Timing Limit Over Flag (Dq5) - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 25 3M-BIT FLASH MEMORY
25.5.3

Timing Limit Over Flag (DQ5)

The timing limit excess flag (DQ5) is a flag that indicates that the automatic algorithm
execution is over the predefined time (internal pulse frequency) in the flash memory.
Transition State of Timing Limit Over Flag (DQ5)
State change in normal operation
Operation Programming
→
State
Completion
→
DQ5
0 DATA:5
State change in Abnormal operation
Operation State
DQ5
When Writing/chip Sector is Deleted
If you execute read-access after starting the write or the chip/sector erase automatic algorithms, the flash
memory outputs "0" if it is within the predefined time (time necessary for write/erase) and "1" if it is over
the predefined time. As this flag is irrelevant to the state of the automatic algorithm, you can judge whether
the write/erase algorithm was successfully executed or not. In other words, the automatic algorithm is still
operating by the data polling or toggle bit functions when this flag outputs "1", you can recognize that
writing was failed.
For example, if you write "1" into the flash memory address to which "0" is already written, the operation
fails. In this case, the flash memory is locked and the automatic algorithm does not end. In rare cases, it
ends normally as if "1" was written to the address. Therefore, an effective data is not output from the data
polling flag (DQ7). Also, the toggle bit flag (DQ6) does not terminate the toggle operation, and the timing
limit excess flag (DQ5) outputs "1" overrunning the time limit. This state means that the flash memory does
not have any defect, but it was not used properly. Be sure to execute the reset command if this state
appears.
574
Chip and sector Sector erasing
erasing
wait
→
Completion
→
0 1
Programming operation
1
Sector Erasing
→ →
start Temporary
deletion stop
Sector being
erased
0 0
Chip sector deletion operation
1
Sector Erasing Sector Erasing
being Suspended Temporary
→
Sector not being
Restart
deleted
Sector being
erased
0 DATA:5