256Mb: 3V Embedded Parallel NOR Flash
AUTO SELECT Operations
AUTO SELECT Operations
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 or by applying VID to A9.
Auto select mode enables 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.
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.
To enter auto select mode by appling VID to A9, see the Read Electronic Signature table
and the Block Protection table.
Auto select mode is exited by performing a reset. The device returns to read mode un-
less it entered auto select mode after an ERASE SUSPEND or PROGRAM SUSPEND
command, in which case it returns to erase or program suspend mode.
Table 10: Read Electronic Signature
Note 1 applies to entire table
READ Cycle
Manufacturer
Code
Signal
Device Code 1
Device Code 3
Device Code 3 Notes
CE#
L
L
L
L
L
L
L
L
OE#
WE#
H
H
H
H
Address Input, 8-Bit and 16-Bit
A[MAX:10]
A9
X
VID
X
X
VID
X
X
VID
X
X
VID
X
2
A8
A[7:5]
A4
L
L
L
L
X
X
X
X
A[3:1]
L
L
H
H
PDF: 09005aef84bd3b68
m29w_256mb.pdf - Rev. C 7/13 EN
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