PN532 — Near Field Communication (NFC) / RFID Controller Module

Overview

The PN532 is a highly integrated Near Field Communication (NFC) and 13.56 MHz RFID transceiver IC manufactured by NXP Semiconductors. Built around an 80C51 microcontroller core, it is the most versatile NFC controller for maker projects, supporting Reader/Writer mode, Peer-to-Peer (P2P) mode, and NFC Card Emulation mode.

Unlike basic RFID readers (such as the MFRC522 which only reads ISO 14443A MIFARE tags), the PN532 reads and writes NTAG213 / NTAG215 / NTAG216 NFC stickers, MIFARE Classic/Ultralight cards, FeliCa cards, and communicates directly with NFC-enabled smartphones (Android / Apple).

Quick reference


Module VCC	3.3 V to 5.0 V DC (onboard LDO)
Chip VDD / VBAT	2.7 V to 5.5 V DC
Carrier Frequency	13.56 MHz
Operating Range	Up to 50 mm (5 cm)
Supported Protocols	ISO/IEC 14443A/B, MIFARE 1K/4K, NTAG, FeliCa, ISO/IEC 18092 (NFCIP-1)
Operating Modes	Reader/Writer, P2P (NFCIP-1), Card Emulation (ISO 14443A)
Bus Interfaces	I2C (`0x24`), SPI, HSU (High-Speed UART 115200 baud)
Interface Selection	Onboard 2-bit DIP switch (`SEL0`, `SEL1`)

Pinout

Standard Red PN532 Breakout Board Header & DIP Switches

Pin	Name	Type	Description
1	`VCC`	Power	Supply voltage (+3.3 V to +5.0 V DC)
2	`GND`	Power	Ground (0 V)
3	`SDA` / `SS` / `TX`	Digital I/O	I2C `SDA` / SPI `SS` (CS) / HSU `TX`
4	`SCL` / `SCK` / `RX`	Digital Input	I2C `SCL` / SPI `SCK` / HSU `RX`
5	`MOSI`	Digital Input	SPI `MOSI`
6	`MISO`	Digital Output	SPI `MISO`
7	`IRQ`	Digital Output	Active-LOW Interrupt output (alerts MCU on card detection)
8	`RSTOUT` / `RST`	Digital Input	Hardware Reset pin

Bus Mode DIP Switch Configuration

The onboard 2-bit DIP switch (SEL0, SEL1) sets the active hardware communication interface:

Bus Mode	`SEL0` Switch Position	`SEL1` Switch Position	Hardware Protocol Used
I2C Mode	ON (0)	OFF (1)	I2C (Address `0x24`, `SDA` & `SCL` pins)
SPI Mode	OFF (1)	OFF (1)	4-Wire SPI (`SS`, `SCK`, `MOSI`, `MISO`)
HSU Mode	OFF (1)	ON (0)	High-Speed UART (`TX` & `RX` @ 115200 baud)

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Supply Voltage	$V_{BAT}$	2.7	3.3 / 5.0	5.5	V	DC
Active Transmit Current	$I_{TX}$	—	100	150	mA	RF field active
Power-Down Current	$I_{PD}$	—	1	5	µA	Hard power-down
RF Output Power	$P_{RF}$	—	100	—	mW	13.56 MHz antenna driver
Operating Distance	$d_{range}$	0	30	50	mm	Depends on antenna loop size

Wiring (I2C Mode Example)

PN532 Module Pin	→	Microcontroller (Arduino Uno / ESP32)
`VCC`		`5V` (or `3.3V`)
`GND`		`GND`
`SDA`		`SDA` (A4 on Uno, GPIO21 on ESP32)
`SCL`		`SCL` (A5 on Uno, GPIO22 on ESP32)
`IRQ`		GPIO Pin with Interrupt (e.g. D2 / GPIO4)

Note

DIP Switch Verification: For I2C mode, set DIP switch SEL0 = ON and SEL1 = OFF. Power cycle the PN532 module after changing DIP switches for new mode settings to take effect.

Common mistakes

Changing DIP switches without power cycle: The PN532 samples SEL0 and SEL1 pins ONLY during power-on reset. Changing DIP switch positions while powered on will not switch bus modes.
Forgetting I2C Pull-Up Resistors: If using I2C mode on bare custom PCBs, place $4.7\text{ k}\Omega$ pull-up resistors on SDA and SCL.
Card Emulation Limits: While the PN532 supports card emulation mode, iOS (Apple) and modern Android devices require Host Card Emulation (HCE) security keys. Emulating proprietary access cards may be restricted by smartphone OS security layers.

Notes

Compatible with Adafruit PN532 library, NFCBridge, and ESPHome pn532 component.

Interface	I2C, SPI, HSU (High Speed UART)
Supply	2.7–5.5 V
Package	40-pin HVQFN (6 x 6 mm) / Red PCB Breakout Board with DIP switches