A D V A N C E I N F O R M A T I O N
Once the sector erase operation has begun, only the
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 oper-
ation. See Write Operation Status, on page 18 for
more information.
Erase Suspend command is valid. All other commands
are ignored. Note that a hardware reset during the
sector erase operation immediately terminates the
operation. The Sector Erase command sequence
should be reinitiated once the device has returned to
reading array data, to ensure data integrity.
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, on page 14 for more information.
When the Embedded Erase algorithm is complete, 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, on
page 18 for information on these status bits.)
Figure 4 illustrates the algorithm for the erase opera-
tion. Refer to the Erase/Program Operations, on
page 29 for parameters, and to Figure 18, on page 31
for timing diagrams.
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.
Erase Suspend/Erase Resume Commands
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.
START
Write Erase
Command Sequence
Data Poll
from System
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 ter-
minates the time-out period and suspends the erase
operation.
Embedded
Erase
algorithm
in progress
No
Data = FFh?
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 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-sus-
pended. See Write Operation Status, on page 18 for
information on these status bits.
Yes
Erasure Completed
Notes:
1. See Table 5 on page 17 for erase command sequence.
2. See DQ3: Sector Erase Timer, on page 20 for more infor-
mation.
Figure 4. Erase Operation
After an erase-suspended program operation is com-
plete, the system can once again read array data within
16
Am29SL400D
Rev. A Amend. +1 April 13, 2005
AMD [ AMD ]
