W19B(L)320ST/B
The device may output “1” on DQ5 if the system tries to program “1” to a location that was previously
programmed to “0.” Only the erase operation can change “0” back to “1.” Under this condition, the device
stops the operation, and while the timing limit has been exceeded, DQ5 produces “1.”
Under both these conditions, the system must write the reset command to return to the read mode (or
to the erase-suspend-read mode if the device was previously in the erase-suspend-program mode).
6.3.7 DQ3: Sector Erase Timer
After writing a sector erase command sequence, the system may read DQ3 to determine whether
erasure has begun or not. (The sector erase timer does not apply to the chip erase command.) The
entire time-out applies after each additional sector erase command if additional sectors are selected
for erasure. Once the timeout period has completed, DQ3 switches from “0” to “1.” If the time between
additional sector erase commands from the system can be assumed to be less than 50 µS, the
system need not monitor, DQ3 does not need to be monitored. Please also refer to Sector Erase
Command Sequence section.
After the sector erase command is written, the system should read the status of DQ7 (#Data Polling)
or DQ6 (Toggle Bit I) to ensure that the device has accepted the command sequence, and then read
DQ3. If DQ3 is“1,” the Embedded Erase algorithm has begun; all further commands (except Erase
Suspend) are ignored until the erase operation is complete. If DQ3 is “0,” the device will accept
additional sector erase commands.
The system software should check the status of DQ3 before and following each subsequent sector
erase command to ensure the command has been accepted. If DQ3 is high on the second status
check, the last command might not have been accepted.
Publication Release Date: March 23, 2004
- 17 -
Revision A2
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