X28HC64D-50 XICOR [Xicor Inc.], X28HC64D-50 Datasheet - Page 7

• Manufacturer Part Number: X28HC64D-50
• Description: 5 Volt, Byte Alterable E2PROM
• Manufacturer: XICOR [Xicor Inc.]

X28HC64
SOFTWARE DATA PROTECTION
Figure 6. Timing Sequence—Byte or Page Write
Figure 7. Write Sequence for
Software Data Protection
PROTECTED STATE
V CC
WE
RE-ENTERS DATA
CE
0V
WRITE DATA 55
WRITE DATA XX
LAST ADDRESS
WRITE DATA AA
WRITE DATA A0
TO ADDRESS
TO ADDRESS
TO ADDRESS
WRITE LAST
AFTER t WC
ADDRESS
BYTE TO
TO ANY
0AAA
ADDR
1555
1555
DATA
1555
AA
BYTE/PAGE
LOAD ENABLED
OPTIONAL BYTE
OR PAGE WRITE
ALLOWED
0AAA
55
3857 FHD F17
1555
A0
t BLC MAX
7
Regardless of whether the device has previously been
protected or not, once the software data protection
algorithm is used, the X28HC64 will automatically dis-
able further writes unless another command is issued to
deactivate it. If no further commands are issued the
X28HC64 will be write protected during power-down
and after any subsequent power-up.
Note:
WRITES
PAGE
BYTE
Once initiated, the sequence of write operations
should not be interrupted.
OK
OR
t WC
WRITE
PROTECTED
(V CC )
3857 FHD F16