The [SEENGREAT] 라즈베리파이용 2채널 CAN 버스 확장 모듈 [220488] is a dual-channel CAN (Controller Area Network) bus expansion module designed specifically for Raspberry Pi. This module allows Raspberry Pi to communicate with CAN bus devices, making it ideal for automotive, industrial, and IoT applications. It supports high-speed communication and is compatible with a wide range of CAN-enabled devices.

• Automotive diagnostics and communication
• Industrial automation and control systems
• IoT applications requiring CAN bus communication
• Robotics and embedded systems
• Data logging and monitoring in CAN networks

• Channels: 2 independent CAN bus channels
• Communication Protocol: CAN 2.0A and CAN 2.0B
• Baud Rate: Up to 1 Mbps
• Power Supply: 5V (via Raspberry Pi GPIO header)
• Interface: SPI (Serial Peripheral Interface)
• Controller: MCP2515 CAN controller
• Transceiver: TJA1050 CAN transceiver
• Operating Temperature: -40°C to 85°C
• Dimensions: 65mm x 56mm

The module connects to the Raspberry Pi via the GPIO header. Below is the pin configuration:

1. Hardware Setup:

   • Mount the module onto the Raspberry Pi GPIO header.
   • Connect CAN_H and CAN_L lines of the CAN bus to the module's terminal block.
   • Ensure proper termination resistors (120Ω) are present at both ends of the CAN bus.

2. Software Setup:

   • Install the necessary libraries and drivers for the MCP2515 CAN controller.
   • Configure the SPI interface on the Raspberry Pi.

3. Basic Circuit Example:

   • Connect the module to a CAN bus network with other CAN-enabled devices.
   • Use the Raspberry Pi to send and receive CAN messages.

• Ensure the Raspberry Pi SPI interface is enabled via raspi-config.
• Use proper grounding to avoid noise and communication errors.
• Verify the baud rate and CAN ID settings match those of the other devices on the CAN bus.
• Avoid long cable runs to minimize signal degradation.

Below is an example Python script to initialize and send a CAN message using the module:

import can
import time

bus = can.interface.Bus(channel='can0', bustype='socketcan')

msg = can.Message(arbitration_id=0x123, data=[0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88], is_extended_id=False)

try: # Send the CAN message bus.send(msg) print("Message sent on CAN bus") except can.CanError: print("Failed to send message")

try: response = bus.recv(timeout=1.0) # Wait for 1 second if response: print(f"Received message: {response}") else: print("No response received") except Exception as e: print(f"Error receiving message: {e}")

• Install the python-can library using pip install python-can before running the script.
• Replace can0 with the correct CAN interface name (e.g., can1) if using the second channel.

1. No Communication on the CAN Bus:

   • Cause: Incorrect wiring or missing termination resistors.
   • Solution: Verify connections and ensure 120Ω resistors are present at both ends of the CAN bus.

2. SPI Interface Not Working:

   • Cause: SPI not enabled on the Raspberry Pi.
   • Solution: Enable SPI via raspi-config and reboot the Raspberry Pi.

3. CAN Messages Not Being Sent or Received:

   • Cause: Mismatched baud rate or CAN ID.
   • Solution: Ensure the baud rate and CAN ID match those of other devices on the network.

4. Module Overheating:

   • Cause: Excessive current draw or improper power supply.
   • Solution: Check the power supply and ensure the module is not overloaded.

• Use a CAN bus analyzer to monitor traffic and diagnose issues.
• Double-check the pin connections and ensure the module is securely mounted on the Raspberry Pi.
• Test the module with a simple loopback configuration to verify functionality.

By following this documentation, users can effectively integrate the [SEENGREAT] 라즈베리파이용 2채널 CAN 버스 확장 모듈 [220488] into their projects and leverage its capabilities for reliable CAN bus communication.