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.
H/W connection
The following products are required to configure the hardware:
ODROID-C1+, C Tinkering Kit, MCP2515_CAN module
Reference circuit
Connect CAN module and ODROID-C1 using tinkering kit
- Before S/W installing, you must to modify the mcp2515 driver to set the amlogic GPIO IRQ.
- Please apply this patch to your kernel.
- 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
- target
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
- target
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
- target
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
- target
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
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:
- target
root@odroid:~# candump can0 can0 500 [3] 11 22 33 can0 500 [3] 11 22 33
odroid