S-24CM01C Datasheet, PDF (14/32 Pages) Seiko Instruments Inc – Write protect function during the low power supply voltage

2-WIRE SERIAL E²PROM
S-24CM01C
Rev.2.0_02_S
6. 3 Write protect
Write protect is available in the S-24CM01C. When the WP pin is connected to the VCC, write operation to memory
area is inhibited.
When the WP pin is connected to GND or set in open, the write protect is invalid, and write operation in all
memory area is available.
Fix the level of the WP pin from start condition in the write operation (byte write, page write) until stop condition. If
the WP pin changes during this time, the address data being written at this time is not guaranteed. Regarding the
timing of write protect, refer to Figure 5.
In not using the write protect, connect the WP pin to GND or set it open. The write protect is valid in the range of
operation power supply voltage.
As seen in Figure 13 when the write protect is valid, the S-24CM01C does not generate an acknowledgment
signal after data input.
S
W
T
R
A
I
R
DEVICE
T
UPPER
T
ADDRESS E
WORD ADDRESS
LOWER WORD
ADDRESS
S
T
O
DATA
P
SDA LINE
1 0 1 0 A2 A1 P0 0 _{W15 W14 W13 W12 W11 W10 W9 W8 W7 W6 W5 W4 W3 W2 W1 W0 D7 D6 D5 D4 D3 D2 D1 D0}
M
LR A
A
A
N
S
S/ C
C
C
A
B
BW K
K
K
C
K
WP
Figure 13 Write Protect
14