Pi Pico GPIO HAL

Hardware abstraction layer for the Raspberry Pi Pico GPIO library, specifically designed to manage interrupt callbacks with per-pin callback support.

Overview

The main purpose of this library is to provide one callback per GPIO pin, allowing each callback to access its configuration context directly within the interrupt handler. This simplifies GPIO interrupt management compared to the standard Pico SDK, which uses a single global callback for all GPIO interrupts.

Features

• Per-Pin Callbacks: Register individual callbacks for each GPIO pin (up to 28 pins)
• Edge Detection: Support for both rising and falling edge interrupts
• Context Access: Each callback receives its interface structure, enabling access to application-specific context
• Simple API: Minimal wrapper around Pico SDK GPIO functions
• Helper Functions: Includes GPIO initialization helper for input pins with pull-up/pull-down configuration

Requirements

• Raspberry Pi Pico SDK

Configuration

The library can be configured using preprocessor defines:

• HAL_GPIO_MAX_NUM_INTERFACES: Maximum number of GPIO pins (default: 28)

Usage

For a complete working example demonstrating button interrupt handling with custom context data, see the examples/button_callback directory.

The example shows how to:

• Initialize the GPIO HAL
• Set up a custom context structure
• Register callbacks for button press events
• Access your custom data within the interrupt handler

Design Notes

• This library wraps only the IRQ-related GPIO functionality
• Users are expected to handle GPIO pin initialization (or use the provided helper function)
• One callback per GPIO pin limitation is by design for simplicity
• The library uses a static array to store interface pointers for fast lookup in interrupt context
• The CONTAINER_OF macro enables accessing custom context data from the base interface pointer

Status

This library is functional but considered a work in progress. Error handling is minimal in some functions.