Rainbow Electronics AT29C040A - Manual (Page 10)

10
AT29C040A
0333I–FLASH–05/02
Software Data Protection
Enable Algorithm
(1)
Notes: 1. Data Format: I/O7 - I/O0 (Hex);
Address Format: A14 - A0 (Hex).
2. Data Protect state will be activated at end of
program cycle.
3. Data Protect state will be deactivated at end of
program period.
4. 256 bytes of data MUST BE loaded.
LOAD DATA AA
TO
ADDRESS 5555
LOAD DATA 55
TO
ADDRESS 2AAA
LOAD DATA A0
TO
ADDRESS 5555
LOAD DATA
TO
PAGE (256 BYTES) (4)
WRITES ENABLED
ENTER DATA
PROTECT STATE (2)
Software Data Protection
Disable Algorithm
(1)
LOAD DATA AA
TO
ADDRESS 5555
LOAD DATA 55
TO
ADDRESS 2AAA
LOAD DATA 80
TO
ADDRESS 5555
LOAD DATA AA
TO
ADDRESS 5555
LOAD DATA 55
TO
ADDRESS 2AAA
LOAD DATA 20
TO
ADDRESS 5555
LOAD DATA
TO
PAGE (256 BYTES) (4)
EXIT DATA
PROTECT STATE (3)
Software Protected Program Cycle Waveform
(1)(2)(3)
Notes: 1. A8 through A18 must specify the sector address during each high to low transition of WE (or CE) after the software code
has been entered.
2. OE must be high when WE and CE are both low.
3. All bytes that are not loaded within the sector being programmed will be indeterminate.