HY29F040A Datasheet, PDF (10/40 Pages) Hynix Semiconductor – 512K x 8-bit CMOS 5.0 volt-only, Sector Erase Flash Memory

During Sector Erase operation, data bit DQ7 shows
a logical “0”. This operation is known as
/Data Polling. Sector Erase operation is complete
when data on DQ7 is a logical “1” (see Write Opera-
tion Status section) at which time the
device returns to read mode. At this time, the
address pins are no longer latched. Note that
/Data Polling must be performed at a sector
address within any of the sectors being erased and
not a protected sector to ensure that DQ7 returns
a logical “1” upon completion of the Sector Erase
operation.
Figure 2 illustrates the Sector Erase Algorithm us-
ing typical command strings and bus operations.
During execution of the Sector Erase command, only
the Erase Suspend and Erase Resume com-
mands are allowed. All other commands will reset
the device to read mode. Note: Do not attempt to
write an invalid command sequence during the
sector erase operation. Doing so will terminate the
sector erase operation and the device will reset to
the read mode.
Erase Suspend/Erase Resume
Commands
The Erase Suspend command allows the user to
interrupt a Sector Erase operation and read data
from or program to a sector that is not being erased.
The Erase Suspend command onthe HY29F040 also
allows for Byte Programming during the suspended
erase from a sector not being erased. The Erase
Suspend command is applicable only during Sector
Erase operation and will be ignored if written during
the Chip Erase operation or Byte Programming op-
eration. The Erase Suspend command (B0H) will
be allowed only during the Sector Erase opera-
tion, including, but not limited to, the sector erase
time-out period after any Sector Erase commands
(30H) have been initiated.
Writing the Erase Suspend command during the
time-out will result in immediate termination of the
time-out period. Any subsequent writes of the Sec-
tor Erase command will be taken as the Erase
Resume command (30H). Note that any other com-
mands during the time-out will reset the
device to the read mode. The address pins are
don’t-cares when writing the Erase Suspend or
Erase Resume commands.
When the Erase Suspend command is written dur-
ing a Sector Erase operation, the chip will take a
maximum of 15 ms to suspend the erase opera-
tion and go into erase suspended-read mode.
During this time, the system can monitor the /Data
Polling or Toggle Bit write operation status flags to
determine when the device has entered erase sus-
pend-read mode (see Write Operation Status sec-
tion). The system must use an address of an eras-
ing sector to monitor /Data Polling or Toggle Bit to
determine if the Sector Erase operation has been
suspended.
In the erase suspend-read mode, the system can
read data from any sector that is not being erased.
A read from a sector being erased may result in
invalid data.
After the system writes the Erase Suspend com-
mand and waits until the Toggle Bit stops toggling,
data reads from the device may then be performed.
Any further writes of the Erase Suspend command
at this time will be ignored.
To resume operation of Sector Erase, the Erase
Resume command (30H) should be written. Any
further writes of the Erase Resume command at
this point will be ignored. Another Erase Suspend
command can be written after the chip has re-
sumed the Sector Erase operation.
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HY29F040A