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CHAPTER 22 DUAL OPERATION FLASH MEMORY
22.6 Check the Execution State of Automatic Algorithm
22.6.1
Data Polling Flag (DQ7)
The data polling flag (DQ7) is a hardware sequence flag which mainly used to notify that
the automatic algorithm is executing or has been completed using the data polling
function.
■ Data Polling Flag (DQ7)
Table 22.6-3 and Table 22.6-4 give the state transition of the data polling flag.
Table 22.6-3 State Transition of Data Polling Flag (State Change at Normal Operation)
Programming
Operating State
→
Completed
DQ7
DQ7
DATA:7
Table 22.6-4 State Transition of Data Polling (State Change at Abnormal Operation)
Operating State
DQ7
●
At programming
• Read access during execution of the auto-programming algorithm causes flash memory to output the
reversed data of bit7 last written.
• Read access at the end of the auto-programming algorithm causes flash memory to output the read value
of bit7 at the address to which read access was performed.
●
At chip/sector erasing
• During executing chip and sector erasing automatic algorithms, when read access is made to the currently
being erasing sector, bit7 of flash memory outputs "0". When chip erasing/sector erasing is terminated,
bit7 of flash memory outputs "1".
●
At sector erasing suspension
• Read access during sector erasing suspension causes flash memory to output "1" if the address specified
by the address signal belongs to the sector being erased. Flash memory outputs bit7 (DATA: 7) of the
read value at the address specified by the signal address if the address specified by the address signal
does not belong to the sector being erased.
• Referring the data polling flag (DQ7) together with the toggle bit flag (DQ6) permits a decision on
whether flash memory is in the erase suspended state and which sector is being erased.
496
Chip and
Sector Erasing
→
Completed
→
→
1
0
Programming
FUJITSU MICROELECTRONICS LIMITED
Sector Erasing
→
Wait for Sector
Erasing
→
Erasing
Suspended
Started
(Sector being
Erased)
→
0
0
DQ7
MB90335 Series
Sector Erasing
→
Suspended
Resume
(Sector being
Erased)
→
1
0
1
Chip and Sector Erasing
0
CM44-10137-6E
Sector Erasing
being
Suspended
(Sector not
being Erased)
DATA:7
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