P r e l i m i n a r y
START
Read DQ7–DQ0
Read DQ7–DQ0
No
Toggle Bit
= Toggle?
Yes
No
DQ5 = 1?
Yes
Read DQ7–DQ0
Twice
Toggle Bit
= Toggle?
No
Yes
Program/Erase
Operation Not
Program/Erase
Complete, Write
Reset Command
Operation Complete
Note: The system should recheck the toggle bit even if DQ5 = “1” because the toggle
bit may stop toggling as DQ5 changes to “1.” See the subsections on DQ6 and DQ2
for more information.
Figure 5. Toggle Bit Algorithm
DQ2: Toggle Bit II
The “Toggle Bit II” on DQ2, when used with DQ6, indicates whether a particular
sector is actively erasing (that is, the Embedded Erase algorithm is in progress),
or whether that sector is erase-suspended. Toggle Bit II is valid after the rising
edge of the final WE# pulse in the command sequence.
DQ2 toggles when the system reads at addresses within those sectors that have
been selected for erasure. But DQ2 cannot distinguish whether the sector is ac-
tively erasing or is erase-suspended. DQ6, by comparison, indicates whether the
device is actively erasing, or is in Erase Suspend, but cannot distinguish which
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Am29BDS320G
27243B1 October 1, 2003
SPANSION [ SPANSION ]
