CAN Bus Configuration

CAN Bus

The BOAT IO and NMEA-4 CAN buses both uses the Microchip MCP2515. This is natively supported by the Raspberry Pi overlay, but has to be configured. Follow the steps below.

Step 1 - Install Updates

pi@raspberrypi ~ $ sudo apt-get update
pi@raspberrypi ~ $ sudo apt-get upgrade
pi@raspberrypi ~ $ sudo reboot

Step 2 - Enable a CAN device tree

pi@raspberrypi ~ $sudo nano /boot/config.txt

Edit the pi configuration and add an overlay for the device

dtparam=spi=on

dtoverlay=mcp2515-can0,oscillator=8000000,interrupt=25

dtoverlay=spi0-bcm2835-overlay

Reboot

Step 3 - Download the CAN bus test software

Download the test software from http://www.skpang.co.uk/dl/can-test_pi2.zip

Extract the files to a folder

There are various programs in the folder, but the two most useful are candump and cansend

To make them executable use the commands

pi@raspberrypi ~ $ chmod u+x cansend
pi@raspberrypi ~ $ chmod u+x candump

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Step 4 - Configure the CAN Bus

pi@raspberrypi ~ $ sudo /sbin/ip link set can0 up type can bitrate 500000

This sets up the CAN bus for 500k bps. Change this number to match your bus speed

Now monitor traffic on the bus using the command

pi@raspberrypi ~ $ ./candump can0

To send data issue the command

pi@raspberrypi ~ $ ./cansend can0 000007DF#0201050000000000

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Step 5 - Programming with Python

Download the Python-CAN files from:

https://bitbucket.org/hardbyte/python-can/get/4085cffd2519.zip

Unzip and install by entering:

pi@raspberrypi ~ $ sudo python3 setup.py install 

Bring the CAN interface up if it is not already done:

pi@raspberrypi ~ $ sudo /sbin/ip link set can0 up type can bitrate 500000

Now start python3:

python3

To sent a message out type the following lines:

import can

bus = can.interface.Bus(channel='can0', bustype='socketcan_native')msg= can.Message(arbitration_id=0x7de, data=[0, 25, 0, 1, 3, 1, 4, 1], extended_id=False)

bus.send(msg)