X28C256D-20 XICOR [Xicor Inc.], X28C256D-20 Datasheet - Page 4

• Manufacturer Part Number: X28C256D-20
• Description: 5 Volt, Byte Alterable E2PROM
• Manufacturer: XICOR [Xicor Inc.]

X28C256
DATA POLLING I/O
Figure 2. DATA Polling Bus Sequence
Figure 3. DATA Polling Software Flow
A 0 –A 14
I/O 7
WE
OE
CE
SAVE LAST DATA
AND ADDRESS
WRITE
WRITE DATA
LAST
COMPLETE?
READ LAST
COMPARE?
ADDRESS
V IH
X28C256
An
WRITES
READY
IO 7
7
YES
YES
An
NO
HIGH Z
NO
An
3855 FHD F13
V OL
An
4
DATA Polling can effectively halve the time for writing to
the X28C256. The timing diagram in Figure 2 illustrates
the sequence of events on the bus. The software flow
diagram in Figure 3 illustrates one method of implement-
ing the routine.
An
An
An
V OH
X28C256
READY
3855 FHD F12