256Mb, 512Mb, 1Gb, 2Gb: 3V Embedded Parallel NOR Flash
READ and AUTO SELECT Operations
READ and AUTO SELECT Operations
READ/RESET Command
The READ/RESET (F0h) command returns the device to read mode and resets the errors
in the status register. One or three bus WRITE operations can be used to issue the
READ/RESET command.
To return the device to read mode, this command can be issued between bus WRITE
cycles before the start of a PROGRAM or ERASE operation. If the READ/RESET com-
mand is issued during the timeout of a BLOCK ERASE operation, the device requires up
to 10μs to abort, during which time no valid data can be read.
This command will not abort an ERASE operation while in erase suspend.
READ CFI Command
The READ CFI (98h) command puts the device in read CFI mode and is only valid when
the device is in read array or auto select mode. One bus WRITE cycle is required to issue
the command.
Once in read CFI mode, bus READ operations will output data from the CFI memory
area (Refer to the Common Flash Interface for details). A READ/RESET command must
be issued to return the device to the previous mode (read array or auto select ). A sec-
ond READ/RESET command is required to put the device in read array mode from auto
select mode.
AUTO SELECT Command
At power-up or after a hardware reset, the device is in read mode. It can then be put in
auto select mode by issuing an AUTO SELECT (90h) command. Auto select mode ena-
bles the following device information to be read:
• Electronic signature, which includes manufacturer and device code information as
shown in the Electronic Signature table.
• Block protection, which includes the block protection status and extended memory
block protection indicator, as shown in the Block Protection table.
Electronic signature or block protection information is read by executing a READ opera-
tion with control signals and addresses set, as shown in the Read Electronic Signature
table or the Block Protection table, respectively. In addition, this device information can
be read or set by issuing an AUTO SELECT command.
Auto select mode can be used by the programming equipment to automatically match a
device with the application code to be programmed.
Three consecutive bus WRITE operations are required to issue an AUTO SELECT com-
mand. The device remains in auto select mode until a READ/RESET or READ CFI com-
mand is issued.
The device cannot enter auto select mode when a PROGRAM or ERASE operation is in
progress (RY/BY# LOW). However, auto select mode can be entered if the PROGRAM or
ERASE operation has been suspended by issuing a PROGRAM SUSPEND or ERASE SUS-
PEND command.
PDF: 09005aef849b4b09
m29ew_256mb_2gb.pdf - Rev. B 8/12 EN
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