CAT28C512/513
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.
Toggle Bit
In addition to the
DATA
Polling feature of the CAT28C512/
513, the device offers an additional method for determin-
ing the completion of a write cycle. While a write cycle is
in progress, reading data from the device will result in I/
O
6
toggling between one and zero. However, once the
write is complete, I/O
6
stops toggling and valid data can
be read from the device.
Figure 7. DATA Polling
ADDRESS
CE
WE
tOEH
OE
tWC
I/O7
DIN = X
DOUT = X
D OUT = X
tOE
tOES
Figure 8. Toggle Bit
WE
CE
tOEH
OE
tOE
tOES
I/O6
(1)
tWC
(1)
Note:
(1) Beginning and ending state of I/O
6
is indeterminate.
Doc. No. 1007, Rev. F
8