X28LC512 Datasheet, PDF (7/19 Pages) Xicor Inc. – 3.3 Volt, Byte Alterable E2PROM

X28LC512/X28LC513
Software Data Protection
Figure 4a. Timing Sequence—Software Data Protect Enable Sequence followed by Byte or Page Write
VCC
0V
DATA
ADDR
CE
AA
5555
55
2AAA
WE
A0
5555
≤tBLC _MAX
WRITES
OK
tWC
BYTE
OR
PAGE
(VCC)
WRITE
PROTECTED
NOTE: All other timings and control pins are per page write timing requirements.
3005 ILL F16
Figure 4b. Write Sequence for Software Data
Protection
WRITE DATA AA
TO ADDRESS
5555
WRITE DATA 55
TO ADDRESS
2AAA
WRITE DATA A0
TO ADDRESS
5555
Regardless of whether the device has previously been
protected or not, once the software data protected
algorithm is used and data has been written, the
X28LC512/513 will automatically disable further writes
unless another command is issued to cancel it. If no
further commands are issued the X28LC512/513 will be
write protected during power-down and after any subse-
quent power-up. The state of A₁₅ while executing the
algorithm is don’t care.
Note: Once initiated, the sequence of write operations
should not be interrupted.
WRITE DATA XX
TO ANY
ADDRESS
WRITE LAST
BYTE TO
LAST ADDRESS
OPTIONAL
BYTE/PAGE
LOAD OPERATION
AFTER tWC
RE-ENTERS DATA
PROTECTED STATE
3005 FHD F17
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