Goals

• Generic implementation using STM32 HAL API to compile onto every STM32 board.
• For the most used boards, optimize code paths using direct register access.
• Make adding boards easy
• Make as compatible with default libraries as possible

Project structure

Director	Description
system/CMSIS	CMSIS header files from ARM for cortex-M0/M3/M4/M7 microcontrollers
system/STM32XX/CMSIS_Inc	CMSIS header files specific STM32 chips, contains memory layout and register access for every chip
system/STM32XX/CMSIS_Src	CMSIS startup assembly files specific STM32 chips, contains ISR vector for interrupt handlers and reset handler default implementation
system/STM32XX/HAL_Inc	STM32 Hardware Abstraction Layer headers for every chip series
system/STM32XX/HAL_Src	STM32 Hardware Abstraction Layer implementation for every chip series
system/STM32XX/stm32_chip	For every chip, default and alternate pins, clock frequencies, cannels for peripherals: SPI, I2C, ADC... autogenerated from CubeMX db/*.xml files with tools/script/generate_build_define.py.
cores/arduino/	Arduino API definitions and Arduino-utility functions.
cores/arduino/stm32_HAL	Select (compile) the specific files from system/STM32XX/HAL_Src, based on boards.txt *.build.series value
cores/arduino/usb	STM32 USB Middleware
cores/arduino/stm32	STM32 implementation of the Arduino API. First implementation is a light wrapper around HAL
libraries/[SPI|Wire|...]	STM32 implementation of the Arduino libraries API. First implementation is a light wrapper around HAL
variants/.../*	Variant specific files: ldscript.ld for memory layout, systemclock_config.c for clock setup, generated by STM32CubeMX, variant.* for variant pin layout and pin definitions (pin layout can be copy/pasted from system/STM32XX/stm32_chip/*).

General development direction

• Self-test code to run on a board to check if the API works for that variant.
• Automatic unit test compilation. This ensures that a code change does not break other boards.
• Automatic library compilation, to be as arduino-compatible as possible.
• Benchmarks to pinpoint bottlenecks.
• Hacker-friendly: Enable to use HAL/CMSIS; enable overriding of every IRQ handler.
• Add DFU/MSC/HID/MIDI to USB. Rewrite USB to PluggableUSB to be more arduino-compatible.
• Create SDIO library
• Create I2S library
• Create CAN library