tional sectors are selected for erasure, the entire time-
out also applies after each additional sector erase com-
mand. When the time-out is complete, DQ3 switches
from “0” to “1.” If the time between additional sector
erase commands from the system can be assumed to
be less than 50 µs, the system need not monitor DQ3.
See also the “Sector Erase Command Sequence” sec-
tion.
DQ5: Exceeded Timing Limits
DQ5 indicates whether the program or erase time has
exceeded a specified internal pulse count limit. Under
these conditions DQ5 produces a “1.” This is a failure
condition that indicates the program or erase cycle was
not successfully completed.
The DQ5 failure condition may appear if the system
tries to program a “1” to a location that is previously pro-
grammed to “0.” Only an erase operation can change
a “0” back to a “1.” Under this condition, the device
halts the operation, and when the operation has ex-
ceeded the timing limits, DQ5 produces a “1.”
After the sector erase command sequence is written,
the system should read the status on DQ7 (Data# Poll-
ing) or DQ6 (Toggle Bit I) to ensure the device has ac-
cepted the command sequence, and then read DQ3. If
DQ3 is “1”, the internally controlled erase cycle has be-
gun; all further commands (other than Erase Suspend)
are ignored until the erase operation is complete. If
DQ3 is “0”, the device will accept additional sector
erase commands. To ensure the command has been
accepted, the system software should check the status
of DQ3 prior to and following each subsequent sector
erase command. If DQ3 is high on the second status
check, the last command might not have been ac-
cepted. Table 9 shows the outputs for DQ3.
Under both these conditions, the system must issue the
reset command to return the device to reading array
data.
DQ3: Sector Erase Timer
After writing a sector erase command sequence, the
system may read DQ3 to determine whether or not an
erase operation has begun. (The sector erase timer
does not apply to the chip erase command.) If addi-
Table 9. Write Operation Status
DQ7
DQ5
DQ2
Operation
(Note 2)
DQ6
(Note 1)
DQ3
N/A
1
(Note 2)
RY/BY#
Embedded Program Algorithm
Embedded Erase Algorithm
DQ7#
0
Toggle
Toggle
0
0
No toggle
Toggle
0
0
Standard
Mode
Reading within Erase
Suspended Sector
1
No toggle
0
N/A
Toggle
1
Erase
Suspend Reading within Non-Erase
Data
Data
Data
0
Data
N/A
Data
N/A
1
0
Mode
Suspended Sector
Erase-Suspend-Program
DQ7#
Toggle
Notes:
1. DQ5 switches to ‘1’ when an Embedded Program or Embedded Erase operation has exceeded the maximum timing limits.
See “DQ5: Exceeded Timing Limits” for more information.
2. DQ7 and DQ2 require a valid address when reading status information. Refer to the appropriate subsection for further details.
Am29LV017D
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AMD [ AMD ]
