Softwar e Protected Write Cycle Waveforms
(1, 2)
Notes: 1. A6 through A14 must specify the same page address during each high to low transition of
WE (or CE) after
the software cod e ha s been ent ered.
2.
OE must be high only when WE and CE are both low.
LOAD LAST BYTE
TO
LAST ADDRE SS
LOAD DATA A0
TO
ADDRESS 5555
LOAD DATA 55
TO
ADDRESS 2AAA
LOAD DATA AA
TO
ADDRESS 5555
Notes for software program code:
1. Data Format : I/O7 - I/O0 (Hex );
Addre ss Format : A14 - A0 (Hex).
2. Writ e Prot ec t st ate will be act iv ated at en d of wri te eve n if no
other data is loaded.
3. Writ e Prot ec t st ate will be dea ctivat ed at en d of write period
even if no other da ta is lo aded .
4. 1 to 64-bytes of data are loaded.
ENTER DA TA
PROTECT STATE
WRITES ENABLED
(2)
Software Data
Protection E nabl e
Algorit hm
(1)
LOAD DATA XX
TO
ANY ADDRESS
(4)
LOAD LAST BYTE
TO
LAST ADDRE SS
LOAD DA TA 55
TO
ADDRESS 2AAA
LOAD DATA AA
TO
ADDRESS 5555
LOAD DA TA 80
TO
ADDRESS 5555
LOAD DA TA 55
TO
ADDRESS 2AAA
LOAD DATA AA
TO
ADDRESS 5555
LOAD DA TA 20
TO
ADDRESS 5555
EXIT DATA
PROTECT STATE
(3)
Software Data
Prot ec ti on Di s abl e
Algorit hm
(1)
LOAD DATA XX
TO
ANY ADDRESS
(4)
2-224 AT28C256
