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CHAPTER 19 512K-BIT (64 KB) FLASH MEMORY
19.5.3 Time Limit Exceeded Flag (DQ5)
The time limit exceeded flag (DQ5) indicates that the automatic algorithm execution
time has exceeded the time defined within the flash memory (i.e., internal pulse count).
"Transition of the Time Limit Exceeded Flag Status " shows the transition of the time
limit exceeded flag status.
s When the Write Operation or Chip/Sector Erase Operation is Executed.
If read access is made after the automatic write algorithm or chip/sector erase algorithm is
activated, the timing limit exceeded flag (DQ5) outputs "0" if the execution time is within the
defined time (time required for write/erase operation), and "1" if the defined time has passed.
DQ5 can determine whether the write/erase operation is successful irrespective of whether the
automatic algorithm is being executed or has been completed. When DQ5 outputs "1", it can be
assumed that the write operation has failed if the automatic algorithm is being performed by the
data polling function or toggle bit function.
For example, if an attempt is made to write "1" to the flash memory bit that contains "0", the
flash memory is locked, the automatic algorithm does not terminate, and thus the data polling
flag (DQ7) cannot output valid data.
The toggle bit flag (DQ6) does not stop its toggle
operation, exceeding the time limit and DQ5 outputs "1". "1" output from DQ5 does not indicate
that the flash memory is defective. Rather, it indicates that the flash memory was not used
correctly, so you need to execute the reset command.
of the Time Limit Exceeded Flag Status " are extracted from
Table 19.5-2 "Hardware Sequence
Flag Function List ".
Table 19.5-7 Transition of the Time Limit Exceeded Flag Status - Status transition during normal
operation
Operating
status
Write operation
-->Completion
Chip/sector
erase
-->Completion
Sector erase
wait
--> Start
Sector erase
-->Erase
suspend
(Sector being
erased)
Sector erase
suspend
-->Restart
(Sector being
erased)
During the
sector erase
suspend
(Sector not
being erased)
DQ5
0-->DATA:5
0-->1
0
DATA:6
Table 19.5-8 Transition of the Time Limit Exceeded Flag Status - Status transition during
abnormal operation
Operating status
Write operation
Chip/sector erase operation
DQ5
1