AM29LV800T Datasheet, PDF (17/48 Pages) Advanced Micro Devices – 8 Megabit (1,048,576 x 8-Bit/524,288 x 16-Bit) CMOS 3.0 Volt-only, Sectored Flash Memory

PRELIMINARY
Automatic sector erase operations begin on the rising
edge of the WE (or CE) pulse of the last sector erase
command issued, and once the 80 µs time-out window
has expired. The status of the sector erase operation
can be determined three ways:
s DATA Polling of DQ7
s Checking the status of the toggle bit DQ6
s Checking the status of the RY/BY pin
Further status of device activity during the sector erase
operation can be determined using toggle bits DQ2 and
DQ3.
Figure 8 illustrates the Embedded Erase Algorithm,
using a typical command sequence and bus operations.
Erase Suspend
The Erase Suspend command allows the user to inter-
rupt a Sector Erase operation and then perform data
read or programs in a sector not being erased. This
command is applicable only during the Sector Erase
operation, which includes the time-out period for Sector
Erase. The Erase Suspend command will be ignored if
written during the execution of the Chip Erase opera-
tion or Embedded Program Algorithm (but will reset the
chip if written improperly during the command se-
quences.) Writing the Erase Suspend command during
the Sector Erase time-out results in immediate termina-
tion of the time-out period and suspension of the erase
operation. Once in Erase Suspend, the device is avail-
able for read (note that in the Erase Suspend mode, the
Reset/Read command is not required for read opera-
tions and is ignored) or program operations in sectors
not being erased. Any other command written during
the Erase Suspend mode will be ignored, except for the
Erase Resume command. Writing the Erase Resume
command resumes the sector erase operation. The ad-
dresses are “don’t cares” when writing the Erase Sus-
pend or Erase Resume command.
When the Erase Suspend command is written during a
Sector Erase operation, the chip will take between 0.1
µs and 20 µs to actually suspend the operation and go
into erase suspended read mode (pseudo-read mode),
at which time the user can read or program from a sec-
tor that is not erase suspended. Reading data in this
mode is the same as reading from the standard read
mode, except that the data must be read from sectors
that have not been erase suspended.
Successively reading from the erase-suspended sector
while the device is in the erase-suspend-read mode will
cause DQ2 to toggle. Polling DQ2 on successive reads
from a given sector provides the system the ability to
determine if a sector is in Erase Suspend.
After entering the erase-suspend-read mode, the user
can program the device by writing the appropriate com-
mand sequence for Byte Program. This program mode
is known as the erase suspend-program mode. Again,
programming in this mode is the same as programming
in the regular Byte Program mode, except that the data
must be programmed to sectors that are not erase sus-
pended. Successively reading from the erase sus-
pended sector while the device is in the erase
suspend-program mode will cause DQ2 to toggle.
Completion of the erase suspend operation can be de-
termined two ways:
s Checking the status of the toggle bit DQ2
s Checking the status of the RY/BY pin
To resume the operation of Sector Erase, the Resume
command (30h) should be written. Any further writes of
the Resume command at this point will be ignored. How-
ever, another Erase Suspend command can be written
after the device has resumed sector erase operations.
When the erase operation has been suspended, the de-
vice defaults to the erase-suspend-read mode. Reading
data in this mode is the same as reading from the stan-
dard read mode except that the data must be read from
sectors that have not been erase-suspended.
To resume the operation of Sector Erase, the Resume
command (30h) should be written. Any further writes of
the Resume command at this point will be ignored. An-
other Erase Suspend command can be written after the
chip has resumed erasing.
Am29LV800T/Am29LV800B
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