GD25Q21 datasheet(30/49 Pages) ELM

30 / 49 page

Rev.1.1

49 -

http://www.elm-tech.com

GD25Q21BxIGx Uniform Sector Dual and Quad Serial Flash

7.21. Deep Power-Down (DP) (B9H)

Executing the Deep Power-Down (DP) command is the only way to put the device in the lowest consumption

mode (the Deep Power-Down Mode). It can also be used as an extra software protection mechanism, while

the device is not in active use, since in this mode, the device ignores all Write, Program and Erase commands.

Driving CS# high deselects the device, and puts the device in the Standby Mode (if there is no internal cycle

currently in progress). But this mode is not the Deep Power-Down Mode. The Deep Power-Down Mode

can only be entered by executing the Deep Power-Down (DP) command. Once the device has entered 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 Figure25. 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.

Figure 25. Deep Power-Down Sequence Diagram

Command

0 1 2 3 4 5 6 7

B9H

CS#

SCLK

tDP

Stand-by mode Deep Power-down mode

GD25Q21 Datasheet(PDF) 30 Page - ELM Electronics