AT28HC256E ATMEL Corporation, AT28HC256E Datasheet - Page 8

• Manufacturer Part Number: AT28HC256E
• Description: 256 32K x 8 High Speed Parallel EEPROMs
• Manufacturer: ATMEL Corporation

Software Data Protection
Enable Algorithm
Notes for software program code:
Software Protected Write Cycle Waveforms
Notes:
8
1. Data Format: I/O7 - I/O0 (Hex);
2. Write Protect state will be activated at end of
3. Write Protect state will be deactivated at end of
4. 1 to 64 bytes of data are loaded.
1. A6 through A14 must specify the same page address during each high to low transition of WE (or CE) after the software
2. OE must be high only when WE and CE are both low.
Address Format: A14 - A0 (Hex).
write even if no other data is loaded.
write period even if no other data is loaded.
code has been entered.
LOAD LAST BYTE
ANY ADDRESS
ADDRESS 2AAA
LAST ADDRESS
LOAD DATA AA
ADDRESS 5555
LOAD DATA A0
ADDRESS 5555
LOAD DATA XX
LOAD DATA 55
TO
TO
TO
TO
TO
AT28HC256
(1)
(4)
WRITES ENABLED
ENTER DATA
PROTECT STATE
(2)
Software Data Protection
Disable Algorithm
(1)(2)
LOAD LAST BYTE
ANY ADDRESS
ADDRESS 2AAA
ADDRESS 2AAA
LAST ADDRESS
LOAD DATA AA
ADDRESS 5555
ADDRESS 5555
LOAD DATA AA
ADDRESS 5555
ADDRESS 5555
LOAD DATA XX
LOAD DATA 55
LOAD DATA 80
LOAD DATA 55
LOAD DATA 20
TO
TO
TO
TO
TO
TO
TO
TO
(1)
(4)
EXIT DATA
PROTECT STATE
(3)