BAT32G1x9 user manual | Chapter 19 Universal serial communication unit
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Rev.1.02
Table 19-5 Selection of simple I
2C
operating clocks
SMRmn
register
SPSm register
Running Clock (fMCK) Note
CKSmn
PRS
m13
PRS
m12
PRS
m11
PRS
m10
PRS
m03
PRS
m02
PRS
m01
PRS
m00
fCLK=32MHz runtime
0
X
X
X
X
0
0
0
0
fCLK
32MHz
X
X
X
X
0
0
0
1
fCLK/2
16MHz
X
X
X
X
0
0
1
0
fCLK/22
8MHz
X
X
X
X
0
0
1
1
fCLK/23
4MHz
X
X
X
X
0
1
0
0
fCLK/24
2MHz
X
X
X
X
0
1
0
1
fCLK/25
1MHz
X
X
X
X
0
1
1
0
fCLK/26
500kHz
X
X
X
X
0
1
1
1
fCLK/27
250kHz
X
X
X
X
1
0
0
0
fCLK/28
125kHz
X
X
X
X
1
0
0
1
fCLK/29
62.5kHz
X
X
X
X
1
0
1
0
fCLK/210
31.25kHz
X
X
X
X
1
0
1
1
fCLK/211
15.63kHz
1
0
0
0
0
X
X
X
X
fCLK
32MHz
0
0
0
1
X
X
X
X
fCLK/2
16MHz
0
0
1
0
X
X
X
X
fCLK/22
8MHz
0
0
1
1
X
X
X
X
fCLK/23
4MHz
0
1
0
0
X
X
X
X
fCLK/24
2MHz
0
1
0
1
X
X
X
X
fCLK/25
1MHz
0
1
1
0
X
X
X
X
fCLK/26
500kHz
0
1
1
1
X
X
X
X
fCLK/27
250kHz
1
0
0
0
X
X
X
X
fCLK/28
125kHz
1
0
0
1
X
X
X
X
fCLK/29
62.5kHz
1
0
1
0
X
X
X
X
fCLK/210
31.25kHz
1
0
1
1
X
X
X
X
fCLK/211
15.63kHz
Other than the above
Disable settings.
NoteWhen you change the clock selected as f
CLK
(change the value of the system clock control register (CKC)), you
must stop the operation of the Universal Serial Communication Unit
(SCI)
(serial channel stop register
m
(STm)=000FH) after making changes.
Note 1.X: Ignore
2.m:unit number(m=0~2)n:channel number(n=0~3)mn=00~03, 10~11, 20~21
An example of the I2C transfer rate at f
MCK
=f
CLK
=32MHz is shown below.
I
2
C transfer mode
(Expected transfer
rate)
f
CLK
=32MHz
Running Clock (f
MCK
).
SDRmn[15:9]
Calculated transfer rate
Error with the expected
transfer rate
100kHz
f
CLK
/2
79
100kHz
0.0%
400kHz
f
CLK
41
380kHz
5.0%
note
1MHz
f
CLK
18
0.84MHz
16.0%
note
Note That because the duty cycle of the
SCL
signal is
50%,
the error cannot be set to
about
"0"%.