D A T A S H E E T
number of sectors may be from one sector to all sec-
tors. The time between these additional cycles must be
less than t , otherwise erasure may begin. Any
Erase Suspend/Erase Resume Commands
The Erase Suspend command, B0h, allows the system
to interrupt a sector erase operation and then read data
from, or program data to, any sector not selected for
erasure. The bank address is required when writing
this command. This command is valid only during the
SEA
sector erase address and command following the
exceeded time-out, t may or may not be accepted.
SEA,
It is recommended that processor interrupts be dis-
abled 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 Sector Erase or Erase Suspend during the
time-out period resets that bank to the read mode. The
system must rewrite the command sequence and any
additional addresses and commands.
sector erase operation, including the minimum t
SEA
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 algorithm.
When the Erase Suspend command is written during
the sector erase operation, the device requires a
The system can monitor DQ3 to determine if the sector
erase timer has timed out (See “DQ3: Sector Erase
Timer” section on page 51.) The time-out begins from
the rising edge of the final WE# pulse in the command
sequence.
maximum of t
to suspend the erase operation. How-
ESL
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.
When the Embedded Erase algorithm is complete, the
bank 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 bank. The system can determine the
status of the erase operation by reading DQ7 or
DQ6/DQ2 in the erasing bank. Refer to the “Write
Operation Status” section on page 48 for information
on these status bits.
After the erase operation has been suspended, the
bank enters the erase-suspend-read mode. The
system 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 produces
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 Figure , “Write Operation Status,” on page 48 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. However, note that a hardware reset
immediately terminates the erase operation. If that
occurs, the sector erase command sequence should
be reinitiated once that bank has returned to reading
array data, to ensure data integrity.
After an erase-suspended program operation is com-
plete, the bank 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 program operation. Refer to the
“Write Operation Status” section on page 48 for more
information.
The host system may also initiate the sector erase
command sequence while the device is in the unlock
bypass mode. The command sequence is four cycles
cycles in length instead of six cycles. The Unlock
Bypass Reset Command is required to return to
reading array data when the bank is in the unlock
bypass mode.
In the erase-suspend-read mode, the system can also
issue the autoselect command sequence. Refer to the
“Autoselect Mode” section on page 14 and “Autoselect
Command Sequence” section on page 36 for details.
To resume the sector erase operation, the system must
write the Erase Resume command. The bank address
of the erase-suspended bank is required when writing
this command. Further writes of the Resume command
Figure 5, “Erase Operation,” on page 40 illustrates the
algorithm for the erase operation. Refer to the
Erase/Program Operations table in the Figure , “AC
Characteristics,” on page 69 for parameters and timing
diagrams.
May 10, 2006 27024B3
Am29BDS128H/Am29BDS640H
39
SPANSION [ SPANSION ]
