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CHAPTER 23 512K / 1024K BIT FLASH MEMORY
23.5.3
Time limit Exceeded Flag (DQ5)
The time limit exceeded flag indicates that the automatic algorithm execution time has
exceeded the time defined within the flash memory (i.e., internal pulse count). Table
23.5-5 shows the transition of the time limit exceeded flag status.
■ When the Write Operation or Chip/Sector Deletion Operation is Executed.
When the read/access is executed after starting the write or chip/sector deletion automatic algorithm, this
flag is set to "0" if the execution time is within the defined time (required for writing/deletion), or it outputs
"1" if this execution time exceeds the defined time. This is not related to the state in which the automatic
algorithm is being executed or has been terminated, so it can be determined whether the write/delete has
succeeded or failed. Thus, when this flag is set to "1", it indicates that the write operation has failed if the
automatic algorithm is being performed by the data polling function or toggle bit function.
For example, a fail occurs if an attempt is made to write "1" to the flash memory with "0" written. In this
case, the flash memory is locked and the automatic algorithm is not terminated. Therefore, no valid data is
set in data polling flag (DQ7). The toggle bit flag (DQ6) does not stop the toggle operation, so the
execution time exceeds the time limit. Then, the time limit exceeded flag (DQ5) outputs "1". This event
indicates that the flash memory has not been correctly used, but does not indicate that the flash memory is
not good. If this event occurs, the reset command should be executed.
Table 23.5-5 Transition of the Time Limit Exceeded Flag Status
- Status transition during normal operation
Operating
Write operation
status
--> Completion
DQ5
0-->DATA:5
- Status transition during abnormal operation
Write operation
Operating status
DQ5
598
Chip/sector
Sector deletion
deletion
wait-->Start
-->Completion
0-->1
0
Chip/sector deletion operation
1
Sector deletion
-->Deletion
temporary stop
(Sector being
deleted)
0
1
Sector deletion
During the sector
temporary stop
deletion temporary
-->Restart
stop (Sector not
(Sector being
being deleted)
deleted)
DATA:5
0
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