Command interface
M29W320ET, M29W320EB
Status register. A Read/Reset command must be issued to reset the error condition and
return to Read mode.
The Chip Erase Command sets all of the bits in unprotected blocks of the memory to ’1’. All
previous data is lost.
4.10
Block Erase command
The Block Erase command can be used to erase a list of one or more blocks. It sets all of
the bits in the unprotected selected blocks to ’1’. All previous data in the selected blocks is
lost.
Six Bus Write operations are required to select the first block in the list. Each additional
block in the list can be selected by repeating the sixth Bus Write operation using the address
of the additional block. The Block Erase operation starts the Program/Erase Controller after
a time-out period of 50µs after the last Bus Write operation. Once the Program/Erase
Controller starts it is not possible to select any more blocks. Each additional block must
therefore be selected within 50µs of the last block. The 50µs timer restarts when an
additional block is selected. After the sixth Bus Write operation a Bus Read operation will
output the Status register. See the Status register section for details on how to identify if the
Program/Erase Controller has started the Block Erase operation.
If any selected blocks are protected then these are ignored and all the other selected blocks
are erased. If all of the selected blocks are protected the Block Erase operation appears to
start but will terminate within about 100µs, leaving the data unchanged. No error condition is
given when protected blocks are ignored.
During the Block Erase operation the memory will ignore all commands except the Erase
Suspend command and the Read/Reset command which is only accepted during the 50µs
time-out period. Typical block erase times are given in Table 6.
After the Erase operation has started all Bus Read operations will output the Status register
on the Data Inputs/Outputs. See the section on the Status register for more details.
After the Block Erase operation has completed the memory will return to the Read mode,
unless an error has occurred. When an error occurs Bus Read operations will continue to
output the Status register. A Read/Reset command must be issued to reset the error
condition and return to Read mode.
4.11
Erase Suspend command
The Erase Suspend Command may be used to temporarily suspend a Block Erase
operation and return the memory to Read mode. The command requires one Bus Write
operation.
The Program/Erase Controller will suspend within the Erase Suspend Latency time of the
Erase Suspend Command being issued. Once the Program/Erase Controller has stopped
the memory will be set to Read mode and the Erase will be suspended. If the Erase
Suspend command is issued during the period when the memory is waiting for an additional
block (before the Program/Erase Controller starts) then the Erase is suspended immediately
and will start immediately when the Erase Resume Command is issued. It is not possible to
select any further blocks to erase after the Erase Resume.
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