AT29C512 Datasheet, PDF (11/18 Pages) ATMEL Corporation – 512K 64K x 8 5-volt Only CMOS Flash Memory

18. Software Data Protection
Enable Algorithm⁽¹⁾
LOAD DATA AA
TO
ADDRESS 5555
AT29C512
19. Software Data Protection
Disable Algorithm⁽¹⁾
LOAD DATA AA
TO
ADDRESS 5555
LOAD DATA 55
TO
ADDRESS 2AAA
LOAD DATA 55
TO
ADDRESS 2AAA
LOAD DATA A0
TO
ADDRESS 5555
WRITES ENABLED
LOAD DATA 80
TO
ADDRESS 5555
LOAD DATA
TO
PAGE (128 BYTES)⁽⁴⁾
ENTER DATA
PROTECT STATE⁽²⁾
LOAD DATA AA
TO
ADDRESS 5555
LOAD DATA 55
TO
ADDRESS 2AAA
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 pro-
gram period.
4. 128 bytes of data MUST BE loaded.
LOAD DATA 20
TO
ADDRESS 5555
EXIT DATA
PROTECT STATE⁽³⁾
LOAD DATA
TO
PAGE (128 BYTES)⁽⁴⁾
20. Software Protected Program Cycle Waveform^(1)(2)(3)
OE ⁽¹⁾
CE
t_WP
t_WPH
t_BLC
WE
t_AS
t_AH
t_DH
A0-A6
BYTE ADDRESS
Notes:
A7-A15 ⁽²⁾
DATA ⁽³⁾
5555
2AAA
t_DS
AA
55
5555
SECTOR ADDRESS
A0
BYTE 0
BYTE 126
BYTE 127
t_WC
1. A7 through A15 must specify the page 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.
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0456H–FLASH–2/05