X28C512 Datasheet, PDF (5/25 Pages) Xicor Inc. – 5 Volt, Byte Alterable E2PROM

X28C512/X28C513
The Toggle Bit I/O₆
Figure 3a. Toggle Bit Bus Sequence
LAST
WE ^WRITE
CE
OE
I/O6
VOH
*
VOL
* Beginning and ending state of I/O6 will vary.
Figure 3b. Toggle Bit Software Flow
LAST WRITE
LOAD ACCUM
FROM ADDR n
COMPARE
ACCUM WITH
ADDR n
COMPARE
OK?
YES
X28C512
READY
NO
3856 FHD F10
HIGH Z
*
X28C512/513
READY
3856 FHD F09.1
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 X28C512/513 memories that is frequently up-
dated. Toggle Bit Polling can also provide a method for
status checking in multiprocessor applications. The
timing diagram in Figure 3a illustrates the sequence of
events on the bus. The software flow diagram in Figure
3b illustrates a method for polling the Toggle Bit.
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