WRITE OPERATION STATUS
The device provides several bits to determine the sta-
tus of a write operation: DQ3, DQ5, DQ6, and DQ7.
Table 5 and the following subsections describe the
functions of these bits. DQ7 and DQ6 each offer a
method for determining whether a program or erase
operation is complete or in progress. These three bits
are discussed first.
Table 5 shows the outputs for Data# Polling on DQ7.
Figure 3 shows the Data# Polling algorithm.
START
DQ7: Data# Polling
Read DQ7–DQ0
Addr = VA
The Data# Polling bit, DQ7, indicates to the host
system whether an Embedded Algorithm is in
progress or completed. Data# Polling is valid after
the rising edge of the final WE# pulse in the program
or erase command sequence.
Yes
DQ7 = Data?
During the Embedded Program algorithm, the device
outputs on DQ7 the complement of the datum pro-
grammed to DQ7. When the Embedded Program algo-
rithm 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 sec-
tor, Data# Polling on DQ7 is active for approximately 2
µs, then the device returns to reading array data.
No
No
DQ5 = 1?
Yes
During the Embedded Erase algorithm, Data# Polling
produces a “0” on DQ7. When the Embedded Erase al-
gorithm is complete, Data# Polling produces a “1” on
DQ7. This is analogous to the complement/true datum
output described for the Embedded Program algorithm:
the erase function changes all the bits in a sector to “1”;
prior to this, the device outputs the “complement,” or
“0.” The system must provide an address within any of
the sectors selected for erasure to read valid status in-
formation on DQ7.
Read DQ7–DQ0
Addr = VA
Yes
DQ7 = Data?
After an erase command sequence is written, if all sec-
tors selected for erasing are protected, Data# Polling
on DQ7 is active for approximately 100 µs, then the de-
vice returns to reading array data. If not all selected
sectors are protected, the Embedded Erase algorithm
erases the unprotected sectors, and ignores the se-
lected sectors that are protected.
No
PASS
FAIL
Notes:
1. VA = Valid address for programming. During a sector
erase operation, a valid address is an address within any
sector selected for erasure. During chip erase, a valid
address is any non-protected sector address.
When the system detects DQ7 has changed from the
complement to true data, it can read valid data at DQ7–
DQ0 on the following read cycles. This is because DQ7
may change asynchronously with DQ0–DQ6 while
Output Enable (OE#) is asserted low. The Data# Poll-
ing Timings (During Embedded Algorithms) figure in
the “AC Characteristics” section illustrates this.
2. DQ7 should be rechecked even if DQ5 = “1” because
DQ7 may change simultaneously with DQ5.
16736G-9
Figure 3. Data# Polling Algorithm
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