A d v a n c e I n f o r m a t i o n
START
Read DQ7–DQ0
(Note 1)
Read DQ7–DQ0
No
Toggle Bit
= Toggle?
Yes
No
DQ5 = 1?
Yes
(Notes
1,2)
Read DQ7–DQ0
Twice
Toggle Bit
= Toggle?
No
Yes
Program/Erase
Operation Not
Complete, Write
Reset Command
Program/Erase
Operation Complete
Notes:
1. Read toggle bit twice to determine whether or not it
is toggling. See text.
2. Recheck toggle bit because it may stop toggling as
DQ5 changes to 1. See text.
Figure 7. Toggle Bit Algorithm
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 pro-
gram 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 pre-
viously programmed to 0. Only an erase operation can change a 0 back to a 1. Under this
June 13, 2005 S29AL032D_00_A3
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SPANSION [ SPANSION ]
