M25P20 Serial Flash Embedded Memory
RELEASE from Deep Power-Down
RELEASE from Deep Power-Down
Once the device has entered deep power-down mode, all commands are ignored except
RELEASE from deep power-down. Executing either of these commands takes the device
out of the deep power-down mode. Except while an ERASE, PROGRAM, or WRITE STA-
TUS REGISTER cycle is in progress, the RELEASE from deep power-down command al-
ways provides access to the 8-bit electronic signature of the device, and can be applied
even if the deep power-down mode has not been entered.
Each command is executed by first driving S LOW to select the device. The command
code is followed by 3 dummy bytes, each bit being latched-in on DQ0 during the rising
edge of C. Then, the 8-bit electronic signature, stored in the memory, is shifted out on
DQ1, each bit being shifted out during the falling edge of C.
S must be driven LOW the entire duration of the sequence for the electronic signature to
be read. However, driving S# HIGH after the command code, but before the entire 8-bit
electronic signature has been output for the first time, still ensures that the device is put
into standby mode.
The RELEASE from deep power-down command is terminated by driving S# HIGH after
the electronic signature has been read at least once. Sending additional clock cycles on
C, while S is driven LOW, causes the electronic signature to be output repeatedly.
When S# is driven HIGH, the device is put in standby mode immediately unless it was
previously in deep power-down mode. If previously in deep power-down mode, the de-
vice transitions to standby mode with delay as follows:
• When S# is driven HIGH before the electronic signature is read, transition to standby
mode is delayed by tRES1, as shown in the RELEASE from deep power-down com-
mand sequence. S# must remain HIGH for at least tRES1(MAX).
• When S# is driven HIGH after the electronic signature is read, transition to standby
mode is delayed by tRES2. S# must remain HIGH for at least tRES2(MAX), as specified
in the AC Characteristics tables.
Once in standby mode, the device waits to be selected so that it can receive, decode,
and execute instructions. Any release from deep power-down command issued while an
ERASE, PROGRAM, or WRITE cycle is in progress is rejected and has no effect on the
cycle in progress.
Figure 19: RELEASE from Deep Power-Down Sequence
0
7
C
DQ0
DQ1
tRDP
LSB
Command
High-Z
MSB
Deep Power-Down Mode
Standby Mode
Don’t Care
PDF: 09005aef8456656e
m25p20.pdf - Rev. A 2/13 EN
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