P R E L I M I N A R Y
The system can monitor DQ3 to determine if the
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 termi-
nates the time-out period and suspends the
erase operation.
sector erase timer has timed out. (See the
“DQ3: Sector Erase Timer” section.) The time-
out begins from the rising edge of the final WE#
pulse in the command sequence.
Once the sector erase operation has begun, only
the Erase Suspend command is valid. All other
commands are ignored. Note that a hardware
reset during the sector erase operation imme-
diately terminates the operation. The Sector
Erase command sequence should be reinitiated
once the device has returned to reading array
data, to ensure data integrity.
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 sectors pro-
duces status data on DQ7–DQ0. The system can
use DQ7, or DQ6 and DQ2 together, to deter-
mine if a sector is actively erasing or is erase-
suspended. See “Write Operation Status” for
information on these status bits.
When the Embedded Erase algorithm is com-
plete, the device returns to reading array data
and addresses are no longer latched. The
system can determine the status of the erase
operation by using DQ7, DQ6, DQ2, or RY/BY#.
Refer to “Write Operation Status” for informa-
tion 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 opera-
tion using the DQ7 or DQ6 status bits, just as in
the standard program operation. See “Write
Operation Status” for more information.
Figure 1 illustrates the algorithm for the erase
operation. Refer to the Erase/Program Opera-
tions tables in the “AC Characteristics” section
for parameters, and to Figure 1 for timing dia-
grams.
Erase Suspend/Erase Resume Commands
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 Command
Sequence” for more information.
The Erase Suspend command allows the system
to interrupt a sector erase operation and then
read data from, or program data to, any sector
not selected for erasure. This command is valid
only during the sector erase operation, including
the 50 µs time-out period during the sector
erase command sequence. The Erase Suspend
command is ignored if written during the chip
erase operation or Embedded Program algo-
rithm. 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.
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.
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Am29LV800D
Am29LV800D_00_A4_E January 21, 2005
AMD [ AMD ]
