About

This project is used to develop applications for the STM32 - ST's ARM Cortex-Mx MCUs. It uses cmake and GCC, along with newlib (libc), STM32Cube. Supports F0 F1 F2 F3 F4 F7 G0 G4 H7 L0 L1 L4 L5 WB WL device families.

Requirements

• cmake >= 3.16
• GCC toolchain with newlib (optional).
• STM32Cube package for appropriate STM32 family.

Project contains

• CMake toolchain file, that configures cmake to use the arm toolchain: cmake/stm32_gcc.cmake.
• CMake module that contains useful functions: cmake/stm32/common.cmake
• CMake modules that contains information about each family - RAM/flash sizes, CPU types, device types and device naming (e.g. it can tell that STM32F407VG is F4 family with 1MB flash, 128KB RAM with CMSIS type F407xx)
• CMake toolchain file that can generate a tunable linker script cmake/stm32/linker_ld.cmake
• CMake module to find and configure CMSIS library cmake/FindCMSIS.cmake
• CMake module to find and configure STM32 HAL library cmake/FindHAL.cmake
• CMake modules for various libraries/RTOSes
• CMake project template and examples
• Some testing project to check cmake scripts working properly tests

Examples

• template (examples/template) - project template, empty source linked compiled with CMSIS.
• custom-linker-script (examples/custom-linker-script) - similar to template but using custom linker script.
• fetch-cube (examples/fetch-cube) - example of using FetchContent for fetching STM32Cube from ST's git.
• fetch-cmsis-hal (examples/fetch-cmsis-hal) - example of using FetchContent for fetching STM32 CMSIS and HAL from ST's git.
• blinky (examples/blinky) - blink led using STM32 HAL library and SysTick. It will compile a project for the F4 family by default, but you can also compile for the L0 and F1 family by passing L0_EXAMPLE=ON or F1_EXAMPLE=ON to the CMake generation call.
• freertos (examples/freertos) - blink led using STM32 HAL library and FreeRTOS.

Usage

First of all you need to configure toolchain and library paths using CMake variables. There are generally three ways to do this:

1. Pass the variables through command line during cmake run with passed to CMake with -D<VAR_NAME>=...
2. Set the variables inside your CMakeLists.txt
3. Pass these variables to CMake by setting them as environmental variables.

The most important set of variables which needs to be set can be found in the following section.

Configuration

These configuration options need to be set for the build process to work properly:

• STM32_TOOLCHAIN_PATH - where toolchain is located, default: /usr
• STM32_CUBE_<FAMILY>_PATH - path to STM32Cube directory, where <FAMILY> is one of F0 F1 F2 F3 F4 F7 G0 G4 H7 L0 L1 L4 L5 WB WL default: /opt/STM32Cube<FAMILY>

These configuration variables are optional:

• TARGET_TRIPLET - toolchain target triplet, default: arm-none-eabi
• FREERTOS_PATH - Path to the FreeRTOS kernel when compiling with a RTOS. Does not need to be specified when using CMSIS

Helper script on Unix shells

If you have access to a Unix shell, which is the default terminal on Linux, or tools like MinGW64 or git bash on Windows, you can write a small path_helper.sh script like this:

export STM32_TOOLCHAIN_PATH="<ToolchainPath>"
export TARGET_TRIPLET=arm-none-eabi
export STM32_CUBE_<FAMILY>_PATH="<PathToCubeRoot>"

and then use . path_helper.sh to set up the environment for the local terminal instance in one go.

Helper script in Powershell

On Windows, you can use a Powershell script path_helper.ps1to set up the environment:

$env:STM32_TOOLCHAIN_PATH = "<ToolchainPath>"
$env:TARGET_TRIPLET = arm-none-eabi
$env:STM32_CUBE_<FAMILY>_PATH="<PathToCubeRoot>"

Common usage

First thing that you need to do after toolchain configuration in your CMakeLists.txt script is to find CMSIS package:

find_package(CMSIS [CMSIS_version] COMPONENTS STM32F4 REQUIRED)

You can specify STM32 family or even specific device (STM32F407VG) in COMPONENTS or omit COMPONENTS totally - in that case stm32-cmake will find ALL sources for ALL families and ALL chips (you'll need ALL STM32Cube packages somewhere).

[CMSIS_version] is an optional version requirement. See find_package documentation. This parameter does not make sense if multiple STM32 families are requested.

Each STM32 device can be categorized into family and device type groups, for example STM32F407VG is device from F4 family, with type F407xx.

*Note: Some devices have two different cores (e.g. STM32H7 has Cortex-M7 and Cortex-M4). For those devices the name used must include the core name e.g STM32H7_M7 and STM32H7_M4. STM32WB is a multi-cores device even if the second core is not accessible by end user.

CMSIS consists of three main components:

• Family-specific headers, e.g. stm32f4xx.h
• Device type-specific startup sources (e.g. startup_stm32f407xx.s)
• Device-specific linker scripts which requires information about memory sizes

stm32-cmake uses modern CMake features notably imported targets and target properties. Every CMSIS component is CMake's target (aka library), which defines compiler definitions, compiler flags, include dirs, sources, etc. to build and propagate them as dependencies. So in a simple use-case all you need is to link your executable with library CMSIS::STM32::<device>:

add_executable(stm32-template main.c)
target_link_libraries(stm32-template CMSIS::STM32::F407VG)

That will add include directories, startup source, linker script and compiler flags to your executable.

CMSIS creates the following targets:

• CMSIS::STM32::<FAMILY> (e.g. CMSIS::STM32::F4) - common includes, compiler flags and defines for family
• CMSIS::STM32::<TYPE> (e.g. CMSIS::STM32::F407xx) - common startup source for device type, depends on CMSIS::STM32::<FAMILY>
• CMSIS::STM32::<DEVICE> (e.g. CMSIS::STM32::F407VG) - linker script for device, depends on CMSIS::STM32::<TYPE>

So, if you don't need linker script, you can link only CMSIS::STM32::<TYPE> library and provide your own script using stm32_add_linker_script function

Note: Because of some families multi-cores architecture, all targets also have a suffix (e.g. STM32H7 has ::M7 or ::M4). For example, targets created for STM32H747BI will look like CMSIS::STM32::H7::M7, CMSIS::STM32::H7::M4, CMSIS::STM32::H747BI::M7, CMSIS::STM32::H747BI::M4, etc.

The GCC C/C++ standard libraries are added by linking the library STM32::NoSys. This will add the --specs=nosys.specs to compiler and linker flags. If you want to use C++ on MCUs with little flash, you might instead want to link the newlib-nano to reduce the code size. You can do so by linking STM32::Nano, which will add the --specs=nano.specs flags to both compiler and linker. Keep in mind that when using STM32::Nano, by default you cannot use floats in printf/scanf calls, and you have to provide implementations for several OS interfacing functions (_sbrk, _close, _fstat, and others). You can enable printf/scanf floating point support with newlib-nano by linking against STM32::Nano::FloatPrint and/or STM32::Nano::FloatScan. It is also possible to combine STM32::Nano and STM32::NoSys to have the benefits of reduced code size while not being forced to implement system calls.

HAL

STM32 HAL can be used similar to CMSIS.

find_package(HAL [HAL_version] COMPONENTS STM32F4 REQUIRED)
set(CMAKE_INCLUDE_CURRENT_DIR TRUE)

CMAKE_INCLUDE_CURRENT_DIR here because HAL requires stm32<family>xx_hal_conf.h file being in include headers path.

[HAL_version] is an optional version requirement. See find_package documentation. This parameter does not make sense if multiple STM32 families are requested.

HAL module will search all drivers supported by family and create the following targets:

• HAL::STM32::<FAMILY> (e.g. HAL::STM32::F4) - common HAL source, depends on CMSIS::STM32::<FAMILY>
• HAL::STM32::<FAMILY>::<DRIVER> (e.g. HAL::STM32::F4::GPIO) - HAL driver , depends on HAL::STM32::<FAMILY>
• HAL::STM32::<FAMILY>::<DRIVER>Ex (e.g. HAL::STM32::F4::ADCEx) - HAL Extension driver , depends on HAL::STM32::<FAMILY>::<DRIVER>
• HAL::STM32::<FAMILY>::LL_<DRIVER> (e.g. HAL::STM32::F4::LL_ADC) - HAL LL (Low-Level) driver , depends on HAL::STM32::<FAMILY>

Note: Targets for multi-cores devices will look like HAL::STM32::<FAMILY>::<CORE>, HAL::STM32::<FAMILY>::<CORE>::<DRIVER>, etc.

Here is typical usage:

add_executable(stm32-blinky-f4 blinky.c stm32f4xx_hal_conf.h)
target_link_libraries(stm32-blinky-f4 
    HAL::STM32::F4::RCC
    HAL::STM32::F4::GPIO
    HAL::STM32::F4::CORTEX
    CMSIS::STM32::F407VG
    STM32::NoSys 
)

Building

    $ cmake -DCMAKE_TOOLCHAIN_FILE=<path_to_gcc_stm32.cmake> -DCMAKE_BUILD_TYPE=Debug <path_to_sources>
    $ make

Linker script & variables

CMSIS package will generate linker script for your device automatically (target CMSIS::STM32::<DEVICE>). To specify a custom linker script, use stm32_add_linker_script function.

Useful CMake functions

• stm32_get_chip_info(<chip> [FAMILY <family>] [TYPE <type>] [DEVICE <device>]) - classify device using name, will return device family (into <family> variable), type (<type>) and canonical name (<device>, uppercase without any package codes)
• stm32_get_memory_info((CHIP <chip>)|(DEVICE <device> TYPE <type>) [FLASH|RAM|CCRAM|STACK|HEAP] [SIZE <size>] [ORIGIN <origin>]) - get information about device memories (into <size> and <origin>). Linker script generator uses values from this function
• stm32_print_size_of_target(<target>) - Print the application sizes for all formats
• stm32_generate_binary_file(<target>) - Generate the binary file for the given target
• stm32_generate_hex_file(<target>) - Generate the hex file for the given target

In the following functions, you can also specify mutiple families.

• stm32_get_devices_by_family(STM_DEVICES [FAMILY families...]) - return into STM_DEVICES all supported devices by family (or all devices if FAMILY is omitted)
• stm32_print_devices_by_family([FAMILY families...]) - Print all supported devices by family (or all devices if FAMILY is omitted)

Additional CMake modules

stm32-cmake contains additional CMake modules for finding and configuring various libraries and RTOSes used in the embedded world.

FreeRTOS

cmake/FindFreeRTOS - finds FreeRTOS sources in location specified by FREERTOS_PATH (default: /opt/FreeRTOS) variable and format them as IMPORTED targets. FREERTOS_PATH can be either the path to the whole FreeRTOS/FreeRTOS github repo, or the path to FreeRTOS-Kernel (usually located in the subfolder FreeRTOS on a downloaded release). You can supply FREERTOS_PATH as an environmental variable as well.

Typical usage:

find_package(FreeRTOS COMPONENTS ARM_CM4F REQUIRED)
target_link_libraries(... FreeRTOS::ARM_CM4F)

The following FreeRTOS ports are supported: ARM_CM0, ARM_CM3, ARM_CM4F, ARM_CM7.

Other FreeRTOS libraries:

• FreeRTOS::Coroutine - co-routines (croutines.c)
• FreeRTOS::EventGroups - event groups (event_groups.c)
• FreeRTOS::StreamBuffer - stream buffer (stream_buffer.c)
• FreeRTOS::Timers - timers (timers.c)
• FreeRTOS::Heap::<N> - heap implementation (heap_<N>.c), <N>: [1-5]