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28.6.5
Toggle Bit-2 Flag (DQ2)
The toggle bit-2 flag (DQ2) is a flag that uses the toggle bit function to indicate that the
sector is in the erase-suspended state.
■ Toggle Bit-2 Flag (DQ2)
Table 28.6-11 lists the toggle bit-2 flag state transitions (state change for normal operation) and Table 28.6-
12 lists the toggle bit-2 flag state transitions (state change for abnormal operation).
Table 28.6-11 Toggle Bit-2 Flag State Transitions (State Change for Normal Operation)
Write →
Operating
state
Completed
1 →
DQ2
DATA:2
Table 28.6-12 Toggle Bit-2 Flag State Transitions (State Change for Abnormal Operation)
Operating state
DQ2
*: If the DQ5 outputs "1" (exceed the timing limit), successive reads from a writing or erasing sector cause DQ2
to toggle. DQ2 does not toggle when the successive reads are executed from other sectors.
●
During a sector erase operation
If successive reads are executed during the execution of the chip sector erase algorithm, a flash memory
toggles to output "1" and "0" to addresses alternately at every read access regardless of the location
indicated by the addresses. If successive reads are executed after the chip sector erase algorithm is
completed, the flash memory stops the toggle operation of the bit2 and outputs the read value of the bit2
(DATA: 2) to the location indicated by the address.
Chip/sector
Sector
erase →
erase wait
→ Started
Completed
Toggle →
Toggle
Stop
Write
1
CHAPTER 28 3M-BIT FLASH MEMORY
Sector erase
Sector erase
→ Erase
suspend →
suspend
Restarted
(sector being
(sector being
erased)
erased)
Toggle
Chip/sector erase
*
Sector erase
suspended
(sector not
being erased)
Toggle
DATA:2
573
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