Sector Erase Timer Flag (Dq3); Table 25-11 State Transition Of Sector Erase Timer Flag (State Change At Normal Operation); Table 25-12 State Transition Of Sector Erase Timer Flag (State Change At Abnormal Operation) - Fujitsu MB90420/5 (A) Series Hardware Manual

25.6.4 Sector Erase Timer Flag (DQ3)

The sector erase time flag is used to notify during the period of waiting for sector erasing after the sector
erase command has started.
n Sector erase timer flag (DQ3)
Tables 25-11 and 25-12 gives the state transition of the sector erase timer flag.

Table 25-11 State Transition of Sector Erase Timer Flag (State change at normal operation)

Operating Programming
→ → Completed
State
0 → DATA:3
DQ3

Table 25-12 State Transition of Sector Erase Timer Flag (State change at abnormal operation)

Operating State
n At sector erasing
When read access is performed after the sector erase command is started, the flash memory outputs 0
during the wait period for sector erasing, irrespective of the address indicated by the address signal of the
sector to which the command is issued; it outputs 1 when the wait period for sector erasing is exceeded.
When the erasing algorithm is currently being executed by the data polling function or toggle bit function,
with this flag 1, it indicates that an internally controlled erasing has already started. The next sector erase
code write or command other than the erasing suspended command is ignored until the current erasing
completes.
When this flag is 0, the flash memory accepts writing the additional sector erase code. To check, it is best to
check the state of this flag before writing the subsequent sector erase code. If the second check on this flag
shows that this flag is 1, there is a possibility that the additional sector erase code is not accepted.
n 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 the value of bit 3 (DATA: 3)
at the address specified by the address signal, if the address specified by the signal address does not
belong to the sector being erased.
1-MBIT FLASH MEMORY
Wait for
Chip Sector
Sector
Erasing
Erasing
→ → Completed
→ → Started
0 → 1
1
Programming
DQ3 0
Sector Erasing
Suspend
→ → Resumed
Sector being
Erased
1 → 0
Chip Sector Erasing
25-15
Sector Erasing Sector Erasing
Suspended
→ → Resume
Suspended
Sector being Sector not Being
Erased
0 → 1
1
being
Erased
DATA:3