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S29CD-J & S29CL-J Flash Family
S29CD-J_CL-J_00_B1 September27,2006
Prel imi n ary
8.8.1
DQ7: Data# Polling
The Data# Polling bit, DQ7, indicates to the host system whether an Embedded Program or Erase
algorithm is in progress or completed, or whether a bank is in Erase Suspend. Data# Polling is
valid after the rising edge of the final WE# pulse in the command sequence. Note that Data#
Polling returns invalid data for the address being programmed or erased.
During the Embedded Program algorithm, the device outputs on DQ7 the complement of the
datum programmed to DQ7. This DQ7 status also applies to programming during Erase Suspend.
When the Embedded Program algorithm is complete, the device outputs the datum programmed
to DQ7. The system must provide the program address to read valid status information on DQ7.
If a program address falls within a protected sector, Data# polling on DQ7 is active for approxi-
mately 1 s, then that bank returns to the read mode without programming the sector. If an
erase address falls within a protected sector, Toggle BIT (DQ6) is active for 150 s, then the device
returns to the read mode without erasing the sector. Please note that Data# polling (DQ7) may
give misleading status when an attempt is made to program or erase a protected sector.
During the Embedded Erase Algorithm, Data# polling produces a "0" on DQ7. When the Embed-
ded Erase algorithm is complete Data# Polling produces a "1" on DQ7. The system must provide
an address within any of the sectors selected for erasure to read valid status information on DQ7.
In asynchronous mode, just prior to the completion of an Embedded Program or Erase operation,
DQ7 may change asynchronously with DQ6-DQ0 while Output Enable (OE#) is asserted low. That
is, the device may change from providing status information to valid data on DQ7. Depending
on when the system samples the DQ7 output, it may read the status or valid data. Even if the
device has completed the program or erase operation and DQ7 has valid data, the data outputs
on DQ6-DQ0 may be still invalid. Valid data on DQ7-D00 appears on successive read cycles.
Data# Polling timing diagram.