Toggle Bit Flag (Dq6) - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 26 2M BIT FLASH MEMORY

26.5.2 Toggle Bit Flag (DQ6)

Like the data polling flag (DQ7), the toggle bit flag (DQ6) is a flag mainly used to
indicate whether the automatic algorithm is being executed or has ended. In the case
of the toggle bit flag, a toggle bit function is used for that purpose.
I State transitions of the toggle bit flag (DQ6)
❍ State transitions in normal operation
Write
Operation
operation -->
state
completed
Toggle -->
DQ6
DATA: 6
❍ State transitions in operation error mode
Operation Write
state operation
DQ6 Toggle
I Write/chip sector erase operations
In the case of repeated read accesses when the automatic write algorithm and the chip sector
erase algorithm are being executed, the flash memory toggles between output of 1 and 0 in
toggle mode for each read operation independent of addressing. When repeated read accesses
are performed when the automatic write algorithm and chip/sector erase algorithm have ended,
the flash memory stops with the toggle operation of bit 6, and instead outputs bit 6 (DATA: 6) of
the read value for the specified address.
I Sector erase suspend
If read access is performed when a sector erase operation is suspended, the flash memory
outputs "1" when the specified address belongs to the sector being erased. In other cases, bit 6
(DATA: 6) of the read value for the specified address will be output.
Reference:
If, in write operations, the sector to be written is rewrite-protected, toggle operation is
performed for about 2 µs before the operation ends without any data being rewritten.
If, in erase operation, all sectors selected are rewrite-protected, toggle operation is
performed for about 100 µs before the device returns to the read/reset state without any data
being changed.
480
Chip sector Sector
erase --> erase wait
completed --> start
Toggle -->
Toggle
Stop
Chip sector
erase
operation
Toggle
Sector erase
Sector erase -->
suspend -->
erase suspend
resume
(sector being
(sector being
erased)
erased)
Toggle --> 1 1 --> Toggle
Sector erased
Suspend mode
Sector not being
erased
DATA: 6