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M25P80
OPERATING FEATURE S
Page P rogramm i ng
To program one dat a byte, t wo ins tructions are re-
quired: Write Enable (WREN), which is one byte,
and a Page Program (PP) sequence, which con-
sists of four bytes plus data. This is f ollowed by the
internal Program cycle (of duration tPP).
To spread this ove rhead, the Page P rogram (PP)
instruction allows up to 256 bytes to be pro-
grammed at a time (changing bits from 1 to 0), pro-
vided that they lie in consecutive addresses on the
same page of memory.
Sector Erase and Bul k Erase
The Page Program (PP) instruction allows bits to
be reset from 1 to 0. Before this can be applied, the
bytes of memo ry need to hav e been erased to a ll
1s (FFh). Thi s can be achieved either a sec tor at a
time, using the Sector Erase (SE) instruction, or
throughout the entire memory, using the Bulk
Erase (BE) instruction. This starts an internal
Erase cycle (of duration tSE or tBE).
The Erase instruction must be preceeded by a
Write Enabl e (WREN) instruction.
Polling Duri ng a Wri te, Program or Erase Cycle
A further improvement in the time to Write Status
Register (WRSR), Program (PP) or Erase (SE or
BE) can be achieved by not waiting for the worst
case delay (tW, tPP, tSE, or tBE). The Write In
Progress (WIP) bit is provided in t he Status Regi s-
ter so that the application program can m onitor its
value, polling it to establish when the previous
Write cycle, Pro gram cycle or Erase cycle is com-
plete.
Active Power, St a nd - b y Power and De ep
Power-Down Modes
When Chip Select (S) is Low, the device is en-
abled, and in the Active Power mode.
When Chip Select (S) is High, the device is dis-
abled, but could remain i n the Active Power mode
until all internal cycles hav e completed (P rogram,
Erase, Write Status Register). The device then
goes in t o the Stand-by P ower mode. T he dev ice
consumpt i on drops to ICC1.
The Deep Power-down mode is entered when the
specific instruction (the Enter Deep Power-down
Mode (DP) instruction) is executed. The device
consump tion drops further to ICC2. The device re-
mains in this mode until another specific instruc-
tion (the Release from Deep Power-down Mode
and Read Electro nic Signature (RE S) instruction)
is executed.
All other instructions are igno red whil e the dev ice
is in the Deep Power-down mode. This can be
used as an ext ra soft ware protection mecha nism,
when the device is not in active use, to protect the
device from inadvertant Write, Program or Erase
instructions.
Status Register
The Status Register contains a number of status
and control bits that can be read or set (as appro-
priate) by specific instructions.
WIP bit. The Writ e In Progress (WIP) bit indic ates
whether the memory is busy with a Write Status
Register, Program or Era se cycle.
WEL bit. The Write Enable Latch (WEL) bit indi-
cates the status of the int ernal Write Enable Latc h.
BP2, BP1, BP0 bits. The Block Protect (BP2,
BP1, BP0) bits are non-volatile. They define the
size of the area to be software protected against
Program and Eras e instructions.
SRWD bit. The Status Register Write Disable
(SRWD) bit is operated in conjunction with the
Write Protect (W) signal. The Status Register
Write Disable (SRWD) bit and Write Protect (W)
signal allow the device to be put in the Hardware
Protected mode. In this mode, the non-v olatile bit s
of the Status Register (SRWD, BP2, BP1, BP0)
become read-only bits.