256Mb, 512Mb, 1Gb, 2Gb: 3V Embedded Parallel NOR Flash
Program Operations
Program Operations
PROGRAM Command
The PROGRAM (A0h) command can be used to program a value to one address in the
memory array. The command requires four bus WRITE operations, and the final WRITE
operation latches the address and data in the internal state machine and starts the pro-
gram/erase controller. After programming has started, bus READ operations output the
status register content.
Programming can be suspended and then resumed by issuing a PROGRAM SUSPEND
command and a PROGRAM RESUME command, respectively.
If the address falls in a protected block, the PROGRAM command is ignored, and the
data remains unchanged. The status register is not read, and no error condition is given.
After the PROGRAM operation has completed, the device returns to read mode, unless
an error has occurred. When an error occurs, bus READ operations to the device contin-
ue to output the status register. A READ/RESET command must be issued to reset the
error condition and return the device to read mode.
The PROGRAM command cannot change a bit set to 0 back to 1, and an attempt to do
so is masked during a PROGRAM operation. Instead, an ERASE command must be used
to set all bits in one memory block or in the entire memory from 0 to 1.
The PROGRAM operation is aborted by performing a reset or by powering-down the de-
vice. In this case, data integrity cannot be ensured, and it is recommended that the
words or bytes that were aborted be reprogrammed.
UNLOCK BYPASS PROGRAM Command
When the device is in unlock bypass mode, the UNLOCK BYPASS PROGRAM (A0h)
command can be used to program one address in the memory array. The command re-
quires two bus WRITE operations instead of four required by a standard PROGRAM
command; the final WRITE operation latches the address and data and starts the pro-
gram/erase controller (The standard PROGRAM command requires four bus WRITE op-
erations). The PROGRAM operation using the UNLOCK BYPASS PROGRAM command
behaves identically to the PROGRAM operation using the PROGRAM command. The
operation cannot be aborted. A bus READ operation to the memory outputs the status
register.
WRITE TO BUFFER PROGRAM Command
The WRITE TO BUFFER PROGRAM (25h) command makes use of the program buffer to
speed up programming and dramatically reduces system programming time compared
to the standard non-buffered PROGRAM command. 256Mb through 2Gb devices sup-
port a 512-word maximum program buffer.
When issuing a WRITE TO BUFFER PROGRAM command, V
PP
/WP# can be held HIGH
or raised to V
PPH
. Also, it can be held LOW if the block is not the lowest or highest block,
depending on the part number.
The following successive steps are required to issue the WRITE TO BUFFER PROGRAM
command:
PDF: 09005aef849b4b09
m29ew_256mb_2gb.pdf - Rev. B 8/12 EN
29
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