Suspend command is ignored if written during the chip erase operation or Em-
bedded Program algorithm. Writing the Erase Suspend command during the
Sector Erase time-out immediately terminates the time-out period and suspends
the erase operation. Addresses are “don’t-cares” when writing the Erase Suspend
command.
When the Erase Suspend command is written during a sector erase operation, the
device requires a maximum of 20 µs to suspend the erase operation. However,
when the Erase Suspend command is written during the sector erase time-out,
the device immediately terminates the time-out period and suspends the erase
operation.
After the erase operation has been suspended, the system can read array data
from or program data to any sector not selected for erasure. (The device “erase
suspends” all sectors selected for erasure.) Normal read and write timings and
command definitions apply. Reading at any address within erase-suspended sec-
tors produces status data on DQ7–DQ0. The system can use DQ7, or DQ6 and
DQ2 together, to determine if a sector is actively erasing or is erase-suspended.
See “Write Operation Status” for information on these status bits.
After an erase-suspended program operation is complete, the system can once
again read array data within non-suspended sectors. The system can determine
the status of the program operation using the DQ7 or DQ6 status bits, just as in
the standard program operation. See “Write Operation Status” for more
information.
The system may also write the autoselect command sequence when the device
is in the Erase Suspend mode. The device allows reading autoselect codes even
at addresses within erasing sectors, since the codes are not stored in the memory
array. When the device exits the autoselect mode, the device reverts to the Erase
Suspend mode, and is ready for another valid operation. See “Autoselect Com-
mand Sequence” for more information.
The system must write the Erase Resume command (address bits are “don’t
care”) to exit the erase suspend mode and continue the sector erase operation.
Further writes of the Resume command are ignored. Another Erase Suspend
command can be written after the device has resumed erasing.
Note: During an erase operation, this flash device performs multiple internal op-
erations that are invisible to the system. When an erase operation is suspended,
any of the internal operations that were not fully completed must be restarted.
As such, if this flash device is continually issued suspend/resume commands in
rapid succession, erase progress will be impeded as a function of the number of
suspends. The result will be a longer cumulative erase time than without sus-
pends. Note that the additional suspends do not affect device reliability or future
performance. In most systems rapid erase/suspend activity occurs only briefly.
In such cases, erase performance will not be significantly impacted.
29
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SPANSION [ SPANSION ]
