AT25DF021 datasheet(27/41 Pages) ATMEL

27 / 41 page

3677D–DFLASH–04/09

AT25DF021

Figure 12-1. Read Manufacturer and Device ID

12.2 Deep Power-Down

During normal operation, the device will be placed in the standby mode to consume less power

as long as the CS pin remains deasserted and no internal operation is in progress. The Deep

Power-Down command offers the ability to place the device into an even lower power consump-

tion state called the Deep Power-Down mode.

When the device is in the Deep Power-Down mode, all commands including the Read Status

command. Since all commands will be ignored, the mode can be used as an extra protection

mechanism against program and erase operations.

Entering the Deep Power-Down mode is accomplished by simply asserting the CS pin, clocking

in the opcode of B9h, and then deasserting the CS pin. Any additional data clocked into the

device after the opcode will be ignored. When the CS pin is deasserted, the device will enter the

Deep Power-Down mode within the maximum time of tEDPD.

The complete opcode must be clocked in before the CS pin is deasserted, and the CS pin must

be deasserted on an even byte boundary (multiples of eight bits); otherwise, the device will abort

the operation and return to the standby mode once the CS pin is deasserted. In addition, the

device will default to the standby mode after a power-cycle.

The Deep Power-Down command will be ignored if an internally self-timed operation such as a

program or erase cycle is in progress. The Deep Power-Down command must be reissued after

the internally self-timed operation has been completed in order for the device to enter the Deep

Power-Down mode.

SCK

9Fh

OPCODE

1Fh

43h

00h

MANUFACTURER ID

DEVICE ID

BYTE1

DEVICE ID

BYTE2

EXTENDED

DEVICE

INFORMATION

STRING LENGTH

HIGH-IMPEDANCE

Note: Each transition

shown for SI and SO represents one byte (8 bits)

AT25DF021 Folha de dados(PDF) 27 Page - ATMEL Corporation