ACE25AC400GL

SPI NOR FLASH

VER 1.1

13

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 device is first selected by driving CS# to 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, being shifted out on Serial Data

Output, each bit being shifted out during the falling edge of Serial Clock. The command sequence is

shown in Figure12. The Read Identification (RDID) command is terminated by driving CS# to high at any

time during data output. After CS# is driven high, the device returns to Standby Mode and awaits for new

command.

Figure12. Read Identification ID Sequence Diagram