D A T A S H E E T
an all zero data pattern prior to electrical erase. The
system is not required to provide any controls or tim-
ings during these operations.
After the command sequence is written, a sector erase
time-out of 50 µs occurs. During the time-out period,
additional sector addresses and sector erase com-
mands may be written. Loading the sector erase buffer
may be done in any sequence, and the number of sec-
tors may be from one sector to all sectors. The time
between these additional cycles must be less than 50
µs, otherwise erasure may begin. Any sector erase ad-
dress and command following the exceeded time-out
may or may not be accepted. It is recommended that
processor interrupts be disabled during this time to en-
sure all commands are accepted. The interrupts can
be re-enabled after the last Sector Erase command is
written.
Any command other than Sector Erase or
Erase Suspend during the time-out period resets
the device to the read mode.
The system must re-
write the command sequence and any additional ad-
dresses and commands.
Note that the SecSi Sector,
autoselect, and CFI functions are unavailable when an
erase operation is in progress.
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
Write Opera-
tion Status
section for information on these status bits.
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
Erase and Program Operations
ta-
bles in the AC Characteristics section for parameters,
and Figure 19 section for timing diagrams.
START
Write Erase
Command Sequence
(Notes 1, 2)
Data Poll to Erasing
Bank from System
Embedded
Erase
algorithm
in progress
No
Data = FFh?
Yes
Erasure Completed
Notes:
1. See Tables
10
and
11
for erase command sequence.
2. See the section on DQ3 for information on the sector erase timer.
Figure 7.
Erase Operation
December 14, 2005
Am29LV640MH/L
31
SPANSION [ SPANSION ]
