ACE25C320G Datasheet, PDF (25/37 Pages) ACE Technology Co., LTD. – Uniform SECTOR Dual and Quad Serial Flash

ACE25C320G
Uniform SECTOR Dual and Quad Serial Flash
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# 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 Figure28. The Read Identification (RDID) command is terminated by driving
CS# to high at any time during data output. When CS# is driven high, the device is put in the Standby
Mode. Once in the Standby Mode, the device waits to be selected, so that it can receive, decode and
execute commands.
Figure 23. Read Identification ID Sequence Diagram
Continuous Read Mode Reset (CRMR) (FFH)
The Dual/Quad I/O Fast Read operations, “Continuous Read Mode” bits (M7-0) are implemented to
further reduce command overhead. By setting the (M7-0) to AXH, the next Dual/Quad I/O Fast Read
operations do not require the BBH/EBH/E7H command code.
Because the ACE25C320G has no hardware reset pin, so if Continuous Read Mode bits are set to
“AXH”, the ACE25C320G will not recognize any standard SPI commands. So Continuous Read Mode
Reset command will release the Continuous Read Mode from the “AXH” state and allow standard SPI
command to be recognized. The command sequence is show in Figure24.
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