Bare metal development nucleo_l011k4

This project shows how to build, flash and debug a bare metal application on the nucleo_l011k4 board, main characteristics :

• STM32L0
• ARM Cortex-M0+ core
• 16KB of Flash, 2KB of SRAM
• Embedded ST-Link for programming and debugging

Two build methods are available:

• Makefile
• CMake

Get repositoy + prerequisites

Clone with : git clone https://github.com/lucasdietrich/stm32l011k4-bare-metal.git --recurse-submodules

Prerequisites:

• cmake version 3.22.2
• arm-none-eabi-gcc (GNU Arm Embedded Toolchain 10.3-2021.10) 10.3.1 20210824 (release)
• Open On-Chip Debugger 0.11.0
• GNU gdb (GDB) Fedora 12.1-1.fc36

This project is fully integrated with Visual Studio Code, with extensions:

• ms-vscode.cpptools
• marus25.cortex-debug

Build, flash, debug

Build using cmake :

• cmake -DCMAKE_TOOLCHAIN_FILE=./toolchain-arm-none-eabi.cmake -DCMAKE_BUILD_TYPE=Debug -S . -B build

Build using Makefile :

• make --file=LegacyMakefile

Flash the application to the board :

• make flash

Debug:

• Select Target Debug VS code debug confication
• Ctrl + F5 in VS Code

Clean :

• make clean

Debug in QEMU using GDB

Run make qemu Select Qemu Debug VS code debug configuration and then press Ctrl + F5

Important note: as only the core is emulated in QEMU following parts should be disabled:

• Startup code for SRAM initialization
• Peripheral handling

Note

Topics:

• startup code
• mixing assembly and c code
• newlibc
• linker script
• STM32L0Cube drivers:
  • syslock
  • rcc
  • gpio
  • mco
  • uart
• Makefile / cmake
• debug

---

Sources

• Tutorials :

  • Bare Metal - From zero to blink
    • Tutorial github repo : https://github.com/joved-git/Bare_Metal_STM32
  • CMake on STM32 | Episode 1: the beginning
  • How to cross-compile for embedded with CMake like a champ
  • Video tutorial : STM32 Startup code, Bare metal - Part 3

• Others:

  • ARM Cortex-M bare-metal example code in C++ and CMake build
  • LVC21-308 Essential ARM Cortex M Debugging with GDB

• Example of ARM toolchain .cmake files :

  • https://github.com/vpetrigo/arm-cmake-toolchains
    • Especially : https://github.com/vpetrigo/arm-cmake-toolchains/blob/master/arm-gcc-toolchain.cmake
  • https://github.com/jobroe/cmake-arm-embedded
    • Especially : https://github.com/jobroe/cmake-arm-embedded/blob/master/toolchain-arm-none-eabi.cmake

• STM32Cube demo vscode

• Others personnal notes