Utilizing the SunFounder PN532 NFC RFID Module Kit to control physical access to a building. The Azure Sphere supports universal asynchronous receiver-transmitter (UART) for serial communication. The UART provides the ability to send and receive data over a serial port to a peripheral device. The SunFounder peripheral was selected to show utilization of low cost RFC/RFID sensor (less than $12.00 US).
The NFC tag is a passive data stores which can be read by the PN532 device. The PN532 may also write to a writable NFC/RFID tag.
This will be an opportunity to explore the library requirements for interfacing this peripheral to the Avnet Azure Sphere MT3620 Starter Kit.
The SunFounder PN532 features:
Supports I2C, SPI and HSU (High-Speed UART), mode is selected by switch position (SEL1, SEL2).
Integratation of 3.3V voltage regulator providing a choice of 3.3V or 5V
Published distance for reading RFID is 3 cm / 1 in
According to the vendors documentation the UART and I2C modes share the same port.
My original thoughts were to use the UART Pmod, but after reading the documentation for the PN532, I want to explore the possibility of utilizing the grove connection. The diagram of the connection of the UNO board shows SDA connecting to TxD and SCL connecting RxD.
1. Verify the PN532 works using I2C with Raspberry PI / UNO using vendor provided documentation.
2. Explore the existing libraries for I2C/UART for use with the PN532.