Command interface
M29W800DT, M29W800DB
4.9
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 (refer to
Table 6 for value) 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.
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. Reading 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 accepted.
4.10
4.11
Erase Resume command
The Erase Resume command must be used to restart the program/erase controller from
erase suspend. An erase can be suspended and resumed more than once.
Read CFI Query command
The Read CFI Query command is used to read data from the common flash interface (CFI)
memory area. This command is valid when the device is in the read array mode, or when the
device is in auto select mode.
One bus write cycle is required to issue the Read CFI Query command. Once the command
is issued subsequent bus read operations read from the common flash interface memory
area.
The Read/Reset command must be issued to return the device to the previous mode (read
array mode or auto select mode). A second Read/Reset command would be needed if the
device is to be put in the read array mode from auto select mode.
See Appendix B: Common flash interface (CFI), Table 22, Table 23, Table 24, Table 25,
Table 26 and Table 27 for details on the information contained in the common flash interface
(CFI) memory area.
4.12
Block Protect and Chip Unprotect commands
Each block can be separately protected against accidental program or erase. The whole
chip can be unprotected to allow the data inside the blocks to be changed.
Block protect and chip unprotect operations are described in Appendix C: Block protection.
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