3.3V Uniform Sector

Standard and Dual Serial Flash

GD25D40C/20C

21

Mode. The Deep Power-Down (DP) command is entered by driving CS# low, followed by the command code on SI. CS#

must be driven low for the entire duration of the sequence.

The Deep Power-Down command sequence: CS# goes low  sending Deep Power-Down command  CS# goes

high. The command sequence is shown in Figure13. CS# must be driven high after the eighth bit of the command code has

been latched in; otherwise the Deep Power-Down (DP) command is not executed. As soon as CS# is driven high, it requires

Down (DP) command, while an Erase, Program or Write cycle is in progress, is rejected without having any effects on the

cycle that is in progress.

Figure13. Deep Power-Down Sequence Diagram

7.14.

Release from Deep Power-Down / Read Device ID (ABH)

The Release from Power-Down and Read Device ID command is a multi-purpose command, which can be used to

release the device from the Power-Down state or obtain the devices electronic identification (ID) number.

When used to release the device from the Power-Down state, the command is issued by driving the CS# pin low,

shifting the instruction code

“ABH” and driving CS# high as shown in Figure14. Release from Power-Down will take the

When used only to obtain the Device ID while not in the Power-Down state, the command is initiated by driving the

CS# pin low and shifting the instruction code

“ABH” followed by 3-dummy byte. The Device ID bits are then shifted out on

the falling edge of SCLK with most significant bit (MSB) first as shown in Figure15. The Device ID value for the

GD25D40C/20C is listed in Manufacturer and Device Identification table. The Device ID can be read continuously. The

command is completed by driving CS# high.

When used to release the device from the Power-Down state and obtain the Device ID, the command is the same

as previously described, and shown in Figure15, except that after CS# is driven high it must remain high for a time

command will be accepted. If the Release from Power-Down and Read Device ID command is issued while an Erase,

Program or Write cycle is in process (when WIP equal 1) the command is ignored and will not have any effects on the

current cycle.

Figure14. Release Power-Down Sequence Diagram

Command

0

1

2

3

4

5

6

7

B9H

CS#

SCLK

SI

Deep Power-down mode

Command

0

1

2

3

4

5

6

7

ABH

CS#

SCLK

SI

RES1

Stand-by mode

Deep Power-down mode

t