BOOT SECTOR FLASH
Austin Semiconductor, Inc.
ERASE SUSPEND / ERASE RESUME
The Erase Suspend command allows the system 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 during the chip erase
operation or Embedded Program algorithm. Writing the
Erase Suspend command during the Sector Erase time-
out immediately terminates the time-out period and
suspends the erase operation. Addresses are don’t-cares
when writing the Erase Suspend command.
When the Erase Suspend command is written during a
sector erase operation, the device requires a maximum
of 20 µs to suspend the erase operation. However, when
the Erase Suspend command is written during the sector
erase time-out, the device immediately terminates the
time-out period and suspends the erase operation.
After the erase operation has been suspended, the system
can read array data from or program data to any sector
not selected for erasure. (The device “erase suspends”
all sectors selected for erasure.) Normal read and write
timings and command definitions apply. Reading at any
address within erase-suspended sectors produces status
data 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. See Write Operation
Status on page 22 for information on these status bits.
After an erase-suspended program operation is complete,
the system can once again read array data within non-
suspended sectors. The system can determine the status
of the program operation using the DQ7 or DQ6 status
bits, just as in the standard program operation. See Write
Operation Status on page 22 for more information.
The system may also write the autoselect command
sequence when the device is in the Erase Suspend mode.
The device allows reading autoselect codes even at
addresses within erasing sectors, since the codes are
not stored in the memory array. When the device exits
the autoselect mode, the device reverts to the Erase
Suspend mode, and is ready for another valid operation.
See Autoselect Command Sequence on page 17 for more
The system must write the Erase Resume command
(address bits are don’t care) to exit the erase suspend
mode and continue the sector erase operation. Further
writes of the Resume command are ignored. Another
Erase Suspend command can be written after the device
has resumed erasing.
Data = FFh?
1. See Table 9 on page 21 for erase command
2. See DQ3: Sector Erase Timer on page 25 for more
Figure 4. Erase Operation
Rev. 0.0 02/09
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