X28C512 Xicor, X28C512 Datasheet - Page 7

• Manufacturer Part Number: X28C512
• Description: 5 Volt/ Byte Alterable E2PROM
• Manufacturer: Xicor

X28C512/X28C513
Software Data Protection
Figure 4a. Timing Sequence—Software Data Protect Enable Sequence followed by Byte or Page Write
Figure 4b. Write Sequence for Software Data
Protection
V CC
WE
CE
0V
PROTECTED STATE
RE-ENTERS DATA
WRITE DATA 55
WRITE DATA AA
WRITE DATA XX
LAST ADDRESS
WRITE DATA A0
TO ADDRESS
TO ADDRESS
TO ADDRESS
WRITE LAST
AFTER t WC
NOTE: All other timings and control pins are per page write timing requirements.
ADDRESS
ADDR
DATA
BYTE TO
TO ANY
2AAA
5555
5555
5555
AA
OPTIONAL
BYTE/PAGE
LOAD OPERATION
2AAA
55
3856 FHD F12
5555
A0
t BLC MAX
7
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
X28C512/513 will automatically disable further writes
unless another command is issued to cancel it. If no
further commands are issued the X28C512/513 will be
write protected during power-down and after any subse-
quent power-up. The state of A
algorithm is don’t care.
Note: Once initiated, the sequence of write operations
WRITES
PAGE
BYTE
OK
OR
should not be interrupted.
t WC
WRITE
PROTECTED
15
while executing the
(V CC )
3856 FHD F11