X28C64 Datasheet, PDF (7/25 Pages) Xicor Inc. – 5 Volt, Byte Alterable E2PROM

X28C64
Software Data Protection
Figure 6. Timing Sequence—Byte or Page Write
VCC
0V
DATA AA
ADDRESS 1555
CE
55
0AAA
WE
A0
1555
tWPH2
tWC
WRITES
OK
≤tBLC _MAX
BYTE
OR
PAGE
(VCC)
WRITE
PROTECTED
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Figure 7. Write Sequence for Software Data
Protection
WRITE DATA AA
TO ADDRESS
1555
WRITE DATA 55
TO ADDRESS
0AAA
WRITE DATA A0
TO ADDRESS
1555
WRITE DATA XX
TO ANY
ADDRESS
BYTE/PAGE
LOAD ENABLED
Regardless of whether the device has previously been
protected or not, once the software data protection
algorithm is used and data has been written, the X28C64
will automatically disable further writes unless another
command is issued to cancel it. If no further commands
are issued the X28C64 will be write protected during
power-down and after any subsequent power-up.
Note: Once initiated, the sequence of write operations
should not be interrupted.
WRITE LAST
BYTE TO
LAST ADDRESS
AFTER tWC
RE-ENTERS DATA
PROTECTED STATE
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3853 FHD F17
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