X28C512/X28C513
Resetting Software Data Protection
Figure 5a. Reset Software Data Protection Timing Sequence
V
CC
STANDARD
OPERATING
MODE
DATA
AA
55
2AAA
80
5555
AA
5555
55
2AAA
20
5555
≥t
WC
ADDR 5555
CE
WE
NOTE: All other timings and control pins are per page write timing requirements.
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Figure 5b. Software Sequence to Deactivate
Software Data Protection
In the event the user wants to deactivate the software
data protection feature for testing or reprogramming in
an E PROM programmer, the following six step algo-
WRITE DATA AA
TO ADDRESS
5555
2
rithm will reset the internal protection circuit. After t
,
WC
the X28C512/513 will be in standard operating mode.
Note: Once initiated, the sequence of write operations
should not be interrupted.
WRITE DATA 55
TO ADDRESS
2AAA
WRITE DATA 80
TO ADDRESS
5555
WRITE DATA AA
TO ADDRESS
5555
WRITE DATA 55
TO ADDRESS
2AAA
WRITE DATA 20
TO ADDRESS
5555
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8
XICOR [ XICOR INC. ]
