AUSTIN SEMICONDUCTOR, INC.
FLASH
AS8FLC1M32
Austin Semiconductor, Inc.
The remaining scenario is that the system initially determines
that the toggle bit is toggling and DQ5, 13, 21, and or DQ29 has
not gone High. The system may continue to monitor the toggle
bit and DQ5, 13, 21, and or DQ29 through successive READ
cycles, determining the status as described in the previous
paragraph. Alternatively, it may choose to perform other system
tasks. In this case, the system must start at the beginning of
the Algorithm when it returns to determine the status of the
operation.
DQ5,13,21,and or DQ29: Exceeding Timing Limits
DQ5, 13, 21, and or DQ29 indicates whether the PROGRAM or
ERASE time has exceeded a specified internal pulse count limit.
Under these conditions this will produce a logic level “1” High.
This is a failure condition that indicates the PROGRAM or
ERASE cycle was not successfully completed.
The DQ5, 13, 21 and or DQ29 failure condition may appear if
the system tries to PROGRAM a “1” to a location that was
previously PROGRAMMED to a logic level “0” Low. Only an
ERASE operation can change a logic level “0” back to a Logic
Level “1”. Under this condition, the device halts operation
and when the operation has exceeded the timing limits, DQ5,
13, 21, and or DQ29 will produce a logic level “1”.
Toggle BitAlgorithm Diagram
Start
READ(#1) Byte
Data from Byte1, 2,
3 and or 4
Under both of these conditions, the system must issue the
RESET command to return to reading array data.
DQ3, 11, 19, and or DQ27: Sector Erase Timer
After WRITING a Sector Erase command sequence, the system
may read this status bit or bits to determine whether or not an
ERASE operation has begun. If additional sectors are selected
for ERASURE, the entire time-out also applies after each
additional Sector Erase command. When the time-out is
complete, this status bit or bits changes from a logic level “0”
to “1”. The system may ignore this status bit if the system can
guarantee that the time between additional Sector Erase
command will always be less than 50us.
READ(#2) Byte
Data from Byte1, 2,
3 and or 4
NO
Toggle Bit =
Toggle?
YES
DQ5, 13, 21
and or DQ29 =
"1"
NO
After the Sector Erase command sequence is WRITTEN, the
system should read the status on DQ7, 15, 23 and or DQ31
(Data\ Polling) or DQ6, 14, 22, and or DQ30 (Toggle Bit I) to
ensure the device has accepted the command sequence. Then
READ DQ3, 11, 19 and or DQ27, looking for this bit or bits to be
a logic level “1”. If this bit is a logic level “1”, the internally
controlled ERASE cycle has begun; all further commands are
ignored until the ERASE operation is complete. If this bit is a
logic level “0”, the device will accept additional Sector Erase
commands. To ensure the command has been accepted, the
system software should check the status of DQ3, 11, 19 and or
DQ27 prior to and following each subsequent Sector Erase
command. If this bit or bits is a logic level “1” on the second
status check, the last command might not have been accepted.
YES
READ(#1) Byte
Data from Byte1, 2,
3 and or 4
READ(#2) Byte
Data from Byte1, 2,
3 and or 4
NO
Toggle Bit =
Toggle?
YES
Operation Not
Complete, WRITE
RESET Command
PROGRAM/
ERASE Complete
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
AS8FLC1M32B
Rev. 3.3 05/08
13
AUSTIN [ AUSTIN SEMICONDUCTOR ]
