S7760A Datasheet, PDF (23/54 Pages) Seiko Instruments Inc – PROGRAMMABLE PORT CONTROLLER (PORT EXPANDER WITH BUILT-IN E2PROM CIRCUIT)

PROGRAMMABLE PORT CONTROLLER (PORT EXPANDER WITH BUILT-IN E²PROM CIRCUIT)
Rev.2.0_01
S-7760A
4. Acknowledgment
Data is transmitted sequentially in 8-bit. Changing the SDA line to “L” indicates that the devices on the system bus
have received data, thus the devices send an acknowledgment signal back during the 9th clock of cycle.
The S-7760A does not send an acknowledgment signal back during the Write operation.
SCL
Input
1
8
9
SDA
(Master device’s
output)
SDA
Output
Start
Condition
Figure 25 Acknowledgment Output Timing
Acknowledgment
signal output
5. Read operation
When this IC receives the 7-bit device address and the Read/Write instruction code “1” after receiving a start condition,
it generates an acknowledgment signal.
Next, data with 8-bit length is output from this IC synchronizing with the SCL clock.
After that, the master device sends a stop condition, not an acknowledgment signal in order to finish the Read
operation.
S
T
R
A
E
R
A
T
DEVICE
D
ADDRESS
NO ACK from
Master Device
S
T
O
P
SDA LINE
DDD
C
2
C
1
C
0
C3 C2 C1 C0
1
B7 B6 B5 B4 B3 B2 B1 B0
M
S
LR A
S/ C
DATA
B
BW K
Figure 26 Read
23