AT29C257-12 ATMEL Corporation, AT29C257-12 Datasheet - Page 8

• Manufacturer Part Number: AT29C257-12
• Description: 256K 32K x 8 5-volt Only CMOS Flash Memory
• Manufacturer: ATMEL Corporation

Software Protected Program Cycle Waveform
Notes for software program code:
1. Data Format: I/O7 - I/O0 (Hex);
2. Data Protect state will be activated at end of program cycle.
3. Data Protect state will be deactivated at end of program
4. 64-bytes of data must be loaded.
Notes: 1. A6 through A14 must specify the page address
Software Data
Protection Enable Algorithm
4-112
Address Format: A14 - A0 (Hex).
period.
2. OE must be high when WE and CE are both low.
during each high to low transition of WE (or CE)
after the software code has been entered.
PAGE (64 BYTES)
ADDRESS 2AAA
ADDRESS 5555
ADDRESS 5555
LOAD DATA AA
LOAD DATA 55
LOAD DATA A0
LOAD DATA
TO
TO
TO
TO
AT29C257
(4)
WRITES ENABLED
ENTER DATA
PROTECT STATE
(1)
(2)
3. All bytes that are not loaded within the page being
Software Data
Protection Disable Algorithm
programmed will be indeterminate.
(1, 2, 3)
PAGE (64 BYTES)
ADDRESS 2AAA
ADDRESS 2AAA
LOAD DATA AA
ADDRESS 5555
ADDRESS 5555
LOAD DATA AA
ADDRESS 5555
ADDRESS 5555
LOAD DATA 55
LOAD DATA 80
LOAD DATA 55
LOAD DATA 20
LOAD DATA
TO
TO
TO
TO
TO
TO
TO
(4)
EXIT DATA
PROTECT STATE
(1)
(3)