W29C020 Datasheet, PDF (6/21 Pages) Winbond – 256K X 8 CMOS FLASH MEMORY

W29C020
Command Codes for Software Data Protection
BYTE SEQUENCE
TO ENABLE PROTECTION
ADDRESS
DATA
0 Write
1 Write
2 Write
3 Write
4 Write
5 Write
5555H
2AAAH
5555H
-
-
-
AAH
55H
A0H
-
-
-
TO DISABLE PROTECTION
ADDRESS
DATA
5555H
AAH
2AAAH
55H
5555H
80H
5555H
AAH
2AAAH
55H
5555H
20H
Software Data Protection Acquisition Flow
Software Data Protection
Enable Flow
Load data AA
to
address 5555
Software Data Protection
Disable Flow
Load data AA
to
address 5555
Load data 55
to
address 2AAA
Load data 55
to
address 2AAA
Load data A0
to
address 5555
Load data 80
to
address 5555
(Optional page-load
operation)
Sequentially load
up to 128 bytes
of page data
Pause 10 mS
Load data AA
to
address 5555
Load data 55
to
address 2AAA
Exit
Load data 20
to
address 5555
Pause 10 mS
Exit
Notes for software program code:
Data Format: DQ7−DQ0 (Hex)
Address Format: A14−A0 (Hex)
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