CANnuccia

A bootloader for in-field programming of MCUs via CAN bus.
See CANale for a tool to upload firmware to CANnuccia devices.

Supported hardware

• STM32 microcontrollers with CAN via bxCAN.
  Tested on the generic STM32F103C8T6 (ARM Cortex-M3) "blue pill" boards.
• AVR microcontrollers with CAN via MCP25x CAN controllers.
  Tested on ATMega328p paired with MCP25625.

Usage

Devices on a CANnuccia network have an 8-bit identifier (stored in the Data0 option byte on STM32 and on byte 0 of EEPROM on AVR). CANnuccia starts on chip reset, reads this id, and sets CAN filters accordingly to listen for commands for the target device; see docs/CANnuccia.xlsx for more information on the protocol.
If no CANnuccia command is received within a timeout (or when a "programming done" command is received), CANnuccia terminates and jumps to the user program.

Prerequisites

• CMake 3.14+

• For STM32: GNU compiler toolchain for ARM (arm-none-eabi) and a standard-compliant <stdint.h> header (available for instance from newlib)

• For AVR: GNU compiler toolchain for AVR and the avr-libc standard library

Compiling

Create a build directory and generate build files via CMake, then compile the project.

You have to use one of the provided toolchain files (-DCMAKE_TOOLCHAIN_FILE=):

• For STM32: src/stm32/STM32Toolchain.cmake
• For AVR: src/avr/AVRToolchain.cmake

Each toolchain file exposes target-specific configuration options to CMake.

Goals

• Simplicity and small footprint
  • Written in C99
  • Relies on a minimal amount of dependencies (basically just <stdint.h> on STM32)
  • Simple but reliable protocol over CAN bus
• Thin abstraction over target hardware, designed for a minimal amount of work when porting to different platforms
• Complete isolation between the bootloader and the uploaded programs (and no RAM usage after the bootloader terminates)

License

Mozilla Public License, Version 2.