DATA SHEET
WRITE OPERATION STATUS
The device provides several bits to determine the
status of a write operation: DQ2, DQ3, DQ5, DQ6,
DQ7, and RY/BY#. Table 6 and the following subsec-
tions 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.
START
DQ7: Data# Polling
The Data# Polling bit, DQ7, indicates to the host
system whether an Embedded Algorithm is in progress
or completed, or whether the device is in Erase Sus-
pend. Data# Polling is valid after the rising edge of the
final WE# pulse in the program or erase command
sequence.
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
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
approximately 1 µs, then the device returns to reading
array data.
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 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
information 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 device returns to reading array data. If not all
selected sectors are protected, the Embedded Erase
algorithm erases the unprotected sectors, and ignores
the selected sectors that are protected.
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. Figure 17, Data#
Read DQ7–DQ0
Addr = VA
DQ7 = Data?
Yes
No
No
DQ5 = 1?
Yes
Read DQ7–DQ0
Addr = VA
DQ7 = Data?
Yes
No
FAIL
PASS
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.
Figure 5.
Data# Polling Algorithm
21522D5 October 11, 2006
Am29LV004B
19
AMD [ ADVANCED MICRO DEVICES ]
