Rock3/dev/can
ROCK 3 > Development > CAN bus communication
Description
This guide tells about how to use can on ROCK 3A.
Preparation
- Two ROCK 3A running Linux OS
- Two SN65HVD23x 3.3-V CAN Bus Transceivers boards.
- Several Dupont wires.
Operations on ROCK 3A
Install can test tool
$ sudo apt update $ sudo apt-get install can-utils iproute2
Check the information about can
Check can device
$ ifconfig can0
can0: flags=193<UP,RUNNING,NOARP> mtu 72
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 10 (UNSPEC)
RX packets 144 bytes 1152 (1.1 KiB)
RX errors 175 dropped 0 overruns 0 frame 35
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 62
See more details about device can0
$ ip -details -statistic link show can0
2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 72 qdisc pfifo_fast state UP mode DEFAULT group defa
ult qlen 10
link/can promiscuity 0 minmtu 0 maxmtu 0
can <FD> state ERROR-WARNING (berr-counter tx 0 rx 0) restart-ms 0
bitrate 1000000 sample-point 0.740
tq 20 prop-seg 18 phase-seg1 18 phase-seg2 13 sjw 1
rockchip_canfd: tseg1 1..128 tseg2 1..128 sjw 1..128 brp 1..256 brp-inc 2
dbitrate 1000000 dsample-point 0.720
dtq 40 dprop-seg 8 dphase-seg1 9 dphase-seg2 7 dsjw 1
rockchip_canfd: dtseg1 1..32 dtseg2 1..16 dsjw 1..16 dbrp 1..256 dbrp-inc 2
clock 100000000
re-started bus-errors arbit-lost error-warn error-pass bus-off
0 140 0 0 15 0 numtxqueues 1 n
umrxqueues 1 gso_max_size 65536 gso_max_segs 65535
RX: bytes packets errors dropped overrun mcast
1152 144 175 0 35 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0
Test can function by loopback test
Here we need one ROCK 3A.
$ sudo ip link set can0 down $ sudo ip link set can0 type can bitrate 1000000 dbitrate 1000000 loopback on fd on $ sudo ip link set can0 up $ sudo candump can0 & $ sudo cansend can0 123#11223344 can0 123 [4] 11 22 33 44
You can run more candump can0 & to get more answer.
Test can function between two ROCK 3A
Hardware connection
ROCK 3A One --- SN65HVD23x 3.3-V CAN Bus Transceivers Board One --- SN65HVD23x 3.3-V CAN Bus Transceivers Board Two --- ROCK 3A Two
Example: ROCK 3A Two send data to ROCK 3A One via can
This is the c program : Media:Can_test.zip
ROCK 3A One:
$ gcc -Wall -g -O0 -o can_receive can_receive.c $ sudo ./can_receive this is a can receive demo can_id = 0x123 can_dlc = 8 data[0] = 1 data[1] = 2 data[2] = 3 data[3] = 4 data[4] = 5 data[5] = 6 data[6] = 7 data[7] = 8
ROCK 3A Two:
$ gcc -Wall -g -O0 -o can_send can_secd.c $ sudo ./can_send this is a can send demo can_id = 0x123 can_dlc = 8 data[0] = 1 data[1] = 2 data[2] = 3 data[3] = 4 data[4] = 5 data[5] = 6 data[6] = 7 data[7] = 8
These are the communication between the two boards.
Troubleshooting
Check ROCK 3 FAQs first, if it doesn't help, start a new post on the forum https://forum.radxa.com/c/rock3.