PIO + STM32H7 STM32Cube FreeRTOS demo

Description

Shows how a auto-generated STM32CubeMX project can be converted to be compiled with PlatformIO

STM32CubeMX configuration

1. Selected the board NUCLEO-H723ZG, initialize all peripherals in default mode
2. Activate Middleware -> FreeRTOS -> CMSIS_V2
3. Change SYS -> Timebase Source to "TIM2" (recommended since FreeRTOS uses SysTick)
4. Generate code for STM32CubeIDE, folder structure "advanced"

PlatformIO conversion

1. Create blank PlatformIO project for NUCLEO-H723ZG
2. Copy Core\Inc\* from STM32Cube project to include\*
3. Copy Core\Src\* from STM32Cube project to src\*
4. Copy Middlewares\Third_Party\FreeRTOS folder into lib
5. Copy STM32H723ZGTX_FLASH.ld to the root of the PIO project
6. Adapt platformio.ini to the following

[env:nucleo_h723zg]
platform = ststm32
board = nucleo_h723zg
framework = stm32cube
; select linker file generated by CubeMX
board_build.ldscript = STM32H723ZGTX_FLASH.ld
; make build system use our HAL config file
board_build.stm32cube.custom_config_header = yes
; force inclusion of lib/FreeRTOS
lib_deps = FreeRTOS
; needed compiler flags to 
; correctly build the port assembly files
; and add freertos subfolders to include path
build_flags =
  -mfpu=fpv4-sp-d16
  -mfloat-abi=softfp
  -Ilib/FreeRTOS/include
  -Ilib/FreeRTOS/CMSIS_RTOS_V2
  -Ilib/FreeRTOS/portable/GCC/ARM_CM4F
  -Iinclude
; link FreeRTOS as objectf files, not as
; archives. otherwise weak ISR functions
; don't get linked properly!
lib_archive = no
; fix for RAM size / initial SP.
; see https://community.platformio.org/t/arm-versus-thumb/23540/
; actually **not** needed because we have selected a fixed linkerfile!!
;board_upload.maximum_ram_size = 131072

Note:

• This conversion process and the needed build flags are nothing new
  • outlined in many forum threads
  • automatic conversions tools like https://github.com/ussserrr/stm32pio exist that do the exact same thing
• board_build.stm32cube.custom_config_header is needed, the default stm32h7xx_hal_conf.h supplied by PlatformIO declares a 25MHz HSE input frequency when the Nucleo board has a 8MHz one. Alternatively, add -DHSE_VALUE=8000000UL to the build_flags.
• No need to copy Core\Startup, PlatforrmIO already has the startup file and compiles it in.
• same goes for Drivers\CMSIS and Drivers\STM32H7xx_HAL_Driver