CAN Bus Testing Project

A PlatformIO project for testing CAN bus communication between microcontrollers using MCP2515 CAN controllers.

Hardware

• Arduino Uno R4 WiFi (Receiver with LED Matrix)
• Arduino Nano ESP32 (Alternative platform)
• MCP2515 CAN Controller modules
• LED Matrix (for message display on Uno R4 WiFi)

Project Structure

├── CANReceive/          # Generic CAN receiver
├── CANReceiveUno/       # Arduino Uno R4 WiFi CAN receiver with LED matrix
├── CANTransmit/         # CAN transmitter
├── main.py             # Python script for monitoring CAN bus via serial
└── platformio.ini      # PlatformIO configuration

Features

CAN Receiver (Uno R4 WiFi)

• Receives CAN messages split across two frames (ID: 0x123, 0x124)
• Assembles 16-character messages from 8-byte frames
• Displays message reception status on LED matrix
• Serial debugging output
• Timeout protection for incomplete messages
• Memory-safe buffer handling

CAN Transmitter

• Sends 16-character messages split into two 8-byte CAN frames
• Generates messages with format: "ALEX " + 8 random letters + " " + sequence number
• Configurable transmission interval

Python Monitor

• Monitors CAN bus traffic via Waveshare USB-CAN adapter
• Parses and displays CAN frames in real-time
• Supports variable-length frame format

Getting Started

1. Hardware Setup

   • Connect MCP2515 modules to your microcontrollers
   • Wire CS pin to GPIO 5
   • Connect CAN_H and CAN_L between modules
   • Add 120Ω termination resistors at both ends

2. Software Setup

   # Install PlatformIO
   pip install platformio
   
   # Build for Arduino Uno R4 WiFi
   pio run -e uno_r4_wifi
   
   # Build for Arduino Nano ESP32
   pio run -e arduino_nano_esp32
   
   # Upload to device
   pio run -e uno_r4_wifi -t upload

3. Python Monitoring

   # Update PORT in main.py to match your USB-CAN adapter
   python main.py

Configuration

CAN Settings

• Bitrate: 500 KBPS
• Crystal: 8 MHz
• Frame IDs: 0x123 (first frame), 0x124 (second frame)

Message Format

• Total Length: 16 characters
• Frame 1 (0x123): Bytes 0-7
• Frame 2 (0x124): Bytes 8-15
• Timeout: 1 second for complete message assembly

Dependencies

• autowp/autowp-mcp2515@^1.2.1 - MCP2515 CAN controller library
• Arduino_LED_Matrix - LED matrix support (Uno R4 WiFi)
• pyserial - Python serial communication (for monitoring)

Troubleshooting

1. No CAN communication

   • Check wiring connections
   • Verify termination resistors (120Ω)
   • Ensure matching bitrates and crystal frequencies

2. Incomplete messages

   • Check for electrical noise
   • Verify frame timing
   • Monitor timeout messages in serial output

3. LED Matrix not working

   • Ensure using Arduino Uno R4 WiFi
   • Check LED_Matrix library installation

License

MIT License - Feel free to use and modify for your projects.