R01UH0822EJ0100 Rev.1.00
Page 756 of 1041
Jul 31, 2019
RX13T Group
24. I
2
C-bus Interface (RIICa)
24.3
Operation
24.3.1
Communication Data Format
The I
2
C-bus format consists of 8-bit data and 1-bit acknowledge. The first byte following a start condition or restart
condition is an address byte used to specify a slave device with which the master device communicates. The specified
slave is valid until a new slave is specified or a stop condition is issued.
shows the I
2
C-bus format, and
2
C-bus timing.
Figure 24.3
I
2
C-bus Format
Figure 24.4
I
2
C-bus Timing (SLA = 7 Bits)
S:
Start condition. The master device drives the SDA0 line low from high level while the SCL0 line is at a high level.
SLA:
Slave address, by which the master device selects a slave device.
R/W#: Indicates the direction of data transfer: from the slave device to the master device when R/W is 1, or from the master device to
the slave device when R/W is 0.
A:
Acknowledge. The receive device drives the SDA0 line low. (In master transmit mode, the slave device returns acknowledge.
In master receive mode, the master device returns acknowledge.)
A#:
Not Acknowledge. The receive device drives the SDA0 line high.
Sr:
Restart condition. The master device drives the SDA0 line low from the high level after the setup time has elapsed with the
SCL0 line at the high level.
DATA: Transmitted or received data
P:
Stop condition. The master device drives the SDA0 line high from low level while the SCL0 line is at a high level.
[7-bit address format]
S
R/W# A
A
A/A#
P
S
SLA (7 bits)
W#
A
A
A/A#
P
SLA (8 bits)
SLA(2 bits)
DATA (8 bits)
A
S
W#
A
A
A/A#
P
SLA (8 bits)
SLA(2 bits)
A
Sr SLA(2 bits) R
DATA (8 bits)
1
7
1
1
1
1
1
8
A
DATA (8 bits)
1
7
1
1
1
1
1
8
1
1
1
8
1
8
1
7
1
1
1
8
1
1
7
1
[10-bit address format]
n (n = 1 or more)
n (n = 1 or more)
n (n = 1 or more)
n: Number of transmit DATA bytes
1 to 7
8
9
1 to 7
8
9
1 to 7
8
9
S
SLA
R/W#
A
Data
A
Data
A
P
SCL0
SDA0