Toggle Bit Flag (Dq6); Table 25-7 State Transition Of Toggle Bit Flag (State Change At Normal Operation); Table 25-8 State Transition Of Toggle Bit Flag (State Change At Abnormal Operation) - Fujitsu MB90420/5 (A) Series Hardware Manual

25.6.2 Toggle Bit Flag (DQ6)

Like the data polling flag (DQ6), the toggle bit flag is mainly used to notify that the automatic algorithm is
executing or has been completed using the toggle bit function.
n Toggle bit flag (DQ6)
Tables 25-7 and 25-8 gives the state transition of the toggle bit flag.

Table 25-7 State Transition of Toggle Bit Flag (State change at normal operation)

Operating Programming
→ → Completed
State
Toggle
DQ6
→ DATA:6

Table 25-8 State Transition of Toggle Bit Flag (State change at abnormal operation)

Operating State
• At programming or chip sector erasing
When read access is performed continuously during execution of the automatic programming algorithm or
the chip sector erase algorithm, the flash memory outputs 1 and 0 alternately each time a read is
performed (toggle state), irrespective of the address indicated by the address signal. When read access is
performed continuously at completion of the automatic programming algorithm or the chip sector erasing
algorithm, the flash memory stops the bit 6 toggle operation and outputs bit 6 (DATA: 6) of the value read
at the address indicated by the address signal.
• At sector erasing suspension
When read access is performed at the sector erasing suspention, the flash memory outputs 1 when the
address indicated by the address signal belongs to the sector currently being erased. When the address
does not belong to the sector currently being erased, the flash memory outputs bit 6 (DATA: 6) of the value
read at the address indicated by the address signal.
Reference: At programming, when the sector to be programmed is write-protected, toggle operation is
performed for about 2 µs and then ends without changing the data.
At erasing, when the selected sectors are all write-protected, the toggle bit performs the toggle
operation for about 100 µs and then returns to the read/reset state without changing the data.
1-MBIT FLASH MEMORY
Wait for
Chip Sector
Sector
Erasing
Erasing
→ → Completed
→ → Started
Toggle → Stop
Toggle
Programming
DQ6 Toggle
Sector Erasing
Suspend
→ → Resumed
Sector being
Erased
Toggle → 1
Chip Sector Erasing
Toggle
25-13
Sector Erasing Sector Erasing
Suspended being
→ → Resume
Suspended
Sector being Sector not Being
Erased Erased
1 → Toggle
DATA:6