PN5180 NFC Reader – Fix Duplicated UID Issue

📋 Overview

A robust solution for reading NFC cards (ISO14443A) using the PN5180 module, specifically addressing a critical bug in standard libraries that causes duplicated UID readings.

This implementation ensures that each NFC card always returns its correct, unique UID.

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⚠️ The Problem: Duplicated UID Reading

When using standard PN5180 libraries, users often encounter critical issues:

• Different cards showing the same UID
  Multiple distinct cards return identical UID values

• Same card showing different UIDs
  A single card returns varying UIDs on consecutive reads

• Invalid UIDs
  Readings of all zeros (0x00) or all ones (0xFF) that do not correspond to real cards

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🔍 Root Cause Analysis

The core problem lies in the standard PN5180 library’s insufficient handling of internal buffers and validation:

• Insufficient FIFO buffer clearing
  readCardSerial() does not properly reset the PN5180 internal FIFO before new reads

• Missing data validation
  No validation of ATQA and SAK responses before processing UID data

• Incomplete error checking
  Manufacturer code and UID structure are not verified, allowing corrupted data

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🛠️ Solution: Enhanced Direct Buffer Processing

Instead of relying on the flawed readCardSerial() function, this project uses a direct approach based on activateTypeA() with strict validation.

Key Improvements

• Direct FIFO buffer management
• Comprehensive ATQA and SAK validation
• UID structure and manufacturer code verification
• Enhanced error detection with explicit status handling
• Periodic hardware reset to ensure a clean PN5180 state

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📁 File Structure

• PN5180-NFC-Reader/
• ├── src/
• │ └── PN5180_reader.ino # Main application
• ├── inc/
• │ └── PN5180/ # PN5180 library
• └── README.md # This file

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🚀 Quick Start

🧱 Hardware Requirements

• PN5180 NFC Reader Module
• ESP32 Development Board (or Arduino with sufficient GPIOs)
• ISO14443A NFC Cards/Tags, including:
  • MIFARE Classic
  • MIFARE Ultralight
  • NTAG series

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🔧 Wiring Diagram

PN5180 → ESP32

PN5180 Pin	ESP32 Pin
NSS	GPIO 16
BUSY	GPIO 5
RST	GPIO 17
SCK	GPIO 18
MOSI	GPIO 23
MISO	GPIO 19
VCC	3.3V
GND	GND

⚠ Note:
Never swap NSS (GPIO 16) and BUSY (GPIO 5) – this will cause PN5180 communication failure.

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💻 Software Installation

1️⃣ Arduino IDE

• Install Arduino IDE 1.8.x or later
• Install ESP32 Board Support Package

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2️⃣ PN5180 Library

• Install PN5180 library by tueddy
  🔗 https://github.com/tueddy/PN5180-Library

• Add library via: Sketch → Include Library → Add .ZIP Library

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3️⃣ Build & Upload

1. Clone or download this repository
2. Open PN5180_reader.ino in Arduino IDE
3. Select:
   • Board: ESP32 Dev Module
   • Correct COM Port
4. Upload the sketch

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🤝 Contributing

Contributions are welcome!
Please open an issue or submit a pull request.