M29W320ET, M29W320EB
leaving the data unchanged. No error condition is
given when protected blocks are ignored.
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.
During the erase operation the memory will ignore
all commands, including the Erase Suspend com-
mand. It is not possible to issue any command to
abort the operation. Typical chip erase times are
given in Table 6.. All Bus Read operations during
the Chip Erase operation will output the Status
Register on the Data Inputs/Outputs. See the sec-
tion on the Status Register for more details.
After the Chip Erase operation has completed the
memory will return to the Read Mode, unless an
error has occurred. When an error occurs the
memory will continue to output the Status Regis-
ter. A Read/Reset command must be issued to re-
set the error condition and return to Read Mode.
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 Sus-
pend Command being issued. Once the Program/
Erase Controller has stopped the memory will be
set to Read mode and the Erase will be suspend-
ed. If the Erase Suspend command is issued dur-
ing the period when the memory is waiting for an
additional block (before the Program/Erase Con-
troller starts) then the Erase is suspended immedi-
ately 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.
The Chip Erase Command sets all of the bits in un-
protected blocks of the memory to ’1’. All previous
data is lost.
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 Pro-
gram/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 opera-
tion a Bus Read operation will output the Status
Register. See the Status Register section for de-
tails on how to identify if the Program/Erase Con-
troller 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 un-
changed. No error condition is given when protect-
ed blocks are ignored.
During Erase Suspend it is possible to Read and
Program cells in blocks that are not being erased;
both Read and Program operations behave as
normal on these blocks. If any attempt is made to
program in a protected block or in the suspended
block then the Program command is ignored and
the data remains unchanged. The Status Register
is not read and no error condition is given. Read-
ing from blocks that are being erased will output
the Status Register.
It is also possible to issue the Auto Select, Read
CFI Query and Unlock Bypass commands during
an Erase Suspend. The Read/Reset command
must be issued to return the device to Read Array
mode before the Resume command will be ac-
cepted.
During Erase Suspend a Bus Read operation to
the Extended Block will output the Extended Block
data.
Erase Resume Command
The Erase Resume command must be used to re-
start the Program/Erase Controller after an Erase
Suspend. The device must be in Read Array mode
before the Resume command will be accepted. An
erase can be suspended and resumed more than
once.
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.
Enter Extended Block Command
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 Sta-
tus Register for more details.
The M29W320E has an extra 64KByte block (Ex-
tended Block) that can only be accessed using the
Enter Extended Block command. Three Bus write
cycles are required to issue the Extended Block
command. Once the command has been issued
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STMICROELECTRONICS [ ST ]
