X28LC512/X28LC513
DATA Polling I/O
7
Figure 2a. DATA Polling Bus Sequence
LAST
WRITE
WE
CE
OE
V
IH
V
HIGH Z
OH
I/O
7
V
OL
X28LC512
READY
A –A
0
15
An
An
An
An
An
An
An
3005 ILL F12
Figure 2b. DATA Polling Software Flow
DATA Polling can effectively halve the time for writing to
the X28LC512/513. The timing diagram in Figure 2a
illustrates the sequence of events on the bus. The
softwareflowdiagraminFigure2billustratesonemethod
of implementing the routine.
WRITE DATA
NO
WRITES
COMPLETE?
YES
SAVE LAST DATA
AND ADDRESS
READ LAST
ADDRESS
IO
NO
7
COMPARE?
YES
X28LC512
READY
3005 ILL F13
4