D A T A S H E E T
WRITE OPERATION STATUS
The device provides several bits to determine the sta-
tus of a write operation: DQ2, DQ3, DQ5, DQ6, DQ7,
and RY/BY#. Table 6 and the following subsections
describe the functions of these bits. DQ7, RY/BY#,
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 6 shows the outputs for Data# Polling on DQ7.
Figure 5 shows the Data# Polling algorithm.
START
DQ7: Data# Polling
Read DQ7–DQ0
Addr = VA
The Data# Polling bit, DQ7, indicates to the host sys-
tem whether an Embedded Algorithm is in progress or
completed, or whether the device is in Erase Suspend.
Data# Polling is valid after the rising edge of the final
WE# pulse in the program or erase command se-
quence.
Yes
DQ7 = Data?
During the Embedded Program algorithm, the device
outputs on DQ7 the complement of the datum pro-
grammed to DQ7. This DQ7 status also applies to pro-
gramming 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
approximately 1 µs, then the device returns to reading
array data.
No
No
DQ5 = 1?
Yes
Read DQ7–DQ0
Addr = VA
During the Embedded Erase algorithm, Data# Polling
produces a “0” on DQ7. When the Embedded Erase
algorithm is complete, or if the device enters the Erase
Suspend mode, Data# Polling produces a “1” on DQ7.
This is analogous to the complement/true datum out-
put 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
information on DQ7.
Yes
DQ7 = Data?
No
PASS
FAIL
After an erase command sequence is written, if all
sectors selected for erasing are protected, Data# Poll-
ing on DQ7 is active for approximately 100 µs, then the
device 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.
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.
2. DQ7 should be rechecked even if DQ5 = “1” because
DQ7 may change simultaneously with DQ5.
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 be-
cause DQ7 may change asynchronously with
DQ0–DQ6 while Output Enable (OE#) is asserted low.
Figure 19, Data# Polling Timings (During Embedded
Algorithms), in the “AC Characteristics” section illus-
trates this.
Figure 5. Data# Polling Algorithm
20
Am29LV400B
21523D4 December 4, 2006
SPANSION [ SPANSION ]
