AT29C040 ATMEL Corporation, AT29C040 Datasheet - Page 8

• Manufacturer Part Number: AT29C040
• Description: 4-Megabit 512K x 8 5-volt Only 256-Byte Sector CMOS Flash Memory
• Manufacturer: ATMEL Corporation

Notes: 1. A8 through A18 must specify the sector address
Software Data
Protection Enable Algorithm
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. 256-bytes of data
8
Software Protected Program Cycle Waveform
Address Format: A14 - A0 (Hex).
period.
during each high to low transition of WE (or CE) after
the software code has been entered.
SECTOR (256 BYTES)
ADDRESS 2AAA
LOAD DATA AA
ADDRESS 5555
ADDRESS 5555
LOAD DATA A0
LOAD DATA 55
LOAD DATA
MUST BE
AT29C040A
TO
TO
TO
TO
loaded.
(4)
WRITES ENABLED
ENTER DATA
PROTECT STATE
(1)
(2)
Software Data
Protection Disable Algorithm
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.
(1, 2, 3)
SECTOR (256 BYTES)
ADDRESS 2AAA
ADDRESS 2AAA
ADDRESS 5555
ADDRESS 5555
ADDRESS 5555
ADDRESS 5555
LOAD DATA AA
LOAD DATA AA
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)