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M25P05

Figure 17. Release from Deep Power-down and Read Electronic Signature (RES) Sequence

Release from Deep Power-down and Read

Electronic Signature (RES)

Once the device has entered the Deep Power-

down mode, all instructions are ignored except the

Release from Deep Power-down and Read Elec-

tronic Signature (RES) instruction. Executing this

instruction takes the device out of the Deep Pow-

er-down mode. The instruction can also be used to

read, on Serial Data Output (Q), the 8-bit Electron-

ic Signature of the device.

Except while an Erase, Program or Write Status

Register cycle is in progress, the Release from

Deep Power-down and Read Electronic Signature

(RES) instruction always provides access to the

Electronic Signature of the device, and can be ap-

plied even if the Deep Power-down mode has not

been entered.

Any Release from Deep Power-down and Read

Electronic Signature (RES) instruction while an

Erase, Program or Write Status Register cycle is in

progress, is not decoded, and has no effect on the

cycle that is in progress.

This instruction serves a second purpose. The de-

vice features an 8-bit Electronic Signature, whose

value for the M25P05 is 10h. This can be read us-

ing the Release from Deep Power-down and Read

Electronic Signature (RES) instruction.

The device is first selected by driving Chip Select

(S) Low. The instruction code is followed by a

dummy 3-byte address (A23-A0), each bit being

latched-in on Serial Data Input (D) during the rising

edge of Serial Clock (C). Then, the 8-bit Electronic

Signature, stored in the memory, is shifted out on

Serial Data Output (Q), each bit being shifted out

during the falling edge of Serial Clock (C).

The instruction sequence is shown in Figure 17.

The Release from Deep Power-down and Read

Electronic Signature (RES) instruction is terminat-

ed by driving Chip Select (S) High after the Elec-

tronic Signature has been read at least once.

Sending additional clock cycles on Serial Clock

(C), while Chip Select (S) is driven Low, cause the

Electronic Signature to be output repeatedly.

Once Chip Select (S) is driven High, the device is

put in the Standby mode. The device waits to be

selected, so that it can receive, decode and exe-

cute instructions.

C

D

AI03755C

S

Q

23

2

1

3456789 10

28 29 30 31 32 33 34 35

22 21

3210

36 37 38

765432

0

1

High Impedance

Electronic Signature Out

Instruction

24-Bit Address

0

MSB

Stand-by Mode

Deep Power-down Mode

MSB