XM28C040 Datasheet, PDF (7/17 Pages) Xicor Inc. – 5 Volt, Byte Alterable E2PROM

XM28C040
SOFTWARE DATA PROTECTION
Figure 6. Timing Sequence—Byte or Page Write
VCC
0V
DATA
ADDR.
A0–A16*
CE
AA
5555
55
2AAA
WE
A0
5555
≤tBLC _MAX
*A17 & A18 select one of four devices on the module.
tWC
WRITES
OK
BYTE
OR
PAGE
(VCC)
WRITE
PROTECTED
3873 FHD F14
Figure 7. Write Sequence for
Software Data Protection
WRITE DATA AA
TO ADDRESS
5555
WRITE DATA 55
TO ADDRESS
2AAA
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 device
will automatically disable further writes unless another
command is issued to cancel it. If no further commands
are issued the device will be write protected during
power-down and after any subsequent power-up.
WRITE DATA A0
TO ADDRESS
5555
WRITE DATA XX
TO ANY
ADDRESS
BYTE/PAGE
LOAD ENABLED
WRITE LAST
BYTE TO
LAST ADDRESS
AFTER tWC
RE-ENTERS DATA
PROTECTED STATE
3873 FHD F15
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