Sector Erase Timer Flag (Dq3) - Fujitsu MB90895 Series Hardware Manual

CHAPTER 19 512 KBIT FLASH MEMORY
19.7.4

Sector Erase Timer Flag (DQ3)

The sector erase timer flag is used to notify during the period of waiting for sector
erasing after the sector erase command has started.
I Sector Erase Timer Flag (DQ3)
Table 19.7-9 "State Transition of Sector Erase Timer Flag (State Change at Normal Operation)"
and Table 19.7-10 "State Transition of Sector Erase Timer Flag (State Change at Abnormal
Operation)" give the state transition of the sector erase timer flag.
Table 19.7-9 State Transition of Sector Erase Timer Flag (State Change at Normal Operation)
Programming
Operating State
→
Completed
→
DQ3 0 DATA3
Table 19.7-10 State Transition of Sector Erase Timer Flag (State Change at Abnormal Operation)
Operating
Programming
State
DQ3
G
At sector erasing
• If a read access is made after starting the sector erase command and it is within a sector
erasing wait period, the sector erasing timer flag (DQ3) outputs 0. If it exceeds the period, the
sector erasing timer flag (DQ3) outputs 1.
• If the sector erasing timer flag (DQ3) is 1, indicating that the automatic algorithm for sector
erasing by the data polling or toggle bit function is in progress (DQ7 = 0; DQ6 produces a
toggle output), sector erasing is performed. If any command other than the sector erasing
suspension is set, it is ignored until sector erasing is terminated.
• If the sector erasing timer flag (DQ3) is 0, flash memory can accept the sector erase
command. To program the sector erase command, check that the sector erasing timer flag
(DQ3) is 0. If the flag is 1, flash memory may not accept the sector erase command of
suspending.
G
At sector erasing suspension
• Read access during sector erasing suspension causes flash memory to output 1, if the read
address is in the sector being erased. Flash memory outputs bit 3 (DATA: 3) for the read value
of the read address when the read address is not the sector being erased.
596
Chip and
Sector Erasing
→
Completed
1
Chip and
Sector Erasing
0 1
Sector Erasing
→
Wait for Sector
Erasing
→
Erasing Suspended
Started (Sector being
Erased)
→ →
0 1 1
Sector Erasing Sector Erasing
→
being
Suspended
Suspended
Resume
(Sector not
(Sector being
being Erased)
Erased)
→
0 0 1 DATA:3