README.md

Doggie Pico

Description

This implementation provides a CAN Bus to USB adapter using the RP2040 microcontroller (commonly known as Raspberry Pico or Raspberry Pico W). It supports two configurations for interacting with a CAN Bus network, enabling communication via USB or UART. The adapter uses the slcan protocol (CAN over Serial), making it compatible with popular software tools such as SocketCAN, Python-can, and other slcan-compatible applications.

---

Supported Configurations

The Raspberry Pico implementation supports the following configurations:

1. USB and MCP2515 (SPI to CAN)

   • The USB port of the Pico is used for communication with the host system.
   • The MCP2515 (SPI to CAN) module is used for CAN Bus communication.
   • This configuration allows the device to interface with a CAN network while communicating with the host via USB.

   Connections:

   Function	Pico	MCP2515
   Vcc	VBUS	5v
   GND	GND	GND
   MOSI	GP19	SI
   MISO	GP16	SO
   Clock	GP18	SCK
   CS	GP17	CS

   

2. UART and MCP2515 (SPI to CAN)

   • The UART port of the Pico is used to communicate with the host system.
   • The MCP2515 (SPI to CAN) module is used for CAN Bus communication.
   • This configuration is useful when the USB port is unavailable or when using a serial connection instead of USB.

   Connections:

   Function	Pico	MCP2515	USB-UART
   Vcc	VBUS	5v	5v
   GND	GND	GND	GND
   MOSI	GP19	SI	-
   MISO	GP16	SO	-
   Clock	GP18	SCK	-
   CS	GP17	CS	-
   TX	GP0	-	RX
   RX	GP1	-	TX

   

---

How to Flash a Release

• USB and MCP2515:

  1. Download the release doggie_pico_usb_mcp.uf2.
  2. Connect the Pico in bootloader mode and copy the release.

• UART and MCP2515:

  1. Download the release doggie_pico_uart_mcp.uf2.
  2. Connect the Pico in bootloader mode and copy the release.

How to Compile and Flash

Prerequisites

probe-rs (para programar con otra pico): curl --proto '=https' --tlsv1.2 -LsSf https://github.com/probe-rs/probe-rs/releases/latest/download/probe-rs-tools-installer.sh | sh

1. Install Rust and cargo with support for ARM architecture.
   Follow the installation instructions from the official Rust website.

2. Add the target architecture:

   rustup target add thumbv6m-none-eabi
   

3. To program a Pico, you can put it in bootloader mode and copy the firmware or use another Pico as a probe.

• If you want to program your Pico by copying the firmware, install elf2uf2-rs:

  cargo install elf2uf2-rs
  

• If you want to program your Pico using another Pico as a probe, install probe-rs:

  curl --proto '=https' --tlsv1.2 -LsSf https://github.com/probe-rs/probe-rs/releases/latest/download/probe-rs-tools-installer.sh | sh
  

  Additionally, you have to modify doggie_pico/.cargo/config.toml:

  [target.'cfg(all(target_arch = "arm", target_os = "none"))']
  # runner = "elf2uf2-rs -d"
  runner = "probe-rs run --chip RP2040"
  
  [build]
  target = "thumbv6m-none-eabi"        # Cortex-M0 and Cortex-M0+
  
  [env]
  DEFMT_LOG = "trace"
  

  And setup a Pico as a probe by cloning the RPI debug probe repo, building it for the pico:

  git clone https://github.com/raspberrypi/debugprobe.git
  cd debugprobe
  mkdir build
  cd build
  cmake -DDEBUG_ON_PICO=ON ..
  make
  

  Copying the resulting .uf2 image to the Pico, and connecting it to the target Pico.

  Connections:

  Function	Pico Probe	Target Probe
  Vcc	VBUS	VBUS
  GND	GND	GND
  SWCLK	GP2	SWCLK
  SWDIO	GP3	SWDIO
  UART ->	GP4	GP1
  UART <-	GP5	GP0

  

  Note that you will be using the probe as a SWD programer and as a UART bridge, so you must compile doggie using the uart feature.

Compile and Flash the Firmware:

1. Connect the target Pico to the PC in bootloader mode or to the probe as shown before.

2. Build and flash with selected features

   • USB and MCP2515:

     cargo run --bin doggie_pico_usb_mcp --release
     

   • UART and MCP2515 (Use this feature if you are using the probe):

     cargo run --bin doggie_pico_uart_mcp --release