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M25P80
OPERATING FEATURES
Page Prog ram m i ng
To program one data byte, two instructions are required: Write Enable (WREN), which is one by te,
and a Page Program (PP) sequence, which consists of four bytes plus data. This is followed by the
internal Program cycle (of duration t
PP
).
To spread this overhead, the Page P rogram (PP)
instruction allows up to 256 bytes to be programmed at a time (changing bits from 1 to 0), provided that they lie in consecutive addresses on the
same page of memory.
Sector Erase and Bulk Erase
The Page Program (PP) instruction allows bits to
be reset from 1 to 0. Before this can be applied, the
bytes of memory need to have been e rased to a ll
1s (FFh). This can be achieved either a sector 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 t
SE
or tBE).
The Erase instruction must be preceeded by a
Write Enable (WREN) instruction.
Polling During a Write, 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 n ot waiting for the worst
case delay (t
W
, tPP, tSE, or tBE). The Write In
Progress (WIP) bit is provided in the Status Register so that the application program can monitor its
value, polling it to establish when the previous
Write cycle, Program cycle or Erase cycle is complete.
Active Power, Stand-by Power and De ep
Power-Down Modes
When Chip Select (S) is Low, the device is enabled, and in the Active Power mode.
When Chip Select (S
) is High, the device is disabled, but could remain in the Active Power mode
until all internal cycles have completed (Pro gram,
Erase, Write Status Register). The device then
goes in to the Stand-by P ower mode. T he device
consumption drops to I
CC1
.
The Deep Power-down mode is entered when the
specific instruction (the Enter Deep Power-down
Mode (DP) instruction) is executed. The device
consumption drops further to I
CC2
. The device remains in this mode until another specific instruction (the Release from Deep Power-down Mode
and Read Electronic S ignature (RES ) instruction)
is executed.
All other instructions are ignored while the device
is in the Deep Power-down mode. This can be
used as an extra software 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 num ber of status
and control bits that can be read or set (as appropriate) by specific instructions.
WIP bit. The Write In Progress (WIP) bit indicates
whether the memory is busy with a Write Sta tus
Register, Program or Erase cycle.
WEL bit. Th e Write Enable Latch (WEL) bit indicates the status of the internal Write Enable Latch.
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 Erase 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 an d Write Protect (W
)
signal allow the device to be put in the Hardware
Protected mode. In this mode, the non-volatile bits
of the Status Register (SRWD, BP2, BP1, BP0)
become read-only bits.