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

26.5.3 Timing Limit Excess Flag (DQ5)

The timing limit excess flag (DQ5) is used to indicate when the execution of the
automatic algorithm exceeds the time (internal pulse count) specified in the internal
flash memory.
I State transitions of the timing limit excess flag (DQ5)
❍ State transitions in normal operation
Write
Operation
operation -->
state
completed
DQ5 0 --> DATA: 5
❍ State transitions in operation error mode
Operation Write
state operation
DQ5 1
I Write/chip sector erase operation
If a read access is performed after a writing operation occurs or the chip sector erase automatic
algorithm starts, "0" is output if the specified time (for write/erase operations) is not exceeded,
while "1" is output if this time is exceeded. This operation is independent of whether the
automatic algorithm is being executed or has ended, thus allowing whether a failure has
occurred during a write/erase operation to be determined. If this flag indicates "1" while the
automatic algorithm is still being executed according to the data polling function or toggle bit
function, it can be assumed that a failure during a write operation has occurred.
For example, if there is an attempt to write "1" to a flash memory address whose corresponding
value has already been set to "0", a failure occurs. In this case, the flash memory will be locked,
and the automatic algorithm will not end. As a result, the data polling flag (DQ7) will output that
there is no valid data. The toggle bit flag (DQ6) will continue with the toggle operation until the
time limit is exceeded, and the timing limit excess flag (DQ5) will output "1". This indicates that
the flash memory is not defective, but was used incorrectly. If this state occurs, execute the
reset command.
Chip sector Sector
erase --> erase wait
completed --> start
0 --> 1 0
Chip sector
erase
operation
1
CHAPTER 26 2M BIT FLASH MEMORY
Sector erase
Sector erase -->
suspend -->
erase suspend
resume
(sector being
(sector being
erased)
erased)
0
Sector erased
Suspend mode
Sector not being
erased
0 DATA: 5
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