Introduction

This project is a personal initiative aimed at developing reusable firmware components for microcontroller platforms. It focuses on a modular and efficient General-Purpose Input/Output (GPIO) driver referred as the Digital Input/Output (DIO) driver on the documentation that can be easily adapted across various microcontroller families.

Version History

• v1.0: Initial release
• v1.1: Updated documentation, structural improvements and design by contract.

Software Architecture

The software architecture follows a layered approach. This design pattern separates low-level code (drivers or HALs), and application-specific code. A layered architecture promotes reusability and simplifies the portability between different applications or microcontrollers. The layered architecture can be seen in figure 1 and contains a driver and application layer operating on the hardware.

The Driver Layer provides all necessary low-level code to initialize and control hardware peripherals (e.g., GPIO pins, sensors, buttons).
The Application Layer contains no direct hardware manipulation but instead interacts with hardware through the exposed driver interfaces. This abstraction improves maintainability and facilitates hardware migration.

Coding Standards

The code is developed using a bare-metal approach and complies with industry-standard guidelines, particularly MISRA-C. Best practices in naming, formatting, documentation, and modular design are followed to ensure reliability and maintainability.

Project Description

This demonstration configures the user button (PC13) as an input. When pressed:

• The on-board LED (PA5) turns on.
• The external yellow LED (PB0) turns off via direct manipulation of the ODR register.

When released:

• The on-board LED turns off.
• The yellow LED turns on.

Additionally:

• The red LED (PA0) toggles (no delay implemented yet; behavior observable during debugging).
• The state of PC13 is read directly from the IDR register, and status messages are printed to the console accordingly.

Project Goals

• Provide a reusable GPIO driver for embedded applications.
• Ensure portability across different microcontroller platforms.
• Maintain compliance with professional coding standards (MISRA-C).

Development Tools

• Development Board: STM32 Nucleo-F401RE.
  
• IDE/Debugger: Visual Studio Code with PlatformIO extension.
• Toolchain: GNU ARM Embedded Toolchain.

Usage & Documentation

The project is fully documented using Doxygen. Inline comments offer detailed insights into function behavior and usage. The generated Doxygen documentation provides a structured and navigable reference for all code modules and components.

Glossary

• GPIO: General-Purpose Input/Output.
  
• DIO: Digital Input/Output.