D A T A S H E E T
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 on page 22 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.
START
Read DQ7–DQ0
Addr = VA
DQ7: Data# Polling
The Data# Polling bit, DQ7, indicates to the host system
whether an Embedded Algorithm is in progress or com-
pleted, 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 sequence.
Yes
DQ7 = Data?
During the Embedded Program algorithm, the device out-
puts 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
approximately 1 µs, then the device returns to reading array
data.
No
No
DQ5 = 1?
Yes
During the Embedded Erase algorithm, Data# Polling pro-
duces 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 comple-
ment, or 0. The system must provide an address within any
of the sectors selected for erasure to read valid status infor-
mation on DQ7.
Read DQ7–DQ0
Addr = VA
Yes
DQ7 = Data?
No
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 sec-
tors, and ignores the selected sectors that are protected.
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 com-
plement 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 19‚ on page 33 Data# Polling Timings
(During Embedded Algorithms), illustrates this.
2. DQ7 should be rechecked even if DQ5 = 1 because DQ7 may
change simultaneously with DQ5.
Figure 5. Data# Polling Algorithm
Table 6 on page 22 shows the outputs for Data# Polling on
DQ7. Figure 5 shows the Data# Polling algorithm.
RY/BY#: Ready/Busy#
The RY/BY# is a dedicated, open-drain output pin that indi-
cates whether an Embedded Algorithm is in progress or
complete. The RY/BY# status is valid after the rising edge of
the final WE# pulse in the command sequence. Since
RY/BY# is an open-drain output, several RY/BY# pins can be
tied together in parallel with a pull-up resistor to VCC
.
January 23, 2007 Am29SL400C_00_A6
Am29SL400C
19
AMD [ AMD ]
