STM32 Embedded C++ Framework 🚀

Overview

This repository demonstrates a clean, modern C++ architecture for embedded systems using STM32 microcontrollers. It decouples application logic and C++ drivers from the specific hardware capabilities and the STM32CubeIDE generated boilerplate.

The goal is to provide a portable, professional structure where C++ code remains board-agnostic, while STM32-specific configuration (generated by CubeMX) stays isolated in target folders.

Architecture

This project uses a Multi-Target Architecture:

• App/: Contains the high-level application logic. This code is 100% portable.
• Device/: Contains C++ wrapper classes for peripherals (GPIO, USART, etc.). These classes do not include specific MCU headers directly but use an adapter layer.
• Adapters/: The Hardware Abstraction Layer. mcu_adapter.h selects the correct Low-Level (LL) drivers based on the selected target.
• Targets/: Contains board-specific implementations. Each folder here corresponds to a complete STM32CubeIDE project (including .ioc, Core, Drivers and startup code).

Directory Structure

/
├── App/                # Application Logic (Portable)
│   ├── Inc/
│   └── Src/
├── Device/             # C++ Drivers (Portable Wrappers)
│   ├── Inc/
│   └── Src/
├── Adapters/           # Hardware Abstraction Layer
│   └── Inc/
│       └── mcu_adapter.h
├── Library/            # 📚 External Libraries
├── Utils/              # 🛠 Helpers & C-to-C++ Bridge
└── Targets/            # 🎯 Board Specific Projects
    ├── Nucleo_L433/    # Complete CubeIDE Project for L433
    └── Nucleo_F446RE/  # STM32F446RE (planned)

Supported Targets

Target	MCU	Status
Nucleo_L433	STM32L433RBTx	✅ Active
Nucleo_F446RE	STM32F446RETx	🚧 Planned

Getting Started

1. Prerequisites

• STM32CubeIDE (latest version recommended)
• A supported Nucleo board (currently configured for Nucleo-L433RC)

2. Importing into STM32CubeIDE

⚠️ Important: Do not import the root folder!

1. Open STM32CubeIDE.
2. Select File > Open Projects from File System....
3. Click Directory... and navigate to STM32_Embedded_CPP/Targets/Nucleo_L433.
4. Click Finish.

The project structure should look like this:

3. Setting up linked resources

Since the source code (App, Device) lives outside the project folder, you need to ensure the linked resources are set up correctly if they appear broken. The project uses the variable ${PROJECT_LOC} to refer to files relative to the target folder.

If folders App, Device, Utils are missing in the Project Explorer:

1. Right-click the Project -> New -> Folder.

   

2. Click Advanced >> -> Check Link to alternate location (Linked Folder).

   

3. Enter the location using the project variable:

   • App -> ${PROJECT_LOC}/../../App
   • Device -> ${PROJECT_LOC}/../../Device
   • Utils -> ${PROJECT_LOC}/../../Utils
   • Adapters -> ${PROJECT_LOC}/../../Adapters

4. Add the Include paths to the project properties:

   • For C Paths:

     

   • For C++ Paths:

     

---

4. Build & Run

1. Connect your Nucleo Board.
2. Click Run (Green play button).
3. The Application should blink the LED and print to UART/LPUART.

How to Work with This Repo

Modifying Application Code

Work primarily in the App/ folder. This is where your main loop (App_Run), initialization (App_Init), and business logic reside.

Adding New Drivers

Work in Device/.

1. Create your C++ wrapper class (MyDriver.h/.cpp).
2. Include mcu_adapter.h instead of specific stm32l4xx_ll_*.h files.
3. If a specific LL driver is missing, add it to mcu_adapter.h.

Adding a New Board (Target)

1. Create a new folder in Targets/ (e.g., Nucleo_F446).
2. Generate a new project using STM32CubeMX (or create a new STM32 Project in IDE) inside that folder.
3. Recommended: Select "LL" (Low Layer) drivers for peripherals managed by Device/ classes (like GPIO, UART) to maintain efficiency. However, you can mixed LL and HAL drivers if needed (e.g., using HAL for USB/Ethernet).
4. Setup Linked Resources & Includes: Repeat the steps from Getting Started -> 3. Setting up linked resources to:
   • Add the linked folders (App, Device, Utils, Adapters).
   • Add the C and C++ Include Paths.
5. Update Adapters/Inc/mcu_adapter.h to support the new MCU family (add #ifdef STM32F4...).

Available Drivers & Examples

Drivers

Driver	Header	Description
GPIO	Device/Inc/gpio.h	Digital output, input and EXTI interrupt callbacks
USART	Device/Inc/usart.h	Type-safe TX driver with interrupt-driven circular buffer

Examples

#	Example	Description
01	GPIO_Blinky	LED toggle using GPIOOutput
02	USART_HelloWorld	LPUART1 TX with error handling and formatted output

Contributing

Contributions are welcome! Please read CONTRIBUTING.md for coding standards and guidelines. If you port this to a new board, submit a PR with the new folder in Targets/.

License

MIT License. See LICENSE file for details.