ACE25AA160GFMLTH datasheet(29/46 Pages) ACE

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ACE25AA160G

Serial NOR Flash Memory 3.0V Multi I/O with 4KB,32KB & 64KB Sector/Block Erase

VER 1.2

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 Figure22. 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.

High Speed Mode(HSM)(A3H)

The High Speed Mode (HSM) command must be executed prior to Dual or Quad I/O commands when

operating at high frequencies (see fR and fC1 in AC Electrical Characteristics). This command allows

pre-charging of internal charge pumps so the voltages required for accessing the flash memory array are

readily available. The command sequence: CS# goes low Sending A3H command Sending 3-dummy

byte CS# goes high. See Figure23. After the HSM command is executed, the device will maintain a

slightly higher standby current (ICC8) than standard SPI operation. The Release from Power-Down or

HSM command (ABH) can be used to return to standard SPI standby current (ICC1). In addition, Write

Enable command (06H) and Power-Down command (B9H) will also release the device from HSM mode

back to standard SPI standby state.

Figure22. Read Identification ID Sequence Diagram

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