(
)
(
)
0.1
2
13
1
0.1
s
x
x
s
s
m
m
m
-
(
)
(
)
(
)
(
)
min
1,
2
2
13
_
2
TSeg TSeg
x
x bit
time
TSeg
-
(
)
(
)
0.1
2
13
1
0.1
s
x
x
s
s
m
m
m
-
(
)
(
)
(
)
(
)
min
1,
2
2
13
_
2
TSeg TSeg
x
x bit
time
TSeg
-
Functional Description
t
q
100 ns
=
t
CAN_CLK
delay of bus driver
60 ns
=
delay of receiver circuit
40 ns
=
delay of bus line (40 m)
220 ns
=
t
Prop
700 ns
=
INT (2* 1) = 7 • t
q
t
SJW
100 ns
=
1 • t
q
t
TSeg1
800 ns
=
t
Prop
+ t
SJW
t
TSeg2
100 ns
=
Information Processing Time + 1 • t
q
t
Sync-Seg
100 ns
=
1 • t
q
bit time
1000 ns
=
t
Sync-Seg
+ t
TSeg1
+ t
TSeg2
tolerance for CAN_CLK
0.43 %
=
=
In this example, the concatenated bit time parameters are (1-1)
3
&(8-1)
4
&(1-1)
2
&(1-1)
6
, so the bit timing
register is programmed to = 00000700.
23.3.16.2.3 Example for Bit Timing at Low Baud Rate
In this example, the frequency of CAN_CLK is 2 MHz, BRP is 1, the bit rate is 100 KBit/s.
t
q
1 µs
=
t
CAN_CLK
Delay of bus driver
200 ns
=
Delay of receiver circuit
80 ns
=
Delay of bus line (40 m)
220 ns
=
t
Prop
1 µs
=
1 • t
q
t
SJW
4 µs
=
4 • t
q
t
TSeg1
5 µs
=
t
Prop
+ t
SJW
t
TSeg2
3 µs
=
Information Processing Time + 3 • t
q
t
Sync-Seg
1 µs
=
1 • t
q
Bit time
9 µs
=
t
Sync-Seg
+ t
TSeg1
+ t
TSeg2
Tolerance for CAN_CLK
=
=
In this example, the concatenated bit time parameters are (3-1)
3
&(5-1)
4
&(4-1)
2
&(2-1)
6
, so the bit timing
register is programmed to = 0x000024C1.
3914
Controller Area Network (CAN)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated