Toggle Bit 2 Flag (Dq2) - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 25 3M-BIT FLASH MEMORY
25.5.5

Toggle Bit 2 Flag (DQ2)

The toggle bit 2 flag (DQ2) is a flag that indicates that it is the sector erase suspend
period with the toggle bit function.
Transition State of Toggle Bit 2 Flag (DQ2)
State change in normal operation
Operation Programming
→
State
Completion
→
DQ2
1 DATA:2
State change in Abnormal operation
Operation State
DQ7
*: When DQ5 is "1" (excess of the time limit), DQ2 performs toggle operation to continuous reading to the sector in the
middle of writing/erasing. And no toggle operation is performed to reading to any other sectors.
When Sector Deletion Operate
If you execute read-access sequentially while executing the chip/sector erase algorithm, the flash memory
outputs the toggle state outputting "1" and "0" alternately per read, regardless of the specified address.
If you execute read-access sequentially after the chip/sector erase algorithm ends, the flash memory
terminates the bit 2 toggle output and outputs bit 2 (DATA: 2) of the read value of the specified address.
Sector Erasing being Suspended
If you execute read-access sequentially when the sector erase suspends, the flash memory outputs the
toggle state outputting "1" and "0" alternately if the specified address belongs to the sector being erased. If
it does not belong to the sector being erased, it outputs the bit 2 (DATA: 2) of the read value of the
specified address.
Additionally, during the sector erase suspend write, if you execute read-access sequentially from the sector
not being in the erase suspend," 1" is output.
DQ2 and DQ6 are used together to detect if the state is in the erase suspend.
(DQ2 performs toggle-operation but DQ6 does not.)
In addition, DQ2 is used to detect the deleted sector. When the deletion operates, DQ2 performs toggle-
operation if it is the read-access from the sector being erased.
Note:
During erasing, if all the selected sectors are rewrite-protected, toggle bit 2 performs toggle-
operation for about 100 µs, and then it goes back to the read/reset state without rewriting the data.
576
Chip and Sector erasing
→
sector erasing
wait start
→
Completion
→
Toggle
Toggle Stop
Programming operation
1
Sector Erasing Sector Erasing
→
being Suspended
Temporary
→
Restart
deletion stop
Sector being Sector being
erased erased
Toggle Toggle
Chip sector erase operation
Sector Erasing
Temporary
Sector not being
deleted
DATA:2
*
1