D A T A S H E E T
The system can monitor DQ3 to determine if the sector
After an erase-suspended program operation is complete,
the system can once again read array data within non-sus-
pended 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‚ on page 19 for more information.
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 ig-
nored. 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 in-
tegrity.
The system may also write the autoselect command se-
quence 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 Se-
quence‚ on page 15 for more information.
When the Embedded Erase algorithm is complete, the de-
vice 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#. (Re-
fer to Write Operation Status‚ on page 19 for information on
these status bits.)
The system must write the Erase Resume command (ad-
dress 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 eras-
ing.
Figure 4 illustrates the algorithm for the erase operation.
Refer to the Erase/Program Operations‚ on page 30 for pa-
rameters, and to Figure 18‚ on page 32 for timing diagrams.
Erase Suspend/Erase Resume Commands
The Erase Suspend command allows the system to interrupt
a sector erase operation and then read data from, or pro-
gram data to, any sector not selected for erasure. This com-
mand 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 ig-
nored if written during the chip erase operation or Embedded
Program algorithm. Writing the Erase Suspend command
during the Sector Erase time-out immediately terminates the
time-out period and suspends the erase operation. Ad-
dresses 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 sec-
tor 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 pe-
riod 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 to-
gether, to determine if a sector is actively erasing or is
erase-suspended. See Write Operation Status‚ on page 19
for information on these status bits.
Yes
Erasure Completed
Notes:
1. See Table 5 on page 18 for erase command sequence.
2. See DQ3: Sector Erase Timer‚ on page 21 for more information.
Figure 4. Erase Operation
January 23, 2007 Am29SL400C_00_A6
Am29SL400C
17
AMD [ AMD ]
