Welcome! This directory contains step-by-step guides for installing, building, and using the HF-PCAL95555 library – a hardware-agnostic C++ driver for the PCA9555 and PCAL9555A 16-bit I/O expanders.

The driver auto-detects which chip variant is connected and enables features accordingly. Standard PCA9555 features work on both chips; PCAL9555A-only features (pull resistors, drive strength, input latch, interrupt mask/status, output mode) degrade gracefully on a PCA9555.

📚 Documentation Structure

Getting Started

🛠️ Installation – How to integrate the driver into your project
⚡ Quick Start – Minimal working example to get you running
🔌 Hardware Setup – Wiring diagrams and pin connections

Integration

🔧 Platform Integration – Implement the CRTP I2C interface for your platform
⚙️ Configuration – Configuration options and Kconfig settings

Reference

📖 API Reference – Complete API documentation (43 methods)
💡 Examples – Detailed example walkthroughs (comprehensive test + LED animation)

Troubleshooting

🐛 Troubleshooting – Common issues and solutions

💡 Need Help?

🐛 Found a bug? Check the Troubleshooting guide
❓ Have questions? Review the API Reference
📝 Want to contribute? See the contributing guidelines in the main README