GD25WD20C datasheet(22/49 Pages) GIGADEVICE

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Uniform Sector

Standard and Dual Serial Flash

GD25WD40C/20C

7.13.

Deep Power-Down (DP) (B9H)

Executing the Deep Power-Down (DP) command is the only way to enter the lowest consumption mode (the Deep

Power-Down Mode). Unlike deselecting the device by driving CS# high, or entering into the Standby Mode (if there is no

internal cycle currently in progress), the Deep Power-Down Mode provides an extra software protection mechanism while

the device is not in active use. The only access to this mode is by executing the Deep Power-Down (DP) command. Since

in the Deep Power-Down mode, the device ignores all Write, Program and Erase commands. Once the device is in the

Deep Power-Down Mode, all commands are ignored except the Release from Deep Power-Down and Read Device ID (RDI)

command. This releases the device from this mode. The Release from Deep Power-Down and Read Device ID (RDI)

command also allows the Device ID of the device to be output on SO.

The Deep Power-Down Mode automatically stops at Power-Down, and the device always Power-Up in the Standby

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

a delay of tDP before the supply current is reduced to ICC2 and the Deep Power-Down Mode is entered. Any Deep Power-

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

time duration of tRES1 (See AC Characteristics) before the device will resume normal operation and other c omm and are

accepted. The CS# pin must keep high during the tRES1 time duration.

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

GD25WD40C/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

duration of tRES2 (See AC Characteristics). After this time duration the device will resume normal operation and other

Command

B9H

CS#

SCLK

tDP

Stand-by mode Deep Power-down mode

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