16.12 Examples of CAN Baud Rate Setting
The CAN bus requires very accurate timing especially for high baud rates. It is recommended to use only an external crystal
for CAN operations.
(Refer to Section 16.4.2 “Bit Timing” on page 147 and Section 16.4.3 “Baud Rate” on page 148 for timing description and
Section 16.10.8 “CAN Bit Timing Register 1 - CANBT1” on page 163 to Section 16.10.10 “CAN Bit Timing Register 3 -
CANBT3” on page 164 for “CAN Bit Timing Registers”).
Table 16-2. Examples of CAN Baud Rate Settings for Commonly Frequencies
Description
Segments
Registers
CAN
Rate
(Kbps)
fCLKIO
(MHz)
Sampling
Point
TQ
(µs)
Tbit
(TQ)
Tprs
(TQ)
Tph1
Tph2
Tsjw
(TQ)
(TQ)
(TQ)
CANBT1 CANBT2 CANBT3
69%(1)
0.0625
0.125
16
8
7
3
7
3
7
3
7
3
7
3
7
3
5
4
4
2
4
2
4
2
4
2
4
2
4
2
3
1
1
1
1
1
1
1
1
1
1
1
1
1
0x00
0x02
0x02
0x06
0x06
0x0E
0x08
0x12
0x0E
0x1E
0x12
0x26
0x00
0x0C
0x04
0x0C
0x04
0x0C
0x04
0x0C
0x04
0x0C
0x04
0x0C
0x04
0x08
0x36(2)
0x13
0x37
0x13
0x37
0x13
0x37
0x13
0x37
0x13
0x37
0x13
0x24(2)
1000
500
250
200
125
100
1000
500
250
200
125
100
75%
2
0.125
16
8
4
75%
75%
75%
75%
75%
67%(1)
75%
75%
75%
75%
75%
0.250
2
0.250
16
8
4
0.500
2
16.000
0.3125
0.625
16
8
4
2
0.500
16
8
4
1.000
2
0.625
16
8
4
1.250
2
0.083333
12
x
3
- - - n o d a t a - - -
0.166666
0.250
12
8
5
3
7
3
8
5
7
3
8
5
3
2
4
2
6
3
4
2
6
3
3
2
4
2
5
3
4
2
5
3
1
1
1
1
1
1
1
1
1
1
0x02
0x04
0x04
0x0A
0x04
0x08
0x0A
0x16
0x0A
0x12
0x08
0x04
0x0C
0x04
0x0E
0x08
0x0C
0x04
0x0E
0x08
0x25
0x13
0x37
0x13
0x4B
0x25
0x37
0x13
0x4B
0x25
0.250
16
8
0.500
12.000
0.250
20
12
16
8
0.416666
0.500
1.000
0.500
20
12
0.833333
Notes: 1. See Section 16.4.3 “Baud Rate” on page 148.
2. See Section • “Bit 0 – SMP: Sample Point(s)” on page 164
172
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