AM29F010-55EC Spansion Inc., AM29F010-55EC Datasheet - Page 15

• Manufacturer Part Number: AM29F010-55EC
• Manufacturer: Spansion Inc.

Specifications of AM29F010-55EC

• Lead Free Status / Rohs Status: Not Compliant

DQ6: Toggle Bit I
Toggle Bit I on DQ6 indicates whether an Embedded
Program or Erase algorithm is in progress or complete.
Toggle Bit I may be read at any address, and is valid
after the rising edge of the final WE# pulse in the com-
mand sequence (prior to the program or erase opera-
tion), and during the sector erase time-out.
During an Embedded Program or Erase algorithm op-
eration, successive read cycles to any address cause
DQ6 to toggle. (The system may use either OE# or
CE# to control the read cycles.) When the operation is
complete, DQ6 stops toggling.
After an erase command sequence is written, if all
sectors selected for erasing are protected, DQ6 tog-
gles for approximately 100 s, then returns to reading
array data. If not all selected sectors are protected,
the Embedded Erase algorithm erases the unpro-
tected sectors, and ignores the selected sectors that
are protected.
If a program address falls within a protected sector,
DQ6 toggles for approximately 2 s after the program
command sequence is written, then returns to reading
array data.
The Write Operation Status table shows the outputs for
Toggle Bit I on DQ6. Refer to Figure 4 for the toggle bit
algorithm, and to the Toggle Bit Timings figure in the
“AC Characteristics” section for the timing diagram.
Reading Toggle Bit DQ6
Refer to Figure 4 for the following discussion. When-
ever the system initially begins reading toggle bit sta-
tus, it must read DQ7–DQ0 at least twice in a row to
determine whether a toggle bit is toggling. Typically, a
system would note and store the value of the toggle bit
after the first read. After the second read, the system
would compare the new value of the toggle bit with the
first. If the toggle bit is not toggling, the device has
completed the program or erase operation. The sys-
tem can read array data on DQ7–DQ0 on the following
read cycle.
However, if after the initial two read cycles, the system
determines that the toggle bit is still toggling, the
system also should note whether the value of DQ5 is
high (see the section on DQ5). If it is, the system
should then determine again whether the toggle bit is
toggling, since the toggle bit may have stopped tog-
gling just as DQ5 went high. If the toggle bit is no longer
toggling, the device has successfully completed the
program or erase operation. If it is still toggling, the
device did not complete the operation successfully, and
the system must write the reset command to return to
reading array data.
The remaining scenario is that the system initially de-
termines that the toggle bit is toggling and DQ5 has not
Am29F010
Notes:
1. Read toggle bit twice to determine whether or not it is
2. Recheck toggle bit because it may stop toggling as DQ5
gone high. The system may continue to monitor the
toggle bit and DQ5 through successive read cycles, de-
termining the status as described in the previous para-
graph. Alternatively, it may choose to perform other
system tasks. In this case, the system must start at the
beginning of the algorithm when it returns to determine
the status of the operation (top of Figure 4).
toggling. See text.
changes to “1”. See text.
No
Figure 4. Toggle Bit Algorithm
Reset Command
Complete, Write
Read DQ7–DQ0
Read DQ7–DQ0
Read DQ7–DQ0
Program/Erase
Operation Not
Toggle Bit
Toggle Bit
DQ5 = 1?
= Toggle?
= Toggle?
START
Twice
Yes
Yes
Yes
(Notes
1, 2)
1
Operation Complete
No
No
Program/Erase
16736G-10
15