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CHAPTER 20 1M-BIT (128KB) FLASH MEMORY
20.5.4 Sector Erase Timer Flag (DQ3)
The sector erase timer flag (DQ3) is used to post whether the automatic algorithm is
being executed during the sector erase wait period after the Sector Erase command
has been started.
s Sector Erase Timer Flag (DQ3)
Table 20.5-9 "Sector Erase Timer Flag State Transitions (state change for normal operation)"
and
Table 20.5-10 "Sector Erase Timer Flag State Transitions (state change for abnormal
operation)" list the state transitions of the sector erase timer flag.
r Sector erase
Read-access after the Sector Erase command has been started causes the flash memory to
output 0 if the automatic algorithm is being executed during the sector erase wait period,
regardless of the value at the address specified by the address signal of the sector that issued
the command. The flash memory outputs 1 if the sector erase wait period has been exceeded.
When the data polling function or toggle bit function indicates that the erase algorithm is being
executed, internally controlled erase has already started if this flag is 1. Continuous write of the
sector erase codes or commands other than the Sector Erase Suspend command will be
ignored until erase is terminated.
If this flag is 0, the flash memory will accept write of additional sector erase codes. To confirm
this, it is recommended that the state of this flag be checked before continuing to write sector
erase codes. If this flag is 1 after the second state check, it is possible that additional sector
erase codes may not be accepted.
r Sector erase
Read-access during execution of sector erase suspend causes the flash memory to output 1 if
the address specified by the address signal belongs to the sector being erased.
The flash
memory outputs bit 3 (DATA: 3) of the read value of the address specified by the address
signal if the address specified by the address signal does not belong to the sector being erased.
Table 20.5-9 Sector Erase Timer Flag State Transitions (state change for normal operation)
Operating
state
Write -->
Completed
Chip/sector
erase -->
Completed
Sector erase
wait -->
Started
Sector erase
--> Erase
suspend
(sector being
erased)
Sector erase
suspend -->
Restarted
(sector being
erased)
Sector erase
suspended
(sector not
being erased)
DQ3
0 --> DATA:3
1
0 --> 1
1 --> 0
0 --> 1
DATA:3
Table 20.5-10 Sector Erase Timer Flag State Transitions (state change for abnormal
operation)
Operating state
Write
Chip/sector erase
DQ3
0
1