, shift registers,
display drivers, A/D Converters, etc. The MSSP
module can operate in one of two modes:
• Serial Peripheral Interface (SPI)
• Inter-Integrated Circuit™ (I2C™)
- Full Master mode
- Slave mode (with general address call)
The I2C interface supports the following modes in
hardware:
•Master mode
• Multi-Master mode
• Slave mode with 5-bit and 7-bit address masking
(with address masking for both 10-bit and 7-bit
addressing)
All members of the PIC18F97J94 family have two
MSSP modules, designated as MSSP1 and MSSP2.
Each module operates independently of the other.
20.2 Control Registers
Each MSSP module has four associated control regis-
ters. These include a status register (SSPxSTAT) and
three control registers (SSPxCON1, SSPxCON2, and
SSPxCON3). The use of these registers and their indi-
vidual Configuration bits differ significantly depending
on whether the MSSP module is operated in SPI or I2C
mode.
Additional details are provided under the individual
sections. On all PIC18F97J94 family devices, the SPI
DMA capability can only be used in conjunction with
MSSP1. The SPI DMA feature is described in
Section 20.4 “SPI DMA Module”.
Note: Throughout this section, generic refer-
ences to an MSSP module in any of its
operating modes may be interpreted as
being equally applicable to MSSP1 or
MSSP2. Register names and module I/O
signals use the generic designator ‘x’ to
indicate the use of a numeral to distin-
guish a particular module when required.
Control bit names are not individuated.
Note: In devices with more than one MSSP
module, it is very important to pay close
attention to SSPxCON register names.
SSP1CON1 and SSP1CON2 control
different operational aspects of the same
module, while SSP1CON1 and SSP2CON1
control the same features for two different
modules.
Note: The SSPxBUF register cannot be used
with read-modify-write instructions, such
as BCF, COMF, etc.
To avoid lost data in Master mode, a
read of the SSPxBUF must be per-
formed to clear the Buffer Full (BF)
detect bit (SSPSTAT<0>) between each
transmission.
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DS30575A-page 352 2012 Microchip Technology Inc.
20.3 SPI Mode
The SPI mode allows 8 bits of data to be synchronously
transmitted and received simultaneously. All four
modes of SPI are supported. To accomplish communi-
cation, three pins are typically used. These pins must
be assigned through the PPS-Lite Configuration
registers before use.
• Serial Data Out (SDOx) – Mapped to pin using
PPS-Lite Peripheral Output registers
• Serial Data In (SDIx) – Mapped to pin using
PPS-Lite Peripheral Input registers
• Serial Clock (SCKx) – Mapped to pin using
PPS-Lite Peripheral Input registers (for Slave
mode) or Peripheral Output registers (for Master
mode).
Additionally, a fourth pin may be used when in a Slave
mode of operation:
• Slave Select (SSx) – Mapped through PPS-Lite
Peripheral Input registers
Figure 20-1 shows the block diagram of the MSSPx
module when operating in SPI mode.
FIGURE 20-1: MSSPx BLOCK DIAGRAM
(SPI MODE)
(
)
Read Write
Internal
Data Bus
SSPxSR reg
SSPM<3:0>
bit 0 Shift
Clock
SSx Control
Enable
Edge
Select
Clock Select
TMR2 Output
TOSC
Prescaler
4, 16, 64
2
Edge
Select
2
4
Data to TXx/RXx in SSPxSR
TRIS bit
2
SMP:CKE
SDOx
SSPxBUF reg
SDIx
SSx
SCKx
Note: PPS-Lite signal names are used in this dia-
gram for the sake of brevity. Refer to the text
for a full list of multiplexed functions.
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20.3.1 REGISTERS
Each MSSP module has four registers for SPI mode
operation. These are:
• MSSPx Control Register 1 (SSPxCON1)
• MSSPx Status Register (SSPxSTAT)
• MSSPx Control Register 3 (SSPxCON3)
• Serial Receive/Transmit Buffer Register
(SSPxBUF)
• MSSPx Shift Register (SSPxSR) – Not directly
accessible
SSPxCON1, SSPxCON3 and SSPxSTAT are the con-
trol and status registers in SPI mode operation. The
SSPxCON1 and SSPxCON3 registers are readable
and writable. The lower 6 bits of the SSPxSTAT are
read-only. The upper two bits of the SSPxSTAT are
read/write.
SSPxSR is the shift register used for shifting data in or
out. SSPxBUF is the buffer register to which data bytes
are written to or read from.
In receive operations, SSPxSR and SSPxBUF
together, create a double-buffered receiver. When
SSPxSR receives a complete byte, it is transferred to
SSPxBUF and the SSPxIF interrupt is set.
During transmission, the SSPxBUF is not double-
buffered. A write to SSPxBUF will write to both
SSPxBUF and SSPxSR.
REGISTER 20-1: SSPxSTAT: MSSPx STATUS REGISTER (SPI MODE)
R/W-0 R/W-0 R-0 R-0 R-0 R-0 R-0 R-0
SMP CKE(1)D/A PSR/WUA BF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 SMP: Sample bit
SPI Master mode:
1 = Input data is sampled at the end of data output time
0 = Input data is sampled at the middle of data output time
SPI Slave mode:
SMP must be cleared when SPI is used in Slave mode.
bit 6 CKE: SPI Clock Select bit(1)
1 = Transmit occurs on the transition from active to Idle clock state
0 = Transmit occurs on the transition from Idle to active clock state
bit 5 D/A: Data/Address bit
Used in I2C™ mode only.
bit 4 P: Stop bit
Used in I2C mode only. This bit is cleared when the MSSPx module is disabled; SSPEN is cleared.
bit 3 S: Start bit
Used in I2C mode only.
bit 2 R/W: Read/Write Information bit
Used in I2C mode only.
bit 1 UA: Update Address bit
Used in I2C mode only.
bit 0 BF: Buffer Full Status bit (Receive mode only)
1 = Receive is complete, SSPxBUF is full
0 = Receive is not complete, SSPxBUF is empty
Note 1: Polarity of clock state is set by the CKP bit (SSPxCON1<4>).
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REGISTER 20-2: SSPxCON1: MSSPx CONTROL REGISTER 1 (SPI MODE)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
WCOL SSPOV(1)SSPEN(2)CKP SSPM3(4)SSPM2(4)SSPM1(4)SSPM0(4)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 WCOL: Write Collision Detect bit
1 = The SSPxBUF register is written while it is still transmitting the previous word (must be cleared in
software)
0 = No collision
bit 6 SSPOV: Receive Overflow Indicator bit(1)
SPI Slave mode:
1 = A new byte is received while the SSPxBUF register is still holding the previous data. In case of
overflow, the data in SSPxSR is lost. Overflow can only occur in Slave mode. The user must read
the SSPxBUF, even if only transmitting data, to avoid setting overflow (must be cleared in
software).
0 = No overflow
bit 5 SSPEN: Master Synchronous Serial Port Enable bit(2)
1 = Enables serial port and configures SCKx, SDOx, SDIx and SSx as serial port pins
0 = Disables serial port and configures these pins as I/O port pins
bit 4 CKP: Clock Polarity Select bit
1 = Idle state for the clock is a high level
0 = Idle state for the clock is a low level
bit 3-0 SSPM<3:0>: Master Synchronous Serial Port Mode Select bits(4)
1010 = SPI Master mode: Clock = FOSC/(4 * (SSPxADD + 1)(3)
0101 = SPI Slave mode: Clock = SCKx pin; SSx pin control is disabled; SSx can be used as I/O pin
0100 = SPI Slave mode: Clock = SCKx pin; SSx pin control is enabled
0011 = SPI Master mode: Clock = TMR2 output/2
0010 = SPI Master mode: Clock = FOSC/64
0001 = SPI Master mode: Clock = FOSC/16
0000 = SPI Master mode: Clock = FOSC/4
Note 1: In Master mode, the overflow bit is not set since each new reception (and transmission) is initiated by
writing to the SSPxBUF register.
2: When enabled, these pins must be properly configured as inputs or outputs.
3: SSPxADD = 0 is not supported.
4: Bit combinations not specifically listed here are either reserved or implemented in I2C™ mode only.
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REGISTER 20-3: SSPxCON3: MSSP CONTROL REGISTER 3 (SPI MODE)
R/HS/HC-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ACKTIM: Acknowledge Time Status bit
Unused in SPI.
bit 6 PCIE: Stop Condition Interrupt Enable bit(1)
1 = Enable interrupt on detection of Stop condition
0 = Stop detection interrupts are disabled
bit 5 SCIE: Start Condition Interrupt Enable bit(1)
1 = Enable interrupt on detection of Start or Restart conditions
0 = Start detection interrupts are disabled
bit 4 BOEN: Buffer Overwrite Enable bit(2)
1 = SSPBUF updates every time a new data byte is shifted in, ignoring the BF bit
0 = If a new byte is received with BF bit already set, SSPOV is set, and the buffer is not updated
bit 3 SDAHT: SDA Hold Time Selection bit
Unused in SPI.
bit 2 SBCDE: Slave Mode Bus Collision Detect Enable bit
Unused in SPI.
bit 1 AHEN: Address Hold Enable bit
Unused in SPI.
bit 0 DHEN: Data Hold Enable bit
Unused in SPI.
Note 1: This bit has no effect in Slave modes that Start and Stop condition detection is explicitly listed as enabled.
2: For daisy-chained SPI operation; allows the user to ignore all but the last received byte. SSPOV is still set
when a new byte is received and BF = 1, but hardware continues to write the most recent byte to
SSPxBUF.
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20.3.2 OPERATION
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits (SSPxCON1<5:0> and SSPxSTAT<7:6>).
These control bits allow the following to be specified:
• I/O pins must be mapped to the SPI peripheral in
order to function. See Section 11.15 “PPS-Lite”
for an explanation of the PPS-Lite mapping
feature.
• Master mode (SCKx is the clock output)
• Slave mode (SCKx is the clock input)
• Clock Polarity (Idle state of SCKx)
• Data Input Sample Phase (middle or end of data
output time)
• Clock Edge (output data on rising/falling edge of
SCKx)
• Clock Rate (Master mode only)
• Slave Select mode (Slave mode only)
Each MSSPx module consists of a Transmit/Receive
Shift register (SSPxSR) and a Buffer register
(SSPxBUF). The SSPxSR shifts the data in and out of
the device, MSb first. The SSPxBUF holds the data that
was written to the SSPxSR until the received data is
ready. Once the 8 bits of data have been received, that
byte is moved to the SSPxBUF register. Then, the
Buffer Full detect bit, BF (SSPxSTAT<0>), and the
interrupt flag bit, SSPxIF, are set. This double-buffering
of the received data (SSPxBUF) allows the next byte to
start reception before reading the data that was just
received. Any write to the SSPxBUF register during
transmission/reception of data will be ignored and the
Write Collision Detect bit, WCOL (SSPxCON1<7>), will
be set. User software must clear the WCOL bit so that
it can be determined if the following write(s) to the
SSPxBUF register completed successfully.
When the application software is expecting to receive
valid data, the SSPxBUF should be read before the
next byte of data to transfer is written to the SSPxBUF.
The Buffer Full bit, BF (SSPxSTAT<0>), indicates when
SSPxBUF has been loaded with the received data
(transmission is complete). When the SSPxBUF is
read, the BF bit is cleared. This data may be irrelevant
if the SPI is only a transmitter. Generally, the MSSPx
interrupt is used to determine when the transmission/
reception has completed. If the interrupt method is not
going to be used, then software polling can be done to
ensure that a write collision does not occur.
Example 20-1 shows the loading of the SSPxBUF
(SSPxSR) for data transmission.
The SSPxSR is not directly readable or writable and
can only be accessed by addressing the SSPxBUF
register. Additionally, the SSPxSTAT register indicates
the various status conditions.
20.3.3 OPEN-DRAIN OUTPUT OPTION
The drivers for the SDOx output and SCKx clock pins
can be optionally configured as open-drain outputs.
This feature allows the voltage level on the pin to be
pulled to a higher level through an external pull-up
resistor, and allows the output to communicate with
external circuits without the need for additional level
shifters. For more information, see Section 11.1.3
“Open-Drain Outputs”.
The open-drain output option is controlled by the
SSPxOD bits (ODCON1<1:0>). Setting an SSPxOD bit
configures the SDOx and SCKx pins for the
corresponding module for open-drain operation.
EXAMPLE 20-1: LOADING THE SSP1BUF (SSP1SR) REGISTER
Note: To avoid lost data in Master mode, a
read of the SSPxBUF must be per-
formed to clear the Buffer Full (BF)
detect bit (SSPxSTAT<0>) between
each transmission.
LOOP BTFSS SSP1STAT, BF ;Has data been received (transmit complete)?
BRA LOOP ;No
MOVF SSP1BUF, W ;WREG reg = contents of SSP1BUF
MOVWF RXDATA ;Save in user RAM, if data is meaningful
MOVF TXDATA, W ;W reg = contents of TXDATA
MOVWF SSP1BUF ;New data to xmit
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20.3.4 ENABLING SPI I/O
To enable the serial port, the peripheral must first be
mapped to I/O pins using the PPS-Lite feature. To
enable the SPI peripheral, the MSSPx Enable bit,
SSPEN (SSPxCON1<5>) must be set. To reset or
reconfigure SPI mode, clear the SSPEN bit, re-initialize
the SSPxCON registers and then set the SSPEN bit.
This configures the SDIx, SDOx, SCKx and SSx pins
as serial port pins. For the pins to behave as the serial
port function, some must have their data direction bits
(in the TRIS register) appropriately programmed as
follows:
• SDIx is automatically controlled by the SPI
module
• SDOx must have the TRIS bit cleared for the
corresponding RPn pin.
• SCKx (Master mode) must have the TRIS bit
cleared for the corresponding RPn pin
• SCKx (Slave mode) must have the TRIS bit set
for the corresponding RPn pin
• SSx must have the TRIS bit set for the
corresponding RPn pin.
Any serial port function that is not desired may be
overridden by programming the corresponding Data
Direction (TRIS) register to the opposite value.
20.3.5 TYPICAL CONNECTION
Figure 20-2 shows a typical connection between two
microcontrollers. The master controller (Processor 1)
initiates the data transfer by sending the SCKx signal.
Data is shifted out of both shift registers on their pro-
grammed clock edge and latched on the opposite edge
of the clock. Both processors should be programmed to
the same Clock Polarity (CKP), then both controllers
would send and receive data at the same time.
Whether the data is meaningful (or dummy data)
depends on the application software. This leads to
three scenarios for data transmission:
• Master sends data–Slave sends dummy data
• Master sends data–Slave sends data
• Master sends dummy data–Slave sends data
FIGURE 20-2: SPI MASTER/SLAVE CONNECTION
Serial Input Buffer
(SSPxBUF)
Shift Register
(SSPxSR)
MSb LSb
SDOx
SDIx
PROCESSOR 1
SCKx
SPI Master SSPM<3:0> = 00xxb
Serial Input Buffer
(SSPxBUF)
Shift Register
(SSPxSR)
LSb
MSb
SDIx
SDOx
PROCESSOR 2
SCKx
SPI Slave SSPM<3:0> = 010xb
Serial Clock
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20.3.6 MASTER MODE
The master can initiate the data transfer at any time
because it controls the SCKx signal. The master deter-
mines when the slave (Processor 2, Figure 20-2) is to
broadcast data by the software protocol.
In Master mode, the data is transmitted/received as
soon as the SSPxBUF register is written to. If the SPI
is only going to receive, the SDOx output could be dis-
abled (programmed as an input). The SSPxSR register
will continue to shift in the signal present on the SDIx
pin at the programmed clock rate. As each byte is
received, it will be loaded into the SSPxBUF register as
if a normal received byte (interrupts and status bits
appropriately set). This could be useful in receiver
applications as a “Line Activity Monitor” mode.
The clock polarity is selected by appropriately program-
ming the CKP bit (SSPxCON1<4>). This, then, would
give waveforms for SPI communication, as shown in
Figure 20-3, Figure 20-5 and Figure 20-6, where the
MSB is transmitted first. In Master mode, the SPI clock
rate (bit rate) is user-programmable to be one of the
following:
•F
OSC/4 (or TCY)
•F
OSC/(4 * (SSPxADD + 1)
•FOSC/16 (or 4 • TCY)
•FOSC/64 (or 16 • TCY)
• Timer2 output/2
This allows a maximum data rate (at 64 MHz) of
16.00 Mbps.
Figure 20-3 shows the waveforms for Master mode.
When the CKE bit is set, the SDOx data is valid before
there is a clock edge on SCKx. The change of the input
sample is shown based on the state of the SMP bit. The
time when the SSPxBUF is loaded with the received
data is shown.
FIGURE 20-3: SPI MODE WAVEFORM (MASTER MODE)
SCKx
(CKP = 0
SCKx
(CKP = 1
SCKx
(CKP = 0
SCKx
(CKP = 1
4 Clock
Modes
Input
Sample
Input
Sample
SDIx
bit 7 bit 0
SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
bit 7
SDIx
SSPxIF
(SMP = 1)
(SMP = 0)
(SMP = 1)
CKE = 1)
CKE = 0)
CKE = 1)
CKE = 0)
(SMP = 0)
Write to
SSPxBUF
SSPxSR to
SSPxBUF
SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
(CKE = 0)
(CKE = 1)
Next Q4 Cycle
after Q2
bit 0
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20.3.7 SLAVE MODE
In Slave mode, the data is transmitted and received as
the external clock pulses appear on SCKx. When the
last bit is latched, the SSPxIF interrupt flag bit is set.
While in Slave mode, the external clock is supplied by
the external clock source on the SCKx pin. This
external clock must meet the minimum high and low
times as specified in the electrical specifications.
While in Sleep mode, the slave can transmit/receive
data. When a byte is received, the device can be
configured to wake-up from Sleep.
20.3.8 SLAVE SELECT
SYNCHRONIZATION
The SSx pin allows a Synchronous Slave mode. The
SPI must be in Slave mode with the SSx pin control
enabled (SSPxCON1<3:0> = 04h). When the SSx pin
is low, transmission and reception are enabled and the
SDOx pin is driven. When the SSx pin goes high, the
SDOx pin is no longer driven, even if in the middle of a
transmitted byte and becomes a floating output.
External pull-up/pull-down resistors may be desirable
depending on the application.
When the SPI module resets, the bit counter is forced
to ‘0’. This can be done by either forcing the SSx pin to
a high level or clearing the SSPEN bit.
To emulate two-wire communication, the SDOx pin can
be connected to the SDIx pin. When the SPI needs to
operate as a receiver, the SDOx pin can be configured
as an input. This disables transmissions from the
SDOx. The SDIx can always be left as an input (SDIx
function) since it cannot create a bus conflict.
FIGURE 20-4: SLAVE SYNCHRONIZATION WAVEFORM
Note: When the SPI is in Slave mode with
SSx pin control enabled
(SSPxCON1<3:0> = 0100), the SPI
module will reset if the SSx pin is set to
VDD.
If the SPI is used in Slave mode with CKE
set, then the SSx pin control must be
enabled.
SCKx
(CKP = 1
SCKx
(CKP = 0
Input
Sample
SDIx
bit 7
SDOx bit 7 bit 6 bit 7
SSPxIF
Interrupt
(SMP = 0)
CKE = 0)
CKE = 0)
(SMP = 0)
Write to
SSPxBUF
SSPxSR to
SSPxBUF
SSx
Flag
bit 0
bit 7
bit 0
Next Q4 Cycle
after Q2
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FIGURE 20-5: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 0)
FIGURE 20-6: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 1)
SCKx
(CKP = 1
SCKx
(CKP = 0
Input
Sample
SDIx
bit 7
SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
SSPxIF
Interrupt
(SMP = 0)
CKE = 0)
CKE = 0)
(SMP = 0)
Write to
SSPxBUF
SSPxSR to
SSPxBUF
SSx
Flag
Optional
Next Q4 Cycle
after Q2
bit 0
SCKx
(CKP = 1
SCKx
(CKP = 0
Input
Sample
SDIx
bit 7 bit 0
SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
SSPxIF
Interrupt
(SMP = 0)
CKE = 1)
CKE = 1)
(SMP = 0)
Write to
SSPxBUF
SSPxSR to
SSPxBUF
SSx
Flag
Not Optional
Next Q4 Cycle
after Q2
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20.3.9 OPERATION IN POWER-MANAGED
MODES
In SPI Master mode, module clocks may be operating
at a different speed than when in full-power mode. In
the case of Sleep mode, all clocks are halted.
In Idle modes, a clock is provided to the peripherals.
That clock can be from the primary clock source, the
secondary clock (SOSC Oscillator) or the INTOSC
source.
In most cases, the speed that the master clocks SPI
data is not important; however, this should be
evaluated for each system.
If MSSPx interrupts are enabled, they can wake the
controller from Sleep mode, or one of the Idle modes,
when the master completes sending data. If an exit
from Sleep or Idle mode is not desired, MSSPx
interrupts should be disabled.
If the Sleep mode is selected, all module clocks are
halted and the transmission/reception will remain in
that state until the device wakes. After the device
returns to Run mode, the module will resume
transmitting and receiving data.
In SPI Slave mode, the SPI Transmit/Receive Shift
register operates asynchronously to the device. This
allows the device to be placed in any power-managed
mode and data to be shifted into the SPI Transmit/
Receive Shift register. When all 8 bits have been
received, the MSSPx interrupt flag bit will be set, and if
enabled, will wake the device.
20.3.10 EFFECTS OF A RESET
A Reset disables the MSSPx module and terminates
the current transfer.
20.3.11 BUS MODE COMPATIBILITY
Table 20-1 shows the compatibility between the
standard SPI modes and the states of the CKP and
CKE control bits.
TABLE 20-1: SPI BUS MODES
There is also an SMP bit which controls when the data
is sampled.
20.3.12 SPI CLOCK SPEED AND MODULE
INTERACTIONS
Because MSSP1 and MSSP2 are independent
modules, they can operate simultaneously at different
data rates. Setting the SSPM<3:0> bits of the
SSPxCON1 register determines the rate for the
corresponding module.
An exception is when both modules use Timer2 as a
time base in Master mode. In this instance, any
changes to the Timer2 module’s operation will affect
both MSSPx modules equally. If different bit rates are
required for each module, the user should select one of
the other three time base options for one of the
modules.
Standard SPI Mode
Terminology
Control Bits State
CKP CKE
0, 001
0, 100
1, 011
1, 110
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20.4 SPI DMA MODULE
The SPI DMA module contains control logic to allow the
MSSP1 module to perform SPI Direct Memory Access
transfers. This enables the module to quickly transmit
or receive large amounts of data with relatively little
CPU intervention. When the SPI DMA module is used,
MSSP1 can directly read and write to general purpose
SRAM. When the SPI DMA module is not enabled,
MSSP1 functions normally, but without DMA capability.
The SPI DMA module is composed of control logic, a
Destination Receive Address Pointer, a Transmit Source
Address Pointer, an interrupt manager and a Byte Count
register for setting the size of each DMA transfer. The
DMA module may be used with all SPI Master and Slave
modes, and supports both half-duplex and full-duplex
transfers.
20.4.1 I/O PIN CONSIDERATIONS
When enabled, the SPI DMA module uses the MSSP1
module. All SPI input and output signals, related to
MSSP1, are routed through the Peripheral Pin Select
(PPS) module. The appropriate initialization procedure,
as described in Section 20.4.6 “Using the SPI DMA
Module”, will need to be followed prior to using the SPI
DMA module. The output pins assigned to the SDO
and SCK functions can optionally be configured as
open-drain outputs, such as for level shifting operations
mentioned in the same section.
20.4.2 RAM TO RAM COPY OPERATIONS
Although the SPI DMA module is primarily intended to
be used for SPI communication purposes, the module
can also be used to perform RAM to RAM copy opera-
tions. To do this, configure the module for Full-Duplex
Master mode operation, but assign the SDO output and
SDI input functions onto the same RPn pin in the PPS-
Lite module. Also assign SCK out and SCK in onto the
same RPn pin (a different pin than used for SDO and
SDI). This will allow the module to operate in Loopback
mode, providing RAM copy capability.
20.4.3 IDLE AND SLEEP
CONSIDERATIONS
The SPI DMA module remains fully functional when the
microcontroller is in Idle mode.
During normal Sleep, the SPI DMA module is not func-
tional and should not be used. To avoid corrupting a
transfer, user firmware should be careful to make
certain that pending DMA operations are complete by
polling the DMAEN bit in the DMACON1 register, prior
to putting the microcontroller into Sleep.
In SPI Slave modes, the MSSP1 module is capable of
transmitting and/or receiving one byte of data while in
Sleep mode. This allows the SSP1IF flag in the PIR1
register to be used as a wake-up source. When the
DMAEN bit is cleared, the SPI DMA module is
effectively disabled, and the MSSP1 module functions
normally, but without DMA capabilities. If the DMAEN
bit is clear prior to entering Sleep, it is still possible to
use the SSP1IF as a wake-up source without any data
loss.
Neither MSSP1 nor the SPI DMA module will provide
any functionality in Deep Sleep. Upon exiting from
Deep Sleep, all of the I/O pins, MSSP1 and SPI DMA
related registers will need to be fully re-initialized
before the SPI DMA module can be used again.
20.4.4 REGISTERS
The SPI DMA engine is enabled and controlled by the
following Special Function Registers:
• DMACON1 • DMACON2
• TXADDRH • TXADDRL
• RXADDRH • RXADDRL
• DMABCH • DMABCL
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20.4.4.1 DMACON1
The DMACON1 register is used to select the main
operating mode of the SPI DMA module. The SSCON1
and SSCON0 bits are used to control the slave select
pin.
When MSSP1 is used in SPI Master mode with the SPI
DMA module, SSDMA can be controlled by the DMA
module as an output pin. If MSSP1 will be used to com-
municate with an SPI slave device that needs the SSx
pin to be toggled periodically, the SPI DMA hardware
can automatically be used to de-assert SSx between
each byte, every two bytes or every four bytes.
Alternatively, user firmware can manually generate
slave select signals with normal general purpose I/O
pins, if required by the slave device(s).
When the TXINC bit is set, the TXADDR register will
automatically increment after each transmitted byte.
Automatic transmit address increment can be disabled
by clearing the TXINC bit. If the automatic transmit
address increment is disabled, each byte which is out-
put on SDO will be the same (the contents of the SRAM
pointed to by the TXADDR register) for the entire DMA
transaction.
When the RXINC bit is set, the RXADDR register will
automatically increment after each received byte.
Automatic receive address increment can be disabled
by clearing the RXINC bit. If RXINC is disabled in Full-
Duplex or Half-Duplex Receive modes, all incoming
data bytes on SDI will overwrite the same memory
location pointed to by the RXADDR register. After the
SPI DMA transaction has completed, the last received
byte will reside in the memory location pointed to by the
RXADDR register.
The SPI DMA module can be used for either half-duplex
receive only communication, half-duplex transmit only
communication or full-duplex simultaneous transmit and
receive operations. All modes are available for both SPI
master and SPI slave configurations. The DUPLEX0
and DUPLEX1 bits can be used to select the desired
operating mode.
The behavior of the DLYINTEN bit varies greatly
depending on the SPI operating mode. For example
behavior for each of the modes, see Figure 20-3
through Figure 20-6.
SPI Slave mode, DLYINTEN = 1: In this mode, an
SSP1IF interrupt will be generated during a transfer if
the time between successful byte transmission events
is longer than the value set by the DLYCYC<3:0> bits
in the DMACON2 register. This interrupt allows slave
firmware to know that the master device is taking an
unusually large amount of time between byte transmis-
sions. For example, this information may be useful for
implementing application defined communication
protocols, involving time-outs if the bus remains Idle for
too long. When DLYINTEN = 1, the DLYLVL<3:0>
interrupts occur normally according to the selected
setting.
SPI Slave mode, DLYINTEN = 0: In this mode, the
time-out based interrupt is disabled. No additional
SSP1IF interrupt events will be generated by the SPI
DMA module, other than those indicated by the
INTLVL<3:0> bits in the DMACON2 register. In this
mode, always set DLYCYC<3:0> = 0000.
SPI Master mode, DLYINTEN = 0: The DLYCYC<3:0>
bits in the DMACON2 register determine the amount of
additional inter-byte delay, which is added by the SPI
DMA module during a transfer; the Master mode SS1
output feature may be used.
SPI Master mode, DLYINTEN = 1: The amount of
hardware overhead is slightly reduced in this mode,
and the minimum inter-byte delay is 8 T
CY for FOSC/4,
9 TCY for FOSC/16 and 15 TCY for FOSC/64. This mode
can potentially be used to obtain slightly higher effec-
tive SPI bandwidth. In this mode, the SS1 control
feature cannot be used and should always be disabled
(DMACON1<7:6> = 00). Additionally, the interrupt
generating hardware (used in Slave mode) remains
active. To avoid extraneous SSP1IF interrupt events,
set the DMACON2 Delay bits, DLYCYC<3:0> = 1111,
and ensure that the SPI serial clock rate is no slower
than FOSC/64.
In SPI Master modes, the DMAEN bit is used to enable
the SPI DMA module and to initiate an SPI DMA trans-
action. After user firmware sets the DMAEN bit, the
DMA hardware will begin transmitting and/or receiving
data bytes according to the configuration used. In SPI
Slave modes, setting the DMAEN bit will finish the
initialization steps needed to prepare the SPI DMA
module for communication (which must still be initiated
by the master device).
To avoid possible data corruption, once the DMAEN bit
is set, user firmware should not attempt to modify any
of the MSSP2 or SPI DMA related registers, with the
exception of the INTLVLx bits in the DMACON2
register.
If user firmware wants to halt an ongoing DMA transac-
tion, the DMAEN bit can be manually cleared by the
firmware. Clearing the DMAEN bit while a byte is
currently being transmitted will not immediately halt the
byte in progress. Instead, any byte currently in
progress will be completed before the MSSP1 and SPI
DMA modules go back to their Idle conditions. If user
firmware clears the DMAEN bit, the TXADDR,
RXADDR and DMABC registers will no longer update,
and the DMA module will no longer make any
additional read or writes to SRAM; therefore, state
information can be lost.
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REGISTER 20-4: DMACON1: DMA CONTROL REGISTER 1
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
SSCON1 SSCON0 TXINC RXINC DUPLEX1 DUPLEX0 DLYINTEN DMAEN
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 SSCON<1:0>: SSDMA Output Control bits (Master modes only)
11 = SSDMA is asserted for the duration of 4 bytes; DLYINTEN is always reset low
01 = SSDMA is asserted for the duration of 2 bytes; DLYINTEN is always reset low
10 = SSDMA is asserted for the duration of 1 byte; DLYINTEN is always reset low
00 = SSDMA is not controlled by the DMA module; DLYINTEN bit is software programmable
bit 5 TXINC: Transmit Address Increment Enable bit
Allows the transmit address to increment as the transfer progresses.
1 = The transmit address is to be incremented from the initial value of TXADDR<11:0>
0 = The transmit address is always set to the initial value of TXADDR<11:0>
bit 4 RXINC: Receive Address Increment Enable bit
Allows the receive address to increment as the transfer progresses.
1 = The received address is to be incremented from the initial value of RXADDR<11:0>
0 = The received address is always set to the initial value of RXADDR<11:0>
bit 3-2 DUPLEX<1:0>: Transmit/Receive Operating Mode Select bits
10 = SPI DMA operates in Full-Duplex mode, data is simultaneously transmitted and received
01 = DMA operates in Half-Duplex mode, data is transmitted only
00 = DMA operates in Half-Duplex mode, data is received only
bit 1 DLYINTEN: Delay Interrupt Enable bit
Enables the interrupt to be invoked after the number of TCY cycles, specified in DLYCYC<3:0>, has
elapsed from the latest completed transfer.
1 = The interrupt is enabled, SSCON<1:0> must be set to ‘00’
0 = The interrupt is disabled
bit 0 DMAEN: DMA Operation Start/Stop bit
This bit is set by the users’ software to start the DMA operation. It is reset back to zero by the DMA
engine when the DMA operation is completed or aborted.
1 = DMA is in session
0 = DMA is not in session
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20.4.4.2 DMACON2
The DMACON2 register contains control bits for
controlling interrupt generation and inter-byte delay
behavior. The INTLVL<3:0> bits are used to select
when an SSP1IF interrupt should be generated. The
function of the DLYCYC<3:0> bits depends on the SPI
operating mode (Master/Slave), as well as the
DLYINTEN setting. In SPI Master mode, the
DLYCYC<3:0> bits can be used to control how much
time the module will Idle between bytes in a transfer. By
default, the hardware requires a minimum delay of
8T
CY for FOSC/4, 9 TCY for FOSC/16 and 15 TCY for
FOSC/64. An additional delay can be added with the
DLYCYCx bits. In SPI Slave modes, the DLYCYC<3:0>
bits may optionally be used to trigger an additional
time-out based interrupt.
REGISTER 20-5: DMACON2: DMA CONTROL REGISTER 2
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
DLYCYC3 DLYCYC2 DLYCYC1 DLYCYC0 INTLVL3 INTLVL2 INTLVL1 INTLVL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 DLYCYC<3:0>: Delay Cycle Selection bits
When DLYINTEN = 0, these bits specify the additional delay (above the base overhead of the hard-
ware), in number of TCY cycles, before the SSP2BUF register is written again for the next transfer.
When DLYINTEN = 1, these bits specify the delay in number of TCY cycles from the latest completed
transfer before an interrupt to the CPU is invoked. In this case, the additional delay before the
SSP2BUF register is written again is 1 TCY + (base overhead of hardware).
1111 = Delay time in number of instruction cycles is 2,048 cycles
1110 = Delay time in number of instruction cycles is 1,024 cycles
1101 = Delay time in number of instruction cycles is 896 cycles
1100 = Delay time in number of instruction cycles is 768 cycles
1011 = Delay time in number of instruction cycles is 640 cycles
1010 = Delay time in number of instruction cycles is 512 cycles
1001 = Delay time in number of instruction cycles is 384 cycles
1000 = Delay time in number of instruction cycles is 256 cycles
0111 = Delay time in number of instruction cycles is 128 cycles
0110 = Delay time in number of instruction cycles is 64 cycles
0101 = Delay time in number of instruction cycles is 32 cycles
0100 = Delay time in number of instruction cycles is 16 cycles
0011 = Delay time in number of instruction cycles is 8 cycles
0010 = Delay time in number of instruction cycles is 4 cycles
0001 = Delay time in number of instruction cycles is 2 cycles
0000 = Delay time in number of instruction cycles is 1 cycle
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bit 3-0 INTLVL<3:0>: Watermark Interrupt Enable bits
These bits specify the amount of remaining data yet to be transferred (transmitted and/or received)
upon which an interrupt is generated.
1111 = Amount of remaining data to be transferred is 576 bytes
1110 = Amount of remaining data to be transferred is 512 bytes
1101 = Amount of remaining data to be transferred is 448 bytes
1100 = Amount of remaining data to be transferred is 384 bytes
1011 = Amount of remaining data to be transferred is 320 bytes
1010 = Amount of remaining data to be transferred is 256 bytes
1001 = Amount of remaining data to be transferred is 192 bytes
1000 = Amount of remaining data to be transferred is 128 bytes
0111 = Amount of remaining data to be transferred is 67 bytes
0110 = Amount of remaining data to be transferred is 32 bytes
0101 = Amount of remaining data to be transferred is 16 bytes
0100 = Amount of remaining data to be transferred is 8 bytes
0011 = Amount of remaining data to be transferred is 4 bytes
0010 = Amount of remaining data to be transferred is 2 bytes
0001 = Amount of remaining data to be transferred is 1 byte
0000 = Transfer complete
REGISTER 20-5: DMACON2: DMA CONTROL REGISTER 2 (CONTINUED)
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20.4.4.3 DMABCH and DMABCL
The DMABCH and DMABCL register pair forms a
10-bit Byte Count register, which is used by the SPI
DMA module to send/receive up to 1,024 bytes for each
DMA transaction. When the DMA module is actively
running (DMAEN = 1), the DMA Byte Count register dec-
rements after each byte is transmitted/received. The
DMA transaction will halt and the DMAEN bit will be
automatically cleared by hardware after the last byte has
completed. After a DMA transaction is complete, the
DMABC register will read 0x000.
Prior to initiating a DMA transaction by setting the
DMAEN bit, user firmware should load the appropriate
value into the DMABCH/DMABCL registers. The
DMABC is a “base zero” counter, so the actual number
of bytes which will be transmitted follows in
Equation 20-1.
For example, if user firmware wants to transmit 7 bytes
in one transaction, DMABC should be loaded with
006h. Similarly, if user firmware wishes to transmit
1,024 bytes, DMABC should be loaded with 3FFh.
EQUATION 20-1: BYTES TRANSMITTED
FOR A GIVEN DMABC
20.4.4.4 TXADDRH and TXADDRL
The TXADDRH and TXADDRL registers pair together
to form a 12-bit Transmit Source Address Pointer
register. In modes that use TXADDR (Full-Duplex and
Half-Duplex Transmit), the TXADDR will be incre-
mented after each byte is transmitted. Transmitted data
bytes will be taken from the memory location pointed to
by the TXADDR register. The contents of the memory
locations pointed to by TXADDR will not be modified by
the DMA module during a transmission.
The SPI DMA module can read from, and transmit data
from, all general purpose memory on the device, includ-
ing memory used for USB endpoint buffers. The SPI
DMA module cannot be used to read from the Special
Function Registers (SFRs) contained in Banks 14
and 15.
20.4.4.5 RXADDRH and RXADDRL
The RXADDRH and RXADDRL registers pair together
to form a 12-bit Receive Destination Address Pointer.
In modes that use RXADDR (Full-Duplex and Half-
Duplex Receive), the RXADDR register will be
incremented after each byte is received. Received data
bytes will be stored at the memory location pointed to
by the RXADDR register.
BytesXMIT DMABC 1+
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The SPI DMA module can write received data to all
general purpose memory on the device, including
memory used for USB endpoint buffers. The SPI DMA
module cannot be used to modify the Special Function
Registers contained in Banks 14 and 15.
20.4.5 INTERRUPTS
The SPI DMA module alters the behavior of the
SSP1IF interrupt flag. In normal non-DMA modes, the
SSP1IF is set once after every single byte is transmit-
ted/received through the MSSP1 module. When
MSSP1 is used with the SPI DMA module, the SSP1IF
interrupt flag will be set according to the user-selected
INTLVL<3:0> value specified in the DMACON2
register. The SSP1IF interrupt condition will also be
generated once the SPI DMA transaction has fully
completed and the DMAEN bit has been cleared by
hardware.
The SSP1IF flag becomes set once the DMA byte count
value indicates that the specified INTLVLx has been
reached. For example, if DMACON2<3:0> = 0101
(16 bytes remaining), the SSP1IF interrupt flag will
become set once DMABC reaches 00Fh. If user
firmware then clears the SSP1IF interrupt flag, the flag
will not be set again by the hardware until after all bytes
have been fully transmitted and the DMA transaction is
complete.
For example, if DMABC = 00Fh (implying 16 bytes are
remaining) and user firmware writes ‘1111’ to
INTLVL<3:0> (interrupt when 576 bytes are remaining),
the SSP1IF interrupt flag will immediately become set.
If user firmware clears this interrupt flag, a new inter-
rupt condition will not be generated until either: user
firmware again writes INTLVLx with an interrupt level
higher than the actual remaining level, or the DMA
transaction completes and the DMAEN bit is cleared.
Note: User firmware may modify the INTLVLx
bits while a DMA transaction is in progress
(DMAEN = 1). If an INTLVLx value is
selected which is higher than the actual
remaining number of bytes (indicated by
DMABC + 1), the SSP1IF interrupt flag
will immediately become set.
Note: If the INTLVLx bits are modified while a
DMA transaction is in progress, care
should be taken to avoid inadvertently
changing the DLYCYC<3:0> value.
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20.4.6 USING THE SPI DMA MODULE
The following steps would typically be taken to enable
and use the SPI DMA module:
1. Configure the I/O pins, which will be used by
MSSP2:
a) Assign SCK1, SDO1, SDI1 and SS1 to the
RPn pins, as appropriate for the SPI mode
which will be used. Only functions which will
be used need to be assigned to a pin.
b) Initialize the associated LATx registers for
the desired Idle SPI bus state.
c) If Open-Drain Output mode on SDO1 and
SCK1 (Master mode) is desired, set
ODCON1<1>.
d) Configure the corresponding TRISx bits for
each I/O pin used.
2. Configure and enable MSSP1 for the desired
SPI operating mode:
a) Select the desired operating mode (Master
or Slave, SPI Mode 0, 1, 2 and 3) and con-
figure the module by writing to the
SSP1STAT and SSP1CON1 registers.
b) Enable MSSP1 by setting
SSP1CON1<5> = 1.
3. Configure the SPI DMA engine:
a) Select the desired operating mode by
writing the appropriate values to
DMACON2 and DMACON1.
b) Initialize the TXADDRH/TXADDRL Pointer
(Full-Duplex or Half-Duplex Transmit Only
mode).
c) Initialize the RXADDRH/RXADDRL Pointer
(Full-Duplex or Half-Duplex Receive Only
mode).
d) Initialize the DMABCH/DMABCL Byte
Count register with the number of bytes to
be transferred in the next SPI DMA
operation.
e) Set the DMAEN bit (DMACON1<0>).
In SPI Master modes, this will initiate a DMA
transaction. In SPI Slave modes, this will com-
plete the initialization process, and the module
will now be ready to begin receiving and/or
transmitting data to the master device once the
master starts the transaction.
4. Detect the SSP1IF interrupt condition (PIR1<3):
a) If the interrupt was configured to occur at
the completion of the SPI DMA transaction,
the DMAEN bit (DMACON1<0>) will be
clear. User firmware may prepare the
module for another transaction by repeating
Steps 3.b through 3.e.
b) If the interrupt was configured to occur prior
to the completion of the SPI DMA trans-
action, the DMAEN bit may still be set,
indicating the transaction is still in progress.
User firmware would typically use this inter-
rupt condition to begin preparing new data
for the next DMA transaction. Firmware
should not repeat Steps 3.b. through 3.e.
until the DMAEN bit is cleared by the
hardware, indicating the transaction is
complete.
Example 20-3 provides example code, demonstrating
the initialization process and the steps needed to use
the SPI DMA module to perform a 512-byte Full-Duplex
Master mode transfer.
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EXAMPLE 20-2: 512-BYTE SPI MASTER MODE INIT AND TRANSFER
;For this example, let's use RP3(RA3) for SCK1,
;RP1(RA1) for SDO1, and RP0(RA0) for SDI1
;Let’s use SPI master mode, CKE = 0, CKP = 0,
;without using slave select signalling.
InitSPIPins:
movlb 0x0E ;Select bank 14, for access to ODCON1 register
bcf ODCON1, SSP1_OD ;Let’s not use open drain outputs in this example
bcf LATA, RA3 ;Initialize our (to be) SCK1 pin low (idle).
bcf LATA, RA1 ;Initialize our (to be) SDO1 pin to an idle state
bcf TRISA, RA1 ;Make SDO1 output, and drive low
bcf TRISA, RA3 ;Make SCK1 output, and drive low (idle state)
bsf TRISA, RA0 ;SDI2 is an input, make sure it is tri-stated
;Now we should unlock the PPS-Lite registers, so we can
;assign the MSSP2 functions to our desired I/O pins.
movlb 0x0F ;Select bank 15 for access to PPS-Lite registers
bcf INTCON, GIE ;I/O Pin unlock sequence will not work if CPU
;services an interrupt during the sequence
movlw 0x55 ;Unlock sequence consists of writing 0x55
movwf EECON2 ;and 0xAA to the EECON2 register.
movlw 0xAA
movwf EECON2
bcf OSCCON2, IOLOCK ;We may now write to RPINRx and RPORx registers
bsf INTCON, GIE ;May now turn back on interrupts if desired
movlw 0x00 ;RP0 will be SDI1
movwf RPINR8-9 ;Assign the SDI1 function to pin RP0
movlw 0x30 ;Let’s assign SCK1 output to pin RP3
movwf RPOR2_3 ;RPOR2_3 maps output signals to RP3 pin
movlw 0x00 ;
SCK1 also needs to be configured as an input on the same pin
movwf RPINR8_9 ;SCK1 input function taken from RP3 pin
movlw 0x40 ;0x40 is SDO1 output
movwf RPOR0_1 ;Assign SDO1 output signal to the RP1 (RA1) pin
movlb 0x0F ;Done with PPS-Lite registers, bank 15 has other SFRs
InitMSSP2:
clrf SSP1STAT ;CKE = 0, SMP = 0 (sampled at middle of bit)
movlw b'00000000' ;CKP = 0, SPI Master mode, Fosc/4
movwf SSP1CON1 ;MSSP2 initialized
bsf SSP1CON1, SSPEN ;Enable the MSSP2 module
InitSPIDMA:
movlw b'00111010' ;Full duplex, RX/TXINC enabled, no SSCON
movwf DMACON1 ;DLYINTEN is set, so DLYCYC3:DLYCYC0 = 1111
movlw b'11110000' ;Minimum delay between bytes, interrupt
movwf DMACON2 ;only once when the transaction is complete
;Somewhere else in our project, lets assume we have
;allocated some RAM for use as SPI receive and
;transmit buffers.
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; udata 0x500
;DestBuf res 0x200 ;Let’s reserve 0x500-0x6FF for use as our SPI
; ;receive data buffer in this example
;SrcBuf res 0x200 ;Lets reserve 0x700-0x8FF for use as our SPI
; ;transmit data buffer in this example
PrepareTransfer:
movlw HIGH(DestBuf) ;Get high byte of DestBuf address (0x05)
movwf RXADDRH ;Load upper four bits of the RXADDR register
movlw LOW(DestBuf) ;Get low byte of the DestBuf address (0x00)
movwf RXADDRL ;Load lower eight bits of the RXADDR register
movlw HIGH(SrcBuf) ;Get high byte of SrcBuf address (0x07)
movwf TXADDRH ;Load upper four bits of the TXADDR register
movlw LOW(SrcBuf) ;Get low byte of the SrcBuf address (0x00)
movwf TXADDRL ;Load lower eight bits of the TXADDR register
movlw 0x01 ;Lets move 0x200 (512) bytes in one DMA xfer
movwf DMABCH ;Load the upper two bits of DMABC register
movlw 0xFF ;Actual bytes transferred is (DMABC + 1), so
movwf DMABCL ;we load 0x01FF into DMABC to xfer 0x200 bytes
BeginXfer:
bsf DMACON1, DMAEN ;The SPI DMA module will now begin transferring
;the data taken from SrcBuf, and will store
;received bytes into DestBuf.
;Execute whatever ;CPU is now free to do whatever it wants to
;and the DMA operation will continue without
;intervention, until it completes.
;When the transfer is complete, the SSP2IF flag in
;the PIR3 register will become set, and the DMAEN bit
;is automatically cleared by the hardware.
;The DestBuf (0x500-0x7FF) will contain the received
;data. To start another transfer, firmware will need
;to reinitialize RXADDR, TXADDR, DMABC and then
;set the DMAEN bit.
EXAMPLE 20-2: 512-BYTE SPI MASTER MODE INIT AND TRANSFER (CONTINUED)
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20.5 I2C Mode
The MSSPx module in I2C™ mode fully implements all
master and slave functions (including general call
support), and provides interrupts on Start and Stop bits
in hardware to determine a free bus (multi-master
function). The MSSPx module implements the standard
mode specifications, as well as 7-bit and 10-bit
addressing.
Two pins are used for data transfer:
• Serial Clock (SCLx) – RC3/SCL1 or RD6/SCL2
• Serial Data (SDAx) – RC4/SDA1 or RD5/SDA2
The user must configure these pins as inputs by setting
the associated TRIS bits.
FIGURE 20-7: MSSPx BLOCK DIAGRAM
(I2C™ MODE)
20.5.1 REGISTERS
The MSSPx module has seven registers for I2C
operation. These are:
• MSSPx Control Register 1 (SSPxCON1)
• MSSPx Control Register 2 (SSPxCON2)
• MSSPx Control Register 3 (SSPxCON3)
• MSSPx Status Register (SSPxSTAT)
• Serial Receive/Transmit Buffer Register
(SSPxBUF)
• MSSPx Shift Register (SSPxSR) – Not directly
accessible
• MSSPx Address Register (SSPxADD)
•I
2C Slave Address Mask Register (SSPxMSK)
SSPxCON1, SSPxCON2, SSPxCON3 and SSPxSTAT
are the control and status registers in I2C mode opera-
tion. The SSPxCON1, SSPxCON2, and SSPxCON3
registers are readable and writable. The lower 6 bits of
the SSPxSTAT are read-only. The upper two bits of the
SSPxSTAT are read/write.
SSPxSR is the shift register used for shifting data in or
out. SSPxBUF is the buffer register to which data bytes
are written to or read from.
SSPxADD contains the slave device address when the
MSSPx is configured in I2C Slave mode. When the
MSSPx is configured in Master mode, the lower seven
bits of SSPxADD act as the Baud Rate Generator
reload value.
SSPxMSK holds the slave address mask value when
the module is configured for 7-Bit Address Masking
mode. While it is a separate register, it shares the same
SFR address as SSPxADD; it is only accessible when
the SSPM<3:0> bits are specifically set to permit
access. Additional details are provided in
Section 20.5.4.3 “7-Bit Address Masking Mode”.
In receive operations, SSPxSR and SSPxBUF
together, create a double-buffered receiver. When
SSPxSR receives a complete byte, it is transferred to
SSPxBUF and the SSPxIF interrupt is set.
During transmission, the SSPxBUF is not double-
buffered. A write to SSPxBUF will write to both
SSPxBUF and SSPxSR.
Read Write
Match Detect
SSPxADD reg
SSPxBUF reg
Internal
Data Bus
Addr Match
Set, Reset
S, P bits
(SSPxSTAT reg)
Shift
Clock
MSb LSb
Note: Only port I/O names are used in this diagram
for the sake of brevity. Refer to the text for a
full list of multiplexed functions.
SCKx
SDIx
Start and
Stop bit Detect
Address Mask
SSPxSR reg
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REGISTER 20-6: SSPxSTAT: MSSPx STATUS REGISTER (I2C™ MODE)
R/W-0 R/W-0 R-0 R-0 R-0 R-0 R-0 R-0
SMP CKE D/A P(1)S(1)R/W(2,3)UA BF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 SMP: Slew Rate Control bit
In Master or Slave mode:
1 = Slew rate control is disabled for Standard Speed mode (100 kHz and 1 MHz)
0 = Slew rate control is enabled for High-Speed mode (400 kHz)
bit 6 CKE: SMBus Select bit
In Master or Slave mode:
1 = Enables SMBus-specific inputs
0 = Disables SMBus-specific inputs
bit 5 D/A: Data/Address bit
In Master mode:
Reserved.
In Slave mode:
1 = Indicates that the last byte received or transmitted was data
0 = Indicates that the last byte received or transmitted was address
bit 4 P: Stop bit(1)
1 = Indicates that a Stop bit has been detected last
0 = Stop bit was not detected last
bit 3 S: Start bit(1)
1 = Indicates that a Start bit has been detected last
0 = Start bit was not detected last
bit 2 R/W: Read/Write Information bit(2,3)
In Slave mode:
1 = Read
0 = Write
In Master mode:
1 = Transmit is in progress
0 = Transmit is not in progress
bit 1 UA: Update Address bit (10-Bit Slave mode only)
1 = Indicates that the user needs to update the address in the SSPxADD register
0 = Address does not need to be updated
bit 0 BF: Buffer Full Status bit
In Transmit mode:
1 = SSPxBUF is full
0 = SSPxBUF is empty
In Receive mode:
1 = SSPxBUF is full (does not include the ACK and Stop bits)
0 = SSPxBUF is empty (does not include the ACK and Stop bits)
Note 1: This bit is cleared on Reset and when SSPEN is cleared.
2: This bit holds the R/W bit information following the last address match. This bit is only valid from the
address match to the next Start bit, Stop bit or not ACK bit.
3: ORing this bit with SEN, RSEN, PEN, RCEN or ACKEN will indicate if the MSSPx is in Active mode.
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REGISTER 20-7: SSPxCON1: MSSPx CONTROL REGISTER 1 (I2C™ MODE)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
WCOL SSPOV SSPEN(1)CKP SSPM3(2)SSPM2(2)SSPM1(2)SSPM0(2)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 WCOL: Write Collision Detect bit
In Master Transmit mode:
1 = A write to the SSPxBUF register was attempted while the I2C conditions were not valid for a
transmission to be started (must be cleared in software)
0 = No collision
In Slave Transmit mode:
1 = The SSPxBUF register is written while it is still transmitting the previous word (must be cleared in
software)
0 = No collision
In Receive mode (Master or Slave modes):
This is a “don’t care” bit.
bit 6 SSPOV: Receive Overflow Indicator bit
In Receive mode:
1 = A byte is received while the SSPxBUF register is still holding the previous byte (must be cleared in
software)
0 = No overflow
In Transmit mode:
This is a “don’t care” bit in Transmit mode.
bit 5 SSPEN: Master Synchronous Serial Port Enable bit(1)
1 = Enables the serial port and configures the SDAx and SCLx pins as the serial port pins
0 = Disables serial port and configures these pins as I/O port pins
bit 4 CKP: SCKx Release Control bit
In Slave mode:
1 = Releases clock
0 = Holds clock low (clock stretch), used to ensure data setup time
In Master mode:
Unused in this mode.
bit 3-0 SSPM<3:0>: Master Synchronous Serial Port Mode Select bits(2)
1111 = I2C Slave mode: 10-bit address with Start and Stop bit interrupts enabled
1110 = I2C Slave mode: 7-bit address with Start and Stop bit interrupts enabled
1011 = I2C Firmware Controlled Master mode (slave Idle)
1001 = Load SSPxMSK register at SSPxADD SFR address(3,4)
1000 = I2C Master mode: Clock = FOSC/(4 * (SSPxADD + 1))
0111 = I2C Slave mode: 10-bit address(3,4)
0110 = I2C Slave mode: 7-bit address
Note 1: When enabled, the SDAx and SCLx pins must be configured as inputs.
2: Bit combinations not specifically listed here are either reserved or implemented in SPI mode only.
3: When SSPM<3:0> = 1001, any reads or writes to the SSPxADD SFR address actually accesses the
SSPxMSK register.
4: This mode is only available when 7-Bit Address Masking mode is selected (MSSPMSK Configuration bit
is ‘1’).
2012 Microchip Technology Inc. DS30575A-page 375
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REGISTER 20-8: SSPxCON2: MSSPx CONTROL REGISTER 2 (I2C™ MASTER MODE)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
GCEN ACKSTAT ACKDT(1)ACKEN(2)RCEN(2)PEN(2)RSEN(2)SEN(2)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 GCEN: General Call Enable bit
Unused in Master mode.
bit 6 ACKSTAT: Acknowledge Status bit (Master Transmit mode only)
1 = Acknowledge was not received from slave
0 = Acknowledge was received from slave
bit 5 ACKDT: Acknowledge Data bit (Master Receive mode only)(1)
1 = Not Acknowledge
0 = Acknowledge
bit 4 ACKEN: Acknowledge Sequence Enable bit(2)
1 = Initiates Acknowledge sequence on SDAx and SCLx pins and transmits ACKDT data bit;
automatically cleared by hardware
0 = Acknowledge sequence is Idle
bit 3 RCEN: Receive Enable bit (Master Receive mode only)(2)
1 = Enables Receive mode for I2C™
0 = Receive is Idle
bit 2 PEN: Stop Condition Enable bit(2)
1 = Initiates Stop condition on SDAx and SCLx pins; automatically cleared by hardware
0 = Stop condition is Idle
bit 1 RSEN: Repeated Start Condition Enable bit(2)
1 = Initiates Repeated Start condition on SDAx and SCLx pins; automatically cleared by hardware
0 = Repeated Start condition is Idle
bit 0 SEN: Start Condition Enable bit(2)
1 = Initiates Start condition on SDAx and SCLx pins; automatically cleared by hardware
0 = Start condition is Idle
Note 1: The value that will be transmitted when the user initiates an Acknowledge sequence at the end of a
receive.
2: If the I2C module is active, these bits may not be set (no spooling) and the SSPxBUF may not be written
(or writes to the SSPxBUF are disabled).
PIC18F97J94 FAMILY
DS30575A-page 376 2012 Microchip Technology Inc.
REGISTER 20-9: SSPxCON3: MSSP CONTROL REGISTER 3 (I2C MASTER MODE)
R/HS/HC-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ACKTIM: Acknowledge Time Status bit
Unused in Master mode.
bit 6 PCIE: Stop Condition Interrupt Enable bit(1)
1 = Enable interrupt on detection of Stop condition
0 = Stop detection interrupts are disabled
bit 5 SCIE: Start Condition Interrupt Enable bit(1)
1 = Enable interrupt on detection of Start or Restart conditions
0 = Start detection interrupts are disabled
bit 4 BOEN: Buffer Overwrite Enable bit
1 = SSPBUF is updated every time a new data byte is available, ignoring the SSPOV effect on updating
the buffer
0 = SSPBUF is only updated when SSPOV is clear
bit 3 SDAHT: SDA Hold Time Selection bit
1 = Minimum of 300ns hold time on SDA after the falling edge of SCL
0 = Minimum of 100ns hold time on SDA after the falling edge of SCL
bit 2 SBCDE: Slave Mode Bus Collision Detect Enable bit
Unused in Master mode.
bit 1 AHEN: Address Hold Enable bit
Unused in Master mode.
bit 0 DHEN: Data Hold Enable bit
Unused in Master mode.
Note 1: This bit has no effect in Slave modes that Start and Stop condition detection is explicitly listed as enabled.
2012 Microchip Technology Inc. DS30575A-page 377
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REGISTER 20-10: SSPxCON2: MSSPx CONTROL REGISTER 2 (I2C™ SLAVE MODE)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
GCEN ACKSTAT ACKDT(1)ACKEN(1)RCEN(1)PEN(1)RSEN(1)SEN(1)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 GCEN: General Call Enable bit
1 = Enables interrupt when a general call address (0000h) is received in the SSPxSR
0 = General call address is disabled
bit 6 ACKSTAT: Acknowledge Status bit
Unused in Slave mode.
bit 5 ACKDT: Acknowledge Data bit (Master Receive mode only)(1)
1 = Not Acknowledge
0 = Acknowledge
bit 4 ACKEN: Acknowledge Sequence Enable bit(1)
1 = Initiates Acknowledge sequence on SDAx and SCLx pins and transmits ACKDT data bit;
automatically cleared by hardware
0 = Acknowledge sequence is Idle
bit 3 RCEN: Receive Enable bit (Master Receive mode only)(1)
1 = Enables Receive mode for I2C
0 = Receive is Idle
bit 2 PEN: Stop Condition Enable bit(1)
1 = Initiates Stop condition on SDAx and SCLx pins; automatically cleared by hardware
0 = Stop condition is Idle
bit 1 RSEN: Repeated Start Condition Enable bit(1)
1 = Initiates Repeated Start condition on SDAx and SCLx pins; automatically cleared by hardware
0 = Repeated Start condition is Idle
bit 0 SEN: Stretch Enable bit(1)
1 = Clock stretching is enabled for both slave transmit and slave receive (stretch enabled)
0 = Clock stretching is disabled
Note 1: If the I2C module is active, this bit may not be set (no spooling) and the SSPxBUF may not be written (or
writes to the SSPxBUF are disabled).
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DS30575A-page 378 2012 Microchip Technology Inc.
REGISTER 20-11: SSPxCON3: MSSP CONTROL REGISTER 3 (I2C SLAVE MODE)
R/HS/HC-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ACKTIM: Acknowledge Time Status bit
1 = Indicates the I2C bus is in an Acknowledge sequence, set on 8th falling edge of SCL clock
0 = Not an Acknowledge sequence, cleared on 9th rising edge of SCL clock
bit 6 PCIE: Stop Condition Interrupt Enable bit(1)
1 = Enable interrupt on detection of Stop condition
0 = Stop detection interrupts are disabled
bit 5 SCIE: Start Condition Interrupt Enable bit(1)
1 = Enable interrupt on detection of Start or Restart conditions
0 = Start detection interrupts are disabled
bit 4 BOEN: Buffer Overwrite Enable bit
1 = SSPBUF is updated every time a new data byte is available, ignoring the SSPOV effect on updating
the buffer
0 = SSPBUF is only updated when SSPOV is clear
bit 3 SDAHT: SDA Hold Time Selection bit
1 = Minimum of 300ns hold time on SDA after the falling edge of SCL
0 = Minimum of 100ns hold time on SDA after the falling edge of SCL
bit 2 SBCDE: Slave Mode Bus Collision Detect Enable bit
If, on the rising edge of SCL, SDA is sampled low when the module is outputting a high state, the BCLIF
bit is set, and bus goes Idle.
1 = Enable slave bus collision interrupts
0 = Slave bus collision interrupts are disabled
bit 1 AHEN: Address Hold Enable bit
1 = Following the 8th falling edge of SCL for a matching received address byte; CKP bit of SSPxCON1
will be cleared and the SCL will be held low.
0 = Address holding is disabled
bit 0 DHEN: Data Hold Enable bit
1 = Following the 8th falling edge of SCL for a received data byte; slave hardware clears the CKP bit
of SSPCON register and SCL is held low.
0 = Data holding is disabled
Note 1: This bit has no effect in Slave modes that Start and Stop condition detection is explicitly listed as enabled.
2012 Microchip Technology Inc. DS30575A-page 379
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REGISTER 20-12: SSPxMSK: MSSPx I2C™ SLAVE ADDRESS MASK REGISTER (7-BIT MASKING
MODE)(1)
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0(2)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 MSK<7:0>: Slave Address Mask Select bits
1 = Masking of corresponding bit of SSPxADD is enabled
0 = Masking of corresponding bit of SSPxADD is disabled
Note 1: This register shares the same SFR address as SSPxADD and is only addressable in select MSSPx
operating modes. See Section 20.5.4.3 “7-Bit Address Masking Mode” for more details.
2: MSK0 is not used as a mask bit in 7-bit addressing.
PIC18F97J94 FAMILY
DS30575A-page 380 2012 Microchip Technology Inc.
20.5.2 OPERATION
The MSSPx module functions are enabled by setting
the MSSPx Enable bit, SSPEN (SSPxCON1<5>).
The SSPxCON1 register allows control of the I2C oper-
ation. Four mode selection bits (SSPxCON1<3:0>)
allow one of the following I2C modes to be selected:
•I
2C Master mode, clock
•I
2C Slave mode (7-bit address)
•I
2C Slave mode (10-bit address)
•I
2C Slave mode (7-bit address) with Start and
Stop bit interrupts enabled
•I
2C Slave mode (10-bit address) with Start and
Stop bit interrupts enabled
•I
2C Firmware Controlled Master mode, slave is
Idle
Selection of any I2C mode, with the SSPEN bit set,
forces the SCLx and SDAx pins to be open-drain, pro-
vided these pins are programmed as inputs by setting
the appropriate TRISC or TRISD bits. To ensure proper
operation of the module, pull-up resistors must be
provided externally to the SCLx and SDAx pins.
20.5.3 SLAVE MODE
In Slave mode, the SCLx and SDAx pins must be
configured as inputs (TRISC<4:3> set). The MSSPx
module will override the input state with the output data
when required (slave-transmitter).
The I2C Slave mode hardware will always generate an
interrupt on an address match. Address masking will
allow the hardware to generate an interrupt for more
than one address (up to 31 in 7-bit addressing and up
to 63 in 10-bit addressing). Through the mode select
bits, the user can also choose to interrupt on Start and
Stop bits.
When an address is matched, or the data transfer after
an address match is received, the hardware auto-
matically will generate the Acknowledge (ACK) pulse
and load the SSPxBUF register with the received value
currently in the SSPxSR register.
Any combination of the following conditions will cause
the MSSPx module not to give this ACK pulse:
• The Buffer Full bit, BF (SSPxSTAT<0>), was set
before the transfer was received.
• The overflow bit, SSPOV (SSPxCON1<6>), was
set before the transfer was received.
In this case, the SSPxSR register value is not loaded
into the SSPxBUF, but bit, SSPxIF, is set. The BF bit is
cleared by reading the SSPxBUF register, while bit,
SSPOV, is cleared through software.
The SCLx clock input must have a minimum high and
low for proper operation. The high and low times of the
I2C specification, as well as the requirement of the
MSSPx module, are shown in timing Parameter 100
and Parameter 101.
20.5.4 ADDRESSING
Once the MSSPx module has been enabled, it waits for
a Start condition to occur. Following the Start condition,
the 8 bits are shifted into the SSPxSR register. All
incoming bits are sampled with the rising edge of the
clock (SCLx) line. The value of register, SSPxSR<7:1>,
is compared to the value of the SSPxADD register. The
address is compared on the falling edge of the eighth
clock (SCLx) pulse. If the addresses match, and the BF
and SSPOV bits are clear, the following events occur:
1. The SSPxSR register value is loaded into the
SSPxBUF register.
2. The Buffer Full bit, BF, is set.
3. An ACK pulse is generated.
4. The MSSPx Interrupt Flag bit, SSPxIF, is set
(and interrupt is generated if enabled) on the
falling edge of the ninth SCLx pulse.
In 10-Bit Addressing mode, two address bytes need to
be received by the slave. The five Most Significant bits
(MSbs) of the first address byte specify if this is a 10-bit
address. The R/W (SSPxSTAT<2>) bit must specify a
write so the slave device will receive the second
address byte. For a 10-bit address, the first byte would
equal ‘11110 A9 A8 0’, where ‘A9’ and ‘A8’ are the
two MSbs of the address. The sequence of events for
10-bit addressing is as follows, with Steps 7 through 9
for the slave-transmitter:
1. Receive first (high) byte of address (bits,
SSPxIF, BF and UA, are set on address match).
2. Update the SSPxADD register with second (low)
byte of address (clears bit, UA, and releases the
SCLx line).
3. Read the SSPxBUF register (clears bit, BF) and
clear flag bit, SSPxIF.
4. Receive second (low) byte of address (bits,
SSPxIF, BF and UA, are set).
5. Update the SSPxADD register with the first
(high) byte of address. If match releases SCLx
line, this will clear bit, UA.
6. Read the SSPxBUF register (clears bit, BF) and
clear flag bit SSPxIF.
7. Receive Repeated Start condition.
8. Receive first (high) byte of address (bits,
SSPxIF and BF, are set).
9. Read the SSPxBUF register (clears bit, BF) and
clear flag bit, SSPxIF.
2012 Microchip Technology Inc. DS30575A-page 381
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20.5.4.1 Address Masking Modes
Masking an address bit causes that bit to become a
“don’t care”. When one address bit is masked, two
addresses will be Acknowledged and cause an inter-
rupt. It is possible to mask more than one address bit at
a time, which greatly expands the number of addresses
Acknowledged.
The I2C slave behaves the same way, whether address
masking is used or not. However, when address mask-
ing is used, the I2C slave can Acknowledge multiple
addresses and cause interrupts. When this occurs, it is
necessary to determine which address caused the
interrupt by checking the SSPxBUF.
The PIC18F97J94 family of devices is capable of using
two different Address Masking modes in I2C slave
operation: 5-Bit Address Masking and 7-Bit Address
Masking. The Masking mode is selected at device con-
figuration using the MSSPMSK<2:1> Configuration
bits. The default device configuration is 7-Bit Address
Masking.
Both Masking modes, in turn, support address masking
of 7-bit and 10-bit addresses. The combination of
Masking modes and addresses provides different
ranges of Acknowledgable addresses for each
combination.
While both Masking modes function in roughly the
same manner, the way they use address masks are
different.
20.5.4.2 5-Bit Address Masking Mode
As the name implies, 5-Bit Address Masking mode
uses an address mask of up to 5 bits to create a range
of addresses to be Acknowledged, using bits, 5 through
1, of the incoming address. This allows the module to
Acknowledge up to 31 addresses when using 7-bit
addressing, or 63 addresses with 10-bit addressing
(see Example 20-3). This Masking mode is selected
when the MSSPMSK<2:1> Configuration bits are
programmed (‘00’).
The address mask in this mode is stored in the
SSPxCON2 register, which stops functioning as a con-
trol register in I2C Slave mode (Register 20-10). In 7-Bit
Address Masking mode, Address Mask bits, MSK<5:1>
(SSPxMSK<5:1>), mask the corresponding address
bits in the SSPxADD register. For any MSK bits that are
set (MSK<n> = 1), the corresponding address bit is
ignored (SSPxADD<n> = x). For the module to issue
an address Acknowledge, it is sufficient to match only
on addresses that do not have an active address mask.
In 10-Bit Address Masking mode, the MSK<5:2> bits
mask the corresponding address bits in the SSPxADD
register. In addition, MSK1 simultaneously masks the
two LSbs of the address (SSPxADD<1:0>). For any
MSKx bits that are active (MSK<n> = 1), the corre-
sponding address bit is ignored (SPxADD<n> = x).
Also note that although in 10-Bit Address Masking
mode, the upper address bits re-use part of the
SSPxADD register bits. The address mask bits do not
interact with those bits; they only affect the lower
address bits.
EXAMPLE 20-3: ADDRESS MASKING EXAMPLES IN 5-BIT MASKING MODE
Note 1: MSK1 masks the two Least Significant bits
of the address.
2: The two Most Significant bits of the
address are not affected by address
masking.
7-Bit Addressing:
SSPxADD<7:1> = A0h (1010000) (SSPxADD<0> is assumed to be ‘0’)
MSK<5:1> = 00111
Addresses Acknowledged: A0h, A2h, A4h, A6h, A8h, AAh, ACh, AEh
10-Bit Addressing:
SSPxADD<7:0> = A0h (10100000) (The two MSb of the address are ignored in this example, since
they are not affected by masking.)
MSK<5:1> = 00111
Addresses Acknowledged: A0h, A1h, A2h, A3h, A4h, A5h, A6h, A7h, A8h, A9h, AAh, ABh, ACh, ADh,
AEh, AFh
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DS30575A-page 382 2012 Microchip Technology Inc.
20.5.4.3 7-Bit Address Masking Mode
Unlike 5-bit masking, 7-Bit Address Masking mode
uses a mask of up to 8 bits (in 10-bit addressing) to
define a range of addresses that can be Acknowl-
edged, using the lowest bits of the incoming address.
This allows the module to Acknowledge up to
127 different addresses with 7-bit addressing, or 255
with 10-bit addressing (see Example 20-4). This mode
is the default configuration of the module, which is
selected when MSSPMSK<2:1> are unprogrammed
(‘1’).
The address mask for 7-Bit Address Masking mode is
stored in the SSPxMSK register, instead of the
SSPxCON2 register. SSPxMSK is a separate hard-
ware register within the module, but it is not directly
addressable. Instead, it shares an address in the SFR
space with the SSPxADD register. To access the
SSPxMSK register, it is necessary to select MSSP
mode, ‘1001’ (SSPxCON1<3:0> = 1001) and then
read or write to the location of SSPxADD.
To use 7-Bit Address Masking mode, it is necessary to
initialize SSPxMSK with a value before selecting the
I2C Slave Addressing mode. Thus, the required
sequence of events is:
1. Select SSPxMSK Access mode
(SSPxCON2<3:0> = 1001).
2. Write the mask value to the appropriate
SSPxADD register address (FC8h for MSSP1,
F6Eh for MSSP2).
3. Set the appropriate I2C Slave mode
(SSPxCON2<3:0> = 0111 for 10-bit
addressing, 0110 for 7-bit addressing).
Setting or clearing mask bits in SSPxMSK behaves in
the opposite manner of the MSKx bits in 5-Bit Address
Masking mode. That is, clearing a bit in SSPxMSK
causes the corresponding address bit to be masked;
setting the bit requires a match in that position.
SSPxMSK resets to all ‘1’s upon any Reset condition,
and therefore, has no effect on the standard MSSP
operation until written with a mask value.
With 7-bit addressing, SSPxMSK<7:1> bits mask the
corresponding address bits in the SSPxADD register.
For any SSPxMSK bits that are active
(SSPxMSK<n> = 0), the corresponding SSPxADD
address bit is ignored (SSPxADD<n> = x). For the
module to issue an address Acknowledge, it is
sufficient to match only on addresses that do not have
an active address mask.
With 10-bit addressing, SSPxMSK<7:0> bits mask the
corresponding address bits in the SSPxADD register.
For any SSPxMSK bits that are active (= 0), the corre-
sponding SSPxADD address bit is ignored
(SSPxADD<n> = x).
EXAMPLE 20-4: ADDRESS MASKING EXAMPLES IN 7-BIT MASKING MODE
Note: The two Most Significant bits of the
address are not affected by address
masking.
7-Bit Addressing:
SSPxADD<7:1> = 1010 000
SSPxMSK<7:1> = 1111 001
Addresses Acknowledged = ACh, A8h, A4h, A0h
10-Bit Addressing:
SSPxADD<7:0> = 1010 0000 (The two MSb are ignored in this example since they are not affected)
SSPxMSK<5:1> = 1111 0011
Addresses Acknowledged = ACh, A8h, A4h, A0h
2012 Microchip Technology Inc. DS30575A-page 383
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20.5.5 RECEPTION
When the R/W bit of the address byte is clear and an
address match occurs, the R/W bit of the SSPxSTAT
register is cleared. The received address is loaded into
the SSPxBUF register and the SDAx line is held low
(ACK).
When the address byte overflow condition exists, then
the no Acknowledge (ACK) pulse is given. An overflow
condition is defined if either bit, BF (SSPxSTAT<0>), is
set or bit, SSPOV (SSPxCON1<6>), is set.
An MSSPx interrupt is generated for each data transfer
byte. The interrupt flag bit, SSPxIF, must be cleared in
software. The SSPxSTAT register is used to determine
the status of the byte.
If SEN is enabled (SSPxCON2<0> = 1), SCLx will be
held low (clock stretch) following each data transfer.
The clock must be released by setting bit, CKP
(SSPxCON1<4>). See Section 20.5.7 “Clock
Stretching” for more details.
20.5.6 TRANSMISSION
When the R/W bit of the incoming address byte is set
and an address match occurs, the R/W bit of the
SSPxSTAT register is set. The received address is
loaded into the SSPxBUF register. The ACK pulse will
be sent on the ninth bit and pin, SCLx, is held low
regardless of SEN (see Section 20.5.7 “Clock
Stretching” for more details). By stretching the clock,
the master will be unable to assert another clock pulse
until the slave is done preparing the transmit data. The
transmit data must be loaded into the SSPxBUF regis-
ter which also loads the SSPxSR register. Then, pin,
SCLx, should be enabled by setting bit, CKP
(SSPxCON1<4>). The eight data bits are shifted out on
the falling edge of the SCLx input. This ensures that the
SDAx signal is valid during the SCLx high time
(Figure 20-10).
The ACK pulse from the master-receiver is latched on
the rising edge of the ninth SCLx input pulse. If the
SDAx line is high (not ACK), then the data transfer is
complete. In this case, when the ACK is latched by the
slave, the slave logic is reset and the slave monitors for
another occurrence of the Start bit. If the SDAx line was
low (ACK), the next transmit data must be loaded into
the SSPxBUF register. Again, pin SCLx must be
enabled by setting bit, CKP.
An MSSPx interrupt is generated for each data transfer
byte. The SSPxIF bit must be cleared in software and
the SSPxSTAT register is used to determine the status
of the byte. The SSPxIF bit is set on the falling edge of
the ninth clock pulse.
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DS30575A-page 384 2012 Microchip Technology Inc.
FIGURE 20-8: I2C™ SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 7-BIT ADDRESS)
SDAx
SCLx
SSPxIF (PIR1<3> or PIR3<7>)
BF (SSPxSTAT<0>)
SSPOV (SSPxCON1<6>)
S12345678912345678912345 789 P
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D1 D0
ACK
Receiving Data
ACK
Receiving Data
R/W = 0
ACK
Receiving Address
Cleared in software
SSPxBUF is read
Bus master
terminates
transfer
SSPOV is set
because SSPxBUF is
still full. ACK is not sent.
D2
6
CKP (SSPxCON<4>)
(CKP does not reset to ‘0’ when SEN = 0)
2012 Microchip Technology Inc. DS30575A-page 385
PIC18F97J94 FAMILY
FIGURE 20-9: I2C™ SLAVE MODE TIMING WITH SEN = 0 AND MSK<5:1> = 01011
(RECEPTION, 7-BIT ADDRESS)
SDAx
SCLx
SSPxIF (PIR1<3> or PIR3<7>)
BF (SSPxSTAT<0>)
SSPOV (SSPxCON1<6>)
S12345678912345678912345 789 P
A7 A6 A5 X A3 X X D7D6 D5D4D3D2D1 D0 D7D6D5D4D3 D1D0
ACK
Receiving Data
ACK
Receiving Data
R/W = 0
ACK
Receiving Address
Cleared in software
SSPxBUF is read
Bus master
terminates
transfer
SSPOV is set
because SSPxBUF is
still full. ACK is not sent.
D2
6
CKP (SSPxCON<4>)
(CKP does not reset to ‘0’ when SEN = 0)
Note 1: x = Don’t care (i.e., address bit can either be a ‘1’ or a ‘0’).
2: In this example, an address equal to A7.A6.A5.X.A3.X.X will be Acknowledged and cause
PIC18F97J94 FAMILY
DS30575A-page 386 2012 Microchip Technology Inc.
FIGURE 20-10: I2C™ SLAVE MODE TIMING (TRANSMISSION, 7-BIT ADDRESS)
SDAx
SCLx
BF (SSPxSTAT<0>)
A6 A5 A4 A3 A2 A1 D6 D5 D4 D3 D2 D1 D0
1 2 3 4 5 6 7 8 2 3 4 5 6 7 8 9
SSPxBUF is written in software
Cleared in software
Data in
sampled
S
ACK
Transmitting Data
R/W = 1
ACK
Receiving Address
A7 D7
91
D6 D5 D4 D3 D2 D1 D0
2 3 4 5 6 7 8 9
SSPxBUF is written in software
Cleared in software From SSPxIF ISR
Transmitting Data
D7
1
CKP (SSPxCON<4>)
P
ACK
CKP is set in software CKP is set in software
SCLx held low
while CPU
responds to SSPxIF
SSPxIF (PIR1<3> or PIR3<7>)
From SSPxIF ISR
Clear by reading
2012 Microchip Technology Inc. DS30575A-page 387
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FIGURE 20-11: I2C™ SLAVE MODE TIMING WITH SEN = 0 AND MSK<5:1> = 01001
(RECEPTION, 10-BIT ADDRESS)
SDAx
SCLx
SSPxIF (PIR1<3> or PIR3<7>)
BF (SSPxSTAT<0>)
S123456789 123456789 12345 789 P
1 1 1 1 0 A9 A8 A7 A6 A5 X A3 A2 X X D7 D6 D5 D4 D3 D1 D0
Receive Data Byte
ACK
R/W = 0
ACK
Receive First Byte of Address
Cleared in software
D2
6
Cleared in software
Receive Second Byte of Address
Cleared by hardware
when SSPxADD is updated
with low byte of address
UA (SSPxSTAT<1>)
Clock is held low until
update of SSPxADD has
taken place
UA is set indicating that
the SSPxADD needs to be
updated
UA is set indicating that
SSPxADD needs to be
updated
Cleared by hardware when
SSPxADD is updated with high
byte of address
SSPxBUF is written with
contents of SSPxSR
Dummy read of SSPxBUF
to clear BF flag
ACK
CKP (SSPxCON<4>)
12345 789
D7 D6 D5 D4 D3 D1 D0
Receive Data Byte
Bus master
terminates
transfer
D2
6
ACK
Cleared in software Cleared in software
SSPOV (SSPxCON1<6>)
SSPOV is set
because SSPxBUF is
still full. ACK is not sent.
(CKP does not reset to ‘0’ when SEN = 0)
Clock is held low until
update of SSPxADD has
taken place
Note 1: x = Don’t care (i.e., address bit can either be a ‘1’ or a ‘0’).
2: In this example, an address equal to A9.A8.A7.A6.A5.X.A3.A2.X.X will be Acknowledged
and cause an interrupt.
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DS30575A-page 388 2012 Microchip Technology Inc.
FIGURE 20-12: I2C™ SLAVE MODE TIMING WITH SEN = 0 (RECEPTION, 10-BIT ADDRESS)
SDAx
SCLx
SSPxIF (PIR1<3> or PIR3<7>)
BF (SSPxSTAT<0>)
S123456789 123456789 12345 789 P
1 1 1 1 0 A9 A8 A7 A6A5 A4A3A2A1 A0 D7 D6D5D4D3 D1D0
Receive Data Byte
ACK
R/W = 0
ACK
Receive First Byte of Address
Cleared in software
D2
6
Cleared in software
Receive Second Byte of Address
Cleared by hardware
when SSPxADD is updated
with low byte of address
UA (SSPxSTAT<1>)
Clock is held low until
update of SSPxADD has
taken place
UA is set indicating that
the SSPxADD needs to be
updated
UA is set indicating that
SSPxADD needs to be
updated
Cleared by hardware when
SSPxADD is updated with high
byte of address
SSPxBUF is written with
contents of SSPxSR
Dummy read of SSPxBUF
to clear BF flag
ACK
CKP (SSPxCON<4>)
12345 789
D7 D6 D5 D4 D3 D1 D0
Receive Data Byte
Bus master
terminates
transfer
D2
6
ACK
Cleared in software Cleared in software
SSPOV (SSPxCON1<6>)
SSPOV is set
because SSPxBUF is
still full. ACK is not sent.
(CKP does not reset to ‘0’ when SEN = 0)
Clock is held low until
update of SSPxADD has
taken place
2012 Microchip Technology Inc. DS30575A-page 389
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FIGURE 20-13: I2C™ SLAVE MODE TIMING (TRANSMISSION, 10-BIT ADDRESS)
SDAx
SCLx
SSPxIF (PIR1<3> or PIR3<7>)
BF (SSPxSTAT<0>)
S1234 5 6789 1 23 45 678 9 12345 7 89 P
1 1 1 1 0 A9A8 A7 A6A5A4A3A2A1A0 1 1 1 1 0 A8
R/W = 1
ACK
ACK
R/W = 0
ACK
Receive First Byte of Address
Cleared in software
Bus master
terminates
transfer
A9
6
Receive Second Byte of Address
Cleared by hardware when
SSPxADD is updated with low
byte of address
UA (SSPxSTAT<1>)
Clock is held low until
update of SSPxADD has
taken place
UA is set indicating that
the SSPxADD needs to be
updated
UA is set indicating that
SSPxADD needs to be
updated
Cleared by hardware when
SSPxADD is updated with high
byte of address.
SSPxBUF is written with
contents of SSPxSR
Dummy read of SSPxBUF
to clear BF flag
Receive First Byte of Address
12345 789
D7 D6 D5 D4 D3 D1
ACK
D2
6
Transmitting Data Byte
D0
Dummy read of SSPxBUF
to clear BF flag
Sr
Cleared in software
Write of SSPxBUF
initiates transmit
Cleared in software
Completion of
clears BF flag
CKP (SSPxCON1<4>)
CKP is set in software
CKP is automatically cleared in hardware, holding SCLx low
Clock is held low until
update of SSPxADD has
taken place
data transmission
Clock is held low until
CKP is set to ‘1’
third address sequence
BF flag is clear
at the end of the
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DS30575A-page 390 2012 Microchip Technology Inc.
20.5.7 CLOCK STRETCHING
Both 7-Bit and 10-Bit Slave modes implement
automatic clock stretching during a transmit sequence.
The SEN bit (SSPxCON2<0>) allows clock stretching
to be enabled during receives. Setting SEN will cause
the SCLx pin to be held low at the end of each data
receive sequence.
20.5.7.1 Clock Stretching for 7-Bit Slave
Receive Mode (SEN = 1)
In 7-Bit Slave Receive mode, on the falling edge of the
ninth clock at the end of the ACK sequence, if the BF
bit is set, the CKP bit in the SSPxCON1 register is auto-
matically cleared, forcing the SCLx output to be held
low. The CKP bit, being cleared to ‘0’, will assert the
SCLx line low. The CKP bit must be set in the user’s
ISR before reception is allowed to continue. By holding
the SCLx line low, the user has time to service the ISR
and read the contents of the SSPxBUF before the mas-
ter device can initiate another receive sequence. This
will prevent buffer overruns from occurring (see
Figure 20-15).
20.5.7.2 Clock Stretching for 10-Bit Slave
Receive Mode (SEN = 1)
In 10-Bit Slave Receive mode, during the address
sequence, clock stretching automatically takes place
but CKP is not cleared. During this time, if the UA bit is
set after the ninth clock, clock stretching is initiated.
The UA bit is set after receiving the upper byte of the
10-bit address, and following the receive of the second
byte of the 10-bit address, with the R/W bit cleared to
‘0’. The release of the clock line occurs upon updating
SSPxADD. Clock stretching will occur on each data
receive sequence as described in 7-bit mode.
20.5.7.3 Clock Stretching for 7-Bit Slave
Transmit Mode
The 7-Bit Slave Transmit mode implements clock
stretching by clearing the CKP bit after the falling edge
of the ninth clock if the BF bit is clear. This occurs
regardless of the state of the SEN bit.
The user’s ISR must set the CKP bit before transmis-
sion is allowed to continue. By holding the SCLx line
low, the user has time to service the ISR and load the
contents of the SSPxBUF before the master device can
initiate another transmit sequence (see Figure 20-10).
20.5.7.4 Clock Stretching for 10-Bit Slave
Transmit Mode
In 10-Bit Slave Transmit mode, clock stretching is
controlled during the first two address sequences by
the state of the UA bit, just as it is in 10-Bit Slave
Receive mode. The first two addresses are followed by
a third address sequence, which contains the high-
order bits of the 10-bit address and the R/W bit set to
‘1’. After the third address sequence is performed, the
UA bit is not set, the module is now configured in
Transmit mode and clock stretching is controlled by
the BF flag as in 7-Bit Slave Transmit mode (see
Figure 20-13).
Note 1: If the user reads the contents of the
SSPxBUF before the falling edge of the
ninth clock, thus clearing the BF bit, the
CKP bit will not be cleared and clock
stretching will not occur.
2: The CKP bit can be set in software
regardless of the state of the BF bit. The
user should be careful to clear the BF bit
in the ISR before the next receive
sequence in order to prevent an overflow
condition.
Note: If the user polls the UA bit and clears it by
updating the SSPxADD register before the
falling edge of the ninth clock occurs, and
if the user hasn’t cleared the BF bit by
reading the SSPxBUF register before that
time, then the CKP bit will still NOT be
asserted low. Clock stretching, on the
basis of the state of the BF bit, only occurs
during a data sequence, not an address
sequence.
Note 1: If the user loads the contents of
SSPxBUF, setting the BF bit before the
falling edge of the ninth clock, the CKP bit
will not be cleared and clock stretching
will not occur.
2: The CKP bit can be set in software,
regardless of the state of the BF bit.
2012 Microchip Technology Inc. DS30575A-page 391
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20.5.7.5 Clock Synchronization and
the CKP bit
When the CKP bit is cleared, the SCLx output is forced
to ‘0’. However, clearing the CKP bit will not assert the
SCLx output low until the SCLx output is already
sampled low. Therefore, the CKP bit will not assert the
SCLx line until an external I2C master device has
already asserted the SCLx line. The SCLx output will
remain low until the CKP bit is set and all other devices
on the I2C bus have deasserted SCLx. This ensures
that a write to the CKP bit will not violate the minimum
high time requirement for SCLx (see Figure 20-14).
FIGURE 20-14: CLOCK SYNCHRONIZATION TIMING
SDAx
SCLx
DX – 1
DX
WR
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
SSPxCON1
CKP
Master Device
Deasserts Clock
Master Device
Asserts Clock
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DS30575A-page 392 2012 Microchip Technology Inc.
FIGURE 20-15: I2C™ SLAVE MODE TIMING WITH SEN = 1 (RECEPTION, 7-BIT ADDRESS)
SDAx
SCLx
SSPxIF (PIR1<3> or PIR3<7>)
BF (SSPxSTAT<0>)
SSPOV (SSPxCON1<6>)
S1 234 567 89 1 2345 67 89 1 23 45 7 89 P
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D1 D0
ACK
Receiving Data
ACK
Receiving Data
R/W = 0
ACK
Receiving Address
Cleared in software
SSPxBUF is read
Bus master
terminates
transfer
SSPOV is set
because SSPxBUF is
still full. ACK is not sent.
D2
6
CKP (SSPxCON<4>)
CKP
written
to ‘1’ in
If BF is cleared
prior to the falling
edge of the 9th clock,
CKP will not be reset
to ‘0’ and no clock
stretching will occur
software
Clock is held low until
CKP is set to ‘1’
Clock is not held low
because buffer full bit is
clear prior to falling edge
of 9th clock
Clock is not held low
because ACK = 1
BF is set after falling
edge of the 9th clock,
CKP is reset to ‘0’ and
clock stretching occurs
2012 Microchip Technology Inc. DS30575A-page 393
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FIGURE 20-16: I2C™ SLAVE MODE TIMING WITH SEN = 1 (RECEPTION, 10-BIT ADDRESS)
SDAx
SCLx
SSPxIF (PIR1<3> or PIR3<7>)
BF (SSPxSTAT<0>)
S123456789 123456789 12345 789 P
1 1 1 1 0 A9A8 A7 A6A5A4A3A2A1 A0 D7D6D5D4D3 D1D0
Receive Data Byte
ACK
R/W = 0
ACK
Receive First Byte of Address
Cleared in software
D2
6
Cleared in software
Receive Second Byte of Address
Cleared by hardware when
SSPxADD is updated with low
byte of address after falling edge
UA (SSPxSTAT<1>)
Clock is held low until
update of SSPxADD has
taken place
UA is set indicating that
the SSPxADD needs to be
updated
UA is set indicating that
SSPxADD needs to be
updated
Cleared by hardware when
SSPxADD is updated with high
byte of address after falling edge
SSPxBUF is written with
contents of SSPxSR Dummy read of SSPxBUF
to clear BF flag
ACK
CKP (SSPxCON<4>)
12345 789
D7 D6 D5 D4 D3 D1 D0
Receive Data Byte
Bus master
terminates
transfer
D2
6
ACK
Cleared in software Cleared in software
SSPOV (SSPxCON1<6>)
CKP written to ‘1’
Note: An update of the
SSPxADD register before
Note: An update of
the SSPxADD
register in software
Clock is held low until
update of SSPxADD has
taken place
of ninth clock
of ninth clock
SSPOV is set
because SSPxBUF is
still full. ACK is not sent.
Dummy read of SSPxBUF
to clear BF flag
Clock is held low until
CKP is set to ‘1’
Clock is not held low
because ACK = 1
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DS30575A-page 394 2012 Microchip Technology Inc.
20.5.8 GENERAL CALL ADDRESS
SUPPORT
The addressing procedure for the I2C bus is such that
the first byte after the Start condition usually
determines which device will be the slave addressed by
the master. The exception is the general call address
which can address all devices. When this address is
used, all devices should, in theory, respond with an
Acknowledge.
The general call address is one of eight addresses
reserved for specific purposes by the I2C protocol. It
consists of all ‘0’s with R/W = 0.
The general call address is recognized when the
General Call Enable bit, GCEN, is enabled
(SSPxCON2<7> set). Following a Start bit detect, eight
bits are shifted into the SSPxSR and the address is
compared against the SSPxADD. It is also compared to
the general call address and fixed in hardware.
If the general call address matches, the SSPxSR is
transferred to the SSPxBUF, the BF flag bit is set
(eighth bit), and on the falling edge of the ninth bit (ACK
bit), the SSPxIF interrupt flag bit is set.
When the interrupt is serviced, the source for the
interrupt can be checked by reading the contents of the
SSPxBUF. The value can be used to determine if the
address was device-specific or a general call address.
In 10-Bit Addressing mode, the SSPxADD is required to
be updated for the second half of the address to match
and the UA bit is set (SSPxSTAT<1>). If the general call
address is sampled when the GCEN bit is set, while the
slave is configured in 10-Bit Addressing mode, then the
second half of the address is not necessary, the UA bit
will not be set and the slave will begin receiving data
after the Acknowledge (Figure 20-17).
FIGURE 20-17: SLAVE MODE GENERAL CALL ADDRESS SEQUENCE
(7 OR 10-BIT ADDRESSING MODE)
SDAx
SCLx
S
SSPxIF
BF (SSPxSTAT<0>)
SSPOV (SSPxCON1<6>)
Cleared in Software
SSPxBUF is Read
R/W = 0
ACK
General Call Address
Address is Compared to General Call Address
GCEN (SSPxCON2<7>)
Receiving Data ACK
123456789123456789
D7 D6 D5 D4 D3 D2 D1 D0
After ACK, Set Interrupt
‘0’
‘1’
2012 Microchip Technology Inc. DS30575A-page 395
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20.5.9 MASTER MODE
Master mode is enabled by setting and clearing the
appropriate SSPMx bits in SSPxCON1, and by setting
the SSPEN bit. In Master mode, the SCLx and SDAx
lines are manipulated by the MSSPx hardware if the
TRIS bits are set.
The Master mode of operation is supported by interrupt
generation on the detection of the Start and Stop
conditions. The Stop (P) and Start (S) bits are cleared
from a Reset or when the MSSPx module is disabled.
Control of the I2C bus may be taken when the P bit is
set, or the bus is Idle, with both the S and P bits clear.
In Firmware Controlled Master mode, user code
conducts all I2C bus operations based on Start and
Stop bit conditions.
Once Master mode is enabled, the user has six
options.
1. Assert a Start condition on SDAx and SCLx.
2. Assert a Repeated Start condition on SDAx and
SCLx.
3. Write to the SSPxBUF register initiating
transmission of data/address.
4. Configure the I2C port to receive data.
5. Generate an Acknowledge condition at the end
of a received byte of data.
6. Generate a Stop condition on SDAx and SCLx.
The following events will cause the MSSPx Interrupt
Flag bit, SSPxIF, to be set (and MSSPx interrupt if
enabled):
• Start condition
• Stop condition
• Data transfer byte transmitted/received
• Acknowledge transmitted
• Repeated Start
FIGURE 20-18: MSSPx BLOCK DIAGRAM (I2C™ MASTER MODE)
Note: The MSSPx module, when configured in
I2C Master mode, does not allow queueing
of events. For instance, the user is not
allowed to initiate a Start condition and
immediately write the SSPxBUF register
to initiate transmission before the Start
condition is complete. In this case, the
SSPxBUF will not be written to and the
WCOL bit will be set, indicating that a write
to the SSPxBUF did not occur.
Read Write
SSPxSR
Start bit, Stop bit,
SSPxBUF
Internal
Data Bus
Set/Reset S, P (SSPxSTAT), WCOL (SSPxCON1);
Shift
Clock
MSb LSb
SDAx
Acknowledge
Generate
Stop bit Detect
Write Collision Detect
Clock Arbitration
State Counter for
End of XMIT/RCV
SCLx
SCLx In
Bus Collision
SDAx In
Receive Enable
Clock Cntl
Clock Arbitrate/WCOL Detect
(hold off clock source)
SSPxADD<6:0>
Baud
Set SSPxIF, BCLxIF;
Reset ACKSTAT, PEN (SSPxCON2)
Rate
Generator
SSPM<3:0>
Start bit Detect
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20.5.9.1 I2C™ Master Mode Operation
The master device generates all of the serial clock
pulses and the Start and Stop conditions. A transfer is
ended with a Stop condition or with a Repeated Start
condition. Since the Repeated Start condition is also
the beginning of the next serial transfer, the I2C bus will
not be released.
In Master Transmitter mode, serial data is output
through SDAx while SCLx outputs the serial clock. The
first byte transmitted contains the slave address of the
receiving device (7 bits) and the Read/Write (R/W) bit.
In this case, the R/W bit will be logic ‘0’. Serial data is
transmitted, 8 bits at a time. After each byte is transmit-
ted, an Acknowledge bit is received. Start and Stop
conditions are output to indicate the beginning and the
end of a serial transfer.
In Master Receive mode, the first byte transmitted
contains the slave address of the transmitting device
(7 bits) and the R/W bit. In this case, the R/W bit will be
logic ‘1’. Thus, the first byte transmitted is a 7-bit slave
address, followed by a ‘1’ to indicate the receive bit.
Serial data is received via SDAx, while SCLx outputs
the serial clock. Serial data is received, 8 bits at a time.
After each byte is received, an Acknowledge bit is
transmitted. Start and Stop conditions indicate the
beginning and end of transmission.
The Baud Rate Generator, used for the SPI mode
operation, is used to set the SCLx clock frequency for
either 100 kHz, 400 kHz or 1 MHz I2C operation. See
Section 20.5.10 “Baud Rate” for more details.
A typical transmit sequence would go as follows:
1. The user generates a Start condition by setting
the Start Enable bit, SEN (SSPxCON2<0>).
2. SSPxIF is set. The MSSPx module will wait the
required start time before any other operation
takes place.
3. The user loads the SSPxBUF with the slave
address to transmit.
4. Address is shifted out the SDAx pin until all 8 bits
are transmitted.
5. The MSSPx module shifts in the ACK bit from
the slave device and writes its value into the
SSPxCON2 register (SSPxCON2<6>).
6. The MSSPx module generates an interrupt at
the end of the ninth clock cycle by setting the
SSPxIF bit.
7. The user loads the SSPxBUF with eight bits of
data.
8. Data is shifted out the SDAx pin until all 8 bits
are transmitted.
9. The MSSPx module shifts in the ACK bit from
the slave device and writes its value into the
SSPxCON2 register (SSPxCON2<6>).
10. The MSSPx module generates an interrupt at
the end of the ninth clock cycle by setting the
SSPxIF bit.
11. The user generates a Stop condition by setting
the Stop Enable bit, PEN (SSPxCON2<2>).
12. Interrupt is generated once the Stop condition is
complete.
2012 Microchip Technology Inc. DS30575A-page 397
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20.5.10 BAUD RATE
In I2C Master mode, the Baud Rate Generator (BRG)
reload value is placed in the lower 7 bits of the
SSPxADD register (Figure 20-19). When a write
occurs to SSPxBUF, the Baud Rate Generator will
automatically begin counting. The BRG counts down to
0 and stops until another reload has taken place. The
BRG count is decremented, twice per instruction cycle
(T
CY), on the Q2 and Q4 clocks. In I2C Master mode,
the BRG is reloaded automatically.
Once the given operation is complete (i.e., transmis-
sion of the last data bit is followed by ACK), the internal
clock will automatically stop counting and the SCLx pin
will remain in its last state.
Table 20-2 demonstrates clock rates based on
instruction cycles and the BRG value loaded into
SSPxADD. The SSPxADD BRG value of ‘0x00’ is not
supported.
20.5.10.1 Baud Rate and Module
Interdependence
Because MSSP1 and MSSP2 are independent, they
can operate simultaneously in I2C Master mode at
different baud rates. This is done by using different
BRG reload values for each module.
Because this mode derives its basic clock source from
the system clock, any changes to the clock will affect
both modules in the same proportion. It may be
possible to change one or both baud rates back to a
previous value by changing the BRG reload value.
FIGURE 20-19: BAUD RATE GENERATOR BLOCK DIAGRAM
TABLE 20-2: I2C™ CLOCK RATE w/BRG
SSPM<3:0>
BRG Down Counter
CLKO FOSC/4
SSPxADD<6:0>
SSPM<3:0>
SCLx
Reload
Control
Reload
FOSC FCY FCY * 2 BRG Value FSCL
(2 Rollovers of BRG)
64 MHz 16 MHz 32 MHz 27h 400 kHz(1)
64 MHz 16 MHz 32 MHz 32h 313.72 kHz
64 MHz 16 MHz 32 MHz 9Fh 100 kHz
16 MHz 4 MHz 8 MHz 09h 400 kHz(1)
16 MHz 4 MHz 8 MHz 0Ch 308 kHz
16 MHz 4 MHz 8 MHz 27h 100 kHz
4 MHz 1 MHz 2 MHz 02h 333 kHz(1)
4 MHz 1 MHz 2 MHz 09h 100 kHz
16 MHz 4 MHz 8 MHz 03h 1 MHz(1,2)
Note 1: The I2C interface does not conform to the 400 kHz I2C specification (which applies to rates greater than
100 kHz) in all details, but may be used with care where higher rates are required by the application.
2: A minimum of 16 MHz FOSC is required to get 1 MHz I2C.
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20.5.10.2 Clock Arbitration
Clock arbitration occurs when the master, during any
receive, transmit or Repeated Start/Stop condition,
deasserts the SCLx pin (SCLx allowed to float high).
When the SCLx pin is allowed to float high, the Baud
Rate Generator (BRG) is suspended from counting
until the SCLx pin is actually sampled high. When the
SCLx pin is sampled high, the Baud Rate Generator is
reloaded with the contents of SSPxADD<6:0> and
begins counting. This ensures that the SCLx high time
will always be at least one BRG rollover count in the
event that the clock is held low by an external device
(Figure 20-20).
FIGURE 20-20: BAUD RATE GENERATOR TIMING WITH CLOCK ARBITRATION
SDAx
SCLx
SCLx Deasserted but Slave Holds
DX – 1DX
BRG
SCLx is Sampled High, Reload takes
place and BRG Starts its Count
03h 02h 01h 00h (hold off) 03h 02h
Reload
BRG
Value
SCLx Low (clock arbitration)
SCLx Allowed to Transition High
BRG Decrements on
Q2 and Q4 Cycles
2012 Microchip Technology Inc. DS30575A-page 399
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20.5.11 I2C™ MASTER MODE START
CONDITION TIMING
To initiate a Start condition, the user sets the Start
Enable bit, SEN (SSPxCON2<0>). If the SDAx and
SCLx pins are sampled high, the Baud Rate Generator
is reloaded with the contents of SSPxADD<6:0> and
starts its count. If SCLx and SDAx are both sampled
high when the Baud Rate Generator times out (TBRG),
the SDAx pin is driven low. The action of the SDAx
being driven low while SCLx is high is the Start condi-
tion and causes the S bit (SSPxSTAT<3>) to be set.
Following this, the Baud Rate Generator is reloaded
with the contents of SSPxADD<6:0> and resumes its
count. When the Baud Rate Generator times out
(TBRG), the SEN bit (SSPxCON2<0>) will be
automatically cleared by hardware. The Baud Rate
Generator is suspended, leaving the SDAx line held low
and the Start condition is complete.
20.5.11.1 WCOL Status Flag
If the user writes the SSPxBUF when a Start sequence
is in progress, the WCOL bit is set and the contents of
the buffer are unchanged (the write doesn’t occur).
FIGURE 20-21: FIRST START BIT TIMING
Note: If, at the beginning of the Start condition,
the SDAx and SCLx pins are already
sampled low, or if during the Start condi-
tion, the SCLx line is sampled low before
the SDAx line is driven low, a bus collision
occurs, the Bus Collision Interrupt Flag,
BCLxIF, is set, the Start condition is
aborted and the I2C module is reset into its
Idle state.
Note: Because queueing of events is not
allowed, writing to the lower 5 bits of
SSPxCON2 is disabled until the Start
condition is complete.
SDAx
SCLx
S
TBRG
1st bit 2nd bit
TBRG
SDAx = 1, At Completion of Start bit,
SCLx = 1
Write to SSPxBUF Occurs Here
TBRG
Hardware Clears SEN bit
TBRG
Write to SEN bit Occurs Here Set S bit (SSPxSTAT<3>)
and Sets SSPxIF bit
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DS30575A-page 400 2012 Microchip Technology Inc.
20.5.12 I2C™ MASTER MODE REPEATED
START CONDITION TIMING
A Repeated Start condition occurs when the RSEN bit
(SSPxCON2<1>) is programmed high and the I2C logic
module is in the Idle state. When the RSEN bit is set,
the SCLx pin is asserted low. When the SCLx pin is
sampled low, the Baud Rate Generator is loaded with
the contents of SSPxADD<5:0> and begins counting.
The SDAx pin is released (brought high) for one Baud
Rate Generator count (TBRG). When the Baud Rate
Generator times out, and if SDAx is sampled high, the
SCLx pin will be deasserted (brought high). When
SCLx is sampled high, the Baud Rate Generator is
reloaded with the contents of SSPxADD<6:0> and
begins counting. SDAx and SCLx must be sampled
high for one TBRG. This action is then followed by
assertion of the SDAx pin (SDAx = 0) for one TBRG
while SCLx is high. Following this, the RSEN bit
(SSPxCON2<1>) will be automatically cleared and the
Baud Rate Generator will not be reloaded, leaving the
SDAx pin held low. As soon as a Start condition is
detected on the SDAx and SCLx pins, the S bit
(SSPxSTAT<3>) will be set. The SSPxIF bit will not be
set until the Baud Rate Generator has timed out.
Immediately following the SSPxIF bit getting set, the
user may write the SSPxBUF with the 7-bit address in
7-bit mode or the default first address in 10-bit mode.
After the first eight bits are transmitted and an ACK is
received, the user may then transmit an additional eight
bits of address (10-bit mode) or eight bits of data (7-bit
mode).
20.5.12.1 WCOL Status Flag
If the user writes the SSPxBUF when a Repeated Start
sequence is in progress, the WCOL is set and the
contents of the buffer are unchanged (the write doesn’t
occur).
FIGURE 20-22: REPEATED START CONDITION WAVEFORM
Note 1: If RSEN is programmed while any other
event is in progress, it will not take effect.
2: A bus collision during the Repeated Start
condition occurs if:
• SDAx is sampled low when SCLx
goes from low-to-high.
• SCLx goes low before SDAx is
asserted low. This may indicate that
another master is attempting to
transmit a data ‘1’.
Note: Because queueing of events is not
allowed, writing of the lower 5 bits of
SSPxCON2 is disabled until the Repeated
Start condition is complete.
SDAx
SCLx
Sr = Repeated Start
Write to SSPxCON2 Occurs Here:
Write to SSPxBUF Occurs Here
on Falling Edge of Ninth Clock,
End of XMIT
At Completion of Start bit,
Hardware Clears RSEN bit
1st bit
S bit Set by Hardware
TBRG
SDAx = 1,
SDAx = 1,
SCLx (no change).
SCLx = 1
and Sets SSPxIF
RSEN bit Set by Hardware
TBRG
TBRG TBRG TBRG
2012 Microchip Technology Inc. DS30575A-page 401
PIC18F97J94 FAMILY
20.5.13 I2C™ MASTER MODE
TRANSMISSION
Transmission of a data byte, a 7-bit address or the
other half of a 10-bit address, is accomplished by
simply writing a value to the SSPxBUF register. This
action will set the Buffer Full flag bit, BF, and allow the
Baud Rate Generator to begin counting and start the
next transmission. Each bit of address/data will be
shifted out onto the SDAx pin after the falling edge of
SCLx is asserted (see data hold time specification
Parameter 106). SCLx is held low for one Baud Rate
Generator rollover count (TBRG). Data should be valid
before SCLx is released high (see data setup time
specification Parameter 107). When the SCLx pin is
released high, it is held that way for TBRG. The data on
the SDAx pin must remain stable for that duration and
some hold time after the next falling edge of SCLx.
After the eighth bit is shifted out (the falling edge of the
eighth clock), the BF flag is cleared and the master
releases SDAx. This allows the slave device being
addressed to respond with an ACK bit during the ninth
bit time if an address match occurred, or if data was
received properly. The status of ACK is written into the
ACKDT bit on the falling edge of the ninth clock. If the
master receives an Acknowledge, the Acknowledge
Status bit, ACKSTAT, is cleared; if not, the bit is set.
After the ninth clock, the SSPxIF bit is set and the
master clock (Baud Rate Generator) is suspended until
the next data byte is loaded into the SSPxBUF, leaving
SCLx low and SDAx unchanged (Figure 20-23).
After the write to the SSPxBUF, each bit of the address
will be shifted out on the falling edge of SCLx until all
seven address bits and the R/W bit are completed. On
the falling edge of the eighth clock, the master will
deassert the SDAx pin, allowing the slave to respond
with an Acknowledge. On the falling edge of the ninth
clock, the master will sample the SDAx pin to see if the
address was recognized by a slave. The status of the
ACK bit is loaded into the ACKSTAT status bit
(SSPxCON2<6>). Following the falling edge of the
ninth clock transmission of the address, the SSPxIF
flag is set, the BF flag is cleared and the Baud Rate
Generator is turned off until another write to the
SSPxBUF takes place, holding SCLx low and allowing
SDAx to float.
20.5.13.1 BF Status Flag
In Transmit mode, the BF bit (SSPxSTAT<0>) is set
when the CPU writes to SSPxBUF and is cleared when
all 8 bits are shifted out.
20.5.13.2 WCOL Status Flag
If the user writes the SSPxBUF when a transmit is
already in progress (i.e., SSPxSR is still shifting out a
data byte), the WCOL bit is set and the contents of the
buffer are unchanged (the write doesn’t occur) after
2T
CY after the SSPxBUF write. If SSPxBUF is rewritten
within 2 TCY, the WCOL bit is set and SSPxBUF is
updated. This may result in a corrupted transfer.
The user should verify that the WCOL bit is clear after
each write to SSPxBUF to ensure the transfer is
correct. In all cases, WCOL must be cleared in
software.
20.5.13.3 ACKSTAT Status Flag
In Transmit mode, the ACKSTAT bit (SSPxCON2<6>)
is cleared when the slave has sent an Acknowledge
(ACK =0) and is set when the slave does not Acknowl-
edge (ACK = 1). A slave sends an Acknowledge when
it has recognized its address (including a general call),
or when the slave has properly received its data.
20.5.14 I2C™ MASTER MODE RECEPTION
Master mode reception is enabled by programming the
Receive Enable bit, RCEN (SSPxCON2<3>).
The Baud Rate Generator begins counting, and on
each rollover, the state of the SCLx pin changes (high-
to-low/low-to-high) and data is shifted into the
SSPxSR. After the falling edge of the eighth clock, the
receive enable flag is automatically cleared, the con-
tents of the SSPxSR are loaded into the SSPxBUF, the
BF flag bit is set, the SSPxIF flag bit is set and the Baud
Rate Generator is suspended from counting, holding
SCLx low. The MSSPx is now in Idle state awaiting the
next command. When the buffer is read by the CPU,
the BF flag bit is automatically cleared. The user can
then send an Acknowledge bit at the end of reception
by setting the Acknowledge Sequence Enable bit,
ACKEN (SSPxCON2<4>).
20.5.14.1 BF Status Flag
In receive operation, the BF bit is set when an address
or data byte is loaded into SSPxBUF from SSPxSR. It
is cleared when the SSPxBUF register is read.
20.5.14.2 SSPOV Status Flag
In receive operation, the SSPOV bit is set when 8 bits
are received into the SSPxSR and the BF flag bit is
already set from a previous reception.
20.5.14.3 WCOL Status Flag
If the user writes the SSPxBUF when a receive is
already in progress (i.e., SSPxSR is still shifting in a
data byte), the WCOL bit is set and the contents of the
buffer are unchanged (the write doesn’t occur).
Note: The MSSPx module must be in an inactive
state before the RCEN bit is set or the
RCEN bit will be disregarded.
PIC18F97J94 FAMILY
DS30575A-page 402 2012 Microchip Technology Inc.
FIGURE 20-23: I2C™ MASTER MODE WAVEFORM (TRANSMISSION, 7 OR 10-BIT ADDRESS)
SDAx
SCLx
SSPxIF
BF (SSPxSTAT<0>)
SEN
A7 A6 A5 A4 A3 A2 A1 ACK = 0D7 D6 D5 D4 D3 D2 D1 D0
ACK
Transmitting Data or Second Half
R/W = 0Transmit Address to Slave
123456789 123456789 P
Cleared in software service routine
SSPxBUF is written in software
from MSSPx interrupt
After Start condition, SEN cleared by hardware
S
SSPxBUF written with 7-bit address and R/W,
start transmit
SCLx held low
while CPU
responds to SSPxIF
SEN = 0
of 10-bit Address
Write SSPxCON2<0> (SEN = 1),
Start condition begins From slave, clear ACKSTAT bit (SSPxCON2<6>)
ACKSTAT in
SSPxCON2 = 1
Cleared in software
SSPxBUF written
PEN
R/W
Cleared in software
2012 Microchip Technology Inc. DS30575A-page 403
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FIGURE 20-24: I2C™ MASTER MODE WAVEFORM (RECEPTION, 7-BIT ADDRESS)
P
9
87
6
5
D0
D1
D2
D3D4
D5
D6D7
S
A7 A6 A5 A4 A3 A2 A1
SDAx
SCLx 12
345678912345678 9 1234
Bus master
terminates
transfer
ACK
Receiving Data from Slave
Receiving Data from Slave
D0
D1
D2
D3D4
D5
D6D7
ACK
R/W = 1
Transmit Address to Slave
SSPxIF
BF
ACK is not sent
Write to SSPxCON2<0> (SEN = 1),
Write to SSPxBUF occurs here, ACK from Slave
Master configured as a receiver
by programming SSPxCON2<3> (RCEN = 1)
PEN bit = 1
written here
Data shifted in on falling edge of CLK
Cleared in software
start XMIT
SEN = 0
SSPOV
SDAx = 0, SCLx = 1,
while CPU
(SSPxSTAT<0>)
ACK
Cleared in software
Cleared in software
Set SSPxIF interrupt
at end of receive
Set P bit
(SSPxSTAT<4>)
and SSPxIF
ACK from master,
Set SSPxIF at end
Set SSPxIF interrupt
at end of Acknowledge
sequence
Set SSPxIF interrupt
at end of Acknowledge
sequence
of receive
Set ACKEN, start Acknowledge sequence,
SDAx = ACKDT = 1
RCEN cleared
automatically
RCEN = 1, start
next receive
Write to SSPxCON2<4>
to start Acknowledge sequence,
SDAx = ACKDT (SSPxCON2<5>) = 0
RCEN cleared
automatically
responds to SSPxIF
ACKEN
begin Start condition
Cleared in software
SDAx = ACKDT = 0
Last bit is shifted into SSPxSR and
contents are unloaded into SSPxBUF
Cleared in
software
SSPOV is set because
SSPxBUF is still full
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DS30575A-page 404 2012 Microchip Technology Inc.
20.5.15 ACKNOWLEDGE SEQUENCE
TIMING
An Acknowledge sequence is enabled by setting the
Acknowledge Sequence Enable bit, ACKEN
(SSPxCON2<4>). When this bit is set, the SCLx pin is
pulled low and the contents of the Acknowledge data bit
are presented on the SDAx pin. If the user wishes to gen-
erate an Acknowledge, then the ACKDT bit should be
cleared. If not, the user should set the ACKDT bit before
starting an Acknowledge sequence. The Baud Rate Gen-
erator then counts for one rollover period (TBRG) and the
SCLx pin is deasserted (pulled high). When the SCLx pin
is sampled high (clock arbitration), the Baud Rate Gener-
ator counts for TBRG; the SCLx pin is then pulled low.
Following this, the ACKEN bit is automatically cleared, the
Baud Rate Generator is turned off and the MSSPx
module then goes into an inactive state (Figure 20-25).
20.5.15.1 WCOL Status Flag
If the user writes the SSPxBUF when an Acknowledge
sequence is in progress, then WCOL is set and the
contents of the buffer are unchanged (the write doesn’t
occur).
20.5.16 STOP CONDITION TIMING
A Stop bit is asserted on the SDAx pin at the end of a
receive/transmit by setting the Stop Sequence Enable
bit, PEN (SSPxCON2<2>). At the end of a receive/
transmit, the SCLx line is held low after the falling edge
of the ninth clock. When the PEN bit is set, the master
will assert the SDAx line low. When the SDAx line is
sampled low, the Baud Rate Generator is reloaded and
counts down to 0. When the Baud Rate Generator
times out, the SCLx pin will be brought high and one
TBRG (Baud Rate Generator rollover count) later, the
SDAx pin will be deasserted. When the SDAx pin is
sampled high while SCLx is high, the P bit
(SSPxSTAT<4>) is set. A TBRG later, the PEN bit is
cleared and the SSPxIF bit is set (Figure 20-26).
20.5.16.1 WCOL Status Flag
If the user writes the SSPxBUF when a Stop sequence
is in progress, then the WCOL bit is set and the
contents of the buffer are unchanged (the write doesn’t
occur).
FIGURE 20-25: ACKNOWLEDGE SEQUENCE WAVEFORM
FIGURE 20-26: STOP CONDITION RECEIVE OR TRANSMIT MODE
Note: TBRG = one Baud Rate Generator period.
SDAx
SCLx
SSPxIF Set at
Acknowledge Sequence Starts Here,
Write to SSPxCON2, ACKEN Automatically Cleared
Cleared in
TBRG TBRG
the End of Receive
8
ACKEN = 1, ACKDT = 0
D0
9
SSPxIF
Software SSPxIF Set at the End
of Acknowledge Sequence
Cleared in
Software
ACK
SCLx
SDAx
SDAx is Asserted Low Before Rising Edge of Clock
Write to SSPxCON2,
Set PEN
Falling Edge of
SCLx = 1 for TBRG, Followed by SDAx = 1 for TBRG
9th Clock
SCLx Brought High After TBRG
Note: TBRG = one Baud Rate Generator period.
TBRG TBRG
After SDAx is Sampled High; P bit (SSPxSTAT<4>) is Set
TBRG
to Set up Stop Condition
ACK
P
TBRG
PEN bit (SSPxCON2<2>) is Cleared by
Hardware and the SSPxIF bit is Set
2012 Microchip Technology Inc. DS30575A-page 405
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20.5.17 SLEEP OPERATION
While in Sleep mode, the I2C module can receive
addresses or data and when an address match or
complete byte transfer occurs, wake the processor
from Sleep (if the MSSPx interrupt is enabled).
20.5.18 EFFECTS OF A RESET
A Reset disables the MSSPx module and terminates
the current transfer.
20.5.19 MULTI-MASTER MODE
In Multi-Master mode, the interrupt generation on the
detection of the Start and Stop conditions allows the
determination of when the bus is free. The Stop (P) and
Start (S) bits are cleared from a Reset or when the
MSSPx module is disabled. Control of the I2C bus may
be taken when the P bit (SSPxSTAT<4>) is set, or the
bus is Idle, with both the S and P bits clear. When the
bus is busy, enabling the MSSPx interrupt will generate
the interrupt when the Stop condition occurs.
In multi-master operation, the SDAx line must be mon-
itored for arbitration to see if the signal level is the
expected output level. This check is performed in
hardware with the result placed in the BCLxIF bit.
The states where arbitration can be lost are:
• Address Transfer
• Data Transfer
• A Start Condition
• A Repeated Start Condition
• An Acknowledge Condition
20.5.20 MULTI -MASTER COMMUNICATION,
BUS COLLISION AND BUS
ARBITRATION
Multi-Master mode support is achieved by bus arbitra-
tion. When the master outputs address/data bits onto
the SDAx pin, arbitration takes place when the master
outputs a ‘1’ on SDAx, by letting SDAx float high, and
another master asserts a ‘0’. When the SCLx pin floats
high, data should be stable. If the expected data on
SDAx is a ‘1’ and the data sampled on the SDAx
pin = 0, then a bus collision has taken place. The
master will set the Bus Collision Interrupt Flag, BCLxIF,
and reset the I2C port to its Idle state (Figure 20-27).
If a transmit was in progress when the bus collision
occurred, the transmission is halted, the BF flag is
cleared, the SDAx and SCLx lines are deasserted and
the SSPxBUF can be written to. When the user services
the bus collision Interrupt Service Routine and if the I2C
bus is free, the user can resume communication by
asserting a Start condition.
If a Start, Repeated Start, Stop or Acknowledge condi-
tion was in progress when the bus collision occurred,
the condition is aborted, the SDAx and SCLx lines are
deasserted and the respective control bits in the
SSPxCON2 register are cleared. When the user
services the bus collision Interrupt Service Routine
(ISR), and if the I2C bus is free, the user can resume
communication by asserting a Start condition.
The master will continue to monitor the SDAx and
SCLx pins. If a Stop condition occurs, the SSPxIF bit
will be set.
A write to the SSPxBUF will start the transmission of
data at the first data bit regardless of where the
transmitter left off when the bus collision occurred.
In Multi-Master mode, the interrupt generation on the
detection of Start and Stop conditions allows the determi-
nation of when the bus is free. Control of the I2C bus can
be taken when the P bit is set in the SSPxSTAT register,
or the bus is Idle and the S and P bits are cleared.
FIGURE 20-27: BUS COLLISION TIMING FOR TRANSMIT AND ACKNOWLEDGE
SDAx
SCLx
BCLxIF
SDAx Released
SDAx Line Pulled Low
by Another Source
Sample SDAx. While SCLx is High,
Data Doesn’t Match what is Driven
Bus Collision has Occurred
Set Bus Collision
Interrupt (BCLxIF)
by the Master;
by Master
Data Changes
while SCLx = 0
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DS30575A-page 406 2012 Microchip Technology Inc.
20.5.20.1 Bus Collision During a Start
Condition
During a Start condition, a bus collision occurs if:
a) SDAx or SCLx is sampled low at the beginning
of the Start condition (Figure 20-28).
b) SCLx is sampled low before SDAx is asserted
low (Figure 20-29).
During a Start condition, both the SDAx and the SCLx
pins are monitored.
If the SDAx pin is already low, or the SCLx pin is
already low, then all of the following occur:
• the Start condition is aborted,
• the BCLxIF flag is set and
• the MSSPx module is reset to its inactive state
(Figure 20-28)
The Start condition begins with the SDAx and SCLx
pins deasserted. When the SDAx pin is sampled high,
the Baud Rate Generator is loaded from
SSPxADD<6:0> and counts down to 0. If the SCLx pin
is sampled low while SDAx is high, a bus collision
occurs because it is assumed that another master is
attempting to drive a data ‘1’ during the Start condition.
If the SDAx pin is sampled low during this count, the
BRG is reset and the SDAx line is asserted early
(Figure 20-30). If, however, a ‘1’ is sampled on the
SDAx pin, the SDAx pin is asserted low at the end of
the BRG count. The Baud Rate Generator is then
reloaded and counts down to 0. If the SCLx pin is
sampled as ‘0’ during this time, a bus collision does not
occur. At the end of the BRG count, the SCLx pin is
asserted low.
FIGURE 20-28: BUS COLLISION DURING START CONDITION (SDAx ONLY)
Note: The reason that bus collision is not a fac-
tor during a Start condition is that no two
bus masters can assert a Start condition
at the exact same time. Therefore, one
master will always assert SDAx before the
other. This condition does not cause a bus
collision because the two masters must be
allowed to arbitrate the first address
following the Start condition. If the address
is the same, arbitration must be allowed to
continue into the data portion, Repeated
Start or Stop conditions.
SDAx
SCLx
SEN
SDAx Sampled Low Before
SDAx Goes Low Before the SEN bit is Set.
S bit and SSPxIF Set Because
MSSPx module Reset into Idle State
SEN Cleared Automatically Because of Bus Collision,
S bit and SSPxIF Set Because
Set SEN, Enable Start
Condition if SDAx = 1, SCLx = 1
SDAx = 0, SCLx = 1
BCLxIF
S
SSPxIF
SDAx = 0, SCLx = 1
SSPxIF and BCLxIF are
Cleared in Software
SSPxIF and BCLxIF are
Cleared in Software
Set BCLxIF,
Start Condition, Set BCLxIF,
2012 Microchip Technology Inc. DS30575A-page 407
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FIGURE 20-29: BUS COLLISION DURING START CONDITION (SCLx = 0)
FIGURE 20-30: BRG RESET DUE TO SDAx ARBITRATION DURING START CONDITION
SDAx
SCLx
SEN Bus Collision Occurs, Set BCLxIF
SCLx = 0 Before SDAx = 0,
Set SEN, Enable Start
Sequence if SDAx = 1, SCLx = 1
TBRG TBRG
SDAx = 0, SCLx = 1
BCLxIF
S
SSPxIF
Interrupt Cleared
in Software
Bus Collision Occurs, Set BCLxIF
SCLx = 0 Before BRG Time-out,
‘0’‘0’
‘0’‘0’
SDAx
SCLx
SEN
Set S
Less than TBRG TBRG
SDAx = 0, SCLx = 1
BCLxIF
S
SSPxIF
S
Interrupts Cleared
in Software
Set SSPxIF
SDAx = 0, SCLx = 1,
SCLx Pulled Low After BRG
Time-out
Set SSPxIF
‘0’
SDAx Pulled Low by Other Master,
Reset BRG and Assert SDAx
Set SEN, Enable Start
Sequence if SDAx = 1, SCLx = 1
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DS30575A-page 408 2012 Microchip Technology Inc.
20.5.20.2 Bus Collision During a Repeated
Start Condition
During a Repeated Start condition, a bus collision
occurs if:
a) A low level is sampled on SDAx when SCLx
goes from a low level to a high level.
b) SCLx goes low before SDAx is asserted low,
indicating that another master is attempting to
transmit a data ‘1’.
When the user deasserts SDAx and the pin is allowed
to float high, the BRG is loaded with SSPxADD<6:0>
and counts down to 0. The SCLx pin is then deasserted
and when sampled high, the SDAx pin is sampled.
If SDAx is low, a bus collision has occurred (i.e., another
master is attempting to transmit a data ‘0’, Figure 20-31).
If SDAx is sampled high, the BRG is reloaded and
begins counting. If SDAx goes from high-to-low before
the BRG times out, no bus collision occurs because no
two masters can assert SDAx at exactly the same time.
If SCLx goes from high-to-low before the BRG times
out and SDAx has not already been asserted, a bus
collision occurs. In this case, another master is
attempting to transmit a data ‘1’ during the Repeated
Start condition (see Figure 20-32).
If, at the end of the BRG time-out, both SCLx and SDAx
are still high, the SDAx pin is driven low and the BRG
is reloaded and begins counting. At the end of the
count, regardless of the status of the SCLx pin, the
SCLx pin is driven low and the Repeated Start
condition is complete.
FIGURE 20-31: BUS COLLISION DURING A REPEATED START CONDITION (CASE 1)
FIGURE 20-32: BUS COLLISION DURING REPEATED START CONDITION (CASE 2)
SDAx
SCLx
RSEN
BCLxIF
S
SSPxIF
Sample SDAx when SCLx goes High,
If SDAx = 0, Set BCLxIF and Release SDAx and SCLx
Cleared in Software
‘0’
‘0’
SDAx
SCLx
BCLxIF
RSEN
S
SSPxIF
Interrupt Cleared
in Software
SCLx goes Low Before SDAx,
Set BCLxIF, Release SDAx and SCLx
TBRG TBRG
‘0’
2012 Microchip Technology Inc. DS30575A-page 409
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20.5.20.3 Bus Collision During a Stop
Condition
Bus collision occurs during a Stop condition if:
a) After the SDAx pin has been deasserted and
allowed to float high, SDAx is sampled low after
the BRG has timed out.
b) After the SCLx pin is deasserted, SCLx is
sampled low before SDAx goes high.
The Stop condition begins with SDAx asserted low.
When SDAx is sampled low, the SCLx pin is allowed to
float. When the pin is sampled high (clock arbitration),
the Baud Rate Generator is loaded with
SSPxADD<6:0> and counts down to 0. After the BRG
times out, SDAx is sampled. If SDAx is sampled low, a
bus collision has occurred. This is due to another mas-
ter attempting to drive a data ‘0’ (Figure 20-33). If the
SCLx pin is sampled low before SDAx is allowed to
float high, a bus collision occurs. This is another case
of another master attempting to drive a data ‘0’
(Figure 20-34).
FIGURE 20-33: BUS COLLISION DURING A STOP CONDITION (CASE 1)
FIGURE 20-34: BUS COLLISION DURING A STOP CONDITION (CASE 2)
SDAx
SCLx
BCLxIF
PEN
P
SSPxIF
TBRG TBRG TBRG
SDAx Asserted Low
SDAx Sampled
Low After TBRG,
Set BCLxIF
‘0’
‘0’
SDAx
SCLx
BCLxIF
PEN
P
SSPxIF
TBRG TBRG TBRG
Assert SDAx SCLx goes Low Before SDAx goes High,
Set BCLxIF
‘0’
‘0’
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DS30575A-page 410 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 411
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21.0 ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)
The Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) module is one of four
serial I/O modules. (Generically, the EUSART is also
known as a Serial Communications Interface or SCI.)
The EUSART can be configured as a full-duplex,
asynchronous system that can communicate with
peripheral devices, such as CRT terminals and
personal computers. It can also be configured as a
half-duplex synchronous system that can communicate
with peripheral devices, such as A/D or D/A integrated
circuits, serial EEPROMs, etc.
The Enhanced USART module implements additional
features, including automatic baud rate detection and
calibration, automatic wake-up on Sync Break recep-
tion and 12-bit Break character transmit. These make it
ideally suited for use in Local Interconnect Network bus
(LIN/J2602 bus) systems.
All members of the PIC18F97J94 family are equipped
with four independent EUSART modules, referred to as
EUSART1, EUSART2, EUSART3 and EUSART4.
They can be configured in the following modes:
• Asynchronous (full duplex) with:
- Auto-wake-up on character reception
- Auto-baud calibration
- 12-bit Break character transmission
• Synchronous – Master (half duplex) with
selectable clock polarity
• Synchronous – Slave (half duplex) with selectable
clock polarity
The Enhanced USART module has the following
enhancements over the AUSART module:
• Selectable 16-Bit Baud Rate Generator mode
• Interrupt on Sync Break character received;
allows an asynchronous wake-up from Sleep
• 12-Bit Break character transmit
• Auto-baud calibration on Sync character
• Clock polarity select for Synchronous mode
• Transmit and receive polarity select for
Asynchronous mode
• Receive Shift register empty status bit
• Local Interconnect Network (LIN/J2602) protocol
standard
The Enhanced USART module has the following IrDA®
related enhancements over previous Enhanced
USART modules:
• 16x Baud Clock output for IrDA support
• IrDA encoder and decoder logic
The pins of EUSART1 through EUSART4 are multi-
plexed with functions using PPS-Lite. The TXx and
RXx pins of each EUSART can be individually
controlled using PPS-Lite registers, respectively.
Refer to Section 11.15 “PPS-Lite” for setting up
EUSART1 through EUSART4.
The operation of each Enhanced USART module is
controlled through seven registers:
• RCSTAx – EUSARTx Receive Status and Control
Register
• TXSTAx – EUSARTx Transmit Status and Control
Register
• BAUDCONx – Baud Rate Control Register
• SPBRGx – Baud Rate Generator Register
• SPBRGHx – Baud Rate Generator High Register
• RCREGx – EUSARTx Receive Data Register
• TXREGx – EUSARTx Transmit Data Register
These are detailed on the following pages in
Register 21-1, Register 21-2 and Register 21-3,
respectively.
Note: The EUSART control will automatically
reconfigure the pin from input to output as
needed.
Note: Throughout this section, references to
register and bit names that may be asso-
ciated with a specific EUSART module are
referred to generically by the use of ‘x’ in
place of the specific module number.
Thus, “RCSTAx” might refer to the
Receive Status register for either
EUSART1, EUSART2, EUSART3 or
EUSART4.
PIC18F97J94 FAMILY
DS30575A-page 412 2012 Microchip Technology Inc.
REGISTER 21-1: TXSTAx: EUSARTx TRANSMIT STATUS AND CONTROL REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R-1 R/W-0
CSRC TX9 TXEN(1)SYNC SENDB BRGH TRMT TX9D
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CSRC: Clock Source Select bit
Asynchronous mode:
Don’t care.
Synchronous mode:
1 = Master mode (clock generated internally from BRG)
0 = Slave mode (clock from external source)
bit 6 TX9: 9-Bit Transmit Enable bit
1 = Selects 9-bit transmission
0 = Selects 8-bit transmission
bit 5 TXEN: Transmit Enable bit(1)
1 = Transmit is enabled
0 = Transmit is disabled
bit 4 SYNC: EUSARTx Mode Select bit
1 = Synchronous mode
0 = Asynchronous mode
bit 3 SENDB: Send Break Character bit
Asynchronous mode:
1 = Send Sync Break on next transmission (cleared by hardware upon completion)
0 = Sync Break transmission has completed
Synchronous mode:
Don’t care.
bit 2 BRGH: High Baud Rate Select bit
Asynchronous mode:
1 = High speed
0 = Low speed
Synchronous mode:
Unused in this mode.
bit 1 TRMT: Transmit Shift Register Status bit
1 = TSR is empty
0 = TSR is full
bit 0 TX9D: 9th bit of Transmit Data
Can be address/data bit or a parity bit.
Note 1: SREN/CREN overrides TXEN in Sync mode.
2012 Microchip Technology Inc. DS30575A-page 413
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REGISTER 21-2: RCSTAx: EUSARTx RECEIVE STATUS AND CONTROL REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R-0 R-0 R-x
SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 SPEN: Serial Port Enable bit
1 = Serial port is enabled
0 = Serial port is disabled (held in Reset)
bit 6 RX9: 9-Bit Receive Enable bit
1 = Selects 9-bit reception
0 = Selects 8-bit reception
bit 5 SREN: Single Receive Enable bit
Asynchronous mode:
Don’t care.
Synchronous mode – Master:
1 = Enables single receive
0 = Disables single receive
This bit is cleared after reception is complete.
Synchronous mode – Slave:
Don’t care.
bit 4 CREN: Continuous Receive Enable bit
Asynchronous mode:
1 = Enables receiver
0 = Disables receiver
Synchronous mode:
1 = Enables continuous receive until enable bit, CREN, is cleared (CREN overrides SREN)
0 = Disables continuous receive
bit 3 ADDEN: Address Detect Enable bit
Asynchronous mode 9-Bit (RX9 = 1):
1 = Enables address detection, enables interrupt and loads the receive buffer when RSR<8> is set
0 = Disables address detection, all bytes are received and the ninth bit can be used as a parity bit
Asynchronous mode 9-Bit (RX9 = 0):
Don’t care.
bit 2 FERR: Framing Error bit
1 = Framing error (can be cleared by reading the RCREGx register and receiving the next valid byte)
0 = No framing error
bit 1 OERR: Overrun Error bit
1 = Overrun error (can be cleared by clearing bit, CREN)
0 = No overrun error
bit 0 RX9D: 9th bit of Received Data
This can be an address/data bit or a parity bit and must be calculated by user firmware.
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DS30575A-page 414 2012 Microchip Technology Inc.
REGISTER 21-3: BAUDCONx: BAUD RATE CONTROL REGISTER x
R/W-0 R-1 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ABDOVF RCIDL RXDTP TXCKP BRG16 IREN WUE ABDEN
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ABDOVF: Auto-Baud Acquisition Rollover Status bit
1 = A BRG rollover has occurred during Auto-Baud Rate Detect mode (must be cleared in software)
0 = No BRG rollover has occurred
bit 6 RCIDL: Receive Operation Idle Status bit
1 = Receive operation is Idle
0 = Receive operation is active
bit 5 RXDTP: Data/Receive Polarity Select bit
Asynchronous mode:
1 = Receive data (RXx) is inverted (active-low)
0 = Receive data (RXx) is not inverted (active-high)
Asynchronous IrDA mode:
No effect on operation
Synchronous mode:
1 = Data (DTx) is inverted (active-low)
0 = Data (DTx) is not inverted (active-high)
bit 4 TXCKP: Synchronous Clock Polarity Select bit
Asynchronous mode:
1 = Idle state for transmit (TXx) is a low level
0 = Idle state for transmit (TXx) is a high level
Asynchronous IrDA mode:
1 = Idle state for IrDA transmit (TX) is a high level (‘1’)
0 = Idle state for IrDA transmit (TX) is a low level (‘0’)
Synchronous mode:
1 = Idle state for clock (CKx) is a high level
0 = Idle state for clock (CKx) is a low level
bit 3 BRG16: 16-Bit Baud Rate Register Enable bit
1 = 16-bit Baud Rate Generator – SPBRGHx and SPBRGx
0 = 8-bit Baud Rate Generator – SPBRGx only (Compatible mode), SPBRGHx value is ignored
bit 2 IREN: IrDA® Encoder and Decoder Enable bit
Asynchronous mode:
1 = IrDA encoder and decoder are enabled (Asynchronous IrDA mode is active)
0 = IrDA encoder and decoder are disabled
Synchronous mode:(1)
No effect on operation.
bit 1 WUE: Wake-up Enable bit
Asynchronous mode:
1 = EUSARTx will continue to sample the RXx pin – interrupt is generated on the falling edge; bit is
cleared in hardware on following rising edge
0 = RXx pin is not monitored or rising edge detected
Synchronous mode:
Unused in this mode.
Note 1: This feature is only available in Asynchronous mode with the 16x clock preset. The 16x clock is present for
both the x16 and x64 BRG configurations.
2012 Microchip Technology Inc. DS30575A-page 415
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bit 0 ABDEN: Auto-Baud Detect Enable bit
Asynchronous mode:
1 = Enables baud rate measurement on the next character, requires reception of a Sync field (55h);
cleared in hardware upon completion
0 = Baud rate measurement is disabled or has completed
Synchronous mode:
Unused in this mode.
Note 1: This feature is only available in Asynchronous mode with the 16x clock preset. The 16x clock is present for
both the x16 and x64 BRG configurations.
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DS30575A-page 416 2012 Microchip Technology Inc.
21.1 Baud Rate Generator (BRG)
The BRG is a dedicated, 8-bit or 16-bit generator that
supports both the Asynchronous and Synchronous
modes of the EUSARTx. By default, the BRG operates
in 8-bit mode; setting the BRG16 bit (BAUDCONx<3>)
selects 16-bit mode.
The SPBRGHx:SPBRGx register pair controls the period
of a free-running timer. In Asynchronous mode, bits,
BRGH (TXSTAx<2>) and BRG16 (BAUDCONx<3>),
also control the baud rate. In Synchronous mode, BRGH
is ignored. Table 21-1 shows the formula for computation
of the baud rate for different EUSARTx modes which only
apply in Master mode (internally generated clock).
Given the desired baud rate and FOSC, the nearest
integer value for the SPBRGHx:SPBRGx registers can
be calculated using the formulas in Table 2 1- 1. From this,
the error in baud rate can be determined. An example
calculation is shown in Example 21-1. Typical baud rates
and error values for the various Asynchronous modes
are shown in Ta b l e 2 1 - 2 . It may be advantageous to use
the high baud rate (BRGH = 1) or the 16-bit BRG to
reduce the baud rate error, or achieve a slow baud rate
for a fast oscillator frequency.
Writing a new value to the SPBRGHx:SPBRGx
registers causes the BRG timer to be reset (or cleared).
This ensures the BRG does not wait for a timer over-
flow before outputting the new baud rate. When
operated in the Synchronous mode, SPBRGH:SPBRG
values of 0000h and 0001h are not supported. In the
Asynchronous mode, all BRG values may be used.
21.1.1 OPERATION IN POWER-MANAGED
MODES
The device clock is used to generate the desired baud
rate. When one of the power-managed modes is
entered, the new clock source may be operating at a
different frequency. This may require an adjustment to
the value in the SPBRGx register pair.
21.1.2 SAMPLING
The data on the RXx pin is sampled three times by a
majority detect circuit to determine if a high or a low
level is present at the RXx pin.
TABLE 21-1: BAUD RATE FORMULAS
EXAMPLE 21-1: CALCULATING BAUD RATE ERROR
Configuration Bits BRG/EUSART Mode Baud Rate Formula
SYNC BRG16 BRGH
000 8-bit/Asynchronous FOSC/[64 (n + 1)]
001 8-bit/Asynchronous FOSC/[16 (n + 1)]
010 16-bit/Asynchronous
011 16-bit/Asynchronous
FOSC/[4 (n + 1)]10x 8-bit/Synchronous
11x 16-bit/Synchronous
Legend: x = Don’t care, n = value of SPBRGHx:SPBRGx register pair
For a device with FOSC of 16 MHz, desired baud rate of 9600, Asynchronous mode, and 8-bit BRG:
Desired Baud Rate = FOSC/(64 ([SPBRGHx:SPBRGx] + 1))
Solving for SPBRGHx:SPBRGx:
X = ((FOSC/Desired Baud Rate)/64) – 1
= ((16000000/9600)/64) – 1
= [25.042] = 25
Calculated Baud Rate = 16000000/(64 (25 + 1))
= 9615
Error = (Calculated Baud Rate – Desired Baud Rate)/Desired Baud Rate
= (9615 – 9600)/9600 = 0.16%
2012 Microchip Technology Inc. DS30575A-page 417
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TABLE 21-2: BAUD RATES FOR ASYNCHRONOUS MODES
BAUD
RATE
(K)
SYNC = 0, BRGH = 0, BRG16 = 0
FOSC = 40.000 MHz FOSC = 20.000 MHz FOSC = 10.000 MHz FOSC = 8.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3————————————
1.2 — — — 1.221 1.73 255 1.202 0.16 129 1.201 -0.16 103
2.4 2.441 1.73 255 2.404 0.16 129 2.404 0.16 64 2.403 -0.16 51
9.6 9.615 0.16 64 9.766 1.73 31 9.766 1.73 15 9.615 -0.16 12
19.2 19.531 1.73 31 19.531 1.73 15 19.531 1.73 7 — — —
57.6 56.818 -1.36 10 62.500 8.51 4 52.083 -9.58 2 — — —
115.2 125.000 8.51 4 104.167 -9.58 2 78.125 -32.18 1 — — —
BAUD
RATE
(K)
SYNC = 0, BRGH = 0, BRG16 = 0
FOSC = 4.000 MHz FOSC = 2.000 MHz FOSC = 1.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3 0.300 0.16 207 0.300 -0.16 103 0.300 -0.16 51
1.2 1.202 0.16 51 1.201 -0.16 25 1.201 -0.16 12
2.4 2.404 0.16 25 2.403 -0.16 12 — — —
9.6 8.929 -6.99 6 — — — — — —
19.2 20.833 8.51 2 — — — — — —
57.6 62.500 8.51 0 — — — — — —
115.2 62.500 -45.75 0 — — — — — —
BAUD
RATE
(K)
SYNC = 0, BRGH = 1, BRG16 = 0
FOSC = 40.000 MHz FOSC = 20.000 MHz FOSC = 10.000 MHz FOSC = 8.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3————————————
1.2————————————
2.4 — — — — — — 2.441 1.73 255 2.403 -0.16 207
9.6 9.766 1.73 255 9.615 0.16 129 9.615 0.16 64 9.615 -0.16 51
19.2 19.231 0.16 129 19.231 0.16 64 19.531 1.73 31 19.230 -0.16 25
57.6 58.140 0.94 42 56.818 -1.36 21 56.818 -1.36 10 55.555 3.55 8
115.2 113.636 -1.36 21 113.636 -1.36 10 125.000 8.51 4 — — —
BAUD
RATE
(K)
SYNC = 0, BRGH = 1, BRG16 = 0
FOSC = 4.000 MHz FOSC = 2.000 MHz FOSC = 1.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3 — — — — — — 0.300 -0.16 207
1.2 1.202 0.16 207 1.201 -0.16 103 1.201 -0.16 51
2.4 2.404 0.16 103 2.403 -0.16 51 2.403 -0.16 25
9.6 9.615 0.16 25 9.615 -0.16 12 — — —
19.2 19.231 0.16 12 — — — — — —
57.6 62.500 8.51 3 — — — — — —
115.2 125.000 8.51 1 — — — — — —
PIC18F97J94 FAMILY
DS30575A-page 418 2012 Microchip Technology Inc.
BAUD
RATE
(K)
SYNC = 0, BRGH = 0, BRG16 = 1
FOSC = 40.000 MHz FOSC = 20.000 MHz FOSC = 10.000 MHz FOSC = 8.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3 0.300 0.00 8332 0.300 0.02 4165 0.300 0.02 2082 0.300 -0.04 1665
1.2 1.200 0.02 2082 1.200 -0.03 1041 1.200 -0.03 520 1.201 -0.16 415
2.4 2.402 0.06 1040 2.399 -0.03 520 2.404 0.16 259 2.403 -0.16 207
9.6 9.615 0.16 259 9.615 0.16 129 9.615 0.16 64 9.615 -0.16 51
19.2 19.231 0.16 129 19.231 0.16 64 19.531 1.73 31 19.230 -0.16 25
57.6 58.140 0.94 42 56.818 -1.36 21 56.818 -1.36 10 55.555 3.55 8
115.2 113.636 -1.36 21 113.636 -1.36 10 125.000 8.51 4 — — —
BAUD
RATE
(K)
SYNC = 0, BRGH = 0, BRG16 = 1
FOSC = 4.000 MHz FOSC = 2.000 MHz FOSC = 1.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3 0.300 0.04 832 0.300 -0.16 415 0.300 -0.16 207
1.2 1.202 0.16 207 1.201 -0.16 103 1.201 -0.16 51
2.4 2.404 0.16 103 2.403 -0.16 51 2.403 -0.16 25
9.6 9.615 0.16 25 9.615 -0.16 12 — — —
19.2 19.231 0.16 12 — — — — — —
57.6 62.500 8.51 3 — — — — — —
115.2 125.000 8.51 1 — — — — — —
BAUD
RATE
(K)
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
FOSC = 40.000 MHz FOSC = 20.000 MHz FOSC = 10.000 MHz FOSC = 8.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3 0.300 0.00 33332 0.300 0.00 16665 0.300 0.00 8332 0.300 -0.01 6665
1.2 1.200 0.00 8332 1.200 0.02 4165 1.200 0.02 2082 1.200 -0.04 1665
2.4 2.400 0.02 4165 2.400 0.02 2082 2.402 0.06 1040 2.400 -0.04 832
9.6 9.606 0.06 1040 9.596 -0.03 520 9.615 0.16 259 9.615 -0.16 207
19.2 19.193 -0.03 520 19.231 0.16 259 19.231 0.16 129 19.230 -0.16 103
57.6 57.803 0.35 172 57.471 -0.22 86 58.140 0.94 42 57.142 0.79 34
115.2 114.943 -0.22 86 116.279 0.94 42 113.636 -1.36 21 117.647 -2.12 16
BAUD
RATE
(K)
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
FOSC = 4.000 MHz FOSC = 2.000 MHz FOSC = 1.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
0.3 0.300 0.01 3332 0.300 -0.04 1665 0.300 -0.04 832
1.2 1.200 0.04 832 1.201 -0.16 415 1.201 -0.16 207
2.4 2.404 0.16 415 2.403 -0.16 207 2.403 -0.16 103
9.6 9.615 0.16 103 9.615 -0.16 51 9.615 -0.16 25
19.2 19.231 0.16 51 19.230 -0.16 25 19.230 -0.16 12
57.6 58.824 2.12 16 55.555 3.55 8 — — —
115.2 111.111 -3.55 8 — — — — — —
TABLE 21-2: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
2012 Microchip Technology Inc. DS30575A-page 419
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21.1.3 AUTO-BAUD RATE DETECT
The Enhanced USART module supports the automatic
detection and calibration of baud rate. This feature is
active only in Asynchronous mode and while the WUE
bit is clear.
The automatic baud rate measurement sequence
(Figure 21-1) begins whenever a Start bit is received
and the ABDEN bit is set. The calculation is
self-averaging.
In the Auto-Baud Rate Detect (ABD) mode, the clock to
the BRG is reversed. Rather than the BRG clocking the
incoming RXx signal, the RXx signal is timing the BRG.
In ABD mode, the internal Baud Rate Generator is
used as a counter to time the bit period of the incoming
serial byte stream.
Once the ABDEN bit is set, the state machine will clear
the BRG and look for a Start bit. The Auto-Baud Rate
Detect must receive a byte with the value, 55h (ASCII
“U”, which is also the LIN/J2602 bus Sync character), in
order to calculate the proper bit rate. The measurement
is taken over both a low and a high bit time in order to
minimize any effects caused by asymmetry of the incom-
ing signal. After a Start bit, the SPBRGx begins counting
up, using the preselected clock source on the first rising
edge of RXx. After eight bits on the RXx pin or the fifth
rising edge, an accumulated value totalling the proper
BRG period is left in the SPBRGHx:SPBRGx register
pair. Once the 5th edge is seen (this should correspond
to the Stop bit), the ABDEN bit is automatically cleared.
If a rollover of the BRG occurs (an overflow from FFFFh
to 0000h), the event is trapped by the ABDOVF status
bit (BAUDCONx<7>). It is set in hardware by BRG roll-
overs and can be set or cleared by the user in software.
ABD mode remains active after rollover events and the
ABDEN bit remains set (Figure 21-2).
While calibrating the baud rate period, the BRG regis-
ters are clocked at 1/8th the preconfigured clock rate.
The BRG clock will be configured by the BRG16 and
BRGH bits. The BRG16 bit must be set to use both
SPBRG1 and SPBRGH1 as a 16-bit counter. This
allows the user to verify that no carry occurred for 8-bit
modes by checking for 00h in the SPBRGHx register.
Refer to Table 21-3 for counter clock rates to the BRG.
While the ABD sequence takes place, the EUSARTx
state machine is held in Idle. The RCxIF interrupt is set
once the fifth rising edge on RXx is detected. The value
in the RCREGx needs to be read to clear the RCxIF
interrupt. The contents of RCREGx should be
discarded.
TABLE 21-3: BRG COUNTER
CLOCK RATES
21.1.3.1 ABD and EUSARTx Transmission
Since the BRG clock is reversed during ABD acquisi-
tion, the EUSARTx transmitter cannot be used during
ABD. This means that whenever the ABDEN bit is set,
TXREGx cannot be written to. Users should also
ensure that ABDEN does not become set during a
transmit sequence. Failing to do this may result in
unpredictable EUSARTx operation.
Note 1: If the WUE bit is set with the ABDEN bit,
Auto-Baud Rate Detection will occur on
the byte following the Break character.
2: It is up to the user to determine that the
incoming character baud rate is within the
range of the selected BRG clock source.
Some combinations of oscillator
frequency and EUSARTx baud rates are
not possible due to bit error rates. Overall
system timing and communication baud
rates must be taken into consideration
when using the Auto-Baud Rate Detection
feature.
3: To maximize baud rate range, if that
feature is used it is recommended that
the BRG16 bit (BAUDCONx<3>) be set.
BRG16 BRGH BRG Counter Clock
00 FOSC/512
01 FOSC/128
10 FOSC/128
11 FOSC/32
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DS30575A-page 420 2012 Microchip Technology Inc.
FIGURE 21-1: AUTOMATIC BAUD RATE CALCULATION
FIGURE 21-2: BRG OVERFLOW SEQUENCE
BRG Value
RXx Pin
ABDEN bit
RCxIF bit
Bit 0 Bit 1
(Interrupt)
Read
RCREGx
BRG Clock
Start
Auto-Cleared
Set by User
XXXXh 0000h
Edge #1
Bit 2 Bit 3
Edge #2
Bit 4 Bit 5
Edge #3
Bit 6 Bit 7
Edge #4
001Ch
Note: The ABD sequence requires the EUSARTx module to be configured in Asynchronous mode and WUE = 0.
SPBRGx XXXXh 1Ch
SPBRGHx XXXXh 00h
Edge #5
Stop Bit
Start Bit 0
XXXXh 0000h 0000h
FFFFh
BRG Clock
ABDEN bit
RXx Pin
ABDOVF bit
BRG Value
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21.2 EUSARTx Asynchronous Mode
The Asynchronous mode of operation is selected by
clearing the SYNC bit (TXSTAx<4>). In this mode, the
EUSARTx uses standard Non-Return-to-Zero (NRZ)
format (one Start bit, eight or nine data bits and one Stop
bit). The most common data format is 8 bits. An on-chip,
dedicated 8-bit/16-bit Baud Rate Generator can be used
to derive standard baud rate frequencies from the
oscillator.
The EUSARTx transmits and receives the LSb first. The
EUSARTx’s transmitter and receiver are functionally
independent but use the same data format and baud
rate. The Baud Rate Generator produces a clock, either
x16 or x64 of the bit shift rate, depending on the BRGH
and BRG16 bits (TXSTAx<2> and BAUDCONx<3>).
Parity is not supported by the hardware but can be
implemented in software and stored as the 9th data bit.
When operating in Asynchronous mode, the EUSARTx
module consists of the following important elements:
• Baud Rate Generator
• Sampling Circuit
• Asynchronous Transmitter
• Asynchronous Receiver
• Auto-Wake-up on Sync Break Character
• 12-Bit Break Character Transmit
• Auto-Baud Rate Detection
21.2.1 EUSARTx ASYNCHRONOUS
TRANSMITTER
The EUSARTx transmitter block diagram is shown in
Figure 21-3. The heart of the transmitter is the Transmit
(Serial) Shift Register (TSR). The Shift register obtains
its data from the Read/Write Transmit Buffer register,
TXREGx. The TXREGx register is loaded with data in
software. The TSR register is not loaded until the Stop
bit has been transmitted from the previous load. As
soon as the Stop bit is transmitted, the TSR is loaded
with new data from the TXREGx register (if available).
Once the TXREGx register transfers the data to the TSR
register (occurs in one T
CY), the TXREGx register is
empty and the TXxIF flag bit is set. This interrupt can be
enabled or disabled by setting or clearing the interrupt
enable bit, TXxIE. TXxIF will be set regardless of the
state of TXxIE; it cannot be cleared in software. TXxIF is
also not cleared immediately upon loading TXREGx, but
becomes valid in the second instruction cycle following
the load instruction. Polling TXxIF immediately following
a load of TXREGx will return invalid results.
While TXxIF indicates the status of the TXREGx regis-
ter, another bit, TRMT (TXSTAx<1>), shows the status
of the TSR register. TRMT is a read-only bit which is set
when the TSR register is empty. No interrupt logic is
tied to this bit so the user has to poll this bit in order to
determine if the TSR register is empty.
To set up an Asynchronous Transmission:
1. Initialize the SPBRGHx:SPBRGx registers for
the appropriate baud rate. Set or clear the
BRGH and BRG16 bits, as required, to achieve
the desired baud rate.
2. Enable the asynchronous serial port by clearing
bit, SYNC, and setting bit, SPEN.
3. If interrupts are desired, set enable bit, TXxIE.
4. If 9-bit transmission is desired, set transmit bit,
TX9. Can be used as address/data bit.
5. Enable the transmission by setting bit, TXEN,
which will also set bit, TXxIF.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit, TX9D.
7. Load data to the TXREGx register (starts
transmission).
8. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
FIGURE 21-3: EUSARTx TRANSMIT BLOCK DIAGRAM
Note 1: The TSR register is not mapped in data
memory, so it is not available to the user.
2: Flag bit, TXxIF, is set when enable bit,
TXEN, is set.
TXxIF
TXxIE
Interrupt
TXEN Baud Rate CLK
SPBRGx
Baud Rate Generator TX9D
MSb LSb
Data Bus
TXREGx Register
TSR Register
(8) 0
TX9
TRMT SPEN
TXx Pin
Pin Buffer
and Control
8
SPBRGHx
BRG16
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FIGURE 21-4: ASYNCHRONOUS TRANSMISSION
FIGURE 21-5: ASYNCHRONOUS TRANSMISSION (BACK-TO-BACK)
Word 1
Word 1
Transmit Shift Reg
Start bit bit 0 bit 1 bit 7/8
Write to TXREGx
BRG Output
(Shift Clock)
TXx (pin)
TXxIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
1 TCY
Stop bit
Word 1
Transmit Shift Reg.
Write to TXREGx
BRG Output
(Shift Clock)
TXx (pin)
TXxIF bit
(Interrupt Reg. Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Word 1 Word 2
Word 1 Word 2
Stop bit Start bit
Transmit Shift Reg.
Word 1 Word 2
bit 0 bit 1 bit 7/8 bit 0
Note: This timing diagram shows two consecutive transmissions.
1 TCY
1 TCY
Start bit
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21.2.2 EUSARTx ASYNCHRONOUS
RECEIVER
The receiver block diagram is shown in Figure 21-6.
The data is received on the RXx pin and drives the data
recovery block. The data recovery block is actually a
high-speed shifter operating at x16 times the baud rate,
whereas the main receive serial shifter operates at the
bit rate or at FOSC. This mode would typically be used
in RS-232 systems.
To set up an Asynchronous Reception:
1. Initialize the SPBRGHx:SPBRGx registers for
the appropriate baud rate. Set or clear the
BRGH and BRG16 bits, as required, to achieve
the desired baud rate.
2. Enable the asynchronous serial port by clearing
bit, SYNC, and setting bit, SPEN.
3. If interrupts are desired, set enable bit, RCxIE.
4. If 9-bit reception is desired, set bit, RX9.
5. Enable the reception by setting bit, CREN.
6. Flag bit, RCxIF, will be set when reception is
complete and an interrupt will be generated if
enable bit, RCxIE, was set.
7. Read the RCSTAx register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
8. Read the 8-bit received data by reading the
RCREGx register.
9. If any error occurred, clear the error by clearing
enable bit, CREN.
10. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
21.2.3 SETTING UP 9-BIT MODE WITH
ADDRESS DETECT
This mode would typically be used in RS-485 systems.
To set up an Asynchronous Reception with Address
Detect Enable:
1. Initialize the SPBRGHx:SPBRGx registers for
the appropriate baud rate. Set or clear the
BRGH and BRG16 bits, as required, to achieve
the desired baud rate.
2. Enable the asynchronous serial port by clearing
the SYNC bit and setting the SPEN bit.
3. If interrupts are required, set the RCEN bit and
select the desired priority level with the RCxIP bit.
4. Set the RX9 bit to enable 9-bit reception.
5. Set the ADDEN bit to enable address detect.
6. Enable reception by setting the CREN bit.
7. The RCxIF bit will be set when reception is
complete. The interrupt will be Acknowledged if
the RCxIE and GIE bits are set.
8. Read the RCSTAx register to determine if any
error occurred during reception, as well as read
bit 9 of data (if applicable).
9. Read RCREGx to determine if the device is
being addressed.
10. If any error occurred, clear the CREN bit.
11. If the device has been addressed, clear the
ADDEN bit to allow all received data into the
receive buffer and interrupt the CPU.
FIGURE 21-6: EUSARTx RECEIVE BLOCK DIAGRAM
x64 Baud Rate CLK
Baud Rate Generator
RXx
Pin Buffer
and Control
SPEN
Data
Recovery
CREN OERR FERR
RSR Register
MSb LSb
RX9D RCREGx Register
FIFO
Interrupt RCxIF
RCxIE
Data Bus
8
64
16
or
Stop Start
(8) 7 1 0
RX9
SPBRGxSPBRGHx
BRG16
or
4
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FIGURE 21-7: ASYNCHRONOUS RECEPTION
21.2.4 AUTO-WAKE-UP ON SYNC BREAK
CHARACTER
During Sleep mode, all clocks to the EUSARTx are
suspended. Because of this, the Baud Rate Generator
is inactive and a proper byte reception cannot be per-
formed. The auto-wake-up feature allows the controller
to wake-up due to activity on the RXx/DTx line while the
EUSARTx is operating in Asynchronous mode.
The auto-wake-up feature is enabled by setting the
WUE bit (BAUDCONx<1>). Once set, the typical
receive sequence on RXx/DTx is disabled and the
EUSARTx remains in an Idle state, monitoring for a
wake-up event independent of the CPU mode. A
wake-up event consists of a high-to-low transition on
the RXx/DTx line. (This coincides with the start of a
Sync Break or a Wake-up Signal character for the
LIN/J2602 protocol.)
Following a wake-up event, the module generates an
RCxIF interrupt. The interrupt is generated synchro-
nously to the Q clocks in normal operating modes
(Figure 21-8) and asynchronously if the device is in
Sleep mode (Figure 21-9). The interrupt condition is
cleared by reading the RCREGx register.
The WUE bit is automatically cleared once a low-to-high
transition is observed on the RXx line following the
wake-up event. At this point, the EUSARTx module is in
Idle mode and returns to normal operation. This signals
to the user that the Sync Break event is over.
21.2.4.1 Special Considerations Using
Auto-Wake-up
Since auto-wake-up functions by sensing rising edge
transitions on RXx/DTx, information with any state
changes before the Stop bit may signal a false
End-of-Character (EOC) and cause data or framing
errors. To work properly, therefore, the initial character
in the transmission must be all ‘0’s. This can be 00h
(8 bits) for standard RS-232 devices or 000h (12 bits)
for the LIN/J2602 bus.
Oscillator start-up time must also be considered,
especially in applications using oscillators with longer
start-up intervals (i.e., HS or HSPLL mode). The Sync
Break (or Wake-up Signal) character must be of
sufficient length and be followed by a sufficient interval
to allow enough time for the selected oscillator to start
and provide proper initialization of the EUSARTx.
Start
bit bit 7/8
bit 1bit 0 bit 7/8 bit 0
Stop
bit
Start
bit
Start
bit
bit 7/8 Stop
bit
RXx (pin)
Rcv Buffer Reg
Rcv Shift Reg
Read Rcv
Buffer Reg
RCREGx
RCxIF
(Interrupt Flag)
OERR bit
CREN
Word 1
RCREGx
Word 2
RCREGx
Stop
bit
Note: This timing diagram shows three words appearing on the RXx input. The RCREGx (Receive Buffer) is read after the third word,
causing the OERR (Overrun) bit to be set.
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21.2.4.2 Special Considerations Using
the WUE Bit
The timing of WUE and RCxIF events may cause some
confusion when it comes to determining the validity of
received data. As noted, setting the WUE bit places the
EUSARTx in an Idle mode. The wake-up event causes
a receive interrupt by setting the RCxIF bit. The WUE bit
is cleared after this when a rising edge is seen on
RXx/DTx. The interrupt condition is then cleared by
reading the RCREGx register. Ordinarily, the data in
RCREGx will be dummy data and should be discarded.
The fact that the WUE bit has been cleared (or is still
set), and the RCxIF flag is set, should not be used as
an indicator of the integrity of the data in RCREGx.
Users should consider implementing a parallel method
in firmware to verify received data integrity.
To assure that no actual data is lost, check the RCIDL
bit to verify that a receive operation is not in process. If
a receive operation is not occurring, the WUE bit may
then be set just prior to entering the Sleep mode.
FIGURE 21-8: AUTO-WAKE-UP BIT (WUE) TIMINGS DURING NORMAL OPERATION
FIGURE 21-9: AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
WUE bit(1)
RXx/DTx Line
RCxIF
Note 1: The EUSARTx remains in Idle while the WUE bit is set.
Bit Set by User
Cleared due to User Read of RCREGx
Auto-Cleared
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
WUE bit(2)
RXx/DTx Line
RCxIF
Cleared due to User Read of RCREGx
SLEEP Command Executed
Note 1: If the wake-up event requires long oscillator warm-up time, the auto-clear of the WUE bit can occur before the oscillator is ready. This
sequence should not depend on the presence of Q clocks.
2: The EUSARTx remains in Idle while the WUE bit is set.
Sleep Ends
Note 1
Auto-Cleared
Bit Set by User
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21.2.5 BREAK CHARACTER SEQUENCE
The EUSARTx module has the capability of sending
the special Break character sequences that are
required by the LIN/J2602 bus standard. The Break
character transmit consists of a Start bit, followed by
twelve ‘0’ bits and a Stop bit. The Frame Break charac-
ter is sent whenever the SENDB and TXEN bits
(TXSTAx<3> and TXSTAx<5>, respectively) are set
while the Transmit Shift Register is loaded with data.
Note that the value of data written to TXREGx will be
ignored and all ‘0’s will be transmitted.
The SENDB bit is automatically reset by hardware after
the corresponding Stop bit is sent. This allows the user
to preload the transmit FIFO with the next transmit byte
following the Break character (typically, the Sync
character in the LIN/J2602 specification).
Note that the data value written to the TXREGx for the
Break character is ignored. The write simply serves the
purpose of initiating the proper sequence.
The TRMT bit indicates when the transmit operation is
active or Idle, just as it does during normal transmis-
sion. See Figure 21-10 for the timing of the Break
character sequence.
21.2.5.1 Break and Sync Transmit Sequence
The following sequence will send a message frame
header made up of a Break, followed by an Auto-Baud
Sync byte. This sequence is typical of a LIN/J2602 bus
master.
1. Configure the EUSARTx for the desired mode.
2. Set the TXEN and SENDB bits to set up the
Break character.
3. Load the TXREGx with a dummy character to
initiate transmission (the value is ignored).
4. Write ‘55h’ to TXREGx to load the Sync
character into the transmit FIFO buffer.
5. After the Break has been sent, the SENDB bit is
reset by hardware. The Sync character now
transmits in the preconfigured mode.
When the TXREGx becomes empty, as indicated by
the TXxIF, the next data byte can be written to
TXREGx.
21.2.6 RECEIVING A BREAK CHARACTER
The Enhanced USART module can receive a Break
character in two ways.
The first method forces configuration of the baud rate
at a frequency of 9/13 the typical speed. This allows for
the Stop bit transition to be at the correct sampling
location (13 bits for Break versus Start bit and 8 data
bits for typical data).
The second method uses the auto-wake-up feature
described in Section 21.2.4 “Auto-Wake-up on Sync
Break Character”. By enabling this feature, the
EUSARTx will sample the next two transitions on
RXx/DTx, cause an RCxIF interrupt and receive the
next data byte followed by another interrupt.
Note that following a Break character, the user will
typically want to enable the Auto-Baud Rate Detect
feature. For both methods, the user can set the ABDEN
bit once the TXxIF interrupt is observed.
FIGURE 21-10: SEND BREAK CHARACTER SEQUENCE
Write to TXREGx
BRG Output
(Shift Clock)
Start Bit Bit 0 Bit 1 Bit 11 Stop Bit
Break
TXxIF bit
(Transmit Buffer
Reg. Empty Flag)
TXx (pin)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
SENDB bit
(Transmit Shift
Reg. Empty Flag)
SENDB sampled here Auto-Cleared
Dummy Write
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21.3 EUSARTx Synchronous
Master Mode
The Synchronous Master mode is entered by setting
the CSRC bit (TXSTAx<7>). In this mode, the data is
transmitted in a half-duplex manner (i.e., transmission
and reception do not occur at the same time). When
transmitting data, the reception is inhibited and vice
versa. Synchronous mode is entered by setting bit,
SYNC (TXSTAx<4>). In addition, enable bit, SPEN
(RCSTAx<7>), is set in order to configure the TXx and
RXx pins to CKx (clock) and DTx (data) lines,
respectively.
The Master mode indicates that the processor trans-
mits the master clock on the CKx line. Clock polarity is
selected with the TXCKP bit (BAUDCONx<4>). Setting
TXCKP sets the Idle state on CKx as high, while clear-
ing the bit sets the Idle state as low. This option is
provided to support Microwire devices with this module.
21.3.1 EUSARTx SYNCHRONOUS
MASTER TRANSMISSION
The EUSARTx transmitter block diagram is shown in
Figure 21-3. The heart of the transmitter is the Transmit
(Serial) Shift Register (TSR). The shift register obtains
its data from the Read/Write Transmit Buffer register,
TXREGx. The TXREGx register is loaded with data in
software. The TSR register is not loaded until the last
bit has been transmitted from the previous load. As
soon as the last bit is transmitted, the TSR is loaded
with new data from the TXREGx (if available).
Once the TXREGx register transfers the data to the
TSR register (occurs in one TCY), the TXREGx is empty
and the TXxIF flag bit is set. The interrupt can be
enabled or disabled by setting or clearing the interrupt
enable bit, TXxIE. TXxIF is set regardless of the state
of enable bit, TXxIE; it cannot be cleared in software. It
will reset only when new data is loaded into the
TXREGx register.
While flag bit, TXxIF, indicates the status of the TXREGx
register, another bit, TRMT (TXSTAx<1>), shows the
status of the TSR register. TRMT is a read-only bit which
is set when the TSR is empty. No interrupt logic is tied to
this bit, so the user must poll this bit in order to determine
if the TSR register is empty. The TSR is not mapped in
data memory so it is not available to the user.
To set up a Synchronous Master Transmission:
1. Initialize the SPBRGHx:SPBRGx registers for the
appropriate baud rate. Set or clear the BRG16
bit, as required, to achieve the desired baud rate.
2. Enable the Master Synchronous Serial Port by
setting bits, SYNC, SPEN and CSRC.
3. If interrupts are desired, set enable bit, TXxIE.
4. If 9-bit transmission is desired, set bit, TX9.
5. Enable the transmission by setting bit, TXEN.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit, TX9D.
7. Start transmission by loading data to the
TXREGx register.
8. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
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FIGURE 21-11: SYNCHRONOUS TRANSMISSION
FIGURE 21-12: SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
bit 0 bit 1 bit 7
Word 1
Q1 Q2 Q3Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
bit 2 bit 0 bit 1 bit 7
TX1/CK1 Pin
Write to
TxREG1 Reg
Tx1IF bit
(Interrupt Flag)
TXEN bit ‘1’ ‘1’
Word 2
TRMT bit
Write Word 1 Write Word 2
Note: Sync Master mode, SPBRGx = 0, continuous transmission of two 8-bit words. This example is equally applicable to EUSART2 (TX2/CK2
and RX2/DT2).
RX1/DT1 Pin
(TXCKP = 0)
TX1/CK1 Pin
(TXCKP = 1)
RX1/DT1 Pin
TX1/CK1 Pin
Write to
TXREG1 reg
TX1IF bit
TRMT bit
bit 0 bit 1 bit 2 bit 6 bit 7
TXEN bit
Note: This example is equally applicable to EUSART2 (TX2/CK2 and RX2/DT2).
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21.3.2 EUSARTx SYNCHRONOUS
MASTER RECEPTION
Once Synchronous mode is selected, reception is
enabled by setting either the Single Receive Enable bit,
SREN (RCSTAx<5>) or the Continuous Receive
Enable bit, CREN (RCSTAx<4>). Data is sampled on
the RXx pin on the falling edge of the clock.
If enable bit, SREN, is set, only a single word is
received. If enable bit, CREN, is set, the reception is
continuous until CREN is cleared. If both bits are set,
then CREN takes precedence.
To set up a Synchronous Master Reception:
1. Initialize the SPBRGHx:SPBRGx registers for the
appropriate baud rate. Set or clear the BRG16
bit, as required, to achieve the desired baud rate.
2. Enable the Master Synchronous Serial Port by
setting bits, SYNC, SPEN and CSRC.
3. Ensure bits, CREN and SREN, are clear.
4. If interrupts are desired, set enable bit, RCxIE.
5. If 9-bit reception is desired, set bit, RX9.
6. If a single reception is required, set bit, SREN.
For continuous reception, set bit, CREN.
7. Interrupt flag bit, RCxIF, will be set when recep-
tion is complete and an interrupt will be generated
if the enable bit, RCxIE, was set.
8. Read the RCSTAx register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
9. Read the 8-bit received data by reading the
RCREGx register.
10. If any error occurred, clear the error by clearing
bit CREN.
11. If using interrupts, ensure that the GIE and PEIE bits
in the INTCON register (INTCON<7:6>) are set.
FIGURE 21-13: SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
CREN bit
Write to bit,
SREN
SREN bit
RC1IF bit
(Interrupt)
Read
RCREG1
Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Q2 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
‘
0
’
bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7
‘
0
’
Q1 Q2 Q3 Q4
Note: Timing diagram demonstrates Sync Master mode with bit, SREN = 1, and bit, BRGH = 0. This example is equally applicable to EUSART2
(TX2/CK2 and RX2/DT2).
RX1/DT1 Pin
TX1/CK1 Pin
(TXCKP = 0)
TX1/CK1 Pin
(TXCKP = 1)
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21.4 EUSARTx Synchronous
Slave Mode
Synchronous Slave mode is entered by clearing bit,
CSRC (TXSTAx<7>). This mode differs from the
Synchronous Master mode in that the shift clock is sup-
plied externally at the CKx pin (instead of being supplied
internally in Master mode). This allows the device to
transfer or receive data while in any low-power mode.
21.4.1 EUSARTx SYNCHRONOUS
SLAVE TRANSMISSION
The operation of the Synchronous Master and Slave
modes is identical, except in the case of Sleep mode.
If two words are written to the TXREGx and then the
SLEEP instruction is executed, the following will occur:
a) The first word will immediately transfer to the
TSR register and transmit.
b) The second word will remain in the TXREGx
register.
c) Flag bit, TXxIF, will not be set.
d) When the first word has been shifted out of TSR,
the TXREGx register will transfer the second word
to the TSR and flag bit, TXxIF, will now be set.
e) If enable bit, TXxIE, is set, the interrupt will wake
the chip from Sleep. If the global interrupt is
enabled, the program will branch to the interrupt
vector.
To set up a Synchronous Slave Transmission:
1. Enable the synchronous slave serial port by
setting bits, SYNC and SPEN, and clearing bit,
CSRC.
2. Clear bits, CREN and SREN.
3. If interrupts are desired, set enable bit, TXxIE.
4. If 9-bit transmission is desired, set bit, TX9.
5. Enable the transmission by setting enable bit,
TXEN.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit, TX9D.
7. Start transmission by loading data to the
TXREGx register.
8. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
21.4.2 EUSARTx SYNCHRONOUS SLAVE
RECEPTION
The operation of the Synchronous Master and Slave
modes is identical, except in the case of Sleep, or any
Idle mode and bit, SREN, which is a “don’t care” in
Slave mode.
If receive is enabled by setting the CREN bit prior to
entering Sleep or any Idle mode, then a word may be
received while in this Low-Power mode. Once the word
is received, the RSR register will transfer the data to the
RCREGx register. If the RCxIE enable bit is set, the
interrupt generated will wake the chip from the
Low-Power mode. If the global interrupt is enabled, the
program will branch to the interrupt vector.
To set up a Synchronous Slave Reception:
1. Enable the Master Synchronous Serial Port by
setting bits, SYNC and SPEN, and clearing bit,
CSRC.
2. If interrupts are desired, set enable bit, RCxIE.
3. If 9-bit reception is desired, set bit, RX9.
4. To enable reception, set enable bit, CREN.
5. Flag bit, RCxIF, will be set when reception is
complete. An interrupt will be generated if
enable bit, RCxIE, was set.
6. Read the RCSTAx register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
7. Read the 8-bit received data by reading the
RCREGx register.
8. If any error occurred, clear the error by clearing
bit, CREN.
9. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
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21.5 Infrared Support
This module provides support for two types of infrared
USART port implementations:
• IrDA clock output to support an external IrDA
encoder/decoder device
• Full implementation of the IrDa encoder and
decoder as part of the USART logic
Since the 16x clock is required to perform the IrDA
encoding, both by this module and the external trans-
mitter, this feature only works in the 16x Baud Rate
mode and is not available in the 4x mode.
21.5.1 EXTERNAL IrDA SUPPORT – IRDA
CLOCK OUTPUT
The 16x Baud Clock is provided on the BCLK (Baud
Clock) pin if the EUSARTx is enabled (SPEN = 1); it is
configured for Asynchronous mode (SYNC = 0) when
Clock Source Select is active (CSRC = 1). Note that
the BCLK can be active in regular or IrDA mode (IREN
bit is ignored).
21.5.1.1 BCLK Output
The timing of the Baud Clock (BCLK) output is inde-
pendent of the 16x or 4x Baud Rate mode, resulting in
the same output for a particular BRG value (since the
4x mode is four times faster, but has four times less
pulses per period).
When the BCLK pin mode is active, the RXx Baud
Rate Generator will be turned on, independent of a
TXx or RXx operation. This will cause the RXx stream
to synchronize to the already running RXx Baud Clock.
This is acceptable only when BCLK is enabled for use.
The BCLK output goes inactive and stays low during
Sleep mode.
The BCLK pin is taken over by the EUSARTx module
and forced as an output, irrespective of port latch and
TRIS latch bits. BCLK remains an output as long as
USART is kept enabled in this mode.
FIGURE 21-14: BCLK OUTPUT vs. BRG PROGRAMMING
(BRG + 1)
[INT(BRG + 1)/2]
16x or 4x Clock
BCLK @ BRG = 0
BCLK @ BRG = 1
BCLK @ BRG = 2
BCLK @ BRG = 3
BCLK @ BRG = 4
BCLK @ BRG = 5
BCLK @ BRG = n
Note: The BCLK has 50% duty cycle only for odd BRG values. This is due to having all BCLK edges synchronous to the
rising edge of the 16x/4x clock.
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21.5.2 BUILT-IN IrDA ENCODER AND
DECODER
The built-in IrDA encoder and decoder functionality is
enabled using the IREN bit in the BAUDCONx register
while the module is in Asynchronous mode
(SYNC = 0). When enabled (IREN = 1), the Receive
pin (RXx) acts as the input from the infrared receiver.
The Transmit pin (TXx) acts as the output to the infra-
red transmitter. The 16x clock must be available for
this feature to work properly.
The IrDA feature cannot be enabled for Synchronous
modes (SYNC = 1).
21.5.2.1 IrDA Encoder Function
The encoder works by taking the serial data from the
USART and replacing it as follows:
• Transmit bit data of ‘1’ gets encoded as ‘0’ for the
entire 16 periods of the 16x Baud Clock
• Transmit bit data of ‘0’ gets encoded as ‘0’ for the
first 7 periods of the 16x Baud Clock, then as ‘1’
for the next 3 periods, and as ‘0’ for the remaining
6 periods
See Figure 21-15 and Figure 21-17 for details.
21.5.2.2 IrDA Transmit Polarity
The IrDA transmit polarity is selected using the
TXCKP bit. This bit only affects the transmit encoder
and does not affect the receiver.
When TXCKP = 0, the Idle state of the TXx line is ‘0’
(see Figure 21-15). When TXCKP = 1, the Idle state of
the TXx line is ‘1’ (see Figure 21-16).
FIGURE 21-15: IrDA® ENCODING SCHEME
FIGURE 21-16: INVERTED IrDA® ENCODING (TXCKP = 1)
FIGURE 21-17: ‘0’ BIT DATA IrDA® ENCODING SCHEME
TXx Data
TXx (tx_out)
TXx Data
TXx (tx_out)
Start ofStart of
‘0’ Transmit bit
16x Baud Clock
TXx Data
TXx (tx_out)
8th Period 11th Period
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21.5.2.3 IrDA Decoder Function
The decoder works by taking the serial data from the
RXx pin and replacing it with the decoded data stream.
The stream is decoded based on falling edge
detection of the RXx input.
Each falling edge of RXx causes the decoded data to
be driven low for 16 periods of the 16x Baud Clock. If
another falling edge has been detected by the time the
16 periods expire, the decoded data remains low for
another 16 periods. If no falling edge was detected,
the decoded data is driven high.
Note that the data stream into the device is shifted
anywhere from 7 to 8 periods of the 16x Baud Clock
from the actual message source. The one clock uncer-
tainty is due to the clock edge resolution. See
Figure 21-18 for details.
21.5.2.4 IrDA Receive Polarity
The IrDA receive polarity is selected using the RXDTP
bit. This bit only affects the receive encoder and does
not affect the transmitter.
When RXDTP = 0, the Idle state of the RXx line is ‘1’
(see Figure 21-18). When RXDTP = 1, the Idle state of
the RXx line is ‘0’ (see Figure 21-19).
21.5.2.5 Clock Jitter
Due to jitter or slight frequency differences between
devices, it is possible for the next falling bit edge to be
missed for one of the 16x periods. In that case, one
clock-wide pulse appears on the decoded data stream.
Since the EUSARTx performs a majority detect around
the bit center, this does not cause erroneous data. See
Figure 21-20 for details.
FIGURE 21-18: MACRO VIEW OF IrDA® DECODING SCHEME (RXDTP = 0)
FIGURE 21-19: INVERTED POLARITY DECODING RESULTS (RXDTP = 1)
FIGURE 21-20: CLOCK JITTER CAUSING A PULSE BETWEEN CONSECUTIVE ZEROS
16 Periods 16 Periods 16 Periods 16 Periods 16 Periods
Start BRG TIRDEL
Before IrDA Encoder
RXx (rx_in)
Decoded Data
(Transmitting device)
16 Periods 16 Periods 16 Periods 16 Periods 16 Periods
Start BRG TIRDEL
Before IrDA Encoder
RXx (rx_in)
Decoded Data
(Transmitting device)
16 Periods 16 Periods
Extra pulse will be ignored
RXx (rx_in)
Decoded Data
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NOTES:
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22.0 12-BIT A/D CONVERTER WITH
THRESHOLD SCAN
The 12-bit A/D Converter has the following key
features:
• Successive Approximation Register (SAR)
Conversion
• Conversion Speeds of up to 200 ksps at 12 bits
and 500 ksps at 10 bits
• Up to 32 Analog Input Channels (internal and
external)
• Selectable 10-Bit or 12-Bit (default) Conversion
• Resolution
• Multiple Internal Reference Input Channels
• External Voltage Reference Input Pins
• Unipolar Differential Sample-and-Hold (S/H)
Amplifier
• Automated Threshold Scan and Compare Opera-
tion to Pre-Evaluate up to 26 Conversion Results
• Selectable Conversion Trigger Source
• Fixed Length (one word per channel),
Configurable Conversion Result Buffer
• Four Options for Results Alignment
• Configurable Interrupt Generation
• Operation During CPU Sleep and Idle modes
The 12-bit A/D Converter module is an enhanced
version of the 10-bit module offered in some PIC18
devices. Both modules are Successive Approximation
Register (SAR) Converters at their cores, surrounded
by a range of hardware features for flexible configura-
tion. This version of the module extends functionality by
providing 12-bit resolution, a wider range of automatic
sampling options, tighter integration with other analog
modules, such as the CTMU, and a configurable
results buffer. This module also includes a unique
Threshold Detect feature that allows the module itself
to make simple decisions based on the conversion
results.
As before, an internal Sample-and-Hold (S/H) amplifier
acquires a sample of an input signal, then holds that
value constant during the conversion process. A com-
bination of input multiplexers selects the signal to be
converted from up to 32 analog inputs, both external
(analog input pins) and internal (e.g., on-chip voltage
references and other analog modules). The whole mul-
tiplexer path includes provisions for differential analog
input, although, with a limited number of negative input
pins. The sampled voltage is held and converted to a
digital value, which strictly speaking, represents the
ratio of that input voltage to a reference voltage.
Configuration choices allow connection of an external
reference or use of the device power and ground (AVDD
and AVSS). Reference and input signal pins are
assigned differently depending on the particular device.
An array of timing and control selections allow the user
to create flexible scanning sequences. Conversions
can be started individually by program control, continu-
ously free-running or triggered by selected hardware
events. A single channel may be repeatedly converted.
Alternate conversions may be performed on two chan-
nels, or any or all of the channels may be sequentially
scanned and converted according to a user-defined bit
map. The resulting conversion output is a 12-bit digital
number, which can be signed or unsigned, left or right
justified. (In some devices, a user-selectable resolution
of 10 bits is available; in other devices, 12-bit resolution
is the only option available.)
Conversions are automatically stored in a dedicated
buffer, allowing for multiple successive readings to be
taken before software service is needed. The buffer
can be configured to function as a FIFO buffer or as a
channel indexed buffer. In FIFO mode, the buffer can
be split into two equal sections for simultaneous con-
version and read operations. In Indexed mode, the buf-
fer can use the Threshold Scan feature to determine if
a conversion meets specific, user-defined criteria, stor-
ing or discarding the converted value as appropriate,
and then set semaphore flags to indicate the event.
This allows conversions to occur in low-power modes
when the CPU is inactive, waking the device only when
specific conditions have occurred.
The module sets its interrupt flag after a selectable
number of conversions, when the buffer can be read, or
after a successful Threshold Detect comparison. After
the interrupt, the sequence restarts at the beginning of
the buffer. When the interrupt flag is set, according to
the earlier selection, scan selections and the Output
Buffer Pointer return to their starting positions.
During Sleep or Idle mode, the A/D can wake-up at pre-
configured intervals while the device maintains a
Low-Power mode. If threshold conditions have not
been met on any of the conversions, the module will
return to a Low-Power mode.
The A/D module provides configuration to directly inter-
act with the CTMU on specific input channels. This
allows the CTMU to automatically turn on only when
requested directly by the A/D, even though the rest of
the device stays in Sleep mode.
A simplified block diagram for the module is shown in
Figure 22-1.
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FIGURE 22-1: 12-BIT A/D CONVERTER BLOCK DIAGRAM (PIC18F97J94 FAMILY)
Note 1: AN16 through AN23 are implemented on 80-pin and 100-pin devices only.
Comparator
12-Bit SAR Conversion Logic
VREF+
DAC
AN(n-1)
ANn(1)
AN8
AN9
AN4
AN5
AN6
AN7
AN0
AN1
AN2
AN3
VREF-
Sample Control
S/H
AVSS
AVDD
ADC1BUF0:
ADC1BUFn(3)
AD1CON1
AD1CON2
AD1CON3
AD1CHS
AD1CHITL
AD1CHITH
Control Logic
Data Formatting
Input MUX Control
Conversion Control
Pin Config. Control
Internal Data Bus
16
VR+VR-
MUX A
MUX B
VINH
VINL
VINH
VINH
VINL
VINL
VR+
VR-
VR Select
VBG(2)
VBG/6(2)
AD1CSSL
CTMU(2)
V
DDCORE
(2)
AVSS(2)
AVDD(2)
AD1CON5
VBG/2(2)
VBG
AD1CSSH
AD1CTMENL
AD1CTMENH
AD1DMBUF
AD1CON4
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22.1 Registers
The 12-bit A/D converter module uses up to 75
registers for its operation. All registers are mapped in
the data memory space.
22.1.1 CONTROL REGISTERS
Depending on the specific device, the module has up to
twelve control and status registers:
• ADCON1H/L: A/D Control Registers
• ADCON2H/L: A/D Control Registers
• ADCON3H/L: A/D Control Registers
• ADCON5H/L: A/D Control Registers
• ADCHS0H/L: A/D Input Channel Select Registers
• ADCHITH1H/L and ADCHITH0H/L: A/D Scan
Compare Hit Registers
• ADCSS1H/L and ADCSS0H/L: A/D Input Scan
Select Registers
• ADCTMUEN1H/L and ADCTMUEN0H/L: CTMU
Enable Register
The ADCON1H/L, ADCON2H/L and ADCON3H/L reg-
isters control the overall operation of the A/D module.
This includes enabling the module, configuring the con-
version clock and voltage reference sources, selecting
the sampling and conversion triggers, and manually
controlling the sample/convert sequences. The
ADCON5H/L registers specifically controls features of
Threshold Detect operation, including its functioning in
power-saving modes.
The ADCHS0H/L registers selects the input channels
to be connected to the S/H amplifier. It also allows the
choice of input multiplexers and the selection of a
reference source for differential sampling.
The ADCHITH1H/L and ADCHITH0H/L registers are
semaphore registers used with Threshold Detect
operations. The status of individual bits, or bit pairs in
some cases, indicate if a match condition has occurred.
Their use is described in more detail in Section 22.7
“Threshold Detect Operation”. ADCHITH0H/L is
always implemented, whereas ADCHITH1H/L may not
be implemented in devices with 16 channels or less.
The ADCSS0H/L/L registers select the channels to be
included for sequential scanning. The
ADCTMUEN1H/L/L registers select the channel(s) to
be used by the CTMU during conversions. Selecting a
particular channel allows the A/D Converter to control
the CTMU (particularly, its current source) and read its
data through that channel. ADCTMUEN0H/L is always
implemented, whereas ADCTMUEN1H/L may not be
implemented in devices with 16 channels or less.
22.1.2 A/D RESULT BUFFERS
The module incorporates a multi-word, dual port RAM,
called ADCBUF. The buffer is composed of at least the
same number of word locations as there are external
analog channels for a particular device, with a
maximum number of 26. The number of buffer
addresses is always even. Each of the locations is
mapped into the data memory space and is separately
addressable.The buffer locations are referred to as
ADCBUF0H/L through ADCBUFnH/L (up to 26).
The A/D result buffers are both readable and writable.
When the module is active (ADCON1H<7> = 1), the
buffers are read-only, and store the results of A/D
conversions. When the module is inactive
(ADCON1H<7> = 0), the buffers are both readable and
writable. In this state, writing to a buffer location
programs a conversion threshold for Threshold Detect
operations, as described in Section 22.7.2 “Setting
Comparison Thresholds”.
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REGISTER 22-1: ANCON1: ANALOG SELECT CONTROL REGISTER 1 (FOR AN7-AN0)
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
ANSEL7 ANSEL6 ANSEL5 ANSEL4 ANSEL3 ANSEL2 ANSEL1 ANSEL0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ANSEL7: Pin RG0 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 6 ANSEL6: Pin RF2 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 5 ANSEL5: Pin RA5 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 4 ANSEL4: Pin RA4 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 3 ANSEL3: Pin RA3 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 2 ANSEL2: Pin RA2 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 1 ANSEL1: Pin RA1 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 0 ANSEL0: Pin RA0 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
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REGISTER 22-2: ANCON2: ANALOG SELECT CONTROL REGISTER 2 (FOR AN15-AN8)
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
ANSEL15 ANSEL14 ANSEL13 ANSEL12 ANSEL11 ANSEL10 ANSEL9 ANSEL8
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ANSEL15: Pin RG4 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 6 ANSEL14: Pin RG3 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 5 ANSEL13: Pin RG2 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 4 ANSEL12: Pin RG1 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 3 ANSEL11: Pin RF7 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 2 ANSEL10: Pin RF6 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 1 ANSEL9: Pin RF5 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
bit 0 ANSEL8: Pin RC2 Analog Enable bit
1 = Pin configured as an analog channel – digital input is disabled and reads ‘0’
0 = Pin configured as a digital port
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REGISTER 22-3: ANCON3: ANALOG SELECT CONTROL REGISTER 3 (FOR AN23-AN16)
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
ANSEL23 ANSEL22 ANSEL21 ANSEL20 ANSEL19 ANSEL18 ANSEL17 ANSEL16
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ANSEL23: Pin RH7 Analog Enable
1 = Pin configured as an analog channel – digital input disabled and reads ‘0’
0 = Pin configured as a digital port
bit 6 ANSEL22: Pin RH6 Analog Enable
1 = Pin configured as an analog channel – digital input disabled and reads ‘0’
0 = Pin configured as a digital port
bit 5 ANSEL21: Pin RH5 Analog Enable
1 = Pin configured as an analog channel – digital input disabled and reads ‘0’
0 = Pin configured as a digital port
bit 4 ANSEL20: Pin RH4 Analog Enable
1 = Pin configured as an analog channel – digital input disabled and reads ‘0’
0 = Pin configured as a digital port
bit 3 ANSEL19: Pin RH3 Analog Enable
1 = Pin configured as an analog channel – digital input disabled and reads ‘0’
0 = Pin configured as a digital port
bit 2 ANSEL18: Pin RH2 Analog Enable
1 = Pin configured as an analog channel – digital input disabled and reads ‘0’
0 = Pin configured as a digital port
bit 1 ANSEL17: Pin RH1 Analog Enable
1 = Pin configured as an analog channel – digital input disabled and reads ‘0’
0 = Pin configured as a digital port
bit 0 ANSEL16: Pin RH0 Analog Enable
1 = Pin configured as an analog channel – digital input disabled and reads ‘0’
0 = Pin configured as a digital port
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REGISTER 22-4: ADCON1H: A/D CONTROL REGISTER 1 HIGH
R/W-0 U-0 U-0 U-0 U-0 R/W-0 R/W-0 R/W-0
ADON — — — —MODE12FORM1FORM0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ADON: A/D Operating Mode bit
1 = A/D Converter module is operating
0 = A/D Converter is off
bit 6-3 Unimplemented: Read as ‘0’
bit 2 MODE12: 12-Bit Operation Mode bit
1 = 12-bit A/D operation
0 = 10-bit A/D operation
bit 1-0 FORM<1:0>: Data Output Format bits (see following formats)
11 = Fractional result, signed, left-justified
10 = Absolute fractional result, unsigned, left-justified
01 = Decimal result, signed, right-justified
00 = Absolute decimal result, unsigned, right-justified
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REGISTER 22-5: ADCON1L: A/D CONTROL REGISTER 1 LOW
R/W-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0 R/W-0, HSC R/C-0, HSC
SSRC3 SSRC2 SSRC1 SSRC0 — ASAM SAMP DONE
bit 7 bit 0
Legend: C = Clearable bit U = Unimplemented bit, read as ‘0’
R = Readable bit W = Writable bit HSC = Hardware Settable/Clearable bit
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 SSRC<3:0>: Sample Clock Source Select bits
1xxx = Unimplemented, do not use
0111 = The SAMP bit is cleared after SAMC<4:0> number of T
AD clocks following the SAMP bit being
set (Auto-Convert mode); no extended sample time is present
0110 = Unimplemented
0101 =TMR1
0100 =CTMU
0011 =TMR5
0010 =TMR3
0001 =INT0
0000 = The SAMP bit must be cleared by software to start conversion
bit 3 Unimplemented: Read as ‘0’
bit 2 ASAM: A/D Sample Auto-Start bit
1 = Sampling begins immediately after last conversion; SAMP bit is auto-set
0 = Sampling begins when SAMP bit is manually set
bit 1 SAMP: A/D Sample Enable bit
1 = A/D Sample-and-Hold amplifiers are sampling
0 = A/D Sample-and-Hold amplifiers are holding
bit 0 DONE: A/D Conversion Status bit
1 = A/D conversion cycle has completed
0 = A/D conversion has not started or is in progress
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REGISTER 22-6: ADCON2H: A/D CONTROL REGISTER 2 HIGH
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 U-0
PVCFG1 PVCFG0 NVCFG0 OFFCAL BUFREGEN CSCNA — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 PVCFG<1:0>: Converter Positive Voltage Reference Configuration bits
1x = Unimplemented, do not use
01 =External V
REF+
00 =AV
DD
bit 5 NVCFG0: Converter Negative Voltage Reference Configuration bit
1 =External VREF-
0 =AV
SS
bit 4 OFFCAL: Offset Calibration Mode Select bit
1 = Inverting and non-inverting inputs of channel Sample-and-Hold are connected to AVSS
0 = Inverting and non-inverting inputs of channel Sample-and-Hold are connected to normal inputs
bit 3 BUFREGEN: A/D Buffer Register Enable bit
1 = Conversion result is loaded into the buffer location determined by the converted channel
0 = A/D result buffer is treated as a FIFO
bit 2 CSCNA: Scan Input Selections for CH0+ During Sample A bit
1 =Scans inputs
0 = Does not scan inputs
bit 1-0 Unimplemented: Read as ‘0’
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REGISTER 22-7: ADCON2L: A/D CONTROL REGISTER 2 LOW
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
BUFS(1)SMPI4 SMPI3 SMPI2 SMPI1 SMPI0 BUFM(1)ALTS
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 BUFS: Buffer Fill Status bit(1)
1 = A/D is filling the upper half of the buffer; user should access data in the lower half
0 = A/D is filling the lower half of the buffer; user should access data in the upper half
bit 6-2 SMPI<4:0>: Interrupt Sample Increment Rate Select bits
Selects the number of sample/conversions per each interrupt.
11111 = Interrupt/address increment at the completion of conversion for each 32nd sample
11110 = Interrupt/address increment at the completion of conversion for each 31st sample
00001 = Interrupt/address increment at the completion of conversion for every other sample
00000 = Interrupt/address increment at the completion of conversion for each sample
bit 1 BUFM: Buffer Fill Mode Select bit(1)
1 = A/D buffer is two, 13-word buffers, starting at ADC1BUF0 and ADC1BUF12, and sequential
conversions fill the buffers alternately (Split mode)
0 = A/D buffer is a single, 26-word buffer and fills sequentially from ADC1BUF0 (FIFO mode)
bit 0 ALTS: Alternate Input Sample Mode Select bit
1 = Uses channel input selects for Sample A on first sample and Sample B on next sample
0 = Always uses channel input selects for Sample A
Note 1: These bits are only applicable when the buffer is used in FIFO mode (BUFREGEN = 0). In addition, BUFS
is only used when BUFM = 1.
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REGISTER 22-8: ADCON3H: A/D CONTROL REGISTER 3 HIGH
R/W-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ADRC EXTSAM PUMPEN SAMC4 SAMC3 SAMC2 SAMC1 SAMC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ADRC: A/D Conversion Clock Source bit
1 = RC Clock
0 = Clock derived from system clock
bit 6 EXTSAM: Extended Sampling Time bit
1 = A/D is still sampling after SAMP = 0
0 = A/D is finished sampling
bit 5 PUMPEN: Charge Pump Enable bit
1 = Charge pump for switches is enabled
0 = Charge pump for switches is disabled
bit 4-0 SAMC<4:0>: Auto-Sample Time Select bits
11111 = 31 T
AD
00001 =1 T
AD
00000 = 0 TAD
REGISTER 22-9: ADCON3L: A/D CONTROL REGISTER 3 LOW
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ADCS7 ADCS6 ADCS5 ADCS4 ADCS3 ADCS2 ADCS1 ADCS0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 ADCS<7:0>: A/D Conversion Clock Select bits ((ADCS<7:0> + 1) T
CY) = TAD
11111111
= Reserved
01000000
00111111 = 64·TCY =TAD
00000001 = 2·T
CY =TAD
00000000 = TCY =TAD
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REGISTER 22-10: ADCON5H: A/D CONTROL REGISTER 5 HIGH
R/W-0 R/W-0 R/W-0 U-0 U-0 U-0 R/W-0 R/W-0
ASENA LPENA CTMUREQ — — — ASINTMD1 ASINTMD0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 ASENA: Auto-Scan Enable bit
1 = Auto-scan is enabled
0 = Auto-scan is disabled
bit 6 LPENA: Low-Power Enable bit
1 = Low power is enabled after scan
0 = Full power is enabled after scan
bit 5 CTMUREQ: CTMU Request bit
1 = CTMU is enabled when the A/D is enabled and active
0 = CTMU is not enabled by the A/D
bit 4-2 Unimplemented: Read as ‘0’
bit 1-0 ASINTMD<1:0>: Auto-Scan (Threshold Detect) Interrupt Mode bits
11 = Interrupt after Threshold Detect sequence completed and valid compare has occurred
10 = Interrupt after valid compare has occurred
01 = Interrupt after Threshold Detect sequence completed
00 = No interrupt
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REGISTER 22-11: ADCON5L: A/D CONTROL REGISTER 5 LOW
U-0 U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0
———— WM1 WM0 CM1 CM0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 Unimplemented: Read as ‘0’
bit 3-2 WM<1:0>: Write Mode bits
11 = Reserved
10 = Auto-compare only (conversion results are not saved, but interrupts are generated when a valid
match occurs, as defined by the CM<1:0> and ASINTMD<1:0> bits)
01 = Convert and save (conversion results are saved to locations as determined by the register bits
when a match occurs, as defined by the CMx bits)
00 = Legacy operation (conversion data is saved to a location determined by the buffer register bits)
bit 1-0 CM<1:0>: Compare Mode bits
11
= Outside Window mode (valid match occurs if the conversion result is outside of the window, defined
by the corresponding buffer pair)
10
= Inside Window mode (valid match occurs if the conversion result is inside the window, defined by the
corresponding buffer pair)
01
= Greater Than mode (valid match occurs if the result is greater than the value in the corresponding
buffer register)
00
= Less Than mode (valid match occurs if the result is less than the value in the corresponding buffer
register)
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REGISTER 22-12: ADCHS0H: A/D SAMPLE SELECT REGISTER 0 HIGH
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CH0NB2 CH0NB1 CH0NB0 CH0SB4 CH0SB3 CH0SB2 CH0SB1 CH0SB0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 CH0NB<2:0>: Sample B Channel 0 Negative Input Select bits
1xx = Unimplemented
011 = Unimplemented
010 =AN1
001 = Unimplemented
000 =V
REF-/AVSS
bit 4-0 CH0SB<4:0>: Sample B Channel 0 Positive Input Select bits
11111 =V
BAT/2(1)
11110 =AVDD(1)
11101 =AVSS(1)
11100 = Band gap reference (VBG)(1)
11011 =VBG/2(1)
11010 =VBG/6(1)
11001 =CTMU
11000 = CTMU temperature sensor input (does not require ADCTMUEN1H<0> to be set)
10111 =AN23
(2)
10110 =AN22
(2)
10101 =AN21
(2)
10100 =AN20
(2)
10011 =AN19
(2)
10010 =AN18
(2)
10001 =AN17
(2)
10000 =AN16
(2)
01111 =AN15
01110 =AN14
01101 =AN13
01100 =AN12
01011 =AN11
01010 =AN10
01001 =AN9
01000 =AN8
00111 =AN7
00110 =AN6
00101 =AN5
00100 =AN4
00011 =AN3
00010 =AN2
00001 =AN1
00000 =AN0
Note 1: These input channels do not have corresponding memory mapped result buffers.
2: These channels are implemented in 80-pin and 100-pin devices only.
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REGISTER 22-13: ADCHS0L: A/D SAMPLE SELECT REGISTER 0 LOW
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CH0NA2 CH0NA1 CH0NA0 CH0SA4 CH0SA3 CH0SA2 CH0SA1 CH0SA0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 CH0NA<2:0>: Sample A Channel 0 Negative Input Select bits
1xx = Unimplemented
011 = Unimplemented
010 =AN1
001 = Unimplemented
000 =V
REF-/AVSS
bit 4-0 CH0SA<4:0>: Sample A Channel 0 Positive Input Select bits
11111 =V
BAT/2(1)
11110 =AVDD(1)
11101 =AVSS(1)
11100 = Band gap reference (VBG)(1)
11011 =VBG/2(1)
11010 =VBG/6(1)
11001 =CTMU
11000 = CTMU temperature sensor input (does not require ADCTMUEN1H<0> to be set)
10111 =AN23
(2)
10110 =AN22
(2)
10101 =AN21
(2)
10100 =AN20
(2)
10011 =AN19
(2)
10010 =AN18
(2)
10001 =AN17
(2)
10000 =AN16
(2)
01111 =AN15
01110 =AN14
01101 =AN13
01100 =AN12
01011 =AN11
01010 =AN10
01001 =AN9
01000 =AN8
00111 =AN7
00110 =AN6
00101 =AN5
00100 =AN4
00011 =AN3
00010 =AN2
00001 =AN1
00000 =AN0
Note 1: These input channels do not have corresponding memory mapped result buffers.
2: These channels are implemented in 80-pin and 100-pin devices only.
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REGISTER 22-14: ADHIT1H: A/D SCAN COMPARE HIT REGISTER 1 HIGH (HIGH WORD)
U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— CHH30 CHH29 CHH28 CHH27 CHH26 CHH25 CHH24
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-0 CHH<30:24>: A/D Compare Hit bits
If CM<1:0> = 11:
1 = A/D Result Buffer n has been written with data or a match has occurred
0 = A/D Result Buffer n has not been written with data
For All Other Values of CM<1:0>:
1 = A match has occurred on A/D Result Channel n
0 = No match has occurred on A/D Result Channel n
REGISTER 22-15: ADHIT1L: A/D SCAN COMPARE HIT REGISTER 1 LOW (LOW WORD)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CHH23 CHH22 CHH21 CHH20 CHH19 CHH18 CHH17 CHH16
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CHH<23:16>: A/D Compare Hit bits
If CM<1:0> = 11:
1 = A/D Result Buffer n has been written with data or a match has occurred
0 = A/D Result Buffer n has not been written with data
For All Other Values of CM<1:0>:
1 = A match has occurred on A/D Result Channel n
0 = No match has occurred on A/D Result Channel n
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REGISTER 22-16: ADHIT0H: A/D SCAN COMPARE HIT REGISTER 0 HIGH (HIGH WORD)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CHH15 CHH14 CHH13 CHH12 CHH11 CHH10 CHH9 CHH8
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CHH<15:8>: A/D Compare Hit bits
If CM<1:0> = 11:
1 = A/D Result Buffer n has been written with data or a match has occurred
0 = A/D Result Buffer n has not been written with data
For all other values of CM<1:0>:
1 = A match has occurred on A/D Result Channel n
0 = No match has occurred on A/D Result Channel n
REGISTER 22-17: ADHIT0L: A/D SCAN COMPARE HIT REGISTER 0 LOW (LOW WORD)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CHH7 CHH6 CHH5 CHH4 CHH3 CHH2 CHH1 CHH0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CHH<7:0>: A/D Compare Hit bits
If CM<1:0> = 11:
1 = A/D Result Buffer n has been written with data or a match has occurred
0 = A/D Result Buffer n has not been written with data
For all other values of CM<1:0>:
1 = A match has occurred on A/D Result Channel n
0 = No match has occurred on A/D Result Channel n
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REGISTER 22-18: ADCSS1H: A/D INPUT SCAN SELECT REGISTER 1 HIGH (HIGH WORD)
U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— CSS30 CSS29 CSS28 CSS27 CSS26 CSS25 CSS24
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-0 CSS<30:24>: A/D Input Scan Selection bits
1 = Includes corresponding channel for input scan
0 = Skips channel for input scan
REGISTER 22-19: ADCSS1L: A/D INPUT SCAN SELECT REGISTER 1 LOW (LOW WORD)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CSS23 CSS22 CSS21 CSS20 CSS19 CSS18 CSS17 CSS16
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 15-0 CSS<23:16>: A/D Input Scan Selection bits
1 = Includes corresponding channel for input scan
0 = Skips channel for input scan
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REGISTER 22-20: ADCSS0H: A/D INPUT SCAN SELECT REGISTER 0 HIGH (HIGH WORD)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CSS15 CSS14 CSS13 CSS12 CSS11 CSS10 CSS9 CSS8
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CSS<15:8>: A/D Input Scan Selection bits
1 = Includes corresponding channel for input scan
0 = Skips channel for input scan
REGISTER 22-21: ADCSS0L: A/D INPUT SCAN SELECT REGISTER 0 LOW (LOW WORD)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CSS7 CSS6 CSS5 CSS4 CSS3 CSS2 CSS1 CSS0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CSS<7:0>: A/D Input Scan Selection bits
1 = Includes corresponding channel for input scan
0 = Skips channel for input scan
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REGISTER 22-22: ADCTMUEN1H: CTMU ENABLE REGISTER 1 HIGH (HIGH WORD)(1)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— CTMUEN30 CTMUEN29 CTMUEN28 CTMUEN27 CTMUEN26 CTMUEN25 CTMUEN24
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-0 CTMUEN<30:24>: CTMU Enabled During Conversion bits
1 = CTMU is enabled and connected to the selected channel during conversion
0 = CTMU is not connected to this channel
Note 1: The actual number of channels available depends on which channels are implemented on a specific
device; refer to the device data sheet for details. Unimplemented channels are read as ‘0’.
REGISTER 22-23: ADCTMUEN1L: CTMU ENABLE REGISTER 1 LOW (LOW WORD)(1)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CTMUEN23 CTMUEN22 CTMUEN21 CTMUEN20 CTMUEN19 CTMUEN18 CTMUEN17 CTMUEN16
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 15-0 CTMUEN<23:16>: CTMU Enabled During Conversion bits
1 = CTMU is enabled and connected to the selected channel during conversion
0 = CTMU is not connected to this channel
Note 1: The actual number of channels available depends on which channels are implemented on a specific
device; refer to the device data sheet for details. Unimplemented channels are read as ‘0’.
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REGISTER 22-24: ADCTMUEN0H: CTMU ENABLE REGISTER 0 HIGH (HIGH WORD)(1)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CTMUEN15 CTMUEN14 CTMUEN13 CTMUEN12 CTMUEN11 CTMUEN10 CTMUEN9 CTMUEN8
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CTMUEN<15:8>: CTMU Enabled During Conversion bits
1 = CTMU is enabled and connected to the selected channel during conversion
0 = CTMU is not connected to this channel
Note 1: The actual number of channels available depends on which channels are implemented on a specific
device; refer to the device data sheet for details. Unimplemented channels are read as ‘0’.
REGISTER 22-25: ADCTMUEN0L: CTMU ENABLE REGISTER 0 LOW (LOW WORD)(1)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CTMUEN7 CTMUEN6 CTMUEN5 CTMUEN4 CTMUEN3 CTMUEN2 CTMUEN1 CTMUEN0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 CTMUEN<7:0>: CTMU Enabled During Conversion bits
1 = CTMU is enabled and connected to the selected channel during conversion
0 = CTMU is not connected to this channel
Note 1: The actual number of channels available depends on which channels are implemented on a specific
device; refer to the device data sheet for details. Unimplemented channels are read as ‘0’.
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22.2 A/D Terminology and Conversion
Sequence
Sample time is the time that the A/D module's S/H
amplifier is connected to the analog input pin. The sam-
ple time may be started and ended automatically by the
A/D Converter's hardware or under direct program con-
trol. There is a minimum sample time to ensure that the
S/H amplifier will give sufficient accuracy for the A/D
conversion.
The conversion trigger ends the sampling time and
begins an A/D conversion or a repeating sequence.
The conversion trigger sources can be taken from a
variety of hardware sources or can be controlled
directly in software. One of the conversion trigger
options is an auto-conversion, which uses a counter
and the A/D clock to set the time between auto-conver-
sions. The Auto-Sample mode and auto-conversion
trigger can be used together to provide continuous,
automatic conversions without software intervention.
When automatic sampling is used, an extended sam-
pling interval is extended between the time the sam-
pling ends and the conversion starts.
Conversion time is the time required for the A/D
Converter to convert the voltage held by the S/H ampli-
fier. An A/D conversion requires one A/D clock cycle
(TAD) to convert each bit of the result, plus two addi-
tional clock cycles, or a total of 14 TAD cycles for a
12-bit conversion. When the conversion is complete,
the result is loaded into one of the A/D result buffers.
The S/H can be reconnected to the input pin and a CPU
interrupt may be generated. The sum of the sample
time(s) and the A/D conversion time provides the total
A/D sequence time. Figure 22-2 shows the basic
conversion sequence and the relationship between
intervals.
FIGURE 22-2: A/D SAMPLE/CONVERT SEQUENCE
Sample Time A/D Conversion Time
Total A/D Sequence Time
S/H amplifier is connected to
the analog input pin for sampling.
Input disconnected; S/H amplifier holds signal.
Conversion trigger starts A/D conversion.
Conversion complete, result is loaded
into A/D Buffer register.
Interrupt is generated (optional).
Extended Sampling Time(1)
Sampling ends (manual or
automatic trigger).
Total A/D Sample Time
Note 1: In Automatic Sampling modes, Extended Sampling Time is added to the sequence when the value for the
Auto-Sampling Time is greater than 0. Otherwise, sampling ends and conversion starts whenever the SAMP bit is
cleared.
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22.2.1 OPERATION AS A STATE MACHINE
The A/D conversion process can be thought of in terms
of a finite state machine (Figure 22-3). The sample
state represents the time that the input channel is
connected to the S/H amplifier and the signal is passed
to the converter input. The convert state is transitory.
The module enters this state as soon as it exits the
sample state and transitions to a different state when
that is done. The inactive state is the default state prior
to module initialization and following a software-con-
trolled conversion; it can be avoided in operation by
using Auto-Sample mode. Machine states are identi-
fied by the state of several control and status bits in
ADCON1H/L.
If the module is configured for Auto-Sample mode, the
operation “ping-pongs” continuously between the
sample and convert states. The module automatically
selects the input channels to be sampled (if channel
scanning is enabled), while the selected conversion
trigger source paces the entire operation. Any time that
Auto-Sample mode is not used for conversion, it is
available for the sample state. The user needs to make
certain that acquisition time is sufficient, in addition to
accounting for the normal concerns about system
throughput.
Whenever the issue of sampling time is important, the
significant event is the transition from sample to con-
vert state. This is the point where the Sample-and-Hold
aperture closes, and it is essentially the signal value at
this instant, which is applied to the A/D for conversion
to digital.
FIGURE 22-3: A/D MODULE STATE MACHINE MODEL
INACTIVE
SAMPLE CONVERT
SAMP = 0
DONE = 1
SAMP = 0
DONE =
0
SAMP = 1
DONE = x
SAMP 0→1
ASAM = 1 and DONE 0→1
ASAM = 0 and
SSRCx Trigger Events
DONE 0→1
Device Reset
Legend: HW = Automatic Hardware event; SW = Software Controlled event.
Note: See Register 22-5 for definitions of the ASAM, SAMP, DONE and SSRC<3:0> bits.
SW
HW
HW
ASAM 0→1 or
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22.3 A/D Module Configuration
All of the registers described in the previous section
must be configured for module operation to be fully
defined. An effective approach is first, to describe the
signals and sequences for the particular application.
Typically, it is an iterative process to assign signals to
port pins, to establish timing methods and to organize
a scanning scheme, as well as to integrate the whole
process with the software design.
The various configuration and control functions of the
module are distributed throughout the module's six
control registers. Control functions can be broadly
sorted into four groups: input, timing, conversion and
output. Table 22-1 shows the register location of control
or status bits by register.
TABLE 22-1: A/D MODULE FUNCTIONS BY REGISTERS AND BITS
The following steps should be followed for performing
an A/D conversion:
1. Configure the A/D module:
- Select the output resolution (if configurable)
- Select the voltage reference source to match
the expected range on analog inputs
- Select the analog conversion clock to match
the desired data rate with a processor clock
- Determine how sampling will occur
- Set the multiplexer input assignments
- Select the desired sample/conversion
sequence
- Select the output data format
- Select the output value destination
- Select the number of readings per interrupt
2. Configure the A/D interrupt (if required):
- Clear the ADIF bit
- Select the A/D interrupt priority
3. Turn on the A/D module.
The options for each configuration step are described
in the subsequent sections.
22.3.1 SELECTING THE RESOLUTION
The MODE12 bit (ADCON1H<3>) controls output
resolution. Setting this bit selects 12-bit resolution.
22.3.2 SELECTING THE VOLTAGE
REFERENCE SOURCE
The voltage references for A/D conversions are
selected using the PVCFG<1:0> and NVCFG0 control
bits (ADCON2H<7:5>). The upper voltage reference
(VR+) may be AVDD, the external VREF+ or an internal
band gap reference voltage. The lower voltage
reference (VR-) may be AVSS or the VREF- input pin.
The available options vary between device families.
The external voltage reference pins may be shared
with the AN0 and AN1 inputs on low pin count devices.
The A/D Converter can still perform conversions on
these pins when they are shared with the VREF+ and
VREF- input pins.
The voltages applied to the external reference pins
must meet certain specifications. Refer to the device
data sheet for further details.
A/D Function Register(s) Specific Bits
Input AD1CON2 PVCFG<1:0>, NVCFG, OFFCAL, CSCNA, ALTS
AD1CON5 CTMREQ, BGREQ, VRSREQ
AD1CHS CH0NB<2:0>, CH0SB<4:0>, CH0NA<2:0>, CH0SA<4:0>
AD1CSSH/L CSS<31:16>, CSS<15:0>(1)
AD1CTMENH/L CTMEN<31:16>, CTMEN<15:0>(1)
Conversion AD1CON1 ADON, ADSIDL, SSRC<3:0>, ASAM, SAMP, DONE
AD1CON2 SMPI<4:0>
AD1CON3 EXTSAM
AD1CON5 ASEN, LPEN, ASINT<1:0>
Timing AD1CON3 ADRC, SAMC<4:0>, ADCS<7:0>
Output AD1CON1 FORM<1:0>, DMAEN, DMABM
AD1CON2 BUFS, BUFM, BUFREGEN
AD1CON4 DMABL<2:0>
AD1CON5 WM<1:0>, CM<1:0>
Note: Do not write to the SSRCx, BUFS, SMPIx,
BUFM and ALTS bits, or the AD1CON3
and AD1CSSL registers, while ADON = 1;
otherwise, indeterminate conversion data
may result.
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22.3.3 SELECTING THE A/D CONVERSION
CLOCK
The A/D Converter has a maximum rate at which
conversions may be completed. An analog module
clock, TAD, controls the conversion timing. The A/D
conversion requires 14 clock periods (14 TAD) for a
12-bit conversion and 12 clock periods (12 TAD) for a
10-bit conversion. The A/D clock is derived from the
device instruction clock.
The period of the A/D conversion clock is software
selected using a 6-bit counter. There are 64 possible
options for TAD, specified by the ADCSX bits in the
ADCON3L register. Equation 22-1 gives the TAD value
as a function of the ADCSx control bits and the device
instruction cycle clock period, TCY. For correct A/D
conversions, the A/D conversion clock (TAD) must be
selected to ensure a minimum TAD time, as specified
by the device family data sheet.
EQUATION 22-1: A/D CONVERSION CLOCK
PERIOD
The A/D Converter also has its own dedicated RC clock
source that can be used to perform conversions. The
A/D RC clock source should be used when conversions
are performed while the device is in Sleep mode. The
RC oscillator is selected by setting the ADRC bit
(ADCON3H<7>). When the ADRC bit is set, the
ADCSx bits have no effect on A/D operation.
22.3.4 CONFIGURING ANALOG PORT
PINS
The A/D module does not have an internal provision to
configure port pins for analog operation. Instead, input
pins are configured as analog inputs through the
Analog Select registers (ANSn, where ‘n’ is the port
name). A pin is configured as an analog input when the
corresponding ANSn bit is set. By default, pins with
multiplexed analog and digital functions are configured
as analog pins on device Reset.
For external analog inputs, both the ANSn register and
the corresponding TRIS register bits control the opera-
tion of the A/D port pins. The port pins that will function
as analog inputs must also have their corresponding
TRIS bits set, specifying the pins as inputs. After a
device Reset, all TRIS bits are set. If the I/O pin asso-
ciated with an A/D channel is configured as a digital
output (TRIS bit is cleared), while the pin is configured
for Analog mode, the port digital output level (VOH or
VOL) will be converted.
22.3.5 INPUT CHANNEL SELECTION
The A/D Converter incorporates two independent sets
of input multiplexers (MUX A and MUX B) that allow
users to choose which analog channels are to be sam-
pled. The inputs specified by the CH0SAx and CH0NAx
bits are collectively called the MUX A inputs. The inputs
specified by the CH0SBx and CH0NBx bits are collec-
tively called the MUX B inputs.
Functionally, MUX A and MUX B are very similar to each
other. Both multiplexers allow any of the analog input
channels to be selected for individual sampling and
allow selection of a negative reference source for differ-
ential signals. In addition, MUX A can be configured for
sequential analog channel scanning. This is discussed
in more detail in Section 22.3.5.1 “Configuring MUX A
And MUX B Inputs” and Section 22.3.5.3 “Scanning
Through Several Inputs”.
22.3.5.1 Configuring MUX A And MUX B
Inputs
The user may select any one of up to 32 inputs avail-
able to the A/D Converter as the positive input of the
S/H amplifier. For MUX A, the CH0SA<4:0> bits
(ADCHS0L<4:0>) normally select the analog channel
for the positive input. For MUX B, the positive channel
is selected by the CH0SB<4:0> bits (ADCHS0H<4:0>).
All of the external analog channels are available as
positive inputs. In addition to the external inputs, these
may also include device supply voltage (AVDD), the
logic core supply voltage (VDDCORE), the internal band
gap voltage (VBG) and/or multiples or fractions of VBG.
One or more additional input channels are used for the
CTMU. These selections leave the A/D disconnected
from all other inputs. The options vary by device family;
refer to the specific device data sheet for details.
TCY (ADCSx + 1)
ADCSX =– 1
TAD
TCY
Note: Based on TCY = 2/FOSC; Doze mode
TAD =
and PLL are disabled.
Note 1: When reading a PORT register, any pin
configured as an analog input reads as
‘0’.
2: Analog levels on any pin that is defined
as a digital input may cause the input
buffer to consume current that is out of
the device’s specification.
Note: Different PIC18F devices will have
different numbers of analog inputs. Verify
the analog input availability against the
particular device’s data sheet.
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The CTMU input is selected by the ADCTMUEN1H/L,
ADCTMUEN0H/L registers. Setting a particular bit in
one of these registers effectively assigns the analog
output from the CTMU to the corresponding A/D input
channel, automatically enabling the CTMU. Many
devices will already have a CH0SAx bit combination
designated for use of the CTMU. This setting discon-
nects the converter from any other load. This channel
should be the one selected by the appropriate
ADCTMUEN bit. If another channel is selected, verify
that any other analog sources are disconnected from
that channel; otherwise, erroneous readings may
result.
For the negative (inverting) input of the amplifier, the
user has up to eight options, selected by the
CH0NA<2:0> and CH0NB<2:0> bits (ADCHS0L<7:5>
and ADCHS0H<7:5>, respectively). Options typically
include the device ground (AVSS), the current VR-
source designated by the NVCFG0 bit
(ADCON2H<5>), and one or more of the external
analog input channels. As with the non-inverting inputs,
the options vary by device family.
22.3.5.2 Alternating MUX A And MUX B Input
Selections
By default, the A/D Converter only samples and con-
verts the inputs selected by MUX A. The ALTS bit
(ADCON2L<0>) enables the module to alternate
between two sets of inputs selected by MUX A and
MUX B during successive samples.
If the ALTS bit is '0', only the inputs specified by the
CH0SAx and CH0NAx bits are selected for sampling.
When the ALTS bit is '1', the module will alternate
between the MUX A inputs on one sample and the
MUX B inputs on the subsequent sample.
If the ALTS bit is '1' on the first sample/convert
sequence, the inputs specified by the CH0SAx and
CH0NAx bits are selected for sampling. On the next
sample/convert sequence, the inputs specified by the
CH0SBx and CH0NBx bits are selected for sampling.
This pattern repeats for subsequent sample conversion
sequences.
22.3.5.3 Scanning Through Several Inputs
When using MUX A to select analog inputs, the A/D
module has the ability to scan multiple analog chan-
nels. When the CSCNA bit (ADCON2H<>) is set, the
CH0SA bits are ignored and the channels specified by
the ADCSS1H/L, ADCSS0H/L registers are sequen-
tially sampled.
Each bit in the ADCSS1H/L registers and ADCSS0H/L
registers (when implemented) corresponds to one of
the analog channels. If a bit in the ADCSS0H/L or
ADCSS1H/L registers is set, the corresponding analog
channel is included in the scan sequence. Inputs are
always scanned from lower to higher numbered inputs,
starting at the first selected channel after each interrupt
occurs.
The ADCSS1H/L, ADCSS0H/L registers' bits specify
the positive input of the channel. The CH0NAx bits still
select the negative input of the channel during
scanning.
Scanning is only available on the MUX A input
selection. The MUX B input selection, as specified by
the CH0SBx bits, will still select the alternating input.
When alternated sampling between MUX A and MUX
B is selected (ALTS = 1), the input will alternate
between a set of scanning inputs specified by the
ADCSS1H/L, ADCSS0H/L registers, and a fixed input
specified by the CH0SBx bits.
Automatic scanning can be used in conjunction with the
Threshold Detect feature to determine if one or more
analog channels meet a predetermined set of condi-
tions while the CPU is inactive. This is described in
detail in Section 22.7 “Threshold Detect Operation”.
22.3.5.4 Internal Channels In Low-power
Modes
While the A/D module can scan and convert analog
inputs in low-power modes, some internal analog
inputs may be unavailable in Sleep mode. The main
examples are the CTMU module, the internal band gap
voltage source and the on-chip voltage regulator (for
those devices that include one). The A/D module
provides a method to make these resources available
automatically through the CTMUREQ bit
(ADCON5H<5>). Setting one or more of these bits
causes the corresponding internal analog source(s) to
become active during a channel scan.
22.3.6 ENABLING THE MODULE
When the ADON bit (ADCON1H<7>) is set, the module
is fully powered and functional. When ADON is '0', the
module is disabled. Although the digital and analog
portions of the circuit are turned off for maximum
current savings, the contents of all registers are
maintained.
Note 1: If the number of scanned inputs selected
is greater than the number of samples
taken per interrupt, the higher numbered
inputs will not be sampled.
2: If the CTMU channel is to be included in
a scan operation, verify that the proper
analog input channel is selected and that
the AD1CTMEN register(s) are correctly
configured. For more information, see
Section 22.3.5.1 “Configuring MUX A
And MUX B Inputs”.
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Conversion data stored in the ADCBUF registers will
also be maintained, including any threshold values
stored by the user. It may be necessary to re-initialize
these registers to their proper values before
re-enabling the module.
When enabling the module by setting the ADON bit, the
user must wait for the analog stages to stabilize. For
the stabilization time, refer to Section 31.0 “Electrical
Characteristics”.
22.4 Controlling the Sampling Process
22.4.1 MANUAL SAMPLING
Setting the SAMP bit (ADCON1L<1>) while the ASAM
bit (ADCON1L<2>) is clear causes the A/D to begin
sampling. Clearing the SAMP bit ends sampling and
automatically begins the conversion; however, there
must be a sufficient delay between setting and clearing
SAMP for the sampling process to start. Sampling will
not resume until the SAMP bit is once again set. For an
example, see Figure 22-4.
22.4.2 AUTOMATIC SAMPLING
Setting the ASAM bit causes the A/D to automatically
begin sampling after a conversion has been completed.
One of several options can be used as an event to end
sampling and complete the conversions. Sampling will
continue on the next selected channel after the conver-
sion in progress has completed. For an example, see
Figure 22-5.
22.4.3 MONITORING SAMPLE STATUS
The SAMP bit indicates the sampling state of the A/D.
Generally, when the SAMP bit clears, indicating the
end of sampling, the DONE bit is automatically cleared
to indicate the start of conversion. If SAMP is '0' while
DONE is '1', the A/D is in an inactive state.
22.4.4 ABORTING A SAMPLE
While in Manual Sampling mode, clearing the SAMP bit
will terminate sampling. If SSRC<3:0> = 0000, it may
also start a conversion automatically.
Clearing the ASAM bit while in Automatic Sampling
mode will not terminate an ongoing sample/convert
sequence; however, sampling will not automatically
resume after a subsequent conversion.
22.5 Controlling the Conversion
Process
The conversion trigger source will terminate sampling
and start a selected sequence of conversions. The
SSRC<3:0> bits (ADCON1L<7:4>) select the source of
the conversion trigger.
22.5.1 MANUAL CONTROL
When SSRC<3:0> = 0000, the conversion trigger is
under software control. Clearing the SAMP bit
(ADCON1L<1>) starts the conversion sequence.
Figure 22-4 is an example where setting the SAMP bit
initiates sampling, and clearing the SAMP bit
terminates sampling and starts conversion. The user
software must time the setting and clearing of the
SAMP bit to ensure adequate sampling time of the
input signal.
Figure 22-5 is an example where setting the ASAM bit
initiates automatic sampling, and clearing the SAMP bit
terminates sampling and starts conversion. After the
conversion completes, the module sets the SAMP bit
and returns to the sample state. The user software
must time the clearing of the SAMP bit to ensure
adequate sampling time of the input signal, under-
standing that the time since previously clearing the
SAMP bit includes the conversion time, which immedi-
ately follows, as well as the next sampling time.
Note 1: The available conversion trigger sources
may vary depending on the PIC18F
device variant. Refer to the specific
device data sheet for the available
conversion trigger sources.
2: The SSRCx selection bits should not be
changed when the A/D module is
enabled. If the user wishes to change
the conversion trigger source, disable the
A/D module first by clearing the ADON bit
(AD1CON1<15>).
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FIGURE 22-4: CONVERTING ONE CHANNEL, MANUAL SAMPLE START, MANUAL
CONVERSION START
EXAMPLE 22-1: CONVERTING ONE CHANNEL, MANUAL SAMPLE START, MANUAL
CONVERSION START CODE
FIGURE 22-5: CONVERTING ONE CHANNEL, AUTOMATIC SAMPLE START, MANUAL
CONVERSION START
A/D CLK
SAMP
ADC1BUF0
TSAMP TCONV
BCF AD1CON1, SAMPBSF AD1CON1, SAMP
Instruction Execution
DONE
int ADCValue;
ANSB = 0x0001; // AN2 as analog, all other pins are digital
AD1CON1 = 0x0000; // SAMP bit = 0 ends sampling and starts converting
AD1CHS = 0x0002; // Connect AN2 as S/H+ input
// in this example AN2 is the input
AD1CSSL = 0;
AD1CON3 = 0x0002; // Manual Sample, Tad = 3Tcy
AD1CON2 = 0;
AD1CON1bits.ADON = 1; // turn ADC ON
while (1) // repeat continuously
{
AD1CON1bits.SAMP = 1; // start sampling...
Delay(); // Ensure the correct sampling time has elapsed
// before starting conversion.
AD1CON1bits.SAMP = 0; // start converting
while (!AD1CON1bits.DONE){}; // conversion done?
ADCValue = ADC1BUF0; // yes then get ADC value
}
A/D CLK
SAMP
ADC1BUF0
TSAMP TCONV
BCF AD1CON1, SAMP
TCONV
BSF AD1CON1, ASAM BCF AD1CON1, SAMP
TSAMP
TAD0TAD0
Instruction Execution
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22.5.2 CLOCKED CONVERSION TRIGGER
When ADRC = 1, the conversion trigger is under A/D
clock control. The SAMCx bits (ADCON3H<4:0>)
select the number of TAD clock cycles between the
start of sampling and the start of conversion. After the
start of sampling, the module will count a number of
TAD clocks specified by the SAMCx bits. The SAMCx
bits must always be programmed for at least one clock
cycle to ensure sampling requirements are met.
EQUATION 22-2: CLOCKED CONVERSION
TRIGGER TIME
Figure 22-6 shows how to use the clocked conversion
trigger with the sampling started by the user software.
FIGURE 22-6: CONVERTING ONE CHANNEL, MANUAL SAMPLE START, TAD-BASED
CONVERSION START
EXAMPLE 22-2: CONVERTING ONE CHANNEL, MANUAL SAMPLE START, TAD-BASED
CONVERSION START CODE
TSMP = SAMC<4:0> * TAD
A/D CLK
SAMP
ADC1BUF0
TSAMP TCONV
BSF AD1CON1, SAMPInstruction Execution
DONE
int ADCValue;
ANSB = 0x1000; // all PORTB = Digital; RB12 = analog
AD1CON1 = 0x00E0; // SSRC<2:0> = 111 implies internal counter ends sampling
// and starts converting.
AD1CHS = 0x000C; // Connect AN12 as S/H input.
// in this example AN12 is the input
AD1CSSL = 0;
AD1CON3 = 0x1F02; // Sample time = 31Tad, Tad = 3Tcy
AD1CON2 = 0;
AD1CON1bits.ADON = 1; // turn ADC ON
while (1) // repeat continuously
{
AD1CON1bits.SAMP = 1; // start sampling, then after 31Tad go to conversion
while (!AD1CON1bits.DONE){}; // conversion done?
ADCValue = ADC1BUF0; // yes then get ADC value
} // repeat
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22.5.2.1 Free-running Sample Conversion
Sequence
Using the Auto-Convert Conversion Trigger mode
(SSRC<3:0> = 0111), in combination with the
Auto-Sample Start mode (ASAM = 1), allows the A/D
module to schedule sample/conversion sequences
with no intervention by the user or other device
resources. This “Clocked” mode, shown in Figure 22-7,
allows continuous data collection after module initial-
ization.
Note that all timing in this mode scales with TAD, either
from the A/D internal RC clock or from TCY (as
prescaled by the ADCS<7:0> bits). In both cases, the
SAMC<4:0> bits set the number of TAD clocks in
TSAMP. TCONV is fixed at 12 TAD.
FIGURE 22-7: CONVERTING ONE CHANNEL, AUTO-SAMPLE START, TAD-BASED
CONVERSION START
22.5.2.2 Sample Time Considerations Using
Clocked Conversion Trigger And
Automatic Sampling
The user must ensure the sampling time satisfies the
sampling requirements, as outlined in Section 22.9
“A/D Sampling Requirements”. Assuming that the
module is set for automatic sampling and using a
clocked conversion trigger, the sampling interval is
specified by the SAMCx bits.
22.5.3 EVENT TRIGGER CONVERSION
START
It is often desirable to synchronize the end of sampling
and the start of conversion with some other time event.
Depending on the device family, the A/D module has up
to 16 sources available to use as a conversion trigger
event. The event trigger is selected by the SSRC<3:0>
bits (ADCON1L<7:4>).
As noted, the available event triggers vary between
device families. Refer to the specific device data sheet
for specific information. The examples that follow
represent trigger sources that are implemented in most
devices. Note that the SSRCx bit assignments may
vary in some devices.
22.5.3.1 External Int0 Pin Trigger
When SSRC<3:0> = 0001, the A/D conversion is
triggered by an active transition on the INT0 pin. The
pin may be programmed for either a rising edge input
or a falling edge input.
22.5.3.2 Special Event Trigger
When SSRC<3:0> = 0010, the A/D is triggered by a
Special Event Trigger. Refer to CCP and ECCP section
for more information about Special Event Triggers.
22.5.3.3 Synchronizing A/D Operations To
Internal Or External Events
The modes where an external event trigger pulse ends
sampling and starts conversion may be used in combi-
nation with auto-sampling (ASAM = 1) to cause the A/D
to synchronize the sample conversion events to the
trigger pulse source. For example, in Figure 22-9,
where SSRC<3:0> = 0010 and ASAM = 1, the A/D will
always end sampling and start conversions synchro-
nously with the timer compare trigger event. The A/D
will have a sample conversion rate that corresponds to
the timer comparison event rate.
A/D CLK
SAMP
ADC1BUF1
TSAMP TCONV
DONE
TSAMP TCONV
ADC1BUF0
BSF AD1CON1, ASAM
Instruction Execution
Reset by
Software
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22.5.3.4 Sample Time Considerations For
Automatic Sampling/conversion
Sequences
Different sample/conversion sequences provide differ-
ent available sampling times for the S/H channel to
acquire the analog signal. The user must ensure the
sampling time satisfies the sampling requirements, as
outlined in Section 22.9 “A/D Sampling Require-
ments”.
Assuming that the module is set for automatic sam-
pling, and an external trigger pulse is used as the con-
version trigger, the sampling interval is a portion of the
trigger pulse interval. The sampling time is the trigger
pulse period, less the time required to complete the
conversion.
EQUATION 22-3: CALCULATING AVAILABLE SAMPLING TIME FOR SEQUENTIAL SAMPLING
FIGURE 22-8: MANUAL SAMPLE START, CONVERSION TRIGGER-BASED CONVERSION
START
FIGURE 22-9: AUTO-SAMPLE START, CONVERSION TRIGGER-BASED CONVERSION START
TSMP = Trigger Pulse Interval (TSEQ) – Conversion Time (TCONV) = TSEQ – TCONV
Conversion Trigger
A/D CLK
SAMP
ADC1BUF0
TSAMP TCONV
BSF AD1CON1, SAMP
Instruction Execution
Conversion Trigger
A/D CLK
SAMP
ADC1BUF0
TSAMP TCONV
BSF AD1CON1, ASAM
TCONVTSAMP
ADC1BUF1
DONE
Reset by
Software
Instruction Execution
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22.5.4 MONITORING
SAMPLE/CONVERSION STATUS
The DONE bit (ADCON1L<0>) indicates the conver-
sion state of the A/D. Generally, when the SAMP bit
clears, indicating the end of sampling, the DONE bit is
automatically cleared to indicate the start of conver-
sion. If SAMP is '0' while DONE is '1', the A/D is in an
inactive state.
In some operational modes, the SAMP bit may also
invoke and terminate sampling. In these modes, the
DONE bit cannot be used to terminate conversions in
progress.
22.5.5 GENERATING A/D INTERRUPTS
The SMPI<4:0> bits (ADCON2L<6:2>) control the
generation of the A/D Interrupt Flag, ADIF. The A/D
Interrupt Flag is set after the number of sample/conver-
sion sequences is specified by the SMPIx bits, after the
start of sampling, and continues to recur after that
number of samples. The value specified by the SMPIx
bits also corresponds to the number of data samples in
the buffer, up to the maximum of 16. To enable the
interrupt, it is necessary to set the A/D Interrupt Enable
bit, ADIE.
If auto-scan is enabled (ADCON5<7> = 1), interrupt
generation is controlled by the ASINTMDx bits
(ADCON5H<1:0>). For more information, refer to
Section 22.7.4 “Threshold Detect Interrupts”.
22.5.6 ABORTING A CONVERSION
Clearing the ADON bit during a conversion will abort
the current conversion. The A/D results buffer will not
be updated with the partially completed A/D conversion
sample; that is, the corresponding ADCBUF buffer
location will continue to contain the value of the last
completed conversion (or the last value written to the
buffer).
22.5.7 OFFSET CALIBRATION
The module provides a simple calibration method to
offset the effects of internal device noise. While not
always necessary, this may be helpful in situations
where weak analog signals are being converted.
Calibration is performed by using the OFFCAL bit
(ADCON2H<4>). This disconnects the S/H amplifier
entirely from any inputs. With the OFFCAL bit set, a
single reference conversion is performed. The results
of this conversion are value added by internal device
noise. This result can be stored by the application, then
used as an offset value for future conversions.
22.6 A/D Results Buffer
As conversions are completed, the module writes the
results of the conversions into the A/D result buffer.
This buffer is a RAM array of fixed word size, accessed
through the SFR space. The size of the buffer is deter-
mined by the number of external analog input channels
on the device, allowing one word for each channel.
Depending on the device, additional buffer space may
be provided for one or more internal analog channels
(e.g., band gap sources). The number of buffer
addresses is always even and always at least equal to
the number of external channels.
User software may attempt to read each A/D conver-
sion result as it is generated; however, this might
consume too much CPU time. Generally, to minimize
software overhead, the module will fill the buffer with
results and then generate an interrupt when the buffer
is filled.
22.6.1 NUMBER OF CONVERSIONS PER
INTERRUPT
The SMPI<4:0> bits select how many A/D conversions
will take place before the CPU is interrupted. This can
vary from 1 to 16 samples per interrupt. The A/D
Converter module always starts writing its conversion
results at the beginning of the buffer, after each
interrupt. For example, if SMPI<4:0> = 00000, the
conversion results will always be written to the
ADCBUF0. In this example, no other buffer locations
would be used, since only one sequence per interrupt
is specified.
22.6.2 BUFFER FILL MODES
The results buffer can be configured to operate in either
of two modes: a standard FIFO mode, compatible with
the earlier 10-bit A/D module (default), or a Channel
Indexed mode. The Fill mode is selected by the
BUFREGEN bit (ADCON2H<3>).
22.6.2.1 FIFO Modes
When BUFREGEN = 0, the results buffer operates in
FIFO mode. The first conversion results, after initiating
conversions, is written to the first available buffer
address. Subsequent conversions are written to the
next sequential buffer location, continuing until the
process is interrupted. If allowed to continue without
interrupts, the module would fill each location and then
wrap around to the first address, continuing the
process.
Note: This section describes buffer operation in
Legacy mode (AD1CON5<3:2> = 00).
Buffer operation is different when the
Compare Only or Compare and Save
modes are used with the Threshold Detect
feature. For more information, see Section
22.7 “Threshold Detect Operation”.
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The BUFM bit (ADCON2L<1>) controls how the buffer
is filled. When BUFM is '1', the buffer is split into two
equal halves: a lower half (ADCBUF0 through
ADCBUF[(n/2) - 1]) and an upper half (ADCBUF[n/2]
through ADCBUFn), where n is the number of available
analog channels (both internal and external). The
buffers will alternately receive the conversion results
after each interrupt event. The initial buffer used after
BUFM is set is the lower group.
When BUFM is '0', the entire buffer is used for all
conversion sequences.
The decision to use the split buffer feature will depend
upon how much time is available to move the buffer
contents after the interrupt, as determined by the
application. If the application can quickly unload a full
buffer within the time it takes to sample and convert one
channel, the BUFM bit can be '0', and up to 16 conver-
sions may be done per interrupt. The application will
have one sample/convert time before the first buffer
location is overwritten.
If the processor cannot unload the buffer within the
sample and conversion time, the BUFM bit should be
'1'. For example, if SMPI<4:0> = 00111, then eight
conversions will be loaded into the lower half of the
buffer, following which, an interrupt may occur. The
next eight conversions will be loaded into the upper half
of the buffer. The processor will, therefore, have the
entire time between interrupts to move the eight
conversions out of the buffer.
22.6.2.2 Buffer Fill Status
When the conversion result buffer is split (BUFM = 1),
the BUFS status bit (ADCON2L<7>) indicates which
half of the buffer that the A/D Converter is currently writ-
ing. If BUFS = 0, the A/D Converter is filling the lower
group and the user application should read conversion
values from the upper group. If BUFS = 1, the situation
is reversed, and the user application should read
conversion values from the lower group.
22.6.2.3 Channel Indexed Mode
When BUFREGEN = 1, FIFO operation is disabled. In
this Fill mode, the conversion result for each channel is
written only to the buffer location that corresponds to
that channel. For example, any conversions performed
on AN0 are stored only in ADCBUF0. The same holds
true for AN1 and ADCBUF1, and so on. Subsequent
conversions on a particular channel that occur, prior to
an interrupt, will result in any previous data in that
location being overwritten.
Channel Indexed mode is particularly useful when used
with the Threshold Detect feature, as this allows the
user to easily test for a particular condition on a specific
analog channel without creating an excess of CPU
overhead. This is covered in more detail in Section
22.7 “Threshold Detect Operation”.
22.6.3 BUFFER DATA FORMATS
The results of each A/D conversion are 12 bits wide
(optionally, 10 bits wide in some devices). To maintain
data format compatibility, the result of each conversion
is automatically converted to one of four selectable,
16-bit formats. The FORM<1:0> bits (ADCON1H<1:0>)
select the format. Figure 22-10 and Figure 22-11 show
the data output formats that can be selected.
Table 22-2 through Table 22-5 show the numerical
equivalents for the various conversion result codes.
FIGURE 22-10: A/D OUTPUT DATA FORMATS (12-BIT)
Note: When the BUFM bit is set, the user
should not program the SMPIx bits to a
value that specifies more than (n/2)
conversions per interrupt.
RAM Contents: d11 d10 d09 d08 d07 d06 d05 d04 d03 d02 d01 d00
Read to Bus:
Integer 0000d11d10d09d08d07d06d05d04d03d02d01d00
Signed Integer d11 d11 d11 d11 d11 d10 d09 d08 d07 d06 d05 d04 d03 d02 d01 d00
Fractional (1.15) d11 d10 d09 d08 d07 d06 d05 d04 d03 d02 d01 d00 0 0 0 0
Signed Fractional (1.15) d11 d10 d09 d08 d07 d06 d05 d04 d03 d02 d01 d00 0 0 0 0
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TABLE 22-2: NUMERICAL EQUIVALENTS OF VARIOUS RESULT CODES: 12-BIT INTEGER
FORMATS
TABLE 22-3: NUMERICAL EQUIVALENTS OF VARIOUS RESULT CODES: 12-BIT FRACTIONAL
FORMATS
FIGURE 22-11: A/D OUTPUT DATA FORMATS (10-BIT)
VIN/VREF 12-Bit
Output Code
16-Bit Integer Format/
Equivalent Decimal Value
16-Bit Signed Integer Format/
Equivalent Decimal Value
4095/4096 1111 1111 1111 0000 1111 1111 1111 4095 0000 0111 1111 1111 2047
4094/4096 1111 1111 1110 0000 1111 1111 1110 4094 0000 0111 1111 1110 2046
2049/4096 1000 0000 0001 0000 1000 0000 0001 2049 0000 0000 0000 0001 1
2048/4096 1000 0000 0000 0000 1000 0000 0000 2048 0000 0000 0000 0000 0
2047/4096 0111 1111 1111 0000 0111 1111 1111 2047 1111 1111 1111 1111 -1
1/4096 0000 0000 0001 0000 0000 0000 0001 11111 1000 0000 0001 -2047
0/4096 0000 0000 0000 0000 0000 0000 0000 01111 1000 0000 0000 -2048
VIN/VREF 12-Bit
Output Code
16-Bit Fractional Format/
Equivalent Decimal Value
16-Bit Signed Fractional Format/
Equivalent Decimal Value
4095/4096 1111 1111 1111 1111 1111 1111 0000 0.999 0111 1111 1111 0000 0.499
4094/4096 1111 1111 1110 1111 1111 1110 0000 0.998 0111 1111 1110 0000 0.498
2049/4096 1000 0000 0001 1000 0000 0001 0000 0.501 0000 0000 0001 0000 0.001
2048/4096 1000 0000 0000 1000 0000 0000 0000 0.500 0000 0000 0000 0000 0.000
2047/4096 0111 1111 1111 0111 1111 1111 0000 0.499 1111 1111 1111 0000 -0.001
1/4096 0000 0000 0001 0000 0000 0001 0000 0.001 1000 0000 0001 0000 -0.499
0/4096 0000 0000 0000 0000 0000 0000 0000 0.000 1000 0000 0000 0000 -0.500
RAM Contents: d09 d08 d07 d06 d05 d04 d03 d02 d01 d00
Read to Bus:
Integer 000000d09 d08 d07 d06 d05 d04 d03 d02 d01 d00
Signed Integer d09 d09 d09 d09 d09 d09 d09 d08 d07 d06 d05 d04 d03 d02 d01 d00
Fractional (1.15) d09 d08 d07 d06 d05 d04 d03 d02 d01 d00 000000
Signed Fractional (1.15) d09 d08 d07 d06 d05 d04 d03 d02 d01 d00 000000
2012 Microchip Technology Inc. DS30575A-page 469
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TABLE 22-4: NUMERICAL EQUIVALENTS OF VARIOUS RESULT CODES: 10-BIT INTEGER
FORMATS
TABLE 22-5: NUMERICAL EQUIVALENTS OF VARIOUS RESULT CODES: 10-BIT FRACTIONAL
FORMATS
22.7 Threshold Detect Operation
Threshold Detect is a significant extension of the
Auto-Scan feature offered in previous 10-bit A/D mod-
ules. In addition to being able to repeatedly sample a
predefined sequence of analog channels, Threshold
Detect allows the user to define match conditions
based on the conversion results and generate an inter-
rupt based on these conditions. During normal opera-
tion, this can potentially reduce the amount of CPU
time spent on processing A/D interrupts. For low-power
applications, this can allow the CPU to remain inactive
for longer periods, waking only when specific analog
conditions are met.
When selected by the user, Threshold Detect changes
the operation of the A/D results buffer by making it a
read/write array for both conversion results and com-
parison (threshold) values. It also brings into play the
AD1CHIT registers, which are used to indicate match
conditions. Independently selectable comparison and
buffer storage settings make a wide range of operating
combinations possible.
22.7.1 OPERATING MODES
The operation of Threshold Detect is mostly controlled
by the ADCON5H/L registers. The ASENA bit
(ADCON5L<7>) controls overall operation of
Threshold Detect; setting this bit enables the
functionality.
As with Legacy Auto-Scan operation, the channels to
be included are selected using the ADCSS1H/L,
ADCSS0H/L registers. Setting a particular bit in either
register includes the corresponding channel in an
automatic sequential scan. One or more channels may
be selected. After the channels have been selected,
setting both the CSCNA and ASENA bits to enable a
single scan of the designated channels. The scan itself
is triggered by the trigger source programmed by the
SSRC<3:0> bits.
.
VIN/VREF 10-Bit
Output Code
16-Bit Integer Format/
Equivalent Decimal Value
16-Bit Signed Integer Format/
Equivalent Decimal Value
1023/1024 11 1111 1111 0000 0011 1111 1111 1023 0000 0001 1111 1111 511
1022/1024 11 1111 1110 0000 0011 1111 1110 1022 0000 0001 1111 1110 510
513/1024 10 0000 0001 0000 0010 0000 0001 513 0000 0000 0000 0001 1
512/1024 10 0000 0000 0000 0010 0000 0000 512 0000 0000 0000 0000 0
511/1024 01 1111 1111 0000 0001 1111 1111 511 1111 1111 1111 1111 -1
1/1024 00 0000 0001 0000 0000 0000 0001 11111 1110 0000 0001 -511
0/1024 00 0000 0000 0000 0000 0000 0000 01111 1110 0000 0000 -512
VIN/VREF 10-Bit
Output Code
16-Bit Fractional Format/
Equivalent Decimal Value
16-Bit Signed Fractional Format/
Equivalent Decimal Value
1023/1024 11 1111 1111 1111 1111 1100 0000 0.999 0111 1111 1100 0000 0.499
1022/1024 11 1111 1110 1111 1111 1000 0000 0.998 0111 1111 1000 0000 0.498
513/1024 10 0000 0001 1000 0000 0100 0000 0.501 0000 0000 0100 0000 0.001
512/1024 10 0000 0000 1000 0000 0000 0000 0.500 0000 0000 0000 0000 0.000
511/1024 01 1111 1111 0111 1111 1100 0000 0.499 1111 1111 1100 0000 -0.001
1/1024 00 0000 0001 0000 0000 0100 0000 0.001 1000 0000 0100 0000 -0.499
0/1024 00 0000 0000 0000 0000 0000 0000 0.000 1000 0000 0000 0000 -0.500
Note: Legacy Auto-Scan (i.e., sequential
scanning of analog channels on MUX A,
without any comparison) is controlled by
the CSCNA bit (AD1CON2<10>) and
does not depend on the ASEN bit to
function
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The LPENA bit (ADCON5H<6>) allows Threshold
Detect to function with a low-power feature. By design,
Threshold Detect can perform comparison operations
when the device is in Sleep or Idle modes, waking the
CPU when it generates an interrupt. Setting LPENA
configures the device to return to low-power operation
after the interrupt has been serviced.
The Compare Mode bits, CM<1:0> (ADCON5L<1:0>),
select the type of comparison to be performed. Four
types are available:
• The result of the current conversion is greater
than a reference threshold
• The result of the current conversion is less than a
reference threshold
• The result of the current conversion is between
two predefined thresholds (“Inside Window”)
• The result of the current conversion is outside of
the predefined thresholds (“Outside Window”)
The Write Mode bits, WM<1:0> (ADCON5L<3:2>),
determine the disposition of the conversion. Three
options are available:
• Discard the conversion after the comparison has
been performed
• Store the conversion after the comparison has
been performed
• Store the conversion without comparison (Legacy
mode)
22.7.1.1 Buffer Operation And Comparisons
For Buffer Write modes that involve storing conver-
sions (WM<1:0> = 0x), the BUFM and BUFREGEN
bits control how the buffer functions (as a channel
indexed, single FIFO or split FIFO buffer). However,
when the compare and store option is selected
(WM<1:0> = 01), using a FIFO mode may overwrite the
buffers of other channels and cause unpredictable
comparison results. For that reason, always use
Channel Indexed Buffer mode (BUFREGEN = 1) when
using the compare and store option.
22.7.1.2 Buffer Operation In Windowed
Comparisons (Channel Mirroring)
The use of windowed comparisons changes the avail-
able options for the results buffer. To accommodate the
storage of two threshold values, the buffer is automati-
cally split into halves, similar to Split FIFO mode. Buffer
addresses in each half are paired, with the lowest
address in one buffer, matched to the buffer address in
the upper half. (For example, in a 16-word buffer,
ADCBUF0 is paired with ADCBUF9, ADCBUF1 is
paired with ADCBUF10, and so on.) This pairing is
referred to as “channel mirroring”.
Mirroring can obviously be applied only to the lower
A/D channels; for most devices, this corresponds to the
lower half of the external analog channels. This does
not mean that those buffer locations cannot be used for
other purposes. However, storing any other data in a
particular buffer location, where channel mirroring is
being used, may result in misleading comparison
evaluations.
22.7.2 SETTING COMPARISON
THRESHOLDS
The comparison thresholds for Threshold Detect are
set by writing the desired values to an appropriate
location in the A/D results buffer. This can only be done
when the module is deactivated (ADCON1H<7> = 0).
The location of the threshold is determined by the
comparison type. For simple greater than, and less
than, comparisons, the value is written to the buffer
location corresponding to the input channel to be
monitored. For example, if AN0 is to be monitored for a
voltage over a certain level, the ceiling threshold is
stored in ADCBUF0.
The location of the thresholds for windowed compari-
sons are written to two addresses. The lower value is
written to the address corresponding to the monitored
channel. The upper value is stored in the correspond-
ing mirrored address in the upper half of the buffer. To
expand on the previous example, if the conversion on
AN0 is to be a windowed comparison, the floor thresh-
old is stored in ADCBUF0, while the ceiling threshold is
stored in ADCBUF9.
22.7.3 COMPARE HIT REGISTERS
To determine if a particular event has occurred, the A/D
module uses two registers to record match events.
These registers are referred to as the Compare Hit
registers and are designated, ADCHIT1H/L and
ADCHIT0H/L. The registers map their individual bits
sequentially to each of the (up to) 32 analog channels.
If a particular channel in a device is not implemented,
the corresponding Compare Hit bit (CHHn) is not
implemented.
Each bit serves as an event semaphore for its corre-
sponding channel. When the programmed event
occurs on that channel, the bit becomes set and stays
set until it is cleared by the application. It is the user's
responsibility to clear the bits after the application has
evaluated them.
Depending on the event, more than one Compare Hit bit
may be set. The significance of a set bit must be inter-
preted by the application in the context of the Compare
mode selected. Particular examples are covered in
Section 22.7.5 “Comparison Mode Examples”.
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22.7.4 THRESHOLD DETECT
INTERRUPTS
The A/D module can generate an interrupt and set the
ADIF flag based on Threshold Detect operation. This
is based on completion of a Threshold Detect
sequence and/or the occurrence of a valid compari-
son. When Threshold Detect is enabled (ASENA = 1),
A/D module interrupt generation is governed by the
ASINTMDx bits (ADCON5H<1:0>), superseding any
configuration implemented by the SMPIx bits
(ADCON2L<6:2>). For information on alternative
interrupt settings, refer to Section 22.6.1 “Number of
Conversions Per Interrupt”.
The Threshold Detect interrupt is configured by the
ASINTMD<1:0> bits (ADCON5H<1:0>). Options
include interrupt after a scan sequence, interrupt after
a scan sequence with a valid match, interrupt after a
valid match (without waiting for the sequence to end) or
no interrupt.
22.7.5 COMPARISON MODE EXAMPLES
The following examples show the effect of valid
comparisons on the results buffer and the
Compare Hit registers. In each figure, changes within
the registers are indicated in bold.
For the sake of simplicity, the examples assume a
device with only 16 analog inputs. Devices with a
greater number of channels, and thus, larger results
buffers and two Compare Hit registers, will function in a
similar fashion.
22.7.5.1 Simple Comparisons (Greater And
Less Than Results)
When the Compare Mode bits, CM<1:0>
(ADCON5L<1:0>), are programmed as '0x', the
converter compares the sampled value to see if it is
greater than (CM<1:0> = 01), or less than (CM<1:0> =
00), the threshold value in the buffer location. If the
condition is met, both of the following occur:
• The Compare Hit bit (CHHn) for the correspond-
ing channel is set.
• If the Write Mode bits, WM<1:0>
(ADCON5L<3:2>), are programmed to '01', the
converted value is written to the buffer, replacing
the threshold value. If WM<1:0> = 10, the
converted value is discarded.
The changes to the result buffer and the Compare Hit
register are shown in Figure 22-13. Note that they are
the same for both types of simple comparison.
Note: When using any comparison mode,
always use channel indexed buffer
storage (BUFREGEN = 1). Otherwise,
the threshold values for other channels
may be overwritten, resulting in
unpredictable comparisons.
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FIGURE 22-12: SIMPLE COMPARISON OPERATIONS (GREATER THAN AND LESS THAN)
22.7.5.2 Inside Window Comparison
When the Compare Mode bits, CM<1:0>, are
programmed as '10', the converter compares the sam-
pled value to see if it falls between the threshold values
in the buffer and mirrored channel location. Since the
value in the mirrored channel location is always the
greater value of the two thresholds, the condition is met
when:
Threshold 2 > Converted Value > Threshold 1
In this case, both of the following occur:
• The Compare Hit bit (CHHn) for the correspond-
ing channel is set; the Compare Hit bit for the
mirrored channel remains cleared.
• If the Write Mode bits, WM<1:0>
(ADCON5L<3:2>), are programmed to '01', the
converted value is written to the buffer, replacing
the lower threshold value. If WM<1:0> = 10, the
converted value is discarded.
The changes to the result buffer and the Compare Hit
register are shown in Figure 22-14.
ADC1BUF15 —
ADC1BUF14 —
ADC1BUF13 —
ADC1BUF12 —
ADC1BUF11 —
ADC1BUF10 —
ADC1BUF9 —
ADC1BUF8 —
ADC1BUF7 —
ADC1BUF6 —
ADC1BUF5 —
ADC1BUF4 —
ADC1BUF3 —
ADC1BUF2 Threshold Value
ADC1BUF1 —
ADC1BUF0 —
Before Conversion and Comparison
AD1CHITL
15 14 13 12 11 10 9 8
0000000 0
76543210
00000100
After Conversion and Comparison
Compare Only
(‘10’)
Compare and
Store (‘01’)
ADC1BUF15 — —
ADC1BUF14 — —
ADC1BUF13 — —
ADC1BUF12 — —
ADC1BUF11 — —
ADC1BUF10 — —
ADC1BUF9 — —
ADC1BUF8 — —
ADC1BUF7 — —
ADC1BUF6 — —
ADC1BUF5 — —
ADC1BUF4 — —
ADC1BUF3 — —
ADC1BUF2 Threshold Value Conversion Value
ADC1BUF1 — —
ADC1BUF0 — —
AD1CHITL
15 14 13 12 11 10 9 8
00000000
76543210
00000000
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FIGURE 22-13: INSIDE WINDOW COMPARISON OPERATION
22.7.5.3 Outside Window Comparison
When the Compare Mode bits CM<1:0> are
programmed as '11', the converter compares the
sampled value to see if it falls outside of the threshold
values in the buffer and mirrored channel location.
Again, since the value in the mirrored channel location
is always the greater value of the two thresholds, the
condition is met when either:
Converted Value >Threshold 2
or
Threshold 1 > Converted Value
In these cases, the following occurs:
• The Compare Hit bit (CHHn) for the correspond-
ing channel is set.
• If the converted value is greater than Threshold
2, the CHHn bit for the mirrored channel is also
set. If it is less than Threshold 1, the mirrored
channel bit remains '0'.
• If the Write Mode bits, WM<1:0>
(ADCON5L<3:2>), are programmed to '01':
- If the converted value is above Threshold 2,
the converted value is written to the mirrored
channel address, replacing the upper thresh-
old value.
- If the converted value is below Threshold 1,
the converted value is written to the channel
address, replacing the lower threshold value.
• If WM<1:0> = 10, the converted value is
discarded.
The changes to the result buffer and the Compare Hit
register are shown in Figure 22-15 (over the upper
threshold) and Figure 22-16 (under the lower thresh-
old).
Note that when a Windowed Comparison mode is
selected and channel mirroring is enabled, nothing pre-
vents a conversion from another operation from being
stored in the mirrored channel location. In the previous
examples of windowed operation, if AN10 is included in
a Threshold Detect operation, a conversion on AN10
might be tested against the upper threshold for AN2,
stored in that location. This could result in the threshold
value being overwritten and/or the CHH10 bit being set.
ADC1BUF15 —
ADC1BUF14 —
ADC1BUF13 —
ADC1BUF12 —
ADC1BUF11 —
ADC1BUF10 Threshold 2
ADC1BUF9 —
ADC1BUF8 —
ADC1BUF7 —
ADC1BUF6 —
ADC1BUF5 —
ADC1BUF4 —
ADC1BUF3 —
ADC1BUF2 Threshold 1
ADC1BUF1 —
ADC1BUF0 —
Before Conversion and Comparison
AD1CHITL
15 14 13 12 11 10 9 8
00000000
76543210
00000100
After Conversion and Comparison
Compare Only
(‘10’)
Compare and
Store (‘01’)
ADC1BUF15 — —
ADC1BUF14 — —
ADC1BUF13 — —
ADC1BUF12 — —
ADC1BUF11 — —
ADC1BUF10 Threshold 2 Threshold 2
ADC1BUF9 — —
ADC1BUF8 — —
ADC1BUF7 — —
ADC1BUF6 — —
ADC1BUF5 — —
ADC1BUF4 — —
ADC1BUF3 — —
ADC1BUF2 Threshold 1 Conversion Value
ADC1BUF1 — —
ADC1BUF0 — —
AD1CHITL
15 14 13 12 11 10 9 8
00000000
76543210
00000000
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For this reason, users must always carefully consider
the allocation and use of the upper analog channels
(both external and internal) when using Windowed
Compare modes. Wherever possible, exclude the
upper analog channels for Threshold Detect
operations, and convert and test those channels in a
separate routine.
FIGURE 22-14: OUTSIDE WINDOW COMPARISON OPERATION (OVER THRESHOLD 2)
ADC1BUF15 —
ADC1BUF14 —
ADC1BUF13 —
ADC1BUF12 —
ADC1BUF11 —
ADC1BUF10 Threshold 2
ADC1BUF9 —
ADC1BUF8 —
ADC1BUF7 —
ADC1BUF6 —
ADC1BUF5 —
ADC1BUF4 —
ADC1BUF3 —
ADC1BUF2 Threshold 1
ADC1BUF1 —
ADC1BUF0 —
Before Conversion and Comparison
AD1CHITL
15 14 13 12 11 10 98
00000100
76543210
00000100
After Conversion and Comparison
Compare Only
(‘10’)
Compare and
Store (‘01’)
ADC1BUF15 — —
ADC1BUF14 — —
ADC1BUF13 — —
ADC1BUF12 — —
ADC1BUF11 — —
ADC1BUF10 Threshold 2 Conversion Value
ADC1BUF9 — —
ADC1BUF8 — —
ADC1BUF7 — —
ADC1BUF6 — —
ADC1BUF5 — —
ADC1BUF4 — —
ADC1BUF3 — —
ADC1BUF2 Threshold 1 Threshold 1
ADC1BUF1 — —
ADC1BUF0 — —
AD1CHITL
15 14 13 12 11 10 9 8
00000000
76543210
00000000
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FIGURE 22-15: OUTSIDE WINDOW COMPARISON OPERATION (UNDER THRESHOLD 1)
22.8 Examples
22.8.1 INITIALIZATION
Example 22-1 shows a simple initialization code
example for the A/D module. Operation in Idle mode is
disabled, output data is in unsigned fractional format,
and AVDD and AVSS are used for VR+ and VR-. The
start of sampling, as well as the start of conversion
(conversion trigger), are performed directly in software.
Scanning of inputs is disabled and an interrupt occurs
after every sample/convert sequence (one conversion
result) with only one channel (AN0) being converted.
The A/D conversion clock is TCY/2.
In this particular configuration, all 16 analog input pins
are set up as analog inputs. It is important to note that
with this A/D module, I/O pins are configured for analog
or digital operation at the I/O port with the ANSn Analog
Select registers. The use of these registers is
described in detail in the I/O Port chapter of the specific
device data sheet.
This example shows one method of controlling a
sample/convert sequence by manually setting and
clearing the SAMP bit (ADCON1L<1>). This method,
among others, is more fully discussed in Section 22.4
“Controlling the Sampling Process” and Section
22.5 “Controlling the Conversion Process”.
ADC1BUF15 —
ADC1BUF14 —
ADC1BUF13 —
ADC1BUF12 —
ADC1BUF11 —
ADC1BUF10 Threshold 2
ADC1BUF9 —
ADC1BUF8 —
ADC1BUF7 —
ADC1BUF6 —
ADC1BUF5 —
ADC1BUF4 —
ADC1BUF3 —
ADC1BUF2 Threshold 1
ADC1BUF1 —
ADC1BUF0 —
Before Conversion and Comparison
AD1CHITL
15 14 13 12 11 10 9 8
00000000
76543210
00000100
After Conversion and Comparison
Compare Only
(‘10’)
Compare and
Store (‘01’)
ADC1BUF15 — —
ADC1BUF14 — —
ADC1BUF13 — —
ADC1BUF12 — —
ADC1BUF11 — —
ADC1BUF10 Threshold 2 Threshold 2
ADC1BUF9 — —
ADC1BUF8 — —
ADC1BUF7 — —
ADC1BUF6 — —
ADC1BUF5 — —
ADC1BUF4 — —
ADC1BUF3 — —
ADC1BUF2 Threshold 1 Conversion Value
ADC1BUF1 — —
ADC1BUF0 — —
AD1CHITL
15 14 13 12 11 10 9 8
00000000
76543210
00000000
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EXAMPLE 22-3: A/D INITIALIZATION CODE EXAMPLE
ADCON1H = 0x22; // Configure sample clock source
ADCON1L = 0x00; // and conversion trigger mode.
// Unsigned Fraction format (FORM<1:0>=10),
// Manual conversion trigger (SSRC<3:0>=0000),
// Manual start of sampling (ASAM=0),
// No operation in Idle mode (ADSIDL=1),
// S/H in Sample (SAMP = 1)
ADCON2H = 0; // Configure A/D voltage reference
ADCON2L = 0; // and buffer fill modes.
// Vr+ and Vr- from AVdd and AVss(PVCFG<1:0>=00, NVCFG=0),
// Inputs are not scanned,
// Interrupt after every sample
ADCON3H = 0; // Configure sample time = 1Tad,
ADCON3L = 0; // A/D conversion clock as Tcy
ADCHS0H = 0; // Configure input channels,
ADCHS0L = 0; // S/H+ input is AN0,
// S/H- input is Vr- (AVss).
ADCSS0L = 0; // No inputs are scanned.
ADCSS0H = 0; // No inputs are scanned.
PIR1bits.ADIF = 0; // Clear A/D conversion interrupt.
// Configure A/D interrupt priority bits (ADIP) here, if
// required. Default priority level is high.
PIE1bits.ADIE = 1; // Enable A/D conversion interrupt
ADCON1Hbits.ADON = 1; // Turn on A/D
ADCON1Lbits.SAMP = 1; // Start sampling the input
Delay(); // Ensure the correct sampling time has elapsed
// before starting conversion.
ADCON1Lbits.SAMP = 0; // End A/D sampling and start conversion
// Example code for A/D ISR:
#pragma interrupt _ADC1Interrupt
void _ADC1Interrupt(void)
{
PIR1bits.ADIF = 0;
}
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22.8.2 CONVERSION SEQUENCE
EXAMPLES
The following configuration examples show the A/D
operation in different sampling and buffering configura-
tions. In each example, setting the ASAM bit starts
automatic sampling. A conversion trigger ends
sampling and starts conversion.
22.8.2.1 Sampling and Converting a Single
Channel Multiple Times
In this case Figure 22-16, one A/D input, AN0, will be
sampled and converted. The results are stored in the
ADCBUFn buffer. This process repeats 16 times until
the buffer is full and then the module generates an
interrupt. The entire process will then repeat.
With the ALTS bit clear, only the MUX A inputs are
active. The CH0SAx and CH0NAx bits are specified
(AN0 - VR-) as the inputs to the Sample-and-Hold
channel. All other input selection bits are unused.
FIGURE 22-16: CONVERTING ONE CHANNEL 16 TIMES PER INTERRUPT
Conversion
A/D CLK
SAMP
ADC1BUF0
TSAMP
TCONV
BSF AD1CON1, ASAM
ADC1BUF1
DONE
ADC1BUFE
ADC1BUFF
Analog Input AN0
TSAMP
TCONV
AN0
TSAMP
TCONV
AN0
TSAMP
TCONV
AN0
AD1IF
ASAM
Trigger
Instruction Execution
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EXAMPLE 22-4: CONVERTING A SINGLE CHANNEL 16 TIMES PER INTERRUPT
A/D Configuration:
• Select AN0 for S/H+ Input (CH0SA<4:0> = 00000)
•Select V
R- for S/H- Input (CH0NA<2:0> = 000)
• Configure for No Input Scan (CSCNA = 0)
• Use Only MUX A for Sampling (ALTS = 0)
• Set AD1IF on Every 16th Sample (SMPI<4:0> = 01111)
• Configure Buffers for Single, 16-Word Results (BUFM = 0)
Operational Sequence:
1. Sample MUX A Input AN0; Convert and Write to Buffer 0h.
2. Sample MUX A Input AN0; Convert and Write to Buffer 1h.
3. Sample MUX A Input AN0; Convert and Write to Buffer 2h.
4. Sample MUX A Input AN0; Convert and Write to Buffer 3h.
5. Sample MUX A Input AN0; Convert and Write to Buffer 4h.
6. Sample MUX A Input AN0; Convert and Write to Buffer 5h.
7. Sample MUX A Input AN0; Convert and Write to Buffer 6h.
8. Sample MUX A Input AN0; Convert and Write to Buffer 7h.
9. Sample MUX A Input AN0; Convert and Write to Buffer 8h.
10. Sample MUX A Input AN0; Convert and Write to Buffer 9h.
11. Sample MUX A Input AN0; Convert and Write to Buffer Ah.
12. Sample MUX A Input AN0; Convert and Write to Buffer Bh.
13. Sample MUX A Input AN0; Convert and Write to Buffer Ch.
14. Sample MUX A Input AN0; Convert and Write to Buffer Dh.
15. Sample MUX A Input AN0; Convert and Write to Buffer Eh.
16. Sample MUX A Input AN0; Convert and Write to Buffer Fh.
17. Set AD1IF Flag (and generate interrupt, if enabled).
18. Repeat (1-16) After Return from Interrupt.
Results Stored in Buffer (after 2 cycles):
Buffer
Address
Buffer Contents
at 1st AD1IF Event
Buffer Contents
at 2nd AD1IF Event
ADC1BUF0 AN0, Sample 1 AN0, Sample 17
ADC1BUF1 AN0, Sample 2 AN0, Sample 18
ADC1BUF2 AN0, Sample 3 AN0, Sample 19
ADC1BUF3 AN0, Sample 4 AN0, Sample 20
ADC1BUF4 AN0, Sample 5 AN0, Sample 21
ADC1BUF5 AN0, Sample 6 AN0, Sample 22
ADC1BUF6 AN0, Sample 7 AN0, Sample 23
ADC1BUF7 AN0, Sample 8 AN0, Sample 24
ADC1BUF8 AN0, Sample 9 AN0, Sample 25
ADC1BUF9 AN0, Sample 10 AN0, Sample 26
ADC1BUFA AN0, Sample 11 AN0, Sample 27
ADC1BUFB AN0, Sample 12 AN0, Sample 28
ADC1BUFC AN0, Sample 13 AN0, Sample 29
ADC1BUFD AN0, Sample 14 AN0, Sample 30
ADC1BUFE AN0, Sample 15 AN0, Sample 31
ADC1BUFF AN0, Sample 16 AN0, Sample 32
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22.8.2.2 A/D Conversions While Scanning
Through All Analog Inputs
Figure 22-17 and Example 22-5 illustrate a typical
setup, where all available analog input channels are
sampled and converted. In this instance, 16 analog
inputs are assumed. The set CSCNA bit specifies
scanning of the A/D inputs to the S/H positive input.
Other conditions are similar to those located in Section
Section 22.8.2.1 “Sampling and Converting a
Single Channel Multiple Times”.
Initially, the AN0 input is sampled and converted. The
result is stored in the ADCBUFn buffer. Then, the AN1
input is sampled and converted. This process of scan-
ning the inputs repeats 16 times, until the buffer is full,
and then the module generates an interrupt. The entire
process will then repeat.
FIGURE 22-17: SCANNING ALL 16 INPUTS PER SINGLE INTERRUPT
Conversion
A/D CLK
SAMP
ADC1BUF0
TSAMP
TCONV
BSET AD1CON1, #ASAM
ADC1BUF1
DONE
ADC1BUFE
ADC1BUFF
Analog Input AN0
TSAMP
TCONV
AN1
TSAMP
TCONV
AN14
TSAMP
TCONV
AN15
AD1IF
ASAM
Trigger
Instruction Execution
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EXAMPLE 22-5: SCANNING AND CONVERTING ALL 16 CHANNELS PER SINGLE INTERRUPT
A/D Configuration:
• Select Any Channel for S/H+ Input (CH0SA<4:0> = xxxxx)
•Select V
R- for S/H- Input (CH0NA<2:0> = 000)
• Use Only MUX A for Sampling (ALTS = 0)
• Configure MUX A for Input Scan (CSCNA = 1)
• Include All Analog Channels in Scanning (AD1CSSL = 1111 1111 1111 1111)
• Set AD1IF on Every 16th Sample (SMPI<4:0> = 01111)
• Configure Buffers for Single, 16-Word Results (BUFM = 0)
Operational Sequence:
1. Sample MUX A Input AN0; Convert and Write to Buffer 0h.
2. Sample MUX A Input AN1; Convert and Write to Buffer 1h.
3. Sample MUX A Input AN2; Convert and Write to Buffer 2h.
4. Sample MUX A Input AN3; Convert and Write to Buffer 3h.
5. Sample MUX A Input AN4; Convert and Write to Buffer 4h.
6. Sample MUX A Input AN5; Convert and Write to Buffer 5h.
7. Sample MUX A Input AN6; Convert and Write to Buffer 6h.
8. Sample MUX A Input AN7; Convert and Write to Buffer 7h.
9. Sample MUX A Input AN8; Convert and Write to Buffer 8h.
10. Sample MUX A Input AN9; Convert and Write to Buffer 9h.
11. Sample MUX A Input AN10; Convert and Write to Buffer Ah.
12. Sample MUX A Input AN11; Convert and Write to Buffer Bh.
13. Sample MUX A Input AN12; Convert and Write to Buffer Ch.
14. Sample MUX A Input AN13; Convert and Write to Buffer Dh.
15. Sample MUX A Input AN14; Convert and Write to Buffer Eh.
16. Sample MUX A Input AN15; Convert and Write to Buffer Fh.
17. Set AD1IF Flag (and generate interrupt, if enabled).
18. Repeat (1-16) after Return from Interrupt.
Results Stored in Buffer (after 2 cycles):
Buffer
Address
Buffer Contents
at 1st AD1IF Event
Buffer Contents
at 2nd AD1IF Event
ADC1BUF0 Sample 1 (AN0, Sample 1) Sample 17 (AN0, Sample 2)
ADC1BUF1 Sample 2 (AN1, Sample 1) Sample 18 (AN1, Sample 2)
ADC1BUF2 Sample 3 (AN2, Sample 1) Sample 19 (AN2, Sample 2)
ADC1BUF3 Sample 4 (AN3, Sample 1) Sample 20 (AN3, Sample 2)
ADC1BUF4 Sample 5 (AN4, Sample 1) Sample 21 (AN4, Sample 2)
ADC1BUF5 Sample 6 (AN5, Sample 1) Sample 22 (AN5, Sample 2)
ADC1BUF6 Sample 7 (AN6, Sample 1) Sample 23 (AN6, Sample 2)
ADC1BUF7 Sample 8 (AN7, Sample 1) Sample 24 (AN7, Sample 2)
ADC1BUF8 Sample 9 (AN8, Sample 1) Sample 25 (AN8, Sample 2)
ADC1BUF9 Sample 10 (AN9, Sample 1) Sample 26 (AN9, Sample 2)
ADC1BUF10 Sample 11 (AN10, Sample 1) Sample 27 (AN10, Sample 2)
ADC1BUF11 Sample 12 (AN11, Sample 1) Sample 28 (AN11, Sample 2)
ADC1BUF12 Sample 13 (AN12, Sample 1) Sample 29 (AN12, Sample 2)
ADC1BUF13 Sample 14 (AN13, Sample 1) Sample 30 (AN13, Sample 2)
ADC1BUF14 Sample 15 (AN14, Sample 1) Sample 31 (AN14, Sample 2)
ADC1BUF15 Sample 16 (AN15, Sample 1) Sample 32 (AN15, Sample 2)
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22.8.3 USING DUAL BUFFERS
Figure 22-18 and Example 22-6 demonstrate using
dual buffers and alternating the buffer fill.
Setting the BUFM bit enables dual buffers. In this
example, an interrupt is generated after each sample.
The BUFM setting does not affect other operational
parameters. First, the conversion sequence starts
filling the buffer at ADCBUF0. After the first interrupt
occurs, the buffer begins to fill at ADCBUF8. The BUFS
status bit is toggled after each interrupt.
FIGURE 22-18: CONVERTING A SINGLE CHANNEL, ONCE PER INTERRUPT, USING DUAL,
8-WORD BUFFERS
A/D CLK
SAMP
ADC1BUF0
BSET AD1CON1, #ASAM
Analog Input AN3
TSAMP
AD1IF
ADC1BUF8
AN3
TSAMP
AN3
TSAMP
BUFS
Conversion
Trigger
T
CONV
T
CONV
T
CONV
T
CONV
T
CONV
T
CONV
T
CONV
T
CONV
T
CONV
T
CONV
BCLR IFS0, #AD1IF BCLR IFS0, #AD1IF
T
CONV
T
CONV
Instruction Execution
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EXAMPLE 22-6: CONVERTING A SINGLE CHANNEL, ONCE PER INTERRUPT, DUAL BUFFER
MODE
22.8.3.1 Using Alternating MUX A and MUX
B Input Selections
Figure 22-19 and Example 22-7 demonstrate alternate
sampling of the inputs assigned to MUX A and MUX B.
Setting the ALTS bit enables alternating input selec-
tions. The first sample uses the MUX A inputs specified
by the CH0SAx and CH0NAx bits. The next sample
uses the MUX B inputs, specified by the CH0SBx and
CH0NBx bits.
This example also demonstrates use of the dual,
8-word buffers. An interrupt occurs after every 8th
sample, resulting in filling eight words into the buffer on
each interrupt.
A/D Configuration:
• Select AN3 for S/H+ Input (CH0SA<4:0> = 00011)
•Select V
R- for S/H- Input (CH0NA<2:0> = 000)
• Configure for No Input Scan (CSCNA = 0)
• Use Only MUX A for Sampling (ALTS = 0)
• Set AD1IF on Every Sample (SMPI<4:0> = 00000)
• Configure Buffer as Dual, 8-Word Segments (BUFM = 1)
Operational Sequence:
1. Sample MUX A Input, AN3; Convert and Write to Buffer 0h.
2. Set AD1IF Flag (and generate interrupt, if enabled); Write Access Automatically
Switches to Alternate Buffer.
3. Sample MUX A Input, AN3; Convert and Write to Buffer 8h.
4. Set AD1IF Flag (and generate interrupt, if enabled); Write Access Automatically
Switches to Alternate Buffer.
5. Repeat (1-4).
Results Stored in Buffer (after 2 cycles):
Buffer
Address
Buffer Contents
at 1st AD1IF Event
Buffer Contents
at 2nd AD1IF Event
ADC1BUF0 Sample 1 (AN3, Sample 1) (undefined)
ADC1BUF1 (undefined) (undefined)
ADC1BUF2 (undefined) (undefined)
ADC1BUF3 (undefined) (undefined)
ADC1BUF4 (undefined) (undefined)
ADC1BUF5 (undefined) (undefined)
ADC1BUF6 (undefined) (undefined)
ADC1BUF7 (undefined) (undefined)
ADC1BUF8 (undefined) Sample 2 (AN3, Sample 2)
ADC1BUF9 (undefined) (undefined)
ADC1BUFA (undefined) (undefined)
ADC1BUFB (undefined) (undefined)
ADC1BUFC (undefined) (undefined)
ADC1BUFD (undefined) (undefined)
ADC1BUFE (undefined) (undefined)
ADC1BUFF (undefined) (undefined)
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FIGURE 22-19: CONVERTING TWO INPUTS USING ALTERNATING INPUT SELECTIONS
A/D CLK
SAMP
ADC1BUF0
ADC1BUF1
DONE
ADC1BUF2
ADC1BUF3
Analog AN1
TSAMP
AD1IF
T
CONV
ADC1BUF4
ADC1BUF5
ADC1BUF6
ADC1BUF7
AN15
TSAMP
T
CONV
ASAM
BUFS
AN1
TSAMP
T
CONV
AN15
TSAMP
T
CONV
ADC1BUF8
ADC1BUF9
ADC1BUFA
ADC1BUFB
T
CONV
TSAMP
AN15
Input
Conversion
Trigger
Cleared by Software
Cleared
in Software
T
CONV
T
CONV
T
CONV
T
CONV
T
CONV
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EXAMPLE 22-7: CONVERTING TWO INPUTS BY ALTERNATING MUX A AND MUX B
A/D Configuration:
• Select AN1 for MUX A S/H+ Input (CH0SA<4:0> = 00001)
•Select V
R- for MUX A S/H- Input (CH0NA<2:0> = 000)
• Configure for No Input Scan (CSCNA = 0)
• Select AN15 for MUX B S/H+ Input (CH0SB<4:0> = 11111)
•Select V
R- for MUX B S/H- Input (CH0NB<2:0> = 000)
• Alternate MUX A and MUX B for Sampling (ALTS = 1)
• Set AD1IF on Every 8th Sample (SMPI<4:0> = 00111)
• Configure Buffer as Two, 8-Word Segments (BUFM = 1)
Operational Sequence:
1. Sample MUX A Input AN1; Convert and Write to Buffer 0h.
2. Sample MUX B Input AN15; Convert and Write to Buffer 1h.
3. Sample MUX A Input AN1; Convert and Write to Buffer 2h.
4. Sample MUX B Input AN15; Convert and Write to Buffer 3h.
5. Sample MUX A Input AN1; Convert and Write to Buffer 4h.
6. Sample MUX B Input AN15; Convert and Write to Buffer 5h.
7. Sample MUX A Input AN1; Convert and Write to Buffer 6h.
8. Sample MUX B Input AN15; Convert and Write to Buffer 7h.
9. Set AD1IF Flag (and generate interrupt, if enabled); Write Access Automatically
Switches to Alternate Buffer.
10. Repeat (1-9); Resume Writing to Buffer with Buffer 8h (first address of alternate buffer).
Results Stored in Buffer (after 2 cycles):
Buffer
Address
Buffer Contents
at 1st AD1IF Event
Buffer Contents
at 2nd AD1IF Event
ADC1BUF0 Sample 1 (AN1, Sample 1) (undefined)
ADC1BUF1 Sample 2 (AN15, Sample 1) (undefined)
ADC1BUF2 Sample 3 (AN1, Sample 2) (undefined)
ADC1BUF3 Sample 4 (AN15, Sample 2) (undefined)
ADC1BUF4 Sample 5 (AN1, Sample 3) (undefined)
ADC1BUF5 Sample 6 (AN15, Sample 3) (undefined)
ADC1BUF6 Sample 7 (AN1, Sample 4) (undefined)
ADC1BUF7 Sample 8 (AN15, Sample 4) (undefined)
ADC1BUF8 (undefined) Sample 9 (AN1, Sample 5)
ADC1BUF9 (undefined) Sample 10 (AN15, Sample 5)
ADC1BUFA (undefined) Sample 11 (AN1, Sample 6)
ADC1BUFB (undefined) Sample 12 (AN15, Sample 6)
ADC1BUFC (undefined) Sample 13 (AN1, Sample 7)
ADC1BUFD (undefined) Sample 14 (AN15, Sample 7)
ADC1BUFE (undefined) Sample 15 (AN1, Sample 8)
ADC1BUFF (undefined) Sample 16 (AN15, Sample 8)
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22.9 A/D Sampling Requirements
The Analog Input model of the 12-bit A/D Converter is
shown in Figure 22-20. The total sampling time for the
A/D is a function of the holding capacitor charge time.
For the A/D Converter to meet its specified accuracy,
the charge holding capacitor (CHOLD) must be allowed
to fully charge to the voltage level on the analog input
pin. The source impedance (RS), the interconnect
impedance (RIC) and the internal sampling switch
(RSS) impedance combine to directly affect the time
required to charge CHOLD. The combined impedance
of the analog sources must, therefore, be small enough
to fully charge the holding capacitor within the chosen
sample time. To minimize the effects of pin leakage
currents on the accuracy of the A/D Converter, the
maximum recommended source impedance, RS, is 2.5
k. After the analog input channel is selected (changed),
this sampling function must be completed prior to
starting the conversion. The internal holding capacitor
will be in a discharged state prior to each sample
operation.
At least 1 TAD time period should be allowed between
conversions for the sample time. For more details, see
Section 31.0 “Electrical Characteristics”.
FIGURE 22-20: 12-BIT A/D CONVERTER ANALOG INPUT MODEL
22.10 Transfer Functions
The transfer functions of the A/D Converter, in 12-bit
and 10-bit resolution, are shown in Figure 22-21 and
Figure 22-22, respectively. In both cases, the differ-
ence of the input voltages, (VINH - VINL), is compared
to the reference, ((VR+) - (VR-)).
For the 12-bit transfer function:
• The first code transition occurs when the input
voltage is ((VR+) - (VR-))/4096 or 1.0 LSb.
•The '0000 0000 0001' code is centered at VR-
+ (1.5 * ((VR+) - (VR-)) / 4096).
•The '0010 0000 0000' code is centered at
VREFL + (2048.5 * ((VR+) - (VR-)) /4096).
• An input voltage less than VR- + (((VR-) - (VR-)) /
4096) converts as '0000 0000 0000'.
• An input voltage greater than (VR-) + (4096
((VR+) - (VR-))/4096) converts as '1111 1111
1111'.
CPIN
VA
Rs ANx
ILEAKAGE
RIC 250Sampling
Switch
RSS
CHOLD
VSS
= 4.4 pF
500 nA
Legend: CPIN
VT
ILEAKAGE
RIC
RSS
CHOLD
= Input Capacitance
= Threshold Voltage
= Leakage Current at the Pin due to
= Interconnect Resistance
= Sampling Switch Resistance
= Sample/Hold Capacitance (from DAC)
Various Junctions
Note: CPIN value depends on device package and is not tested. The effect of the CPIN is negligible if Rs 5 k.
RSS 3 k
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FIGURE 22-21: 12-BIT A/D TRANSFER FUNCTION
For the 10-bit transfer function (when 10-bit resolution
is available):
• The first code transition occurs when the input
voltage is ((VR+) - (VR-))/1024 or 1.0 LSb.
•The '00 0000 0001' code is centered at VR- +
(1.5 * (((VR+) - (VR-)) / 1024).
•The '10 0000 0000' code is centered at VREFL
+ (512.5 * (((VR+) - (VR-)) /1024).
• An input voltage less than VR- + (((VR-) - (VR-)) /
1024) converts as '00 0000 0000'.
• An input voltage greater than (VR-) + ((1023
(VR+)) - (VR-))/1024) converts as '11 1111
1111'.
0010 0000 0001 (2049)
0010 0000 0010 (2050)
0010 0000 0011 (2051)
0001 1111 1101 (2045)
0001 1111 1110 (2046)
0001 1111 1111 (2047)
1111 1111 1110 (4094)
1111 1111 1111 (4095)
0000 0000 0000 (0)
0000 0000 0001 (1)
Output Code
0010 0000 0000 (2048)
(VINH – VINL)
VR-
VR+ – VR-
4096
2048 * (VR+ – VR-)
4096
VR+
VR- +
VR- +
4095 * (VR + – VR-)
4096
VR- +
0
(Binary (Decimal))
Voltage Level
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FIGURE 22-22: 10-BIT A/D TRANSFER FUNCTION
22.11 Operation During Sleep and Idle
Modes
Sleep and Idle modes are useful for minimizing conver-
sion noise because the digital activity of the CPU,
buses and other peripherals is minimized.
22.11.1 CPU SLEEP MODE WITHOUT RC
A/D CLOCK
When the device enters Sleep mode, all clock sources
to the module are shut down and stay at logic '0'.
If Sleep occurs in the middle of a conversion, the
conversion is aborted unless the A/D is clocked from its
internal RC clock generator. The converter will not
resume a partially completed conversion on exiting
from Sleep mode.
Register contents are not affected by the device
entering or leaving Sleep mode.
22.11.2 CPU SLEEP MODE WITH RC A/D
CLOCK
The A/D module can operate during Sleep mode if the
A/D clock source is set to the internal A/D RC oscillator
(ADRC = 1). This eliminates digital switching noise
from the conversion. When the conversion is
completed, the DONE bit will be set and the result is
loaded into the A/D Result Buffer n, ADCBUFn.
If the A/D interrupt is enabled (ADIE = 1), the device will
wake-up from Sleep when the A/D interrupt occurs.
Program execution will resume at the A/D Interrupt
Service Routine (ISR). After the ISR completes execu-
tion will continue from the instruction after the Sleep
instruction that placed the device in Sleep mode.
If the A/D interrupt is not enabled, the A/D module will
then be turned off, although the ADON bit will remain
set.
10 0000 0001 (513)
10 0000 0010 (514)
10 0000 0011 (515)
01 1111 1101 (509)
01 1111 1110 (510)
01 1111 1111 (511)
11 1111 1110 (1022)
11 1111 1111 (1023)
00 0000 0000 (0)
00 0000 0001 (1)
Output Code
10 0000 0000 (512)
(VINH – VINL)
VR-
VR+ – VR-
1024
512 * (VR+ – VR-)
1024
VR+
VR- +
VR- +
1023 * (VR+ – VR-)
1024
VR- +
0
(Binary (Decimal))
Voltage Level
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To minimize the effects of digital noise on the A/D
module operation, the user should select a conversion
trigger source that ensures the A/D conversion will take
place in Sleep mode. The automatic conversion trigger
option can be used for sampling and conversion in
Sleep (SSRC<3:0> = 0111). To use the automatic
conversion option, the ADON bit should be set in the
instruction prior to the SLEEP instruction.
22.11.3 A/D OPERATION DURING CPU IDLE
MODE
The ADSIDL bit (ADCON1H<5>) determines whether
the module stops or continues operation on Idle. If
ADSIDL = 0, the module will continue normal operation
when the device enters Idle mode. If the A/D interrupt
is enabled (ADIE = 1), the device will wake-up from Idle
mode when the A/D interrupt occurs. Program execu-
tion will resume at the A/D Interrupt Service Routine
(ISR). After the ISR completes execution will continue
from the instruction after the Sleep instruction that
placed the device in Idle mode.
If ADSIDL = 1, the module will stop in Idle. If the device
enters Idle mode in the middle of a conversion, the
conversion is aborted. The converter will not resume a
partially completed conversion on exiting from Idle
mode.
22.11.4 PERIPHERAL MODULE DISABLE
(PMD) REGISTER
The Peripheral Module Disable (PMD) registers
provide a method to disable the A/D module by stop-
ping all clock sources supplied to that module. When a
peripheral is disabled via the appropriate PMDx control
bit, the peripheral is in a minimum power consumption
state. The control and status registers associated with
the peripheral will also be disabled, so writes to those
registers will have no effect and read values will be
invalid. The A/D module is enabled only when the
ADCMD bit in the PMD3 register is cleared.
22.12 Design Tips
Question 1: How can I optimize the system perfor-
mance of the A/D Converter?
Answer: There are three main things to consider in
optimizing A/D performance:
1. Make sure you are meeting all of the timing
specifications. If you are turning the module off
and on, there is a minimum delay you must wait
before taking a sample. If you are changing
input channels, there is a minimum delay you
must wait for this as well, and finally, there is
TAD, which is the time selected for each bit
conversion. This is selected in AD1CON3 and
should be within a certain range, as specified in
Section 31.0 “Electrical Characteristics”. If
TAD is too short, the result may not be fully con-
verted before the con- version is terminated, and
if TAD is made too long, the voltage on the sam-
pling capacitor can decay before the conversion
is complete. These timing specifications are
provided in the “Electrical Characteristics”
section of the device data sheets.
2. Often, the source impedance of the analog
signal is high (greater than 2.5 k), so the
current drawn from the source by leakage, and
to charge the sample capacitor, can affect
accuracy. If the input signal does not change too
quickly, try putting a 0.1 uF capacitor on the
analog input. This capacitor will charge to the
analog voltage being sampled and supply the
instantaneous current needed to charge the
internal holding capacitor.
3. Put the device into Sleep mode before the start
of the A/D conversion. The RC clock source
selection is required for conversions in Sleep
mode. This technique increases accuracy,
because digital noise from the CPU and other
peripherals is minimized.
Question 2: Do you know of a good reference on
A/D Converters?
Answer: A good reference for understanding A/D
conversions is the “Analog-Digital Conversion
Handbook third edition, published by Prentice Hall
(ISBN 0-13-03-2848-0).
Question 3: My combination of channels/samples
and samples/interrupt is greater than the size of the
buffer. What will happen to the buffer?
Answer: This configuration is not recommended. The
buffer will contain unknown results.
22.13 Related Application Notes
This section lists application notes that are related to
this section of the data sheet. These application notes
may not be written specifically for the PIC18F device
family, but the concepts are pertinent and could be
used with modification and possible limitations. The
current application notes related to the 12-Bit A/D
Converter with Threshold Detect module are:
AN546, Using the Analog-to-Digital (A/D) Converter
(DS00546)
AN557, Four-Channel Digital Voltmeter with Display
and Keyboard (DS00557)
AN693, Understanding A/D Converter Performance
Specifications (DS00693)
Note: For the A/D module to operate in Sleep,
the A/D clock source must be set to RC
(ADRC = 1).
Note: Please visit the Microchip web site
(www.microchip.com) for additional
application notes and code examples for
the PIC18F family of devices.
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23.0 COMPARATOR MODULE
The analog comparator module contains three compar-
ators that can be independently configured in a variety
of ways. The inputs can be selected from the analog
inputs and two internal voltage references. The digital
outputs are available at the pin level, via PPS-Lite, and
can also be read through the control register. Multiple
output and interrupt event generations are also avail-
able. A generic single comparator from the module is
shown in Figure 23-1.
Key features of the module includes:
• Independent comparator control
• Programmable input configuration
• Output to both pin and register levels
• Programmable output polarity
• Independent interrupt generation for each
comparator with configurable interrupt-on-change
23.1 Registers
The CMxCON registers (CM1CON, CM2CON and
CM3CON) select the input and output configuration for
each comparator, as well as the settings for interrupt
generation (see Register 23-1).
The CMSTAT register (Register 23-2) provides the out-
put results of the comparators. The bits in this register
are read-only.
FIGURE 23-1: COMPARATOR SIMPLIFIED BLOCK DIAGRAM
Cx
VIN-
VIN+
COE
CxOUT
0
1
2
0
1
CCH<1:0>
CxINB
CxINC
C2INB/C2IND(1)
CxINA
CVREF
CON
Interrupt
Logic
EVPOL<1:0>
CxOUT
(CMSTAT<2:0>)
CMPxIF
CPOL
Polarity
Logic
CREF
3
VBG
Note 1: Comparator 1 and Comparator 3 use C2INB as an input to the inverted terminal. Comparator 2 uses C2IND as an
input to the inverted terminal.
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REGISTER 23-1: CMxCON: COMPARATOR CONTROL x REGISTER
R/W-0 R/W-0 R/W-0 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
CON COE CPOL EVPOL1 EVPOL0 CREF CCH1 CCH0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CON: Comparator Enable bit
1 = Comparator is enabled
0 = Comparator is disabled
bit 6 COE: Comparator Output Enable bit
1 = Comparator output is present on the CxOUT pin
0 = Comparator output is internal only
bit 5 CPOL: Comparator Output Polarity Select bit
1 = Comparator output is inverted
0 = Comparator output is not inverted
bit 4-3 EVPOL<1:0>: Interrupt Polarity Select bits
11 = Interrupt generation on any change of the output(1)
10 = Interrupt generation only on high-to-low transition of the output
01 = Interrupt generation only on low-to-high transition of the output
00 = Interrupt generation is disabled
bit 2 CREF: Comparator Reference Select bit (non-inverting input)
1 = Non-inverting input connects to internal CVREF voltage
0 = Non-inverting input connects to CxINA pin
bit 1-0 CCH<1:0>: Comparator Channel Select bits
11 = Inverting input of comparator connects to VBG
10 = Inverting input of comparator connects to CxINB pin
01 = Inverting input of comparator connects to CxINC pin
00 = Inverting input of comparator connects to C2INB pin(2)
Note 1: The CMPxIF is automatically set any time this mode is selected and must be cleared by the application
after the initial configuration.
2: Comparator 1 and Comparator 3 use C2INB as an input to the inverting terminal. Comparator 2 uses
C2INB as an input to the inverted terminal.
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REGISTER 23-2: CMSTAT: COMPARATOR STATUS REGISTER
U-0 U-0 U-0 U-0 U-0 R-x R-x R-x
— — — — — C3OUT C2OUT C1OUT
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-3 Unimplemented: Read as ‘0’
bit 2-0 C3OUT:C1OUT: Comparator x Status bits
If CPOL (CMxCON<5>)= 0 (non-inverted polarity):
1 = Comparator x’s VIN+ > VIN-
0 = Comparator x’s VIN+ < VIN-
CPOL = 1 (inverted polarity):
1 = Comparator x’s VIN+ < VIN-
0 = Comparator x’s VIN+ > VIN-
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23.2 Comparator Operation
A single comparator is shown in Figure 23-2, along with
the relationship between the analog input levels and
the digital output. When the analog input at VIN+ is less
than the analog input, VIN-, the output of the compara-
tor is a digital low level. When the analog input at VIN+
is greater than the analog input, VIN-, the output of the
comparator is a digital high level. The shaded areas of
the output of the comparator in Figure 23-2 represent
the uncertainty due to input offsets and response time.
FIGURE 23-2: SINGLE COMPARATOR
23.3 Comparator Response Time
Response time is the minimum time, after selecting a
new reference voltage or input source, before the com-
parator output has a valid level. The response time of
the comparator differs from the settling time of the volt-
age reference. Therefore, both of these times must be
considered when determining the total response to a
comparator input change. Otherwise, the maximum
delay of the comparators should be used (see
Section 31.0 “Electrical Characteristics”).
23.4 Analog Input Connection
Considerations
A simplified circuit for an analog input is shown in
Figure 23-3. Since the analog pins are connected to a
digital output, they have reverse biased diodes to VDD
and VSS. The analog input, therefore, must be between
VSS and VDD. If the input voltage deviates from this
range by more than 0.6V in either direction, one of the
diodes is forward biased and a latch-up condition may
occur.
A maximum source impedance of 10 k is
recommended for the analog sources. Any external
component connected to an analog input pin, such as
a capacitor or a Zener diode, should have very little
leakage current.
FIGURE 23-3: COMPARATOR ANALOG INPUT MODEL
Output
VIN-
VIN+
VIN+
VIN-
+
–
Output
VA
RS
AIN
CPIN
5 pF
VDD
RIC
ILEAKAGE
±100 nA
VSS
Legend: CPIN = Input Capacitance
VT= Threshold Voltage
ILEAKAGE = Leakage Current at the pin due to various junctions
RIC = Interconnect Resistance
RS= Source Impedance
VA = Analog Voltage
Comparator
Input
<10 k
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23.5 Comparator Control and
Configuration
Each comparator has up to eight possible combina-
tions of inputs: up to four external analog inputs and
one of two internal voltage references.
All of the comparators allow a selection of the signal
from pin, CxINA, or the voltage from the Comparator
Reference (CVREF) on the non-inverting channel. This
is compared to either CxINB, CxINC, C2IND or the
microcontroller’s fixed internal reference voltage (VBG,
1.2V nominal) on the inverting channel. The compara-
tor inputs and outputs are tied to fixed I/O pins, defined
in Table 23-1. The available comparator configurations
and their corresponding bit settings are shown in
Figure 23-4.
TABLE 23-1: COMPARATOR INPUTS AND
OUTPUTS
23.5.1 COMPARATOR ENABLE AND
INPUT SELECTION
Setting the CON bit of the CMxCON register
(CMxCON<7>) enables the comparator for operation.
Clearing the CON bit disables the comparator, resulting
in minimum current consumption.
The CCH<1:0> bits in the CMxCON register
(CMxCON<1:0>) direct either one of three analog input
pins, or the Internal Reference Voltage (VBG), to the
comparator, VIN-. Depending on the comparator oper-
ating mode, either an external or internal voltage
reference may be used.
The analog signal present at VIN- is compared to the
signal at VIN+ and the digital output of the comparator
is adjusted accordingly.
The external reference is used when CREF = 0
(CMxCON<2>) and VIN+ is connected to the CxINA
pin. When external voltage references are used, the
comparator module can be configured to have the ref-
erence sources externally. The reference signal must
be between VSS and VDD and can be applied to either
pin of the comparator.
The comparator module also allows the selection of an
internally generated voltage reference from the Compar-
ator Voltage Reference (CVREF) module. This module is
described in more detail in Section 24.0 “Comparator
Voltage Reference Module”. The reference from the
comparator voltage reference module is only available
when CREF = 1. In this mode, the internal voltage
reference is applied to the comparator’s VIN+ pin.
23.5.2 COMPARATOR ENABLE AND
OUTPUT SELECTION
The comparator outputs are read through the CMSTAT
register. The CMSTAT<0> bit reads the Comparator 1
output, CMSTAT<2> reads the Comparator 2 output
and the CMSTAT<3> bit reads the Comparator 3 output
These bits are read-only.
The comparator outputs may also be directly output to
the RPn I/O pins by setting the COE bit (CMxCON<6>).
When enabled, multiplexers in the output path of the
pins switch to the output of the comparator. While in this
mode, the respective TRISx bits still function as the
digital output enable bits for the RPn I/O pins.
Comparator Input or Output I/O Pin(†)
1
C1INA (VIN+) RA5/RF6
C1INB (VIN-) RF5
C1INC (VIN-) RH6(2)
C2INB(VIN-) RF2
CVREF (VIN+) RF5
C1OUT RPn(1)
2
C2INA (VIN+) RA5
C2INB (VIN-) RF2
C2INC (VIN-) RH4(2)
C2IND (VIN-) RH5(2)
CVREF (VIN+) RF5
C2OUT RPn(1)
3
C3INA (VIN+) RA5/RG2
C3INB (VIN-) RG3
C2INB (VIN-) RF2
C3INC (VIN-) RG4
CVREF (VIN+) RF5
C3OUT RPn(1)
† The I/O pin is dependent on package type.
Note 1: These pins are remappable I/Os.
2: These pins are not available on 64-pin
devices.
Note: The comparator input pin selected by
CCH<1:0> must be configured as an input
by setting both the corresponding TRISx bit
and the corresponding ANSELx bit in the
ANCONx register.
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By default, the comparator’s output is at logic high
whenever the voltage on VIN+ is greater than on VIN-.
The polarity of the comparator outputs can be inverted
using the CPOL bit (CMxCON<5>).
The uncertainty of each of the comparators is related to
the input offset voltage and the response time given in
the specifications, as discussed in Section 23.2
“Comparator Operation”.
FIGURE 23-4: COMPARATOR CONFIGURATIONS
Cx
VIN-
VIN+Off (Read as ‘0’)
Comparator Off
CON = 0, CREF = x, CCH<1:0> = xx COE
Cx
VIN-
VIN+
COE
Comparator CxINB > CxINA Compare
CON = 1, CREF = 0, CCH<1:0> = 00
CxINB
CxINA Cx
VIN-
VIN+
COE
Comparator CxINC > CxINA Compare
CON = 1, CREF = 0, CCH<1:0> = 01
CxINC
CxINA
Cx
VIN-
VIN+
COE
Comparator C2IND/C2INB > CxINA Compare
CON = 1, CREF = 0, CCH<1:0> = 10
C2INB
CxINA
Cx
VIN-
VIN+
COE
Comparator VBG > CxINA Compare
CON = 1, CREF = 0, CCH<1:0> = 11
VBG
CxINA
Cx
VIN-
VIN+
COE
Comparator CxINB > CVREF Compare
CON = 1, CREF = 1, CCH<1:0> = 00
CxINB
CVREF Cx
VIN-
VIN+
COE
Comparator CxINC > CVREF Compare
CON = 1, CREF = 1, CCH<1:0> = 01
CxINC
CVREF
Cx
VIN-
VIN+
COE
Comparator C2IND/C2INB > CVREF Compare
CON = 1, CREF = 1, CCH<1:0> = 10
CVREF
Cx
VIN-
VIN+
COE
Pin
Comparator VBG > CVREF Compare
CON = 1, CREF = 1, CCH<1:0> = 11
VBG
CVREF CxOUT
Note 1: VBG is the Internal Reference Voltage (see Table 31-10).
Pin
CxOUT
Pin
CxOUT
Pin
CxOUT
Pin
CxOUT
Pin
CxOUT
Pin
CxOUT
Pin
CxOUT
Pin
CxOUT
C2IND/
C2INB
C2IND/
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23.6 Comparator Interrupts
The comparator interrupt flag is set whenever any of
the following occurs:
• Low-to-high transition of the comparator output
• High-to-low transition of the comparator output
• Any change in the comparator output
The comparator interrupt selection is done by the
EVPOL<1:0> bits in the CMxCON register
(CMxCON<4:3>).
In order to provide maximum flexibility, the output of the
comparator may be inverted using the CPOL bit in the
CMxCON register (CMxCON<5>). This is functionally
identical to reversing the inverting and non-inverting
inputs of the comparator for a particular mode.
An interrupt is generated on the low-to-high or high-to-
low transition of the comparator output. This mode of
interrupt generation is dependent on EVPOL<1:0> in
the CMxCON register. When EVPOL<1:0> = 01 or 10,
the interrupt is generated on a low-to-high or high-to-
low transition of the comparator output. Once the
interrupt is generated, it is required to clear the interrupt
flag by software.
When EVPOL<1:0> = 11, the comparator interrupt flag
is set whenever there is a change in the output value of
either comparator. Software will need to maintain
information about the status of the output bits, as read
from CMSTAT<2:0>, to determine the actual change
that occurred.
The CMPxIF<2:0> (PIR6<2:0>) bits are the Compara-
tor Interrupt Flags. The CMPxIF bits must be reset by
clearing them. Since it is also possible to write a ‘1’ to
this register, a simulated interrupt may be initiated.
Table 23-2 shows the interrupt generation with respect
to comparator input voltages and EVPOL bit settings.
Both the CMPxIE bits (PIE6<2:0>) and the PEIE bit
(INTCON<6>) must be set to enable the interrupt. In
addition, the GIE bit (INTCON<7>) must also be set. If
any of these bits are clear, the interrupt is not enabled,
though the CMPxIF bits will still be set if an interrupt
condition occurs.
A simplified diagram of the interrupt section is shown in
Figure 23-3.
TABLE 23-2: COMPARATOR INTERRUPT GENERATION
Note: CMPxIF will not be set when
EVPOL<1:0> = 00.
CPOL EVPOL<1:0> Comparator
Input Change CxOUT Transition Interrupt
Generated
0
00 VIN+ > VIN- Low-to-High No
VIN+ < VIN-High-to-Low No
01 VIN+ > VIN- Low-to-High Yes
VIN+ < VIN-High-to-Low No
10 VIN+ > VIN- Low-to-High No
VIN+ < VIN-High-to-Low Yes
11 VIN+ > VIN- Low-to-High Yes
VIN+ < VIN-High-to-Low Yes
1
00 VIN+ > VIN-High-to-Low No
VIN+ < VIN- Low-to-High No
01 VIN+ > VIN-High-to-Low No
VIN+ < VIN- Low-to-High Yes
10 VIN+ > VIN-High-to-Low Yes
VIN+ < VIN- Low-to-High No
11 VIN+ > VIN-High-to-Low Yes
VIN+ < VIN- Low-to-High Yes
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23.7 Comparator Operation
During Sleep
When a comparator is active and the device is placed
in Sleep mode, the comparator remains active and the
interrupt is functional, if enabled. This interrupt will
wake-up the device from Sleep mode when enabled.
Each operational comparator will consume additional
current.
To minimize power consumption while in Sleep mode,
turn off the comparators (CON = 0) before entering
Sleep. If the device wakes up from Sleep, the contents
of the CMxCON register are not affected.
23.8 Effects of a Reset
A device Reset forces the CMxCON registers to their
Reset state. This forces both comparators and the
voltage reference to the OFF state.
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24.0 COMPARATOR VOLTAGE
REFERENCE MODULE
The comparator voltage reference is a 32-tap resistor
ladder network that provides a selectable reference
voltage. Although its primary purpose is to provide a
reference for the analog comparators, it may also be
used independently of them.
A block diagram of the module is shown in Figure 24-1.
The resistor ladder is segmented to provide a range of
CVREF values and has a power-down function to
conserve power when the reference is not being used.
The module’s supply reference can be provided from
either device VDD/VSS or an external voltage reference.
24.1 Configuring the Comparator
Voltage Reference
The comparator voltage reference module is controlled
through the CVRCONH register (Register 24-1). The
comparator voltage reference provides a range of
output voltage with 32 levels.
The CVR<4:0> selection bits (CVRCONH<4:0>) offer a
range of output voltages. Equation 24-1 shows how the
comparator voltage reference is computed.
EQUATION 24-1:
The comparator voltage reference supply can come
from either VDD and VSS, or the external VREF+ and
VREF- that are multiplexed with RA3 and RA2. The
voltage source is selected by the CVRPSS<1:0> bits
(CVRCONL<5:4>).
The settling time of the comparator voltage reference
must be considered when changing the CVREF out-
put (see Table 31-10 in Section 31.0 “Electrical
Characteristics”).
If CVRSS = 1:
CVREF = VREF- + • (VREF+ – VREF-)
CVR<4:0>
32
()
If CVRSS = 0:
CVREF = AVSS + • (AVDD – AVSS)
CVR<4:0>
32
()
REGISTER 24-1: CVRCONH: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER HIGH
U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— — — CVR4 CVR3 CVR2 CVR1 CVR0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘0’
bit 4-0 CVR<4:0>: Comparator VREF Value Selection 0 CVR<4:0> 31 bits
CVREF = VNEGSRC + (CVR<4:0>/32) • (VPOSSRC – VNEGSRC)
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FIGURE 24-1: COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
REGISTER 24-2: CVRCONL: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER LOW
R/W-0 R/W-0 R/W-0 R/W-0 U-0 U-0 U-0 R/W-0
CVREN CVROE CVRPSS1 CVRPSS0 — — — CVRNSS
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CVREN: Comparator Voltage Reference Enable bit
1 = CVREF circuit is powered on
0 = CVREF circuit is powered down
bit 6 CVROE: Comparator VREF Output Enable bit
1 = CVREF voltage level is output on CVREF pin
0 = CVREF voltage level is disconnected from CVREF pin
bit 5-4 CVRPSS<1:0>: Comparator VREF Positive Source (VPOSSRC) Selection bits
11 = Reserved, do not use. Positive source is floating
10 = VBG (Band gap)
01 = VREF+
00 = AVDD
bit 3-1 Unimplemented: Read as ‘0’
bit 0 CVRNSS: Comparator VREF Negative Source (VNEGSRC) Selection bit
01 = VREF-
00 = AVSS
32-to-1 MUX
CVR<4:0>
8R
R
CVREN
CVRSS = 0
AVDD
VREF+CVRSS = 1
R
R
R
R
R
R
32 Steps CVREF
VREF-
CVRSS = 1
CVRSS = 0
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24.2 Voltage Reference Accuracy/Error
The full range of voltage reference cannot be realized
due to the construction of the module. The transistors
on the top and bottom of the resistor ladder network
(Figure 24-1) keep CVREF from approaching the refer-
ence source rails. The voltage reference is derived
from the reference source; therefore, the CVREF output
changes with fluctuations in that source. The tested
absolute accuracy of the voltage reference can be
found in Section 31.0 “Electrical Characteristics”.
24.3 Operation During Sleep
When the device wakes up from Sleep through an
interrupt or a Watchdog Timer time-out, the contents of
the CVRCON register are not affected. To minimize
current consumption in Sleep mode, the voltage
reference should be disabled.
24.4 Effects of a Reset
A device Reset disables the voltage reference by
clearing bit, CVREN (CVRCONL<7>). This Reset also
disconnects the reference from the RF5 pin by clearing
bit, CVROE (CVRCONL<6>).
24.5 Connection Considerations
The voltage reference module operates independently
of the comparator module. The output of the reference
generator may be connected to the RA0 pin if the
CVROE bit is set. Enabling the voltage reference out-
put onto RA0, when it is configured as a digital input,
will increase current consumption. Connecting RA0 as
a digital output with CVRSS enabled will also increase
current consumption.
The RA0 pin can be used as a simple D/A output with
limited drive capability. Due to the limited current drive
capability, a buffer must be used on the voltage
reference output for external connections to VREF.
Figure 24-2 shows an example buffering technique.
FIGURE 24-2: COMPARATOR VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE
PIC18F97J94
Note 1: R is dependent upon the Comparator Voltage Reference bits, CVRCONH<4:0>, CVRCONL<5:4> and
CVRCONL<0>.
CVREF
Module R(1)
Voltage
Reference
Output
Impedance
RF5
+
–CVREF Output
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NOTES:
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25.0 HIGH/LOW-VOLTAGE DETECT
(HLVD)
The PIC18F97J94 family of devices has a High/Low-
Voltage Detect module (HLVD). This is a programmable
circuit that sets both a device voltage trip point and the
direction of change from that point. If the device experi-
ences an excursion past the trip point in that direction, an
interrupt flag is set. If the interrupt is enabled, the pro-
gram execution branches to the interrupt vector address
and the software responds to the interrupt.
The High/Low-Voltage Detect Control register
(Register 25-1) completely controls the operation of the
HLVD module. This allows the circuitry to be “turned
off” by the user under software control, which
minimizes the current consumption for the device.
The module’s block diagram is shown in Figure 25-1.
REGISTER 25-1: HLVDCON: HIGH/LOW-VOLTAGE DETECT CONTROL REGISTER
R/W-0 R-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
VDIRMAG BGVST IRVST HLVDEN HLVDL3(1)HLVDL2(1)HLVDL1(1)HLVDL0(1)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 VDIRMAG: Voltage Direction Magnitude Select bit
1 = Event occurs when voltage equals or exceeds trip point (HLVDL<3:0>)
0 = Event occurs when voltage equals or falls below trip point (HLVDL<3:0>)
bit 6 BGVST: Band Gap Reference Voltages Stable Status Flag bit
1 = Internal band gap voltage references are stable
0 = Internal band gap voltage references are not stable
bit 5 IRVST: Internal Reference Voltage Stable Flag bit
1 = Indicates that the voltage detect logic will generate the interrupt flag at the specified voltage range
0 = Indicates that the voltage detect logic will not generate the interrupt flag at the specified voltage
range and the HLVD interrupt should not be enabled
bit 4 HLVDEN: High/Low-Voltage Detect Power Enable bit
1 = HLVD is enabled
0 = HLVD is disabled
bit 3-0 HLVDL<3:0>: Voltage Detection Limit bits(1)
1111 = External analog input is used (input comes from the HLVDIN pin)
1110 = Maximum setting
.
.
.
0100 = Minimum setting
Note 1: For the electrical specifications, see Parameter D420.
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The module is enabled by setting the HLVDEN bit
(HLVDCON<4>). Each time the HLVD module is
enabled, the circuitry requires some time to stabilize.
The IRVST bit (HLVDCON<5>) is a read-only bit used
to indicate when the circuit is stable. The module can
only generate an interrupt after the circuit is stable and
IRVST is set.
The VDIRMAG bit (HLVDCON<7>) determines the
overall operation of the module. When VDIRMAG is
cleared, the module monitors for drops in VDD below a
predetermined set point. When the bit is set, the
module monitors for rises in VDD above the set point.
25.1 Operation
When the HLVD module is enabled, a comparator uses
an internally generated reference voltage as the set
point. The set point is compared with the trip point,
where each node in the resistor divider represents a
trip point voltage. The “trip point” voltage is the voltage
level at which the device detects a high or low-voltage
event, depending on the configuration of the module.
When the supply voltage is equal to the trip point, the
voltage tapped off of the resistor array is equal to the
internal reference voltage generated by the voltage
reference module. The comparator then generates an
interrupt signal by setting the HLVDIF bit.
The trip point voltage is software programmable to any of
16 values. The trip point is selected by programming the
HLVDL<3:0> bits (HLVDCON<3:0>).
The HLVD module has an additional feature that allows
the user to supply the trip voltage to the module from an
external source. This mode is enabled when bits,
HLVDL<3:0>, are set to ‘1111’. In this state, the
comparator input is multiplexed from the external input
pin, HLVDIN. This gives users the flexibility of configur-
ing the High/Low-Voltage Detect interrupt to occur at
any voltage in the valid operating range.
FIGURE 25-1: HLVD MODULE BLOCK DIAGRAM (WITH EXTERNAL INPUT)
Set
VDD
16-to-1 MUX
HLVDEN
HLVDCON
HLVDL<3:0>
Register
HLVDIN
VDD
Externally Generated
Trip Point
HLVDIF
HLVDEN
BOREN
Internal Voltage
Reference
VDIRMAG
1.2V Typical
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25.2 HLVD Setup
To set up the HLVD module:
1. Select the desired HLVD trip point by writing the
value to the HLVDL<3:0> bits.
2. Set the VDIRMAG bit to detect high voltage
(VDIRMAG = 1) or low voltage (VDIRMAG = 0).
3. Enable the HLVD module by setting the
HLVDEN bit.
4. Clear the HLVD interrupt flag (PIR2<2>), which
may have been set from a previous interrupt.
5. If interrupts are desired, enable the HLVD inter-
rupt by setting the HLVDIE and GIE bits
(PIE2<2> and INTCON<7>, respectively).
An interrupt will not be generated until the IRVST bit is
set.
25.3 Current Consumption
When the module is enabled, the HLVD comparator
and voltage divider are enabled and consume static
current.
Depending on the application, the HLVD module does
not need to operate constantly. To reduce current
requirements, the HLVD circuitry may only need to be
enabled for short periods where the voltage is checked.
After such a check, the module could be disabled.
25.4 HLVD Start-up Time
The internal reference voltage of the HLVD module,
specified in electrical specification, Parameter 37
(Section 31.0 “Electrical Characteristics”), may be
used by other internal circuitry, such as the
programmable Brown-out Reset. If the HLVD or other
circuits using the voltage reference are disabled to
lower the device’s current consumption, the reference
voltage circuit will require time to become stable before
a low or high-voltage condition can be reliably
detected. This start-up time, TIRVST, is an interval that
is independent of device clock speed. It is specified in
electrical specification, Parameter 37 (Table 31-22).
The HLVD interrupt flag is not enabled until TIRVST has
expired and a stable reference voltage is reached. For
this reason, brief excursions beyond the set point may
not be detected during this interval (see Figure 25-2 or
Figure 25-3).
Note: Before changing any module settings
(VDIRMAG, HLVDL<3:0>), first disable the
module (HLVDEN = 0), make the changes
and re-enable the module. This prevents
the generation of false HLVD events.
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FIGURE 25-2: LOW-VOLTAGE DETECT OPERATION (VDIRMAG = 0)
FIGURE 25-3: HIGH-VOLTAGE DETECT OPERATION (VDIRMAG = 1)
VHLVD
VDD
HLVDIF
VHLVD
VDD
Enable HLVD
TIRVST
HLVDIF will Not be Set
Enable HLVD
HLVDIF
HLVDIF Cleared in Software
HLVDIF Cleared in Software
HLVDIF Cleared in Software,
CASE 1:
CASE 2:
HLVDIF Remains Set Since HLVD Condition still Exists
TIRVST
Internal Reference is Stable
Internal Reference is Stable
IRVST
IRVST
VHLVD
VDD
HLVDIF
VHLVD
VDD
Enable HLVD
TIRVST
HLVDIF will not be Set
Enable HLVD
HLVDIF
HLVDIF Cleared in Software
HLVDIF Cleared in Software
HLVDIF Cleared in Software,
CASE 1:
CASE 2:
HLVDIF Remains Set since HLVD Condition still Exists
TIRVST
IRVST
Internal Reference is Stable
Internal Reference is Stable
IRVST
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25.5 Applications
In many applications, it is desirable to detect a drop
below, or rise above, a particular voltage threshold. For
example, the HLVD module could be periodically
enabled to detect Universal Serial Bus (USB) attach or
detach. This assumes the device is powered by a lower
voltage source than the USB when detached. An attach
would indicate a high-voltage detect from, for example,
3.3V to 5V (the voltage on USB) and vice versa for a
detach. This feature could save a design a few extra
components and an attach signal (input pin).
For general battery applications, Figure 25-4 shows a
possible voltage curve. Over time, the device voltage
decreases. When the device voltage reaches voltage,
VA, the HLVD logic generates an interrupt at time, TA.
The interrupt could cause the execution of an ISR, which
would allow the application to perform “housekeeping
tasks” and a controlled shutdown, before the device
voltage exits the valid operating range at TB. This would
give the application a time window, represented by the
difference between TA and TB, to safely exit.
FIGURE 25-4: TYPICAL LOW-VOLTAGE
DETECT APPLICATION
25.6 Operation During Sleep
When enabled, the HLVD circuitry continues to operate
during Sleep. If the device voltage crosses the trip
point, the HLVDIF bit will be set and the device will
wake-up from Sleep. Device execution will continue
from the interrupt vector address if interrupts have
been globally enabled.
25.7 Effects of a Reset
A device Reset forces all registers to their Reset state.
This forces the HLVD module to be turned off.
Time
Voltage
VA
VB
TATB
VA = HLVD trip point
VB = Minimum valid device
operating voltage
Legend:
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26.0 CHARGE TIME
MEASUREMENT UNIT (CTMU)
The Charge Time Measurement Unit (CTMU) is a
flexible analog module that provides accurate differen-
tial time measurement between pulse sources, as well
as asynchronous pulse generation. By working with
other on-chip analog modules, the CTMU can precisely
measure time, capacitance and relative changes in
capacitance or generate output pulses with a specific
time delay. The CTMU is ideal for interfacing with
capacitive-based sensors.
The module includes these key features:
• Up to 24 channels available for capacitive or time
measurement input
• Low-cost temperature measurement using on-chip
diode channel
• On-chip precision current source
• Sixteen-edge input trigger sources
• Polarity control for each edge source
• Provides a trigger for the A/D Converter
• Control of edge sequence
• Control of response to edges
• Time measurement resolution of 1 nanosecond
• High-precision time measurement
• Time delay of external or internal signal
asynchronous to system clock
• Accurate current source suitable for capacitive
measurement
The CTMU works in conjunction with the A/D Converter
to provide up to 24 channels for time or charge
measurement, depending on the specific device and
the number of A/D channels available. When config-
ured for time delay, the CTMU is connected to one of
the analog comparators. The level-sensitive input edge
sources can be selected from four sources: two
external inputs or the CCP1/CCP2 Special Event
Triggers.
The CTMU special event can trigger the Analog-to-Digital
Converter module.
Figure 26-1 provides a block diagram of the CTMU.
FIGURE 26-1: CTMU BLOCK DIAGRAM
CTED1
CTED2
Current Source
Edge
Control
Logic
CTMUCONH:CTMUCONL
Pulse
Generator
A/D Converter Comparator 2
Input
CCP2
CCP1
Current
Control
ITRIM<5:0>
IRNG<1:0>
CTMUCON1
CTMU
Control
Logic
EDGEN
EDGSEQEN
EDG1SEL<1:0>
EDG1POL
EDG2SEL<1:0>
EDG2POL
EDG1STAT
EDG2STAT
TGEN
IDISSEN
CTTRIG
A/D Trigger
CTPLS
Comparator 2 Output
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26.1 CTMU Registers
The control registers for the CTMU are:
• CTMUCON1
• CTMUCON2
• CTMUCON3
• CTMUCON4
The CTMUCON1 and CTMUCON3 registers
(Register 26-1 and Register 26-3) contain control bits
for configuring the CTMU module edge source selec-
tion, edge source polarity selection, edge sequencing,
A/D trigger, analog circuit capacitor discharge and
enables. The CTMUCON2 register (Register 26-2) has
bits for selecting the current source range and current
source trim.
REGISTER 26-1: CTMUCON1: CTMU CONTROL REGISTER 1
R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CTMUEN — CTMUSIDL TGEN EDGEN EDGSEQEN IDISSEN CTTRIG
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 CTMUEN: CTMU Enable bit
1 = Module is enabled
0 = Module is disabled
bit 6 Unimplemented: Read as ‘0’
bit 5 CTMUSIDL: Stop in Idle Mode bit
1 = Discontinues module operation when device enters Idle mode
0 = Continues module operation in Idle mode
bit 4 TGEN: Time Generation Enable bit
1 = Enables edge delay generation
0 = Disables edge delay generation
bit 3 EDGEN: Edge Enable bit
1 = Edges are not blocked
0 = Edges are blocked
bit 2 ESGSEQEN: Edge Sequence Enable bit
1 = Edge 1 event must occur before Edge 2 event can occur
0 = No edge sequence is needed
bit 1 IDISSEN: Analog Current Source Control bit
1 = Analog current source output is grounded
0 = Analog current source output is not grounded
bit 0 CTTRIG: CTMU Special Event Trigger bit
1 = CTMU Special Event Trigger is enabled
0 = CTMU Special Event Trigger is disabled
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REGISTER 26-2: CTMUCON2: CTMU CURRENT CONTROL REGISTER 2
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ITRIM5 ITRIM4 ITRIM3 ITRIM2 ITRIM1 ITRIM0 IRNG1 IRNG0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-2 ITRIM<5:0>: Current Source Trim bits
011111 = Maximum positive change (+62% typ.) from nominal current
011110
.
.
.
000001 = Minimum positive change (+2% typ.) from nominal current
000000 = Nominal current output specified by IRNG<1:0>
111111 = Minimum negative change (-2% typ.) from nominal current
.
.
.
100010
100001 = Maximum negative change (-62% typ.) from nominal current
bit 1-0 IRNG<1:0>: Current Source Range Select bits
11 = 100 x Base Current
10 = 10 x Base Current
01 = Base Current Level (0.55 A nominal)
00 = 1000 x Base Current
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REGISTER 26-3: CTMUCON3: CTMU CURRENT CONTROL REGISTER 3
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 U-0
EDG2EN EDG2POL EDG2SEL3 EDG2SEL2 EDG2SEL1 EDG2SEL0 — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 EDG2EN: Edge 2 Edge-Sensitive Select bit
1 = Input is edge-sensitive
0 = Input is level-sensitive
bit 6 EDG2POL: Edge 2 Polarity Select bit
1 = Edge 2 is programmed for a positive edge response
0 = Edge 2 is programmed for a negative edge response
bit 5-2 EDG2SEL<3:0>: Edge 2 Source Select bits
1111 = CMP3 selected
1110 = CMP2 selected
1101 = CMP1 selected
1100 = Reserved
1011 = CCP3 trigger selected
1010 = CCP2 trigger selected
1001 = CCP1 trigger selected
1000 = CTED13 selected
0111 = CTED12 selected
0110 = CTED11 selected
0101 = CTED10 selected
0100 = CTED9 selected
0011 = CTED1 selected
0010 = CTED2 selected
0001 = CCP1 interrupt selected
0000 = TMR1 interrupt selected
bit 1-0 Unimplemented: Read as ‘0’
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REGISTER 26-4: CTMUCON4: CTMU CURRENT CONTROL REGISTER 4
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 U-0
EDG1EN EDG1POL EDG1SEL3 EDG1SEL2 EDG1SEL1 EDG1SEL0 EDG2STAT EDG1STAT
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 EDG1EN: Edge 1 Edge-Sensitive Select bit
1 = Input is edge-sensitive
0 = Input is level-sensitive
bit 6 EDG1POL: Edge 1 Polarity Select bit
1 = Edge 1 is programmed for a positive edge response
0 = Edge 1 is programmed for a negative edge response
bit 5-2 EDG1SEL<3:0>: Edge 1 Source Select bits
1111 = CMP3 selected
1110 = CMP2 selected
1101 = CMP1 selected
1100 = CCP3 trigger selected
1011 = CCP2 trigger selected
1010 = CCP1 trigger selected
1001 = CTED8 selected
1000 = CTED7 selected
0111 = CTED6 selected
0110 = CTED5 selected
0101 = CTED4 selected
0100 = CTED3 selected
0011 = CTED1 selected
0010 = CTED2 selected
0001 = CCP1 interrupt selected
0000 = TMR1 interrupt selected
bit 1-0 EDG2STAT: Edge 2 Status bit
Indicates the status of Edge 2 and can be written to control edge source.
1 = Edge2 has occurred
0 = Edge2 has not occurred
bit 1-0 EDG1STAT: Edge 1 Status bit
1 = Edge 1 has occurred
0 = Edge 1 has not occurred
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26.2 CTMU Operation
The CTMU works by using a fixed current source to
charge a circuit. The type of circuit depends on the type
of measurement being made.
In the case of charge measurement, the current is fixed
and the amount of time the current is applied to the cir-
cuit is fixed. The amount of voltage read by the A/D
becomes a measurement of the circuit’s capacitance.
In the case of time measurement, the current, as well
as the capacitance of the circuit, is fixed. In this case,
the voltage read by the A/D is representative of the
amount of time elapsed from the time the current
source starts and stops charging the circuit.
If the CTMU is being used as a time delay, both capaci-
tance and current source are fixed, as well as the voltage
supplied to the comparator circuit. The delay of a signal
is determined by the amount of time it takes the voltage
to charge to the comparator threshold voltage.
26.2.1 THEORY OF OPERATION
The operation of the CTMU is based on the equation
for charge:
More simply, the amount of charge measured in
coulombs in a circuit is defined as current in amperes
(I), multiplied by the amount of time in seconds that the
current flows (t). Charge is also defined as the capaci-
tance in farads (C), multiplied by the voltage of the
circuit (V). It follows that:
The CTMU module provides a constant, known current
source. The A/D Converter is used to measure (V) in
the equation, leaving two unknowns: capacitance (C)
and time (t). The above equation can be used to calcu-
late capacitance or time, by either the relationship
using the known fixed capacitance of the circuit:
or by:
using a fixed time that the current source is applied to
the circuit.
26.2.2 CURRENT SOURCE
At the heart of the CTMU is a precision current source,
designed to provide a constant reference for measure-
ments. The level of current is user-selectable across
three ranges, or a total of two orders of magnitude, with
the ability to trim the output in ±2% increments
(nominal). The current range is selected by the
IRNG<1:0> bits (CTMUCON1<1:0>), with a value of
‘01’ representing the lowest range.
Current trim is provided by the ITRIM<5:0> bits
(CTMUCON1<7:2>). These six bits allow trimming of
the current source, in steps of approximately 2% per
step. Half of the range adjusts the current source posi-
tively and the other half reduces the current source. A
value of ‘000000’ is the neutral position (no change). A
value of ‘100001’ is the maximum negative adjustment
(approximately -62%) and ‘011111’ is the maximum
positive adjustment (approximately +62%).
26.2.3 EDGE SELECTION AND CONTROL
CTMU measurements are controlled by edge events
occurring on the module’s two input channels. Each chan-
nel, referred to as Edge 1 and Edge 2, can be configured
to receive input pulses from one of the edge input pins
(CTED1 and CTED2) or CCPx Special Event Triggers
(CCP1 and CCP2). The input channels are level-sensitive,
responding to the instantaneous level on the channel
rather than a transition between levels. The inputs are
selected using the EDG1SELx (CTMUCON2<5:2>) and
EDG2SELx (CTMUCON3<5:2>) bit pairs.
In addition to source, each channel can be config-
ured for event polarity using the EDGE2POL
(CTMUCON2<6>) and EDGE1POL (CTMUCON3<6>
bits. The input channels can also be filtered for an edge
event sequence (Edge 1 occurring before Edge 2) by
setting the EDGSEQEN bit (CTMUCON<2>).
26.2.4 EDGE STATUS
The CTMUCON3 register also contains two Edge
Status bits: EDG2STAT and EDG1STAT
(CTMUCON3<1:0>). Their primary function is to show
if an edge response has occurred on the corresponding
channel. The CTMU automatically sets a particular bit
when an edge response is detected on its channel. The
level-sensitive nature of the input channels also means
that the status bits become set immediately if the
channel’s configuration is changed and matches the
channel’s current state.
The module uses the Edge Status bits to control the
current source output to external analog modules (such
as the A/D Converter). Current is only supplied to exter-
nal modules when only one (not both) of the status bits
is set. Current is shut off when both bits are either set
or cleared. This allows the CTMU to measure current
only during the interval between edges. After both
status bits are set, it is necessary to clear them before
another measurement is taken. Both bits should be
cleared simultaneously, if possible, to avoid re-enabling
the CTMU current source.
In addition to being set by the CTMU hardware, the
Edge Status bits can also be set by software. This per-
mits a user application to manually enable or disable
the current source. Setting either (but not both) of the
bits enables the current source. Setting or clearing both
bits at once disables the source.
I = C • dV
dT
I • t = C • V
t = (C • V)/I
C = (I • t)/V
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26.2.5 INTERRUPTS
The CTMU sets its interrupt flag (PIR3<3>) whenever
the current source is enabled, then disabled. An inter-
rupt is generated only if the corresponding interrupt
enable bit (PIE3<3>) is also set. If edge sequencing is
not enabled (i.e., Edge 1 must occur before Edge 2), it
is necessary to monitor the Edge Status bits, and
determine which edge occurred last and caused the
interrupt.
26.3 CTMU Module Initialization
The following sequence is a general guideline used to
initialize the CTMU module:
1. Select the current source range using the
IRNGx bits (CTMUCON1<1:0>).
2. Adjust the current source trim using the ITRIMx
bits (CTMUCON1<7:2>).
3. Configure the edge input sources for Edge 1
and Edge 2 by setting the EDG1SELx and
EDG2SELx bits (CTMUCON3<5:2> and
CTMUCON2<5:2>, respectively).
4. Configure the input polarities for the edge inputs
using the EDG1POL and EDG2POL bits
(CTMUCON3<6> and CTMUCON2<6>).
The default configuration is for negative edge
polarity (high-to-low transitions).
5. Enable edge sequencing using the EDGSEQEN
bit (CTMUCON<2>).
By default, edge sequencing is disabled.
6. Select the operating mode (Measurement or
Time Delay) with the TGEN bit
(CTMUCON<4>).
The default mode is Time/Capacitance
Measurement mode.
7. Configure the module to automatically trigger
an A/D conversion when the second edge
event has occurred using the CTTRIG bit
(CTMUCON<0>).
The conversion trigger is disabled by default.
8. Discharge the connected circuit by setting the
IDISSEN bit (CTMUCON<1>).
9. After waiting a sufficient time for the circuit to
discharge, clear the IDISSEN bit.
10. Disable the module by clearing the CTMUEN bit
(CTMUCON<7>).
11. Clear the Edge Status bits, EDG2STAT and
EDG1STAT (CTMUCON3<1:0>).
Both bits should be cleared simultaneously, if
possible, to avoid re-enabling the CTMU current
source.
12. Enable both edge inputs by setting the EDGEN
bit (CTMUCON<3>).
13. Enable the module by setting the CTMUEN bit.
Depending on the type of measurement or pulse
generation being performed, one or more additional
modules may also need to be initialized and configured
with the CTMU module:
• Edge Source Generation: In addition to the
external edge input pins, CCP1/CCP2 Special
Event Triggers can be used as edge sources for
the CTMU.
• Capacitance or Time Measurement: The CTMU
module uses the A/D Converter to measure the
voltage across a capacitor that is connected to one
of the analog input channels.
• Pulse Generation: When generating system clock
independent, output pulses, the CTMU module
uses Comparator 2 and the associated
comparator voltage reference.
26.4 Calibrating the CTMU Module
The CTMU requires calibration for precise measure-
ments of capacitance and time, as well as for accurate
time delay. If the application only requires measurement
of a relative change in capacitance or time, calibration is
usually not necessary. An example of a less precise
application is a capacitive touch switch, in which the
touch circuit has a baseline capacitance and the added
capacitance of the human body changes the overall
capacitance of a circuit.
If actual capacitance or time measurement is required,
two hardware calibrations must take place:
• The current source needs calibration to set it to a
precise current.
• The circuit being measured needs calibration to
measure or nullify any capacitance other than that
to be measured.
26.4.1 CURRENT SOURCE CALIBRATION
The current source on board the CTMU module has a
range of ±62% nominal for each of three current
ranges. For precise measurements, it is possible to
measure and adjust this current source by placing a
high-precision resistor, RCAL, onto an unused analog
channel. An example circuit is shown in Figure 26-2.
To measure the current source:
1. Initialize the A/D Converter.
2. Initialize the CTMU.
3. Enable the current source by setting EDG1STAT
(CTMUCON3<0>).
4. Issue time delay for voltage across RCAL to
stabilize and the A/D Sample-and-Hold (S/H)
capacitor to charge.
5. Perform the A/D conversion.
6. Calculate the current source current using
I=V/RCAL, where RCAL is a high-precision
resistance and V is measured by performing an
A/D conversion.
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The CTMU current source may be trimmed with the
ITRIMx bits in CTMUCON1, using an iterative process
to get the exact current desired. Alternatively, the nom-
inal value without adjustment may be used. That value
may be stored by software for use in all subsequent
capacitive or time measurements.
To calculate the optimal value for RCAL, the nominal
current must be chosen.
For example, if the A/D Converter reference voltage is
3.3V, use 70% of full scale (or 2.31V) as the desired
approximate voltage to be read by the A/D Converter. If
the range of the CTMU current source is selected to be
0.55 A, the resistor value needed is calculated as
RCAL = 2.31V/0.55 A, for a value of 4.2 MΩ. Similarly,
if the current source is chosen to be 5.5 A, RCAL would
be 420,000Ω, and 42,000Ω if the current source is set
to 55 A.
FIGURE 26-2: CTMU CURRENT SOURCE
CALIBRATION CIRCUIT
A value of 70% of full-scale voltage is chosen to make
sure that the A/D Converter is in a range that is well
above the noise floor. If an exact current is chosen to
incorporate the trimming bits from CTMUCON1, the
resistor value of RCAL may need to be adjusted accord-
ingly. RCAL also may be adjusted to allow for available
resistor values. RCAL should be of the highest precision
available in light of the precision needed for the circuit
that the CTMU will be measuring. A recommended
minimum would be 0.1% tolerance.
The following examples show a typical method for
performing a CTMU current calibration.
•Example 26-1 demonstrates how to initialize the
A/D Converter and the CTMU.
This routine is typical for applications using both
modules.
•Example 26-2 demonstrates one method for the
actual calibration routine.
This method manually triggers the A/D Converter to
demonstrate the entire step-wise process. It is also
possible to automatically trigger the conversion by
setting the CTMU’s CTTRIG bit (CTMUCON<0>).
A/D Converter
CTMU
ANx
RCAL
Current Source
A/D
Trigger
MUX
A/D
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EXAMPLE 26-1: SETUP FOR CTMU CALIBRATION ROUTINES
#include "p18cxxx.h"
/**************************************************************************/
/*Setup CTMU *****************************************************************/
/**************************************************************************/
void setup(void)
{ //CTMUCON - CTMU Control register
CTMUCON = 0x00; //make sure CTMU is disabled
CTMUCON3 = 0x90;
//CTMU continues to run when emulator is stopped,CTMU continues
//to run in idle mode,Time Generation mode disabled, Edges are blocked
//No edge sequence order, Analog current source not grounded, trigger
//output disabled, Edge2 polarity = positive level, Edge2 source =
//source 0, Edge1 polarity = positive level, Edge1 source = source 0,
// Set Edge status bits to zero
//CTMUCON1 - CTMU Current Control Register
CTMUCON1 = 0x01; //0.55uA, Nominal - No Adjustment
/**************************************************************************/
//Setup AD converter;
/**************************************************************************/
TRISBbits.TRISB0=0;
TRISAbits.TRISA2=1; //set channel 2 as an input
ANCON1bits.ANSEL2=1; // Configured AN2 as an analog channel
ADCON1Hbits.FORM=0b00; // Result format 1= Right justified
ADCON1Lbits.SSRC=0b0111;
ADCON3Hbits.SAMC=0b00111; // Acquisition time 7 = 20TAD 2 = 4TAD 1=2TAD
ADCON3Lbits.ADCS=0x3F; // Clock conversion bits 6= FOSC/64 2=FOSC/32
// ADCON1
ADCON2Hbits.PVCFG=0b00; // Vref+ = AVdd
ADCON2Hbits.NVCFG0=0; // Vref- = AVss
ADCHS0Lbits.CHONA=0b000;
ADCHS0Lbits.CHOSA=0b00010; // Select ADC channel
ADCON1Hbits.ADON=1; // Turn on ADC
}
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EXAMPLE 26-2: CTMU CURRENT CALIBRATION ROUTINE
#include "p18cxxx.h"
#define COUNT 500 //@ 8MHz = 125uS.
#define DELAY for(i=0;i<COUNT;i++)
#define RCAL .027 //R value is 4200000 (4.2M)
//scaled so that result is in
//1/100th of uA
#define ADSCALE 1023 //for unsigned conversion 10 sig bits
#define ADREF 3.3 //Vdd connected to A/D Vr+
int main(void)
{
int i;
int j = 0; //index for loop
unsigned int Vread = 0;
double VTot = 0;
float Vavg=0, Vcal=0, CTMUISrc = 0; //float values stored for calcs
//assume CTMU and A/D have been setup correctly
//see Example 25-1 for CTMU & A/D setup
setup();
CTMUCONbits.CTMUEN = 1; //Enable the CTMU
for(j=0;j<10;j++)
{
CTMUCONbits.IDISSEN = 1; //drain charge on the circuit
DELAY; //wait 125us
CTMUCONbits.IDISSEN = 0; //end drain of circuit
CTMUCON3bits.EDG1STAT = 1; //Begin charging the circuit
//using CTMU current source
DELAY; //wait for 125us
CTMUCON3bits.EDG1STAT = 0; //Stop charging circuit
PIR1bits.ADIF = 0; //make sure A/D Int not set
ADCON1Lbits.SAMP=1; //and begin A/D conv.
while(!PIR1bits.ADIF); //Wait for A/D convert complete
Vread = ADRES; //Get the value from the A/D
PIR1bits.ADIF = 0; //Clear A/D Interrupt Flag
VTot += Vread; //Add the reading to the total
}
Vavg = (float)(VTot/10.000); //Average of 10 readings
Vcal = (float)(Vavg/ADSCALE*ADREF);
CTMUISrc = Vcal/RCAL; //CTMUISrc is in 1/100ths of uA
}
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26.4.2 CAPACITANCE CALIBRATION
There is a small amount of capacitance from the inter-
nal A/D Converter sample capacitor, as well as stray
capacitance from the circuit board traces and pads that
affect the precision of capacitance measurements. A
measurement of the stray capacitance can be taken by
making sure the desired capacitance to be measured
has been removed.
After removing the capacitance to be measured:
1. Initialize the A/D Converter and the CTMU.
2. Set EDG1STAT (= 1).
3. Wait for a fixed delay of time, t.
4. Clear EDG1STAT.
5. Perform an A/D conversion.
6. Calculate the stray and A/D sample capacitances:
Where:
•I is known from the current source measurement
step
•t is a fixed delay
•V is measured by performing an A/D conversion
This measured value is then stored and used for
calculations of time measurement or subtracted for
capacitance measurement. For calibration, it is
expected that the capacitance of CSTRAY +CAD is
approximately known; CAD is approximately 4 pF.
An iterative process may be required to adjust the time,
t, that the circuit is charged to obtain a reasonable volt-
age reading from the A/D Converter. The value of t may
be determined by setting COFFSET to a theoretical value
and solving for t. For example, if CSTRAY is theoretically
calculated to be 11 pF, and V is expected to be 70% of
VDD or 2.31V, t would be:
or 63 s.
See Example 26-3 for a typical routine for CTMU
capacitance calibration.
COFFSET = CSTRAY + CAD = (I • t)/V
(4 pF + 11 pF) • 2.31V/0.55 mA
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EXAMPLE 26-3: CTMU CAPACITANCE CALIBRATION ROUTINE
#include "p18cxxx.h"
#define COUNT 25 //@ 8MHz INTFRC = 62.5 us.
#define ETIME COUNT*2.5 //time in uS
#define DELAY for(i=0;i<COUNT;i++)
#define ADSCALE 1023 //for unsigned conversion 10 sig bits
#define ADREF 3.3 //Vdd connected to A/D Vr+
#define RCAL .027 //R value is 4200000 (4.2M)
//scaled so that result is in
//1/100th of uA
int main(void)
{
int i;
int j = 0; //index for loop
unsigned int Vread = 0;
float CTMUISrc, CTMUCap, Vavg, VTot, Vcal;
//assume CTMU and A/D have been setup correctly
//see Example 25-1 for CTMU & A/D setup
setup();
CTMUCONbits.CTMUEN = 1; //Enable the CTMU
for(j=0;j<10;j++)
{
CTMUCONbits.IDISSEN = 1; //drain charge on the circuit
DELAY; //wait 125us
CTMUCONbits.IDISSEN = 0; //end drain of circuit
CTMUCON3bits.EDG1STAT = 1; //Begin charging the circuit
//using CTMU current source
DELAY; //wait for 125us
CTMUCON3bits.EDG1STAT = 0; //Stop charging circuit
PIR1bits.ADIF = 0; //make sure A/D Int not set
ADCON1Lbits.SAMP=1; //and begin A/D conv.
while(!PIR1bits.ADIF); //Wait for A/D convert complete
Vread = ADRES; //Get the value from the A/D
PIR1bits.ADIF = 0; //Clear A/D Interrupt Flag
VTot += Vread; //Add the reading to the total
}
Vavg = (float)(VTot/10.000); //Average of 10 readings
Vcal = (float)(Vavg/ADSCALE*ADREF);
CTMUISrc = Vcal/RCAL; //CTMUISrc is in 1/100ths of uA
CTMUCap = (CTMUISrc*ETIME/Vcal)/100;
}
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26.5 Measuring Capacitance with the
CTMU
There are two ways to measure capacitance with the
CTMU. The absolute method measures the actual
capacitance value. The relative method only measures
for any change in the capacitance.
26.5.1 ABSOLUTE CAPACITANCE
MEASUREMENT
For absolute capacitance measurements, both the
current and capacitance calibration steps found in
Section 26.4 “Calibrating the CTMU Module” should
be followed.
To perform these measurements:
1. Initialize the A/D Converter.
2. Initialize the CTMU.
3. Set EDG1STAT.
4. Wait for a fixed delay, T.
5. Clear EDG1STAT.
6. Perform an A/D conversion.
7. Calculate the total capacitance, CTOTAL = (I * T)/V,
where:
•I is known from the current source
measurement step (Section 26.4.1 “Current
Source Calibration”)
•T is a fixed delay
•V is measured by performing an A/D conversion
8. Subtract the stray and A/D capacitance
(COFFSET from Section 26.4.2 “Capacitance
Calibration”) from CTOTAL to determine the
measured capacitance.
26.5.2 CAPACITIVE TOUCH SENSE USING
RELATIVE CHARGE
MEASUREMENT
Not all applications require precise capacitance
measurements. When detecting a valid press of a
capacitance-based switch, only a relative change of
capacitance needs to be detected.
In such an application when the switch is open (or not
touched), the total capacitance is the capacitance of the
combination of the board traces, the A/D Converter and
other elements. A larger voltage will be measured by the
A/D Converter. When the switch is closed (or touched),
the total capacitance is larger due to the addition of the
capacitance of the human body to the above listed
capacitances and a smaller voltage will be measured by
the A/D Converter.
To detect capacitance changes simply:
1. Initialize the A/D Converter and the CTMU.
2. Set EDG1STAT.
3. Wait for a fixed delay.
4. Clear EDG1STAT.
5. Perform an A/D conversion.
The voltage measured by performing the A/D conver-
sion is an indication of the relative capacitance. In this
case, no calibration of the current source or circuit
capacitance measurement is needed. (For a sample
software routine for a capacitive touch switch, see
Example 26-4.)
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EXAMPLE 26-4: CTMU ROUTINE FOR CAPACITIVE TOUCH SWITCH
#include "p18cxxx.h"
#define COUNT 500 //@ 8MHz = 125uS.
#define DELAY for(i=0;i<COUNT;i++)
#define OPENSW 1000 //Un-pressed switch value
#define TRIP 300 //Difference between pressed
//and un-pressed switch
#define HYST 65 //amount to change
//from pressed to un-pressed
#define PRESSED 1
#define UNPRESSED 0
int main(void)
{
unsigned int Vread; //storage for reading
unsigned int switchState;
int i;
//assume CTMU and A/D have been setup correctly
//see Example 25-1 for CTMU & A/D setup
setup();
CTMUCONbits.CTMUEN = 1; //Enable the CTMU
CTMUCONbits.IDISSEN = 1; //drain charge on the circuit
DELAY; //wait 125us
CTMUCONbits.IDISSEN = 0; //end drain of circuit
CTMUCON3bits.EDG1STAT = 1; //Begin charging the circuit
//using CTMU current source
DELAY; //wait for 125us
CTMUCON3bits.EDG1STAT = 0; //Stop charging circuit
PIR1bits.ADIF = 0; //make sure A/D Int not set
ADCON1Lbits.SAMP=1;; //and begin A/D conv.
while(!PIR1bits.ADIF); //Wait for A/D convert complete
Vread = ADRES; //Get the value from the A/D
if(Vread < OPENSW - TRIP)
{
switchState = PRESSED;
}
else if(Vread > OPENSW - TRIP + HYST)
{
switchState = UNPRESSED;
}
}
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26.6 Measuring Time with the CTMU
Module
Time can be precisely measured after the ratio (C/I) is
measured from the current and capacitance calibration
step. To do that:
1. Initialize the A/D Converter and the CTMU.
2. Set EDG1STAT.
3. Set EDG2STAT.
4. Perform an A/D conversion.
5. Calculate the time between edges as T = (C/I) * V,
where:
•I is calculated in the current calibration
step (Section 26.4.1 “Current Source
Calibration”)
•C is calculated in the capacitance calibra-
tion step (Section 26.4.2 “Capacitance
Calibration”)
•V is measured by performing the A/D conversion
It is assumed that the time measured is small enough
that the capacitance, CAD + CEXT, provides a valid
voltage to the A/D Converter. For the smallest time
measurement, always set the A/D Channel Select bits
via ADCON1L/H to an unused A/D channel; the corre-
sponding pin for which is not connected to any circuit
board trace. This minimizes added stray capacitance,
keeping the total circuit capacitance close to that of the
A/D Converter itself (25 pF).
To measure longer time intervals, an external capacitor
may be connected to an A/D channel and that channel
selected whenever making a time measurement.
FIGURE 26-3: CTMU TYPICAL CONNECTIONS AND INTERNAL CONFIGURATION FOR TIME
MEASUREMENT
PIC18F97J94
A/D Converter
CTMU
CTED1
CTED2
ANX
A/D Voltage
EDG1
EDG2
CAD
CEXT
Current Source
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26.7 Measuring Temperature
with the CTMU
The constant-current source provided by the CTMU
module can be used for low-cost temperature
measurement by exploiting a basic property of com-
mon and inexpensive diodes. An on-chip temperature
sense diode is provided on A/D Channel 29 to further
simplify design and cost.
26.7.1 BASIC PRINCIPAL
We can show that the forward voltage (VF) of a P-N
junction, such as a diode, is an extension of the
equation for the junction’s thermal voltage:
where k is the Boltzmann constant (1.38 x 10-23 J K-1),
T is the absolute junction temperature in kelvin, q is the
electron charge (1.6 x 10-19 C), IF is the forward current
applied to the diode and IS is the diode’s characteristic
saturation current, which varies between devices.
Since k and q are physical constants, and IS is a constant
for the device, this only leaves T and IF as independent
variables. If IF is held constant, it follows from the equa-
tion that VF will vary as a function of T. As the natural log
term of the equation will always be negative, the temper-
ature will be negatively proportional to VF. In other
words, as temperature increases, VF decreases.
By using the CTMU’s current source to provide a
constant IF, it becomes possible to calculate the
temperature by measuring the VF across the diode.
26.7.2 IMPLEMENTATION
To implement this theory, all that is needed is to
connect a regular junction diode to one of the micro-
controller’s A/D pins (Figure 26-2). The A/D channel
multiplexer is shared by the CTMU and the A/D.
To perform a measurement, the multiplexer is config-
ured to select the pin connected to the diode. The
CTMU current source is then turned on and an A/D
conversion is performed on the channel. As shown in
the equivalent circuit diagram in Figure 26-4, the diode
is driven by the CTMU at IF. The resulting VF across the
diode is measured by the A/D. A code snippet is shown
in Example 26-5.
FIGURE 26-4: CTMU TEMPERATURE
MEASUREMENT CIRCUIT
EXAMPLE 26-5: CTMU ROUTINE FOR TEMPERATURE MEASUREMENT USING INTERNAL DIODE
VF = kT
q1n 1 – IF
IS)
(
PIC® Microcontroller
A/D Converter
CTMU
Current Source
MUX
A/D
VF
VF
IF
CTMU
A/D
Equivalent Circuit
Simplified Block Diagram
// Initialize CTMU
CTMUICON = 0x03;
CTMUCONbits.CTMUEN = 1;
CTMUCON3bits.EDG1STAT = 1;
ADCON1Hbits.FORM = 0; // Right Justified
ADCON1Hbits.MODE12 = 0; // 12-Bit A/D Operation
ADCHS0Lbits.CHOSA = 0x18; // Enable ADC and connect to Internal diode
ADCON1Hbits.ADON = 1; // Enable ADC
Note: The temperature diode is not calibrated or standardized; the user must calibrate the diode to their application.
2012 Microchip Technology Inc. DS30575A-page 523
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26.8 Operation During Sleep/Idle Modes
26.8.1 SLEEP MODE
When the device enters any Sleep mode, the CTMU
module current source is always disabled. If the CTMU
is performing an operation that depends on the current
source when Sleep mode is invoked, the operation may
not terminate correctly. Capacitance and time
measurements may return erroneous values.
26.8.2 IDLE MODE
The behavior of the CTMU in Idle mode is determined
by the CTMUSIDL bit (CTMUCON<5>). If CTMUSIDL
is cleared, the module will continue to operate in Idle
mode. If CTMUSIDL is set, the module’s current source
is disabled when the device enters Idle mode. In this
case, if the module is performing an operation when
Idle mode is invoked, the results will be similar to those
with Sleep mode.
26.9 Effects of a Reset on CTMU
Upon Reset, all registers of the CTMU are cleared. This
disables the CTMU module, turns off its current source
and returns all configuration options to their default set-
tings. The module needs to be re-initialized following
any Reset.
If the CTMU is in the process of taking a measurement
at the time of Reset, the measurement will be lost. A
partial charge may exist on the circuit that was being
measured, which should be properly discharged before
the CTMU makes subsequent attempts to take a
measurement. The circuit is discharged by setting and
clearing the IDISSEN bit (CTMUCON<1>) while the A/D
Converter is connected to the appropriate channel.
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NOTES:
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27.0 UNIVERSAL SERIAL BUS
(USB)
This section describes the details of the USB peripheral.
Because of the very specific nature of the module, some
knowledge of USB is expected. Some high-level USB
information is provided in Section 27.9 “Overview of
USB” only for application design reference. Designers
are encouraged to refer to the official specification
published by the USB Implementers Forum (USB-IF) for
the latest information. USB Specification Revision 2.0 is
the most current specification at the time of publication
of this document.
27.1 Overview of the USB Peripheral
PIC18F97J94 family devices contain a full-speed and
low-speed, compatible USB Serial Interface Engine
(SIE) that allows fast communication between any USB
host and the PIC® MCU. The SIE can be interfaced
directly to the USB, utilizing the internal transceiver.
Some special hardware features have been included to
improve performance. Dual access port memory in the
device’s data memory space (USB RAM) has been
supplied to share Direct Memory Access (DMA)
between the microcontroller core and the SIE. Buffer
descriptors are also provided, allowing users to freely
program endpoint memory usage within the USB RAM
space. Figure 27-1 provides a general overview of the
USB peripheral and its features.
FIGURE 27-1: USB PERIPHERAL AND OPTIONS
3.8-Kbyte
USB RAM
USB
SIE
USB Control and
Transceiver
P
P
D+
D-
Internal Pull-ups
External 3.3V
Supply
FSEN
UPUEN
UTRDIS
USB Clock from the
Oscillator Module
Optional
External
Pull-ups(1)
(Low(Full
USB Bus
FS
Speed) Speed)
Note 1: The internal pull-up resistors should be disabled (UPUEN = 0) if external pull-up resistors are used.
Configuration
VUSB3V3
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27.2 USB Status and Control
The operation of the USB module is configured and
managed through three control registers. In addition, a
total of 22 registers are used to manage the actual USB
transactions. The registers are:
• USB Control Register (UCON)
• USB Configuration Register (UCFG)
• USB Transfer Status Register (USTAT)
• USB Device Address Register (UADDR)
• Frame Number Registers (UFRMH:UFRML)
• Endpoint Enable Registers 0 through 15 (UEPn)
27.2.1 USB CONTROL REGISTER (UCON)
The USB Control register (Register 27-1) contains bits
needed to control the module behavior during transfers.
The register contains bits that control the following:
• Main USB Peripheral Enable
• Ping-Pong Buffer Pointer Reset
• Control of the Suspend mode
• Packet Transfer Disable
In addition, the USB Control register contains a status
bit, SE0 (UCON<5>), which is used to indicate the
occurrence of a single-ended zero on the bus. When
the USB module is enabled, this bit should be
monitored to determine whether the differential data
lines have come out of a single-ended zero condition.
This helps to differentiate the initial power-up state from
the USB Reset signal.
The overall operation of the USB module is controlled
by the USBEN bit (UCON<3>). Setting this bit activates
the module and resets all of the PPBI bits in the Buffer
Descriptor Table (BDT) to ‘0’. This bit also activates the
internal pull-up resistors if they are enabled. Thus, this
bit can be used as a soft attach/detach to the USB.
Although all status and control bits are ignored when
this bit is clear, the module needs to be fully preconfig-
ured prior to setting this bit. The USB clock source
should have been already configured for the correct
frequency and running. If the PLL is being used, it
should be enabled for at least 2 ms (enough time for
the PLL to lock) before attempting to set the USBEN
bit.
Note: When disabling the USB module, make
sure the SUSPND bit (UCON<1>) is clear
prior to clearing the USBEN bit. Clearing
the USBEN bit when the module is in the
suspended state may prevent the module
from fully powering down
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REGISTER 27-1: UCON: USB CONTROL REGISTER
U-0 R/W-0 R-x R/C-0 R/W-0 R/W-0 R/W-0 U-0
— PPBRST(2)SE0 PKTDIS USBEN(1)RESUME SUSPND —
bit 7 bit 0
Legend: C = Clearable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6 PPBRST: Ping-Pong Buffers Reset bit(2)
1 = Reset all Ping-Pong Buffer Pointers to the Even Buffer Descriptor (BD) banks
0 = Ping-Pong Buffer Pointers are not being reset
bit 5 SE0: Live Single-Ended Zero Flag bit
1 = Single-ended zero is active on the USB bus
0 = No single-ended zero is detected
bit 4 PKTDIS: Packet Transfer Disable bit
1 = SIE token and packet processing are disabled, automatically set when a SETUP token is received
0 = SIE token and packet processing are enabled
bit 3 USBEN: USB Module Enable bit(1)
1 = USB module and supporting circuitry are enabled (device attached)
0 = USB module and supporting circuitry are disabled (device detached)
bit 2 RESUME: Resume Signaling Enable bit
1 = Resume signaling is activated
0 = Resume signaling is disabled
bit 1 SUSPND: Suspend USB bit
1 = USB module and supporting circuitry are in Power Conserve mode, SIE clock is inactive
0 = USB module and supporting circuitry are in normal operation, SIE is clocked at the configured rate
bit 0 Unimplemented: Read as ‘0’
Note 1: Make sure the USB clock source is correctly configured before setting this bit.
2: There should be at least four cycles of delay between the setting and PPBRST.
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The PPBRST bit (UCON<6>) controls the Reset status
when Double-Buffering mode (ping-pong buffering) is
used. When the PPBRST bit is set, all Ping-Pong
Buffer Pointers are set to the Even buffers. PPBRST
has to be cleared by firmware. This bit is ignored in
buffering modes not using ping-pong buffering.
The PKTDIS bit (UCON<4>) is a flag indicating that the
SIE has disabled packet transmission and reception.
This bit is set by the SIE when a SETUP token is
received to allow setup processing. This bit cannot be
set by the microcontroller, only cleared; clearing it
allows the SIE to continue transmission and/or
reception. Any pending events within the Buffer
Descriptor Table (BDT) will still be available, indicated
within the USTAT register’s FIFO buffer.
The RESUME bit (UCON<2>) allows the peripheral to
perform a remote wake-up by executing resume
signaling. To generate a valid remote wake-up,
firmware must set RESUME for 10 ms and then clear
the bit. For more information on resume signaling, see
Sections 7.1.7.5, 11.4.4 and 11.9 in the “USB 2.0
Specification”.
The SUSPND bit (UCON<1>) places the module and
supporting circuitry in a Low-Power mode. The input
clock to the SIE is also disabled. This bit should be set
by the software in response to an IDLEIF interrupt. It
should be reset by the microcontroller firmware after an
ACTVIF interrupt is observed. When this bit is active,
the device remains attached to the bus but the
transceiver outputs remain Idle. The voltage on the
VUSB3V3 pin may vary depending on the value of this
bit. Setting this bit before a IDLEIF request will result in
unpredictable bus behavior.
27.2.2 USB CONFIGURATION REGISTER
(UCFG)
Prior to communicating over USB, the module’s
associated internal and/or external hardware must be
configured. Most of the configuration is performed with
the UCFG register (Register 27-2).The UFCG register
contains most of the bits that control the system-level
behavior of the USB module. These include:
• Bus Speed (full speed versus low speed)
• On-Chip Pull-up Resistor Enable
• On-Chip Transceiver Enable
• Ping-Pong Buffer Usage
The UCFG register also contains two bits, which aid in
module testing, debugging and USB certifications.
These bits control output enable state monitoring and
eye pattern generation.
27.2.2.1 Internal Transceiver
The USB peripheral has a built-in, “USB 2.0 Specifica-
tion”, full-speed and low-speed capable transceiver,
internally connected to the SIE. This feature is useful
for low-cost, single chip applications. The UTRDIS bit
(UCFG<3>) controls the transceiver; it is enabled by
default (UTRDIS = 0). The FSEN bit (UCFG<2>)
controls the transceiver speed; setting this bit enables
full-speed operation.
The on-chip USB pull-up resistors are controlled by the
UPUEN bit (UCFG<4>). They can only be selected
when the on-chip transceiver is enabled.
The internal USB transceiver obtains power from the
VUSB3V3 pin. In order to meet USB signalling level
specifications, VUSB3V3 must be supplied with a voltage
source between 3.0V and 3.6V. The best electrical sig-
nal quality is obtained when a 3.3V supply is used and
locally bypassed with a high quality ceramic capacitor
(ex: 0.1 F). The capacitor should be placed as close
as possible to the VUSB3V3 and VSS pins.
VUSB3V3 should always be maintained VDD. If the
USB module is not used, but RC4 or RC5 are used as
general purpose inputs, VUSB3V3 should still be con-
nected to a power source (such as VDD). The input
thresholds for the RC4 and RC5 pins are dependent
upon the VUSB3V3 supply level.
The D+ and D- signal lines can be routed directly to
their respective pins on the USB connector or cable (for
hard-wired applications). No additional resistors,
capacitors or magnetic components are required, as
the D+ and D- drivers have controlled slew rate and
output impedance, intended to match with the
characteristic impedance of the USB cable.
In order to achieve optimum USB signal quality, the D+
and D- traces between the microcontroller and USB
connector (or cable) should be less than 19 cm long.
Both traces should be equal in length and they should
be routed parallel to each other. Ideally, these traces
should be designed to have a characteristic impedance
matching that of the USB cable.
Note: While in Suspend mode, a typical bus-
powered USB device is limited to 2.5 mA
of current. This is the complete current
which may be drawn by the PIC MCU
device and its supporting circuitry. Care
should be taken to assure minimum
current draw when the device enters
Suspend mode.
Note: The USB speed, transceiver and pull-up
should only be configured during the
module setup phase. It is not recom-
mended to switch these settings while the
module is enabled.
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REGISTER 27-2: UCFG: USB CONFIGURATION REGISTER
R/W-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
UTEYE UOEMON — UPUEN(1,2)UTRDIS(1,3)FSEN(1)PPB1 PPB0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 UTEYE: USB Eye Pattern Test Enable bit
1 = Eye pattern test is enabled
0 = Eye pattern test is disabled
bit 6 UOEMON: USB OE Monitor Enable bit
1 =UOE
signal is active, indicating intervals during which the D+/D- lines are driving
0 =UOE
signal is inactive
bit 5 Unimplemented: Read as ‘0’
bit 4 UPUEN: USB On-Chip Pull-up Enable bit(1,2)
1 = On-chip pull-up is enabled (pull-up on D+ with FSEN = 1 or D- with FSEN = 0)
0 = On-chip pull-up is disabled
bit 3 UTRDIS: On-Chip Transceiver Disable bit(1,3)
1 = On-chip transceiver is disabled
0 = On-chip transceiver is active
bit 2 FSEN: Full-Speed Enable bit(1)
1 = Full-speed device: Controls transceiver edge rates; requires input clock at 48 MHz
0 = Low-speed device: Controls transceiver edge rates; requires input clock at 6 MHz
bit 1-0 PPB<1:0>: Ping-Pong Buffers Configuration bits
11 = Even/Odd ping-pong buffers are enabled for Endpoints 1 to 15
10 = Even/Odd ping-pong buffers are enabled for all endpoints
01 = Even/Odd ping-pong buffer are enabled for OUT Endpoint 0
00 = Even/Odd ping-pong buffers are disabled
Note 1: The UPUEN, UTRDIS and FSEN bits should never be changed while the USB module is enabled. These
values must be preconfigured prior to enabling the module.
2: This bit is only valid when the on-chip transceiver is active (UTRDIS = 0); otherwise, it is ignored.
3: If UTRDIS is set, the UOE signal will be active, independent of the UOEMON bit setting.
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27.2.2.2 Internal Pull-up Resistors
The PIC18F97J94 family devices have built-in pull-up
resistors, designed to meet the requirements for low-
speed and full-speed USB. The UPUEN bit (UCFG<4>)
enables the internal pull-ups. Figure 27-1 shows the
pull-ups and their control.
27.2.2.3 External Pull-up Resistors
External pull-ups may also be used. The VUSB3V3 pin
may be used to pull up D+ or D-. The pull-up resistor
must be 1.5 k (±5%) as required by the USB
specifications.
Figure 27-2 provides an example of external circuitry.
FIGURE 27-2: EXTERNAL CIRCUITRY
27.2.2.4 Ping-Pong Buffer Configuration
The usage of ping-pong buffers is configured using the
PPB<1:0> bits. Refer to Section 27.4.4 “Ping-Pong
Buffering” for a complete explanation of the ping-pong
buffers.
27.2.2.5 Eye Pattern Test Enable
An automatic eye pattern test can be generated by the
module when the UCFG<7> bit is set. The eye pattern
output will be observable based on module settings,
meaning that the user is first responsible for configuring
the SIE clock settings, pull-up resistor and Transceiver
mode. In addition, the module has to be enabled.
Once UTEYE is set, the module emulates a switch from
a receive to transmit state and will start transmitting a
J-K-J-K bit sequence (K-J-K-J for full speed). The
sequence will be repeated indefinitely while the Eye
Pattern Test mode is enabled.
Note that this bit should never be set while the module
is connected to an actual USB system. This Test mode
is intended for board verification to aid with USB certi-
fication tests. It is intended to show a system developer
the noise integrity of the USB signals which can be
affected by board traces, impedance mismatches and
proximity to other system components. It does not
properly test the transition from a receive to a transmit
state. Although the eye pattern is not meant to replace
the more complex USB certification test, it should aid
during first order system debugging.
Note: A compliant USB device should never
source any current onto the +5V VBUS line
of the USB cable. Additionally, USB
devices should not source any current on
the D+ and D- data lines whenever the
+5V VBUS line is less than 1.17V. In order
to be USB compliant, applications which
are not purely bus-powered should moni-
tor the VBUS line, and avoid turning on the
USB module and the D+ or D- pull-up
resistor until VBUS is greater than 1.17V.
VBUS can be connected to and monitored
by a 5V tolerant I/O pin, or if a resistive
divider is used, by an analog capable pin.
PIC®MCU Host
Controller/HUB
VUSB3V3
D+
D-
Note: The above setting shows a typical connection
for a full-speed configuration using an on-chip
regulator and an external pull-up resistor.
1.5 k
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27.2.3 USB STATUS REGISTER (USTAT)
The USB Status register reports the transaction status
within the SIE. When the SIE issues a USB transfer
complete interrupt, USTAT should be read to determine
the status of the transfer. USTAT contains the transfer
endpoint number, direction and Ping-Pong Buffer
Pointer value (if used).
The USTAT register is actually a read window into a
4-byte status FIFO, maintained by the SIE. It allows the
microcontroller to process one transfer while the SIE
processes additional endpoints (Figure 27-3). When
the SIE completes using a buffer for reading or writing
data, it updates the USTAT register. If another USB
transfer is performed before a transaction complete
interrupt is serviced, the SIE will store the status of the
next transfer into the status FIFO.
Clearing the Transfer Complete Flag bit, TRNIF,
causes the SIE to advance the FIFO. If the next data in
the FIFO holding register is valid, the SIE will reassert
the interrupt within 5 TCY of clearing TRNIF. If no addi-
tional data is present, TRNIF will remain clear; USTAT
data will no longer be reliable.
FIGURE 27-3: USTAT FIFO
Note: The data in the USB Status register is
valid only when the TRNIF interrupt flag is
asserted.
Note: If an endpoint request is received while
the USTAT FIFO is full, the SIE will
automatically issue a NAK back to the host.
Data Bus
USTAT from SIE
4-Byte FIFO
for USTAT
Clearing TRNIF
Advances FIFO
REGISTER 27-3: USTAT: USB STATUS REGISTER (ACCESS F64H)
U-0 R-x R-x R-x R-x R-x R-x U-0
— ENDP3 ENDP2 ENDP1 ENDP0 DIR PPBI(1)—
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-3 ENDP<3:0>: Encoded Number of Last Endpoint Activity bits
(represents the number of the BDT updated by the last USB transfer)
1111 = Endpoint 15
1110 = Endpoint 14
.
.
.
0001 = Endpoint 1
0000 = Endpoint 0
bit 2 DIR: Last BD Direction Indicator bit
1 = The last transaction was an IN token
0 = The last transaction was an OUT or SETUP token
bit 1 PPBI: Ping-Pong BD Pointer Indicator bit(1)
1 = The last transaction was to the Odd BD bank
0 = The last transaction was to the Even BD bank
bit 0 Unimplemented: Read as ‘0’
Note 1: This bit is only valid for endpoints with available Even and Odd BD registers.
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27.2.4 USB ENDPOINT CONTROL
Each of the 16 possible bidirectional endpoints has its
own independent control register, UEPn (where ‘n’
represents the endpoint number). Each register has an
identical complement of control bits.
Register 27-4 provides the prototype.
The EPHSHK bit (UEPn<4>) controls handshaking for
the endpoint; setting this bit enables USB handshaking.
Typically, this bit is always set except when using
isochronous endpoints.
The EPCONDIS bit (UEPn<3>) is used to enable or
disable USB control operations (SETUP) through the
endpoint. Clearing this bit enables SETUP transac-
tions. Note that the corresponding EPINEN and
EPOUTEN bits must be set to enable IN and OUT
transactions. For Endpoint 0, this bit should always be
cleared since the USB specifications identify
Endpoint 0 as the default control endpoint.
The EPOUTEN bit (UEPn<2>) is used to enable or
disable USB OUT transactions from the host. Setting
this bit enables OUT transactions. Similarly, the
EPINEN bit (UEPn<1>) enables or disables USB IN
transactions from the host.
The EPSTALL bit (UEPn<0>) is used to indicate a
STALL condition for the endpoint. If a STALL is issued
on a particular endpoint, the EPSTALL bit for that end-
point pair will be set by the SIE. This bit remains set
until it is cleared through firmware or until the SIE is
reset.
REGISTER 27-4: UEPn: USB ENDPOINT n CONTROL REGISTER (UEP0 THROUGH UEP15)
U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— — — EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘0’
bit 4 EPHSHK: Endpoint Handshake Enable bit
1 = Endpoint handshake is enabled
0 = Endpoint handshake is disabled (typically used for isochronous endpoints)
bit 3 EPCONDIS: Bidirectional Endpoint Control bit
If EPOUTEN = 1 and EPINEN = 1:
1 = Disables Endpoint n from control transfers; only IN and OUT transfers are allowed
0 = Enables Endpoint n for control (SETUP) transfers; IN and OUT transfers are also allowed
bit 2 EPOUTEN: Endpoint Output Enable bit
1 = Endpoint n output is enabled
0 = Endpoint n output is disabled
bit 1 EPINEN: Endpoint Input Enable bit
1 = Endpoint n input is enabled
0 = Endpoint n input is disabled
bit 0 EPSTALL: Endpoint Stall Indicator bit
1 = Endpoint n has issued one or more STALL packets
0 = Endpoint n has not issued any STALL packets
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27.2.5 USB ADDRESS REGISTER
(UADDR)
The USB Address register contains the unique USB
address that the peripheral will decode when active.
UADDR is reset to 00h when a USB Reset is received,
indicated by URSTIF, or when a Reset is received from
the microcontroller. The USB address must be written
by the microcontroller during the USB setup phase
(enumeration) as part of the Microchip USB firmware
support.
27.2.6 USB FRAME NUMBER REGISTERS
(UFRMH:UFRML)
The Frame Number registers contain the 11-bit frame
number. The low-order byte is contained in UFRML,
while the three high-order bits are contained in
UFRMH. The register pair is updated with the current
frame number whenever a SOF token is received. For
the microcontroller, these registers are read-only. The
Frame Number registers are primarily used for
isochronous transfers. The contents of the UFRMH and
UFRML registers are only valid when the 48 MHz SIE
clock is active (i.e., contents are inaccurate when
SUSPND (UCON<1>) bit = 1).
27.3 USB RAM
USB data moves between the microcontroller core and
the SIE through a memory space, known as the USB
RAM. This is a special dual access memory that is
mapped into the normal data memory space in Banks 0
through 14 (00h to EBFh), for a total of 3.8 Kbytes
(Figure 27-4).
Bank 13 (D00h through DFFh) is used specifically for
endpoint buffer control, while Banks 0 through 12 and
Bank 14 are available for USB data. Depending on the
type of buffering being used, all but 8 bytes of Bank 13
may also be available for use as USB buffer space.
Although USB RAM is available to the microcontroller
as data memory, the sections that are being accessed
by the SIE should not be accessed by the micro-
controller. A semaphore mechanism is used to
determine the access to a particular buffer at any given
time. This is discussed in Section 27.4.1.1 “Buffer
Ownership”.
FIGURE 27-4: IMPLEMENTATION OF
USB RAM IN DATA
MEMORY SPACE
D00h
DFFh
E00h
USB Data or
Buffer Descriptors,
USB Data or User Data
User Data
CFFh
000h
FFFh
Banks 0
(USB RAM)
to 14
Access Ram
060h
05Fh
EC0h
EBFh
SFRs
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27.4 Buffer Descriptors and the Buffer
Descriptor Table
The registers in Bank 13 are used specifically for end-
point buffer control in a structure known as the Buffer
Descriptor Table (BDT). This provides a flexible method
for users to construct and control endpoint buffers of
various lengths and configuration.
The BDT is composed of Buffer Descriptors (BD) which
are used to define and control the actual buffers in the
USB RAM space. Each BD, in turn, consists of four
registers, where n represents one of the 64 possible
BDs (range of 0 to 63):
• BDnSTAT: BD Status Register
• BDnCNT: BD Byte Count Register
• BDnADRL: BD Address Low Register
• BDnADRH: BD Address High Register
BDs always occur as a four-byte block in
the sequence,
BDnSTAT:BDnCNT:BDnADRL:BDnADRH.
The address
of BDnSTAT is always an offset of (4n – 1, in hexa-
decimal) from D00h, with n being the buffer descriptor
number.
Depending on the buffering configuration used
(Section 27.4.4 “Ping-Pong Buffering”), there are up
to 32, 33 or 64 sets of buffer descriptors. At a minimum,
the BDT must be at least 8 bytes long. This is because
the USB Specification mandates that every device
must have Endpoint 0 with both input and output for ini-
tial setup. Depending on the endpoint and buffering
configuration, the BDT can be as long as 256 bytes.
Although they can be thought of as Special Function
Registers, the Buffer Descriptor Status and Address
registers are not hardware mapped, as conventional
microcontroller SFRs in Bank 15 are. If the endpoint cor-
responding to a particular BD is not enabled, its registers
are not used. Instead of appearing as unimplemented
addresses, however, they appear as available RAM.
Only when an endpoint is enabled by setting the
UEPn<1> bit does the memory at those addresses
become functional as BD registers. As with any address
in the data memory space, the BD registers have an
indeterminate value on any device Reset.
Figure 27-5 provides an example of a BD for a 64-byte
buffer, starting at 500h. A particular set of BD registers
is only valid if the corresponding endpoint has been
enabled using the UEPn register. All BD registers are
available in USB RAM. The BD for each endpoint
should be set up prior to enabling the endpoint.
27.4.1 BD STATUS AND CONFIGURATION
Buffer descriptors not only define the size of an end-
point buffer, but also determine its configuration and
control. Most of the configuration is done with the BD
Status register, BDnSTAT. Each BD has its own unique
and correspondingly numbered BDnSTAT register.
FIGURE 27-5: EXAMPLE OF A BUFFER
DESCRIPTOR
Unlike other control registers, the bit configuration for
the BDnSTAT register is context-sensitive. There are
two distinct configurations, depending on whether the
microcontroller or the USB module is modifying the BD
and buffer at a particular time. Only three bit definitions
are shared between the two.
27.4.1.1 Buffer Ownership
Because the buffers and their BDs are shared between
the CPU and the USB module, a simple semaphore
mechanism is used to distinguish which is allowed to
update the BD and associated buffers in memory.
This is done by using the UOWN bit (BDnSTAT<7>) as
a semaphore to distinguish which is allowed to update
the BD and associated buffers in memory. UOWN is the
only bit that is shared between the two configurations
of BDnSTAT.
When UOWN is clear, the BD entry is “owned” by the
microcontroller core. When the UOWN bit is set, the BD
entry and the buffer memory are “owned” by the USB
peripheral. The core should not modify the BD or its
corresponding data buffer during this time. Note that
the microcontroller core can still read BDnSTAT while
the SIE owns the buffer and vice versa.
The buffer descriptors have a different meaning based
on the source of the register update. Prior to placing
ownership with the USB peripheral, the user can
configure the basic operation of the peripheral through
the BDnSTAT bits. During this time, the byte count and
buffer location registers can also be set.
When UOWN is set, the user can no longer depend on
the values that were written to the BDs. From this point,
the SIE updates the BDs as necessary, overwriting the
original BD values. The BDnSTAT register is updated
by the SIE with the token PID and the transfer count,
BDnCNT, is updated.
D00h
USB Data
Buffer
Buffer
BD0STAT
BD0CNT
BD0ADRL
BD0ADRH
D01h
D02h
D03h
500h
53Fh
Descriptor
Note: Memory regions are not to scale.
40h
00h
05h
Starting
Size of Block
(xxh)
RegistersAddress Contents
Address
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The BDnSTAT byte of the BDT should always be the
last byte updated when preparing to arm an endpoint.
The SIE will clear the UOWN bit when a transaction
has completed.
No hardware mechanism exists to block access when
the UOWN bit is set. Thus, unexpected behavior can
occur if the microcontroller attempts to modify memory
when the SIE owns it. Similarly, reading such memory
may produce inaccurate data until the USB peripheral
returns ownership to the microcontroller.
27.4.1.2 BDnSTAT Register (CPU Mode)
When UOWN = 0, the microcontroller core owns the
BD. At this point, the other seven bits of the register
take on control functions.
The Data Toggle Sync Enable bit, DTSEN
(BDnSTAT<3>), controls data toggle parity checking.
Setting DTSEN enables data toggle synchronization by
the SIE. When enabled, it checks the data packet’s par-
ity against the value of DTS (BDnSTAT<6>). If a packet
arrives with an incorrect synchronization, the data will
essentially be ignored. It will not be written to the USB
RAM and the USB transfer complete interrupt flag will
not be set. The SIE will send an ACK token back to the
host to Acknowledge receipt, however. The effects of the
DTSEN bit on the SIE are summarized in Table 27-1.
The Buffer Stall bit, BSTALL (BDnSTAT<2>), provides
support for control transfers, usually one-time stalls on
Endpoint 0. It also provides support for the
SET_FEATURE/CLEAR_FEATURE commands speci-
fied in Chapter 9 of the USB Specification; typically,
continuous STALLs to any endpoint other than the
default control endpoint.
The BSTALL bit enables buffer stalls. Setting BSTALL
causes the SIE to return a STALL token to the host if a
received token would use the BD in that location. The
EPSTALL bit in the corresponding UEPn Control
register is set and a STALL interrupt is generated when
a STALL is issued to the host. The UOWN bit remains
set and the BDs are not changed unless a SETUP
token is received. In this case, the STALL condition is
cleared and the ownership of the BD is returned to the
microcontroller core.
The BC<9:8> bits (BDnSTAT<1:0>) store the two most
significant digits of the SIE byte count. The lower 8 digits
are stored in the corresponding BDnCNT register. See
Section 27.4.2 “BD Byte Count” for more information.
TABLE 27-1: EFFECT OF DTSEN BIT ON ODD/EVEN (DATA0/DATA1) PACKET RECEPTION
OUT Packet
from Host
BDnSTAT Settings Device Response after Receiving Packet
DTSEN DTS Handshake UOWN TRNIF BDnSTAT and USTAT Status
DATA0 10ACK 01 Updated
DATA1 10ACK 10 Not Updated
DATA0 11ACK 10 Not Updated
DATA1 11ACK 01 Updated
Either 0xACK 01 Updated
Either, with error xxNAK 10 Not Updated
Legend: x = don’t care
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REGISTER 27-5: BDnSTAT: BUFFER DESCRIPTOR n STATUS REGISTER (BD0STAT THROUGH
BD63STAT), CPU MODE
R/W-x R/W-x U-0 U-0 R/W-x R/W-x R/W-x R/W-x
UOWN(1)DTS(2)—(3)—(3)DTSEN BSTALL BC9 BC8
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 UOWN: USB Own bit(1)
0 = The microcontroller core owns the BD and its corresponding buffer
bit 6 DTS: Data Toggle Synchronization bit(2)
1 = Data 1 packet
0 = Data 0 packet
bit 5-4 Unimplemented: These bits should always be programmed to ‘0’(3)
bit 3 DTSEN: Data Toggle Synchronization Enable bit
1 = Data toggle synchronization is enabled; data packets with incorrect Sync value will be ignored,
except for a SETUP transaction, which is accepted even if the data toggle bits do not match
0 = No data toggle synchronization is performed
bit 2 BSTALL: Buffer Stall Enable bit
1 = Buffer stall is enabled; STALL handshake issued if a token is received that would use the BD in
the given location (UOWN bit remains set, BD value is unchanged)
0 = Buffer stall is disabled
bit 1-0 BC<9:8>: Byte Count 9 and 8 bits
The byte count bits represent the number of bytes that will be transmitted for an IN token or received
during an OUT token. Together with BC<7:0>, the valid byte counts are 0-1023.
Note 1: This bit must be initialized by the user to the desired value prior to enabling the USB module.
2: This bit is ignored unless DTSEN = 1.
3: If these bits are set, USB communication may not work. Hence, these bits should always be maintained as
‘0’.
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27.4.1.3 BDnSTAT Register (SIE Mode)
When the BD and its buffer are owned by the SIE, most
of the bits in BDnSTAT take on a different meaning. The
configuration is shown in Register 27-6. Once UOWN
is set, any data or control settings previously written
there by the user will be overwritten with data from the
SIE.
The BDnSTAT register is updated by the SIE with the
token Packet Identifier (PID) which is stored in
BDnSTAT<5:2>. The transfer count in the correspond-
ing BDnCNT register is updated. Values that overflow
the 8-bit register carry over to the two most significant
digits of the count, stored in BDnSTAT<1:0>.
27.4.2 BD BYTE COUNT
The byte count represents the total number of bytes
that will be transmitted during an IN transfer. After an IN
transfer, the SIE will return the number of bytes sent to
the host.
For an OUT transfer, the byte count represents the
maximum number of bytes that can be received and
stored in USB RAM. After an OUT transfer, the SIE will
return the actual number of bytes received. If the
number of bytes received exceeds the corresponding
byte count, the data packet will be rejected and a NAK
handshake will be generated. When this happens, the
byte count will not be updated.
The 10-bit byte count is distributed over two registers.
The lower 8 bits of the count reside in the BDnCNT
register; the upper two bits reside in BDnSTAT<1:0>.
This represents a valid byte range of 0 to 1023.
27.4.3 BD ADDRESS VALIDATION
The BD Address register pair contains the starting RAM
address location for the corresponding endpoint buffer.
No mechanism is available in hardware to validate the
BD address.
If the value of the BD address does not point to an
address in the USB RAM, or if it points to an address
within another endpoint’s buffer, data is likely to be lost
or overwritten. Similarly, overlapping a receive buffer
(OUT endpoint) with a BD location in use can yield
unexpected results. When developing USB
applications, the user may want to consider the
inclusion of software-based address validation in their
code.
REGISTER 27-6: BDnSTAT: BUFFER DESCRIPTOR n STATUS REGISTER (BD0STAT THROUGH
BD63STAT), SIE MODE (DATA RETURNED BY THE SIE TO THE MCU)
R/W-x r-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
UOWN r PID3 PID2 PID1 PID0 BC9 BC8
bit 7 bit 0
Legend: r = Reserved bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 UOWN: USB Own bit
1 = The SIE owns the BD and its corresponding buffer
bit 6 Reserved: Not written by the SIE
bit 5-2 PID<3:0>: Packet Identifier bits
The received token PID value of the last transfer (IN, OUT or SETUP transactions only).
bit 1-0 BC<9:8>: Byte Count 9 and 8 bits
These bits are updated by the SIE to reflect the actual number of bytes received on an OUT transfer
and the actual number of bytes transmitted on an IN transfer.
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27.4.4 PING-PONG BUFFERING
An endpoint is defined to have a ping-pong buffer when
it has two sets of BD entries: one set for an Even
transfer and one set for an Odd transfer. This allows the
CPU to process one BD while the SIE is processing the
other BD. Double-buffering BDs in this way allows for
maximum throughput to/from the USB.
The USB module supports four modes of operation:
• No ping-pong support
• Ping-pong buffer support for OUT Endpoint 0 only
• Ping-pong buffer support for all endpoints
• Ping-pong buffer support for all other endpoints
except Endpoint 0
The ping-pong buffer settings are configured using the
PPB<1:0> bits in the UCFG register.
The USB module keeps track of the Ping-Pong Pointer
individually for each endpoint. All pointers are initially
reset to the Even BD when the module is enabled. After
the completion of a transaction (UOWN cleared by the
SIE), the pointer is toggled to the Odd BD. After the
completion of the next transaction, the pointer is
toggled back to the Even BD and so on.
The Even/Odd status of the last transaction is stored in
the PPBI bit of the USTAT register. The user can reset
all Ping-Pong Pointers to Even using the PPBRST bit.
Figure 27-6 shows the four different modes of
operation and how USB RAM is filled with the BDs.
BDs have a fixed relationship to a particular endpoint,
depending on the buffering configuration. Tab le 27- 2
provides the mapping of BDs to endpoints. This
relationship also means that gaps may occur in the
BDT if endpoints are not enabled contiguously. This,
theoretically, means that the BDs for disabled
endpoints could be used as buffer space. In practice,
users should avoid using such spaces in the BDT
unless a method of validating BD addresses is
implemented.
FIGURE 27-6: BUFFER DESCRIPTOR TABLE MAPPING FOR BUFFERING MODES
EP1 IN Even
EP1 OUT Even
EP1 OUT Odd
EP1 IN Odd
Descriptor
Descriptor
Descriptor
Descriptor
EP1 IN
EP15 IN
EP1 OUT
EP0 OUT
PPB<1:0> = 00
EP0 IN
EP1 IN
No Ping-Pong
EP15 IN
EP0 IN
EP0 OUT Even
PPB<1:0> = 01
EP0 OUT Odd
EP1 OUT
Ping-Pong Buffer
EP15 IN Odd
EP0 IN Even
EP0 OUT Even
PPB<1:0> = 10
EP0 OUT Odd
EP0 IN Odd
Ping-Pong Buffers
Descriptor
Descriptor
Descriptor
Descriptor
Descriptor
Descriptor
Descriptor
Descriptor
Descriptor
Descriptor
Descriptor
Descriptor
D00h
DFFh DFFh DFFh
D00h D00h
D7Fh
D83h
Available
as
Data RAM Available
as
Data RAM
Maximum Memory
Used: 128 bytes
Maximum BDs: 32
(BD0 to BD31)
Maximum Memory
Used: 132 bytes
Maximum BDs: 33
(BD0 to BD32)
Maximum Memory
Used: 256 bytes
Maximum BDs: 64
(BD0 to BD63)
Note: Memory area is not shown to scale.
Descriptor
Descriptor
Descriptor
Descriptor
Buffers on EP0 OUT on All EPs
EP1 IN Even
EP1 OUT Even
EP1 OUT Odd
EP1 IN Odd
Descriptor
Descriptor
Descriptor
Descriptor
EP15 IN Odd
EP0 OUT
PPB<1:0> = 11
EP0 IN
Ping-Pong Buffers
Descriptor
Descriptor
Descriptor
DFFh
D00h
Maximum Memory
Used: 248 bytes
Maximum BDs: 62
(BD0 to BD61)
on All Other EPs
Except EP0
Available
as
Data RAM
DF7h
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TABLE 27-2: ASSIGNMENT OF BUFFER DESCRIPTORS FOR THE DIFFERENT
BUFFERING MODES
TABLE 27-3: SUMMARY OF USB BUFFER DESCRIPTOR TABLE REGISTERS
Endpoint
BDs Assigned to Endpoint
Mode 0
(No Ping-Pong)
Mode 1
(Ping-Pong on EP0 OUT)
Mode 2
(Ping-Pong on All EPs)
Mode 3
(Ping-Pong on All Other
EPs, except EP0)
Out In Out In Out In Out In
0 0 1 0 (E), 1 (O) 2 0 (E), 1 (O) 2 (E), 3 (O) 0 1
1 2 3 3 4 4 (E), 5 (O) 6 (E), 7 (O) 2 (E), 3 (O) 4 (E), 5 (O)
2 4 5 5 6 8 (E), 9 (O) 10 (E), 11 (O) 6 (E), 7 (O) 8 (E), 9 (O)
3 6 7 7 8 12 (E), 13 (O) 14 (E), 15 (O) 10 (E), 11 (O) 12 (E), 13 (O)
4 8 9 9 10 16 (E), 17 (O) 18 (E), 19 (O) 14 (E), 15 (O) 16 (E), 17 (O)
5 10 11 11 12 20 (E), 21 (O) 22 (E), 23 (O) 18 (E), 19 (O) 20 (E), 21 (O)
6 12 13 13 14 24 (E), 25 (O) 26 (E), 27 (O) 22 (E), 23 (O) 24 (E), 25 (O)
7 14 15 15 16 28 (E), 29 (O) 30 (E), 31 (O) 26 (E), 27 (O) 28 (E), 29 (O)
8 16 17 17 18 32 (E), 33 (O) 34 (E), 35 (O) 30 (E), 31 (O) 32 (E), 33 (O)
9 18 19 19 20 36 (E), 37 (O) 38 (E), 39 (O) 34 (E), 35 (O) 36 (E), 37 (O)
10 20 21 21 22 40 (E), 41 (O) 42 (E), 43 (O) 38 (E), 39 (O) 40 (E), 41 (O)
11 22 23 23 24 44 (E), 45 (O) 46 (E), 47 (O) 42 (E), 43 (O) 44 (E), 45 (O)
12 24 25 25 26 48 (E), 49 (O) 50 (E), 51 (O) 46 (E), 47 (O) 48 (E), 49 (O)
13 26 27 27 28 52 (E), 53 (O) 54 (E), 55 (O) 50 (E), 51 (O) 52 (E), 53 (O)
14 28 29 29 30 56 (E), 57 (O) 58 (E), 59 (O) 54 (E), 55 (O) 56 (E), 57 (O)
15 30 31 31 32 60 (E), 61 (O) 62 (E), 63 (O) 58 (E), 59 (O) 60 (E), 61 (O)
Legend: (E) = Even transaction buffer, (O) = Odd transaction buffer
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
BDnSTAT(1)UOWN DTS(4)PID3(2)PID2(2)PID1(2)
DTSEN(3)
PID0(2)
BSTALL(3)
BC9 BC8
BDnCNT(1)Byte Count
BDnADRL(1)Buffer Address Low
BDnADRH(1)Buffer Address High
Note 1: For buffer descriptor registers, n may have a value of 0 to 63. For the sake of brevity, all 64 registers are
shown as one generic prototype. All registers have indeterminate Reset values (xxxx xxxx).
2: Bits 5 through 2 of the BDnSTAT register are used by the SIE to return PID<3:0> values once the register
is turned over to the SIE (UOWN bit is set). Once the registers have been under SIE control, the values
written for DTSEN and BSTALL are no longer valid.
3: Prior to turning the buffer descriptor over to the SIE (UOWN bit is cleared), bits 5 through 2 of the
BDnSTAT register are used to configure the DTSEN and BSTALL settings.
4: This bit is ignored unless DTSEN = 1.
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27.5 USB Interrupts
The USB module can generate multiple interrupt condi-
tions. To accommodate all of these interrupt sources,
the module is provided with its own interrupt logic struc-
ture, similar to that of the microcontroller. USB interrupts
are enabled with one set of control registers and
trapped with a separate set of flag registers. All sources
are funneled into a single USB Oscillator Fail Interrupt
Flag bit, USBIF (PIR2<4>), in the microcontroller’s
interrupt logic.
Figure 27-7 provides the interrupt logic for the USB
module. There are two layers of interrupt registers in
the USB module. The top level consists of overall USB
status interrupts; these are enabled and flagged in the
UIE and UIR registers, respectively. The second level
consists of USB error conditions, which are enabled
and flagged in the UEIR and UEIE registers. An
interrupt condition in any of these triggers a USB Error
Interrupt Flag (UERRIF) in the top level.
Interrupts may be used to trap routine events in a USB
transaction. Figure 27-8 provides some common
events within a USB frame and its corresponding
interrupts.
FIGURE 27-7: USB INTERRUPT LOGIC FUNNEL
FIGURE 27-8: EXAMPLE OF A USB TRANSACTION AND INTERRUPT EVENTS
BTSEF
BTSEE
BTOEF
BTOEE
DFN8EF
DFN8EE
CRC16EF
CRC16EE
CRC5EF
CRC5EE
PIDEF
PIDEE
SOFIF
SOFIE
TRNIF
TRNIE
IDLEIF
IDLEIE
STALLIF
STALLIE
ACTVIF
ACTVIE
URSTIF
URSTIE
UERRIF
UERRIE
USBIF
Second Level USB Interrupts
(USB Error Conditions
UEIR (Flag) and UEIE (Enable) Registers
Top Level USB Interrupts
(USB Status Interrupts
UIR (Flag) and UIE (Enable) Registers
USB Reset
SOFRESET SETUP DATA STATUS SOF
SETUP Token Data ACK
OUT Token Empty Data ACKStart-of-Frame (SOF)
IN Token Data ACK
SOFIF
URSTIF
1 ms Frame
Differential Data
From Host From Host To Host
From Host To Host From Host
From Host From Host To Host
Transaction
Control Transfer(1)
Transaction
Complete
Note 1: The control transfer shown here is only an example showing events that can occur for every transaction. Typical
control transfers will spread across multiple frames.
Set TRNIF
Set TRNIF
Set TRNIF
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27.5.1 USB INTERRUPT STATUS
REGISTER (UIR)
The USB Interrupt Status register (Register 27-7) con-
tains the flag bits for each of the USB status interrupt
sources. Each of these sources has a corresponding
interrupt enable bit in the UIE register. All of the USB
status flags are ORed together to generate the USBIF
interrupt flag for the microcontroller’s interrupt funnel.
Once an interrupt bit has been set by the SIE, it must
be cleared in software by writing a ‘0’. The flag bits can
also be set in software, which can aid in firmware
debugging.
When the USB module is in the Low-Power Suspend
mode (UCON<1> = 1), the SIE does not get clocked.
When in this state, the SIE cannot process packets,
and therefore, cannot detect new interrupt conditions
other than the Activity Detect Interrupt, ACTVIF. The
ACTVIF bit is typically used by USB firmware to detect
when the microcontroller should bring the USB module
out of the Low-Power Suspend mode (UCON<1> = 0).
Register 27-7: UIR: USB INTERRUPT STATUS REGISTER (ACCESS F62h)
U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R-0 R/W-0
— SOFIF STALLIF IDLEIF(1)TRNIF(2)ACTVIF(3)UERRIF(4)URSTIF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6 SOFIF: Start-of-Frame Token Interrupt bit
1 = A Start-of-Frame token is received by the SIE
0 = No Start-of-Frame token is received by the SIE
bit 5 STALLIF: A STALL Handshake Interrupt bit
1 = A STALL handshake was sent by the SIE
0 = A STALL handshake has not been sent
bit 4 IDLEIF: Idle Detect Interrupt bit(1)
1 = Idle condition is detected (constant Idle state of 3 ms or more)
0 = No Idle condition is detected
bit 3 TRNIF: Transaction Complete Interrupt bit(2)
1 = Processing of pending transaction is complete; read the USTAT register for endpoint information
0 = Processing of pending transaction is not complete or no transaction is pending
bit 2 ACTVIF: Bus Activity Detect Interrupt bit(3)
1 = Activity on the D+/D- lines was detected
0 = No activity detected on the D+/D- lines
bit 1 UERRIF: USB Error Condition Interrupt bit(4)
1 = An unmasked error condition has occurred
0 = No unmasked error condition has occurred.
bit 0 URSTIF: USB Reset Interrupt bit
1 = Valid USB Reset occurred; 00h is loaded into the UADDR register
0 = No USB Reset has occurred
Note 1: Once an Idle state is detected, the user may want to place the USB module in Suspend mode.
2: Clearing this bit will cause the USTAT FIFO to advance (valid only for IN, OUT and SETUP tokens).
3: This bit is typically unmasked only following the detection of a UIDLE interrupt event.
4: Only error conditions enabled through the UEIE register will set this bit. This bit is a status bit only and
cannot be set or cleared by the user.
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DS30575A-page 542 2012 Microchip Technology Inc.
27.5.1.1 Bus Activity Detect Interrupt Bit
(ACTVIF)
The ACTVIF bit cannot be cleared immediately after
the USB module wakes up from Suspend mode or
while the USB module is suspended. A few clock
cycles are required to synchronize the internal hard-
ware state machine before the ACTVIF bit can be
cleared by firmware. Clearing the ACTVIF bit before
the internal hardware is synchronized may not have an
effect on the value of ACTVIF. Additionally, if the USB
module uses the clock from the 96 MHz PLL source,
then after clearing the SUSPND bit, the USB module
may not be immediately operational while waiting for
the 96 MHz PLL to lock. The application code should
clear the ACTVIF flag as provided in Example 27-1.
EXAMPLE 27-1: CLEARING ACTVIF BIT (UIR<2>)
Note: Only one ACTVIF interrupt is generated
when resuming from the USB bus Idle con-
dition. If user firmware clears the ACTVIF
bit, the bit will not immediately become set
again, even when there is continuous bus
traffic. Bus traffic must cease long enough
to generate another IDLEIF condition
before another ACTVIF interrupt can be
generated.
Assembly:
BCF UCON, SUSPND
LOOP:
BTFSS UIR, ACTVIF
BRA DONE
BCF UIR, ACTVIF
BRA LOOP
DONE:
C:
UCONbits.SUSPND = 0;
while (UIRbits.ACTVIF) { UIRbits.ACTVIF = 0; }
2012 Microchip Technology Inc. DS30575A-page 543
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27.5.2 USB INTERRUPT ENABLE
REGISTER (UIE)
The USB Interrupt Enable (UIE) register (Register 27-8)
contains the enable bits for the USB status interrupt
sources. Setting any of these bits will enable the
respective interrupt source in the UIR register.
The values in this register only affect the propagation
of an interrupt condition to the microcontroller’s inter-
rupt logic. The flag bits are still set by their interrupt
conditions, allowing them to be polled and serviced
without actually generating an interrupt.
Register 27-8: UIE: USB INTERRUPT ENABLE REGISTER
U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— SOFIE STALLIE IDLEIE TRNIE ACTVIE UERRIE URSTIE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6 SOFIE: Start-of-Frame Token Interrupt Enable bit
1 = Start-of-Frame token interrupt is enabled
0 = Start-of-Frame token interrupt is disabled
bit 5 STALLIE: STALL Handshake Interrupt Enable bit
1 = STALL interrupt is enabled
0 = STALL interrupt is disabled
bit 4 IDLEIE: Idle Detect Interrupt Enable bit
1 = Idle detect interrupt is enabled
0 = Idle detect interrupt is disabled
bit 3 TRNIE: Transaction Complete Interrupt Enable bit
1 = Transaction interrupt is enabled
0 = Transaction interrupt is disabled
bit 2 ACTVIE: Bus Activity Detect Interrupt Enable bit
1 = Bus activity detect interrupt is enabled
0 = Bus activity detect interrupt is disabled
bit 1 UERRIE: USB Error Interrupt Enable bit
1 = USB error interrupt is enabled
0 = USB error interrupt is disabled
bit 0 URSTIE: USB Reset Interrupt Enable bit
1 = USB Reset interrupt is enabled
0 = USB Reset interrupt is disabled
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DS30575A-page 544 2012 Microchip Technology Inc.
27.5.3 USB ERROR INTERRUPT STATUS
REGISTER (UEIR)
The USB Error Interrupt Status register (Register 27-9)
contains the flag bits for each of the error sources
within the USB peripheral. Each of these sources is
controlled by a corresponding interrupt enable bit in
the UEIE register. All of the USB error flags are ORed
together to generate the USB Error Interrupt Flag
(UERRIF) at the top level of the interrupt logic.
Each error bit is set as soon as the error condition is
detected. Thus, the interrupt will typically not
correspond with the end of a token being processed.
Once an interrupt bit has been set by the SIE, it must
be cleared in software by writing a ‘0’.
Register 27-9: UEIR: USB ERROR INTERRUPT STATUS REGISTER (ACCESS F63h)
R/C-0 U-0 U-0 R/C-0 R/C-0 R/C-0 R/C-0 R/C-0
BTSEF —— BTOEF DFN8EF CRC16EF CRC5EF PIDEF
bit 7 bit 0
Legend: C = Clearable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 BTSEF: Bit Stuff Error Flag bit
1 = A bit stuff error has been detected
0 = No bit stuff error has been detected
bit 6-5 Unimplemented: Read as ‘0’
bit 4 BTOEF: Bus Turnaround Time-out Error Flag bit
1 = Bus turnaround time-out has occurred (more than 16 bit times of Idle from previous EOP elapsed)
0 = No bus turnaround time-out has occurred
bit 3 DFN8EF: Data Field Size Error Flag bit
1 = The data field was not an integral number of bytes
0 = The data field was an integral number of bytes
bit 2 CRC16EF: CRC16 Failure Flag bit
1 = The CRC16 failed
0 = The CRC16 passed
bit 1 CRC5EF: CRC5 Host Error Flag bit
1 = The token packet was rejected due to a CRC5 error
0 = The token packet was accepted
bit 0 PIDEF: PID Check Failure Flag bit
1 = PID check failed
0 = PID check passed
2012 Microchip Technology Inc. DS30575A-page 545
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27.5.4 USB ERROR INTERRUPT ENABLE
REGISTER (UEIE)
The USB Error Interrupt Enable register
(Register 27-10) contains the enable bits for each of
the USB error interrupt sources. Setting any of these
bits will enable the respective error interrupt source in
the UEIR register to propagate into the UERR bit at
the top level of the interrupt logic.
As with the UIE register, the enable bits only affect the
propagation of an interrupt condition to the micro-
controller’s interrupt logic. The flag bits are still set by
their interrupt conditions, allowing them to be polled
and serviced without actually generating an interrupt.
Register 27-10: UEIE: USB ERROR INTERRUPT ENABLE REGISTER (BANKED F37h)
R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
BTSEE —— BTOEE DFN8EE CRC16EE CRC5EE PIDEE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 BTSEE: Bit Stuff Error Interrupt Enable bit
1 = Bit stuff error interrupt is enabled
0 = Bit stuff error interrupt is disabled
bit 6-5 Unimplemented: Read as ‘0’
bit 4 BTOEE: Bus Turnaround Time-out Error Interrupt Enable bit
1 = Bus turnaround time-out error interrupt is enabled
0 = Bus turnaround time-out error interrupt is disabled
bit 3 DFN8EE: Data Field Size Error Interrupt Enable bit
1 = Data field size error interrupt is enabled
0 = Data field size error interrupt is disabled
bit 2 CRC16EE: CRC16 Failure Interrupt Enable bit
1 = CRC16 failure interrupt is enabled
0 = CRC16 failure interrupt is disabled
bit 1 CRC5EE: CRC5 Host Error Interrupt Enable bit
1 = CRC5 host error interrupt is enabled
0 = CRC5 host error interrupt is disabled
bit 0 PIDEE: PID Check Failure Interrupt Enable bit
1 = PID check failure interrupt is enabled
0 = PID check failure interrupt is disabled
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DS30575A-page 546 2012 Microchip Technology Inc.
27.6 USB Power Modes
Many USB applications will likely have several different
sets of power requirements and configuration. The
most common power modes encountered are Bus
Power Only, Self-Power Only and Dual Power with
Self-Power Dominance. The most common cases are
presented here. Also provided is a means of estimating
the current consumption of the USB transceiver.
27.6.1 BUS POWER ONLY
In Bus Power Only mode, all power for the application
is drawn from the USB (Figure 27-9). This is effectively
the simplest power method for the device.
In order to meet the inrush current requirements of the
“USB 2.0 Specification”, the total effective capacitance
appearing across VBUS and ground must be no more
than 10 µF. If not, some kind of inrush timing is
required. For more details, see Section 7.2.4 of the
“USB 2.0 Specification”.
According to the “USB 2.0 Specification”, all USB
devices must also support a Low-Power Suspend
mode. In the USB Suspend mode, devices must
consume no more than 2.5 mA from the 5V VBUS line
of the USB cable.
The host signals the USB device to enter the Suspend
mode by stopping all USB traffic to that device for more
than 3 ms. This condition will cause the IDLEIF bit in
the UIR register to become set.
During the USB Suspend mode, the D+ or D- pull-up
resistor must remain active, which will consume some
of the allowed suspend current: 2.5 mA budget.
FIGURE 27-9: BUS POWER ONLY
27.6.2 SELF-POWER ONLY
In Self-Power Only mode, the USB application provides
its own power, with very little power being pulled from
the USB. See Figure 27-10 for an example.
Note that an attach indication is added to indicate when
the USB has been connected and the host is actively
powering VBUS.
In order to meet compliance specifications, the USB
module (and the D+ or D- pull-up resistor) should not be
enabled until the host actively drives VBUS high. One of
the 5.5V tolerant I/O pins may be used for this purpose.
The application should never source any current onto
the 5V VBUS pin of the USB cable.
FIGURE 27-10: SELF-POWER ONLY
27.6.3 DUAL POWER WITH SELF-POWER
DOMINANCE
Some applications may require a dual power option.
This allows the application to use internal power
primarily, but switch to power from the USB when no
internal power is available. See Figure 27-11 for a
simple Dual Power with Self-Power Dominance mode
example, which automatically switches between Self-
Power Only and USB Bus Power Only modes.
Dual power devices must also meet all of the special
requirements for inrush current and Suspend mode
current, and must not enable the USB module until
VBUS is driven high. See Section 27.6.1 “Bus Power
Only” and Section 27.6.2 “Self-Power Only” for
descriptions of those requirements. Additionally, dual
power devices must never source current onto the 5V
VBUS pin of the USB cable.
FIGURE 27-11: DUAL POWER WITH
SELF-POWER
DOMINANCE
VDD
VUSB3V3
VSS
VBUS
~5V
3.3V
Low IQ Regulator
Note: Users should keep in mind the limits for
devices drawing power from the USB.
According to USB Specification 2.0, this
cannot exceed 100 mA per low-power
device or 500 mA per high-power device.
VDD
VUSB3V3
VSS
VSELF
~3.3V
Attach Sense
100 k
100 k
VBUS
~5V
5.5V Tolerant
I/O Pin
VDD
VUSB3V3
I/O Pin
VSS
Attach Sense
VBUS
VSELF
100 k
~3.3V
~5V
100 k
3.3V
Low IQ
Regulator
2012 Microchip Technology Inc. DS30575A-page 547
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27.6.4 USB TRANSCEIVER CURRENT
CONSUMPTION
The USB transceiver consumes a variable amount of
current depending on the characteristic impedance of
the USB cable, the length of the cable, the VUSB3V3
supply voltage and the actual data patterns moving
across the USB cable. Longer cables have larger
capacitances and consume more total energy when
switching output states.
Data patterns that consist of “IN” traffic consume far
more current than “OUT” traffic. IN traffic requires the
PIC® MCU to drive the USB cable, whereas OUT traffic
requires that the host drive the USB cable.
The data that is sent across the USB cable is NRZI
encoded. In the NRZI encoding scheme, ‘0’ bits cause
a toggling of the output state of the transceiver (either
from a “J” state to a “K” state or vise versa). With the
exception of the effects of bit stuffing, NRZI encoded ‘1’
bits do not cause the output state of the transceiver to
change. Therefore, IN traffic consisting of data bits of
value, ‘0’, cause the most current consumption, as the
transceiver must charge/discharge the USB cable in
order to change states.
More details about NRZI encoding and bit stuffing can
be found in the “USB 2.0 Specification”, Section 7.1,
although knowledge of such details is not required to
make USB applications using the PIC18F97J94 family
of microcontrollers. Among other things, the SIE handles
bit stuffing/unstuffing, NRZI encoding/decoding and
CRC generation/checking in hardware.
The total transceiver current consumption will be
application-specific. However, to help estimate how
much current actually may be required in full-speed
applications, Equation 27-1 can be used.
See Equation 27-2 to know how this equation can be
used for a theoretical application.
EQUATION 27-1: ESTIMATING USB TRANSCEIVER CURRENT CONSUMPTION
I
XCVR
=
+ I
PULLUP
(4
0 mA • V
USB
3
V
3
• P
ZERO
• P
IN
• L
CABLE
)
(3.3V • 5
m)
Legend: VUSB3V3 – Voltage applied to the VUSB3V3 pin in volts (should be 3.0V to 3.6V).
PZERO – Percentage (in decimal) of the IN traffic bits sent by the PIC® MCU that are a value of ‘0’.
PIN – Percentage (in decimal) of total bus bandwidth that is used for IN traffic.
LCABLE – Length (in meters) of the USB cable. The “USB 2.0 Specification” requires that full-speed
applications use cables no longer than 5m.
IPULLUP – Current which the nominal, 1.5 k pull-up resistor (when enabled) must supply to the USB
cable. On the host or hub end of the USB cable, 15 k nominal resistors (14.25 k to 24.8 k) are
present which pull both the D+ and D- lines to ground. During bus Idle conditions (such as between
packets or during USB Suspend mode), this results in up to 218 A of quiescent current drawn at 3.3V.
IPULLUP is also dependant on bus traffic conditions and can be as high as 2.2 mA when the USB bandwidth
is fully utilized (either IN or OUT traffic) for data that drives the lines to the “K” state most of the time.
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DS30575A-page 548 2012 Microchip Technology Inc.
EQUATION 27-2: CALCULATING USB TRANSCEIVER CURRENT†
For this example, the following assumptions are made about the application:
• 3.3V will be applied to VUSB3V3 and VDD, with the core voltage regulator enabled.
• This is a full-speed application that uses one interrupt IN endpoint that can send one packet of 64 bytes every
1 ms, with no restrictions on the values of the bytes being sent. The application may or may not have additional
traffic on OUT endpoints.
• A regular USB “B” or “mini-B” connector will be used on the application circuit board.
In this case, PZERO = 100% = 1, because there should be no restriction on the value of the data moving through the
IN endpoint. All 64 kbps of data could potentially be bytes of value, 00h. Since ‘0’ bits cause toggling of the output state
of the transceiver, they cause the USB transceiver to consume extra current charging/discharging the cable. In this
case, 100% of the data bits sent can be of value ‘0’. This should be considered the “max” value, as normal data will
consist of a fair mix of ones and zeros.
This application uses 64 kbps for IN traffic out of the total bus bandwidth of 1.5 Mbps (12 Mbps), therefore:
Since a regular “B” or “mini-B” connector is used in this application, the end user may plug in any type of cable up to
the maximum allowed 5m length. Therefore, we use the worst-case length:
LCABLE = 5 meters
Assume IPULLUP = 2.2 mA. The actual value of IPULLUP will likely be closer to 218 A, but allowance for the worst-case.
USB bandwidth is shared between all the devices which are plugged into the root port (via hubs). If the application is
plugged into a USB 1.1 hub that has other devices plugged into it, your device may see host to device traffic on the
bus, even if it is not addressed to your device. Since any traffic, regardless of source, can increase the IPULLUP current
above the base 218 A, it is safest to allow for the worst-case of 2.2 mA.
Therefore:
† The calculated value should be considered an approximation and additional guardband or application-
specific product testing is recommended. The transceiver current is “in addition to” the
rest of the current consumed by the PIC18F97J94 family device that is needed to run the core,
drive the other I/O lines, power the various modules, etc.
Pin = 64 kbps
1.5 Mbps = 4.3% = 0.043
IXCVR = + 2.2 mA = 3.9 mA
(40 mA • 3.3V • 1 • 0.043 • 5m)
(3.3V • 5m)
2012 Microchip Technology Inc. DS30575A-page 549
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27.7 Oscillator
The USB module has specific clock requirements. For
full-speed operation, the clock source must be 48 MHz.
Even so, the microcontroller core and other peripherals
are not required to run at that clock speed.
27.8 USB Firmware and Drivers
Microchip provides a number of application-specific
resources, such as USB firmware and driver support.
Refer to www.microchip.com for the latest firmware and
driver support.
TABLE 27-4: REGISTERS ASSOCIATED WITH USB MODULE OPERATION(1)
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE IOCIE TMR0IF INT0IF IOCIF
IPR2 OSCFIP SSP2IP BCL2IP USBIP BCL1IP HLVDIP TMR3IP TMR3GIP
PIR2 OSCFIF SSP2IF BCL2IF USBIF BCL1IF HLVDIF TMR3IF TMR3GIF
PIE2 OSCFIE SSP2IE BCL2IE USBIE BCL1IE HLVDIE TMR3IE TMR3GIE
UCON — PPBRST SE0 PKTDIS USBEN RESUME SUSPND —
UCFG UTEYE UOEMON — UPUEN UTRDIS FSEN PPB1 PPB0
USTAT — ENDP3 ENDP2 ENDP1 ENDP0 DIR PPBI —
UADDR — ADDR6 ADDR5 ADDR4 ADDR3 ADDR2 ADDR1 ADDR0
UFRML FRM7 FRM6 FRM5 FRM4 FRM3 FRM2 FRM1 FRM0
UFRMH — — — — —FRM10FRM9FRM8
UIR — SOFIF STALLIF IDLEIF TRNIF ACTVIF UERRIF URSTIF
UIE — SOFIE STALLIE IDLEIE TRNIE ACTVIE UERRIE URSTIE
UEIR BTSEF —— BTOEF DFN8EF CRC16EF CRC5EF PIDEF
UEIE BTSEE —— BTOEE DFN8EE CRC16EE CRC5EE PIDEE
UEP0 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP1 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP2 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP3 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP4 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP5 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP6 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP7 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP8 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP9 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP10 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP11 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP12 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP13 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP14 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
UEP15 ——— EPHSHK EPCONDIS EPOUTEN EPINEN EPSTALL
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the USB module.
Note 1: This table includes only those hardware mapped SFRs located in Bank 15 of the data memory space. The Buffer
Descriptor registers, which are mapped into Bank 4 and are not true SFRs, are listed separately in Table 27-3.
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DS30575A-page 550 2012 Microchip Technology Inc.
27.9 Overview of USB
This section presents some of the basic USB concepts
and useful information necessary to design a USB
device. Although much information is provided in this
section, there is a plethora of information provided
within the USB specifications and class specifications.
Thus, the reader is encouraged to refer to the USB
specifications for more information (www.usb.org). If
you are very familiar with the details of USB, then this
section serves as a basic, high-level refresher of USB.
27.9.1 LAYERED FRAMEWORK
USB device functionality is structured into a layered
framework, graphically illustrated in Figure 27-12.
Each level is associated with a functional level within
the device. The highest layer, other than the device, is
the configuration. A device may have multiple configu-
rations. For example, a particular device may have
multiple power requirements based on Self-Power Only
or Bus Power Only modes.
For each configuration, there may be multiple
interfaces. Each interface could support a particular
mode of that configuration.
Below the interface is the endpoint(s). Data is directly
moved at this level. There can be as many as
16 bidirectional endpoints. Endpoint 0 is always a
control endpoint, and by default, when the device is on
the bus, Endpoint 0 must be available to configure the
device.
27.9.2 FRAMES
Information communicated on the bus is grouped into
1 ms time slots, referred to as frames. Each frame can
contain many transactions to various devices and
endpoints. See Figure 27-8 for an example of a
transaction within a frame.
27.9.3 TRANSFERS
There are four transfer types defined in the USB
specification.
•Isochronous: This type provides a transfer
method for large amounts of data (up to
1023 bytes) with timely delivery ensured;
however, the data integrity is not ensured. This is
good for streaming applications where small data
loss is not critical, such as audio.
•Bulk: This type of transfer method allows for large
amounts of data to be transferred with ensured
data integrity; however, the delivery timeliness is
not ensured.
•Interrupt: This type of transfer provides for
ensured timely delivery for small blocks of data,
plus data integrity is ensured.
•Control: This type provides for device setup control.
While full-speed devices support all transfer types, low-
speed devices are limited to interrupt and control
transfers only.
27.9.4 POWER
Power is available from the USB. The USB specifica-
tion defines the bus power requirements. Devices may
either be self-powered or bus-powered. Self-powered
devices draw power from an external source, while
bus-powered devices use power supplied from the bus.
FIGURE 27-12: USB LAYERS
Device
Endpoint Endpoint Endpoint Endpoint Endpoint
To Other Configurations (if any)
To Other Interfaces (if any)
Configuration
Interface
Interface
2012 Microchip Technology Inc. DS30575A-page 551
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The USB Specification limits the power taken from the
bus. Each device is ensured 100 mA at approximately
5V (one unit load). Additional power may be requested,
up to a maximum of 500 mA.
Note that power above one unit load is a request and
the host or hub is not obligated to provide the extra cur-
rent. Thus, a device capable of consuming more than
one unit load must be able to maintain a low-power
configuration of a one unit load or less, if necessary.
The USB Specification also defines a Suspend mode.
In this situation, current must be limited to 500 A,
averaged over one second. A device must enter a
suspend state after 3 ms of inactivity (i.e., no SOF
tokens for 3 ms). A device entering Suspend mode
must drop current consumption within 10 ms after
suspend. Likewise, when signaling a wake-up, the
device must signal a wake-up within 10 ms of drawing
current above the suspend limit.
27.9.5 ENUMERATION
When the device is initially attached to the bus, the host
enters an enumeration process in an attempt to identify
the device. Essentially, the host interrogates the device,
gathering information, such as power consumption, data
rates and sizes, protocol and other descriptive
information; descriptors contain this information. A
typical enumeration process would be as follows:
1. USB Reset – Reset the device. Thus, the device
is not configured and does not have an address
(Address 0).
2. Get Device Descriptor – The host requests a
small portion of the device descriptor.
3. USB Reset – Reset the device again.
4. Set Address – The host assigns an address to
the device.
5. Get Device Descriptor – The host retrieves the
device descriptor, gathering info, such as
manufacturer, type of device, maximum control
packet size.
6. Get configuration descriptors.
7. Get any other descriptors.
8. Set a configuration.
The exact enumeration process depends on the host.
27.9.6 DESCRIPTORS
There are eight different standard descriptor types, of
which, five are most important for this device.
27.9.6.1 Device Descriptor
The device descriptor provides general information,
such as manufacturer, product number, serial number,
the class of the device and the number of configurations.
There is only one device descriptor.
27.9.6.2 Configuration Descriptor
The configuration descriptor provides information on
the power requirements of the device and how many
different interfaces are supported when in this configu-
ration. There may be more than one configuration for a
device (i.e., low-power and high-power configurations).
27.9.6.3 Interface Descriptor
The interface descriptor details the number of end-
points used in this interface, as well as the class of the
interface. There may be more than one interface for a
configuration.
27.9.6.4 Endpoint Descriptor
The endpoint descriptor identifies the transfer type
(Section 27.9.3 “Transfers”) and direction, and some
other specifics for the endpoint. There may be many
endpoints in a device and endpoints may be shared in
different configurations.
27.9.6.5 String Descriptor
Many of the previous descriptors reference one or
more string descriptors. String descriptors provide
human readable information about the layer
(Section 27.9.1 “Layered Framework”) they
describe. Often these strings show up in the host to
help the user identify the device. String descriptors are
generally optional to save memory and are encoded in
a unicode format.
27.9.7 BUS SPEED
Each USB device must indicate its bus presence and
speed to the host. This is accomplished through a
1.5 k resistor, which is connected to the bus at the
time of the attachment event.
Depending on the speed of the device, the resistor
either pulls up the D+ or D- line to 3.3V. For a low-
speed device, the pull-up resistor is connected to the
D- line. For a full-speed device, the pull-up resistor is
connected to the D+ line.
27.9.8 CLASS SPECIFICATIONS AND
DRIVERS
USB specifications include class specifications, which
operating system vendors optionally support.
Examples of classes include: Audio, Mass Storage,
Communications and Human Interface (HID). In most
cases, a driver is required at the host side to ‘talk’ to the
USB device. In custom applications, a driver may need
to be developed. Fortunately, drivers are available for
most common host systems for the most common
classes of devices. Thus, these drivers can be reused.
PIC18F97J94 FAMILY
DS30575A-page 552 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 553
PIC18F97J94 FAMILY
28.0 SPECIAL FEATURES OF THE
CPU
The PIC18F97J94 family of devices includes several
features intended to maximize reliability and minimize
cost through elimination of external components.
These include:
• Oscillator Selection
• Resets:
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
• Watchdog Timer (WDT) and On-chip Regulator
• Fail-Safe Clock Monitor
• Two-Speed Start-up
• Code Protection
• ID Locations
• In-Circuit Serial Programming™
The oscillator can be configured for the application
depending on frequency, power, accuracy and cost. All
of the options are discussed in detail in Section 3.0
“Oscillator Configurations”.
A complete discussion of device Resets and interrupts
is available in previous sections of this data sheet.
In addition to their Power-up and Oscillator Start-up
Timers provided for Resets, the PIC18F97J94 family of
devices has a Watchdog Timer, which is either perma-
nently enabled via the Configuration bits or software
controlled (if configured as disabled).
The inclusion of an internal RC Oscillator (LF-INTOSC)
also provides the additional benefits of a Fail-Safe
Clock Monitor (FSCM) and Two-Speed Start-up. FSCM
provides for background monitoring of the peripheral
clock and automatic switchover in the event of its
failure. Two-Speed Start-up enables code to be exe-
cuted almost immediately on start-up, while the primary
clock source completes its start-up delays.
All of these features are enabled and configured by
setting the appropriate Configuration register bits.
28.1 Configuration Bits
Devices of the PIC18F97J94 family do not use persis-
tent memory registers to store configuration information.
The Configuration registers, CONFIG1L through
CONFIG8H, are implemented as volatile memory.
Immediately after power-up, or after a device Reset, the
microcontroller hardware automatically loads the
CONFIG1L through CONFIG8H registers with configu-
ration data stored in nonvolatile Flash program memory.
The last eight words of Flash program memory, known
as the Flash Configuration Words (FCW), are used to
store the configuration data.
Table 28-2 provides the Flash program memory, which
will be loaded into the corresponding Configuration
register.
When creating applications for these devices, users
should always specifically allocate the location of the
FCW for configuration data. This is to make certain that
program code is not stored in this address when the
code is compiled.
The four Most Significant bits (MSb) of the FCW, corre-
sponding to CONFIG1H, CONFIG2H, CONFIG3H,
CONFIG4H, CONFIG5H, CONFIG6H, CONFIG7H and
CONFIG8H, should always be programmed to ‘1111’.
This makes these FCWs appear to be NOP instructions
in the remote event that their locations are ever
executed by accident.
The four MSbs of the CONFIG1H, CONFIG2H,
CONFIG3H, CONFIG4H CONFIG5H, CONFIG6H,
CONFIG7H and CONFIG8H, registers are not imple-
mented, so writing ‘1’s to their corresponding FCW has
no effect on device operation.
To prevent inadvertent configuration changes during
code execution, the Configuration registers, CONFIG1L
through CONFIG8H, are loaded only once per power-up
or Reset cycle. User’s firmware can still change the
configuration by using self-reprogramming to modify the
contents of the FCW.
Modifying the FCW will not change the active contents
being used in the CONFIG1L through CONFIG8H
registers until after the device is reset.
PIC18F97J94 FAMILY
DS30575A-page 554 2012 Microchip Technology Inc.
TABLE 28-1: MAPPING OF THE FLASH CONFIGURATION WORDS TO THE CONFIGURATION
REGISTERS
Configuration Register (Volatile) Configuration Register Address Flash Configuration Byte Address
CONFIG1L 300000h XXXF0h
CONFIG1H 300001h XXXF1h
CONFIG2L 300002h XXXF2h
CONFIG2H 300003h XXXF3h
CONFIG3L 300004h XXXF4h
CONFIG3H 300005h XXXF5h
CONFIG4L 300006h XXXF6h
CONFIG4H 300007h XXXF7h
CONFIG5L 300008h XXXF8h
CONFIG5H 300009h XXXF9h
CONFIG6L 30000Ah XXXFAh
CONFIG6H 30000Bh XXXFBh
CONFIG7L 30000Ch XXXFCh
CONFIG7H 30000Dh XXXFDh
CONFIG8L 30000Eh XXXFEh
CONFIG8H 30000Fh XXXFFh
TABLE 28-2: CONFIGURATION BITS AND DEVICE IDs
File Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Default/
Unprogrammed
Value
300000h CONFIG1L DEBUG XINST STVREN — — — — —
111- ----
300001h CONFIG1H —
(2)
—
(2)
—
(2)
—
(2)
—
(1)
CP0 BORV BOREN
---- -111
300002h CONFIG2L IESO —CLKOEN— SOSCSEL FOSC2 FOSC1 FOSC0
1-1- 1111
300003h CONFIG2H —
(2)
—
(2)
—
(2)
—
(2)
PLLDIV3 PLLDIV2 PLLDIV1 PLLDIV0
---- 1111
300004h CONFIG3L ——FSCM1FSCM0 ——POSCMD1POSCMD0
--11 --11
300005h CONFIG3H —
(2)
—
(2)
—
(2)
—
(2)
— — — —
1111 ----
300006h CONFIG4L WPFP7 WPFP6 WPFP5 WPFP4 WPFP3 WPFP2 WPFP1 WPFP0
1111 1111
300007h CONFIG4H —
(2)
—
(2)
—
(2)
—
(2)
— WPCFG WPEND WPDIS
---- -111
300008h CONFIG5L WAIT BW ABW1 ABW0 EASHFT — CINASEL T5GSEL
1111 1-11
300009h CONFIG5H —
(2)
—
(2)
—
(2)
—
(2)
MSSPMSK1 MSSPMSK2 LS48MHZ IOL1WAY
1111 1111
30000Ah CONFIG6L WDPS3 WDPS2 WDPS1 WDPS0 WDTCLK1 WDTCLK0 WDTWIN1 WDTWIN0
1111 1111
30000Bh CONFIG6H —
(2)
—
(2)
—
(2)
—
(2)
WPSA WINDIS WDTEN1 WDTEN0
1111 1111
30000Ch CONFIG7L — — — DSBITEN DSBOREN VBTBOR — RETEN
---1 11-1
30000Dh CONFIG7H —
(2)
—
(2)
—
(2)
—
(2)
— — — —
1111 ----
30000Eh CONFIG8L DSWDTPS4 DSWDTPS3 DSWDTPS2 DSWDTPS1 DSWDTPS0 — — —
1111 1---
30000Fh CONFIG8H —
(2)
—
(2)
—
(2)
—
(2)
—— DSWDTOSC DSWDTEN
1111 --11
3FFFFEh DEVID1 DEV2 DEV1 DEV0 REV4 REV3 REV2 REV1 REV0 See Register 28-16
3FFFFFh DEVID2 DEV10 DEV9 DEV8 DEV7 DEV6 DEV5 DEV4 DEV3 See Register 28-15
Legend:
x
= unknown,
u
= unchanged,
-
= unimplemented,
q
= value depends on condition. Shaded cells are unimplemented, read as ‘
0
’.
Note 1:
This bit should always be maintained as ‘
0
’.
2:
The value of these bits in program memory should always be programmed to ‘
1
’. This ensures that the location is executed as a
NOP
if it is
accidentally executed.
2012 Microchip Technology Inc. DS30575A-page 555
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REGISTER 28-1: CONFIG1L: CONFIGURATION REGISTER 1 LOW (BYTE ADDRESS 300000h)
R/WO-1 R/WO-1 R/WO-1 U-1 U-1 U-1 U-1 U-1
DEBUG XINST STVREN — — — — —
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 DEBUG: Background Debugger Enable bit
1 = Background debugger is disabled, and RB6 and RB7 are configured as general purpose I/O pins
0 = Background debugger is enabled, and RB6 and RB7 are dedicated to In-Circuit Debug
bit 6 XINST: Extended Instruction Set Enable bit
1 = Instruction set extension and Indexed Addressing mode are enabled
0 = Instruction set extension and Indexed Addressing mode are disabled (Legacy mode)
bit 5 STVREN: Stack Overflow Reset Enable bit
1 = Reset on stack overflow/underflow is enabled
0 = Reset on stack overflow/underflow is disabled
bit 4-0 Unimplemented: Read as ‘1’
REGISTER 28-2: CONFIG1H: CONFIGURATION REGISTER 1 HIGH (BYTE ADDRESS 300001h)
U-1 U-1 U-1 U-1 U-0 R/WO-1 R/WO-1 R/WO-1
— — — — — CP0 BORV BOREN
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 Unimplemented: Read as ‘—’
bit 3 Unimplemented: Maintain as ‘0’
bit 2 CP0: Code Protection bit 0
1 = Program memory is not code-protected
0 = Program memory is code-protected (and write-protected in test modes)
bit 1 BORV: BOR Trip Point Select bit
1 = BOR trip point is 1.8V
0 = BOR trip point is 2.0V
bit 0 BOREN: Brown-out Reset Enable bit
1 = Brown-out Reset is disabled
0 = Brown-out Reset is enabled outside of Deep Sleep (BORV is always disabled in Deep Sleep)
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REGISTER 28-3: CONFIG2L: CONFIGURATION REGISTER 2 LOW (BYTE ADDRESS 300002h)
(1,2,3,4)
R/WO-1 U-1 R/WO-0 U-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1
IESO —CLKOEN— SOSCSEL FOSC2 FOSC1 FOSC0
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 IESO: Internal External Switch Over bit
1 = Internal/External Switchover mode is enabled (Two-Speed Start-up is enabled)
0 = Internal/External Switchover mode is disabled (Two-Speed Start-up is disabled)
bit 6 Unimplemented: Read as ‘1’
bit 5 CLKOEN: CLKO Enable Configuration bit
1 = CLKO output signal is active on the OSC2 pin; Primary Oscillator must be disabled or configured
for the External Clock mode (EC) for the CLKO to be active (POSCMD<1:0> = 11 or 00)
0 = CLKO output disabled
bit 4 Unimplemented: Read as ‘0’
bit 3 SOSCSEL: SOSC Selection Configuration bit
1 = Low-power SOSC circuit is selected (typical IDD of 1 μA)
0 = Digital (SCLKI) mode
bit 2-0 FOSC<2:0>: Oscillator Selection bits
000 = Fast RC Oscillator (FRC)
001 = Fast RC Oscillator with divide-by-N with PLL module (FRCDIV+PLL)
010 = Primary Oscillator (MS, HS, EC)
011 = Primary Oscillator with PLL module (MS+PLL, HS+PLL, EC+PLL)
100 = Secondary Oscillator (SOSC)
101 = Low-Power RC Oscillator (LPRC)
110 = Fast RC Oscillator (FRC) divided by 16 (500 kHz)
111 = Fast RC Oscillator with divide-by-N (FRCDIV)
Note 1: The CONFIG2L bits can only be programmed indirectly by programming the Flash Configuration Word.
2: The CONFIG2L is reset to ‘1’ only on VDD Reset; it is reloaded with the programmed value at any device
Reset.
3: Although CONFIG2L is reset to ‘1’ only on VDD Reset, these values are not used until after the actual con-
figuration values are read out and stored in the register bits. Therefore, for these bits, the Reset value has
no effect on the operation of the system.
4: Unlike other Configuration registers, the CLKOEN holding register is reset to a ‘0’ on any VDD Reset. This
prevents the CLKO pin from driving until the actual configuration values are read out and stored in the
register.
2012 Microchip Technology Inc. DS30575A-page 557
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REGISTER 28-4: CONFIG2H: CONFIGURATION REGISTER 2 HIGH (BYTE ADDRESS 300003h)(1,2)
U-1 U-1 U-1 U-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1
— — — — PLLDIV3(3)PLLDIV2(3)PLLDIV1(3)PLLDIV0(3)
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 Unimplemented: Program the corresponding Flash Configuration bit to ‘1’
bit 3-0 PLLDIV<3:0>: Frequency Multiplier Select bits(3)
Divider must be selected so as to not exceed 64 MHz output.
1111 = No PLL used; PLLEN bit is not available to user
1110 = 8x PLL is selected
1101 = 6x PLL is selected
1100 = 4x PLL is selected
1011 = Reserved; do not use
1010 = Reserved; do not use
1001 = Reserved; do not use
1000 = Reserved; do not use
0111 = 96 MHz PLL is selected; oscillator divided by 12 (48 MHz input)
0110 = 96 MHz PLL is selected; oscillator divided by 10 (40 MHz input)
0101 = 96 MHz PLL is selected; oscillator divided by 6 (24 MHz input)
0100 = 96 MHz PLL is selected; oscillator divided by 5 (20 MHz input)
0011 = 96 MHz PLL is selected; oscillator divided by 4 (16 MHz input)
0010 = 96 MHz PLL is selected; oscillator divided by 3 (12 MHz input)
0001 = 96 MHz PLL is selected; oscillator divided by 2 (8 MHz input)
0000 = 96 MHz PLL is selected; no divide – oscillator is used directly (4 MHz input)
Note 1: The CONFIG2H bits can only be programmed indirectly by programming the Flash Configuration Word.
2: The CONFIG2H is reset to ‘1’ only on VDD Reset; it is reloaded with the programmed value at any device
Reset.
3: If USB functionality is used, then this field must be set to ‘0xxx’ (i.e., 96 MHz PLL is selected).
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DS30575A-page 558 2012 Microchip Technology Inc.
REGISTER 28-5: CONFIG3L: CONFIGURATION REGISTER 3 LOW (BYTE ADDRESS 300004h)(1,2)
U-1 U-1 R/WO-1 R/WO-1 U-1 U-0 R/WO-1 R/WO-1
——FSCM1 FSCM0—— POSCMD1 POSCMD0
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-6 Unimplemented: Read as ‘1’
bit 5-4 FSCM<1:0>: Clock Switching and Monitor Selection Configuration bits
1x = Clock switching is disabled, Fail-Safe Clock Monitor is disabled
01 = Clock switching is enabled, Fail-Safe Clock Monitor is disabled
00 = Clock switching is enabled, Fail-Safe Clock Monitor is enabled
bit 3-2 Unimplemented: Read as ‘0’
bit 1-0 POSCMD<1:0>: Primary Oscillator Configuration bits
11 = Primary Oscillator is disabled
10 = HS Oscillator mode is selected (10 MHz-40 MHz)
01 = MS Oscillator mode is selected (3.5 MHz-10 MHz)
00 = External Clock mode is selected
Note 1: The CONFIG3L bits can only be programmed indirectly by programming the Flash Configuration Word.
2: The CONFIG3L is reset to ‘1’ only on VDD Reset; it is reloaded with the programmed value at any device
Reset.
2012 Microchip Technology Inc. DS30575A-page 559
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REGISTER 28-6: CONFIG4L: CONFIGURATION REGISTER 4 LOW (BYTE ADDRESS 300006h)
R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1
WPFP7 WPFP6 WPFP5 WPFP4 WPFP3 WPFP2 WPFP1 WPFP0
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 WPFP<7:0>: Write-Protect Program Flash Pages bits (valid when WPDIS = 0)
When WPEND = 0:
Write/erase protect Flash memory pages, starting at Page 0 and ending with Page WPFP<7:0>.
When WPEND = 1:
Write/erase protect Flash memory pages, starting at Page WPFP<7:0> and ending with the last page
in user Flash.
REGISTER 28-7: CONFIG4H: CONFIGURATION REGISTER 4 HIGH (BYTE ADDRESS 300007h)
U-1 U-1 U-1 U-1 U-1 R/WO-1 R/WO-1 R/WO-1
— — — — — WPCFG WPEND WPDIS
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-3 Unimplemented: Program the corresponding Flash Configuration bit to ‘1’
bit 2 WPCFG: Write/Erase Protect Last Page in User Flash bit
1 = Write/erase protection of last page is disabled, regardless of the WPFP<7:0> setting
0 = Write/erase protection of last page is enabled, regardless of the WPFP<7:0> setting
bit 1 WPEND: Write Protection End Page bit
This bit is valid when WPDIS = 0.
When WPEND = 0:
Write/erase protect Flash Memory pages, starting at Page 0 and ending with Page WPFP<7:0>.
When WPEND = 1:
Write/erase protect Flash memory pages, starting at Page WPFP<7:0> and ending with the last page
in user Flash.
bit 0 WPDIS: Write-Protect Disable bit
1 = WPFP<7:0>, WPEND and WPCFG bits are ignored
0 = WPFP<7:0>, WPEND and WPCFG bits are enabled; write-protect is active
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REGISTER 28-8: CONFIG5L: CONFIGURATION REGISTER 5 LOW (BYTE ADDRESS 300008h)
R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 U-1 R/WO-1 R/WO-1
WAIT(1)BW ABW1 ABW0 EASHFT — CINASEL T5GSEL
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 WAIT: External Bus Wait Enable bit(1)
1 = Wait selections from WAIT<1:0> (MEMCON<5:4>) are unavailable and the device will not wait
0 = Wait is programmed by WAIT<1:0> (MEMCON<5:4>)
bit 6 BW: Data Bus Width Select bit
1 = 16-Bit External Bus mode
0 = 8-Bit External Bus mode
bit 5-4 ABW<1:0>: External Memory Bus Configuration bits
00 = Extended Microcontroller Mode – 20-Bit Address mode
01 = Extended Microcontroller Mode – 16-Bit Address mode
10 = Extended Microcontroller Mode – 12-Bit Address mode
11 = Microcontroller Mode – External bus is disabled
bit 3 EASHFT: External Address Bus Shift Enable bit
1 = Address shifting is enabled – External address bus is shifted to start at 000000h
0 = Address shifting is disabled – External address bus reflects the PC value
bit 2 Unimplemented: Read as ‘0’
bit 1 CINASEL: CxINA Gate Select bit
1 = C1INA and C3INA are on their default pin locations
0 = C1INA and C3INA are all remapped to pin, RA5
bit 0 T5GSEL: TMR5 Gate Select bit
1 = TMR5 gate is driven by the T5G input
0 = TMR5 gate is driven by the T3G input
Note 1: This bit was previously referred to as ‘WAIT’, but a set condition actually indicates the case where the
EMB does not wait and the name was therefore changed to reflect this. No change in functionality or
polarity occurred, only a change in the name of the register bit.
2012 Microchip Technology Inc. DS30575A-page 561
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REGISTER 28-9: CONFIG5H: CONFIGURATION REGISTER 5 HIGH (BYTE ADDRESS 300009h)
U-1 U-1 U-1 U-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1
— — — — MSSPMSK1 MSSPMSK2 LS48MHZ IOL1WAY
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 Unimplemented: Program the corresponding Flash Configuration bit to ‘1’
bit 3 MSSPMSK1: MSSP1 7-Bit Address Masking Mode Enable bit
1 = 7-Bit Address Masking mode enable
0 = 5-Bit Address Masking mode enable
bit 2 MSSPMSK2: MSSP2 7-Bit Address Masking Mode Enable bit
1 = 7-Bit Address Masking mode enable
0 = 5-Bit Address Masking mode enable
bit 1 LS48MHZ: Low-Speed USB Clock Selection bit
1 = 48 MHz system clock is expected; divide-by-8 generates low-speed USB clock
0 = 24 MHz system clock is expected; divide-by-4 generates low-speed USB clock
bit 0 IOL1WAY: IOLOCK Bit One-Way Set Enable bit
1 = The IOLOCK bit can only be set once (provided an unlocking sequence is executed); this prevents
any possible future RP register changes
0 = The IOLOCK bit can be set and cleared as needed (provided an unlocking sequence is executed)
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DS30575A-page 562 2012 Microchip Technology Inc.
REGISTER 28-10: CONFIG6L: CONFIGURATION REGISTER 6 LOW (BYTE ADDRESS 30000Ah)
R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1
WDPS3 WDPS2 WDPS1 WDPS0 WDTCLK1 WDTCLK0 WDTWIN1 WDTWIN0
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 WDPS<3:0>: Watchdog Timer Postscale Select bits
1111 = 1:32,768
1110 = 1:16,384
1101 = 1:8,192
1100 = 1:4,096
1011 = 1:2,048
1010 = 1:1,024
1001 = 1:512
1000 = 1:256
0111 = 1:128
0110 = 1:64
0101 = 1:32
0100 = 1:16
0011 = 1:8
0010 = 1:4
0001 = 1:2
0000 = 1:1
bit 3-2 WDTCLK<1:0>: Watchdog Timer Clock Source bits
00 = Use the peripheral clock when the system clock is not INTOSC/LPRC and device is not in Sleep;
otherwise, use INTOSC/LPRC
01 = Always use SOSC
10 = Always use INTOSC/LPRC
11 = Use FRC when WINDIS = 0, system clock is not INTOSC/LPRC and device is not in Sleep;
otherwise, use INTOSC/LPRC
bit 1-0 WDTWIN<1:0>: Watchdog Timer Window Width bits
11 = 25%
10 = 37.5%
01 = 50%
00 = 75%
2012 Microchip Technology Inc. DS30575A-page 563
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REGISTER 28-11: CONFIG6H: CONFIGURATION REGISTER 6 HIGH (BYTE ADDRESS 30000Bh)
U-1 U-1 U-1 U-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1
— — — — WPSA WINDIS WDTEN1 WDTEN0
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 Unimplemented: Program the corresponding Flash Configuration bit to ‘1’
bit 3 WPSA: WDT Prescaler bit
1 = WDT prescaler ratio of 1:128
0 = WDT prescaler ratio of 1:32
bit 2 WINDIS: Windowed Watchdog Timer Disable bit
1 = Standard WDT is selected; windowed WDT is disabled
0 = Windowed WDT is enabled when executing a CLRWDT instruction while the WDT is disabled in
hardware
bit 1-0 WDTEN<1:0>: Watchdog Timer Enable bits
11 = WDT is enabled in hardware
10 = WDT is controlled with the SWDTEN bit setting
01 = WDT is enabled only while device is active and disabled in Sleep; SWDTEN bit is disabled
00 = WDT is disabled in hardware; SWDTEN bit is disabled
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REGISTER 28-12: CONFIG7L: CONFIGURATION REGISTER 7 LOW (BYTE ADDRESS 30000Ch)
U-1 U-1 U-1 R/WO-1 R/WO-1 R/WO-1 U-1 R/WO-1
— — — DSBITEN DSBOREN VBTBOR — RETEN
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘1’
bit 4 DSBITEN: DSEN Bit Enable bit
1 = Deep Sleep is controlled by the register bit, DSEN
0 = Deep Sleep operation is always disabled
bit 3 DSBOREN: Deep Sleep BOR Enable bit
1 = DSBOR is enabled in Deep Sleep
0 = DSBOR is disabled in Deep Sleep (does not affect operation in non-Deep Sleep modes)
bit 2 VBTBOR: VBAT BOR Enable bit
1 = VBAT BOR is enabled
0 = VBAT BOR is disabled
bit 1 Unimplemented: Read as ‘1’
bit 0 RETEN: Retention Voltage Regulator Control Enable bit
1 = Retention voltage regulator is disabled
0 = Retention voltage regulator is enabled; regulator power in Sleep mode is controlled by SRETEN
(RCON4<4>)
2012 Microchip Technology Inc. DS30575A-page 565
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REGISTER 28-13: CONFIG8L: CONFIGURATION REGISTER 8 LOW (BYTE ADDRESS 30000Eh)
R/WO-1 R/WO-1 R/WO-1 R/WO-1 R/WO-1 U-1 U-1 U-1
DSWDTPS4 DSWDTPS3 DSWDTPS2 DSWDTPS1 DSWDTPS0 — — —
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-3 DSWDTPS<4:0>: Deep Sleep Watchdog Timer Postscale Select bits
The DS WDT prescaler is 32; this creates an approximate base time unit of 1 ms.
11111 = 1:2^36 (25.7 days)
11110 = 1:2^35 (12.8 days)
11101 = 1:2^34 (6.4 days)
11100 = 1:2^33 (77.0 hours)
11011 = 1:2^32 (38.5 hours)
11010 = 1:2^31 (19.2 hours)
11001 = 1:2^30 (9.6 hours)
11000 = 1:2^29 (4.8 hours)
10111 = 1:2^28 (2.4 hours)
10110 = 1:2^27 (72.2 minutes)
10101 = 1:2^26 (36.1 minutes)
10100 = 1:2^25 (18.0 minutes)
10011 = 1:2^24 (9.0 minutes)
10010 = 1:2^23 (4.5 minutes)
10001 = 1:2^22 (135.3s)
10000 = 1:2^21 (67.7s)
01111 = 1:2^20 (33.825s)
01110 = 1:2^19 (16.912s)
01101 = 1:2^18 (8.456s)
01100 = 1:2^17 (4.228s)
01011 = 1:65536 (2.114s)
01010 = 1:32768 (1.057s)
01001 = 1:16384 (528.5 ms)
01000 = 1:8192 (264.3 ms)
00111 = 1:4096 (132.1 ms)
00110 = 1:2048 (66.1 ms)
00101 = 1:1024 (33 ms)
00100 = 1:512 (16.5 ms)
00011 = 1:256 (8.3 ms)
00010 = 1:128 (4.1 ms)
00001 = 1:64 (2.1 ms)
00000 = 1:32 (1 ms)
bit 2-0 Unimplemented: Read as ‘1’
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REGISTER 28-14: CONFIG8H: CONFIGURATION REGISTER 8 HIGH (BYTE ADDRESS 30000Fh)
U-1 U-1 U-1 U-1 U-1 U-1 R/WO-1 R/WO-1
— — — — — — DSWDTOSC DSWDTEN
bit 7 bit 0
Legend: P = Programmable bit WO = Write-Once bit
R = Readable bit W = Writable bit U = Unimplemented bit
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-4 Unimplemented: Program the corresponding Flash Configuration bit to ‘1’
bit 3-2 Unimplemented: Read as ‘1’
bit 1 DSWDTOSC: DSWDT Reference Clock Select bit
1 = DSWDT uses INTOSC/LPRC as the reference clock
0 = DSWDT uses T1OSC/SOSC as the reference clock
bit 0 DSWDTEN: Deep Sleep Watchdog Timer Enable bit
1 = DSWDT is enabled
0 = DSWDT is disabled
2012 Microchip Technology Inc. DS30575A-page 567
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REGISTER 28-15: DEVID2: DEVICE ID REGISTER 2 FOR THE PIC18F97J94
RRRRRRRR
DEV10 DEV9 DEV8 DEV7 DEV6 DEV5 DEV4 DEV3
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 DEV<10:3>: Device ID bits
These bits are used with the DEV<2:0> bits in the Device ID Register 1 to identify the part number.
REGISTER 28-16: DEVID1: DEVICE ID REGISTER 1 FOR THE PIC18F97J94
RRRRRRRR
DEV2 DEV1 DEV0 REV4 REV3 REV2 REV1 REV0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 DEV<2:0>: Device ID bits
These bits are used with the DEV<10:3> bits in the Device ID Register 2 to identify the part number:
0110 0010 101 = PIC18F97J94
0110 0010 110 = PIC18F96J99
0110 0010 111 = PIC18F96J94
0110 0011 000 = PIC18F95J94
0110 0011 001 = PIC18F87J94
0110 0011 010 = PIC18F86J99
0110 0011 011 = PIC18F86J94
0110 0011 100 = PIC18F85J94
0110 0011 101 = PIC18F67J94
0110 0011 110 = PIC18F66J99
0110 0011 111 = PIC18F66J94
0110 0100 000 = PIC18F65J94
bit 4-0 REV<4:0>: Revision ID bits
These bits are used to indicate the device revision.
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28.2 Watchdog Timer (WDT)
For the PIC18F97J94 family of devices, the WDT is
driven by the LF-INTOSC source. When the WDT is
enabled, the clock source is also enabled. The nominal
WDT period is 4 ms and has the same stability as the
LF-INTOSC Oscillator.
The 4 ms period of the WDT is multiplied by a 16-bit
postscaler. Any output of the WDT postscaler is
selected by a multiplexer, controlled by bits in
Configuration Register 2H. Available periods range
from 4 ms to 4,194 seconds (about one hour). The
WDT and postscaler are cleared when any of the
following events occur: a SLEEP or CLRWDT instruction
is executed, the IRCFx bits (OSCCON3<2:0>) are
changed or a clock failure has occurred.
28.2.1 WINDOWED OPERATION
The Watchdog Timer has an optional Fixed Window
mode of operation. In this Windowed mode, CLRWDT
instructions can only reset the WDT during the last 1/4
of the programmed WDT period. A CLRWDT instruction
executed before that window causes a WDT Reset,
similar to a WDT time-out.
Windowed WDT mode is enabled by programming the
WINDIS Configuration bit (CONFIG6H<2>) to ‘0’.
The WDT can be operated in one of four modes, as
determined by WDTEN<1:0> (CONFIG6H<1:0>. The
four modes are:
•WDT Enabled
• WDT Disabled
• WDT under Software Control,
SWDTEN (RCON2<5>)
•WDT:
- Enabled during normal operation
- Disabled during Sleep
FIGURE 28-1: WDT BLOCK DIAGRAM
Note 1: The CLRWDT and SLEEP instructions
clear the WDT and postscaler counts
when executed.
2: Changing the setting of the IRCFx bits
(OSCCON3<2:0>) clear the WDT and
postscaler counts.
3: When a CLRWDT instruction is executed,
the postscaler count will be cleared.
INTOSC Source
WDT
Reset
WDT Counter
Enable WDT
WDTPS<3:0>
CLRWDT
4
Reset
All Device Resets
Sleep
128
Change on IRCFx bits
INTOSC Source
Enable WDT
SWDTEN
WDTEN<1:0>
WDTEN1
WDTEN0
WDT Enabled,
SWDTEN Disabled
WDT Controlled with
SWDTEN bit Setting
WDT Enabled only while
Device Active, Disabled
WDT Disabled in Hardware,
SWDTEN Disabled
Wake-up from
Power-Managed
Modes
Programmable Postscaler
1:1 to 1:1,048,576
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28.2.2 CONTROL REGISTER
Register 28-17 shows the RCON2 register. This is a
readable and writable register which contains a control
bit that allows software to override the WDT Enable
Configuration bit, but only if the Configuration bit has
disabled the WDT.
REGISTER 28-17: RCON2: RESET CONTROL REGISTER 2
R/W, HS-0 U-0 R/W-0 U-0 U-0 U-0 U-0 U-0
EXTR(1)—SWDTEN
(2)— — — — —
bit 7 bit 0
Legend:
HS = Hardware Settable bit
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 EXTR: External Reset (MCLR) Pin bit(1)
1 = A Master Clear (pin) Reset has occurred
0 = A Master Clear (pin) Reset has not occurred
bit 6 Unimplemented: Read as ‘0’
bit 5 SWDTEN: Software Controlled Watchdog Timer Enable bit(2)
1 = Watchdog Timer is on
0 = Watchdog Timer is off
bit 4-0 Unimplemented: Read as ‘0’
Note 1: This bit is set in hardware; it can be cleared in software.
2: This bit has no effect unless the Configuration bits, WDTEN<1:0> = 10.
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28.3 Two-Speed Start-up
The Two-Speed Start-up feature helps to minimize the
latency period from oscillator start-up to code execution
by allowing the microcontroller to use the INTOSC
(LF-INTOSC, MF-INTOSC, HF-INTOSC) Oscillator as a
clock source until the primary clock source is available.
It is enabled by setting the IESO Configuration bit.
Two-Speed Start-up should be enabled only if the Pri-
mary Oscillator mode is LP, MS or HS (Crystal-Based
modes). Other sources do not require an OST start-up
delay; for these, Two-Speed Start-up should be
disabled.
When enabled, Resets and wake-ups from Sleep mode
cause the device to configure itself to run from the
internal oscillator block as the clock source, following the
time-out of the Power-up Timer (PWRT) after a Power-
on Reset is enabled. This allows almost immediate code
execution while the Primary Oscillator starts and the
OST is running. Once the OST times out, the device
automatically switches to PRI_RUN mode.
To use a higher clock speed on wake-up, the INTOSC or
postscaler clock sources can be selected to provide a
higher clock speed by setting bits, IRCF<2:0>,
immediately after Reset. For wake-ups from Sleep, the
INTOSC or postscaler clock sources can be selected by
setting the IRCF2:0> bits prior to entering Sleep mode.
In all other power-managed modes, Two-Speed Start-up
is not used. The device will be clocked by the cur-
rently selected clock source until the primary clock
source becomes available. The setting of the IESO
Configuration bit is ignored.
28.3.1 SPECIAL CONSIDERATIONS FOR
USING TWO-SPEED START-UP
While using the INTOSC Oscillator in Two-Speed Start-
up, the device still obeys the normal command
sequences for entering power-managed modes,
including multiple SLEEP instructions. In practice, this
means that user code can change the NOSC<2:0> bit
settings or issue SLEEP instructions before the OST
times out. This would allow an application to briefly
wake-up, perform routine “housekeeping” tasks and
return to Sleep before the device starts to operate from
the Primary Oscillator.
User code can also check if the primary clock source is
currently providing the device clocking by checking the
status of the COSC<2:0> bits (OSCCON<2:0>). If the
bit is set, the Primary Oscillator is providing the clock.
Otherwise, the internal oscillator block is providing the
clock during wake-up from Reset or Sleep mode.
FIGURE 28-2: TIMING TRANSITION FOR TWO-SPEED START-UP (INTOSC TO HSPLL)
Q1 Q3 Q4
OSC1
Peripheral
Program PC PC + 2
INTOSC
PLL Clock
Q1
PC + 6
Q2
Output
Q3 Q4 Q1
CPU Clock
PC + 4
Clock
Counter
Q2 Q2 Q3
Note 1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
2: Clock transition typically occurs within 2-4 TOSC.
Wake from Interrupt Event
TPLL(1)
12 n-1n
Clock
OST Expired
Transition(2)
Multiplexer
TOST(1)
2012 Microchip Technology Inc. DS30575A-page 571
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28.4 Fail-Safe Clock Monitor
The Fail-Safe Clock Monitor (FSCM) allows the
microcontroller to continue operation in the event of
an external oscillator failure by automatically switch-
ing the device clock to the internal oscillator block.
The FSCM function is enabled by clearing the FSCMx
Configuration bits.
When FSCM is enabled, the LF-INTOSC Oscillator
runs at all times to monitor clocks to peripherals and
provides a backup clock in the event of a clock failure.
Clock monitoring (shown in Figure 28-3) is accom-
plished by creating a sample clock signal, which is the
output from the LF-INTOSC, divided by 64. This allows
ample time between FSCM sample clocks for a periph-
eral clock edge to occur. The peripheral device clock
and the sample clock are presented as inputs to the
Clock Monitor (CM) latch. The CM is set on the falling
edge of the device clock source, but cleared on the
rising edge of the sample clock.
FIGURE 28-3: FSCM BLOCK DIAGRAM
Clock failure is tested for on the falling edge of the
sample clock. If a sample clock falling edge occurs
while CM is still set, a clock failure has been detected
(Figure 28-4). This causes the following:
• The FSCM generates an oscillator fail interrupt by
setting bit, OSCFIF (PIR2<7>)
• The device clock source switches to the internal
oscillator block (OSCCON is not updated to show
the current clock source – this is the fail-safe
condition)
•The WDT is reset
During switchover, the postscaler frequency from the
internal oscillator block may not be sufficiently stable for
timing-sensitive applications. In these cases, it may be
desirable to select another clock configuration and enter
an alternate power-managed mode. This can be done to
attempt a partial recovery or execute a controlled shut-
down. See Section 28.3.1 “Special Considerations
for Using Two-Speed Start-up” for more details.
To use a higher clock speed on wake-up, the INTOSC
or postscaler clock sources can be selected to provide
a higher clock speed by setting bits, IRCF<2:0>,
immediately after Reset. For wake-ups from Sleep, the
INTOSC or postscaler clock sources can be selected
by setting the IRCF<2:0> bits prior to entering Sleep
mode.
The FSCM will detect only failures of the primary or
secondary clock sources. If the internal oscillator block
fails, no failure would be detected nor would any action
be possible.
28.4.1 FSCM AND THE WATCHDOG TIMER
Both the FSCM and the WDT are clocked by the
INTOSC Oscillator. Since the WDT operates with a
separate divider and counter, disabling the WDT has
no effect on the operation of the INTOSC Oscillator
when the FSCM is enabled.
As already noted, the clock source is switched to the
INTOSC clock when a clock failure is detected.
Depending on the frequency selected by the
IRCF<2:0> bits, this may mean a substantial change in
the speed of code execution. If the WDT is enabled
with a small prescale value, a decrease in clock speed
allows a WDT time-out to occur and a subsequent
device Reset. For this reason, Fail-Safe Clock events
also reset the WDT and postscaler, allowing it to start
timing from when execution speed was changed and
decreasing the likelihood of an erroneous time-out.
28.4.2 EXITING FAIL-SAFE OPERATION
The Fail-Safe condition is terminated by either a device
Reset or by entering a power-managed mode. On
Reset, the controller starts the primary clock source,
specified in Configuration Register 1H (with any
required start-up delays that are required for the
oscillator mode, such as the OST or PLL timer). The
INTOSC multiplexer provides the device clock until the
primary clock source becomes ready (similar to a Two-
Speed Start-up). The clock source is then switched to
the primary clock automatically after an OST. The Fail-
Safe Clock Monitor then resumes monitoring the
peripheral clock.
The primary clock source may never become ready
during start-up. In this case, operation is clocked by the
INTOSC multiplexer. The OSCCON register will remain
in its Reset state until a power-managed mode is
entered.
Peripheral
INTOSC ÷ 64
S
C
Q
(32 s) 488 Hz
(2.048 ms)
Clock Monitor
Latch (CM)
(edge-triggered)
Clock
Failure
Detected
Source
Clock
Q
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FIGURE 28-4: FSCM TIMING DIAGRAM
28.4.3 FSCM INTERRUPTS IN
POWER-MANAGED MODES
By entering a power-managed mode, the clock multi-
plexer selects the clock source selected by the OSCCON
register. Fail-Safe Clock Monitoring of the power-
managed clock source resumes in the power-managed
mode.
If an oscillator failure occurs during power-managed
operation, the subsequent events depend on whether
or not the oscillator failure interrupt is enabled. If
enabled (OSCFIF = 1), code execution will be clocked
by the INTOSC multiplexer. An automatic transition
back to the failed clock source will not occur.
If the interrupt is disabled, subsequent interrupts while
in Idle mode will cause the CPU to begin executing
instructions while being clocked by the INTOSC
source.
28.4.4 POR OR WAKE FROM SLEEP
The FSCM is designed to detect oscillator failure at any
point after the device has exited Power-on Reset
(POR) or low-power Sleep mode. When the primary
device clock is EC, RC or INTOSC modes, monitoring
can begin immediately following these events.
For oscillator modes involving a crystal or resonator
(HS, HSPLL, LP or MS), the situation is somewhat
different. Since the oscillator may require a start-up
time considerably longer than the FCSM sample clock
time, a false clock failure may be detected. To prevent
this, the internal oscillator block is automatically config-
ured as the device clock and functions until the primary
clock is stable (when the OST and PLL timers have
timed out).
This is identical to Two-Speed Start-up mode. Once the
primary clock is stable, the INTOSC returns to its role
as the FSCM source.
As noted in Section 28.3.1 “Special Considerations
for Using Two-Speed Start-up”, it is also possible to
select another clock configuration and enter an
alternate power-managed mode while waiting for the
primary clock to become stable. When the new power-
managed mode is selected, the primary clock is
disabled.
OSCFIF
CM Output
Device
Clock
Output
Sample Clock
Failure
Detected
Oscillator
Failure
Note: The device clock is normally at a much higher frequency than the sample clock. The relative frequencies in this
example have been chosen for clarity.
(Q)
CM Test CM Test CM Test
Note: The same logic that prevents false oscilla-
tor failure interrupts on POR, or wake from
Sleep, also prevents the detection of the
oscillator’s failure to start at all following
these events. This is avoided by an OST
time-out condition and by using a timing
routine to determine if the oscillator is tak-
ing too long to start. Even so, no oscillator
failure interrupt will be flagged.
2012 Microchip Technology Inc. DS30575A-page 573
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28.4.5 PROGRAM VERIFICATION AND
CODE PROTECTION
For all devices in the PIC18F97J94 family of devices,
the on-chip program memory space is treated as a
single block. Code protection for this block is controlled
by one Configuration bit, CP0. This bit inhibits external
reads and writes to the program memory space. It has
no direct effect in normal execution mode.
28.4.6 CONFIGURATION REGISTER
PROTECTION
The Configuration registers are protected against
untoward changes or reads in two ways. The primary
protection is the write-once feature of the Configuration
bits, which prevents reconfiguration once the bit has
been programmed during a power cycle. To safeguard
against unpredictable events, Configuration bit
changes, resulting from individual cell level disruptions
(such as ESD events), will cause a parity error and
trigger a device Reset. This is seen by the user as a
Configuration Mismatch (CM) Reset.
The data for the Configuration registers is derived from
the FCW in program memory. When the CP0 bit is set,
the source data for device configuration is also
protected as a consequence.
28.5 In-Circuit Serial Programming
The PIC18F97J94 family of devices can be serially
programmed while in the end application circuit. This is
simply done with two lines for clock and data and three
other lines for power, ground and the programming
voltage. This allows customers to manufacture boards
with unprogrammed devices and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware or a custom
firmware to be programmed.
For the various programming modes, see the
programming specification
28.6 In-Circuit Debugger
When the DEBUG Configuration bit is programmed to
a ‘0’, the In-Circuit Debugger functionality is enabled.
This function allows simple debugging functions when
used with MPLAB® IDE. When the microcontroller has
this feature enabled, some resources are not available
for general use. Ta b l e 2 8 - 3 shows which resources are
required by the background debugger.
TABLE 28-3: DEBUGGER RESOURCES
To use the In-Circuit Debugger function of the microcon-
troller, the design must implement In-Circuit Serial
Programming connections to MCLR, VDD, VSS, RB7 and
RB6. This will interface to the In-Circuit Debugger
module available from Microchip or one of the third-party
development tool companies.
I/O Pins: RB6, RB7
Stack: Two levels
Program Memory: 512 bytes
Data Memory: 10 bytes
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NOTES:
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29.0 INSTRUCTION SET SUMMARY
The PIC18F97J94 family of devices incorporates the
standard set of 75 PIC18 core instructions, as well as
an extended set of 8 new instructions for the optimiza-
tion of code that is recursive or that utilizes a software
stack. The extended set is discussed later in this
section.
29.1 Standard Instruction Set
The standard PIC18 MCU instruction set adds many
enhancements to the previous PIC® MCU instruction
sets, while maintaining an easy migration from these
PIC MCU instruction sets. Most instructions are a
single program memory word (16 bits), but there are
four instructions that require two program memory
locations.
Each single-word instruction is a 16-bit word divided
into an opcode, which specifies the instruction type and
one or more operands, which further specify the
operation of the instruction.
The instruction set is highly orthogonal and is grouped
into four basic categories:
•Byte-oriented operations
•Bit-oriented operations
•Literal operations
•Control operations
The PIC18 instruction set summary in Table 29-2 lists
byte-oriented, bit-oriented, literal and control
operations. Table 29-1 shows the opcode field
descriptions.
Most byte-oriented instructions have three operands:
1. The file register (specified by ‘f’)
2. The destination of the result (specified by ‘d’)
3. The accessed memory (specified by ‘a’)
The file register designator, ‘f’, specifies which file reg-
ister is to be used by the instruction. The destination
designator, ‘d’, specifies where the result of the
operation is to be placed. If ‘d’ is zero, the result is
placed in the WREG register. If ‘d’ is one, the result is
placed in the file register specified in the instruction.
All bit-oriented instructions have three operands:
1. The file register (specified by ‘f’)
2. The bit in the file register (specified by ‘b’)
3. The accessed memory (specified by ‘a’)
The bit field designator, ‘b’, selects the number of the bit
affected by the operation, while the file register desig-
nator, ‘f’, represents the number of the file in which the
bit is located.
The literal instructions may use some of the following
operands:
• A literal value to be loaded into a file register
(specified by ‘k’)
• The desired FSR register to load the literal value
into (specified by ‘f’)
• No operand required
(specified by ‘—’)
The control instructions may use some of the following
operands:
• A program memory address (specified by ‘n’)
• The mode of the CALL or RETURN instructions
(specified by ‘s’)
• The mode of the table read and table write
instructions (specified by ‘m’)
• No operand required
(specified by ‘—’)
All instructions are a single word, except for four
double-word instructions. These instructions were
made double-word to contain the required information
in 32 bits. In the second word, the 4 MSbs are ‘1’s. If
this second word is executed as an instruction (by
itself), it will execute as a NOP.
All single-word instructions are executed in a single
instruction cycle, unless a conditional test is true or the
Program Counter is changed as a result of the instruc-
tion. In these cases, the execution takes two instruction
cycles with the additional instruction cycle(s) executed
as a NOP.
The double-word instructions execute in two instruction
cycles.
One instruction cycle consists of four oscillator periods.
Thus, for an oscillator frequency of 4 MHz, the normal
instruction execution time is 1 s. If a conditional test is
true, or the Program Counter is changed as a result of
an instruction, the instruction execution time is 2 s.
Two-word branch instructions (if true) would take 3 s.
Figure 29-1 shows the general formats that the instruc-
tions can have. All examples use the convention ‘nnh’
to represent a hexadecimal number.
The Instruction Set Summary, shown in Tab l e 29-2,
lists the standard instructions recognized by the
Microchip MPASMTM Assembler.
Section 29.1.1 “Standard Instruction Set” provides
a description of each instruction.
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DS30575A-page 576 2012 Microchip Technology Inc.
TABLE 29-1: OPCODE FIELD DESCRIPTIONS
Field Description
aRAM access bit:
a = 0: RAM location in Access RAM (BSR register is ignored)
a = 1: RAM bank is specified by BSR register
bbb Bit address within an 8-bit file register (0 to 7).
BSR Bank Select Register. Used to select the current RAM bank.
C, DC, Z, OV, N ALU Status bits: Carry, Digit Carry, Zero, Overflow, Negative.
dDestination select bit:
d = 0: store result in WREG
d = 1: store result in file register f
dest Destination: either the WREG register or the specified register file location.
f8-bit register file address (00h to FFh), or 2-bit FSR designator (0h to 3h).
fs12-bit register file address (000h to FFFh). This is the source address.
fd12-bit register file address (000h to FFFh). This is the destination address.
GIE Global Interrupt Enable bit.
kLiteral field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value).
label Label name.
mm The mode of the TBLPTR register for the table read and table write instructions.
Only used with table read and table write instructions:
*No Change to register (such as TBLPTR with table reads and writes)
*+ Post-Increment register (such as TBLPTR with table reads and writes)
*- Post-Decrement register (such as TBLPTR with table reads and writes)
+* Pre-Increment register (such as TBLPTR with table reads and writes)
nThe relative address (2’s complement number) for relative branch instructions or the direct address for
Call/Branch and Return instructions.
PC Program Counter.
PCL Program Counter Low Byte.
PCH Program Counter High Byte.
PCLATH Program Counter High Byte Latch.
PCLATU Program Counter Upper Byte Latch.
PD Power-Down bit.
PRODH Product of Multiply High Byte.
PRODL Product of Multiply Low Byte.
sFast Call/Return mode select bit:
s = 0: do not update into/from shadow registers
s = 1: certain registers loaded into/from shadow registers (Fast mode)
TBLPTR 21-bit Table Pointer (points to a Program Memory location).
TABLAT 8-bit Table Latch.
TO Time-out bit.
TOS Top-of-Stack.
uUnused or Unchanged.
WDT Watchdog Timer.
WREG Working register (accumulator).
xDon’t care (‘0’ or ‘1’). The assembler will generate code with x = 0. It is the recommended form of use for
compatibility with all Microchip software tools.
zs7-bit offset value for Indirect Addressing of register files (source).
zd7-bit offset value for Indirect Addressing of register files (destination).
{ } Optional argument.
[text] Indicates an Indexed Address.
(text) The contents of text.
[expr]<n> Specifies bit n of the register indicated by the pointer expr.
Assigned to.
< > Register bit field.
In the set of.
italics User-defined term (font is Courier New).
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FIGURE 29-1: GENERAL FORMAT FOR INSTRUCTIONS
Byte-oriented file register operations
15 10 9 8 7 0
d = 0 for result destination to be WREG register
OPCODE d a f (FILE #)
d = 1 for result destination to be file register (f)
a = 0 to force Access Bank
Bit-oriented file register operations
15 12 11 9 8 7 0
OPCODE b (BIT #) a f (FILE #)
b = 3-bit position of bit in file register (f)
Literal operations
15 8 7 0
OPCODE k (literal)
k = 8-bit immediate value
Byte to Byte move operations (2-word)
15 12 11 0
OPCODE f (Source FILE #)
CALL, GOTO and Branch operations
15 8 7 0
OPCODE n<7:0> (literal)
n = 20-bit immediate value
a = 1 for BSR to select bank
f = 8-bit file register address
a = 0 to force Access Bank
a = 1 for BSR to select bank
f = 8-bit file register address
15 12 11 0
1111 n<19:8> (literal)
15 12 11 0
1111 f (Destination FILE #)
f = 12-bit file register address
Control operations
Example Instruction
ADDWF MYREG, W, B
MOVFF MYREG1, MYREG2
BSF MYREG, bit, B
MOVLW 7Fh
GOTO Label
15 8 7 0
OPCODE S n<7:0> (literal)
15 12 11 0
1111 n<19:8> (literal)
CALL MYFUNC
15 11 10 0
OPCODE n<10:0> (literal)
S = Fast bit
BRA MYFUNC
15 8 7 0
OPCODE n<7:0> (literal) BC MYFUNC
PIC18F97J94 FAMILY
DS30575A-page 578 2012 Microchip Technology Inc.
TABLE 29-2: PIC18F97J94 FAMILY INSTRUCTION SET
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
BYTE-ORIENTED OPERATIONS
ADDWF
ADDWFC
ANDWF
CLRF
COMF
CPFSEQ
CPFSGT
CPFSLT
DECF
DECFSZ
DCFSNZ
INCF
INCFSZ
INFSNZ
IORWF
MOVF
MOVFF
MOVWF
MULWF
NEGF
RLCF
RLNCF
RRCF
RRNCF
SETF
SUBFWB
SUBWF
SUBWFB
SWAPF
TSTFSZ
XORWF
f, d, a
f, d, a
f, d, a
f, a
f, d, a
f, a
f, a
f, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
fs, fd
f, a
f, a
f, a
f, d, a
f, d, a
f, d, a
f, d, a
f, a
f, d, a
f, d, a
f, d, a
f, d, a
f, a
f, d, a
Add WREG and f
Add WREG and Carry bit to f
AND WREG with f
Clear f
Complement f
Compare f with WREG, Skip =
Compare f with WREG, Skip >
Compare f with WREG, Skip <
Decrement f
Decrement f, Skip if 0
Decrement f, Skip if Not 0
Increment f
Increment f, Skip if 0
Increment f, Skip if Not 0
Inclusive OR WREG with f
Move f
Move fs (source) to 1st word
fd (destination) 2nd word
Move WREG to f
Multiply WREG with f
Negate f
Rotate Left f through Carry
Rotate Left f (No Carry)
Rotate Right f through Carry
Rotate Right f (No Carry)
Set f
Subtract f from WREG with
Borrow
Subtract WREG from f
Subtract WREG from f with
Borrow
Swap Nibbles in f
Test f, Skip if 0
Exclusive OR WREG with f
1
1
1
1
1
1 (2 or 3)
1 (2 or 3)
1 (2 or 3)
1
1 (2 or 3)
1 (2 or 3)
1
1 (2 or 3)
1 (2 or 3)
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1 (2 or 3)
1
0010
0010
0001
0110
0001
0110
0110
0110
0000
0010
0100
0010
0011
0100
0001
0101
1100
1111
0110
0000
0110
0011
0100
0011
0100
0110
0101
0101
0101
0011
0110
0001
01da
00da
01da
101a
11da
001a
010a
000a
01da
11da
11da
10da
11da
10da
00da
00da
ffff
ffff
111a
001a
110a
01da
01da
00da
00da
100a
01da
11da
10da
10da
011a
10da
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
C, DC, Z, OV, N
C, DC, Z, OV, N
Z, N
Z
Z, N
None
None
None
C, DC, Z, OV, N
None
None
C, DC, Z, OV, N
None
None
Z, N
Z, N
None
None
None
C, DC, Z, OV, N
C, Z, N
Z, N
C, Z, N
Z, N
None
C, DC, Z, OV, N
C, DC, Z, OV, N
C, DC, Z, OV, N
None
None
Z, N
1, 2
1, 2
1, 2
2
1, 2
4
4
1, 2
1, 2, 3, 4
1, 2, 3, 4
1, 2
1, 2, 3, 4
4
1, 2
1, 2
1
1, 2
1, 2
1, 2
1, 2
4
1, 2
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be
that value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input
and is driven low by an external device, the data will be written back with a ‘0’.
2: If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be
cleared if assigned.
3: If the Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The
second cycle is executed as a NOP.
4: Some instructions are two-word instructions. The second word of these instructions will be executed as a
NOP unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures
that all program memory locations have a valid instruction.
2012 Microchip Technology Inc. DS30575A-page 579
PIC18F97J94 FAMILY
BIT-ORIENTED OPERATIONS
BCF
BSF
BTFSC
BTFSS
BTG
f, b, a
f, b, a
f, b, a
f, b, a
f, b, a
Bit Clear f
Bit Set f
Bit Test f, Skip if Clear
Bit Test f, Skip if Set
Bit Toggle f
1
1
1 (2 or 3)
1 (2 or 3)
1
1001
1000
1011
1010
0111
bbba
bbba
bbba
bbba
bbba
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
None
None
None
None
None
1, 2
1, 2
3, 4
3, 4
1, 2
CONTROL OPERATIONS
BC
BN
BNC
BNN
BNOV
BNZ
BOV
BRA
BZ
CALL
CLRWDT
DAW
GOTO
NOP
NOP
POP
PUSH
RCALL
RESET
RETFIE
RETLW
RETURN
SLEEP
n
n
n
n
n
n
n
n
n
n, s
—
—
n
—
—
—
—
n
s
k
s
—
Branch if Carry
Branch if Negative
Branch if Not Carry
Branch if Not Negative
Branch if Not Overflow
Branch if Not Zero
Branch if Overflow
Branch Unconditionally
Branch if Zero
Call Subroutine 1st word
2nd word
Clear Watchdog Timer
Decimal Adjust WREG
Go to Address 1st word
2nd word
No Operation
No Operation
Pop Top of Return Stack (TOS)
Push Top of Return Stack (TOS)
Relative Call
Software Device Reset
Return from Interrupt Enable
Return with Literal in WREG
Return from Subroutine
Go into Standby mode
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
2
1 (2)
2
1
1
2
1
1
1
1
2
1
2
2
2
1
1110
1110
1110
1110
1110
1110
1110
1101
1110
1110
1111
0000
0000
1110
1111
0000
1111
0000
0000
1101
0000
0000
0000
0000
0000
0010
0110
0011
0111
0101
0001
0100
0nnn
0000
110s
kkkk
0000
0000
1111
kkkk
0000
xxxx
0000
0000
1nnn
0000
0000
1100
0000
0000
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
kkkk
kkkk
0000
0000
kkkk
kkkk
0000
xxxx
0000
0000
nnnn
1111
0001
kkkk
0001
0000
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
kkkk
kkkk
0100
0111
kkkk
kkkk
0000
xxxx
0110
0101
nnnn
1111
000s
kkkk
001s
0011
None
None
None
None
None
None
None
None
None
None
TO, PD
C
None
None
None
None
None
None
All
GIE/GIEH,
PEIE/GIEL
None
None
TO, PD
4
TABLE 29-2: PIC18F97J94 FAMILY INSTRUCTION SET (CONTINUED)
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be
that value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input
and is driven low by an external device, the data will be written back with a ‘0’.
2: If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be
cleared if assigned.
3: If the Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The
second cycle is executed as a NOP.
4: Some instructions are two-word instructions. The second word of these instructions will be executed as a
NOP unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures
that all program memory locations have a valid instruction.
PIC18F97J94 FAMILY
DS30575A-page 580 2012 Microchip Technology Inc.
LITERAL OPERATIONS
ADDLW
ANDLW
IORLW
LFSR
MOVLB
MOVLW
MULLW
RETLW
SUBLW
XORLW
k
k
k
f, k
k
k
k
k
k
k
Add Literal and WREG
AND Literal with WREG
Inclusive OR Literal with WREG
Move literal (12-bit) 2nd word
to FSR(f) 1st word
Move Literal to BSR<3:0>
Move Literal to WREG
Multiply Literal with WREG
Return with Literal in WREG
Subtract WREG from Literal
Exclusive OR Literal with WREG
1
1
1
2
1
1
1
2
1
1
0000
0000
0000
1110
1111
0000
0000
0000
0000
0000
0000
1111
1011
1001
1110
0000
0001
1110
1101
1100
1000
1010
kkkk
kkkk
kkkk
00ff
kkkk
0000
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
C, DC, Z, OV, N
Z, N
Z, N
None
None
None
None
None
C, DC, Z, OV, N
Z, N
DATA MEMORY PROGRAM MEMORY OPERATIONS
TBLRD*
TBLRD*+
TBLRD*-
TBLRD+*
TBLWT*
TBLWT*+
TBLWT*-
TBLWT+*
Table Read
Table Read with Post-Increment
Table Read with Post-Decrement
Table Read with Pre-Increment
Table Write
Table Write with Post-Increment
Table Write with Post-Decrement
Table Write with Pre-Increment
2
2
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
1000
1001
1010
1011
1100
1101
1110
1111
None
None
None
None
None
None
None
None
TABLE 29-2: PIC18F97J94 FAMILY INSTRUCTION SET (CONTINUED)
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected Notes
MSb LSb
Note 1: When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be
that value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input
and is driven low by an external device, the data will be written back with a ‘0’.
2: If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be
cleared if assigned.
3: If the Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The
second cycle is executed as a NOP.
4: Some instructions are two-word instructions. The second word of these instructions will be executed as a
NOP unless the first word of the instruction retrieves the information embedded in these 16 bits. This ensures
that all program memory locations have a valid instruction.
2012 Microchip Technology Inc. DS30575A-page 581
PIC18F97J94 FAMILY
29.1.1 STANDARD INSTRUCTION SET
ADDLW ADD Literal to W
Syntax: ADDLW k
Operands: 0 k 255
Operation: (W) + k W
Status Affected: N, OV, C, DC, Z
Encoding: 0000 1111 kkkk kkkk
Description: The contents of W are added to the
8-bit literal ‘k’ and the result is placed in
W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
Write to
W
Example: ADDLW 15h
Before Instruction
W = 10h
After Instruction
W = 25h
ADDWF ADD W to f
Syntax: ADDWF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (W) + (f) dest
Status Affected: N, OV, C, DC, Z
Encoding: 0010 01da ffff ffff
Description: Add W to register ‘f’. If ‘d’ is ‘0’, the
result is stored in W. If ‘d’ is ‘1’, the
result is stored back in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: ADDWF REG, 0, 0
Before Instruction
W = 17h
REG = 0C2h
After Instruction
W = 0D9h
REG = 0C2h
Note: All PIC18 instructions may take an optional label argument preceding the instruction mnemonic for use in
symbolic addressing. If a label is used, the instruction format then becomes: {label} instruction argument(s).
PIC18F97J94 FAMILY
DS30575A-page 582 2012 Microchip Technology Inc.
ADDWFC ADD W and Carry bit to f
Syntax: ADDWFC f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (W) + (f) + (C) dest
Status Affected: N,OV, C, DC, Z
Encoding: 0010 00da ffff ffff
Description: Add W, the Carry flag and data memory
location ‘f’. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed in data memory location ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: ADDWFC REG, 0, 1
Before Instruction
Carry bit = 1
REG = 02h
W=4Dh
After Instruction
Carry bit = 0
REG = 02h
W = 50h
ANDLW AND Literal with W
Syntax: ANDLW k
Operands: 0 k 255
Operation: (W) .AND. k W
Status Affected: N, Z
Encoding: 0000 1011 kkkk kkkk
Description: The contents of W are ANDed with the
8-bit literal ‘k’. The result is placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
‘k’
Process
Data
Write to
W
Example: ANDLW 05Fh
Before Instruction
W=A3h
After Instruction
W = 03h
2012 Microchip Technology Inc. DS30575A-page 583
PIC18F97J94 FAMILY
ANDWF AND W with f
Syntax: ANDWF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (W) .AND. (f) dest
Status Affected: N, Z
Encoding: 0001 01da ffff ffff
Description: The contents of W are ANDed with
register ‘f’. If ‘d’ is ‘0’, the result is stored
in W. If ‘d’ is ‘1’, the result is stored back
in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: ANDWF REG, 0, 0
Before Instruction
W = 17h
REG = C2h
After Instruction
W = 02h
REG = C2h
BC Branch if Carry
Syntax: BC n
Operands: -128 n 127
Operation: if Carry bit is ‘1’,
(PC) + 2 + 2n PC
Status Affected: None
Encoding: 1110 0010 nnnn nnnn
Description: If the Carry bit is ’1’, then the program
will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
No
operation
Example: HERE BC 5
Before Instruction
PC = address (HERE)
After Instruction
If Carry = 1;
PC = address (HERE + 12)
If Carry = 0;
PC = address (HERE + 2)
PIC18F97J94 FAMILY
DS30575A-page 584 2012 Microchip Technology Inc.
BCF Bit Clear f
Syntax: BCF f, b {,a}
Operands: 0 f 255
0 b 7
a [0,1]
Operation: 0 f<b>
Status Affected: None
Encoding: 1001 bbba ffff ffff
Description: Bit ‘b’ in register ‘f’ is cleared.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
register ‘f’
Example: BCF FLAG_REG, 7, 0
Before Instruction
FLAG_REG = C7h
After Instruction
FLAG_REG = 47h
BN Branch if Negative
Syntax: BN n
Operands: -128 n 127
Operation: if Negative bit is ‘1’,
(PC) + 2 + 2n PC
Status Affected: None
Encoding: 1110 0110 nnnn nnnn
Description: If the Negative bit is ‘1’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
No
operation
Example: HERE BN Jump
Before Instruction
PC = address (HERE)
After Instruction
If Negative = 1;
PC = address (Jump)
If Negative = 0;
PC = address (HERE + 2)
2012 Microchip Technology Inc. DS30575A-page 585
PIC18F97J94 FAMILY
BNC Branch if Not Carry
Syntax: BNC n
Operands: -128 n 127
Operation: if Carry bit is ‘0’,
(PC) + 2 + 2n PC
Status Affected: None
Encoding: 1110 0011 nnnn nnnn
Description: If the Carry bit is ‘0’, then the program
will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
No
operation
Example: HERE BNC Jump
Before Instruction
PC = address (HERE)
After Instruction
If Carry = 0;
PC = address (Jump)
If Carry = 1;
PC = address (HERE + 2)
BNN Branch if Not Negative
Syntax: BNN n
Operands: -128 n 127
Operation: if Negative bit is ‘0’,
(PC) + 2 + 2n PC
Status Affected: None
Encoding: 1110 0111 nnnn nnnn
Description: If the Negative bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
No
operation
Example: HERE BNN Jump
Before Instruction
PC = address (HERE)
After Instruction
If Negative = 0;
PC = address (Jump)
If Negative = 1;
PC = address (HERE + 2)
PIC18F97J94 FAMILY
DS30575A-page 586 2012 Microchip Technology Inc.
BNOV Branch if Not Overflow
Syntax: BNOV n
Operands: -128 n 127
Operation: if Overflow bit is ‘0’,
(PC) + 2 + 2n PC
Status Affected: None
Encoding: 1110 0101 nnnn nnnn
Description: If the Overflow bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
No
operation
Example: HERE BNOV Jump
Before Instruction
PC = address (HERE)
After Instruction
If Overflow = 0;
PC = address (Jump)
If Overflow = 1;
PC = address (HERE + 2)
BNZ Branch if Not Zero
Syntax: BNZ n
Operands: -128 n 127
Operation: if Zero bit is ‘0’,
(PC) + 2 + 2n PC
Status Affected: None
Encoding: 1110 0001 nnnn nnnn
Description: If the Zero bit is ‘0’, then the program
will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
No
operation
Example: HERE BNZ Jump
Before Instruction
PC = address (HERE)
After Instruction
If Zero = 0;
PC = address (Jump)
If Zero = 1;
PC = address (HERE + 2)
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BRA Unconditional Branch
Syntax: BRA n
Operands: -1024 n 1023
Operation: (PC) + 2 + 2n PC
Status Affected: None
Encoding: 1101 0nnn nnnn nnnn
Description: Add the 2’s complement number ‘2n’ to
the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is a
two-cycle instruction.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
Example: HERE BRA Jump
Before Instruction
PC = address (HERE)
After Instruction
PC = address (Jump)
BSF Bit Set f
Syntax: BSF f, b {,a}
Operands: 0 f 255
0 b 7
a [0,1]
Operation: 1 f<b>
Status Affected: None
Encoding: 1000 bbba ffff ffff
Description: Bit ‘b’ in register ‘f’ is set.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
register ‘f’
Example: BSF FLAG_REG, 7, 1
Before Instruction
FLAG_REG = 0Ah
After Instruction
FLAG_REG = 8Ah
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BTFSC Bit Test File, Skip if Clear
Syntax: BTFSC f, b {,a}
Operands: 0 f 255
0 b 7
a [0,1]
Operation: skip if (f<b>) = 0
Status Affected: None
Encoding: 1011 bbba ffff ffff
Description: If bit ‘b’ in register ‘f’ is ‘0’, then the next
instruction is skipped. If bit ‘b’ is ‘0’, then
the next instruction fetched during the
current instruction execution is discarded
and a NOP is executed instead, making
this a two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If
‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction set
is enabled, this instruction operates in
Indexed Literal Offset Addressing mode
whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE
FALSE
TRUE
BTFSC
:
:
FLAG, 1, 0
Before Instruction
PC = address (HERE)
After Instruction
If FLAG<1> = 0;
PC = address (TRUE)
If FLAG<1> = 1;
PC = address (FALSE)
BTFSS Bit Test File, Skip if Set
Syntax: BTFSS f, b {,a}
Operands: 0 f 255
0 b < 7
a [0,1]
Operation: skip if (f<b>) = 1
Status Affected: None
Encoding: 1010 bbba ffff ffff
Description: If bit ‘b’ in register ‘f’ is ‘1’, then the next
instruction is skipped. If bit ‘b’ is ‘1’, then
the next instruction fetched during the
current instruction execution is discarded
and a NOP is executed instead, making
this a two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected. If
‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode
whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE
FALSE
TRUE
BTFSS
:
:
FLAG, 1, 0
Before Instruction
PC = address (HERE)
After Instruction
If FLAG<1> = 0;
PC = address (FALSE)
If FLAG<1> = 1;
PC = address (TRUE)
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BTG Bit Toggle f
Syntax: BTG f, b {,a}
Operands: 0 f 255
0 b < 7
a [0,1]
Operation: (f<b>) f<b>
Status Affected: None
Encoding: 0111 bbba ffff ffff
Description: Bit ‘b’ in data memory location, ‘f’, is
inverted.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
register ‘f’
Example: BTG PORTC, 4, 0
Before Instruction:
PORTC = 0111 0101 [75h]
After Instruction:
PORTC = 0110 0101 [65h]
BOV Branch if Overflow
Syntax: BOV n
Operands: -128 n 127
Operation: if Overflow bit is ‘1’,
(PC) + 2 + 2n PC
Status Affected: None
Encoding: 1110 0100 nnnn nnnn
Description: If the Overflow bit is ‘1’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
No
operation
Example: HERE BOV Jump
Before Instruction
PC = address (HERE)
After Instruction
If Overflow = 1;
PC = address (Jump)
If Overflow = 0;
PC = address (HERE + 2)
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BZ Branch if Zero
Syntax: BZ n
Operands: -128 n 127
Operation: if Zero bit is ‘1’,
(PC) + 2 + 2n PC
Status Affected: None
Encoding: 1110 0000 nnnn nnnn
Description: If the Zero bit is ‘1’, then the program
will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
If Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
Process
Data
No
operation
Example: HERE BZ Jump
Before Instruction
PC = address (HERE)
After Instruction
If Zero = 1;
PC = address (Jump)
If Zero = 0;
PC = address (HERE + 2)
CALL Subroutine Call
Syntax: CALL k {,s}
Operands: 0 k 1048575
s [0,1]
Operation: (PC) + 4 TOS,
k PC<20:1>;
if s = 1
(W) WS,
(STATUS) STATUSS,
(BSR) BSRS
Status Affected: None
Encoding:
1st word (k<7:0>)
2nd word(k<19:8>)
1110
1111
110s
k19kkk
k7kkk
kkkk
kkkk0
kkkk8
Description: Subroutine call of entire 2-Mbyte
memory range. First, return address
(PC+ 4) is pushed onto the return stack.
If ‘s’ = 1, the W, STATUS and BSR
registers are also pushed into their
respective shadow registers, WS,
STATUSS and BSRS. If ‘s’ = 0, no
update occurs. Then, the 20-bit value ‘k’
is loaded into PC<20:1>. CALL is a
two-cycle instruction.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
‘k’<7:0>,
Push PC to
stack
Read literal
’k’<19:8>,
Write to PC
No
operation
No
operation
No
operation
No
operation
Example: HERE CALL THERE,1
Before Instruction
PC = address (HERE)
After Instruction
PC = address (THERE)
TOS = address (HERE + 4)
WS = W
BSRS = BSR
STATUSS = STATUS
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CLRF Clear f
Syntax: CLRF f {,a}
Operands: 0 f 255
a [0,1]
Operation: 000h f,
1 Z
Status Affected: Z
Encoding: 0110 101a ffff ffff
Description: Clears the contents of the specified
register.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
register ‘f’
Example: CLRF FLAG_REG,1
Before Instruction
FLAG_REG = 5Ah
After Instruction
FLAG_REG = 00h
CLRWDT Clear Watchdog Timer
Syntax: CLRWDT
Operands: None
Operation: 000h WDT,
000h WDT postscaler,
1 TO,
1 PD
Status Affected: TO, PD
Encoding: 0000 0000 0000 0100
Description: CLRWDT instruction resets the
Watchdog Timer. It also resets the post-
scaler of the WDT. Status bits, TO and
PD, are set.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Process
Data
No
operation
Example: CLRWDT
Before Instruction
WDT Counter = ?
After Instruction
WDT Counter = 00h
WDT Postscaler = 0
TO =1
PD =1
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COMF Complement f
Syntax: COMF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: f dest
Status Affected: N, Z
Encoding: 0001 11da ffff ffff
Description: The contents of register ‘f’ are
complemented. If ‘d’ is ‘0’, the result is
stored in W. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: COMF REG, 0, 0
Before Instruction
REG = 13h
After Instruction
REG = 13h
W=ECh
CPFSEQ Compare f with W, Skip if f = W
Syntax: CPFSEQ f {,a}
Operands: 0 f 255
a [0,1]
Operation: (f) – (W),
skip if (f) = (W)
(unsigned comparison)
Status Affected: None
Encoding: 0110 001a ffff ffff
Description: Compares the contents of data memory
location ‘f’ to the contents of W by
performing an unsigned subtraction.
If ‘f’ = W, then the fetched instruction is
discarded and a NOP is executed
instead, making this a two-cycle
instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CPFSEQ REG, 0
NEQUAL :
EQUAL :
Before Instruction
PC Address = HERE
W=?
REG = ?
After Instruction
If REG = W;
PC = Address (EQUAL)
If REG W;
PC = Address (NEQUAL)
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CPFSGT Compare f with W, Skip if f > W
Syntax: CPFSGT f {,a}
Operands: 0 f 255
a [0,1]
Operation: (f) –W),
skip if (f) > (W)
(unsigned comparison)
Status Affected: None
Encoding: 0110 010a ffff ffff
Description: Compares the contents of data memory
location ‘f’ to the contents of the W by
performing an unsigned subtraction.
If the contents of ‘f’ are greater than the
contents of WREG, then the fetched
instruction is discarded and a NOP is
executed instead, making this a
two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CPFSGT REG, 0
NGREATER :
GREATER :
Before Instruction
PC = Address (HERE)
W= ?
After Instruction
If REG W;
PC = Address (GREATER)
If REG W;
PC = Address (NGREATER)
CPFSLT Compare f with W, Skip if f < W
Syntax: CPFSLT f {,a}
Operands: 0 f 255
a [0,1]
Operation: (f) –W),
skip if (f) < (W)
(unsigned comparison)
Status Affected: None
Encoding: 0110 000a ffff ffff
Description: Compares the contents of data memory
location ‘f’ to the contents of W by
performing an unsigned subtraction.
If the contents of ‘f’ are less than the
contents of W, then the fetched
instruction is discarded and a NOP is
executed instead, making this a
two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CPFSLT REG, 1
NLESS :
LESS :
Before Instruction
PC = Address (HERE)
W= ?
After Instruction
If REG < W;
PC = Address (LESS)
If REG W;
PC = Address (NLESS)
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DAW Decimal Adjust W Register
Syntax: DAW
Operands: None
Operation: If [W<3:0> > 9] or [DC = 1], then
(W<3:0>) + 6 W<3:0>;
else
(W<3:0>) W<3:0>
If [W<7:4> > 9] or [C = 1], then
(W<7:4>) + 6 W<7:4>;
C =1;
else
(W<7:4>) W<7:4>
Status Affected: C
Encoding: 0000 0000 0000 0111
Description: DAW adjusts the 8-bit value in W,
resulting from the earlier addition of two
variables (each in packed BCD format)
and produces a correct packed BCD
result.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register W
Process
Data
Write
W
Example 1: DAW
Before Instruction
W=A5h
C=0
DC = 0
After Instruction
W = 05h
C=1
DC = 0
Example 2:
Before Instruction
W=CEh
C=0
DC = 0
After Instruction
W = 34h
C=1
DC = 0
DECF Decrement f
Syntax: DECF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f) – 1 dest
Status Affected: C, DC, N, OV, Z
Encoding: 0000 01da ffff ffff
Description: Decrement register, ‘f’. If ‘d’ is ‘0’, the
result is stored in W. If ‘d’ is ‘1’, the
result is stored back in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: DECF CNT, 1, 0
Before Instruction
CNT = 01h
Z=0
After Instruction
CNT = 00h
Z=1
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DECFSZ Decrement f, Skip if 0
Syntax: DECFSZ f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f) – 1 dest,
skip if result = 0
Status Affected: None
Encoding: 0010 11da ffff ffff
Description: The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
If the result is ‘0’, the next instruction
which is already fetched is discarded
and a NOP is executed instead, making
it a two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE DECFSZ CNT, 1, 1
GOTO LOOP
CONTINUE
Before Instruction
PC = Address (HERE)
After Instruction
CNT = CNT – 1
If CNT = 0;
PC = Address (CONTINUE)
If CNT 0;
PC = Address (HERE + 2)
DCFSNZ Decrement f, Skip if Not 0
Syntax: DCFSNZ f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f) – 1 dest,
skip if result 0
Status Affected: None
Encoding: 0100 11da ffff ffff
Description: The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
If the result is not ‘0’, the next
instruction which is already fetched is
discarded and a NOP is executed
instead, making it a two-cycle
instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE DCFSNZ TEMP, 1, 0
ZERO :
NZERO :
Before Instruction
TEMP = ?
After Instruction
TEMP = TEMP – 1,
If TEMP = 0;
PC = Address (ZERO)
If TEMP 0;
PC = Address (NZERO)
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GOTO Unconditional Branch
Syntax: GOTO k
Operands: 0 k 1048575
Operation: k PC<20:1>
Status Affected: None
Encoding:
1st word (k<7:0>)
2nd word(k<19:8>)
1110
1111
1111
k19kkk
k7kkk
kkkk
kkkk0
kkkk8
Description: GOTO allows an unconditional branch
anywhere within entire 2-Mbyte memory
range. The 20-bit value ‘k’ is loaded into
PC<20:1>. GOTO is always a two-cycle
instruction.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
‘k’<7:0>,
No
operation
Read literal
‘k’<19:8>,
Write to PC
No
operation
No
operation
No
operation
No
operation
Example: GOTO THERE
After Instruction
PC = Address (THERE)
INCF Increment f
Syntax: INCF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f) + 1 dest
Status Affected: C, DC, N, OV, Z
Encoding: 0010 10da ffff ffff
Description: The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: INCF CNT, 1, 0
Before Instruction
CNT = FFh
Z=0
C=?
DC = ?
After Instruction
CNT = 00h
Z=1
C=1
DC = 1
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INCFSZ Increment f, Skip if 0
Syntax: INCFSZ f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f) + 1 dest,
skip if result = 0
Status Affected: None
Encoding: 0011 11da ffff ffff
Description: The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
If the result is ‘0’, the next instruction
which is already fetched is discarded
and a NOP is executed instead, making
it a two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE INCFSZ CNT, 1, 0
NZERO :
ZERO :
Before Instruction
PC = Address (HERE)
After Instruction
CNT = CNT + 1
If CNT = 0;
PC = Address (ZERO)
If CNT 0;
PC = Address (NZERO)
INFSNZ Increment f, Skip if Not 0
Syntax: INFSNZ f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f) + 1 dest,
skip if result 0
Status Affected: None
Encoding: 0100 10da ffff ffff
Description: The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
If the result is not ‘0’, the next
instruction which is already fetched is
discarded and a NOP is executed
instead, making it a two-cycle
instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE INFSNZ REG, 1, 0
ZERO
NZERO
Before Instruction
PC = Address (HERE)
After Instruction
REG = REG + 1
If REG 0;
PC = Address (NZERO)
If REG = 0;
PC = Address (ZERO)
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IORLW Inclusive OR Literal with W
Syntax: IORLW k
Operands: 0 k 255
Operation: (W) .OR. k W
Status Affected: N, Z
Encoding: 0000 1001 kkkk kkkk
Description: The contents of W are ORed with the
eight-bit literal ‘k’. The result is placed
in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
Write to
W
Example: IORLW 35h
Before Instruction
W=9Ah
After Instruction
W=BFh
IORWF Inclusive OR W with f
Syntax: IORWF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (W) .OR. (f) dest
Status Affected: N, Z
Encoding: 0001 00da ffff ffff
Description: Inclusive OR W with register ‘f’. If ‘d’ is
‘0’, the result is placed in W. If ‘d’ is ‘1’,
the result is placed back in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: IORWF RESULT, 0, 1
Before Instruction
RESULT = 13h
W = 91h
After Instruction
RESULT = 13h
W = 93h
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LFSR Load FSR
Syntax: LFSR f, k
Operands: 0 f 2
0 k 4095
Operation: k FSRf
Status Affected: None
Encoding: 1110
1111
1110
0000
00ff
k7kkk
k11kkk
kkkk
Description: The 12-bit literal ‘k’ is loaded into the
file select register pointed to by ‘f’.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
‘k’ MSB
Process
Data
Write
literal ‘k’
MSB to
FSRfH
Decode Read literal
‘k’ LSB
Process
Data
Write literal
‘k’ to FSRfL
Example: LFSR 2, 3ABh
After Instruction
FSR2H = 03h
FSR2L = ABh
MOVF Move f
Syntax: MOVF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: f dest
Status Affected: N, Z
Encoding: 0101 00da ffff ffff
Description: The contents of register ‘f’ are moved to
a destination dependent upon the
status of ‘d’. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’. Location ‘f’
can be anywhere in the
256-byte bank.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
W
Example: MOVF REG, 0, 0
Before Instruction
REG = 22h
W=FFh
After Instruction
REG = 22h
W = 22h
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MOVFF Move f to f
Syntax: MOVFF fs,fd
Operands: 0 fs 4095
0 fd 4095
Operation: (fs) fd
Status Affected: None
Encoding:
1st word (source)
2nd word (destin.)
1100
1111
ffff
ffff
ffff
ffff
ffffs
ffffd
Description: The contents of source register, ‘fs’, are
moved to destination register ‘fd’.
Location of source ‘fs’ can be anywhere
in the 4096-byte data space (000h to
FFFh) and location of destination ‘fd’
can also be anywhere from 000h to
FFFh.
Either source or destination can be W
(a useful special situation).
MOVFF is particularly useful for
transferring a data memory location to a
peripheral register (such as the transmit
buffer or an I/O port).
The MOVFF instruction cannot use the
PCL, TOSU, TOSH or TOSL as the
destination register
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
(src)
Process
Data
No
operation
Decode No
operation
No dummy
read
No
operation
Write
register ‘f’
(dest)
Example: MOVFF REG1, REG2
Before Instruction
REG1 = 33h
REG2 = 11h
After Instruction
REG1 = 33h
REG2 = 33h
MOVLB Move Literal to Low Nibble in BSR
Syntax: MOVLB k
Operands: 0 k 255
Operation: k BSR
Status Affected: None
Encoding: 0000 0001 kkkk kkkk
Description: The eight-bit literal ‘k’ is loaded into the
Bank Select Register (BSR). The value
of BSR<7:4> always remains ‘0’
regardless of the value of k7:k4.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
Write literal
‘k’ to BSR
Example: MOVLB 5
Before Instruction
BSR Register = 02h
After Instruction
BSR Register = 05h
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MOVLW Move Literal to W
Syntax: MOVLW k
Operands: 0 k 255
Operation: k W
Status Affected: None
Encoding: 0000 1110 kkkk kkkk
Description: The eight-bit literal ‘k’ is loaded into W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
Write to
W
Example: MOVLW 5Ah
After Instruction
W=5Ah
MOVWF Move W to f
Syntax: MOVWF f {,a}
Operands: 0 f 255
a [0,1]
Operation: (W) f
Status Affected: None
Encoding: 0110 111a ffff ffff
Description: Move data from W to register ‘f’.
Location ‘f’ can be anywhere in the
256-byte bank.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
register ‘f’
Example: MOVWF REG, 0
Before Instruction
W=4Fh
REG = FFh
After Instruction
W=4Fh
REG = 4Fh
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MULLW Multiply Literal with W
Syntax: MULLW k
Operands: 0 k 255
Operation: (W) x k PRODH:PRODL
Status Affected: None
Encoding: 0000 1101 kkkk kkkk
Description: An unsigned multiplication is carried
out between the contents of W and the
8-bit literal ‘k’. The 16-bit result is
placed in the PRODH:PRODL register
pair. PRODH contains the high byte.
W is unchanged.
None of the Status flags are affected.
Note that neither Overflow nor Carry is
possible in this operation. A Zero result
is possible but not detected.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
Write
registers
PRODH:
PRODL
Example: MULLW 0C4h
Before Instruction
W=E2h
PRODH = ?
PRODL = ?
After Instruction
W=E2h
PRODH = ADh
PRODL = 08h
MULWF Multiply W with f
Syntax: MULWF f {,a}
Operands: 0 f 255
a [0,1]
Operation: (W) x (f) PRODH:PRODL
Status Affected: None
Encoding: 0000 001a ffff ffff
Description: An unsigned multiplication is carried out
between the contents of W and the
register file location ‘f’. The 16-bit result is
stored in the PRODH:PRODL register
pair. PRODH contains the high byte. Both
W and ‘f’ are unchanged.
None of the Status flags are affected.
Note that neither Overflow nor Carry is
possible in this operation. A Zero result is
possible but not detected.
If ‘a’ is ‘0’, the Access Bank is selected. If
‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction set
is enabled, this instruction operates in
Indexed Literal Offset Addressing mode
whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
registers
PRODH:
PRODL
Example: MULWF REG, 1
Before Instruction
W=C4h
REG = B5h
PRODH = ?
PRODL = ?
After Instruction
W=C4h
REG = B5h
PRODH = 8Ah
PRODL = 94h
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NEGF Negate f
Syntax: NEGF f {,a}
Operands: 0 f 255
a [0,1]
Operation: (f) + 1 f
Status Affected: N, OV, C, DC, Z
Encoding: 0110 110a ffff ffff
Description: Location ‘f’ is negated using two’s
complement. The result is placed in the
data memory location ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
register ‘f’
Example: NEGF REG, 1
Before Instruction
REG = 0011 1010 [3Ah]
After Instruction
REG = 1100 0110 [C6h]
NOP No Operation
Syntax: NOP
Operands: None
Operation: No operation
Status Affected: None
Encoding: 0000
1111
0000
xxxx
0000
xxxx
0000
xxxx
Description: No operation.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
No
operation
Example:
None.
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POP Pop Top of Return Stack
Syntax: POP
Operands: None
Operation: (TOS) bit bucket
Status Affected: None
Encoding: 0000 0000 0000 0110
Description: The TOS value is pulled off the return
stack and is discarded. The TOS value
then becomes the previous value that
was pushed onto the return stack.
This instruction is provided to enable
the user to properly manage the return
stack to incorporate a software stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
POP TOS
value
No
operation
Example: POP
GOTO NEW
Before Instruction
TOS = 0031A2h
Stack (1 level down) = 014332h
After Instruction
TOS = 014332h
PC = NEW
PUSH Push Top of Return Stack
Syntax: PUSH
Operands: None
Operation: (PC + 2) TOS
Status Affected: None
Encoding: 0000 0000 0000 0101
Description: The PC + 2 is pushed onto the top of
the return stack. The previous TOS
value is pushed down on the stack.
This instruction allows implementing a
software stack by modifying TOS and
then pushing it onto the return stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode PUSH
PC + 2 onto
return stack
No
operation
No
operation
Example: PUSH
Before Instruction
TOS = 345Ah
PC = 0124h
After Instruction
PC = 0126h
TOS = 0126h
Stack (1 level down) = 345Ah
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RCALL Relative Call
Syntax: RCALL n
Operands: -1024 n 1023
Operation: (PC) + 2 TOS,
(PC) + 2 + 2n PC
Status Affected: None
Encoding: 1101 1nnn nnnn nnnn
Description: Subroutine call with a jump up to 1K
from the current location. First, return
address (PC + 2) is pushed onto the
stack. Then, add the 2’s complement
number ‘2n’ to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is a
two-cycle instruction.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read literal
‘n’
PUSH PC
to stack
Process
Data
Write to PC
No
operation
No
operation
No
operation
No
operation
Example: HERE RCALL Jump
Before Instruction
PC = Address (HERE)
After Instruction
PC = Address (Jump)
TOS = Address (HERE + 2)
RESET Reset
Syntax: RESET
Operands: None
Operation: Reset all registers and flags that are
affected by a MCLR Reset.
Status Affected: All
Encoding: 0000 0000 1111 1111
Description: This instruction provides a way to
execute a MCLR Reset in software.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Start
reset
No
operation
No
operation
Example: RESET
After Instruction
Registers = Reset Value
Flags* = Reset Value
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RETFIE Return from Interrupt
Syntax: RETFIE {s}
Operands: s [0,1]
Operation: (TOS) PC,
1 GIE/GIEH or PEIE/GIEL;
if s = 1,
(WS) W,
(STATUSS) STATUS,
(BSRS) BSR,
PCLATU, PCLATH are unchanged
Status Affected: GIE/GIEH, PEIE/GIEL.
Encoding: 0000 0000 0001 000s
Description: Return from interrupt. Stack is popped
and Top-of-Stack (TOS) is loaded into
the PC. Interrupts are enabled by
setting either the high or low-priority
Global Interrupt Enable bit. If ‘s’ = 1, the
contents of the shadow registers WS,
STATUSS and BSRS are loaded into
their corresponding registers W,
STATUS and BSR. If ‘s’ = 0, no update
of these registers occurs.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
POP PC
from stack
Set GIEH or
GIEL
No
operation
No
operation
No
operation
No
operation
Example: RETFIE 1
After Interrupt
PC = TOS
W=WS
BSR = BSRS
STATUS = STATUSS
GIE/GIEH, PEIE/GIEL = 1
RETLW Return Literal to W
Syntax: RETLW k
Operands: 0 k 255
Operation: k W,
(TOS) PC,
PCLATU, PCLATH are unchanged
Status Affected: None
Encoding: 0000 1100 kkkk kkkk
Description: W is loaded with the 8-bit literal ‘k’. The
Program Counter is loaded from the top
of the stack (the return address). The
high address latch (PCLATH) remains
unchanged.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
POP PC
from stack,
write to W
No
operation
No
operation
No
operation
No
operation
Example:
CALL TABLE ; W contains table
; offset value
; W now has
; table value
:
TABLE
ADDWF PCL ; W = offset
RETLW k0 ; Begin table
RETLW k1 ;
:
:
RETLW kn ; End of table
Before Instruction
W = 07h
After Instruction
W = value of kn
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RETURN Return from Subroutine
Syntax: RETURN {s}
Operands: s [0,1]
Operation: (TOS) PC;
if s = 1,
(WS) W,
(STATUSS) STATUS,
(BSRS) BSR,
PCLATU, PCLATH are unchanged
Status Affected: None
Encoding: 0000 0000 0001 001s
Description: Return from subroutine. The stack is
popped and the top of the stack (TOS)
is loaded into the Program Counter. If
‘s’= 1, the contents of the shadow
registers WS, STATUSS and BSRS are
loaded into their corresponding
registers W, STATUS and BSR. If
‘s’ = 0, no update of these registers
occurs.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Process
Data
POP PC
from stack
No
operation
No
operation
No
operation
No
operation
Example: RETURN
After Instruction:
PC = TOS
RLCF Rotate Left f through Carry
Syntax: RLCF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f<n>) dest<n + 1>,
(f<7>) C,
(C) dest<0>
Status Affected: C, N, Z
Encoding: 0011 01da ffff ffff
Description: The contents of register ‘f’ are rotated
one bit to the left through the Carry flag.
If ‘d’ is ‘0’, the result is placed in W. If ‘d’
is ‘1’, the result is stored back in register
‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: RLCF REG, 0, 0
Before Instruction
REG = 1110 0110
C=0
After Instruction
REG = 1110 0110
W=1100 1100
C=1
Cregister f
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RLNCF Rotate Left f (No Carry)
Syntax: RLNCF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f<n>) dest<n + 1>,
(f<7>) dest<0>
Status Affected: N, Z
Encoding: 0100 01da ffff ffff
Description: The contents of register ‘f’ are rotated
one bit to the left. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: RLNCF REG, 1, 0
Before Instruction
REG = 1010 1011
After Instruction
REG = 0101 0111
register f
RRCF Rotate Right f through Carry
Syntax: RRCF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f<n>) dest<n – 1>,
(f<0>) C,
(C) dest<7>
Status Affected: C, N, Z
Encoding: 0011 00da ffff ffff
Description: The contents of register ‘f’ are rotated
one bit to the right through the Carry
flag. If ‘d’ is ‘0’, the result is placed in W.
If ‘d’ is ‘1’, the result is placed back in
register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: RRCF REG, 0, 0
Before Instruction
REG = 1110 0110
C=0
After Instruction
REG = 1110 0110
W=0111 0011
C=0
Cregister f
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RRNCF Rotate Right f (No Carry)
Syntax: RRNCF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f<n>) dest<n – 1>,
(f<0>) dest<7>
Status Affected: N, Z
Encoding: 0100 00da ffff ffff
Description: The contents of register ‘f’ are rotated
one bit to the right. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
If ‘a’ is ‘0’, the Access Bank will be
selected, overriding the BSR value. If ‘a’
is ‘1’, then the bank will be selected as
per the BSR value.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example 1: RRNCF REG, 1, 0
Before Instruction
REG = 1101 0111
After Instruction
REG = 1110 1011
Example 2: RRNCF REG, 0, 0
Before Instruction
W=?
REG = 1101 0111
After Instruction
W=1110 1011
REG = 1101 0111
register f
SETF Set f
Syntax: SETF f {,a}
Operands: 0 f 255
a [0,1]
Operation: FFh f
Status Affected: None
Encoding: 0110 100a ffff ffff
Description: The contents of the specified register
are set to FFh.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
register ‘f’
Example: SETF REG,1
Before Instruction
REG = 5Ah
After Instruction
REG = FFh
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SLEEP Enter Sleep Mode
Syntax: SLEEP
Operands: None
Operation: 00h WDT,
0 WDT postscaler,
1 TO,
0 PD
Status Affected: TO, PD
Encoding: 0000 0000 0000 0011
Description: The Power-Down status bit (PD) is
cleared. The Time-out status bit (TO)
is set. The Watchdog Timer and its
postscaler are cleared.
The processor is put into Sleep mode
with the oscillator stopped.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Process
Data
Go to
Sleep
Example: SLEEP
Before Instruction
TO =?
PD =?
After Instruction
TO =1 †
PD =0
† If WDT causes wake-up, this bit is cleared.
SUBFWB Subtract f from W with Borrow
Syntax: SUBFWB f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (W) – (f) – (C) dest
Status Affected: N, OV, C, DC, Z
Encoding: 0101 01da ffff ffff
Description: Subtract register ‘f’ and Carry flag
(borrow) from W (2’s complement
method). If ‘d’ is ‘0’, the result is stored in
W. If ‘d’ is ‘1’, the result is stored in
register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected. If
‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode
whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example 1: SUBFWB REG, 1, 0
Before Instruction
REG = 3
W=2
C=1
After Instruction
REG = FF
W=2
C=0
Z=0
N = 1 ; result is negative
Example 2: SUBFWB REG, 0, 0
Before Instruction
REG = 2
W=5
C=1
After Instruction
REG = 2
W=3
C=1
Z=0
N = 0 ; result is positive
Example 3: SUBFWB REG, 1, 0
Before Instruction
REG = 1
W=2
C=0
After Instruction
REG = 0
W=2
C=1
Z = 1 ; result is zero
N=0
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SUBLW Subtract W from Literal
Syntax: SUBLW k
Operands: 0 k 255
Operation: k – (W) W
Status Affected: N, OV, C, DC, Z
Encoding: 0000 1000 kkkk kkkk
Description: W is subtracted from the eight-bit
literal ‘k’. The result is placed in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
Write to
W
Example 1: SUBLW 02h
Before Instruction
W = 01h
C=?
After Instruction
W = 01h
C=1 ; result is positive
Z=0
N=0
Example 2: SUBLW 02h
Before Instruction
W = 02h
C=?
After Instruction
W = 00h
C=1 ; result is zero
Z=1
N=0
Example 3: SUBLW 02h
Before Instruction
W = 03h
C=?
After Instruction
W = FFh ; (2’s complement)
C=0 ; result is negative
Z=0
N=1
SUBWF Subtract W from f
Syntax: SUBWF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f) – (W) dest
Status Affected: N, OV, C, DC, Z
Encoding: 0101 11da ffff ffff
Description: Subtract W from register ‘f’ (2’s
complement method). If ‘d’ is ‘0’, the
result is stored in W. If ‘d’ is ‘1’, the result
is stored back in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example 1: SUBWF REG, 1, 0
Before Instruction
REG = 3
W=2
C=?
After Instruction
REG = 1
W=2
C = 1 ; result is positive
Z=0
N=0
Example 2: SUBWF REG, 0, 0
Before Instruction
REG = 2
W=2
C=?
After Instruction
REG = 2
W=0
C = 1 ; result is zero
Z=1
N=0
Example 3: SUBWF REG, 1, 0
Before Instruction
REG = 1
W=2
C=?
After Instruction
REG = FFh ;(2’s complement)
W=2
C = 0 ; result is negative
Z=0
N=1
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SUBWFB Subtract W from f with Borrow
Syntax: SUBWFB f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f) – (W) – (C) dest
Status Affected: N, OV, C, DC, Z
Encoding: 0101 10da ffff ffff
Description: Subtract W and the Carry flag (borrow)
from register ‘f’ (2’s complement
method). If ‘d’ is ‘0’, the result is stored
in W. If ‘d’ is ‘1’, the result is stored back
in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example 1: SUBWFB REG, 1, 0
Before Instruction
REG = 19h (0001 1001)
W=0Dh(0000 1101)
C=1
After Instruction
REG = 0Ch (0000 1011)
W=0Dh(0000 1101)
C=1
Z=0
N=0 ; result is positive
Example 2: SUBWFB REG, 0, 0
Before Instruction
REG = 1Bh (0001 1011)
W=1Ah(0001 1010)
C=0
After Instruction
REG = 1Bh (0001 1011)
W = 00h
C=1
Z=1 ; result is zero
N=0
Example 3: SUBWFB REG, 1, 0
Before Instruction
REG = 03h (0000 0011)
W=0Eh(0000 1101)
C=1
After Instruction
REG = F5h (1111 0100)
; [2’s comp]
W=0Eh(0000 1101)
C=0
Z=0
N=1 ; result is negative
SWAPF Swap f
Syntax: SWAPF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (f<3:0>) dest<7:4>,
(f<7:4>) dest<3:0>
Status Affected: None
Encoding: 0011 10da ffff ffff
Description: The upper and lower nibbles of register
‘f’ are exchanged. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result is
placed in register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: SWAPF REG, 1, 0
Before Instruction
REG = 53h
After Instruction
REG = 35h
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TBLRD Table Read
Syntax: TBLRD ( *; *+; *-; +*)
Operands: None
Operation: if TBLRD *,
(Prog Mem (TBLPTR)) TABLAT;
TBLPTR – No Change
if TBLRD *+,
(Prog Mem (TBLPTR)) TABLAT;
(TBLPTR) + 1 TBLPTR
if TBLRD *-,
(Prog Mem (TBLPTR)) TABLAT;
(TBLPTR) – 1 TBLPTR
if TBLRD +*,
(TBLPTR) + 1 TBLPTR;
(Prog Mem (TBLPTR)) TABLAT
Status Affected: None
Encoding: 0000 0000 0000 10nn
nn=0 *
=1 *+
=2 *-
=3 +*
Description: This instruction is used to read the contents
of Program Memory (P.M.). To address the
program memory, a pointer called Table
Pointer (TBLPTR) is used.
The TBLPTR (a 21-bit pointer) points to
each byte in the program memory. TBLPTR
has a 2-Mbyte address range.
TBLPTR<0> = 0:Least Significant Byte of
Program Memory Word
TBLPTR<0> = 1:Most Significant Byte of
Program Memory Word
The TBLRD instruction can modify the value
of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
No
operation
No
operation
No operation
(Read Program
Memory)
No
operation
No operation
(Write
TABLAT)
TBLRD Table Read (Continued)
Example 1: TBLRD *+ ;
Before Instruction
TABLAT = 55h
TBLPTR = 00A356h
MEMORY(00A356h) = 34h
After Instruction
TABLAT = 34h
TBLPTR = 00A357h
Example 2: TBLRD +* ;
Before Instruction
TABLAT = AAh
TBLPTR = 01A357h
MEMORY(01A357h) = 12h
MEMORY(01A358h) = 34h
After Instruction
TABLAT = 34h
TBLPTR = 01A358h
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TBLWT Table Write
Syntax: TBLWT ( *; *+; *-; +*)
Operands: None
Operation: if TBLWT*,
(TABLAT) Holding Register;
TBLPTR – No Change
if TBLWT*+,
(TABLAT) Holding Register;
(TBLPTR) + 1 TBLPTR
if TBLWT*-,
(TABLAT) Holding Register;
(TBLPTR) – 1 TBLPTR
if TBLWT+*,
(TBLPTR) + 1 TBLPTR;
(TABLAT) Holding Register
Status Affected: None
Encoding: 0000 0000 0000 11nn
nn=0 *
=1 *+
=2 *-
=3 +*
Description: This instruction uses the 3 LSBs of
TBLPTR to determine which of the
8 holding registers the TABLAT is written
to. The holding registers are used to
program the contents of Program Memory
(P.M.). (Refer to Section 6.0 “Memory
Organization” for additional details on
programming Flash memory.)
The TBLPTR (a 21-bit pointer) points to
each byte in the program memory.
TBLPTR has a 2-Mbyte address range.
The LSb of the TBLPTR selects which
byte of the program memory location to
access.
TBLPTR[0] = 0:Least Significant Byte
of Program Memory
Word
TBLPTR[0] = 1:Most Significant Byte of
Program Memory
Word
The TBLWT instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
No
operation
No
operation
No
operation
No
operation
(Read
TABLAT)
No
operation
No
operation
(Write to
Holding
Register)
TBLWT Table Write (Continued)
Example 1: TBLWT *+;
Before Instruction
TABLAT = 55h
TBLPTR = 00A356h
HOLDING REGISTER
(00A356h) = FFh
After Instructions (table write completion)
TABLAT = 55h
TBLPTR = 00A357h
HOLDING REGISTER
(00A356h) = 55h
Example 2: TBLWT +*;
Before Instruction
TABLAT = 34h
TBLPTR = 01389Ah
HOLDING REGISTER
(01389Ah) = FFh
HOLDING REGISTER
(01389Bh) = FFh
After Instruction (table write completion)
TABLAT = 34h
TBLPTR = 01389Bh
HOLDING REGISTER
(01389Ah) = FFh
HOLDING REGISTER
(01389Bh) = 34h
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TSTFSZ Test f, Skip if 0
Syntax: TSTFSZ f {,a}
Operands: 0 f 255
a [0,1]
Operation: skip if f = 0
Status Affected: None
Encoding: 0110 011a ffff ffff
Description: If ‘f’ = 0, the next instruction fetched
during the current instruction execution
is discarded and a NOP is executed,
making this a two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
No
operation
If skip:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1 Q2 Q3 Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE TSTFSZ CNT, 1
NZERO :
ZERO :
Before Instruction
PC = Address (HERE)
After Instruction
If CNT = 00h,
PC = Address (ZERO)
If CNT 00h,
PC = Address (NZERO)
XORLW Exclusive OR Literal with W
Syntax: XORLW k
Operands: 0 k 255
Operation: (W) .XOR. k W
Status Affected: N, Z
Encoding: 0000 1010 kkkk kkkk
Description: The contents of W are XORed with
the 8-bit literal ‘k’. The result is placed
in W.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
Write to
W
Example: XORLW 0AFh
Before Instruction
W=B5h
After Instruction
W=1Ah
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XORWF Exclusive OR W with f
Syntax: XORWF f {,d {,a}}
Operands: 0 f 255
d [0,1]
a [0,1]
Operation: (W) .XOR. (f) dest
Status Affected: N, Z
Encoding: 0001 10da ffff ffff
Description: Exclusive OR the contents of W with
register ‘f’. If ‘d’ is ‘0’, the result is stored
in W. If ‘d’ is ‘1’, the result is stored back
in the register ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f 95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: XORWF REG, 1, 0
Before Instruction
REG = AFh
W=B5h
After Instruction
REG = 1Ah
W=B5h
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29.2 Extended Instruction Set
In addition to the standard 75 instructions of the PIC18
instruction set, the PIC18F97J94 family of devices also
provides an optional extension to the core CPU func-
tionality. The added features include eight additional
instructions that augment Indirect and Indexed
Addressing operations and the implementation of
Indexed Literal Offset Addressing for many of the
standard PIC18 instructions.
The additional features of the extended instruction set
are enabled by default on unprogrammed devices.
Users must properly set or clear the XINST Configura-
tion bit during programming to enable or disable these
features.
The instructions in the extended set can all be
classified as literal operations, which either manipulate
the File Select Registers, or use them for Indexed
Addressing. Two of the instructions, ADDFSR and
SUBFSR, each have an additional special instantiation
for using FSR2. These versions (ADDULNK and
SUBULNK) allow for automatic return after execution.
The extended instructions are specifically implemented
to optimize re-entrant program code (that is, code that
is recursive or that uses a software stack) written in
high-level languages, particularly C. Among other
things, they allow users working in high-level
languages to perform certain operations on data
structures more efficiently. These include:
• Dynamic allocation and deallocation of software
stack space when entering and leaving
subroutines
• Function Pointer invocation
• Software Stack Pointer manipulation
• Manipulation of variables located in a software
stack
A summary of the instructions in the extended instruc-
tion set is provided in Tabl e 29-3 . Detailed descriptions
are provided in Section 29.2.2 “Extended Instruction
Set”. The opcode field descriptions in Tabl e 29-1
(page 576) apply to both the standard and extended
PIC18 instruction sets.
29.2.1 EXTENDED INSTRUCTION SYNTAX
Most of the extended instructions use indexed argu-
ments, using one of the File Select Registers and some
offset to specify a source or destination register. When
an argument for an instruction serves as part of
Indexed Addressing, it is enclosed in square brackets
(“[ ]”). This is done to indicate that the argument is used
as an index or offset. The MPASM™ Assembler will
flag an error if it determines that an index or offset value
is not bracketed.
When the extended instruction set is enabled, brackets
are also used to indicate index arguments in
byte-oriented and bit-oriented instructions. This is in
addition to other changes in their syntax. For more
details, see Section 29.2.3.1 “Extended Instruction
Syntax with Standard PIC18 Commands”.
TABLE 29-3: EXTENSIONS TO THE PIC18 INSTRUCTION SET
Note: The instruction set extension and the
Indexed Literal Offset Addressing mode
were designed for optimizing applications
written in C; the user may likely never use
these instructions directly in assembler.
The syntax for these commands is
provided as a reference for users who
may be reviewing code that has been
generated by a compiler.
Note: In the past, square brackets have been
used to denote optional arguments in the
PIC18 and earlier instruction sets. In this
text and going forward, optional
arguments are denoted by braces (“{ }”).
Mnemonic,
Operands Description Cycles
16-Bit Instruction Word Status
Affected
MSb LSb
ADDFSR
ADDULNK
CALLW
MOVSF
MOVSS
PUSHL
SUBFSR
SUBULNK
f, k
k
zs, fd
zs, zd
k
f, k
k
Add Literal to FSR
Add Literal to FSR2 and Return
Call Subroutine using WREG
Move zs (source) to 1st word
fd (destination) 2nd word
Move zs (source) to 1st word
zd (destination) 2nd word
Store Literal at FSR2,
Decrement FSR2
Subtract Literal from FSR
Subtract Literal from FSR2 and
return
1
2
2
2
2
1
1
2
1110
1110
0000
1110
1111
1110
1111
1110
1110
1110
1000
1000
0000
1011
ffff
1011
xxxx
1010
1001
1001
ffkk
11kk
0001
0zzz
ffff
1zzz
xzzz
kkkk
ffkk
11kk
kkkk
kkkk
0100
zzzz
ffff
zzzz
zzzz
kkkk
kkkk
kkkk
None
None
None
None
None
None
None
None
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29.2.2 EXTENDED INSTRUCTION SET
ADDFSR Add Literal to FSR
Syntax: ADDFSR f, k
Operands: 0 k 63
f [ 0, 1, 2 ]
Operation: FSR(f) + k FSR(f)
Status Affected: None
Encoding: 1110 1000 ffkk kkkk
Description: The 6-bit literal ‘k’ is added to the
contents of the FSR specified by ‘f’.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
Write to
FSR
Example: ADDFSR 2, 23h
Before Instruction
FSR2 = 03FFh
After Instruction
FSR2 = 0422h
ADDULNK Add Literal to FSR2 and Return
Syntax: ADDULNK k
Operands: 0 k 63
Operation: FSR2 + k FSR2,
(TOS) PC
Status Affected: None
Encoding: 1110 1000 11kk kkkk
Description: The 6-bit literal ‘k’ is added to the
contents of FSR2. A RETURN is then
executed by loading the PC with the
TOS.
The instruction takes two cycles to
execute; a NOP is performed during
the second cycle.
This may be thought of as a special
case of the ADDFSR instruction,
where f = 3 (binary ‘11’); it operates
only on FSR2.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal ‘k’
Process
Data
Write to
FSR
No
Operation
No
Operation
No
Operation
No
Operation
Example: ADDULNK 23h
Before Instruction
FSR2 = 03FFh
PC = 0100h
After Instruction
FSR2 = 0422h
PC = (TOS)
Note: All PIC18 instructions may take an optional label argument preceding the instruction mnemonic for use in
symbolic addressing. If a label is used, the instruction format then becomes: {label} instruction argument(s).
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CALLW Subroutine Call Using WREG
Syntax: CALLW
Operands: None
Operation: (PC + 2) TOS,
(W) PCL,
(PCLATH) PCH,
(PCLATU) PCU
Status Affected: None
Encoding: 0000 0000 0001 0100
Description First, the return address (PC + 2) is
pushed onto the return stack. Next, the
contents of W are written to PCL; the
existing value is discarded. Then, the
contents of PCLATH and PCLATU are
latched into PCH and PCU,
respectively. The second cycle is
executed as a NOP instruction while the
new next instruction is fetched.
Unlike CALL, there is no option to
update W, STATUS or BSR.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
WREG
Push PC to
stack
No
operation
No
operation
No
operation
No
operation
No
operation
Example: HERE CALLW
Before Instruction
PC = address (HERE)
PCLATH = 10h
PCLATU = 00h
W = 06h
After Instruction
PC = 001006h
TOS = address (HERE + 2)
PCLATH = 10h
PCLATU = 00h
W = 06h
MOVSF Move Indexed to f
Syntax: MOVSF [zs], fd
Operands: 0 zs 127
0 fd 4095
Operation: ((FSR2) + zs) fd
Status Affected: None
Encoding:
1st word (source)
2nd word (destin.)
1110
1111
1011
ffff
0zzz
ffff
zzzzs
ffffd
Description: The contents of the source register are
moved to destination register ‘fd’. The
actual address of the source register is
determined by adding the 7-bit literal
offset ‘zs’, in the first word, to the value
of FSR2. The address of the destination
register is specified by the 12-bit literal
‘fd’ in the second word. Both addresses
can be anywhere in the 4096-byte data
space (000h to FFFh).
The MOVSF instruction cannot use the
PCL, TOSU, TOSH or TOSL as the
destination register.
If the resultant source address points to
an Indirect Addressing register, the
value returned will be 00h.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Determine
source addr
Determine
source addr
Read
source reg
Decode No
operation
No dummy
read
No
operation
Write
register ‘f’
(dest)
Example: MOVSF [05h], REG2
Before Instruction
FSR2 = 80h
Contents
of 85h = 33h
REG2 = 11h
After Instruction
FSR2 = 80h
Contents
of 85h = 33h
REG2 = 33h
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MOVSS Move Indexed to Indexed
Syntax: MOVSS [zs], [zd]
Operands: 0 zs 127
0 zd 127
Operation: ((FSR2) + zs) ((FSR2) + zd)
Status Affected: None
Encoding:
1st word (source)
2nd word (dest.)
1110
1111
1011
xxxx
1zzz
xzzz
zzzzs
zzzzd
Description The contents of the source register are
moved to the destination register. The
addresses of the source and destination
registers are determined by adding the
7-bit literal offsets, ‘zs’ or ‘zd’,
respectively, to the value of FSR2. Both
registers can be located anywhere in
the 4096-byte data memory space
(000h to FFFh).
The MOVSS instruction cannot use the
PCL, TOSU, TOSH or TOSL as the
destination register.
If the resultant source address points to
an Indirect Addressing register, the
value returned will be 00h. If the
resultant destination address points to
an Indirect Addressing register, the
instruction will execute as a NOP.
Words: 2
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Determine
source addr
Determine
source addr
Read
source reg
Decode Determine
dest addr
Determine
dest addr
Write
to dest reg
Example: MOVSS [05h], [06h]
Before Instruction
FSR2 = 80h
Contents
of 85h = 33h
Contents
of 86h = 11h
After Instruction
FSR2 = 80h
Contents
of 85h = 33h
Contents
of 86h = 33h
PUSHL Store Literal at FSR2, Decrement FSR2
Syntax: PUSHL k
Operands: 0k 255
Operation: k (FSR2),
FSR2 – 1 FSR2
Status Affected: None
Encoding: 1111 1010 kkkk kkkk
Description: The 8-bit literal ‘k’ is written to the data
memory address specified by FSR2.
FSR2 is decremented by 1 after the
operation.
This instruction allows users to push
values onto a software stack.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read ‘k’ Process
data
Write to
destination
Example: PUSHL 08h
Before Instruction
FSR2H:FSR2L = 01ECh
Memory (01ECh) = 00h
After Instruction
FSR2H:FSR2L = 01EBh
Memory (01ECh) = 08h
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SUBFSR Subtract Literal from FSR
Syntax: SUBFSR f, k
Operands: 0 k 63
f [ 0, 1, 2 ]
Operation: FSRf – k FSRf
Status Affected: None
Encoding: 1110 1001 ffkk kkkk
Description: The 6-bit literal ‘k’ is subtracted from
the contents of the FSR specified
by ‘f’.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: SUBFSR 2, 23h
Before Instruction
FSR2 = 03FFh
After Instruction
FSR2 = 03DCh
SUBULNK Subtract Literal from FSR2 and Return
Syntax: SUBULNK k
Operands: 0 k 63
Operation: FSR2 – k FSR2,
(TOS) PC
Status Affected: None
Encoding: 1110 1001 11kk kkkk
Description: The 6-bit literal ‘k’ is subtracted from the
contents of the FSR2. A RETURN is then
executed by loading the PC with the
TOS.
The instruction takes two cycles to
execute; a NOP is performed during the
second cycle.
This may be thought of as a special case
of the SUBFSR instruction, where f = 3
(binary ‘11’); it operates only on FSR2.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
No
Operation
No
Operation
No
Operation
No
Operation
Example: SUBULNK 23h
Before Instruction
FSR2 = 03FFh
PC = 0100h
After Instruction
FSR2 = 03DCh
PC = (TOS)
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DS30575A-page 622 2012 Microchip Technology Inc.
29.2.3 BYTE-ORIENTED AND
BIT-ORIENTED INSTRUCTIONS IN
INDEXED LITERAL OFFSET MODE
In addition to eight new commands in the extended set,
enabling the extended instruction set also enables
Indexed Literal Offset Addressing (Section 6.6.1
“Indexed Addressing with Literal Offset”). This has
a significant impact on the way that many commands of
the standard PIC18 instruction set are interpreted.
When the extended set is disabled, addresses embed-
ded in opcodes are treated as literal memory locations:
either as a location in the Access Bank (a = 0) or in a
GPR bank designated by the BSR (a = 1). When the
extended instruction set is enabled and a = 0, however,
a file register argument of 5Fh or less is interpreted as
an offset from the pointer value in FSR2 and not as a
literal address. For practical purposes, this means that
all instructions that use the Access RAM bit as an
argument – that is, all byte-oriented and bit-oriented
instructions, or almost half of the core PIC18 instruc-
tions – may behave differently when the extended
instruction set is enabled.
When the content of FSR2 is 00h, the boundaries of the
Access RAM are essentially remapped to their original
values. This may be useful in creating backward
compatible code. If this technique is used, it may be
necessary to save the value of FSR2 and restore it
when moving back and forth between C and assembly
routines in order to preserve the Stack Pointer. Users
must also keep in mind the syntax requirements of the
extended instruction set (see Section 29.2.3.1
“Extended Instruction Syntax with Standard PIC18
Commands”).
Although the Indexed Literal Offset mode can be very
useful for dynamic stack and pointer manipulation, it
can also be very annoying if a simple arithmetic opera-
tion is carried out on the wrong register. Users who are
accustomed to the PIC18 programming must keep in
mind, that when the extended instruction set is
enabled, register addresses of 5Fh or less are used for
Indexed Literal Offset Addressing.
Representative examples of typical byte-oriented and
bit-oriented instructions in the Indexed Literal Offset
mode are provided on the following page to show how
execution is affected. The operand conditions shown in
the examples are applicable to all instructions of these
types.
29.2.3.1 Extended Instruction Syntax with
Standard PIC18 Commands
When the extended instruction set is enabled, the file
register argument ‘f’ in the standard byte-oriented and
bit-oriented commands is replaced with the literal offset
value ‘k’. As already noted, this occurs only when ‘f’ is
less than or equal to 5Fh. When an offset value is used,
it must be indicated by square brackets (“[ ]”). As with
the extended instructions, the use of brackets indicates
to the compiler that the value is to be interpreted as an
index or an offset. Omitting the brackets, or using a
value greater than 5Fh within the brackets, will
generate an error in the MPASM™ Assembler.
If the index argument is properly bracketed for Indexed
Literal Offset Addressing, the Access RAM argument is
never specified; it will automatically be assumed to be
‘0’. This is in contrast to standard operation (extended
instruction set disabled), when ‘a’ is set on the basis of
the target address. Declaring the Access RAM bit in
this mode will also generate an error in the MPASM
Assembler.
The destination argument, ‘d’, functions as before.
In the latest versions of the MPASM Assembler,
language support for the extended instruction set must
be explicitly invoked. This is done with either the
command-line option, /y, or the PE directive in the
source listing.
29.2.4 CONSIDERATIONS WHEN
ENABLING THE EXTENDED
INSTRUCTION SET
It is important to note that the extensions to the instruc-
tion set may not be beneficial to all users. In particular,
users who are not writing code that uses a software
stack may not benefit from using the extensions to the
instruction set.
Additionally, the Indexed Literal Offset Addressing
mode may create issues with legacy applications
written to the PIC18 assembler. This is because
instructions in the legacy code may attempt to address
registers in the Access Bank below 5Fh. Since these
addresses are interpreted as literal offsets to FSR2
when the instruction set extension is enabled, the
application may read or write to the wrong data
addresses.
When porting an application to the PIC18F97J94
family, it is very important to consider the type of code.
A large, re-entrant application that is written in C and
would benefit from efficient compilation will do well
when using the instruction set extensions. Legacy
applications that heavily use the Access Bank will most
likely not benefit from using the extended instruction
set.
Note: Enabling the PIC18 instruction set exten-
sion may cause legacy applications to
behave erratically or fail entirely.
2012 Microchip Technology Inc. DS30575A-page 623
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ADDWF ADD W to Indexed
(Indexed Literal Offset mode)
Syntax: ADDWF [k] {,d}
Operands: 0 k 95
d [0,1]
Operation: (W) + ((FSR2) + k) dest
Status Affected: N, OV, C, DC, Z
Encoding: 0010 01d0 kkkk kkkk
Description: The contents of W are added to the
contents of the register indicated by
FSR2, offset by the value ‘k’.
If ‘d’ is ‘0’, the result is stored in W. If ‘d’
is ‘1’, the result is stored back in
register ‘f’.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read ‘k’ Process
Data
Write to
destination
Example: ADDWF [OFST] ,0
Before Instruction
W = 17h
OFST = 2Ch
FSR2 = 0A00h
Contents
of 0A2Ch = 20h
After Instruction
W = 37h
Contents
of 0A2Ch = 20h
BSF Bit Set Indexed
(Indexed Literal Offset mode)
Syntax: BSF [k], b
Operands: 0 f 95
0 b 7
Operation: 1 ((FSR2) + k)<b>
Status Affected: None
Encoding: 1000 bbb0 kkkk kkkk
Description: Bit ‘b’ of the register indicated by FSR2,
offset by the value ‘k’, is set.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example: BSF [FLAG_OFST], 7
Before Instruction
FLAG_OFST = 0Ah
FSR2 = 0A00h
Contents
of 0A0Ah = 55h
After Instruction
Contents
of 0A0Ah = D5h
SETF Set Indexed
(Indexed Literal Offset mode)
Syntax: SETF [k]
Operands: 0 k 95
Operation: FFh ((FSR2) + k)
Status Affected: None
Encoding: 0110 1000 kkkk kkkk
Description: The contents of the register indicated by
FSR2, offset by ‘k’, are set to FFh.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read ‘k’ Process
Data
Write
register
Example: SETF [OFST]
Before Instruction
OFST = 2Ch
FSR2 = 0A00h
Contents
of 0A2Ch = 00h
After Instruction
Contents
of 0A2Ch = FFh
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DS30575A-page 624 2012 Microchip Technology Inc.
29.2.5 SPECIAL CONSIDERATIONS WITH
MICROCHIP MPLAB® IDE TOOLS
The latest versions of Microchip’s software tools have
been designed to fully support the extended instruction
set for the PIC18F97J94 Family. This includes the
MPLAB C18 C Compiler, MPASM assembly language
and MPLAB Integrated Development Environment
(IDE).
When selecting a target device for software
development, MPLAB IDE will automatically set default
Configuration bits for that device. The default setting for
the XINST Configuration bit is ‘1’, enabling the
extended instruction set and Indexed Literal Offset
Addressing. For proper execution of applications
developed to take advantage of the extended
instruction set, XINST must be set during
programming.
To develop software for the extended instruction set,
the user must enable support for the instructions and
the Indexed Addressing mode in their language tool(s).
Depending on the environment being used, this may be
done in several ways:
• A menu option or dialog box within the
environment that allows the user to configure the
language tool and its settings for the project
• A command-line option
• A directive in the source code
These options vary between different compilers,
assemblers and development environments. Users are
encouraged to review the documentation accompany-
ing their development systems for the appropriate
information.
2012 Microchip Technology Inc. DS30575A-page 625
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30.0 DEVELOPMENT SUPPORT
The PIC® microcontrollers and dsPIC® digital signal
controllers are supported with a full range of software
and hardware development tools:
• Integrated Development Environment
- MPLAB® IDE Software
• Compilers/Assemblers/Linkers
- MPLAB C Compiler for Various Device
Families
- HI-TECH C® for Various Device Families
- MPASMTM Assembler
-MPLINK
TM Object Linker/
MPLIBTM Object Librarian
- MPLAB Assembler/Linker/Librarian for
Various Device Families
• Simulators
- MPLAB SIM Software Simulator
•Emulators
- MPLAB REAL ICE™ In-Circuit Emulator
• In-Circuit Debuggers
- MPLAB ICD 3
- PICkit™ 3 Debug Express
• Device Programmers
- PICkit™ 2 Programmer
- MPLAB PM3 Device Programmer
• Low-Cost Demonstration/Development Boards,
Evaluation Kits, and Starter Kits
30.1 MPLAB Integrated Development
Environment Software
The MPLAB IDE software brings an ease of software
development previously unseen in the 8/16/32-bit
microcontroller market. The MPLAB IDE is a Windows®
operating system-based application that contains:
• A single graphical interface to all debugging tools
- Simulator
- Programmer (sold separately)
- In-Circuit Emulator (sold separately)
- In-Circuit Debugger (sold separately)
• A full-featured editor with color-coded context
• A multiple project manager
• Customizable data windows with direct edit of
contents
• High-level source code debugging
• Mouse over variable inspection
• Drag and drop variables from source to watch
windows
• Extensive on-line help
• Integration of select third party tools, such as
IAR C Compilers
The MPLAB IDE allows you to:
• Edit your source files (either C or assembly)
• One-touch compile or assemble, and download to
emulator and simulator tools (automatically
updates all project information)
• Debug using:
- Source files (C or assembly)
- Mixed C and assembly
- Machine code
MPLAB IDE supports multiple debugging tools in a
single development paradigm, from the cost-effective
simulators, through low-cost in-circuit debuggers, to
full-featured emulators. This eliminates the learning
curve when upgrading to tools with increased flexibility
and power.
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DS30575A-page 626 2012 Microchip Technology Inc.
30.2 MPLAB C Compilers for Various
Device Families
The MPLAB C Compiler code development systems
are complete ANSI C compilers for Microchip’s PIC18,
PIC24 and PIC32 families of microcontrollers and the
dsPIC30 and dsPIC33 families of digital signal control-
lers. These compilers provide powerful integration
capabilities, superior code optimization and ease of
use.
For easy source level debugging, the compilers provide
symbol information that is optimized to the MPLAB IDE
debugger.
30.3 HI-TECH C for Various Device
Families
The HI-TECH C Compiler code development systems
are complete ANSI C compilers for Microchip’s PIC
family of microcontrollers and the dsPIC family of digital
signal controllers. These compilers provide powerful
integration capabilities, omniscient code generation
and ease of use.
For easy source level debugging, the compilers provide
symbol information that is optimized to the MPLAB IDE
debugger.
The compilers include a macro assembler, linker, pre-
processor, and one-step driver, and can run on multiple
platforms.
30.4 MPASM Assembler
The MPASM Assembler is a full-featured, universal
macro assembler for PIC10/12/16/18 MCUs.
The MPASM Assembler generates relocatable object
files for the MPLINK Object Linker, Intel® standard HEX
files, MAP files to detail memory usage and symbol
reference, absolute LST files that contain source lines
and generated machine code and COFF files for
debugging.
The MPASM Assembler features include:
• Integration into MPLAB IDE projects
• User-defined macros to streamline
assembly code
• Conditional assembly for multi-purpose
source files
• Directives that allow complete control over the
assembly process
30.5 MPLINK Object Linker/
MPLIB Object Librarian
The MPLINK Object Linker combines relocatable
objects created by the MPASM Assembler and the
MPLAB C18 C Compiler. It can link relocatable objects
from precompiled libraries, using directives from a
linker script.
The MPLIB Object Librarian manages the creation and
modification of library files of precompiled code. When
a routine from a library is called from a source file, only
the modules that contain that routine will be linked in
with the application. This allows large libraries to be
used efficiently in many different applications.
The object linker/library features include:
• Efficient linking of single libraries instead of many
smaller files
• Enhanced code maintainability by grouping
related modules together
• Flexible creation of libraries with easy module
listing, replacement, deletion and extraction
30.6 MPLAB Assembler, Linker and
Librarian for Various Device
Families
MPLAB Assembler produces relocatable machine
code from symbolic assembly language for PIC24,
PIC32 and dsPIC devices. MPLAB C Compiler uses
the assembler to produce its object file. The assembler
generates relocatable object files that can then be
archived or linked with other relocatable object files and
archives to create an executable file. Notable features
of the assembler include:
• Support for the entire device instruction set
• Support for fixed-point and floating-point data
• Command line interface
• Rich directive set
• Flexible macro language
• MPLAB IDE compatibility
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30.7 MPLAB SIM Software Simulator
The MPLAB SIM Software Simulator allows code
development in a PC-hosted environment by simulat-
ing the PIC MCUs and dsPIC® DSCs on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a comprehensive stimulus controller. Registers can be
logged to files for further run-time analysis. The trace
buffer and logic analyzer display extend the power of
the simulator to record and track program execution,
actions on I/O, most peripherals and internal registers.
The MPLAB SIM Software Simulator fully supports
symbolic debugging using the MPLAB C Compilers,
and the MPASM and MPLAB Assemblers. The soft-
ware simulator offers the flexibility to develop and
debug code outside of the hardware laboratory envi-
ronment, making it an excellent, economical software
development tool.
30.8 MPLAB REAL ICE In-Circuit
Emulator System
MPLAB REAL ICE In-Circuit Emulator System is
Microchip’s next generation high-speed emulator for
Microchip Flash DSC and MCU devices. It debugs and
programs PIC® Flash MCUs and dsPIC® Flash DSCs
with the easy-to-use, powerful graphical user interface of
the MPLAB Integrated Development Environment (IDE),
included with each kit.
The emulator is connected to the design engineer’s PC
using a high-speed USB 2.0 interface and is connected
to the target with either a connector compatible with in-
circuit debugger systems (RJ11) or with the new high-
speed, noise tolerant, Low-Voltage Differential Signal
(LVDS) interconnection (CAT5).
The emulator is field upgradable through future firmware
downloads in MPLAB IDE. In upcoming releases of
MPLAB IDE, new devices will be supported, and new
features will be added. MPLAB REAL ICE offers
significant advantages over competitive emulators
including low-cost, full-speed emulation, run-time
variable watches, trace analysis, complex breakpoints, a
ruggedized probe interface and long (up to three meters)
interconnection cables.
30.9 MPLAB ICD 3 In-Circuit Debugger
System
MPLAB ICD 3 In-Circuit Debugger System is Micro-
chip's most cost effective high-speed hardware
debugger/programmer for Microchip Flash Digital Sig-
nal Controller (DSC) and microcontroller (MCU)
devices. It debugs and programs PIC® Flash microcon-
trollers and dsPIC® DSCs with the powerful, yet easy-
to-use graphical user interface of MPLAB Integrated
Development Environment (IDE).
The MPLAB ICD 3 In-Circuit Debugger probe is con-
nected to the design engineer's PC using a high-speed
USB 2.0 interface and is connected to the target with a
connector compatible with the MPLAB ICD 2 or MPLAB
REAL ICE systems (RJ-11). MPLAB ICD 3 supports all
MPLAB ICD 2 headers.
30.10 PICkit 3 In-Circuit Debugger/
Programmer and
PICkit 3 Debug Express
The MPLAB PICkit 3 allows debugging and program-
ming of PIC® and dsPIC® Flash microcontrollers at a
most affordable price point using the powerful graphical
user interface of the MPLAB Integrated Development
Environment (IDE). The MPLAB PICkit 3 is connected
to the design engineer's PC using a full speed USB
interface and can be connected to the target via an
Microchip debug (RJ-11) connector (compatible with
MPLAB ICD 3 and MPLAB REAL ICE). The connector
uses two device I/O pins and the reset line to imple-
ment in-circuit debugging and In-Circuit Serial Pro-
gramming™.
The PICkit 3 Debug Express include the PICkit 3, demo
board and microcontroller, hookup cables and CDROM
with user’s guide, lessons, tutorial, compiler and
MPLAB IDE software.
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DS30575A-page 628 2012 Microchip Technology Inc.
30.11 PICkit 2 Development
Programmer/Debugger and
PICkit 2 Debug Express
The PICkit™ 2 Development Programmer/Debugger is
a low-cost development tool with an easy to use inter-
face for programming and debugging Microchip’s Flash
families of microcontrollers. The full featured
Windows® programming interface supports baseline
(PIC10F, PIC12F5xx, PIC16F5xx), midrange
(PIC12F6xx, PIC16F), PIC18F, PIC24, dsPIC30,
dsPIC33, and PIC32 families of 8-bit, 16-bit, and 32-bit
microcontrollers, and many Microchip Serial EEPROM
products. With Microchip’s powerful MPLAB Integrated
Development Environment (IDE) the PICkit™ 2
enables in-circuit debugging on most PIC® microcon-
trollers. In-Circuit-Debugging runs, halts and single
steps the program while the PIC microcontroller is
embedded in the application. When halted at a break-
point, the file registers can be examined and modified.
The PICkit 2 Debug Express include the PICkit 2, demo
board and microcontroller, hookup cables and CDROM
with user’s guide, lessons, tutorial, compiler and
MPLAB IDE software.
30.12 MPLAB PM3 Device Programmer
The MPLAB PM3 Device Programmer is a universal,
CE compliant device programmer with programmable
voltage verification at VDDMIN and VDDMAX for
maximum reliability. It features a large LCD display
(128 x 64) for menus and error messages and a modu-
lar, detachable socket assembly to support various
package types. The ICSP™ cable assembly is included
as a standard item. In Stand-Alone mode, the MPLAB
PM3 Device Programmer can read, verify and program
PIC devices without a PC connection. It can also set
code protection in this mode. The MPLAB PM3
connects to the host PC via an RS-232 or USB cable.
The MPLAB PM3 has high-speed communications and
optimized algorithms for quick programming of large
memory devices and incorporates an MMC card for file
storage and data applications.
30.13 Demonstration/Development
Boards, Evaluation Kits, and
Starter Kits
A wide variety of demonstration, development and
evaluation boards for various PIC MCUs and dsPIC
DSCs allows quick application development on fully func-
tional systems. Most boards include prototyping areas for
adding custom circuitry and provide application firmware
and source code for examination and modification.
The boards support a variety of features, including LEDs,
temperature sensors, switches, speakers, RS-232
interfaces, LCD displays, potentiometers and additional
EEPROM memory.
The demonstration and development boards can be
used in teaching environments, for prototyping custom
circuits and for learning about various microcontroller
applications.
In addition to the PICDEM™ and dsPICDEM™ demon-
stration/development board series of circuits, Microchip
has a line of evaluation kits and demonstration software
for analog filter design, KEELOQ® security ICs, CAN,
IrDA®, PowerSmart battery management, SEEVAL®
evaluation system, Sigma-Delta ADC, flow rate
sensing, plus many more.
Also available are starter kits that contain everything
needed to experience the specified device. This usually
includes a single application and debug capability, all
on one board.
Check the Microchip web page (www.microchip.com)
for the complete list of demonstration, development
and evaluation kits.
2012 Microchip Technology Inc. DS30575A-page 629
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31.0 ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings(†)
Ambient temperature under bias.............................................................................................................-40°C to +100°C
Storage temperature .............................................................................................................................. -65°C to +150°C
Voltage on MCLR with respect to VSS.......................................................................................................... -0.3V to 5.5V
Voltage on any digital only I/O pin with respect to VSS (except VDD)........................................................... -0.3V to 5.5V
Voltage on any combined digital and analog pin with respect to VSS (except VDD and MCLR)...... -0.3V to (VDD + 0.3V)
Voltage on VBAT with respect to VSS......................................................................................................... -0.3V to 3.66V
Voltage on VUSB3V3 with respect to VSS ........................................................................................ (VDD – 0.3V) to +4.0V
Voltage on VDD with respect to VSS .......................................................................................................... -0.3V to 3.66V
Voltage on D+ or D- with respect to VSS – 0W source impedance (Note 2)............................ -0.5V to (VUSB3V3 + 0.5V)
Source impedance 28W, VUSB3V3 3.0V).............................................................................................. -1.0V to +4.6V
Total power dissipation (Note 1).................................................................................................................................. 1W
Maximum current out of VSS pin ...........................................................................................................................300 mA
Maximum current into VDD pin ..............................................................................................................................250 mA
Input clamp current, IIK (VI < 0 or VI > VDD)..........................................................................................................±20 mA
Output clamp current, IOK (VO < 0 or VO > VDD) .................................................................................................. ±20 mA
Maximum output current sunk by any I/O pins........................................................................................................25 mA
Maximum output current sourced by any I/O pins...................................................................................................25 mA
Maximum current sunk byall ports combined.......................................................................................................200 mA
Maximum current sourced by all ports combined..................................................................................................200 mA
Note 1: Power dissipation is calculated as follows:
Pdis = VDD x {IDD – IOH} + {(VDD – VOH) x IOH} + (VOL x IOL)
2: The original “USB 2.0 Specification” indicated that USB devices should withstand 24-hour short circuits of
D+ or D- to VBUS voltages. This requirement was later removed in an engineering change notice (ECN) sup-
plement to the USB specifications, which supersedes the original specifications. PIC18F97J94 family
devices will typically be able to survive this short circuit test, but it is recommended to adhere to the absolute
maximum specified here to avoid damaging the device.
†NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above
those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions
for extended periods may affect device reliability.
PIC18F97J94 FAMILY
DS30575A-page 630 2012 Microchip Technology Inc.
FIGURE 31-1: VOLTAGE-FREQUENCY GRAPH, REGULATOR DISABLED (INDUSTRIAL)(1,2)
Frequency
Voltage (VDD)
4V
2V
64 MHz
3.75V
3.25V
2.5V
3.6V
4 MHz
3V
Note 1: When the USB module is enabled, VUSB3V3 and VDD should be connected together and provided
3.0V-3.6V. When the USB module is not enabled, VUSB3V3 and VDD should still be connected
together.
2: VCAP (nominal on-chip regulator output voltage) = 1.8V.
PIC18F97J94 Family
2012 Microchip Technology Inc. DS30575A-page 631
PIC18F97J94 FAMILY
31.1 DC Characteristics: Supply Voltage
PIC18F97J94 (Industrial)
PIC18F97J94
(Industrial)
Standard Operating Conditions: 2V to 3.6V (unless otherwise stated)
Operating temperature -40°C TA +85°C
Param
No. Symbol Characteristic Min Typ Max Units Conditions
D001 VDD Supply Voltage 2.0 — 3.6 V
D001C AVDD Analog Supply Voltage VDD – 0.3 — VDD + 0.3 V
D001D AVSS Analog Ground Potential VSS – 0.3 — VSS + 0.3 V
D001E VUSB3V3USB Supply Voltage 3 3.3 3.6 V USB module enabled(3)
D002 VDR RAM Data Retention
Voltage(1)
1.2 — — V
D003 VPOR VDD/VBAT Start Voltage
to Ensure Internal
Power-on Reset Signal
— — 0.7 V See Section 5.2 “Power-on
Reset (POR)” for details
D004 SVDD VDD/VBAT Rise Rate
to Ensure Internal
Power-on Reset Signal
0.05 — — V/ms See Section 5.2 “Power-on
Reset (POR)” for details
D005 BVDD Brown-out Reset Voltage
BORV = 1(2)
BORV = 0
1.8
2.0
1.88
2.05
1.95
2.20
V
V
D006 VVDDBOR 1.4V 2.0 V
D007 VVBATBOR 1.4V 1.95 V
D008 VDSBOR 1.8
Note 1: This is the limit to which VDD can be lowered in Sleep mode, or during a device Reset, without losing RAM data.
2: The device will operate normally until Brown-out Reset occurs, even though VDD may be below VDDMIN.
3: VUSB3V3 should be connected to VDD.
PIC18F97J94 FAMILY
DS30575A-page 632 2012 Microchip Technology Inc.
TABLE 31-1: DC CHARACTERISTICS: POWER-DOWN AND SUPPLY CURRENT
PIC18F97J94 FAMILY (INDUSTRIAL)
31.2 DC Characteristics: Power-Down and Supply Current
PIC18F97J94 (Industrial)
PIC18F97J94 Family
(Industrial)
Standard Operating Conditions: 2V to 3.6V (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
Param
No. Typ(1)Max Units Conditions
DC60 3.7 7.0 µA -40°C
2.0V
Sleep(2)
3.7 7.0 µA +25°C
5.0 9.0 µA +60°C
9.0 18 µA +85°C
3.7 8.0 µA -40°C
3.3V
3.7 8.0 µA +25°C
5.0 11.0 µA +60°C
10 20 µA +85°C
DC61 0.07 0.55 µA -40°C
2.0V
Retention Sleep or
Retention Deep Sleep(3)
0.09 0.55 µA +25°C
2.0 3.2 µA +60°C
7.0 8.5 µA +85°C
0.10 0.65 µA -40°C
3.3V
0.15 0.65 µA +25°C
2.0 3.5 µA +60°C
7.2 9.0 µA +85°C
DC70 0.06 0.5 µA -40°C
2.0V
Deep Sleep
0.08 0.5 µA +25°C
0.21 0.8 µA +60°C
0.41 1.5 µA +85°C
0.09 0.6 µA -40°C
3.3V
0.11 0.6 µA +25°C
0.42 1.2 µA +60°C
0.8 4.8 µA +85°C
0.4 3.0 µA -40°C TO +85°C 0 RTCC with VBAT mode (LPRC or
SOSC)(4)
Note 1: Data in the Typical column is at 3.3V, 25°C; typical parameters are for design guidance only and are not tested.
2: Retention regulator is disabled; SRETEN (RCON4<4>= 0), RETEN (CONFIG7L<0>= 1).
3: Retention regulator is enabled; SRETEN (RCON4<4> = 1), RETEN (CONFIG7L<0> = 0).
4: VBAT pin is connected to the battery and RTCC is running with VDD = 0.
Param
No. Device Typ Max Units Conditions
Supply Current (IDD)
All Devices
22 55 µA -40°C to +85°C VDD = 2.0V FOSC = 31 kHz, RC_RUN
23 56 µA -40°C to +85°C VDD = 3.3V
21 54 µA -40°C to +85°C VDD = 2.0V FOSC = 31 kHz, RC_IDLE
22 55 µA -40°C to +85°C VDD = 3.3V
2012 Microchip Technology Inc. DS30575A-page 633
PIC18F97J94 FAMILY
TABLE 31-2:
DC CHARACTERISTICS: POWER-DOWN AND SUPPLY CURRENT
PIC18F97J94 FAMILY (INDUSTRIAL)
TABLE 31-3:
DC CHARACTERISTICS: POWER-DOWN AND SUPPLY CURRENT
PIC18F97J94 FAMILY (INDUSTRIAL)
Param
No. Device Typ Max Units Conditions
Supply Current (IDD)
All Devices
22 55 µA -40°C to +85°C VDD = 2.0V FOSC = 32 kHz, SEC_RUN
23 56 µA -40°C to +85°C VDD = 3.3V
21 54 µA -40°C to +85°C VDD =2.0V FOSC = 32 kHz, SEC_IDLE
22 55 µA -40°C to +85°C VDD = 3.3V
Param
No. Device Typ Max Units Conditions
Supply Current (IDD)
All Devices
325 430 µA -40°C to +85°C VDD = 2.0V FOSC = 1 MHz, RC_RUN
325 430 µA -40°C to +85°C VDD = 3.3V
540 700 µA -40°C to +85°C VDD = 2.0V FOSC = 4 MHz, RC_RUN
540 700 µA -40°C to +85°C VDD = 3.3V
820 1000 µA -40°C to +85°C VDD = 2.0V FOSC = 8 MHz, RC_RUN
825 1000 µA -40°C to +85°C VDD = 3.3V
275 370 µA -40°C to +85°C VDD = 2.0V FOSC = 1 MHz, RC_IDLE
275 370 µA -40°C to +85°C VDD = 3.3V
345 440 µA -40°C to +85°C VDD = 2.0V FOSC = 4 MHz, RC_IDLE
345 440 µA -40°C to +85°C VDD = 3.3V
435 620 µA -40°C to +85°C VDD = 2.0V FOSC = 8 MHz, RC_IDLE
435 620 µA -40°C to +85°C VDD = 3.3V
PIC18F97J94 FAMILY
DS30575A-page 634 2012 Microchip Technology Inc.
TABLE 31-4:
DC CHARACTERISTICS: POWER-DOWN AND SUPPLY CURRENT
PIC18F97J94 FAMILY (INDUSTRIAL)
Param
No. Device Typ Max Units Conditions
Supply Current (IDD)
All Devices
100 150 µA -40°C to +85°C VDD = 2.0V FOSC = 1 MHz, PRI_RUN mode,
EC Oscillator
105 155 µA -40°C to +85°C VDD = 3.3V
330 390 µA -40°C to +85°C VDD = 2.0V FOSC = 4 MHz, PRI_RUN mode,
EC Oscillator
340 405 µA -40°C to +85°C VDD = 3.3V
5.0 5.5 mA -40°C to +85°C VDD = 2.0V FOSC = 64 MHz, PRI_RUN mode,
EC Oscillator
5.0 5.5 mA -40°C to +85°C VDD = 3.3V
5.7 6.5 mA -40°C to +85°C VDD = 2.0V FOSC = 64 MHz, PRI_RUN mode,
8 MHz EC Oscillator with 96 MHz
or 8X PLL
5.7 7.0 mA -40°C to +85°C VDD = 3.3V
52 90 µA -40°C to +85°C VDD = 2.0V FOSC = 1 MHz, PRI_IDLE mode,
EC Oscillator
66 95 µA -40°C to +85°C VDD = 3.3V
135 185 µA -40°C to +85°C VDD = 2.0V FOSC = 4 MHz, PRI_IDLE mode,
EC Oscillator
145 195 µA -40°C to +85°C VDD = 3.3V
1.8 2.6 mA -40°C to +85°C VDD = 2.0V FOSC = 64 MHz, PRI_IDLE mode,
EC Oscillator
2.0 2.8 mA -40°C to +85°C VDD = 3.3V
2.3 2.9 mA -40°C to +85°C VDD = 2.0V FOSC = 64 MHz, PRI_IDLE mode,
8 MHz EC Oscillator with 96 MHz
or 8X PLL
2.4 3.0 mA -40°C to +85°C VDD = 3.3V
2012 Microchip Technology Inc. DS30575A-page 635
PIC18F97J94 FAMILY
TABLE 31-5:
DC CHARACTERISTICS: POWER-DOWN AND SUPPLY CURRENT
PIC18F97J94 FAMILY (INDUSTRIAL)
TABLE 31-6: D
C CHARACTERISTICS: POWER-DOWN AND SUPPLY CURRENT
PIC18F97J94 FAMILY (INDUSTRIAL)
Param
No. Device Typ(1)Max Units Conditions
Module Differential Currents (ΔIWDT, ΔIBOR, ΔIHLVD, ΔIDSBOR, ΔIDSWDT, ΔIOSCB, ΔIADRC, ΔILCD, ΔIUSB)
D020 (ΔIWDT)Watchdog Timer 0.4 1 µA -40°C to +85°C VDD = 2.0V
0.4 1 µA -40°C to +85°C VDD = 3.3V
D021 (ΔIBOR)Brown-out Reset 4 8 µA -40°C to +85°C VDD = 2.0V High-Power BOR
5 9 µA -40°C to +85°C VDD = 3.3V
D022 (ΔIHLVD)High/Low-Voltage
Detect
4 8 µA -40°C to +85°C VDD = 2.0V
5 9 µA -40°C to +85°C VDD = 3.3V
D023 (ΔIDSBOR)Deep Sleep BOR 135 480 nA -40°C to +85°C VDD = 2.0V
to 3.3V ΔDeep Sleep BOR(2)
D024 (ΔIDSWDT)Deep Sleep
Watchdog Timer
290 480 nA -40°C to +85°C VDD = 2.0V
to 3.3V ΔDeep Sleep WDT(2)
D025 (ΔIOSCB)Real-Time Clock/
Calendar with
Timer1 Oscillator
0.38 1 µA -40°C to +85°C VDD = 2.0V Sleep mode 32.768 kHz,
T1OSCEN = 1, LPT1OSC = 0
0.55 1 µA -40°C to +85°C VDD = 3.3V
D027 (ΔILCD)LCD Module 0.6 4 µA -40°C to +85°C VDD = 3.3V ΔLCD External/Internal,
1/8 MUX, 1/3 Bias(2,3)
6 30 µA -40°C to +85°C VDD = 2.0V ΔLCD Charge Pump,
1/8 MUX, 1/3 Bias(2,4)
7 40 µA -40°C to +85°C VDD = 3.3V
D028 (ΔIADRC)A/D with RC 330 500 µA -40°C to +85°C VDD = 2.0V
385 500 µA -40°C to +85°C VDD = 3.3V
D028 (ΔIUSB)USB Module 1 2 mA -40°C to +85°C VDD and
VUSB3V3 = 3.3V
USB enabled, no cable connected;
traffic makes a large difference(5)
Note 1: Data in the Typical column is at 3.3V, 25°C unless otherwise stated. Parameters are for design guidance only and are not
tested.
2: Incremental current while the module is enabled and running.
3: LCD is enabled and running, no glass is connected; the resistor ladder current is not included.
4: LCD is enabled and running, no glass is connected.
5: This is the module differential current when the USB module is enabled and clocked at 48 MHz, but with no USB cable
attached. When the USB cable is attached, or data is being transmitted, the current consumption may be much higher (see
Section 27.6.4 “USB Transceiver Current Consumption”). During USB Suspend mode (USBEN = 1, SUSPND = 1, bus
in Idle state), the USB module current will be dominated by the D+ or D- pull-up resistor. The integrated pull-up resistors use
“resistor switching” according to the resistor_ecn supplement to the “USB 2.0 Specification” and therefore, may be as low as
900Ω during Idle conditions.
DC CHARACTERISTICS Standard Operating Conditions: 3.0V < VDD < 3.6V
-40°C T
A +85°C for Industrial (unless otherwise stated)
Param
No. Sym Characteristic Min Typ Max Units Conditions
VBT Operating Voltage 2.0 — 3.6 V Battery connected to VBAT pin
VBTADC VBAT A/D Monitoring
Voltage Specification(1)1.6 — 3.6 V A/D monitoring the VBAT pin using
the internal A/D channel
Note 1: Measure A/D value using the A/D represented by the equation (Measured Voltage = ((VBAT/2)/VDD) * 1024) for
10-bit A/D; Measured Voltage = ((VBAT/2)/VDD) * 4096) for 12-bit A/D.
PIC18F97J94 FAMILY
DS30575A-page 636 2012 Microchip Technology Inc.
TABLE 31-7: D
C CHARACTERISTICS: POWER-DOWN AND SUPPLY CURRENT
PIC18F97J94 FAMILY (INDUSTRIAL)
DC CHARACTERISTICS Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
Param
No. Sym Characteristic Min Max Units Conditions
D031
D031A
D031B
D032
D033
D033A
D034
VIL Input Low Voltage
All I/O Ports:
Schmitt Trigger Buffer
RC3 and RC4
MCLR
OSC1
OSC1
SOSCI
Vss
Vss
Vss
Vss
Vss
Vss
Vss
0.2 VDD
0.3 VDD
0.8
0.2 VDD
0.2 VDD
0.2 VDD
0.3 VDD
V
V
V
V
V
V
V
2V VDD 3.6V
I2C™ enabled
SMBus enabled
LP, MS, HS modes
EC modes
D041
D041A
D041B
D042
D043
D043A
D044
VIH Input High Voltage
All I/O Ports:
Schmitt Trigger Buffer
RC3 and RC4
MCLR
OSC1
OSC1
SOSCI
0.8
0.7 VDD
2.1
0.8 VDD
0.9 VDD
0.7 VDD
0.7 VDD
5.5
5.5
5.5
VDD
VDD
VDD
VDD
V
V
V
V
V
V
V
2V VDD 3.6V
I2C™ enabled
SMBus enabled
RC mode
HS mode
D060
D061
D063
IIL Input Leakage Current(1)
I/O Ports
MCLR
OSC1
±50
—
—
±500
±500
1
nA
nA
µA
Vss VPIN VDD
Pin at high-impedance
Vss VPIN VDD
Vss VPIN VDD
D070 IPU Weak Pull-up Current
Weak Pull-up Current 50 400 µA VDD = 3.6V, VPIN = Vss
D080
D083
VOL Output Low Voltage
I/O Ports:
All Ports
OSC2/CLKO
(EC modes)
—
—
—
—
0.4
0.4
0.4
0.4
V
V
V
V
IOL = 6.6 mA, VDD = 3.6V
IOL = 5.0 mA, VDD = 2V
IOL = 6.6 mA, VDD = 3.6V
IOL = 5.0 mA, VDD = 2V
D090
D092
VOH Output High Voltage(1)
I/O Ports:
All Ports
OSC2/CLKO
(INTOSC, EC modes)
3.0
2.4
1.6
1.4
2.4
1.4
—
—
—
—
—
—
V
V
V
V
V
V
IOH = -3.0 mA, VDD = 3.6V
IOH = -6.0 mA, VDD = 3.6V
IOH = -1.0 mA, VDD = 2V
IOH = -3.0 mA, VDD = 2V
IOH = -6.0 mA, VDD = 3.6V
IOH = -1.0 mA, VDD = 2V
D100
D101
D102
COSC2
CIO
CB
Capacitive Loading Specs
on Output Pins
OSC2 Pin
All I/O Pins and OSC2
SCLx, SDAx
—
—
—
20
50
400
pF
pF
pF
In HS mode when external clock is
used to drive OSC1
To meet the AC Timing Specifications
I2C™ Specification
Note 1: Negative current is defined as current sourced by the pin.
2012 Microchip Technology Inc. DS30575A-page 637
PIC18F97J94 FAMILY
TABLE 31-8: DC CHARACTERISTICS: CTMU CURRENT SOURCE SPECIFICATIONS
TABLE 31-9: MEMORY PROGRAMMING REQUIREMENTS
DC CHARACTERISTICS Standard Operating Conditions: 2V to 3.6V
Operating temperature -40°C TA +85°C for Industrial
Param
No. Sym Characteristic Min Typ(1)Max Units Conditions
IOUT1 CTMU Current Source,
Base Range
— 550 — nA CTMUCON1<1:0> = 01
IOUT2 CTMU Current Source,
10x Range
—5.5—A CTMUCON1<1:0> = 10
IOUT3 CTMU Current Source,
100x Range
—55—A CTMUCON1<1:0> = 11
Note 1: Nominal value at center point of current trim range (CTMUCON1<7:2> = 000000).
DC CHARACTERISTICS Standard Operating Conditions
Operating temperature -40°C T
A +85°C for Industrial
Param
No. Sym Characteristic Min Typ†Max Units Conditions
Internal Program Memory
Programming Specifications(1)
D110 VPP Voltage on MCLR/VPP Pin VDD + 1.5 — 10 V (Note 2, Note 3)
D113 IDDP Supply Current During
Programming
——10mA
Program Flash Memory
D130 EPCell Endurance 1K 20K — E/W -40C to +85C
D131 VPR VDD for Read
2—3.6V
D132B VPEW Voltage for Self-Timed Erase or
Write Operations VDD
2 — 3.6 V PIC18FXXKXX devices
D133A TIW Self-Timed Write Cycle Time — 2 — ms
D133B TIE Self-Timed Block Erased Cycle
Time
—33—ms
D134 TRETD Characteristic Retention 10 — — Year Provided no other
specifications are violated
D135 IDDP Supply Current during
Programming
——10mA
D140 TWE Writes per Erase Cycle — — 1 For each physical address
† Data in “Typ” column is at 3.3V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: These specifications are for programming the on-chip program memory through the use of table write
instructions.
2: Required only if single-supply programming is disabled.
3: The MPLAB® ICD 2 does not support variable VPP output. Circuitry to limit the MPLAB ICD 2 VPP voltage
must be placed between the MPLAB ICD 2 and the target system when programming or debugging with
the MPLAB ICD 2.
PIC18F97J94 FAMILY
DS30575A-page 638 2012 Microchip Technology Inc.
TABLE 31-10: COMPARATOR SPECIFICATIONS
TABLE 31-11: COMPARATOR VOLTAGE REFERENCE SPECIFICATIONS
TABLE 31-12: INTERNAL VOLTAGE REGULATOR SPECIFICATIONS
TABLE 31-13: RC OSCILLATOR START-UP TIME
Operating Conditions: 2.0V VDD 3.6V, -40°C TA +85°C
Param
No. Sym Characteristics Min Typ Max Units Comments
D300 VIOFF Input Offset Voltage — ±5.0 40 mV
D301 VICM Input Common-Mode Voltage 0 — AVDD V
D302 CMRR Common-Mode Rejection Ratio 55 — — dB
D303 TRESP Response Time(1)—150400 ns
D304 TMC2OV Comparator Mode Change to
Output Valid*
—— 10 s
Note 1: Response time is measured with one comparator input at (AVDD – 1.5)/2, while the other input transitions
from VSS to VDD.
Operating Conditions: 2.0V VDD 3.6V, -40°C TA +85°C
Param
No. Sym Characteristics Min Typ Max Units Comments
D310 VRES Resolution VDD/32 — VDD/32 LSb
D311 VRAA Absolute Accuracy — — 3/4 LSb
D312 VRUR Unit Resistor Value (R) — 2k —
D313 TSET Settling Time(1)— — 10 s
Note 1: Settling time measured while CVRR = 1 and CVR<3:0> transitions from ‘0000’ to ‘1111’.
Operating Conditions: -40°C TA +85°C
Param
No. Sym Characteristics Min Typ Max Units Comments
VRGOUT Regulator Output Voltage — 1.8 — V
CEFC External Filter Capacitor Value 4.7 10 — F Capacitor must be
low-ESR, a low series
resistance (< 5)
AC CHARACTERISTICS Standard Operating Conditions: 2V to 3.6V (unless otherwise stated)
Operating temperature -40°C T
A +85°C for Industrial
Param
No. Characteristics Min Typ Max Units Comments
TFRC —15—µs
TLPRC —10—µs
2012 Microchip Technology Inc. DS30575A-page 639
PIC18F97J94 FAMILY
TABLE 31-14: USB MODULE SPECIFICATIONS
Operating Conditions: -40°C <TA < +85°C
Param
No. Sym Characteristics Min Typ Max Units Comments
D313 VUSB3V3USB Voltage 3 — 3.6 V Voltage on VUSB3V3 pin
must be in this range for
proper USB operation
D314 IIL Input Leakage on Pin — — ±1 µA VSS < VPIN < VDD pin at
high-impedance
D318 VDIFS Differential Input Sensitivity — — 0.2 V The difference between D+
and D- must exceed this
value while VCM is met
D319 VCM Differential Common-Mode
Range
0.8 — 2.5 V
D320 ZOUT Driver Output Impedance(1)28 — 44 Ω
D321 VOL Voltage Output Low 0 — 0.3 V 1.5 kΩ load connected to
3.6V
D322 VOH Voltage Output High 2.8 — 3.6 V 1.5 kΩ load connected to
ground
Note 1: The D+ and D- signal lines have built-in impedance matching resistors. No external resistors, capacitors
or magnetic components are necessary on the D+/D- signal paths between the PIC18F97J94 family
device and a USB cable.
PIC18F97J94 FAMILY
DS30575A-page 640 2012 Microchip Technology Inc.
31.3 AC (Timing) Characteristics
31.3.1 TIMING PARAMETER SYMBOLOGY
The timing parameter symbols have been created
following one of the following formats:
1. TppS2ppS 3. TCC:ST (I2C specifications only)
2. TppS 4. Ts (I2C specifications only)
T
F Frequency T Time
Lowercase letters (pp) and their meanings:
pp
cc CCP1 osc OSC1
ck CLKO rd RD
cs CS rw RD or WR
di SDI sc SCK
do SDO ss SS
dt Data in t0 T0CKI
io I/O port t1 T1CKI
mc MCLR wr WR
Uppercase letters and their meanings:
S
F Fall P Period
HHigh RRise
I Invalid (High-impedance) V Valid
L Low Z High-impedance
I2C only
AA output access High High
BUF Bus free Low Low
T
CC:ST (I2C specifications only)
CC
HD Hold SU Setup
ST
DAT DATA input hold STO Stop condition
STA Start condition
2012 Microchip Technology Inc. DS30575A-page 641
PIC18F97J94 FAMILY
31.3.2 TIMING CONDITIONS
The temperature and voltages specified in Table 31-15
apply to all timing specifications unless otherwise
noted. Figure 31-2 specifies the load conditions for the
timing specifications.
TABLE 31-15: TEMPERATURE AND VOLTAGE SPECIFICATIONS – AC
FIGURE 31-2: LOAD CONDITIONS FOR DEVICE TIMING SPECIFICATIONS
AC CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
Operating voltage VDD range as described in Section 31.1 and Section TABLE 31-
1:.
VDD/2
CL
RL
Pin Pin
VSS VSS
CL
RL= 464
CL= 50 pF for all pins except OSC2/CLKO/RA6
and including D and E outputs as ports
CL= 20 pF for OSC2/CLKO/RA6
Load Condition 1 Load Condition 2
PIC18F97J94 FAMILY
DS30575A-page 642 2012 Microchip Technology Inc.
31.3.3 TIMING DIAGRAMS AND SPECIFICATIONS
FIGURE 31-3: EXTERNAL CLOCK TIMING
TABLE 31-16: EXTERNAL CLOCK TIMING REQUIREMENTS
Param.
No. Symbol Characteristic Min Max Units Conditions
1A FOSC External CLKIN
Frequency(1)
DC 64 MHz EC Oscillator mode
Oscillator Frequency(1)4 16 MHz HS Oscillator mode
4 16 MHz HS + PLL Oscillator mode
1T
OSC External CLKIN Period(1)15.6 — ns EC, ECIO Oscillator mode
Oscillator Period(1)40 250 ns HS Oscillator mode
62.5 250 ns HS+PLL Oscillator mode
2T
CY Instruction Cycle Time(1)62.5 — ns TCY = 4/FOSC
3TOSL,
T
OSH
External Clock in (OSC1)
High or Low Time
10 — ns HS Oscillator mode
4T
OSR,
T
OSF
External Clock in (OSC1)
Rise or Fall Time
— 7.5 ns HS Oscillator mode
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period for all configurations
except PLL. All specified values are based on characterization data for that particular oscillator type under
standard operating conditions with the device executing code. Exceeding these specified limits may result
in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested
to operate at “min.” values with an external clock applied to the OSC1/CLKIN pin. When an external clock
input is used, the “max.” cycle time limit is “DC” (no clock) for all devices.
OSC1
CLKO
Q4 Q1 Q2 Q3 Q4 Q1
1
2
3344
2012 Microchip Technology Inc. DS30575A-page 643
PIC18F97J94 FAMILY
TABLE 31-17: PLL CLOCK TIMING SPECIFICATIONS (VDD = 2.0V TO 3.6V)(1)
TABLE 31-18: INTERNAL RC ACCURACY (FRC)
Param
No. Sym Characteristic Min Typ Max Units Conditions
F10 FOSC Oscillator Frequency Range 4—16MHzV
DD = 2.0-3.6V,
-40°C to +85°C
F11 FSYS On-Chip VCO System Frequency 16 — 64 MHz VDD = 2.0-3.6V,
-40°C to +85°C
F12 trc PLL Start-up Time (Lock Time) — — 2 ms
F13 CLK CLKOUT Stability (Jitter) -2 — +2 %
Note 1: These specifications are for x96 PLL or x8 PLL.
PIC18F97J94 Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C T
A +85°C
Param
No. Characteristics Min Typ Max Units Conditions
OA1 FRC Accuracy @ Freq = 8 MHz, 4 MHz, 2 MHz, 1 MHz, 500 kHz, 250 kHz, 125 kHz, 31.25 kHz(1)
-0.5 — +0.5 % +25°C VDD = 3.0-3.6V
-1.5 — +1.5 % -40°C to +85°C VDD = 2.0-3.6V
OA2 LPRC Accuracy @ Freq = 31 kHz
-20 — 20 % -40°C to +85°C VDD = 2.0-3.6V
Note 1: Frequency is calibrated at +25°C. OSCTUNE register can be used to compensate for temperature drift.
PIC18F97J94 FAMILY
DS30575A-page 644 2012 Microchip Technology Inc.
FIGURE 31-4: CLKO AND I/O TIMING
TABLE 31-19: CLKO AND I/O TIMING REQUIREMENTS
Param
No. Symbol Characteristic Min Typ Max Units Conditions
10 TOSH2CKLOSC1 to CLKO —75200ns(Note 1)
11 TOSH2CKHOSC1 to CLKO —75200ns(Note 1)
12 TCKRCLKO Rise Time — 15 30 ns(Note 1)
13 TCKFCLKO Fall Time — 15 30 ns(Note 1)
14 TCKL2IOVCLKO to Port Out Valid — — 0.5 TCY + 20 ns
15 TIOV2CKH Port In Valid before CLKO 0.25 TCY + 25 — — ns
16 TCKH2IOI Port In Hold after CLKO 0——ns
17 TOSH2IOVOSC1 (Q1 cycle) to Port Out Valid — 50 150 ns
18 TOSH2IOIOSC1 (Q2 cycle) to Port Input Invalid
(I/O in hold time)
100 — — ns
19 TIOV2OSH Port Input Valid to OSC1
(I/O in setup time)
0——ns
20 TIOR Port Output Rise Time — 10 25 ns
21 TIOF Port Output Fall Time — 10 25 ns
22†TINP INTx Pin High or Low Time 20 — — ns
23†TRBP RB<7:4> Change INTx High or Low
Time
TCY ——ns
† These parameters are asynchronous events not related to any internal clock edges.
Note 1: Measurements are taken in EC mode, where CLKO output is 4 x TOSC.
Note: Refer to Figure 31-2 for load conditions.
OSC1
CLKO
I/O Pin
(Input)
I/O Pin
(Output)
Q4 Q1 Q2 Q3
10
13
14
17
20, 21
19 18
15
11
12
16
Old Value New Value
2012 Microchip Technology Inc. DS30575A-page 645
PIC18F97J94 FAMILY
FIGURE 31-5: PROGRAM MEMORY FETCH TIMING DIAGRAM (8-BIT)
TABLE 31-20: PROGRAM MEMORY FETCH TIMING REQUIREMENTS (8-BIT)
Param
No Symbol Characteristics Min Typ Max Units
150 TadV2aIL Address Out Valid to ALE (address setup time) 0.25 T
CY – 10 — — ns
151 TaIL2adl ALE to Address Out Invalid (address hold time) 5 — — ns
153 BA01 BA0 to Most Significant Data Valid 0.125 TCY ——ns
154 BA02 BA0 to Least Significant Data Valid 0.125 TCY ——ns
155 TaIL2oeL ALE to OE 0.125 TCY ——ns
161 ToeH2adD OE to A/D Driven 0.125 TCY – 5 — — ns
162 TadV2oeH Least Significant Data Valid Before OE
(data setup time)
20 — — ns
162A TadV2oeH Most Significant Data Valid Before OE
(data setup time)
0.25 TCY + 20 — — ns
163 ToeH2adI OE to Data in Invalid (data hold time) 0 — — ns
166 TaIH2aIH ALE to ALE (cycle time) — TCY —ns
167 TACC Address Valid to Data Valid 0.5 TCY – 10 — — ns
168 Toe OE to Data Valid — — 0.125 TCY + 5 ns
170 TubH2oeH BA0 = 0 Valid Before OE 0.25 TCY ——ns
170A TubL2oeH BA0 = 1 Valid Before OE 0.5 TCY ——ns
Q1 Q2 Q3 Q4 Q1 Q2
OSC1
ALE
OE
Address Data
170
161
162
AD<7:0> Address
Address
A<19:8> Address
162A
BA0
Data
170A
151
150
166
167
155
153
163
154
168
CE
Note: Fmax = 25 MHz in 8-Bit External Memory mode.
PIC18F97J94 FAMILY
DS30575A-page 646 2012 Microchip Technology Inc.
FIGURE 31-6: PROGRAM MEMORY READ TIMING DIAGRAM
TABLE 31-21: CLKO AND I/O TIMING REQUIREMENTS
Param.
No Symbol Characteristics Min Typ Max Units
150 TadV2alL Address Out Valid to ALE
(address setup time)
0.25 TCY – 10 — — ns
151 TalL2adl ALE to Address Out Invalid
(address hold time)
5——ns
155 TalL2oeL ALE to OE 10 0.125 TCY —ns
160 TadZ2oeL A/D High-Z to OE (bus release to OE)0——ns
161 ToeH2adD OE to A/D Driven 0.125 TCY – 5 — — ns
162 TadV2oeH LS Data Valid before OE (data setup time) 20 — — ns
163 ToeH2adl OE to Data In Invalid (data hold time) 0 — — ns
164 TalH2alL ALE Pulse Width — 0.25 TCY —ns
165 ToeL2oeH OE Pulse Width 0.5 TCY – 5 0.5 TCY —ns
166 TalH2alH ALE to ALE (cycle time) — TCY —ns
167 Tacc Address Valid to Data Valid 0.75 TCY – 25 — — ns
168 Toe OE to Data Valid — 0.5 TCY – 25 ns
169 TalL2oeH ALE to OE 0.625 TCY – 10 — 0.625 TCY + 10 ns
171 TalH2csL Chip Enable Active to ALE 0.25 TCY – 20 — — ns
171A TubL2oeH A/D Valid to Chip Enable Active — — 10 ns
Q1 Q2 Q3 Q4 Q1 Q2
OSC1
ALE
OE
Address Data from External
166
160
165
161
151 162
163
AD<15:0>
168
155
Address
Address
150
A<19:16> Address
BA0
CE
171
171A
Operating Conditions: 2.0V < VCC < 3.6V, -40°C < TA < +125°C unless otherwise stated.
164
167
169
2012 Microchip Technology Inc. DS30575A-page 647
PIC18F97J94 FAMILY
FIGURE 31-7: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND
POWER-UP TIMER TIMING
FIGURE 31-8: BROWN-OUT RESET TIMING
TABLE 31-22: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET REQUIREMENTS
Param.
No. Symbol Characteristic Min Typ Max Units Conditions
30 TmcL MCLR Pulse Width (low) 2 — — s
31 TWDT Watchdog Timer Time-out Period (no
postscaler)
—4.00— ms
32 TOST Oscillation Start-up Timer Period 1024 TOSC — 1024 TOSC —TOSC = OSC1 period
33 TPWRT Power-up Timer Period — 300 µs — s
34 TIOZ I/O High-Impedance from MCLR Low
or Watchdog Timer Reset
—2—s
35 TBOR Brown-out Reset Pulse Width 200 — — sVDD BVDD (see D005)
36 TIRVST Time for Internal Reference
Voltage to become Stable
—25—s
37 THLVD High/Low-Voltage Detect Pulse Width 200 — — sVDD VHLVD
38 TCSD CPU Start-up Time 5 — 10 s
39 TIOBST Time for INTOSC to Stabilize — 1 — s
VDD
MCLR
Internal
POR
PWRT
Time-out
Oscillator
Time-out
Internal
Reset
Watchdog
Timer
Reset
33
32
30
31
34
I/O pins
34
Note: Refer to Figure 31-2 for load conditions.
VDD BVDD
35
VBGAP = 1.2V
VIRVST
Enable Internal
Internal Reference 36
Reference Voltage
Voltage Stable
PIC18F97J94 FAMILY
DS30575A-page 648 2012 Microchip Technology Inc.
FIGURE 31-9: HIGH/LOW-VOLTAGE DETECT CHARACTERISTICS
TABLE 31-23: HIGH/LOW-VOLTAGE DETECT CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
Param
No. Sym Characteristic Min Typ Max Units Conditions
D420 HLVD Voltage on VDD
Transition High-to-Low
HLVDL<3:0> = 0100 2.0 — 2.2 V
HLVDL<3:0> = 0101 2.1 — 2.3 V
HLVDL<3:0> = 0110 2.2 — 2.4 V
HLVDL<3:0> = 0111 2.3 — 2.5 V
HLVDL<3:0> = 1000 2.4 — 2.6 V
HLVDL<3:0> = 1001 2.5 — 2.75 V
HLVDL<3:0> = 1010 2.7 — 2.95 V
HLVDL<3:0> = 1011 2.8 — 3.1 V
HLVDL<3:0> = 1100 3.0 — 3.3 V
HLVDL<3:0> = 1101 3.3 — 3.6 V
HLVDL<3:0> = 1110 3.45 — 3.75 V
VHLVD
HLVDIF
VDD
(HLVDIF set by hardware) (HLVDIF can be
cleared in software)
VHLVD
For VDIRMAG = 1:
For VDIRMAG = 0:VDD
2012 Microchip Technology Inc. DS30575A-page 649
PIC18F97J94 FAMILY
FIGURE 31-10: TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
TABLE 31-24: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
No. Symbol Characteristic Min Max Units Conditions
40 TT0H T0CKI High Pulse Width No prescaler 0.5 TCY + 20 — ns
With prescaler 10 — ns
41 TT0L T0CKI Low Pulse Width No prescaler 0.5 TCY + 20 — ns
With prescaler 10 — ns
42 TT0P T0CKI Period No prescaler TCY + 10 — ns
With prescaler Greater of:
20 ns or
(TCY + 40)/N
—nsN = prescale
value
(1, 2, 4,..., 256)
45 TT1H T1CKI High
Time
Synchronous, no prescaler 0.5 TCY + 20 — ns
Synchronous, with prescaler 10 — ns
Asynchronous 30 — ns
46 TT1L T1CKI Low
Time
Synchronous, no prescaler 0.5 TCY + 5 — ns
Synchronous, with prescaler 10 — ns
Asynchronous 30 — ns
47 TT1P T1CKI Input
Period
Synchronous Greater of:
20 ns or
(TCY + 40)/N
—nsN = prescale
value
(1, 2, 4, 8)
Asynchronous 60 — ns
FT1 T1CKI Oscillator Input Frequency Range DC 50 kHz
48 T
CKE2TMRI Delay from External T1CKI Clock Edge to
Timer Increment
2 TOSC 7 TOSC —
Note: Refer to Figure 31-2 for load conditions.
46
47
45
48
41
42
40
TxCKI
SOSCO/SCLKI
TMR0 or
TMR1
PIC18F97J94 FAMILY
DS30575A-page 650 2012 Microchip Technology Inc.
FIGURE 31-11: CAPTURE/COMPARE/PWM TIMINGS (CCP1, CCP2 MODULES)
TABLE 31-25: CAPTURE/COMPARE/PWM REQUIREMENTS (CCP1, CCP2 MODULES)
Param
No. Symbol Characteristic Min Max Units Conditions
50 TCCL CCPx Input Low
Time
No prescaler 0.5 TCY + 20 — ns
With prescaler 10 — ns
51 TCCH CCPx Input
High Time
No prescaler 0.5 TCY + 20 — ns
With prescaler 10 — ns
52 TCCP CCPx Input Period 3 TCY + 40
N
— ns N = prescale
value (1, 4 or 16)
53 TCCR CCPx Output Fall Time — 25 ns
54 TCCF CCPx Output Fall Time — 25 ns
Note: Refer to Figure 31-2 for load conditions.
CCPx
(Capture Mode)
50 51
52
CCPx
53 54
(Compare or PWM Mode)
2012 Microchip Technology Inc. DS30575A-page 651
PIC18F97J94 FAMILY
FIGURE 31-12: EXAMPLE SPI MASTER MODE TIMING (CKE = 0)
TABLE 31-26: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 0)
Param
No. Symbol Characteristic Min Max Units Conditions
73 TDIV2SCH,
TDIV2SCL
Setup Time of SDIx Data Input to SCKx Edge 20 — ns
73A TB2BLast Clock Edge of Byte 1 to the 1st Clock Edge
of Byte 2
1.5 TCY + 40 — ns
74 T
SCH2DIL,
T
SCL2DIL
Hold Time of SDIx Data Input to SCKx Edge 40 — ns
75 TDOR SDOx Data Output Rise Time — 25 ns
76 TDOF SDOx Data Output Fall Time — 25 ns
78 TSCR SCKx Output Rise Time (Master mode) — 25 ns
79 T
SCF SCKx Output Fall Time (Master mode) — 25 ns
80 T
SCH2DOV,
T
SCL2DOV
SDOx Data Output Valid after SCKx Edge — 50 ns
SCKx
(CKPx = 0)
SCKx
(CKPx = 1)
SDOx
SDIx
73
74
75, 76
78
79
80
79
78
MSb LSb
bit 6 - - - - - - 1
LSb In
bit 6 - - - - 1
Note: Refer to Figure 31-2 for load conditions.
MSb In
PIC18F97J94 FAMILY
DS30575A-page 652 2012 Microchip Technology Inc.
FIGURE 31-13: EXAMPLE SPI MASTER MODE TIMING (CKE = 1)
TABLE 31-27: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 1)
Param.
No. Symbol Characteristic Min Max Units Conditions
73 TDIV2SCH,
TDIV2SCL
Setup Time of SDIx Data Input to SCKx Edge 20 — ns
73A TB2BLast Clock Edge of Byte 1 to the 1st Clock Edge
of Byte 2
1.5 TCY + 40 — ns
74 T
SCH2DIL,
T
SCL2DIL
Hold Time of SDIx Data Input to SCKx Edge 40 — ns
75 TDOR SDOx Data Output Rise Time — 25 ns
76 TDOF SDOx Data Output Fall Time — 25 ns
78 T
SCR SCKx Output Rise Time (Master mode) — 25 ns
79 TSCF SCKx Output Fall Time (Master mode) — 25 ns
80 T
SCH2DOV,
T
SCL2DOV
SDOx Data Output Valid after SCKx Edge — 50 ns
81 TDOV2SCH,
TDOV2SCL
SDOx Data Output Setup to SCKx Edge T
CY —ns
SCKx
(CKPx = 0)
SCKx
(CKPx = 1)
SDOx
SDIx
81
74
75, 76
78
80
MSb
79
73
bit 6 - - - - - - 1
LSb In
bit 6 - - - - 1
LSb
Note: Refer to Figure 31-2 for load conditions.
MSb In
2012 Microchip Technology Inc. DS30575A-page 653
PIC18F97J94 FAMILY
FIGURE 31-14: EXAMPLE SPI SLAVE MODE TIMING (CKE = 0)
TABLE 31-28: EXAMPLE SPI MODE REQUIREMENTS (SLAVE MODE TIMING, CKE = 0)
Param
No. Symbol Characteristic Min Max Units Conditions
70 T
SSL2SCH,
T
SSL2SCL
SSx to SCKx or SCKx Input 3 TCY —ns
70A T
SSL2WB SSx to write to SSPBUF 3 TCY —ns
71 TSCH SCKx Input High Time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
71A Single Byte 40 — ns (Note 1)
72 T
SCL SCKx Input Low Time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
72A Single Byte 40 — ns (Note 1)
73 TDIV2SCH,
TDIV2SCL
Setup Time of SDIx Data Input to SCKx Edge 20 — ns
73A TB2BLast Clock Edge of Byte 1 to the First Clock Edge of Byte 2 1.5 TCY + 40 — ns (Note 2)
74 T
SCH2DIL,
T
SCL2DIL
Hold Time of SDIx Data Input to SCKx Edge 40 — ns
75 TDOR SDOx Data Output Rise Time — 25 ns
76 TDOF SDOx Data Output Fall Time — 25 ns
77 T
SSH2DOZ SSx to SDOx Output High-impedance 10 50 ns
78 TSCR SCKx Output Rise Time (Master mode) — 25 ns
79 TSCF SCKx Output Fall Time (Master mode) — 25 ns
80 T
SCH2DOV,
T
SCL2DOV
SDOx Data Output Valid after SCKx Edge — 50 ns
83 T
SCH2SSH,
T
SCL2SSH
SSx after SCKx Edge 1.5 TCY + 40 — ns
Note 1: Requires the use of Parameter #73A.
2: Only if Parameter #71A and #72A are used.
SSx
SCKx
(CKPx = 0)
SCKx
(CKP = 1)
SDOx
SDIx
70
71 72
73
74
75, 76 77
78
79
80
79
78
MSb LSb
bit 6 - - - - - - 1
bit 6 - - - - 1 LSb In
83
Note: Refer to Figure 31-2 for load conditions.
MSb In
PIC18F97J94 FAMILY
DS30575A-page 654 2012 Microchip Technology Inc.
FIGURE 31-15: EXAMPLE SPI SLAVE MODE TIMING (CKE = 1)
TABLE 31-29: EXAMPLE SPI SLAVE MODE REQUIREMENTS (CKE = 1)
Param
No. Symbol Characteristic Min Max Units Conditions
70 T
SSL2SCH,
T
SSL2SCL
SSx to SCKx or SCKx Input 3 TCY —ns
70A TSSL2WB SSx to Write to SSPBUF 3 TCY —ns
71 TSCH SCKx Input High Time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
71A Single Byte 40 — ns (Note 1)
72 T
SCL SCKx Input Low Time
(Slave mode)
Continuous 1.25 TCY + 30 — ns
72A Single Byte 40 — ns (Note 1)
73A TB2BLast Clock Edge of Byte 1 to the First Clock Edge of Byte 2 1.5 TCY + 40 — ns (Note 2)
74 TSCH2DIL,
T
SCL2DIL
Hold Time of SDIx Data Input to SCKx Edge 40 — ns
75 TDOR SDOx Data Output Rise Time — 25 ns
76 TDOF SDOx Data Output Fall Time — 25 ns
77 T
SSH2DOZ SSx to SDOx Output High-Impedance 10 50 ns
78 T
SCR SCKx Output Rise Time (Master mode) — 25 ns
79 TSCF SCKx Output Fall Time (Master mode) — 25 ns
80 TSCH2DOV,
T
SCL2DOV
SDOx Data Output Valid after SCKx Edge — 50 ns
82 T
SSL2DOV SDOx Data Output Valid after SSx Edge — 50 ns
83 T
SCH2SSH,
T
SCL2SSH
SSx after SCKx Edge 1.5 TCY + 40 — ns
Note 1: Requires the use of Parameter #73A.
2: Only if Parameter #71A and #72A are used.
SSx
SCKx
(CKPx = 0)
SCKx
(CKPx = 1)
SDOx
SDIx
70
71 72
82
74
75, 76
MSb bit 6 - - - - - - 1 LSb
77
bit 6 - - - - 1 LSb In
80
83
Note: Refer to Figure 31-2 for load conditions.
MSb In
2012 Microchip Technology Inc. DS30575A-page 655
PIC18F97J94 FAMILY
FIGURE 31-16: I2C™ BUS START/STOP BITS TIMING
TABLE 31-30: I2C™ BUS START/STOP BITS REQUIREMENTS (SLAVE MODE)
Param.
No. Symbol Characteristic Min Max Units Conditions
90 TSU:STA Start Condition 100 kHz mode 4700 — ns Only relevant for Repeated
Start condition
Setup Time 400 kHz mode 600 —
91 THD:STA Start Condition 100 kHz mode 4000 — ns After this period, the first
clock pulse is generated
Hold Time 400 kHz mode 600 —
92 TSU:STO Stop Condition 100 kHz mode 4700 — ns
Setup Time 400 kHz mode 600 —
93 THD:STO Stop Condition 100 kHz mode 4000 — ns
Hold Time 400 kHz mode 600 —
Note: Refer to Figure 31-2 for load conditions.
91
92
93
SCLx
SDAx
Start
Condition
Stop
Condition
90
PIC18F97J94 FAMILY
DS30575A-page 656 2012 Microchip Technology Inc.
FIGURE 31-17: I2C™ BUS DATA TIMING
TABLE 31-31: I2C™ BUS DATA REQUIREMENTS (SLAVE MODE)
Param.
No. Symbol Characteristic Min Max Units Conditions
100 THIGH Clock High Time 100 kHz mode 4.0 — s
400 kHz mode 0.6 — s
MSSPx module 1.5 TCY —
101 TLOW Clock Low Time 100 kHz mode 4.7 — s
400 kHz mode 1.3 — s
MSSPx module 1.5 TCY —
102 TRSDAx and SCLx Rise Time 100 kHz mode — 1000 ns
400 kHz mode 20 + 0.1 CB300 ns CB is specified to be from
10 to 400 pF
103 TFSDAx and SCLx Fall Time 100 kHz mode — 300 ns
400 kHz mode 20 + 0.1 CB300 ns CB is specified to be from
10 to 400 pF
90 TSU:STA Start Condition Setup Time 100 kHz mode 4.7 — s Only relevant for Repeated
Start condition
400 kHz mode 0.6 — s
91 THD:STA Start Condition Hold Time 100 kHz mode 4.0 — s After this period, the first clock
pulse is generated
400 kHz mode 0.6 — s
106 THD:DAT Data Input Hold Time 100 kHz mode 0 — ns
400 kHz mode 0 0.9 s
107 TSU:DAT Data Input Setup Time 100 kHz mode 250 — ns (Note 2)
400 kHz mode 100 — ns
92 TSU:STO Stop Condition Setup Time 100 kHz mode 4.7 — s
400 kHz mode 0.6 — s
109 TAA Output Valid from Clock 100 kHz mode — 3500 ns (Note 1)
400 kHz mode — — ns
110 TBUF Bus Free Time 100 kHz mode 4.7 — s Time the bus must be free before
a new transmission can start
400 kHz mode 1.3 — s
D102 CBBus Capacitive Loading — 400 pF
Note 1: As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region (min. 300 ns) of
the falling edge of SCLx to avoid unintended generation of Start or Stop conditions.
2: A Fast mode I2C™ bus device can be used in a Standard mode I2C bus system, but the requirement, TSU:DAT 250 ns,
must then be met. This will automatically be the case if the device does not stretch the LOW period of the SCLx signal. If
such a device does stretch the LOW period of the SCLx signal, it must output the next data bit to the SDAx line,
TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according to the Standard mode I2C bus specification), before the SCLx line is
released.
Note: Refer to Figure 31-2 for load conditions.
90
91 92
100
101
103
106 107
109 109
110
102
SCLx
SDAx
In
SDAx
Out
2012 Microchip Technology Inc. DS30575A-page 657
PIC18F97J94 FAMILY
FIGURE 31-18: MSSPx I2C™ BUS START/STOP BITS TIMING WAVEFORMS
TABLE 31-32: MSSPx I2C™ BUS START/STOP BITS REQUIREMENTS
FIGURE 31-19: MSSPx I2C™ BUS DATA TIMING
Param.
No. Symbol Characteristic Min Max Units Conditions
90 TSU:STA Start Condition 100 kHz mode 2(TOSC)(BRG + 1) — ns Only relevant for
Repeated Start
condition
Setup Time 400 kHz mode 2(TOSC)(BRG + 1) —
1 MHz mode(1)2(TOSC)(BRG + 1) —
91 THD:STA Start Condition 100 kHz mode 2(TOSC)(BRG + 1) — ns After this period, the
first clock pulse is
generated
Hold Time 400 kHz mode 2(TOSC)(BRG + 1) —
1 MHz mode(1)2(TOSC)(BRG + 1) —
92 TSU:STO Stop Condition 100 kHz mode 2(TOSC)(BRG + 1) — ns
Setup Time 400 kHz mode 2(TOSC)(BRG + 1) —
1 MHz mode(1)2(TOSC)(BRG + 1) —
93 THD:STO Stop Condition 100 kHz mode 2(TOSC)(BRG + 1) — ns
Hold Time 400 kHz mode 2(TOSC)(BRG + 1) —
1 MHz mode(1)2(TOSC)(BRG + 1) —
Note 1: Maximum pin capacitance = 10 pF for all I2C™ pins.
Note: Refer to Figure 31-2 for load conditions.
91 93
SCLx
SDAx
Start
Condition
Stop
Condition
90 92
Note: Refer to Figure 31-2 for load conditions.
90 91 92
100
101
103
106 107
109 109 110
102
SCLx
SDAx
In
SDAx
Out
PIC18F97J94 FAMILY
DS30575A-page 658 2012 Microchip Technology Inc.
TABLE 31-33: MSSPx I2C™ BUS DATA REQUIREMENTS
Param.
No. Symbol Characteristic Min Max Units Conditions
100 THIGH Clock High
Time
100 kHz mode 2(TOSC)(BRG + 1) — —
400 kHz mode 2(TOSC)(BRG + 1) — —
1 MHz mode(1)2(TOSC)(BRG + 1) — —
101 TLOW Clock Low Time 100 kHz mode 2(TOSC)(BRG + 1) — —
400 kHz mode 2(TOSC)(BRG + 1) — —
1 MHz mode(1)2(TOSC)(BRG + 1) — —
102 TRSDAx and
SCLx Rise
Time
100 kHz mode — 1000 ns CB is specified to be from
10 to 400 pF
400 kHz mode 20 + 0.1 CB300 ns
1 MHz mode(1) — 300 ns
103 TFSDAx and
SCLx Fall Time
100 kHz mode — 300 ns CB is specified to be from
10 to 400 pF
400 kHz mode 20 + 0.1 CB 300 ns
1 MHz mode(1) — 100 ns
90 TSU:STA Start Condition
Setup Time
100 kHz mode 2(TOSC)(BRG + 1) — — Only relevant for Repeated
Start condition
400 kHz mode 2(TOSC)(BRG + 1) — —
1 MHz mode(1) 2(TOSC)(BRG + 1) — —
91 THD:STA Start Condition
Hold Time
100 kHz mode 2(TOSC)(BRG + 1) — — After this period, the first
clock pulse is generated
400 kHz mode 2(TOSC)(BRG + 1) — —
1 MHz mode(1) 2(TOSC)(BRG + 1) — —
106 THD:DAT Data Input
Hold Time
100 kHz mode 0 — —
400 kHz mode 0 0.9 s
1 MHz mode(1) —sns
107 TSU:DAT Data Input
Setup Time
100 kHz mode 250 — ns (Note 2)
400 kHz mode 100 — ns
1 MHz mode(1) ——ns
92 TSU:STO Stop Condition
Setup Time
100 kHz mode 2(TOSC)(BRG + 1) — —
400 kHz mode 2(TOSC)(BRG + 1) — —
1 MHz mode(1) 2(TOSC)(BRG + 1) — —
109 TAA Output Valid
from Clock
100 kHz mode — 3500 ns
400 kHz mode — 1000 ns
1 MHz mode(1) ——ns
110 TBUF Bus Free Time 100 kHz mode 4.7 — s Time the bus must be free
before a new transmission
can start
400 kHz mode 1.3 — s
1 MHz mode(1) ——s
D102 CBBus Capacitive Loading — 400 pF
Note 1: Maximum pin capacitance = 10 pF for all I2C™ pins.
2: A Fast mode I2C bus device can be used in a Standard mode I2C bus system, but Parameter #107 250 ns
must then be met. This will automatically be the case if the device does not stretch the LOW period of the
SCLx signal. If such a device does stretch the LOW period of the SCLx signal, it must output the next data
bit to the SDAx line, Parameter #102 + Parameter #107 = 1000 + 250 = 1250 ns (for 100 kHz mode),
before the SCLx line is released.
2012 Microchip Technology Inc. DS30575A-page 659
PIC18F97J94 FAMILY
FIGURE 31-20: EUSARTx SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
TABLE 31-34: EUSARTx/AUSARTx SYNCHRONOUS TRANSMISSION REQUIREMENTS
FIGURE 31-21: EUSARTx/AUSARTx SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
TABLE 31-35: EUSARTx/AUSARTx SYNCHRONOUS RECEIVE REQUIREMENTS
Param
No. Symbol Characteristic Min Max Units Conditions
120 T
CKH2DTV SYNC XMIT (MASTER and SLAVE)
Clock High to Data Out Valid — 40 ns
121 TCKRF Clock Out Rise Time and Fall Time (Master mode) — 20 ns
122 TDTRF Data Out Rise Time and Fall Time — 20 ns
Param.
No. Symbol Characteristic Min Max Units Conditions
125 TDTV2CKL SYNC RCV (MASTER and SLAVE)
Data Hold before CKx (DTx hold time) 10 — ns
126 TCKL2DTL Data Hold after CKx (DTx hold time) 15 — ns
121 121
120 122
TXx/CKx
RXx/DTx
pin
pin
Note: Refer to Figure 31-2 for load conditions.
125
126
TXx/CKx
RXx/DTx
pin
pin
Note: Refer to Figure 31-2 for load conditions.
PIC18F97J94 FAMILY
DS30575A-page 660 2012 Microchip Technology Inc.
TABLE 31-36: A/D CONVERTER CHARACTERISTICS: PIC18F97J94 (INDUSTRIAL)
Param
No. Sym Characteristic Min Typ Max Units Conditions
A01 NRResolution — — 12 bit VREF 2.0V
A03 EIL Integral Linearity Error — <±1 ±2.0 LSB VDD = 3.0V (VREF 2.0V)
A04 EDL Differential Linearity Error — <±1 +2.0/-1.0 LSB VDD = 3.0V (VREF 2.0V)
A06 EOFF Offset Error — <±1 ±5 LSB VDD = 3.0V (VREF 2.0V)
A07 EGN Gain Error — <±1 ±5 LSB VDD = 3.0V (VREF 2.0V)
A10 — Monotonicity(1)—VSS VAIN VREF
A20 VREF Reference Voltage Range
(VREFH – VREFL)
2—V
DD – VSS V For 12-bit resolution
A21 VREFH Reference Voltage High AVSS + 2.0V — AVDD + 0.3V V For 12-bit resolution
A22 VREFL Reference Voltage Low AVSS – 0.3V — AVDD – 2.0V V For 12-bit resolution
A25 VAIN Analog Input Voltage VREFL —VREFH V
A28 AVDD Analog Supply Voltage VDD – 0.3 — VDD + 0.3 V
A29 AVSS Analog Supply Voltage VSS – 0.3 — VSS + 0.3 V
A30 ZAIN Recommended
Impedance of Analog
Voltage Source
——2.5k
A50 IREF VREF Input Current(2)—
—
—
—
5
150
A
A
During VAIN acquisition.
During A/D conversion cycle.
Note 1: The A/D conversion result never decreases with an increase in the input voltage.
2: VREFH current is from the RA3/AN3/VREF+ pin or VDD, whichever is selected as the VREFH source. VREFL current is from
the RA2/AN2/VREF-/CVREF pin or VSS, whichever is selected as the VREFL source.
2012 Microchip Technology Inc. DS30575A-page 661
PIC18F97J94 FAMILY
FIGURE 31-22: A/D CONVERSION TIMING
TABLE 31-37: A/D CONVERSION REQUIREMENTS
Param
No. Symbol Characteristic Min Max Units Conditions
Sample Start Delay from Setting SAMP 2 3 TAD
130 TAD A/D Clock Period 300 — ns
250 — ns A/D RC mode
131 TCNV Conversion Time
(not including acquisition time)(2)
14 15 TAD
132 TACQ Acquisition Time(3)— 750 ns -40°C to +85°C(5)
135 TSWC Switching Time from Convert Sample — (Note 4)
TDIS Discharge Time 1 — TAD -40°C to +85°C
A/D Stabilization Time (from setting ADON
to setting SAMP)
300 — ns
Note 1: The time of the A/D clock period is dependent on the device frequency and the TAD clock divider.
2: ADRES registers may be read on the following T
CY cycle.
3: The time for the holding capacitor to acquire the “New” input voltage when the voltage changes full scale
after the conversion (VDD to VSS or VSS to VDD). The source impedance (RS) on the input channels is 50.
4: On the following cycle of the device clock.
5: The time for the holding capacitor to acquire the “New” input voltage when the voltage changes full scale
after the conversion (AVDD to AVSS or AVSS to AVDD).
131
130
132
BSF ADCON1L, SAMP
Q4
A/D CLK
A/D DATA
ADRES
ADIF
GO
SAMPLE
OLD_DATA
SAMPLING STOPPED
DONE
NEW_DATA
(Note 2)
11 10 9 2 1 0
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the SLEEP instruction to
be executed.
2: This is a minimal RC delay (typically 100 ns), which also disconnects the holding capacitor from the analog input.
. . . . . .
TCY (Note 1)
PIC18F97J94 FAMILY
DS30575A-page 662 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 663
PIC18F97J94 FAMILY
32.0 PACKAGING INFORMATION
32.1 Package Marking Information
64-Lead QFN (9x9x0.9 mm) Example
PIN 1
XXXXXXXXXXX
XXXXXXXXXXX
XXXXXXXXXXX
YYWWNNN
PIN 1
64-Lead TQFP Example
18F67J94-
I/PT
1210017
3
e
XXXXXXXXXX
XXXXXXXXXX
YYWWNNN
XXXXXXXXXX
80-Lead TQFP Example
PIC18F87J94-
I/PT
1210017
3
e
XXXXXXXXXXXX
XXXXXXXXXXXX
YYWWNNN
100-Lead TQFP (12x12x1 mm)
XXXXXXXXXXXX
XXXXXXXXXXXX
YYWWNNN
Example
PIC18F97J94-
I/PT
1210017
3
e
PIC18F97J94 FAMILY
DS30575A-page 664 2012 Microchip Technology Inc.
100-Lead TQFP (14x14x1 mm) Example
PIC18F97J94-
I/PF
1210017
Legend: XX...X Customer-specific information
Y Year code (last digit of calendar year)
YY Year code (last 2 digits of calendar year)
WW Week code (week of January 1 is week ‘01’)
NNN Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
*This package is Pb-free. The Pb-free JEDEC designator ( )
can be found on the outer packaging for this package.
Note: In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
3
e
3
e
3
e
XXXXXXXXXXXX
XXXXXXXXXXXX
YYWWNNN
2012 Microchip Technology Inc. DS30575A-page 665
PIC18F97J94 FAMILY
32.2 Package Details
The following sections give the technical details of the packages.
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
PIC18F97J94 FAMILY
DS30575A-page 666 2012 Microchip Technology Inc.
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
2012 Microchip Technology Inc. DS30575A-page 667
PIC18F97J94 FAMILY
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
PIC18F97J94 FAMILY
DS30575A-page 668 2012 Microchip Technology Inc.
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Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
PIC18F97J94 FAMILY
DS30575A-page 670 2012 Microchip Technology Inc.
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PIC18F97J94 FAMILY
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
PIC18F97J94 FAMILY
DS30575A-page 672 2012 Microchip Technology Inc.
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2012 Microchip Technology Inc. DS30575A-page 673
PIC18F97J94 FAMILY
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
PIC18F97J94 FAMILY
DS30575A-page 674 2012 Microchip Technology Inc.
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2012 Microchip Technology Inc. DS30575A-page 675
PIC18F97J94 FAMILY
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
PIC18F97J94 FAMILY
DS30575A-page 676 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 677
PIC18F97J94 FAMILY
APPENDIX A: REVISION HISTORY
Revision A (October 2012)
Original data sheet for PIC18F97J94 family devices.
PIC18F97J94 FAMILY
DS30575A-page 678 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 679
PIC18F97J94 FAMILY
INDEX
Numerics
12-Bit A/D Converter with Threshold Scan ...................... 435
A
A/D
A/D Module State Machine Module ......................... 457
Conversion Requirements ....................................... 661
Converter Characteristics ........................................ 660
Registers .................................................................. 437
Absolute Maximum Ratings ............................................. 629
AC (Timing) Characteristics ............................................. 640
Load Conditions for Device Timing Specifications ... 641
Parameter Symbology ............................................. 640
Temperature and Voltage Specifications ................. 641
Timing Conditions .................................................... 641
ACKSTAT ........................................................................ 401
ACKSTAT Status Flag ..................................................... 401
Active Clock Tuning (ACT) Module .................................... 59
ADDFSR .......................................................................... 618
ADDLW ............................................................................ 581
ADDULNK ........................................................................ 618
ADDWF ............................................................................ 581
ADDWFC ......................................................................... 582
ANDLW ............................................................................ 582
ANDWF ............................................................................ 583
Assembler
MPASM Assembler .................................................. 626
Auto-Wake-up on Sync Break Character ......................... 424
B
Baud Rate Generator ....................................................... 397
BC .................................................................................... 583
BCF .................................................................................. 584
BF .................................................................................... 401
BF Status Flag ................................................................. 401
Block Diagrams
100-Pin Devices ......................................................... 16
12-Bit A/D Converter ................................................ 436
16-Bit Byte Select Mode .......................................... 159
16-Bit Byte Write Mode ............................................ 157
16-Bit Word Write Mode ........................................... 158
64-Pin Devices ........................................................... 14
80-Pin Devices ........................................................... 15
8-Bit Multiplexed Mode ............................................ 161
96 MHz PLL ............................................................... 54
Basic Oscillator .......................................................... 53
Baud Rate Generator ............................................... 397
Bus Power Only ....................................................... 546
Capture Mode Operation ................................. 321, 345
Comparator Analog Input Model .............................. 492
Comparator Configurations ...................................... 494
Comparator Module ................................................. 489
Comparator Voltage Reference ............................... 498
Comparator Voltage Reference Output Buffer ......... 499
Compare Mode Operation ............................... 322, 347
Crystal or Ceramic Resonator Operation
(MS or HS) ......................................................... 49
CTMU ....................................................................... 507
CTMU Current Source Calibration Circuit ................ 514
CTMU Temperature Measurement Circuit ............... 522
CTMU Typical Connections and Internal
Configuration for Time Measurement .............. 521
Data Signal Modulator ............................................. 236
Dual Power with Self-Power Dominance ................. 546
Enhanced PWM Mode ............................................. 323
EUSARTx Receive .................................................. 423
EUSARTx Transmit ................................................. 421
External Clock Input (CLKOEN = 0) .......................... 52
External Clock Input (CLKOEN = 1) .......................... 52
External Power-on Reset Circuit
(Slow VDD Power-up) ........................................ 92
Fail-Safe Clock Monitor (FSCM) .............................. 571
Full-Bridge Application Example .............................. 327
Generic I/O Port Operation ...................................... 197
Half-Bridge Applications .......................................... 333
High/Low-Voltage Detect with External Input .......... 502
Interrupt Logic .......................................................... 169
LCD Clock Generation ............................................. 251
LCD Controller ......................................................... 245
MSSP (SPI Mode) ................................................... 352
MSSPx (I2C Master Mode) ...................................... 395
MSSPx (I2C Mode) .................................................. 372
Multiplexing of Remappable Output for RPn ........... 230
On-Chip Reset Circuit ................................................ 85
PIC18F General System Clock .................................. 37
Port Shared with PPS Peripherals Structure ........... 225
PORTD and PORTE (Parallel Slave Port) ............... 221
PWM Operation (Simplified) .................................... 348
Reads from Flash Program Memory ....................... 147
Remappable Input for U1RX ................................... 226
RTCC ....................................................................... 297
RTCC Clock Source Multiplexing ............................ 311
Self Tuning ................................................................ 60
Self-Power Only ....................................................... 546
Simplified Steering ................................................... 336
Single Comparator ................................................... 492
SPI Master/Slave Connection .................................. 357
Table Read Operation ............................................. 143
Table Write Operation ............................................. 144
Table Writes to Flash Program Memory .................. 149
Timer0 in 16-Bit Mode ............................................. 282
Timer0 in 8-Bit Mode ............................................... 282
Timer1/3/5 ............................................................... 287
Timer2/4/6/8 ............................................................ 295
USB Buffer Descriptor ............................................. 534
USB External Circuitry ............................................. 530
USB Interrupt Logic ................................................. 540
USB Layers ............................................................. 550
USB Peripheral and Options ................................... 525
Using Open-Drain Output (USART) ........................ 199
USTAT FIFO ............................................................ 531
VBAT POWER TOPOLOGY ............................................. 75
Watchdog Timer ...................................................... 568
BN .................................................................................... 584
BNC ................................................................................. 585
BNN ................................................................................. 585
BNOV .............................................................................. 586
BNZ ................................................................................. 586
BOR. See Brown-out Reset.
BOV ................................................................................. 589
BRA ................................................................................. 587
Break Character (12-Bit) Transmit and Receive .............. 426
BRG. See Baud Rate Generator.
BSF .................................................................................. 587
BTFSC ............................................................................. 588
BTFSS ............................................................................. 588
PIC18F97J94 FAMILY
DS30575A-page 680 2012 Microchip Technology Inc.
BTG ..................................................................................589
BZ .....................................................................................590
C
C Compilers
MPLAB C18 .............................................................626
CALL ................................................................................ 590
CALLW ............................................................................. 619
Capture (CCP Module) ..................................................... 344
CCPR4H:CCPR4L Registers ................................... 344
Pin Configuration ..................................................... 344
Prescaler ..................................................................345
Software Interrupt ....................................................345
Timer1/3/5/7 Mode Selection ................................... 344
Capture (ECCP Module) .................................................. 321
CCPRxH:CCPRxL Registers ................................... 321
ECCP Pin Configuration .......................................... 321
Prescaler ..................................................................321
Software Interrupt ....................................................321
Timer1/2/3/4/5/6/8 Mode Selection ..........................321
Capture/Compare/PWM (CCP) ........................................ 339
Capture Mode. See Capture.
CCP Mode and Timer Resources ............................ 343
CCP6/7/8/9 Pin Assignment .................................... 344
CCPRxH Register .................................................... 343
CCPRxL Register ..................................................... 343
Compare Mode. See Compare.
Configuration ............................................................ 343
Open-Drain Output Option ....................................... 344
Charge Time Measurement Unit (CTMU) ........................ 507
Calibrating the Module ............................................. 513
Effects of a Reset ..................................................... 523
Measuring Capacitance ........................................... 519
Measuring Time ....................................................... 521
Module Initialization ................................................. 513
Operation ................................................................. 512
During Sleep, Idle Modes ................................. 523
Temperature Measurement .....................................522
Clock Switching
Considerations ...........................................................59
Clock Switching Operation .................................................57
Abandoning ................................................................ 62
Enabling ..................................................................... 58
Entering Sleep Mode ................................................. 62
Sequence ................................................................... 58
CLRF ................................................................................ 591
CLRWDT .......................................................................... 591
Code Examples
16 x 16 Signed Multiply Routine .............................. 166
16 x 16 Unsigned Multiply Routine .......................... 166
512-Byte SPI Master Mode INIT, Transfer ............... 370
8 x 8 Signed Multiply Routine .................................. 165
8 x 8 Unsigned Multiply Routine .............................. 165
Changing Between Capture Prescalers ........... 321, 345
Clearing ACTVIF Bit (UIR) ....................................... 542
Computed GOTO Using an Offset Value ................. 117
Converting 1 Channel, Manual Sample and
Conversion Start .............................................. 462
Converting 1 Channel, Manual Sample Start, TAD
Based Conversion Start ...................................463
CTMU Capacitance Calibration Routine .................. 518
CTMU Routine for Capacitive Touch Switch ............ 520
CTMU Routine for Temperature Measurement
Using Internal Diode ........................................522
Current Calibration Routine .....................................516
Erasing a Flash Program Memory Row ................... 148
Fast Register Stack ................................................. 117
How to Clear RAM (Bank 1) Using Indirect
Addressing ....................................................... 136
Initializing PORTA .................................................... 201
Initializing PORTB .................................................... 203
Initializing PORTC ................................................... 205
Initializing PORTD ................................................... 207
Initializing PORTE .................................................... 209
Initializing PORTF .................................................... 211
Initializing PORTG ................................................... 213
Initializing PORTH ................................................... 215
Initializing PORTJ .................................................... 217
Initializing PORTK .................................................... 219
Initializing PORTL .................................................... 220
Loading the SSP1BUF (SSP1SR) Register ............. 356
Reading a Flash Program Memory Word ................ 147
Saving STATUS, WREG and BSR Registers in
RAM ................................................................. 195
Setting the RTCWREN Bit ....................................... 312
Setup for CTMU Calibration Routines ..................... 515
Single-Word Write to Flash Memory ........................ 151
SLEEP Assembly Syntax ........................................... 67
Writing to Flash Program Memory ........................... 150
Code Protection ............................................................... 553
COMF .............................................................................. 592
Comparator ...................................................................... 489
Analog Input Connection Considerations ................ 492
Configuration ........................................................... 493
Control ..................................................................... 493
Effects of a Reset .................................................... 496
Enable and Input Selection ...................................... 493
Enable and Output Selection ................................... 493
Interrupts ................................................................. 495
Operation ................................................................. 492
Operation During Sleep ........................................... 496
Response Time ........................................................ 492
Comparator Specifications ............................................... 638
Comparator Voltage Reference ....................................... 497
Accuracy and Error .................................................. 499
Configuring .............................................................. 497
Connection Considerations ...................................... 499
Effects of a Reset .................................................... 499
Operation During Sleep ........................................... 499
Comparator Voltage Reference Specifications ................ 638
Compare (CCP Module) .................................................. 346
CCP Pin Configuration ............................................. 346
CCPR4 Register ...................................................... 346
Software Interrupt .................................................... 346
Special Event Trigger .............................................. 346
Timer1/3/5 Mode Selection ...................................... 346
Compare (ECCP Module) ................................................ 322
CCPRx Register ...................................................... 322
Pin Configuration ..................................................... 322
Software Interrupt .................................................... 322
Special Event Trigger ...................................... 293, 322
Timer1/2/3/4/5/6/8 Mode Selection .......................... 322
Computed GOTO ............................................................. 117
Configuration Bits ............................................................ 553
Device IDs, Summary .............................................. 554
Core Features ...................................................................... 9
Easy Migration ........................................................... 10
Extended Instruction Set ........................................... 10
External Memory Bus (EMB) ..................................... 10
Memory Options ........................................................ 10
Universal Serial Bus (USB) ............................... 10
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Oscillator Options and Features .................................. 9
CPFSEQ .......................................................................... 592
CPFSGT .......................................................................... 593
CPFSLT ........................................................................... 593
Customer Change Notification Service ............................ 691
Customer Notification Service .......................................... 691
Customer Support ............................................................ 691
D
Data Addressing Modes ................................................... 136
Comparing Addressing Modes with the
Extended Instruction Set Enabled ................... 140
Direct ........................................................................ 136
Indexed Literal Offset ............................................... 139
BSR ................................................................. 141
Instructions Affected ........................................ 139
Mapping Access Bank ..................................... 141
Indirect ..................................................................... 136
Inherent and Literal .................................................. 136
Data Memory ................................................................... 120
Access Bank ............................................................ 122
Bank Select Register (BSR) ..................................... 120
Extended Instruction Set .......................................... 139
General Purpose Registers ...................................... 122
Memory Maps
PIC18F97J94 Devices ..................................... 121
Special Function Registers (SFRs) .......................... 123
Data Signal Modulator (DSM) .......................................... 235
Carrier Signal Sources ............................................. 237
Carrier Source
Pin Disable ....................................................... 240
Polarity Select .................................................. 240
Carrier Synchronization ........................................... 237
Effects of a Reset ..................................................... 240
Modulated Output Polarity ....................................... 240
Modulator Signal Sources ........................................ 237
Modulator Source Pin Disable ................................. 240
Operation ................................................................. 237
Operation in Sleep Mode ......................................... 240
Programmable Modulator Data ................................ 240
Slew Rate Control .................................................... 240
DAW ................................................................................. 594
DC Characteristics
CTMU Current Source Specifications ...................... 637
Power-Down and Supply Current ............................ 632
Supply Voltage ......................................................... 631
DCFSNZ .......................................................................... 595
DECF ............................................................................... 594
DECFSZ ........................................................................... 595
Deep Sleep Brown-out Reset (DSBOR) ............................ 72
Development Support ...................................................... 625
Device Overview .................................................................. 9
Features (100-Pin Devices) ....................................... 13
Features (64-Pin Devices) ......................................... 12
Features (80-Pin Devices) ......................................... 12
Device Reset Timers
Oscillator Start-up Timer (OST) ................................. 95
PLL Lock Time-out ..................................................... 95
Power-up Timer (PWRT) ........................................... 95
Direct Addressing ............................................................. 137
DSGPRx Registers
Saving Context Data .................................................. 76
E
Effect on Standard PIC18 Instructions ............................. 622
Electrical Characteristics .................................................. 629
Enhanced Capture/Compare/PWM (ECCP) .................... 317
Capture Mode. See Capture.
Compare Mode. See Compare.
Enhanced PWM Mode ............................................. 323
Auto-Restart .................................................... 332
Auto-Shutdown ................................................ 330
Direction Change in Full-Bridge Output Mode . 329
Full-Bridge Application ..................................... 327
Full-Bridge Mode ............................................. 327
Half-Bridge Application .................................... 326
Half-Bridge Application Example ..................... 333
Half-Bridge Mode ............................................. 326
Output Relationships (Active-High) ................. 324
Output Relationships (Active-Low) .................. 325
Programmable Dead-Band Delay .................... 333
Shoot-Through Current .................................... 333
Start-up Considerations ................................... 330
Outputs and Configuration ....................................... 320
Timer Resources ..................................................... 320
Enhanced Universal Synchronous Asynchronous Receiver
Transmitter (EUSART). See EUSART.
Equations
16 x 16 Signed Multiplication Algorithm ................... 166
16 x 16 Unsigned Multiplication Algorithm ............... 166
Bytes Transmitted for a Given DMABC ................... 367
Calculating USB Transceiver Current ...................... 548
Estimating USB Transceiver Current Consumption 547
LCD Static, Dynamic Current .................................. 263
PWM Duty Cycle (in Time) ...................................... 349
PWM Period Calculation .......................................... 348
PWM Resolution ...................................................... 349
Errata ................................................................................... 7
EUSART
Asynchronous Mode ................................................ 421
12-Bit Break Transmit and Receive ................. 426
Auto-Wake-up on Sync Break ......................... 424
Receiver .......................................................... 423
Setting Up 9-Bit Mode with Address Detect .... 423
Transmitter ...................................................... 421
Baud Rate Generator
Operation in Power-Managed Mode ................ 416
Baud Rate Generator (BRG) ................................... 416
Auto-Baud Rate Detect .................................... 419
Baud Rate Error, Calculating ........................... 416
Baud Rates, Asynchronous Modes ................. 417
High Baud Rate Select (BRGH Bit) ................. 416
Sampling ......................................................... 416
Infrared Support ....................................................... 431
Built-in IrDA Encoder, Decoder ....................... 432
External, IrDA Clock Output ............................ 431
Synchronous Master Mode ...................................... 427
Reception ........................................................ 429
Transmission ................................................... 427
Synchronous Slave Mode ........................................ 430
Reception ........................................................ 430
Transmission ................................................... 430
Extended Instruction Set
ADDFSR .................................................................. 618
ADDULNK ............................................................... 618
CALLW .................................................................... 619
MOVSF .................................................................... 619
MOVSS .................................................................... 620
PUSHL ..................................................................... 620
SUBFSR .................................................................. 621
SUBULNK ................................................................ 621
PIC18F97J94 FAMILY
DS30575A-page 682 2012 Microchip Technology Inc.
External Clock Input ........................................................... 52
External Memory Bus ....................................................... 153
16-Bit Byte Select Mode ..........................................159
16-Bit Byte Write Mode ............................................ 157
16-Bit Data Width Modes ......................................... 156
16-Bit Mode Timing .................................................. 160
16-Bit Word Write Mode ........................................... 158
8-Bit Data Width Mode ............................................. 161
8-Bit Mode Timing .................................................... 162
Address and Data Lines for Different Address
and Data Widths (table) ................................... 155
Address and Data Width .......................................... 155
Address Shifting ....................................................... 155
Control .....................................................................154
I/O Port Functions .................................................... 153
Operation in Power-Managed Modes ...................... 163
Program Memory Modes ......................................... 156
Extended Microcontroller ................................. 156
Microcontroller ................................................. 156
Wait States ............................................................... 156
Weak Pull-ups on Port Pins .....................................156
F
Fail-Safe Clock Monitor ............................................ 553, 571
Exiting Operation .....................................................571
Interrupts in Power-Managed Modes ....................... 572
POR or Wake from Sleep ........................................572
WDT During Oscillator Failure ................................. 571
Fail-Safe Clock Monitor (FSCM) ........................................57
and WDT .................................................................... 57
Delay ..........................................................................57
Slow Oscillator Start-up ............................................. 57
Family Member Details ......................................................11
Fast Register Stack .......................................................... 117
Firmware Instructions ....................................................... 575
Flash Program Memory .................................................... 143
Control Registers ..................................................... 144
EECON1 and EECON2 ................................... 144
TABLAT (Table Latch) ..................................... 146
TBLPTR (Table Pointer) ..................................146
Operations with TBLRD, TBLWT ............. 146
Erase Sequence ...................................................... 148
Erasing ..................................................................... 148
Operation During Code-Protect ............................... 152
Reading .................................................................... 147
Table Pointer Boundaries ........................................ 146
Based on Operation ......................................... 146
Table Reads, Table Writes ...................................... 143
Write Sequence ....................................................... 149
Writing ...................................................................... 149
Unexpected Termination .................................. 152
Write Sequence ............................................... 151
Write Verify ......................................................152
FSCM. See Fail-Safe Clock Monitor.
G
Getting Started Guidelines .................................................31
GOTO ...............................................................................596
H
Hardware Multiplier .......................................................... 165
8 x 8 Multiplication Algorithms .................................165
Operation ................................................................. 165
Performance Comparison (table) .............................165
High/Low-Voltage Detect .................................................501
Applications .............................................................. 505
Current Consumption ............................................... 503
Effects of a Reset .................................................... 505
Operation ................................................................. 502
During Sleep .................................................... 505
Setup ....................................................................... 503
Start-up Time ........................................................... 503
Typical Application ................................................... 505
HLVD. See High/Low-Voltage Detect. ............................. 501
I
I/O Ports ........................................................................... 197
Open-Drain Outputs ................................................. 199
Output Pin Drive ...................................................... 197
Pin Capabilities ........................................................ 197
PPS-Lite .................................................................. 224
Pull-up Configuration ............................................... 197
Virtual PORT ............................................................ 224
I2C Mode (MSSP)
Acknowledge Sequence Timing .............................. 404
Baud Rate Generator .............................................. 397
Bus Collision
During a Repeated Start Condition .................. 408
During a Stop Condition .................................. 409
Clock Arbitration ...................................................... 398
Clock Stretching ....................................................... 390
10-Bit Slave Receive Mode (SEN = 1) ............ 390
10-Bit Slave Transmit Mode ............................ 390
7-Bit Slave Receive Mode (SEN = 1) .............. 390
7-Bit Slave Transmit Mode .............................. 390
Clock Synchronization and the CKP bit ................... 391
Effects of a Reset .................................................... 405
General Call Address Support ................................. 394
I2C Clock Rate w/BRG ............................................. 397
Master Mode ............................................................ 395
Operation ......................................................... 396
Reception ........................................................ 401
Repeated Start Condition Timing .................... 400
Start Condition Timing ..................................... 399
Transmission ................................................... 401
Multi-Master Communication, Bus Collision
and Arbitration ................................................. 405
Multi-Master Mode ................................................... 405
Operation ................................................................. 380
Read/Write Bit Information (R/W Bit) ............... 380, 383
Registers ................................................................. 372
Serial Clock (RC3/SCKx/SCLx) ............................... 383
Slave Mode .............................................................. 380
Address Masking Modes
5-Bit ......................................................... 381
7-Bit ......................................................... 382
Addressing ....................................................... 380
Reception ........................................................ 383
Transmission ................................................... 383
Sleep Operation ....................................................... 405
Stop Condition Timing ............................................. 404
ID Locations ..................................................................... 553
INCF ................................................................................ 596
INCFSZ ............................................................................ 597
In-Circuit Debugger .......................................................... 573
In-Circuit Serial Programming (ICSP) ...................... 553, 573
Indexed Literal Offset Addressing
and Standard PIC18 Instructions ............................. 622
Indexed Literal Offset Mode ............................................. 622
Indirect Addressing .......................................................... 137
INFSNZ ............................................................................ 597
Initialization Conditions for All Registers .................... 97–112
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Instruction Cycle .............................................................. 118
Clocking Scheme ..................................................... 118
Flow/Pipelining ......................................................... 118
Instruction Set .................................................................. 575
ADDLW .................................................................... 581
ADDWF .................................................................... 581
ADDWF (Indexed Literal Offset Mode) .................... 623
ADDWFC ................................................................. 582
ANDLW .................................................................... 582
ANDWF .................................................................... 583
BC ............................................................................ 583
BCF .......................................................................... 584
BN ............................................................................ 584
BNC ......................................................................... 585
BNN ......................................................................... 585
BNOV ....................................................................... 586
BNZ .......................................................................... 586
BOV ......................................................................... 589
BRA .......................................................................... 587
BSF .......................................................................... 587
BSF (Indexed Literal Offset Mode) .......................... 623
BTFSC ..................................................................... 588
BTFSS ..................................................................... 588
BTG .......................................................................... 589
BZ ............................................................................ 590
CALL ........................................................................ 590
CLRF ........................................................................ 591
CLRWDT .................................................................. 591
COMF ...................................................................... 592
CPFSEQ .................................................................. 592
CPFSGT .................................................................. 593
CPFSLT ................................................................... 593
DAW ......................................................................... 594
DCFSNZ .................................................................. 595
DECF ....................................................................... 594
DECFSZ ................................................................... 595
Extended Instructions .............................................. 617
Considerations when Enabling ........................ 622
Syntax .............................................................. 617
Use with MPLAB IDE Tools ............................. 624
General Format ........................................................ 577
GOTO ...................................................................... 596
INCF ......................................................................... 596
INCFSZ .................................................................... 597
INFSNZ .................................................................... 597
IORLW ..................................................................... 598
IORWF ..................................................................... 598
LFSR ........................................................................ 599
MOVF ....................................................................... 599
MOVFF .................................................................... 600
MOVLB .................................................................... 600
MOVLW ................................................................... 601
MOVWF ................................................................... 601
MULLW .................................................................... 602
MULWF .................................................................... 602
NEGF ....................................................................... 603
NOP ......................................................................... 603
Opcode Field Descriptions ....................................... 576
POP ......................................................................... 604
PUSH ....................................................................... 604
RCALL ..................................................................... 605
RESET ..................................................................... 605
RETFIE .................................................................... 606
RETLW .................................................................... 606
RETURN .................................................................. 607
RLCF ....................................................................... 607
RLNCF ..................................................................... 608
RRCF ....................................................................... 608
RRNCF .................................................................... 609
SETF ....................................................................... 609
SETF (Indexed Literal Offset Mode) ........................ 623
SLEEP ..................................................................... 610
Standard Instructions ............................................... 575
SUBFWB ................................................................. 610
SUBLW .................................................................... 611
SUBWF .................................................................... 611
SUBWFB ................................................................. 612
SWAPF .................................................................... 612
TBLRD ..................................................................... 613
TBLWT .................................................................... 614
TSTFSZ ................................................................... 615
XORLW ................................................................... 615
XORWF ................................................................... 616
Inter-Integrated Circuit. See I2C.
Internal Fast RC Oscillator (FRC) ...................................... 56
Enabling ..................................................................... 56
Postscaler Mode (FRCDIV) ....................................... 56
with PLL Mode (FRCPLL) .......................................... 56
Internal Low-Power RC Oscillator (LPRC) ......................... 57
Enabling ..................................................................... 57
Internal RC Oscillator
Use with WDT .......................................................... 568
Internal Voltage Regulator Specifications ........................ 638
Internet Address .............................................................. 691
Interrupt Sources ............................................................. 553
Capture Complete (CCP) ........................................ 345
Capture Complete (ECCP) ...................................... 321
Compare Complete (CCP) ...................................... 346
Compare Complete (ECCP) .................................... 322
TMR0 Overflow ........................................................ 283
TMR2 to PR2 Match (PWM) .................................... 348
TMRx Overflow ................................................ 284, 293
Interrupts ......................................................................... 167
During, Context Saving ............................................ 195
Edge-Selectable Interrupt-on-Change ..................... 193
INTx Pin ................................................................... 193
TMR0 ....................................................................... 193
IORLW ............................................................................. 598
IORWF ............................................................................. 598
L
LCD
Bias Configurations ................................................. 259
Bias Types ............................................................... 252
Charge Pump Design Considerations ..................... 263
Clock Source Selection ........................................... 251
Configuring .............................................................. 279
Frame Frequency .................................................... 264
Internal Resistor Biasing .......................................... 252
Interrupts ................................................................. 278
Multiplex Types ........................................................ 264
Operation During Sleep ........................................... 279
Pixel Control ............................................................ 264
Segment Enables .................................................... 264
Segment Pins Configuration .................................... 249
Waveform Generation ............................................. 265
LCD Controller ........................................................... 10, 245
LFSR ............................................................................... 599
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DS30575A-page 684 2012 Microchip Technology Inc.
M
Master Synchronous Serial Port (MSSP). See MSSP.
Memory Organization ....................................................... 113
Data Memory ...........................................................120
Program Memory Maps ...........................................113
Memory Programming Requirements ..............................637
Microchip Internet Web Site .............................................691
MOVF ............................................................................... 599
MOVFF .............................................................................600
MOVLB .............................................................................600
MOVLW ............................................................................ 601
MOVSF ............................................................................ 619
MOVSS ............................................................................ 620
MOVWF ........................................................................... 601
MPLAB ASM30 Assembler, Linker, Librarian .................. 626
MPLAB Integrated Development Environment Software . 625
MPLAB PM3 Device Programmer .................................... 628
MPLAB REAL ICE In-Circuit Emulator System ................ 627
MPLINK Object Linker/MPLIB Object Librarian ............... 626
MSSP
ACK Pulse ........................................................ 380, 383
I2C Mode. See I2C Mode.
Module Overview ..................................................... 351
SPI Master/Slave Connection .................................. 357
TMRx Output for Clock Shift ....................................295
MULLW ............................................................................602
MULWF ............................................................................ 602
N
NEGF ............................................................................... 603
NOP .................................................................................603
O
Oscillator
Clock Switching Mode Configuration Bits .................. 40
Configuration .............................................................. 39
Control Registers ....................................................... 40
CPU Clocking Scheme ..............................................38
OSC1, OSC2 Pin Functions in Non-Crystal Modes ... 40
Oscillator Selection .......................................................... 553
Oscillator, Timer1/3/5 ....................................................... 284
P
P1A/P1B/P1C/P1D.See Enhanced Capture/Compare/
PWM (ECCP). .......................................................... 323
Packaging ........................................................................663
Details ......................................................................665
Marking ....................................................................664
Parallel Slave Port (PSP) .................................................221
PORTD ....................................................................221
Peripheral Power Control ................................................... 79
Disabling Modules ...................................................... 79
Module
Disable Bit (XXMD) ............................................79
Module Enable Bit (XXXEN) ...................................... 79
Phase Lock Loop (PLL) ...................................................... 52
Lock Status ................................................................ 55
Pinout I/O Descriptions ................................................ 17–29
POP .................................................................................. 604
POR. See Power-on Reset.
PORTA
LATA Register ..........................................................201
PORTA Register ...................................................... 201
TRISA Register ........................................................ 201
PORTB
LATB Register ......................................................... 203
PORTB Register ...................................................... 203
TRISB Register ........................................................ 203
PORTC
LATC Register ......................................................... 205
PORTC Register ...................................................... 205
RC3/SCKx/SCLx Pin ............................................... 383
TRISC Register ........................................................ 205
PORTD
LATD Register ......................................................... 207
PORTD Register ...................................................... 207
TRISD Register ........................................................ 207
PORTE
LATE Register ......................................................... 209
PORTE Register ...................................................... 209
RE0/AD8/LCDBIAS1/RP28/RD Pin ......................... 221
RE1/AD9/LCDBIAS2/RP29/WR Pin ........................ 221
RE2/AD10/LCDBIAS3/RP30//CS Pin ...................... 221
TRISE Register ........................................................ 209
PORTF
LATF Register .......................................................... 211
PORTF Register ...................................................... 211
TRISF Register ........................................................ 211
PORTG
LATG Register ......................................................... 213
PORTG Register ...................................................... 213
TRISG Register ....................................................... 213
PORTH
LATH Register ......................................................... 215
PORTH Register ...................................................... 215
TRISH Register ........................................................ 215
PORTJ
LATJ Register .......................................................... 217
PORTJ Register ....................................................... 217
TRISJ Register ........................................................ 217
PORTK
LATK Register ......................................................... 219
PORTK Register ...................................................... 219
TRISK Register ........................................................ 219
PORTL
LATL Register .......................................................... 220
PORTL Register ...................................................... 220
TRISL Register ........................................................ 220
Power-Managed Modes
and EUSART Operation .......................................... 416
and PWM Operation ................................................ 337
and SPI Operation ................................................... 361
Power-Saving Modes ......................................................... 65
Clock Source Considerations .................................... 69
Instruction-Based ....................................................... 67
Summary of Features ................................................ 66
Vbat ........................................................................... 75
Wake-up ............................................................ 76
VbatI/O Pins .............................................................. 76
Prescaler, Timer0 ............................................................ 283
Prescaler, Timer2 ............................................................ 349
Primary Oscillator (POSC) ................................................. 49
Crystal Oscillators, Ceramic Resonators ................... 50
Operating Modes ....................................................... 49
Selecting .................................................................... 50
Program Counter ............................................................. 115
PCL, PCH and PCU Registers ................................ 115
PCLATH and PCLATU Registers ............................ 115
Program Memory
Code Protection ....................................................... 573
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Extended Instruction Set .......................................... 138
Hard Memory Vectors .............................................. 114
Instructions ............................................................... 119
Two-Word ........................................................ 119
Interrupt Vector ........................................................ 114
Look-up Tables ........................................................ 117
Organization ............................................................. 114
Reset Vector ............................................................ 114
Programming, Device Instructions ................................... 575
PSP.See Parallel Slave Port.
Pulse Steering .................................................................. 334
Pulse-Width Modulation. See PWM (CCP Module).
PUSH ............................................................................... 604
PUSH and POP Instructions ............................................ 116
PUSHL ............................................................................. 620
PWM (CCP Module)
Duty Cycle ................................................................ 349
Example Frequencies/Resolutions .......................... 349
Period ....................................................................... 348
Setup for PWM Operation ........................................ 349
TMR2 to PR2 Match ................................................ 348
PWM (ECCP Module)
Effects of a Reset ..................................................... 337
Operation in Power-Managed Modes ...................... 337
Operation with Fail-Safe Clock Monitor ................... 337
Pulse Steering Mode ................................................ 334
Steering Synchronization ......................................... 336
PWM Mode. See Enhanced Capture/Compare/PWM ..... 323
Q
Q Clock ............................................................................ 349
R
RAM. See Data Memory.
RCALL ............................................................................. 605
RCONx Bit Operation on Resets and Wake-ups ............... 96
Reader Response ............................................................ 692
Real-Time Clock and Calendar (RTCC) ........................... 297
Registers .................................................................. 298
Reference Clock Output ..................................................... 45
Applications ................................................................ 62
Enable Signal ............................................................. 63
Operation in Sleep ............................................... 45, 63
REFO1, REFO2 ......................................................... 62
Source .................................................................. 45, 62
Synchronization ................................................... 45, 63
Register File ..................................................................... 122
Register File Summary ............................................ 124–135
Registers
ACTCON (Active Clock Tuning Control) .................... 61
ADCHS0H (A/D Sample Select 0 High) ................... 448
ADCHS0L (A/D Sample Select 0 Low) .................... 449
ADCON1H (A/D Control 1 High) .............................. 441
ADCON1L (A/D Control 1 Low) ............................... 442
ADCON2H (A/D Control 2 High) .............................. 443
ADCON2L (A/D Control 2 Low) ............................... 444
ADCON3H (A/D Control 3 High) .............................. 445
ADCON3L (A/D Control 3 Low) ............................... 445
ADCON5H
(A/D Control 5 High) ........................................ 446
ADCON5L (A/D Control 5 Low) ............................... 447
ADCSS0H (A/D Input Scan Select 0 High) .............. 453
ADCSS0L (A/D Input Scan Select 0 Low) ............... 453
ADCSS1H (A/D Input Scan Select 1 High) .............. 452
ADCSS1L (A/D Input Scan Select 1 Low) ............... 452
ADCTMUEN0H (CTMU Enable 0 High) ................... 455
ADCTMUEN0L (CTMU Enable,0 Low) .................... 455
ADCTMUEN1H (CTMU Enable 1 High) .................. 454
ADCTMUEN1L (CTMU Enable 1 Low) .................... 454
ADHIT0H (A/D Scan Compare Hit 0 High) .............. 451
ADHIT0L (A/D Scan Compare Hit 0 Low) ............... 451
ADHIT1H (A/D Scan Compare Hit 1 High) .............. 450
ADHIT1L (A/D Scan Compare Hit 1 Low) ............... 450
ALRMCFG (Alarm Configuration) ............................ 302
ALRMDAY (Alarm Day Value) ................................. 307
ALRMHR (Alarm Hours Value) ................................ 308
ALRMMIN (Alarm Minutes Value) ........................... 309
ALRMMNTH (Alarm Month Value) .......................... 307
ALRMRPT (Alarm Repeat) ...................................... 303
ALRMSEC (Alarm Seconds Value) ......................... 309
ALRMWD (Alarm Weekday Value) .......................... 308
ANCON1 (Analog Select Control 1) ........................ 438
ANCON2 (Analog Select Control 2) ........................ 439
ANCON3 (Analog Select Control 3) ........................ 440
BAUDCONx (Baud Rate Control x) ......................... 414
BDnSTAT ................................................................ 535
BDnSTAT (Buffer Descriptor n Status, CPU Mode) 536
BDnSTAT (Buffer Descriptor n Status, SIE Mode) .. 537
BDnSTAT (SIE Mode) ............................................. 537
Buffer Descriptors, Summary .................................. 539
CCPRxH (CCPx Period High Byte) ......................... 342
CCPRxL (CCPx Period Low Byte) ........................... 342
CCPTMRS0 (CCP Timer Select 0) .......................... 319
CCPTMRS1 (CCP Timer Select 1) .......................... 340
CCPTMRS2 (CCP Timer Select 2) .......................... 341
CCPxCON (CCP4-CCP10 Control) ......................... 339
CCPxCON (Enhanced Capture/Compare/PWMx
Control) ............................................................ 318
CMSTAT (Comparator Status) ................................ 491
CMxCON (Comparator Control x) ........................... 490
CONFIG1H (Configuration 1 High) .......................... 555
CONFIG1L (Configuration 1 Low) ........................... 555
CONFIG2H (Configuration 2 High) .......................... 557
CONFIG2L (Configuration 2 Low) ........................... 556
CONFIG3L (Configuration 3 Low) ........................... 558
CONFIG4H (Configuration 4 High) .......................... 559
CONFIG4L (Configuration 4 Low) ........................... 559
CONFIG5H (Configuration 5 High) .......................... 561
CONFIG5L (Configuration 5 Low) ........................... 560
CONFIG6H (Configuration 6 High) .......................... 563
CONFIG6L (Configuration 6 Low) ........................... 562
CONFIG7L (Configuration 7 Low) ........................... 564
CONFIG8H (Configuration 8 High) .......................... 566
CONFIG8L (Configuration 8 Low) ........................... 565
CTMUCON (CTMU Control) .................................... 508
CTMUCON1 (CTMU Current Control 1) .................. 509
CTMUCON2 (CTMU Current Control 2) .................. 510
CTMUCON3 (CTMU Current Control 3) .................. 511
CVRCONH (Comparator Voltage Reference
Control High) ................................................... 497
CVRCONL (Comparator Voltage Reference
Control Low) .................................................... 498
DAY (Day Value) ..................................................... 305
DEVID1 (Device ID 1) .............................................. 567
DEVID2 (Device ID 2) .............................................. 567
DMACON1 (DMA Control 1) .................................... 364
DMACON2 (DMA Control 2) .................................... 365
DSCONH (Deep Sleep Control High) ........................ 77
DSCONL (Deep Sleep Control Low) ......................... 77
DSWAKEH (Deep Sleep Wake-up Source High) ...... 78
DSWAKEL (Deep Sleep Wake-up Source Low) ....... 78
PIC18F97J94 FAMILY
DS30575A-page 686 2012 Microchip Technology Inc.
ECCPxAS (ECCPx Auto-Shutdown Control) ........... 331
ECCPxDEL (Enhanced PWM Control) .................... 334
EECON1 (EEPROM Control 1) ................................ 145
HLVDCON (High/Low-Voltage Detect Control) ........ 501
HOUR (Hour Value) .................................................305
INTCON (Interrupt Control) ......................................170
INTCON2 (Interrupt Control 2) ................................. 171
INTCON3 (Interrupt Control 3) ................................. 172
IOCF (Interrupt-on-Change Flag) .............................194
IOCN (Interrupt-on-Change Negative Edge) ............ 194
IOCP (Interrupt-on-Change Positive Edge) ............. 194
IPR1 (Peripheral Interrupt Priority 1) ........................ 186
IPR2 (Peripheral Interrupt Priority 2) ........................ 187
IPR3 (Peripheral Interrupt Priority 3) ........................ 188
IPR4 (Peripheral Interrupt Priority 4) ........................ 189
IPR5 (Peripheral Interrupt Priority 5) ........................ 190
IPR6 (Peripheral Interrupt Priority 6) ........................ 191
LCDCON (LCD Control) ...........................................246
LCDDATAx (LCD Data x) ........................................ 250
LCDPS (LCD Phase) ...............................................248
LCDREFH (LCD Reference Ladder Control High) ... 256
LCDREFL (LCD Reference Ladder Control Low) .... 257
LCDREG (LCD Charge Pump Control) .................... 247
LCDREG (LCD Voltage Regulator Control) ............. 258
LCDSEx (LCD Segment x Enable) .......................... 249
MDCARH (Modulation Carrier High Control) ... 243, 244
MDCON (Modulation Control Register) ................... 241
MDSRC (Modulation Source Control) ...................... 242
MEMCON (External Memory Bus Control) .............. 154
MINUTE (Minute Value) ........................................... 306
MONTH (Month Value) ............................................ 304
ODCON1 (Peripheral Open-Drain Control 1) ........... 199
ODCON2 (Peripheral Open-Drain Control 2) ........... 200
OSCCON (Oscillator Control) .................................... 41
OSCCON2 (Oscillator Control 2) ...............................42
OSCCON3 (Oscillator Control 3) ...............................43
OSCCON4 (Oscillator Control 4) ...............................43
OSCTUNE (FRC Oscillator Tuning) ........................... 44
PADCFG (Pad Configuration) .................................. 198
PIE1 (Peripheral Interrupt Enable 1) ........................ 180
PIE2 (Peripheral Interrupt Enable 2) ........................ 181
PIE3 (Peripheral Interrupt Enable 3) ........................ 182
PIE4 (Peripheral Interrupt Enable 4) ........................ 183
PIE5 (Peripheral Interrupt Enable 5) ........................ 184
PIE6 (Peripheral Interrupt Enable 6) ........................ 185
PIR1 (Peripheral Interrupt Request (Flag) 1) ........... 173
PIR2 (Peripheral Interrupt Request (Flag) 2) ........... 174
PIR3 (Peripheral Interrupt Request (Flag) 3) ........... 175
PIR4 (Peripheral Interrupt Request (Flag) 4) ........... 176
PIR5 (Peripheral Interrupt Request (Flag) 5) ........... 178
PIR6 (Peripheral Interrupt Request (Flag) 6) ........... 179
PSPCON (Parallel Slave Port Control) .................... 222
PSTRxCON (Pulse Steering Control) ...................... 335
RCON (Reset Control 1) .................................... 86, 192
RCON2 (Reset Control 2) .................................. 87, 569
RCON3 (Reset Control 3) ..........................................88
RCON4 (Reset Control 4) ..........................................89
RCSTAx (EUSARTx Receive Status and Control) ... 413
REFOxCON (Reference Clock Output Control) ......... 46
REFOxCON1 (Reference Clock Output Control 1) .... 47
REFOxCON2 (Reference Clock Output Control 2) .... 48
REFOxCON3 (Reference Clock Output Control 3) .... 48
Reserved .................................................................. 303
RPORn_n (Remapped Peripheral Output n) ........... 230
RTCCAL (RTCC Calibration) ................................... 300
RTCCON1 (RTCC Configuration 1) ......................... 299
RTCCON2 (RTC Configuration) .............................. 301
SECOND (Second Value) ........................................ 306
SSPxCON1 (MSSPx Control 1, I2C Master Mode) .. 374
SSPxCON1 (MSSPx Control 1,
SPI Mode) ................................ 354, 355, 376, 378
SSPxCON2 (MSSPx Control 2, I2C Master Mode) .. 375
SSPxCON2 (MSSPx Control 2, I2C Slave Mode) .... 377
SSPxMSK (I2C Slave Address Mask, 7-Bit
Masking Mode) ................................................ 379
SSPxSTAT (MSSPx Status, I2C Master Mode) ....... 373
SSPxSTAT (MSSPx Status, SPI Mode) .................. 353
STATUS .................................................................. 135
STKPTR (Stack Pointer) .......................................... 116
T0CON (Timer0 Control) ......................................... 281
TxCON (Timerx Control, Timer1/3/5) ....................... 285
TxCON (Timerx Control, Timer2/4/6/8) .................... 295
TxGCON (Timerx Gate Control) .............................. 286
TXSTAx (EUSARTx Transmit Status and Control) .. 412
UADDR .................................................................... 533
UCFG (USB Configuration) ..................................... 529
UCON (USB Control) ............................................... 527
UEIE (USB Error Interrupt Enable) .......................... 545
UEIR (USB Error Interrupt Status) ........................... 544
UEPn (USB Endpoint n Control) .............................. 532
UFRMH:UFRML ...................................................... 533
UIE (USB Interrupt Enable) ..................................... 543
UIR (USB Interrupt Status) ...................................... 541
USTAT (USB Status) ............................................... 531
WEEKDAY (Weekday Value) .................................. 305
YEAR (Year Value) .................................................. 304
RESET ............................................................................. 605
Reset ................................................................................. 85
Brown-out Reset (BOR)
Features ............................................................ 93
Configuration Mismatch (CM) .................................... 93
Master Clear (MCLR) ................................................. 92
Power-on Reset (POR) .............................................. 90
RCON Registers ........................................................ 85
RESET Instruction ..................................................... 94
Stack Underflow/Overflow ......................................... 94
Watchdog Timer Reset (WDT) .................................. 92
Resets ........................................................................ 85, 553
Brown-out Reset (BOR) ........................................... 553
Oscillator Start-up Timer (OST) ............................... 553
Power-on Reset (POR) ............................................ 553
Power-up Timer (PWRT) ......................................... 553
Retention Sleep Mode
Delay Times for Exit (table) ....................................... 70
RETFIE ............................................................................ 606
RETLW ............................................................................ 606
RETURN .......................................................................... 607
Return Address Stack ...................................................... 115
Return Stack Pointer (STKPTR) ...................................... 116
Revision History ............................................................... 677
RLCF ............................................................................... 607
RLNCF ............................................................................. 608
RRCF ............................................................................... 608
RRNCF ............................................................................ 609
RTCC
Alarm ....................................................................... 313
Configuring ...................................................... 313
Interrupt ........................................................... 314
Mask Settings .................................................. 314
Alarm Value Registers (ALRMVAL) ......................... 307
2012 Microchip Technology Inc. DS30575A-page 687
PIC18F97J94 FAMILY
Associated Alarm Value Registers ........................... 316
Associated Control Registers ................................... 316
Associated Value Registers ..................................... 316
Control Registers ..................................................... 299
Operation ................................................................. 310
Calibration ........................................................ 313
Clock Source ................................................... 311
Digit Carry Rules .............................................. 311
General Functionality ....................................... 312
Leap Year ........................................................ 312
Register Mapping ............................................. 312
ALRMVAL ................................................ 313
RTCVAL ................................................... 312
Safety Window for Register Reads and Writes 312
Write Lock ........................................................ 312
Register Interface ..................................................... 310
Register Maps .......................................................... 316
Reset ........................................................................ 315
Device .............................................................. 315
Power-on Reset (POR) .................................... 315
RTCEN Bit Write ...................................................... 310
Sleep Mode .............................................................. 315
Value Registers (RTCVAL) ...................................... 303
S
Secondary Oscillator (SOSC) ............................................ 55
Enabling ..................................................................... 55
Serial Peripheral Interface. See SPI Mode.
SETF ................................................................................ 609
Shoot-Through Current .................................................... 333
SLEEP ............................................................................. 610
Sleep Mode
Delay Times for Exit (table) ........................................ 70
Software Simulator (MPLAB SIM) .................................... 627
Special Event Trigger. See Compare (CCP Module).
Special Event Trigger. See Compare (ECCP Mode).
SPI Mode (MSSP) ............................................................ 352
Bus Mode Compatibility ........................................... 361
Clock Speed, Interactions ........................................ 361
DMA Module ............................................................ 362
I/O Pin Considerations ..................................... 362
Idle, Sleep Considerations ............................... 362
RAM to RAM Copy Operations ........................ 362
Registers .......................................................... 362
Effects of a Reset ..................................................... 361
Enabling SPI I/O ...................................................... 357
Master Mode ............................................................ 358
Master/Slave Connection ......................................... 357
Operation ................................................................. 356
Operation in Power-Managed Modes ...................... 361
Slave Mode .............................................................. 359
Slave Select Synchronization .................................. 359
SPI Clock ................................................................. 358
SSPxBUF Register .................................................. 358
SSPxSR Register ..................................................... 358
Typical Connection .................................................. 357
SSPOV ............................................................................. 401
SSPOV Status Flag ......................................................... 401
SSPxSTAT Register
R/W Bit ............................................................. 380, 383
ST
Block Diagram ............................................................ 60
Stack Full/Underflow Resets ............................................ 117
SUBFSR .......................................................................... 621
SUBFWB .......................................................................... 610
SUBLW ............................................................................ 611
SUBULNK ........................................................................ 621
SUBWF ............................................................................ 611
SUBWFB ......................................................................... 612
SWAPF ............................................................................ 612
T
Table Reads/Table Writes ............................................... 117
TBLRD ............................................................................. 613
TBLWT ............................................................................ 614
Timer0 ............................................................................. 281
Operation ................................................................. 282
Overflow Interrupt .................................................... 283
Prescaler ................................................................. 283
Switching Assignment ..................................... 283
Prescaler Assignment (PSA Bit) .............................. 283
Prescaler Select (T0PS2:T0PS0 Bits) ..................... 283
Reads and Writes in 16-Bit Mode ............................ 282
Timer1/3/5 ....................................................................... 284
16-Bit Read/Write Mode .......................................... 288
Gates ....................................................................... 289
Operation ................................................................. 287
Oscillator .................................................................. 284
Overflow Interrupt ............................................ 284, 293
Special Event Trigger (ECCP) ................................. 293
TMRxH Register ...................................................... 284
TMRxL Register ....................................................... 284
Using SOSC Oscillator as Clock Source ................. 288
Timer2
PR2 Register ........................................................... 348
TMR2 to PR2 Match Interrupt .................................. 348
Timer2/4/6/8 .................................................................... 294
Interrupt ................................................................... 295
MSSP Clock Shift .................................................... 295
Operation ................................................................. 294
Output ...................................................................... 295
Postscaler. See Postscaler, Timer2/4/6/8.
Prescaler. See Prescaler, Timer2/4/6/8.
PRx Register ........................................................... 294
TMRx Register ......................................................... 294
Timing Diagrams
’0’ Bit Data IrDA Encoding Scheme ......................... 432
A/D Conversion ....................................................... 661
Asynchronous Reception ......................................... 424
Asynchronous Transmission ................................... 422
Asynchronous Transmission (Back-to-Back) ........... 422
Automatic Baud Rate Calculation ............................ 420
Auto-Sample Start, Conversion Trigger Based
Conversion Start .............................................. 465
Auto-Wake-up Bit (WUE) During Normal Operation 425
Auto-Wake-up Bit (WUE) During Sleep ................... 425
Baud Rate Generator with Clock Arbitration ............ 398
BCLK Output vs. BRG Programming ...................... 431
BRG Overflow Sequence ........................................ 420
BRG Reset Due to SDAx Arbitration During
Start Condition ................................................. 407
Brown-out Reset (BOR) ........................................... 647
Bus Collision During Repeated Start Condition
(Case 1) ........................................................... 408
Bus Collision During Repeated Start Condition
(Case 2) ........................................................... 408
Bus Collision During Start Condition (SCLx = 0) ..... 407
Bus Collision During Start Condition (SDAx Only) .. 406
Bus Collision During Stop Condition (Case 1) ......... 409
Bus Collision During Stop Condition (Case 2) ......... 409
Bus Collision for Transmit and Acknowledge .......... 405
Capture/Compare/PWM (CCP1, CCP2) .................. 650
PIC18F97J94 FAMILY
DS30575A-page 688 2012 Microchip Technology Inc.
CLKO and I/O .......................................................... 644
Clock Jitter Causing Pulse Between Consecutive
Zeros ................................................................ 433
Clock Synchronization .............................................391
Clock Transition ......................................................... 58
Clock/Instruction Cycle ...................................... 38, 118
Converting 1 Channel 16 Times per Interrupt .......... 477
Converting 1 Channel, Auto-Sample Start, Manual
Conversion Start .............................................. 462
Converting 1 Channel, Auto-Sample Start, TADad
Based Conversion Start ...................................464
Converting 1 Channel, Manual Sample Start,
TADad Based Conversion Start ........................ 463
Converting 2 Inputs Using Alternating Input
Selections ........................................................483
Converting a Single Channel, Once per Interrupt
Using Dual, 8-Word Buffers .............................481
DSM Carrier High Synchronization
(MDCHSYNC = 1, MDCLSYNC = 0) ............... 238
DSM Carrier Low Synchronization
(MDCHSYNC = 0, MDCLSYNC = 1) ............... 239
DSM Full Synchronization (MDCHSYNC = 1,
MDCLSYNC = 1) ............................................. 239
DSM No Synchronization (MDCHSYNC = 0,
MDCLSYNC = 0) ............................................. 238
DSM On-Off Keying (OOK) Synchronization ...........238
EUSARTx Synchronous Transmission
(Master/Slave) ..................................................659
EUSARTx/AUSARTx Synchronous Receive
(Master/Slave) ..................................................659
Example SPI Master Mode (CKE = 0) ..................... 651
Example SPI Master Mode (CKE = 1) ..................... 652
Example SPI Slave Mode (CKE = 0) ....................... 653
Example SPI Slave Mode (CKE = 1) ....................... 654
External Clock .......................................................... 642
External Memory Bus for SLEEP (Extended
Microcontroller Mode) .............................. 160, 162
External Memory Bus for TBLRD (Extended
Microcontroller Mode) .............................. 160, 162
Fail-Safe Clock Monitor (FSCM) .............................. 572
First Start Bit Timing ................................................ 399
Full-Bridge PWM Output .......................................... 328
Half-Bridge PWM Output ................................. 326, 333
High-Voltage Detect Operation (VDIRMAG = 1) ...... 504
HLVD Characteristics ...............................................648
I2C Acknowledge Sequence .................................... 404
I2C Bus Data ............................................................ 656
I2C Bus Start/Stop Bits .............................................655
I2C Master Mode (7 or 10-Bit Transmission) ........... 402
I2C Master Mode (7-Bit Reception) .......................... 403
I2C Slave Mode (10-Bit Reception, SEN = 0,
MSK = 01001) .................................................. 387
I2C Slave Mode (10-Bit Reception, SEN = 0) .......... 388
I2C Slave Mode (10-Bit Reception, SEN = 1) .......... 393
I2C Slave Mode (10-Bit Transmission) ..................... 389
I2C Slave Mode (7-bit Reception, SEN = 0,
MSK = 01011) .................................................. 385
I2C Slave Mode (7-Bit Reception, SEN = 0) ............ 384
I2C Slave Mode (7-Bit Reception, SEN = 1) ............ 392
I2C Slave Mode (7-Bit Transmission) ....................... 386
I2C Slave Mode General Call Address Sequence (7 or
10-Bit Addressing Mode) ................................. 394
I2C Stop Condition Receive or Transmit Mode ........ 404
Inverted IrDA Encoding (TXCKP = 1) ...................... 432
Inverted Polarity Decoding Results (RXDTP = 1) .... 433
IrDA Encoding Scheme ........................................... 432
LCD Reference Ladder Power Mode Switching ...... 254
LCD Sleep Entry/Exit When SLPEN = 1 or
CS1:CS0 = 00 ................................................. 280
Low-Voltage Detect Operation (VDIRMAG = 0) ...... 504
Macro View of IrDA Decoding Scheme
(RXDTP = 0) .................................................... 433
Manual Sample Start, Conversion Trigger Based
Conversion Start .............................................. 465
MSSPx I2C Bus Data ............................................... 657
MSSPx I2C Bus Start/Stop Bits ............................... 657
Parallel Slave Port (PSP) Read ............................... 223
Parallel Slave Port (PSP) Write ............................... 222
POR Module for Rising VDD ...................................... 91
Program Memory Fetch (8-bit) ................................. 645
Program Memory Read ........................................... 646
PWM Auto-Shutdown with Auto-Restart Enabled
(PxRSEN = 1) .................................................. 332
PWM Auto-Shutdown with Firmware Restart
(PxRSEN = 0) .................................................. 332
PWM Direction Change ........................................... 329
PWM Direction Change at Near 100% Duty Cycle .. 330
PWM Output ............................................................ 348
PWM Output (Active-High) ...................................... 324
PWM Output (Active-Low) ....................................... 325
Repeated Start Condition ........................................ 400
Reset, Watchdog Timer (WDT), Oscillator Start-up
Timer (OST) and Power-up Timer (PWRT) ..... 647
Scanning All 16 Inputs per Single Interrupt ............. 479
Send Break Character Sequence ............................ 426
Slave Synchronization ............................................. 359
SPI Mode (Master Mode) ......................................... 358
SPI Mode (Slave Mode, CKE = 0) ........................... 360
SPI Mode (Slave Mode, CKE = 1) ........................... 360
Steering Event at Beginning of Instruction
(STRSYNC = 1) ............................................... 336
Steering Event at End of Instruction
(STRSYNC = 0) ............................................... 336
Synchronous Reception (Master Mode, SREN) ...... 429
Synchronous Transmission ..................................... 428
Synchronous Transmission (Through TXEN) .......... 428
Timer Pulse Generation ........................................... 315
Timer0 and Timer1 External Clock .......................... 649
Timer1/3/5 Gate Count Enable Mode ...................... 289
Timer1/3/5 Gate Single Pulse Mode ........................ 291
Timer1/3/5 Gate Single Pulse/Toggle Combined
Mode ................................................................ 292
Timer1/3/5 Gate Toggle Mode ................................. 290
Transition for Two-Speed Start-up
(INTOSC to HSPLL) ........................................ 570
Waveforms and Interrupt in Quarter Duty Cycle
Drive ................................................................ 278
Timing Diagrams and Specifications
Capture/Compare/PWM Requirements ................... 650
CLKO and I/O Requirements ........................... 644, 646
EUSARTx/AUSARTx Synchronous Receive
Requirements .................................................. 659
EUSARTx/AUSARTx Synchronous Transmission
Requirements .................................................. 659
Example SPI Mode Requirements (Master Mode,
CKE = 0) .......................................................... 651
Example SPI Mode Requirements (Master Mode,
CKE = 1) .......................................................... 652
Example SPI Mode Requirements (Slave Mode,
CKE = 0) .......................................................... 653
2012 Microchip Technology Inc. DS30575A-page 689
PIC18F97J94 FAMILY
Example SPI Slave Mode Requirements (CKE = 1) 654
External Clock Requirements .................................. 642
HLVD Characteristics ............................................... 648
I2C Bus Data Requirements (Slave Mode) .............. 656
I2C Bus Start/Stop Bits Requirements
(Slave Mode) ................................................... 655
Internal RC Accuracy (INTOSC) .............................. 643
MSSPx I2C Bus Data Requirements ........................ 658
MSSPx I2C Bus Start/Stop Bits Requirements ........ 657
PLL Clock ................................................................. 643
Program Memory Fetch Requirements (8-Bit) ......... 645
Reset, Watchdog Timer, Oscillator Start-up Timer,
Power-up Timer and Brown-out Reset
Requirements .................................................. 647
Timer0 and Timer1 External Clock Requirements ... 649
Top-of-Stack Access ........................................................ 115
TSTFSZ ........................................................................... 615
Two-Speed Start-up ........................................... 62, 553, 570
Special Considerations for Use .................................. 62
Two-Word Instructions
Example Cases ........................................................ 119
TXSTAx Register
BRGH Bit ................................................................. 416
U
Universal Serial Bus ......................................................... 525
Address Register (UADDR) ..................................... 533
Associated Registers ............................................... 549
Buffer Descriptor Table ............................................ 534
Buffer Descriptors .................................................... 534
Address Validation ........................................... 537
Assignment in Different Buffering Modes ........ 539
BDnSTAT Register (CPU Mode) ..................... 535
BDnSTAT Register (SIE Mode) ....................... 537
Byte Count ....................................................... 537
Memory Map .................................................... 538
Ownership ........................................................ 534
Ping-Pong Buffering ......................................... 538
Register Summary ........................................... 539
Status and Configuration ................................. 534
Endpoint Control ...................................................... 532
External Pull-up Resistors ........................................ 530
Eye Pattern Test Enable .......................................... 530
Firmware and Drivers ............................................... 549
Frame Number Registers ......................................... 533
Internal Pull-up Resistors ......................................... 530
Internal Transceiver ................................................. 528
Interrupts .................................................................. 540
and USB Transactions ..................................... 540
Oscillator Requirements ........................................... 549
Overview .......................................................... 525, 550
Class Specifications and Drivers ..................... 551
Descriptors ....................................................... 551
Enumeration .................................................... 551
Frames ............................................................. 550
Layered Framework ......................................... 550
Power ............................................................... 550
Speed .............................................................. 551
Transfer Types ................................................. 550
Ping-Pong Buffer Configuration ............................... 530
Power Modes ........................................................... 546
Bus Power Only ............................................... 546
Dual Power with Self-Power Dominance ......... 546
Self-Power Only ............................................... 546
Transceiver Current Consumption ................... 547
RAM ......................................................................... 533
Memory Map .................................................... 533
Status and Control ................................................... 526
UFRMH:UFRML Registers ...................................... 533
USB
Module Specifications .............................................. 639
USB. See Universal Serial Bus.
V
Voltage-Frequency Graph ............................................... 630
W
Watchdog Timer (WDT) ........................................... 553, 568
Control Register ....................................................... 569
During Oscillator Failure .......................................... 571
Programming Considerations .................................. 568
WCOL ...................................................... 399, 400, 401, 404
WCOL Status Flag ................................... 399, 400, 401, 404
WWW Address ................................................................ 691
WWW, On-Line Support ...................................................... 7
X
XORLW ........................................................................... 615
XORWF ........................................................................... 616
PIC18F97J94 FAMILY
DS30575A-page 690 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 691
PIC18F97J94 FAMILY
THE MICROCHIP WEB SITE
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Customers should contact their distributor,
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PIC18F97J94 FAMILY
DS30575A-page 692 2012 Microchip Technology Inc.
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip
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DS30575APIC18F97J94 Family
1. What are the best features of this document?
2. How does this document meet your hardware and software development needs?
3. Do you find the organization of this document easy to follow? If not, why?
4. What additions to the document do you think would enhance the structure and subject?
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2012 Microchip Technology Inc. DS30575A-page 693
PIC18F97J94 FAMILY
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO. X/XX XXX
PatternPackageTemperature
Range
Device
Device PIC18F97J94, PIC18F96J94, PIC18F95J94, PIC18F87J94,
PIC18F86J94, PIC18F85J94, PIC18F67J94, PIC18F66J94,
PIC18F65J94
VDD range 2.0 to 3.6V
Temperature Range I = -40C to +85C (Industrial)
Package PT = TQFP (Thin Quad Flatpack)
PF = TQFP (100-Pin Thin Quad, 14x14x1 Body)
Pattern QTP, SQTP, Code or Special Requirements
(blank otherwise)
Examples:
a) PIC18F97J94-I/PT = Industrial temp., TQFP
package, QTP pattern #301.
b) PIC18F87J94-I/PT = Industrial temp., TQFP
package.
Note 1: T = in tape and reel PLCC, and TQFP
packages only.
PIC18F97J94 FAMILY
DS30575A-page 694 2012 Microchip Technology Inc.
NOTES:
2012 Microchip Technology Inc. DS30575A-page 695
Information contained in this publication regarding device
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MICROCHIP MAKES NO REPRESENTATIONS OR
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Trademarks
The Microchip name and logo, the Microchip logo, dsPIC,
FlashFlex, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro,
PICSTART, PIC32 logo, rfPIC, SST, SST Logo, SuperFlash
and UNI/O are registered trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor,
MTP, SEEVAL and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A.
Silicon Storage Technology is a registered trademark of
Microchip Technology Inc. in other countries.
Analog-for-the-Digital Age, Application Maestro, BodyCom,
chipKIT, chipKIT logo, CodeGuard, dsPICDEM,
dsPICDEM.net, dsPICworks, dsSPEAK, ECAN,
ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial
Programming, ICSP, Mindi, MiWi, MPASM, MPF, MPLAB
Certified logo, MPLIB, MPLINK, mTouch, Omniscient Code
Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit,
PICtail, REAL ICE, rfLAB, Select Mode, SQI, Serial Quad I/O,
Total Endurance, TSHARC, UniWinDriver, WiperLock, ZENA
and Z-Scale are trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
GestIC and ULPP are registered trademarks of Microchip
Technology Germany II GmbH & Co. & KG, a subsidiary of
Microchip Technology Inc., in other countries.
All other trademarks mentioned herein are property of their
respective companies.
© 2012, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
ISBN: 9781620766231
Note the following details of the code protection feature on Microchip devices:
• Microchip products meet the specification contained in their particular Microchip Data Sheet.
• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
• Microchip is willing to work with the customer who is concerned about the integrity of their code.
• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
QUALITY MANAGEMENT S
YSTEM
CERTIFIED BY DNV
== ISO/TS 16949 ==
DS30575A-page 696 2012 Microchip Technology Inc.
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Worldwide Sales and Service
11/29/11
