Uniform Sector

Standard and Dual Serial Flash

GD25WD80C

23

7.16.

Read Identification (RDID) (9FH)

The Read Identification (RDID) command allows the 8-bit manufacturer identification to be read, followed by two bytes

of device identification. The device identification indicates the memory type in the first byte, and the memory capacity of the

device in the second byte. Any Read Identification (RDID) command while an Erase or Program cycle is in progress is not

decoded, and has no effect on the cycle that is in progress. The Read Identification (RDID) command should not be issued

while the device is in Deep Power-Down Mode.

The device is first selected by driving CS# low. Then, the 8-bit command code for the command is shifted in. This is

followed by the 24-bit device identification, stored in the memory. Each bit is shifted out on the falling edge of Serial Clock.

The command sequence is shown in Figure17. The Read Identification (RDID) command is terminated by driving CS# high

at any time during data output. When CS# is driven high, the device is in the Standby Mode. Once in the Standby Mode,

the device waits to be selected, so that it can receive, decode and execute commands.

Figure17. Read Identification ID Sequence Diagram

0

1

2

3

4

5

6

7

CS#

SCLK

SI

SO

8

9 10

MSB

18 19 20 21

17

6

5

4

3

2

1

0

22 23

16

26 27 28 29

25

30 31

24

7

Capacity

JDID7-JDID0

CS#

SCLK

SI

SO

MSB

Memory Type

JDID15-JDID8

6

5

4

3

2

1

0

7

11 12 13 14 15

9FH

6

5

4

3

2

1

0

7

Manufacturer ID

MSB

Command