am41pds3224d Meet Spansion Inc., am41pds3224d Datasheet - Page 26

• Manufacturer Part Number: am41pds3224d
• Description: 32 Mbit 2 M ? 16-bit Cmos 1.8 Volt-only, Simultaneous Operation Page Mode Flash Memory And 4 Mbit 512 K ? 8-bit/256 K ? 16-bit Static Ram Preliminary
• Manufacturer: Meet Spansion Inc.

When the Embedded Erase algorithm is complete, the
device returns to the read mode 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 the Flash Write Operation Status
section for information on these status bits.
Any commands written during the chip erase operation
are ignored. However, note that a hardware reset im-
mediately terminates the erase operation. If that oc-
curs, the chip erase command sequence should be
reinitiated once the device has returned to reading
array data, to ensure data integrity.
Figure 5 illustrates the algorithm for the erase opera-
tion. Refer to the Flash Erase and Program Opera-
tions tables in the AC Characteristics section for
parameters, and Figure 20 section for timing dia-
grams.
Sector Erase Command Sequence
Sector erase is a six bus cycle operation. The sector
erase command sequence is initiated by writing two
unlock cycles, followed by a set-up command. Two ad-
ditional unlock cycles are written, and are then fol-
lowed by the address of the sector to be erased, and
the sector erase command. Table 10 shows the ad-
dress and data requirements for the sector erase com-
mand sequence.
The device does not require the system to preprogram
prior to erase. The Embedded Erase algorithm auto-
matically programs and verifies the entire memory for
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 comma nd following the excee ded
time-out may or may not be accepted. It is recom-
mended that processor interrupts be disabled during
this time to ensure all commands are accepted. The
interrupts can be re-enabled after the last Sector
Erase command is written. Any command other than
S ec t or E r a s e or E r a s e S u s pe n d du r i ng th e
time-out period resets the device to the read
mode. The system must rewrite the command se-
quence and any additional addresses and commands.
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-
May 13, 2002
P R E L I M I N A R Y
Am41PDS3224D
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. Note that while the Embedded
Erase operation is in progress, the system can read
data from the non-erasing sector. The system can de-
termine the status of the erase operation by reading
DQ7, DQ6, DQ2, or RY/BY# in the erasing sector.
Refer to the Flash Write Operation 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 5 illustrates the algorithm for the erase opera-
tion. Refer to the Flash Erase and Program Opera-
tions tables in the AC Characteristics section for
parameters, and Figure 20 section for timing dia-
grams.
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
sector erase operation, including the 50 µs time-out
period during the sector erase command sequence.
The Erase Suspend command is ignored if written dur-
ing the chip erase operation or Embedded Program
algorithm.
When the Erase Suspend command is written during
the sector erase operation, the device requires a max-
imum of 20 µs to suspend the erase operation. How-
ever, when the Erase Suspend command is written
during the sector erase time-out, the device immedi-
ately terminates the time-out period and suspends the
erase operation.
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.) Note that un-
lock bypass programming is not allowed when the
device is erase-suspended.
Reading at any address within erase-suspended sec-
tors produces status information on DQ7–DQ0. The
system can use DQ7, or DQ6 and DQ2 together, to
de t e rm in e if a se ct o r is a ct ive ly e ra si ng o r is
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