Toggle Bit Flag (Dq6) - Fujitsu MB90390 Series Hardware Manual

28.6.2

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.
■ Toggle Bit Flag (DQ6)
Table 28.6-5 lists the toggle bit flag state transitions (state change for normal operation) and Table 28.6-6
lists the toggle bit flag state transitions (state change for abnormal operation).
Table 28.6-5 Toggle Bit Flag State Transitions (State Change for Normal Operation)
Write →
Operating
state Completed
Toggle →
DQ6
DATA:6
Table 28.6-6 Toggle Bit Flag State Transitions (State Change for Abnormal Operation)
Operating state
●
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 bit6 and output bit6 (DATA: 6) of
the read value of the address specified by the address signal.
●
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 bit6 (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 2μs without any data being rewritten. For an erase, if all of the
selected sectors are write-protected, the toggle bit performs toggling for approximately 100μs and
then returns to the read/reset state without any data being rewritten.
Chip/sector Sector
erase →
erase wait
→ Started
Completed
Toggle →
Toggle
Stop
Write
DQ6 Toggle
CHAPTER 28 3M-BIT FLASH MEMORY
Sector erase Sector erase
→ Erase suspend →
suspend Restarted
(sector being (sector being
erased) erased)
Toggle → 1 1 → Toggle
Chip/sector erase
Toggle
Sector erase
suspended
(sector not
being erased)
DATA:6
569