X28C256D Xicor, X28C256D Datasheet - Page 5

• Manufacturer Part Number: X28C256D
• Description: 5 Volt/ Byte Alterable E2PROM
• Manufacturer: Xicor

X28C256
THE TOGGLE BIT I/O
Figure 4. Toggle Bit Bus Sequence
Figure 5. Toggle Bit Software Flow
I/O 6
WE
OE
CE
WRITE
* Beginning and ending state of I/O 6 will vary.
LAST
FROM ADDR n
LOAD ACCUM
ACCUM WITH
LAST WRITE
COMPARE
COMPARE
X28C256
ADDR n
READY
OK?
6
YES
*
NO
V OH
3855 FHD F15
V OL
5
The Toggle Bit can eliminate the software housekeeping
chore of saving and fetching the last address and data
written to a device in order to implement DATA Polling.
This can be especially helpful in an array comprised of
multiple X28C256 memories that is frequently updated.
The timing diagram in Figure 4 illustrates the sequence
of events on the bus. The software flow diagram in
Figure 5 illustrates a method for polling the Toggle Bit.
HIGH Z
*
X28C256
READY
3855 FHD F14