S-93C46B Datasheet, PDF (19/45 Pages) Seiko Instruments Inc – CMOS SERIAL E2PROM

Rev.4.3_00
CMOS SERIAL E²PROM
S-93C46B/56B/66B
5. Write enable (EWEN) and write disable (EWDS)
The EWEN instruction is an instruction that enables a write operation. The status in which a write
operation is enabled is called the program enable mode.
The EWDS instruction is an instruction that disables a write operation. The status in which a write
operation is disabled is called the program disable mode.
After CS goes high, input an instruction in the order of the start bit, EWEN or EWDS instruction, and
address (optional). Each mode becomes valid by inputting a low level to CS after the last address
(optional) has been input.
CS
Standby
SK
1 2 3 4 5 6 7 89
DI
<1> 0
0
11 = EWEN
4Xs
00 = EWDS
Figure 18 Write Enable/Disable Timing (S-93C46B)
CS
Standby
SK
1 2 3 4 5 6 7 8 9 10 11
DI
<1> ⁰
0
11 = EWEN
6Xs
00 = EWDS
Figure 19 Write Enable/Disable Timing (S-93C56B, S-93C66B)
(1) Recommendation for write operation disable instruction
It is recommended to implement a design that prevents an incorrect write operation when a write
instruction is erroneously recognized by executing the write operation disable instruction when
executing instructions other than write instruction, and immediately after power-on and before
power off.
Seiko Instruments Inc.
19