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Figure 17.4-2 Chip Erasing Sequence with Using Chip Erase Command
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Temporary Stop Erase
The temporary stop erase command temporarily stops the automatic algorithm in flash memory when the
user is erasing the data of a sector, thereby making it possible to write data to and read data from the other
sectors. This command is valid only during the sector erase operation, and ignored during chip erase and
write operations. The temporary stop erase command (B0
that includes the sector erase time-out period after a sector erase command (30
command is entered within the time-out period, time-out ends immediately and the erase operation is
suspended. The erase operation is restarted when a restart erase command was written. Temporary stop
erase and restart erase commands can be entered with any addresses.
When a temporary stop erase command is entered during sector erase operation, the flash memory needs a
maximum of 20 µs to stop the erase operation. When flash memory enters temporary erase stop mode, a
ready/busy signal and bit7 output "1", and bit6 stops to toggle. For checking whether the erase operation
has stopped, enter the address of the sector whose data is being erased and read the values of bit6 and bit7.
At this time, another temporary stop erase command entry is ignored. When the erase operation stops,
flash memory enters the temporary erase stop and read mode. Data reading is enabled in this mode for
sectors that are not subject to temporary erase stop. Other than that, there is no difference from the
standard read operation. In this mode, bit2 toggles for consecutive reading operations from sectors subject
to temporary erase stop (see "■Hardware Sequence Flag" in section "17.5 Automatic Algorithm Execution
Status").
After the temporary erase stop and read mode is entered, the user can write to flash memory by writing a
write command sequence. The write mode in this case is the temporary erase stop and write mode. In this
mode, data write operations become valid for sectors that are not subject to temporary erase stop. Other
than that, there is no difference from the standard byte writing operation. In this mode, bit2 toggles for
consecutive reading operations from sectors that are subject to temporary erase stop. The temporary erase
stop bit (bit6) can be used to detect this operation.
Note that bit6 can be read from any addresses, but bit7 must be read from write addresses. To restart the
sector erase operation, a restart erase command (30
entry is ignored in this point. On the other hand, a temporary stop erase command can be entered after
flash memory restarts the erase operation.
Erase starts
Chip erase/sector erase
command sequence
Data polling of the device or
toggle bit completed
Write ends
) must be entered. Another restart erase command
H
CHAPTER 17 FLASH MEMORY
) is effective only during sector erase operation
H
) is issued. When this
H
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