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CHAPTER 20 1M-BIT (128KB) FLASH MEMORY
20.5.2 Toggle Bit Flag (DQ6)
Like the data polling flag, the toggle bit flag (DQ6) uses the toggle bit function to post
that the automatic algorithm is being executed or has terminated.
s Toggle Bit Flag (DQ6)
Table 20.5-5 "Toggle Bit Flag State Transitions (state change for normal operation)" and
Table 20.5-6 "Toggle Bit Flag State Transitions (state change for abnormal operation)" list the state
transitions of the toggle bit flag.
r Write/chip sector erase
Continuous read-access during execution of the automatic write algorithm and chip/sector erase
algorithm causes the flash memory to toggle the 1 or 0 state for every read cycle, regardless of
the value at the address specified by the address signal. Continuous read-access at the end of
the automatic write algorithm and chip/sector erase algorithm causes the flash memory to stop
toggling bit 6 and output bit 6 (DATA: 6) of the read value of the address specified by the
address signal.
r Sector erase suspend
Read-access during a 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 6 (DATA: 6) of the read value at the address specified by the address signal if the address
specified by the address signal does not belong to the sector being erased.
Note:
For a write, if the sector where data is to be written is rewrite-protected, the toggle bit
terminates the toggle operation after approximately 2
s and without any data being
rewritten.
For an erase, if all of the selected sectors are write-protected, the toggle bit performs
toggling for approximately 100
s and then returns to the read/reset state without any data
being rewritten.
Table 20.5-5 Toggle Bit 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)
DQ6
Toggle -->
DATA:6
Toggle -->
Stop
Toggle
Toggle --> 1
1 --> Toggle
DATA:6
Table 20.5-6 Toggle Bit Flag State Transitions (state change for abnormal operation)
Operating state
Write
Chip/sector erase
DQ6
Toggle