How to Use Adafruit PN532 Breakout: Examples, Pinouts, and Specs

The Adafruit PN532 Breakout Board is a versatile and user-friendly NFC/RFID controller that enables wireless communication for a variety of applications. Based on the widely-used PN532 chip, this breakout board is designed to read and write NFC tags, interface with NFC-enabled devices, and facilitate secure transactions. With an onboard 3.3V regulator and level shifting, it is compatible with a broad range of microcontrollers, including both 3.3V and 5V systems, such as the Arduino UNO.

• Contactless payment systems
• Access control
• Identification and authentication
• NFC tag reading and writing
• Peer-to-peer communication between NFC devices

• Operating Voltage: 3.3V to 5V (with onboard regulator)
• Operating Current: 100mA (typical)
• Frequency: 13.56MHz
• Supported Protocols: ISO/IEC 14443 Type A and B, FeliCa, and MIFARE cards
• Interface: I2C, SPI, and HSU (High-Speed UART)
• Range: Up to 7cm (depending on antenna geometry and card type)

1. Power Connections: Connect VCC to a 3.3V or 5V supply and GND to the ground of your microcontroller.
2. Data Connections: Choose between I2C, SPI, or HSU for communication and connect the respective pins to your microcontroller.
3. Antenna: Ensure the antenna area is unobstructed for optimal range.
4. Reset: Connect RSTPD_N to a digital pin for manual reset control, if required.

• Use level shifting for 5V microcontrollers to protect the PN532.
• Place the breakout board away from metal surfaces to avoid interference.
• For I2C communication, ensure pull-up resistors are in place if not already provided by your microcontroller.
• Avoid bending the antenna or subjecting it to physical stress.

#include <Wire.h>
#include <Adafruit_PN532.h>

// If using the I2C interface, define SDA and SCL pins
#define SDA_PIN 2
#define SCL_PIN 3

// Create an instance of the Adafruit_PN532 class
Adafruit_PN532 nfc(SDA_PIN, SCL_PIN);

void setup(void) {
  Serial.begin(115200);
  Serial.println("Hello! Scan a NFC tag!");

  nfc.begin();

  uint32_t versiondata = nfc.getFirmwareVersion();
  if (!versiondata) {
    Serial.print("Didn't find PN53x board");
    while (1); // halt
  }

  // Configure board to read RFID tags
  nfc.SAMConfig();
}

void loop(void) {
  uint8_t success;
  uint8_t uid[] = { 0, 0, 0, 0, 0, 0, 0 }; // Buffer to store the returned UID
  uint8_t uidLength; // Length of the UID (4 or 7 bytes depending on ISO14443A card type)

  // Wait for an ISO14443A type card (Mifare, etc.). When one is found, 'uid' will be populated
  success = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength);

  if (success) {
    // Display some basic information about the card
    Serial.println("Found an ISO14443A card");
    Serial.print("UID Length: ");Serial.print(uidLength, DEC);Serial.println(" bytes");
    Serial.print("UID Value: ");
    for (uint8_t i=0; i < uidLength; i++) {
      Serial.print(" 0x");Serial.print(uid[i], HEX);
    }
    Serial.println("");
    // Wait 1 second before continuing
    delay(1000);
  }
}

• No response from the module: Ensure power connections are correct and the microcontroller pins are properly configured.
• Inconsistent tag reads: Check for any obstructions or interference near the antenna area.
• Communication errors: Verify the correct interface (I2C/SPI/HSU) is selected and properly connected.

• Double-check wiring, especially the SDA and SCL lines for I2C, and MOSI, MISO, and SCK for SPI.
• Ensure the library used matches the communication protocol selected.
• Reset the PN532 module using the RSTPD_N pin if the module becomes unresponsive.

Q: Can the Adafruit PN532 Breakout Board be used with a 5V microcontroller like an Arduino UNO?

A: Yes, the board has a built-in level shifter and regulator, making it compatible with 5V systems.

Q: What is the maximum range of the NFC communication?

A: The maximum range is up to 7cm, but this can vary based on antenna design and environmental factors.

Q: How do I know if the board is powered and functioning correctly?

A: Upon powering up, the board's firmware version can be read as a basic check. If the firmware version is returned, the board is functioning correctly.

Q: Can the board read all types of NFC tags?

A: The board supports a wide range of NFC tags, including ISO/IEC 14443 Type A and B, FeliCa, and MIFARE cards. However, compatibility with all NFC tag types is not guaranteed.