Timing Limit Over Flag (Dq5) - Fujitsu MB90335 Series Hardware Manual

MB90335 Series
22.6.3

Timing Limit Over Flag (DQ5)

The timing limit over flag (DQ5) is a hardware sequence flag that notifies flash memory
that the execution of the automatic algorithm has exceeded a prescribed time (the time
required for programming/erasing).
■ Timing Limit Over Flag (DQ5)
Table 22.6-7 and Table 22.6-8 give the state transition of the timing limit over flag.
Table 22.6-7 State Transition of Timing Limit Over Flag (State Change at Normal Operation)
Programming
→
Operating State
Completed
→
DQ5 0
Table 22.6-8 State Transition of Timing Limit Over Flag (State Change at Abnormal Operation)
Operating State
DQ5
●
At programming and chip/sector erasing
• If a read access is made after starting the automatic algorithm for programming or chip /sector erasing
and it is within a prescribed time (the time required for programming/erasing), the timing limit over flag
(DQ5) outputs "0". If it exceeds the prescribed time, the timing limit over flag (DQ5) outputs "1".
• The timing limit over flag (DQ5) can be used to identify the success or failure of programming/erasing,
regardless of whether the automatic algorithm is in progress or terminated. If the automatic algorithm by
the data polling or the toggle bit function is in execution when the timing limit over flag (DQ5) outputs
1, programming can be identified as a failure.
• For example, the flash memory is locked when it tries to write "1" at the flash memory address where
"0" is written, an automatic algorithm doesn't end, and effective data is not output from data polling flag
(DQ7). Therefore, no valid data is output from the data polling flag (DQ7). Also, the toggle bit flag
(DQ6) does not stop the toggle operation and exceeds the time limit, causing the timing limit over flag
(DQ5) to output "1". This state means that the flash memory is not being used correctly; it does not
mean that the flash memory is faulty. When this state occurs, execute the reset command.
CM44-10137-6E
Chip and
Sector Erasing
→
Completed
→
DATA:5 0 1
FUJITSU MICROELECTRONICS LIMITED
CHAPTER 22 DUAL OPERATION FLASH MEMORY
22.6 Check the Execution State of Automatic Algorithm
Sector Erasing
→
Wait for Sector
Erasing
→
Erasing Suspended
Started (Sector being
Erased)
0 0
Programming
1
Sector Erasing Sector Erasing
→
being
Suspended
Suspended
Resume
(Sector not
(Sector being
being Erased)
Erased)
0 DATA:5
Chip and Sector Erasing
1
499