Toggle Bit 2 Flag (Dq2) - Fujitsu MB90895 Series Hardware Manual

19.7.5

Toggle Bit 2 Flag (DQ2)

The toggle bit 2 flag (DQ2) is a hardware sequence flag that notifies flash memory that
sector erasing is being suspended using the toggle bit function.
I Toggle Bit Flag (DQ2)
Table 19.7-11 "State Transition of Toggle Bit Flag (State Change at Normal Operation)" and Table
19.7-12 "State Transition of Toggle Bit Flag (State Change at Abnormal Operation)" give the state
transition of the toggle bit flag.
Table 19.7-11 State Transition of Toggle Bit Flag (State Change at Normal Operation)
Programming
Operating State
→
Completed
→
DQ2 1 DATA:2
Table 19.7-12 State Transition of Toggle Bit Flag (State Change at Abnormal Operation)
Operating State
DQ2
*: If the DQ5 flag is 1 (timing limit over), the DQ2 flag performs the toggle operation for continuous reading from the
programming/erasing sector but does not perform the toggle operation for reading from other sectors.
G
At sector erasing
• If a continuous read access is made during the execution of the automatic algorithm for chip /
sector erasing, flash memory toggle-outputs 1 and 0 alternately every reading.
• If a continuous read access is made after the completion of the algorithm for chip/sector
erasing, flash memory outputs bit 2 (DATA: 2) of the read address every reading.
Chip and
Wait for Sector
Sector Erasing
→
Started
→
Completed
→
Toggle Stop Toggle
Programming
1
CHAPTER 19 512 KBIT FLASH MEMORY
Sector Erasing Sector Erasing
→
Erasing Suspended
Suspended Resume Sector
(Sector being being Erased)
Erased)
Toggle Toggle
Chip and Sector Erasing
Sector Erasing
→
being
Suspended
(Sector not
being Erased)
DATA:2
*
597