P r e l i m i n a r y
Write Operation Status
The device provides several bits to determine the status of a program or erase
operation: DQ2, DQ3, DQ5, DQ6, and DQ7. Table 16, “Write Operation Status,”
on page 42 and the following subsections describe the function of these bits. DQ7
and DQ6 each offers a method for determining whether a program or erase op-
eration is complete or in progress.
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.
During the Embedded Program algorithm, the device outputs on DQ7 the com-
plement 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 pro-
gram address falls within a protected sector, Data# Polling on DQ7 is active for
approximately 1 µs, then that bank returns to the read mode.
During the Embedded Erase algorithm, Data# Polling produces a “0” on DQ7.
When the Embedded Erase algorithm is complete, or if the bank enters the Erase
Suspend mode, 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 in-
formation on DQ7.
After an erase command sequence is written, if all sectors selected for erasing
are protected, Data# Polling on DQ7 is active for approximately 100 µs, then the
bank returns to the read mode. If not all selected sectors are protected, the Em-
bedded Erase algorithm erases the unprotected sectors, and ignores the selected
sectors that are protected. However, if the system reads DQ7 at an address within
a protected sector, the status may not be valid.
Just prior to the completion of an Embedded Program or Erase operation, DQ7
may change asynchronously with DQ6–DQ0 while Output Enable (OE#) is as-
serted 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–DQ0 will appear on successive read cycles.
Table 16 shows the outputs for Data# Polling on DQ7. Figure 3 shows the Data#
Polling
algorithm.
Figure 27,
“Data#
Polling
Timings
(During Embedded Algorithm),” on page 64 in the AC Characteristics section
shows the Data# Polling timing diagram.
October 1, 2003 27243B1
Am29BDS320G
37
SPANSION [ SPANSION ]
