Kickstart example to get PlatformIO to work with a STM32CubeMX generated project.

stm32_platformio.ini

; STM32 PlatformIO configuration file
;
;   This is a kickstart example to get PlatformIO to work with a STM32CubeMX generated project, which eliminates the need of
;   of the STM32CubeIDE. It also exclusively uses the driver files provided by CubeMX, rather than the outdated ones PlatformIO uses.
;
;   The following steps get you started:
;     1. Open the STM32CubeMX tool, find your board/MCU, and create a new project.
;     2. Go to the "Project Manager" tab and set the following:
;
;        Project        > Toolchain / IDE                                    : "Makefile"
;        Code Generator > STM32Cube MCU packages and embedded software packs : "Copy only the necessary library files"
;        Code Generator > Generated files                                    : "Generate peripheral initilization as a pair of '.c/.h' files per peripheral"
;
;     3. Configure your STM32 project to your likings and when done, click "Generate Code" to kick off the code generation.
;     4. STM32CubeMX will generate a couple of files, most importantly the .ioc, .s and .ld files. 
;        It will also copy the necessary library files into "Drivers/" and user code into "Core/"
;     5. Enter this directory with the VSCode PlatformIO terminal and run the following command:
;
;        PS C:\Path\To\CubeMX\Project> pio init
;
;     6. PlatformIO will generate an empty project structure inside the existing folder. You can delete the include/, lib/ and src/ folders since CubeMX
;        has it's own way of naming these.
;
;     7. Open the "platformio.ini" file and paste the contents of this file. You can then alter this configuration template by your likings, such as the
;        board you are using.
;
; More documentation on the PlatformIO .ini syntax can be found here: https://docs.platformio.org/page/projectconf.html

; Common PlatformIO configuration
[platformio]
include_dir = Core/Inc ; Directory that contains the user include files (more are defined in build_flags)
src_dir = . ; Directory that contains source files. Needs to be "." (current dir) so it takes the "startup_stm32xxxx.s" assembler file into account

; Common environment configuration
[env]
platform = ststm32 ; STM32 platform (https://registry.platformio.org/platforms/platformio/ststm32)

; Board-specific configuration
; IMPORTANT: do not include a "framework" here, otherwise it'll use PlatformIO's libraries instead of the ones copied by CubeMX (or you'll have duplicates)
[env:nucleo_l432kc]
board = nucleo_l432kc ; Which board to use
board_build.ldscript = STM32L432KCUx_FLASH.ld ; Path to the linker script generated by STM32CubeMX, necessary for linking the binary

; Additional build flags to pass to the compiler
; -I<dir> adds the given directory to the include paths. Add any STM32 driver include paths here 
build_flags =
    -IDrivers/CMSIS/Include
    -IDrivers/CMSIS/Device/ST/STM32L4xx/Include
    -IDrivers/STM32L4xx_HAL_Driver/Inc