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Item
Description
Erase suspend allows interruption of sector erase operations to perform data reads from a sector
not being erased. Erase suspend applies only during sector erase operations, including the time-
out period. Writing an Erase Suspend command during sector erase time-out results in immediate
termination of time-out period and suspension of erase operation.
AS29F002 ignores any commands during erase suspend other than the Reset or Erase Resume
commands. Writing erase resume continues erase operations. Addresses are DON’T CARE when
writing Erase Suspend or Erase Resume commands.
AS29F002 takes 0.2–15 µs to suspend erase operations after receiving Erase Suspend command.
Check completion of erase suspend by polling DQ7 and/ or DQ6. To determine completion of
erase suspend, either check DQ6 after selecting an address of a sector not being erased, or poll
RY/ BY. Check DQ2 in conjunction with DQ6 to determine if a sector is being erased. AS29F002
ignores redundant writes of erase suspend.
Erase Suspend
AS29F002 defaults to erase-suspend-read mode while an erase operation has been suspended.
While in erase-suspend mode AS29F002 allows reading data (erase-suspend-read mode) from or
programming data (erase-suspend-program mode) to any sector not undergoing sector erase,
treated as standard read or standard programming mode. AS29F002 defaults to erase-suspend-
read mode while an erase operation has been suspended.
Write the Resume command 30h to continue operation of sector erase. AS29F002 ignores
redundant writes of the Resume command. AS29F002 permits multiple suspend/ resume
operations during sector erase.
When attempting to write to a protected sector, DATA polling and Toggle Bit 1 (DQ6) are
activated for about <1 µs. When attempting to erase a protected sector, DATA polling and Toggle
Bit 1 (DQ6) are activated for about <5 µs. In both cases, the device returns to read mode without
altering the specified sectors.
Sector Protect
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Only active during automated on-chip algorithms or sector erase time outs. DQ7 reflects
complement of data last written when read during the automated on-chip algorithm (0 during
erase algorithm); reflects true data when read after completion of an automated on-chip
algorithm (1 after completion of erase agorithm).
DATA polling (DQ7)
Active during automated on-chip algorithms or sector erase time outs. DQ6 toggles when CE or
OE toggles, or an Erase Resume command is invoked. DQ6 is valid after the rising edge of the
fourth pulse of WE during programming; after the rising edge of the sixth WE pulse during chip
erase; after the last rising edge of the sector erase WE pulse for sector erase. For protected sectors,
DQ6 toggles for only <1 µs during writes, and <5 µs during erase (if all selected sectors are
protected).
Toggle bit (DQ6)
Indicates unsuccessful completion of program/ erase operation (DQ5 = 1). DATA polling remains
active; CE powers the device down to 2 mA. If DQ5 = 1 during chip erase, all or some sectors are
defective; during byte programming, the entire sector is defective; during sector erase, the sector
is defective (in this case, reset the device and execute a program or erase command sequence to
continue working with functional sectors). Attempting to program 0 to 1 will set DQ5 = 1.
Exceeding time limit
(DQ5)
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ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
