S29AS008J Datasheet, PDF (39/55 Pages) SPANSION – 8 Megabit (1M x 8-Bit / 512K x 16-Bit) CMOS 1.8 Volt-Only Boot Sector Flash Memory

Data Sheet
12.6
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
programmed 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 exceeded the timing limits, DQ5 produces a 1.
Under both these conditions, the system must issue the reset command to return the device to reading array
data.
12.7
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 additional
sectors are selected for erasure, the entire time-out also applies after each additional sector erase command.
When the time-out is complete, DQ3 switches from 0 to 1. The system may ignore DQ3 if the system can
guarantee that the time between additional sector erase commands will always be less than 50 μs. See
also Sector Erase Command Sequence on page 31.
After the sector erase command sequence is written, the system should read the status on DQ7 (Data#
Polling) or DQ6 (Toggle Bit I) to ensure the device has accepted the command sequence, and then read
DQ3. If DQ3 is 1, the internally controlled erase cycle has begun; 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 accepted. Table 12.1 shows the outputs for DQ3.
Table 12.1 Write Operation Status
Operation
DQ7
(Note 2)
DQ6
DQ5
(Note 1)
DQ3
DQ2
(Note 2)
RY/BY#
Standard ^{Embedded Program Algorithm}
DQ7#
Toggle
0
Mode
Embedded Erase Algorithm
0
Toggle
0
N/A
No toggle
0
1
Toggle
0
Erase
Suspend
Mode
Reading within Erase
Suspended Sector
Reading within Non-Erase
Suspended Sector
1
No toggle
0
N/A
Toggle
1
Data
Data
Data
Data
Data
1
Erase-Suspend-Program
DQ7#
Toggle
0
N/A
N/A
0
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 on page 39 for more information.
2. DQ7 and DQ2 require a valid address when reading status information. Refer to the appropriate subsection for further details.
November 9, 2011 S29AS008J_00_09
S29AS008J
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