RPi-CAN Card Installation Guide 

Table of contents
  1. RPi-CAN Card Installation Guide
    1. Overview
    2. What’s Needed
    3. Connection Diagram
    4. Connector Assignments
    5. Installation Steps
    6. Configuring the MCP2515 on RPi
    7. Auto-Starting the CAN Interface on RPi
    8. Testing & Troubleshooting Tips
    9. References

Overview

This section outlines the steps to set up a the RPi-CAN Card with an Raspberry Pi (RPi) for integration with the LCC Fusion Node Cluster. The RPi-CAN provides all of the connections between an RPi, MCP2515 module (transceiver for CAN communications), and a Node Bus Hub. No external wiring is required.

What’s Needed

Component Purpose
RPi-CAN Card (assembled with Pi & MCP2515) Interfaces between the Pi, MCP2515 module, Node Bus, and CAN Bus
RPI Software (OS and JMRI) Runs JMRI for CAN communications. Use Steve Todd’s preconfigured JMRI image
HDMI monitor & USB keyboard/mouse Provides a local console for initial RPi configuration and troubleshooting
microSD card (8 GB or larger) Holds the preconfigured JMRI OS image
microSD card reader & imager Needed to flash the JMRI image onto your card (e.g. with balenaEtcher)
Node Card & Power Supply Interfaces with CAN network and cards (via Node Bus Hub)
Network Cable (CAT5/CAT6) Connects the Pi (via RPi-CAN Card) to the Node Card and cards to breakout boards

Connection Diagram 

flowchart LR
  subgraph layout ["Train Layout"]
  	direction LR
  	subgraph hub["Node Bus Hub"]
      direction LR
      nodeCard[["Node Card"]]
      subgraph rpiCanCard["RPI-CAN Card"]
        rpi["RPI Module"]
        transceiver["MCP2515 Module<br>(CAN Transceiver)"]
      end
      ioCards[["I/O cards"]]
    end
    mkm["Monitor, <br>Keyboard,<br>Mouse"]
    jmri["JMRI Software<br>CDI Config Tool"]
    pwrSupply(("Power Supply"))
    breakout1["breakout boards"]
    devices1(("devices"))
  end
  mkm -.-> |"HDMI, USB"|rpi
  jmri -.- |"runs on"|rpi
  pwrSupply -.-> |"1+ A @ 40 VDC max via<br>2-wire"| nodeCard
  nodeCard <--> |"Pwr/Comm via<br>Node Bus"|ioCards
  nodeCard <--> |"Pwr/Comm via<br>Node Bus"|rpiCanCard
  ioCards <--> |"I/O via<br>Network Cable"|breakout1
  breakout1 <-.-> |"I/O via<br>2-wire"|devices1

  classDef lightBlueStyle fill:lightblue,stroke:#2c7a2c,stroke-width:2px,font-size:16px;
  classDef lightGreenStyle fill:lightgreen,stroke:#333,stroke-width:2px,font-size:20px;
  class hub lightBlueStyle
  class rpiCanCard lightGreenStyle

Connector Assignments

Label Pins Function
J1 2-pin Power connection to MCP2515 Module
J2 8-pin Connects RPI with MCP2515 Module (power, CAN communications)
J3 4-pin Connects RPI with RPI-CAN Card (power, CAN communications)

Installation Steps

  1. Remove the MCP2515 module
    • Power off the system and disconnect the RPi-CAN Card from the Node Bus Hub.
    • Unscrew the two mounting screws securing the MCP2515 breakout board to the RPi-CAN Card.
    • Carefully lift the MCP2515 module straight up to disengage the header pins.
  2. Set the CAN termination jumper
    • On the underside of the MCP2515 board, locate the pads or pins labeled “TERM” or “120 Ω” between CAN_H and CAN_L.
    • Place the provided 120 Ω jumper cap across those pads to enable termination.
    • If this node sits in the middle of your CAN network, leave the jumper off instead.
  3. Reinstall the MCP2515 module
    • Align the module’s header pins with the socket on the RPi-CAN Card.
    • Gently press down until fully seated.
    • Re-fasten the two mounting screws—do not overtighten.
  4. Insert the microSD card
    • Flash the preconfigured JMRI image onto your microSD (8 GB+).
    • Insert the card into the Pi’s microSD slot on the RPi-CAN Card.
  5. Attach local console
    • Connect an HDMI monitor to the Pi’s HDMI port.
    • Plug in a USB keyboard (and mouse, if desired) to one of the Pi’s USB ports.
    • This provides direct access to the RPi console for any configuration prompts.
  6. Reconnect and power up
    • Plug the assembled RPi-CAN Card back into the Node Bus Hub.
    • Power on and verify that the Pi boots and comes up on the CAN bus (e.g. ifconfig can0 or via JMRI).

Configuring the MCP2515 on RPi

  1. 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.

  2. Add the following line at the end of the file (adjust the oscillator= value if your module’s crystal differs):

     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.

Auto-Starting the CAN Interface on RPi

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

  1. Open your network interfaces file:

    sudo nano /etc/network/interfaces/

  2. Add these lines at the end:

     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.

​ Note: The LCC Fusion Project’s firmware is built using the board’s CPU Frequency set to 240 MHz to align with the CAN bus speed of 125 kbps.

  1. Save and exit, then reboot:
sudo reboot

  1. Check the kernel has the MCP2515 driver loaded:

    lsmod | grep mcp251x

  2. Confirm the new can0 interface exists:

     ip link show can0

Testing & Troubleshooting Tips

1. Verify the CAN interface:

ifconfig can0

​ You should see can0 listed with flags including UP and non-zero RX/TX packet counters. Example Output:CAN Bus Status

2. Common Issues & Resolutions

  • can0 not found

    • Confirm dtoverlay=mcp2515-can0,oscillator=8000000,interrupt=25 is in /boot/config.txt.

    • Ensure these lines exist in /etc/modules:

    spi-dev
    mcp251x

  • Reboot: sudo reboot.

  • Interface is down or errors on bring-up

    • Bring it up manually:

      sudo ip link set can0 up type can bitrate 125000

    • Check kernel messages for clues:

      dmesg | grep -i mcp251x
dmesg | grep -i spi

  • No traffic or garbled frames

    • Verify termination resistors: 120 Ω jumpers must be fitted at both ends of your CAN bus.

    • Inspect wiring and connectors for loose pins or mis-routing.

    • Use candump to sniff traffic:

      sudo apt install can-utils
candump can0
  1. Next Steps

​ Once can0 is up and passing valid frames, move on to your JMRI or CDI configuration to map LCC Event IDs and throttle panels.

References

  1. 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.
  2. JMRI RaspberryPi as Access Point by Steve Todd provides details on the RPi image pre-configured for use with JMRI
Last updated on: December 17, 2025 © 2025 Pat Fleming