D A T A S H E E T
this time to ensure all commands are accepted. The
time-out period and suspends the erase operation.
Addresses are “don’t-cares” when writing the Erase
Suspend command.
interrupts can be re-enabled after the last Sector Erase
command is written. If the time between additional
sector erase commands can be assumed to be less
than 50 µs, the system need not monitor DQ3. Any
command other than Sector Erase or Erase
Suspend during the time-out period resets the
device to reading array data. The system must
rewrite the command sequence and any additional
sector addresses and commands.
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.
The system can monitor DQ3 to determine if the sector
erase timer has timed out. (See DQ3: Sector Erase
Timer‚ on page 22.) The time-out begins from the rising
edge of the final WE# pulse in the command sequence.
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 20 for
information on these status bits.
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 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.
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 20 for information on these status bits.)
After an erase-suspended program operation is com-
plete, 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 oper-
ation. See Write Operation Status‚ on page 20 for
more information.
Figure 4, on page 18 illustrates the algorithm for the
erase operation. Refer to the Table 16 on page 39for
parameters, and to Figure 18, on page 33 for timing
diagrams.
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 15 for more information.
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
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.
January 23, 2007 27546A6
Am29SL800D
17
AMD [ AMD ]
