ExpertCommunications and Networking
CAN Bus Bench Network
Build two standalone CAN nodes and exchange short messages over a correctly terminated bench bus.
Parts from the database
- MCP2515 ร 2CAN controllers on modules
- MCP2551-I/P ร 2CAN physical-layer transceivers
- ATmega328P-PU ร 2Use two 5 V Arduino-compatible development boards
Other supplies
- two 5 V Arduino-compatible boardsCommon build supply
- two MCP2515+transceiver modules (verify onboard transceiver part)Common build supply
- 120 ฮฉ termination resistors at the two bus endsCommon build supply
- short twisted-pair wireCommon build supply
- USB cablesCommon build supply
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Connections
- Connect each controller module to its MCU using SPI and its required CS/INT pins; follow the module's pin labels.
- Connect CANH-to-CANH and CANL-to-CANL with a twisted pair; fit one 120 ฮฉ terminator at each physical end only.
- Share ground between nodes for this short bench test. Verify each module already has or lacks a termination resistor before adding one.
- The MCP2551 is a 5 V transceiver; use a 5 V logic host/module and confirm the actual module design before mixing logic levels.
Build steps
- Install a maintained MCP_CAN library and confirm both modules initialize at the same bitrate.
- Run a receive sketch on one node and a periodic transmit sketch on the other.
- Send a small fixed CAN identifier and payload, then verify the receiver prints exact bytes.
- Disconnect one terminator as a deliberate diagnostic and observe errors; restore termination before normal use.
Software and firmware setup
Firmware is required on both nodes, but transmit/receive sketches are not included yet. Use the MCP_CAN library's send and receive examples, configured for your module's oscillator frequency and the same bitrate. This guide's bench wiring is not for connection to a vehicle network.
Test your build
The receiving node should report frames without persistent error counters on a short, correctly terminated bench bus. This is a lab network, not a connection to a vehicle.
Troubleshooting
- No frames: check bitrate, oscillator frequency configured in the library, CS pin and transceiver wiring.
- Intermittent errors: verify CANH/CANL polarity, termination count and the module's onboard resistor jumpers.
- If boards heat or reset, disconnect immediately and recheck 5 V power and bus wiring.
Safety and limitations
Keep the network isolated from vehicle wiring. Never attach an experimental node to a car's CAN bus; a faulty frame can disrupt vehicle systems.
Manufacturer and platform documentation
Community Notes for This Project
These are unverified visitor contributions, separate from the build guide and manufacturer specifications. Verify technical advice against the linked datasheets before relying on it.
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