MCP2515

#![no_std] library for interacting with MCP2515 CAN controller chips. Platform-agnostic, tested with arduino-hal on ATmega2560.

Inspired by the following C++ libraries:

• MCP_CAN_lib
• arduino-MCP2515

Cargo Features

All features are disabled by default.

• defmt - Implements defmt::Format for most public types so they can be printed using defmt::info!() and relatives
• ufmt - Implements ufmt::uDebug for most public types so they can be printed using ufmt::uwriteln!() and relatives

Examples

Examples for some common microcontrollers are available in the examples/ folder.

• Arduino Uno
  • Easily adapted to other AVR-based boards
• Raspberry Pi Pico
  • Easily adapted to other RP2040-based boards

Usage

Import the relevant HAL crate for your platform. For this example I'm using arduino-hal on an ATmega2560.

#![no_std]
#![no_main]

use panic_halt as _;

use arduino_hal::{spi::Settings, Delay, Spi};
use embedded_can::{ExtendedId, Frame, Id};
use embedded_hal_bus::spi::ExclusiveDevice;
use mcp2515::{error::Error, frame::CanFrame, regs::OpMode, CanSpeed, McpSpeed, MCP2515};

#[arduino_hal::entry]
fn main() -> ! {
    let dp = arduino_hal::Peripherals::take().unwrap();
    let pins = arduino_hal::pins!(dp);

    let mut delay = Delay::new();
    let mut serial = arduino_hal::default_serial!(dp, pins, 115200);

    ufmt::uwriteln!(&mut serial, "Hello, world!").unwrap();

    let (spi, cs) = Spi::new(
        dp.SPI,
        pins.d13.into_output(),
        pins.d11.into_output(),
        pins.d12.into_pull_up_input(),
        pins.d10.into_output(),
        Settings {
            data_order: arduino_hal::spi::DataOrder::MostSignificantFirst,
            clock: arduino_hal::spi::SerialClockRate::OscfOver128,
            mode: embedded_hal::spi::MODE_0,
        },
    );
    let spi_device = ExclusiveDevice::new(spi, cs, Delay::new()).unwrap();
    let mut can = MCP2515::new(spi_device);
    can.init(
        &mut delay,
        mcp2515::Settings {
            mode: OpMode::Loopback,       // Loopback for testing and example
            can_speed: CanSpeed::Kbps100, // Many options supported.
            mcp_speed: McpSpeed::MHz8,    // Currently 16MHz and 8MHz chips are supported.
            clkout_en: false,
        },
    )
    .unwrap();

    loop {
        // Send a message
        let frame = CanFrame::new(
            Id::Extended(ExtendedId::MAX),
            &[0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08],
        )
        .unwrap();
        can.send_message(frame).unwrap();
        ufmt::uwriteln!(&mut serial, "Sent message!").unwrap();

        // Read the message back (we are in loopback mode)
        match can.read_message() {
            Ok(frame) => ufmt::uwriteln!(&mut serial, "Received frame {:?}", frame).unwrap(),
            Err(Error::NoMessage) => ufmt::uwriteln!(&mut serial, "No message to read!").unwrap(),
            Err(_) => panic!("Oh no!"),
        }

        arduino_hal::delay_ms(1000);
    }
}

Output over serial:

Sent message!
No message to read!
Sent message!
Received frame CanFrame { id: Extended(ExtendedId(536870911)), rtr: false, dlc: 8, data: [1, 2, 3, 4, 5, 6, 7, 8] }
Sent message!
Received frame CanFrame { id: Extended(ExtendedId(536870911)), rtr: false, dlc: 8, data: [1, 2, 3, 4, 5, 6, 7, 8] }
Sent message!
Received frame CanFrame { id: Extended(ExtendedId(536870911)), rtr: false, dlc: 8, data: [1, 2, 3, 4, 5, 6, 7, 8] }

License

Licensed under either of

• Apache License, Version 2.0 ([LICENSE-APACHE] or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license ([LICENSE-MIT] or http://opensource.org/licenses/MIT)

at your option.