8
AT28BV256
0273H–PEEPR–10/04
Programming Algorithm
(1)(2)(3)
Notes: 1. Data Format: I/O7 - I/O0 (Hex); Address Format: A14 - A0 (Hex).
2. Data protect state will be re-activated at the end of program cycle.
3. 1 to 64 bytes of data are loaded.
Software Protected Program Cycle Waveforms
(1)(2)(3)
Notes: 1. A0 - A14 must conform to the addressing sequence for the first three bytes as shown above.
2. A6 through A14 must specify the same page address during each high to low transition of WE
(or CE) after the software
code has been entered.
3. OE
must be high only when WE and CE are both low.
Page Mode Characteristics
Symbol Parameter Min Max Units
t
WC
Write Cycle Time 10 ms
t
AS
Address Set-up Time 0 ns
t
AH
Address Hold Time 50 ns
t
DS
Data Set-up Time 50 ns
t
DH
Data Hold Time 0 ns
t
WP
Write Pulse Width 200 ns
t
BLC
Byte Load Cycle Time 150 µs
t
WPH
Write Pulse Width High 100 ns
LOAD DATA AA
TO
ADDRESS 5555
LOAD DATA 55
TO
ADDRESS 2AAA
LOAD DATA A0
TO
ADDRESS 5555
LOAD DATA XX
TO
ANY ADDRESS
(3)
LOAD LAST BYTE
TO
LAST ADDRESS
(3)
ENTER DATA
PROTECT STATE
WRITES ENABLED
(2)
t
AS
t
AH
t
WP
t
WPH
t
BLC
t
DH
t
WC
t
DS
