AM29LV641ML AMD [Advanced Micro Devices], AM29LV641ML Datasheet - Page 31

• Manufacturer Part Number: AM29LV641ML
• Manufacturer: AMD [Advanced Micro Devices]

The system can monitor DQ3 to determine if the sec-
tor erase timer has timed out (See the section on DQ3:
Sector Erase Timer.). The time-out begins from the ris-
ing edge of the final WE# pulse in the command
sequence.
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 reading DQ7, DQ6, or
DQ2 in the erasing sector. Refer to the
tion Status
Once the sector erase operation has begun, only the
Erase Suspend command is valid. All other com-
mands are ignored. However, note that a hardware
reset immediately terminates the erase operation. If
that occurs, the sector erase command sequence
should be reinitiated once the device has returned to
reading array data, to ensure data integrity.
Figure 7 illustrates the algorithm for the erase opera-
tion. Refer to the
bles in the AC Characteristics section for parameters,
and Figure 20 section for timing diagrams.
Erase Suspend/Erase Resume
Commands
The Erase Suspend command, B0h, allows the sys-
tem 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 sec-
tor erase operation, including the 50 µs time-out pe-
riod during the sector erase command sequence. The
Erase Suspend command is ignored if written during
the chip erase operation or Embedded Program
algorithm.
When the Erase Suspend command is written during
the sector erase operation, the device requires a typi-
cal of 5 µs (maximum of 20 µs) to suspend the erase
operation. However, when the Erase Suspend com-
mand is written during the sector erase time-out, the
device immediately terminates the time-out period and
suspends the erase operation.
December 21, 2005
section for information on these status bits.
Erase and Program Operations
Write Opera-
D A T A S H E E T
Am29LV641MH/L
ta-
After the erase operation has been suspended, the
device enters the erase-suspend-read mode. The sys-
tem can read data from or program data to any sector
not selected for erasure. (The device “erase sus-
pends” all sectors selected for erasure.) Reading at
any address within erase-suspended sectors pro-
duces status information 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.
Refer to the
mation on these status bits.
After an erase-suspended program operation is com-
plete, the device returns to the erase-suspend-read
mode. The system can determine the status of the
program operation using the DQ7 or DQ6 status bits,
just as in the standard word program operation.
Refer to the
information.
In the erase-suspend-read mode, the system can also
issue the autoselect command sequence. Refer to the
Autoselect Mode
sections for details.
To resume the sector erase operation, the system
must write the Erase Resume command. Further
writes of the Resume command are ignored. Another
Erase Suspend command can be written after the chip
has resumed erasing.
Note: During an erase operation, this flash device per-
forms multiple internal operations which are invisible
to the system. When an erase operation is suspended,
any of the internal operations that were not fully com-
pleted 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 suspends.
Note that the additional suspends do not affect device
reliability or future performance. In most systems rapid
erase/suspend activity occurs only briefly. In this ex-
ample, erase performance will not be significantly im-
pacted.
Write Operation Status
Write Operation Status
and
Autoselect Command Sequence
section for more
section for infor-
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