RPI-CAN Card Configuration Guide

Table of contents

RPI-CAN Card Configuration Guide

Introduction

This section outlines the steps to set up a Raspberry Pi (RPI) for CAN bus support using the MCP2515 module.

Step 1: Configuring the MCP2515 on RPI

First, configure the MCP2515 for communication in the RPI’s Linux environment:

sudo nano /boot/config.txt

This command opens the config.txt file using the nano editor. Add the following line at the end of the file:

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

Ensure the oscillator value corresponds to the one on your MCP2515 module (indicated on the silver oscillator).
Use interrupt value 25, as the card is designed to utilize RPI pin 25 for the (SPI) interrupt.

Note: When compiling the ESP32 firmware, ensure the board’s CPU Frequency is set to 240 MHz to align with the CAN bus speed.

Step 2: Auto-Starting the CAN Interface on RPI

Configure the RPI to bring up the CAN interface automatically upon boot:

sudo nano /etc/network/interfaces

Open the network interfaces file and add the following configurations:

auto can0
iface can0 inet manual
  pre-up /sbin/ip link set can0 type can bitrate 125000 triple-sampling on restart-ms 100
  up /sbin/ifconfig can0 up
  down /sbin/ifconfig can0 down

These settings initiate can0 as the interface with a bitrate of 125k.

Step 3: Testing the Configuration

To test the setup:

ifconfig can0

Run this command in a terminal window to confirm the CAN interface is correctly set up. Look for CAN Bus traffic.
Here an example of the ifconfig output, showing active CAN communications on CAN0 with data transmission.
- If encountering errors, check all connections, reboot both RPI and ESP32, and retest.
- Persistent issues may require rechecking configuration files, settings, and connections to the MCP2515 module.

References

Adding CAN to the Raspberry PI - provides information on selection of the MCP2515 board and information used in the design of RPI-CAN Card and Linux configuration.