cynovan / can

Connect to a CAN bus in Go

can

can provides an interface to a CAN bus to read and write frames. The library is based on the SocketCAN network stack on Linux.

Hardware

I'm using a Raspberry Pi 2 Model B and PiCAN2 CAN-Bus board for Raspberry Pi 2 to connect to a CAN bus.

Software

The Raspberry Pi runs Raspbian.

Configuration

Update /boot/config.txt with

dtparam=spi=on 
dtoverlay=mcp2515-can0-overlay,oscillator=16000000,interrupt=25 
dtoverlay=spi-bcm2835-overlay

and reboot.

After phyiscally connecting to the CAN bus, you have to set up the can network interface for a specific bitrate, i.e. 50 kB

sudo ip link set can0 up type can bitrate 50000

Running ifconfig should now include the can0 interface.

Test your configuration

You should test if you actually receive data from the CAN bus. You can either use the candump tool from the can-utils or a simple reimplementation under cmd/candump.go.

Either way you will see something like this

> go run $GOSRC/github.com/brutella/can/cmd/candump.go -if can0

can0 100  [6] 20 83 0C 00 67 29        ' ...g)'
can0 701  [1] 05                       '.'

Usage

Setup the CAN bus

bus, _ := can.NewBusForInterfaceWithName("can0")
bus.ConnectAndPublish()

Send a CAN frame

frm := can.Frame{
	ID:     0x701,
	Length: 1,
	Flags:  0,
	Res0:   0,
	Res1:   0,
	Data:   [8]uint8{0x05},
}

bus.Publish(frm)

Receive a CAN frame

bus.SubscribeFunc(handleCANFrame)

func handleCANFrame(frm can.Frame) {    
    ...
}

There is more to learn from the documentation.

Contact

Matthias Hochgatterer

Github: https://github.com/brutella

Twitter: https://twitter.com/brutella

License

can is available under the MIT license. See the LICENSE file for more info.