PN532 NFC

// PN532 NFC on Arduino Uno: wiring and a free simulation at https://www.tinkered.ai/components/pn532-nfc
// PN532 V3 module in I2C mode on an Arduino Uno: SDA A4, SCL A5, address 0x24
#include <Wire.h>
#include <Adafruit_PN532.h>

// The constructor wants IRQ and reset pins; in I2C mode the library reads the PN532's
// ready byte instead, so D2 and D3 stay unconnected here.
Adafruit_PN532 nfc(2, 3, &Wire);

void setup() {
  Serial.begin(115200);
  nfc.begin();
  uint32_t version = nfc.getFirmwareVersion();
  if (!version) {
    Serial.println(F("PN532 not found: check the I2C switch and wiring"));
    while (true) {}
  }
  Serial.print(F("Found PN5"));
  Serial.print((version >> 24) & 0xFF, HEX);
  Serial.print(F(" firmware "));
  Serial.print((version >> 16) & 0xFF);
  Serial.print('.');
  Serial.println((version >> 8) & 0xFF);
  nfc.SAMConfig(); // normal reader mode
  Serial.println(F("Tap a card..."));
}

void loop() {
  uint8_t uid[7];
  uint8_t uidLength;
  if (nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength, 1000)) {
    Serial.print(F("Card UID:"));
    for (uint8_t i = 0; i < uidLength; i++) {
      Serial.print(uid[i] < 0x10 ? F(" 0") : F(" "));
      Serial.print(uid[i], HEX);
    }
    Serial.println();
    delay(1000);
  }
}

// PN532 NFC on ESP32 DevKit V1: wiring and a free simulation at https://www.tinkered.ai/components/pn532-nfc
// PN532 V3 module in I2C mode on an ESP32 DevKit V1: SDA GPIO21, SCL GPIO22, address 0x24
#include <Wire.h>
#include <Adafruit_PN532.h>

// IRQ and reset pins for the constructor; unconnected, the library polls the ready byte over I2C.
Adafruit_PN532 nfc(26, 27, &Wire);

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22); // SDA, SCL
  nfc.begin();
  uint32_t version = nfc.getFirmwareVersion();
  if (!version) {
    Serial.println("PN532 not found: check the I2C switch and wiring");
    while (true) { delay(100); }
  }
  Serial.printf("Found PN5%02X firmware %u.%u\n", (unsigned)((version >> 24) & 0xFF), (unsigned)((version >> 16) & 0xFF), (unsigned)((version >> 8) & 0xFF));
  nfc.SAMConfig();
  Serial.println("Tap a card...");
}

void loop() {
  uint8_t uid[7];
  uint8_t uidLength;
  if (nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength, 1000)) {
    Serial.print("Card UID:");
    for (uint8_t i = 0; i < uidLength; i++) Serial.printf(" %02X", uid[i]);
    Serial.println();
    delay(1000);
  }
}

// PN532 NFC on Raspberry Pi Pico: wiring and a free simulation at https://www.tinkered.ai/components/pn532-nfc
// PN532 V3 module in I2C mode on a Raspberry Pi Pico (arduino-pico): SDA GP4, SCL GP5, address 0x24
#include <Wire.h>
#include <Adafruit_PN532.h>

// IRQ and reset pins for the constructor; unconnected, the library polls the ready byte over I2C.
Adafruit_PN532 nfc(6, 7, &Wire);

void setup() {
  Serial.begin(115200);
  Wire.setSDA(4);
  Wire.setSCL(5);
  nfc.begin();
  uint32_t version = nfc.getFirmwareVersion();
  if (!version) {
    Serial.println("PN532 not found: check the I2C switch and wiring");
    while (true) { delay(100); }
  }
  Serial.print("Found PN5");
  Serial.print((version >> 24) & 0xFF, HEX);
  Serial.print(" firmware ");
  Serial.print((version >> 16) & 0xFF);
  Serial.print('.');
  Serial.println((version >> 8) & 0xFF);
  nfc.SAMConfig();
  Serial.println("Tap a card...");
}

void loop() {
  uint8_t uid[7];
  uint8_t uidLength;
  if (nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength, 1000)) {
    Serial.print("Card UID:");
    for (uint8_t i = 0; i < uidLength; i++) {
      Serial.print(uid[i] < 0x10 ? " 0" : " ");
      Serial.print(uid[i], HEX);
    }
    Serial.println();
    delay(1000);
  }
}