CMake Basics

Every CMake-based application requires root CMakeLists.txt file in the root directory, that describes the project and provides input information for build system generation.

Essential things described in CMakeLists.txt file:

• Toolchain and compiler information
• Project name
• Source files to build with compiler, C, C++ or Assembly files
• List of include paths for compiler to find functions, defines, ... (-I)
• MCU sepecific compiler flags
• Linker script path
• Compilation defines, or sometimes called preprocessor defines (-D)

Prepare CMakeList.txt file

This is the main CMake setup file.

• Make new file in project root: CMakeList.txt

• Modify project name, linker file, and MCU sepecific setting.

• If you are using this project folder structure, you may run the bash script .\getIncludeList.sh and .\getSourceList.sh to auto scan /Application folder for generating CMake source list.

• Otherwise, you will have to modify /camke/IncludeList.cmake and /cmake/IncludeList.cmake.

CMakeList.txt

# Define needed CMake verion
cmake_minimum_required(VERSION 3.22)


# Setup cmake module path and compiler settings
list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake")
# Print current build type to console
message("Build type: "              ${CMAKE_BUILD_TYPE})
# Setup C and C++ version
set(CMAKE_C_STANDARD                11)
set(CMAKE_C_STANDARD_REQUIRED       ON)
set(CMAKE_C_EXTENSIONS              ON)
set(CMAKE_CXX_STANDARD              17)
set(CMAKE_CXX_STANDARD_REQUIRED     ON)
set(CMAKE_CXX_EXTENSIONS            ON)
set(CMAKE_EXPORT_COMPILE_COMMANDS   ON)
# Define current path for shorter reference below
set(PROJ_PATH                       ${CMAKE_CURRENT_SOURCE_DIR})
# Define .cmake module for toolchain compile flags that does holds true for all ARM projects
# This path is defined in the list() function above
set(CMAKE_TOOLCHAIN_FILE            gcc-arm-none-eabi)


# Project Name    --- MUST EDIT ---
project(L432KC-Template)
# Part of project name but made seperate for ease of editing project name
enable_language(C CXX ASM)
# Linker File     --- MUST EDIT ---
set(linker_script_SRC               ${PROJ_PATH}/Core/STM32L432KCUX_FLASH.ld)
# The use project name for binary file name
set(EXECUTABLE                      ${CMAKE_PROJECT_NAME})


# MCU Sepecific Setting    --- MUST EDIT ---
# Make multiple for various STM32 core
# This path is defined in the list() function above
include(STM32L432xx_HAL_PARA)

# .cmake module generated by using .\getIncludeList.sh and .\getSourceList.sh
# Those two file contains all the project source file list and include list
# This path is defined in the list() function above
include(SourceList)
include(IncludeList)


# Executable files
add_executable(${EXECUTABLE} ${source_list})
# Include paths
target_include_directories(${EXECUTABLE} PRIVATE ${include_list})
# Project symbols
target_compile_definitions(${EXECUTABLE} PRIVATE ${compiler_define})
# Compiler options
target_compile_options(${EXECUTABLE} PRIVATE
	${CPU_PARAMETERS}
	-Wall
	-Wpedantic
	-Wno-unused-parameter
)
# Linker options
target_link_options(${EXECUTABLE} PRIVATE
	-T${linker_script_SRC}
	${CPU_PARAMETERS}
	-Wl,-Map=${CMAKE_PROJECT_NAME}.map
	--specs=nosys.specs
	#-u _printf_float                # STDIO float formatting support
	-Wl,--start-group
	-lc
	-lm
	-lstdc++
	-lsupc++
	-Wl,--end-group
	-Wl,--print-memory-usage
)
# Execute post-build to print size
add_custom_command(TARGET ${EXECUTABLE} POST_BUILD
	COMMAND ${CMAKE_SIZE} $<TARGET_FILE:${EXECUTABLE}>
)
# Convert output to hex and binary
add_custom_command(TARGET ${EXECUTABLE} POST_BUILD
	COMMAND ${CMAKE_OBJCOPY} -O ihex $<TARGET_FILE:${EXECUTABLE}> ${EXECUTABLE}.hex
)
# Convert to bin file -> add conditional check?
add_custom_command(TARGET ${EXECUTABLE} POST_BUILD
	COMMAND ${CMAKE_OBJCOPY} -O binary $<TARGET_FILE:${EXECUTABLE}> ${EXECUTABLE}.bin
)