M25P64 Datasheet, PDF (13/50 Pages) STMicroelectronics – 64 Mbit, Low Voltage, Serial Flash Memory With 50MHz SPI Bus Interface

M25P64
4
Operating features
Operating features
4.1
Page Programming
To program one data byte, two instructions are required: Write Enable (WREN), which is one
byte, 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 Program (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.
For optimized timings, it is recommended to use the Page Program (PP) instruction to
program all consecutive targeted Bytes in a single sequence versus using several Page
Program (PP) sequences with each containing only a few Bytes (see Page Program (PP)
and Table 14: AC characteristics).
4.2
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 erased to all 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 t_BE).
The Erase instruction must be preceded by a Write Enable (WREN) instruction.
4.3
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 not waiting for the worst case delay (t_W, t_PP, t_SE, or t_BE). 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.
4.4
Fast Program/Erase mode
The Fast Program/Erase mode is used to speed up programming/erasing. The device
enters the Fast Program/Erase mode during the Page Program, Sector Erase or Bulk Erase
instruction whenever a voltage equal to V_PPH is applied to the W/V_PP pin.
The use of the Fast Program/Erase mode requires specific operating conditions in addition
to the normal ones (V_CC must be within the normal operating range):
● the voltage applied to the W/V_PP pin must be equal to V_PPH (see Table 10)
● ambient temperature, T_A must be 25°C ±10°C,
● the cumulated time during which W/V_PP is at V_PPH should be less than 80 hours
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