This is a NFC HAT based on PN532 operating in the 13.56MHz frequency range. It supports three communication interfaces: I2C, SPI, and UART. NFC (Near Field Communication) is a wireless technology allows contactless point-to-point data communication between devices within a short distance of 10 cm. It is widely used in applications such as access control system, smart tickets, meal card, etc. Based on the popular NFC controller PN532 with multi interface options, this HAT easily enable NFC function for your . Standard 40PIN GPIO extension header, supports series boards Onboard PN532 chip, supports various NFC/RFID cards like /NTAG2xx, etc. Three interface options: I2C, SPI, and UART, configured via and switches Breakout control pins, for easily connecting with host boards like STM32/ Comes with development resources and manual (examples for Raspberry Python/C, STM32, ) Specifications NFC controller: PN532 Operating voltage: 3.3V/5V Operating frequency: 13.56MHz Communication interfaces: I2C, SPI, UART (default) Default baudrate: 115200 Operating modes: reader/writing mode supporting ISO/IEC 14443A / IC scheme reader/writing mode supporting FeliCa scheme reader/writing mode supporting ISO/IEC 14443B scheme card operation mode supporting ISO 14443A / IC scheme card operation mode supporting FeliCa scheme ISO/IEC18092, ECM340 point-to-point colour:blue Material:plastic Package Contents: 1x PN532 NFC HAT Module 1x IC Classic Card Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.