C.5.3 Exceeded timing limits flag (DQ5)
Exceeded timing limits flag is used to indicate whether Automatic Algorithm has executed beyond the time
(internal pulse count) specified in the flash memory. Table C.5.3a shows status change of the exceeded
timing limits flag.
•
Programming, Chip and Sector Erase
An attempt to read access after programming or chip/sector erase operation will output "0" to DQ5 if
Automatic Algorithm has executed within the time (internal pulse count) specified in the flash memory. If
it is beyond the limit, "1" will be output to DQ5. With irrespective of he Automatic Algorithm operation
status, It is used to determine whether the program/erase operation has suceeded. Thus, when "1" is
read, it shows that programming or erasing operation is failed if Automatic Algorithm is regarded as still
being executed by data polling function or toggle bit function.
For an example, If the user tries to write "1" to the flash memory address where "0" is written, a failure
will occur. In this case, flash memory will be locked and Automatic Algorithm will not be completed.
Consequently, valid data will not be outputted from the data polling flag (DQ7). In the case of toggle bit
flag (DQ6), the toggle operation on bit 6 will not stopped and bit 5 output "1" to the exceeded timing
limits flag (DQ5). It means that the flash memory is not defective and it has been used incorrectly. The
operation will return to normal after executing a reset command.
Table C.5.3a Status Change of exceeded timing limits flag (DQ5)
•
Status Change in normal operation
Operation
Programming
→ complete
status
0 → DATA5
DQ5
•
Status Change in abnormal operation
Operation
Programming
Status
Operation
DQ5
1
MB90580 Series
Chip/sector erase
Sector erase wait
→ complete
0 → 1
0
Chip/sector
erase operation
1
C.5 Execution Status of Automatic Algorithm
Sector erase
→ suspend
→ start
(Sector being
erased)
0
Appendix C: The Flash Memory in the MB90F583
Sector erase
Sector erase suspend
being suspended
→ resume
(Sector not being
(Sector being erased)
0
erased)
DATA:5
365