CAT28LV256
DATA
Polling
DATA
polling is provided to indicate the completion of
write cycle. Once a byte write or page write cycle is
initiated, attempting to read the last byte written will
output the complement of that data on I/O
7
(I/O
0
–I/O
6
are indeterminate) until the programming cycle is com-
plete. Upon completion of the self-timed write cycle, all
I/O’s will output true data during a read cycle.
Figure 7. DATA Polling
ADDRESS
Toggle Bit
In addition to the
DATA
Polling feature, the device can
determine the completion of a write cycle, while a write
cycle is in progress, by reading data from the device.
This results in I/O
6
toggling between one and zero. Once
the write is complete, however, I/O
6
stops toggling and
valid data can be read from the device.
CE
WE
tOEH
OE
tWC
I/O7
DIN = X
DOUT = X
DOUT = X
28LV256 F10
tOE
tOES
Figure 8. Toggle Bit
WE
CE
tOEH
OE
tOE
tOES
I/O6
(1)
tWC
(1)
28LV256 F11
Note:
(1) Beginning and ending state of I/O
6
is indeterminate.
Doc. No. 25040-00 4/01 P-1
8
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