PicoCAN

PicoCAN

PicoCAN is a custom devboard based on the RP2040 that features a built-in CAN controller and transceiver (the MCP25625 to be exact).

Key Features

• USB-C connection for easy programming
• RP2040 based, with the same size as the Pi Pico
• CAN BUS using MCP25625
  • Built-in 120Ω termination resistor, which can be enabled by bridging the two pins near the CANL pin
  • To use interrupt mode instead of polling for incoming messages, the INT pin can be bridged to the neighboring GPIO21 pin. (See 2nd image above)
• Support for powering with 5V through VSYS pin
• 28 usable GPIO pins, including 4 ADC pins
• Two on-board LEDs (Green and Red)
  • The red LED also shares pin 24 on the board's 2.54mm headers
  • The green LED is not connected to any of the PicoCAN's external pins
    • Internally connected to the RP2040's GPIO25.

Using the CAN bus

To interface with the CAN bus, you can use any library that supports the MCP25625. There are a few examples that use the MCP_CAN library in the ./firmware_examples folder; they are adapted from https://github.com/coryjfowler/MCP_CAN_lib.

More Efficient Than Polling

As shown in the 2nd photo above, the INT pin can be bridged to GPIO21. Pin 21 can be configured as an pullup input, and it will inform the RP2040 when there is a pending CAN bus message to be read.

Building the PicoCAN

The PicoCAN can be ordered from sites like JLCPCB (and optionally assembled too). The KiCAD source files are in ./KiCAD and the production gerber files are in ./KiCAD/prod along with the bom.

This is what JLC PCBA gets you! These don't have the headers soldered on yet. SEE BUILD.md FOR STEPS TAKEN

Images

Schematic

BOM

Exhaustive PCB component BOM available at ./KiCAD/prod/PicoCAN.csv.