How to configure and use CAN bus

This page explains how to enable the CAN bus on ODROID-C1/C1+/C0 via HW SPI interface.
Detail instruction to exchange data with a MCP2515 Bus Monitor board is also documented.
can_bus

H/W connection

The following products are required to configure the hardware:

ODROID-C1+, C Tinkering Kit, MCP2515_CAN module

ODROID-C1+ C Tinkering Kit mcp2515

Reference circuit

circuit example

Connect CAN module and ODROID-C1 using tinkering kit

T-Board C1+CAN

  • Before S/W installing, you must to modify the mcp2515 driver to set the amlogic GPIO IRQ.
  • Please apply this patch to your kernel.
  • mcp251x patch
  • Unzip the zip file and use 'git apply odroid-c1-mcp251x.patch'
  • Edit arch/arm/boot/dts/meson8b_odroidc.dts can0 section uncomment.
  • This patch file was created in the odroidc-3.10.y branch.
  • After patching, the kernel version is Linux odroid 3.10.107

S/W installation

Enable the CAN controller kernel driver

ODROID-C1 platform with a MCP2515 chip the configuration is: Linux Kernel Configuration 

    Networking support
       CAN bus subsystem support
          CAN device drivers
              Platform CAN drivers with Netlink support
                CAN bit-timing calculation
                Microchip MCP251x SPI CAN controller

Reflash kernel and rootfs See below for how to build and install the kernel.
odroid-c1 build kernel

Verifying CAN support configuration

Load all the required drivers. (sudo password : odroid)
modprobe can_raw
modprobe spicc
modprobe mcp251x mcp251x_enable_dma=1
odroid@odroid:~$ sudo su
root@odroid:~# modprobe can_raw
root@odroid:~# modprobe spicc
root@odroid:~# modprobe mcp251x mcp251x_enable_dma=1
Verify the CAN host driver is registered correctly
root@odroid:~# ls /sys/class/net/
can0  eth0  ip6tnl0  lo  sit0
root@odroid:~# ifconfig can0
can0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          NOARP  MTU:16  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
 
root@odroid:~#
Power on CAN hardware

Set the bitrate before all operations Example: Set the bitrate of the can0 interface to 125kbps: 

ip link set can0 type can bitrate 125000 triple-sampling on
ifconfig can0 up
root@odroid:~# ip link set can0 type can bitrate 125000 triple-sampling on
root@odroid:~# ifconfig can0 up
root@odroid:~# ifconfig
can0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          UP RUNNING NOARP  MTU:16  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
 
eth0      Link encap:Ethernet  HWaddr 00:1e:06:10:18:1c  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:40 
 
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:1360 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1360 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:108256 (108.2 KB)  TX bytes:108256 (108.2 KB)
 
root@odroid:~#
Installing SocketCAN utils

can-utils package is a collection of CAN drivers and networking tools for Linux. It allows interfacing with CAN bus devices in a similar fashion as other network devices. 

sudo apt install can-utils
Loopback test on a single CAN port

loopback mode on can0 

ifconfig can0 down
ip link set can0 type can bitrate 125000 loopback on
ifconfig can0 up
ip -details link show can0
root@odroid:~# ifconfig can0 down
root@odroid:~# ip link set can0 type can bitrate 125000 loopback on
root@odroid:~# ifconfig can0 up
root@odroid:~# ip -details link show can0
5: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN mode DEFAULT group default qlen 10
    link/can  promiscuity 0 
    can <LOOPBACK,TRIPLE-SAMPLING> state ERROR-ACTIVE restart-ms 0 
          bitrate 125000 sample-point 0.875 
          tq 500 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1
          mcp251x: tseg1 3..16 tseg2 2..8 sjw 1..4 brp 1..64 brp-inc 1
          clock 10000000
root@odroid:~#

The following command shows the received message from the CAN bus 

candump can0

On second terminal, The following command sends 3 bytes on the bus (0x11, 0x22, 0x33) with the identifier 500. 

cansend can0 500#11.22.33

How to test CAN-bus link between 2 ODROID-C1 boards

Connect CANL, CANH pins of two ODROID-C1 boards
CAN-bus link Link example

Power-up both boards Type the following into the shell of both boards for configuration the CAN bus device: 

modprobe can_raw
modprobe spicc
modprobe mcp251x mcp251x_enable_dma=1
ip link set can0 type can bitrate 125000 triple-sampling on
ifconfig can0 up

Type the following to the shell of board 1 (which is used for testing receiving over can0 device): 

candump can0

Type the following to the shell of board 2 (which is used for testing sending data packets over can0 device): 

cansend can0 500#11.22.33

At this point, board 1 will receive the data packet sent from board 2: 

root@odroid:~# candump can0
  can0  500   [3]  11 22 33
  can0  500   [3]  11 22 33

For XU4 users

Useful thread for the XU4 board