Rev. 1.0, 02/00, page 489 of 1141
23.3
Operation
23.3.1
I
2
C Bus Data Format
The I
2
C bus interface has serial and I
2
C bus formats.
The I
2
C bus formats are addressing formats with an acknowledge bit. These are shown in figures
23.3(1) and (2). The first frame following a start condition always consists of 8 bits. Formatless
transfer can be selected only for IIC channel 0. The formatless transfer data is shown in figure
23.3 (3).
The serial format is a non-addressing format with no acknowledge bit. This is shown in figure
23.4.
Figure 23.5 shows the I
2
C bus timing.
The symbols used in figures 23.3 to 23.5 are explained in table 23.4.
S
A
SLA
7
n
R/W
DATA
A
1
1
m
1
1
1
A/A
1
P
1
Transfer bit count
(n = 1 to 8)
Transfer frame count
(m = 1 or above)
S
SLA
7
n1
7
R/W
A
DATA
1
1
1
m1
1
A/A
1
S
1
SLA
R/W
1
1
m2
A
1
DATA
n2
A/A
1
P
1
Upper: Transfer bit count (n1 and N2 = 1 to 8)
Lower: Transfer frame count (m1 and m2 = 1 or above)
(1) FS = 0 or FSX = 0
A
n
DATA
DATA
A
1
m
1
8
1
A/A
1
Transfer bit count
(n = 1 to 8)
Transfer frame count
(m = 1 or above)
(3) Formatless (IIC channel 0 only, FS = 0 or FSX = 0)
(2) Start condition transmission, FS = 0 or FSX = 0
Figure 23.3 I
2
C Bus Data Formats (I
2
C Bus Formats)