Documentation

// PN532 NFC Module V3 - Arduino Example (I2C mode)
// SDA->A4, SCL->A5, VCC->5V | S1=ON, S2=OFF
// Library: "Adafruit PN532" (Library Manager)

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

Adafruit_PN532 nfc(-1, -1, &Wire);   // I2C, no IRQ/RSTO pins needed

void setup() {
  Serial.begin(115200);
  nfc.begin();

  uint32_t version = nfc.getFirmwareVersion();
  if (!version) {
    Serial.println("Didn't find PN53x board - check S1/S2 and wiring");
    while (1);
  }
  Serial.print("Found PN5");
  Serial.println((version >> 24) & 0xFF, HEX);

  nfc.SAMConfig();                   // enable reader mode
  Serial.println("Tap a card or tag...");
}

void loop() {
  uint8_t uid[7];
  uint8_t uidLength;

  if (nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength, 500)) {
    Serial.print("Card UID: ");
    for (uint8_t i = 0; i < uidLength; i++) {
      if (uid[i] < 0x10) Serial.print("0");
      Serial.print(uid[i], HEX);
      if (i < uidLength - 1) Serial.print(":");
    }
    Serial.println();
    delay(1000);                     // debounce same-card reads
  }
}

// PN532 NFC Module V3 - ESP32 Example (I2C mode)
// SDA->GPIO 21, SCL->GPIO 22, VCC->3V3 | S1=ON, S2=OFF
// Library: "Adafruit PN532"

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

Adafruit_PN532 nfc(-1, -1, &Wire);

// Example whitelist: replace with your own card UID
const uint8_t DOOR_CARD[4] = {0xDE, 0xAD, 0xBE, 0xEF};

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);
  nfc.begin();

  if (!nfc.getFirmwareVersion()) {
    Serial.println("PN532 not found - check S1/S2 switches");
    while (1) delay(10);
  }
  nfc.SAMConfig();
  Serial.println("Tap a card or tag...");
}

void loop() {
  uint8_t uid[7];
  uint8_t len;

  if (nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &len, 500)) {
    Serial.print("UID: ");
    for (uint8_t i = 0; i < len; i++) {
      Serial.printf("%02X", uid[i]);
      if (i < len - 1) Serial.print(":");
    }

    bool match = (len == 4) && !memcmp(uid, DOOR_CARD, 4);
    Serial.println(match ? "  -> ACCESS GRANTED" : "  -> unknown card");
    delay(1000);
  }
}

#!/usr/bin/env python3
# PN532 NFC Module V3 - Raspberry Pi Example (I2C mode)
# SDA->GPIO2, SCL->GPIO3, VCC->3.3V | S1=ON, S2=OFF
# Install: pip3 install adafruit-circuitpython-pn532

import time
import board
import busio
from adafruit_pn532.i2c import PN532_I2C

i2c = busio.I2C(board.SCL, board.SDA)
pn532 = PN532_I2C(i2c, debug=False)

ic, ver, rev, support = pn532.firmware_version
print("Found PN532 firmware {}.{}".format(ver, rev))

pn532.SAM_configuration()
print("Tap a card or tag...")

seen = None
try:
    while True:
        uid = pn532.read_passive_target(timeout=0.5)
        if uid is not None:
            uid_str = ":".join("{:02X}".format(b) for b in uid)
            if uid_str != seen:
                print("Card UID:", uid_str)
                seen = uid_str
        else:
            seen = None
        time.sleep(0.1)
except KeyboardInterrupt:
    print("Stopped by user")

# PN532 NFC Module V3 - Pico MicroPython Example (SPI mode)
# SCK->GP2, MOSI->GP3, MISO->GP4, SS->GP5 | S1=OFF, S2=ON
# Driver: copy NFC_PN532.py (micropython PN532 SPI driver) to the Pico
#   from https://github.com/Carglglz/NFC_PN532 (save as NFC_PN532.py)

from machine import Pin, SPI
import NFC_PN532 as nfc_mod
import time

spi = SPI(0, baudrate=1000000,
          sck=Pin(2), mosi=Pin(3), miso=Pin(4))
cs = Pin(5, Pin.OUT, value=1)

nfc = nfc_mod.PN532(spi, cs)
ic, ver, rev, support = nfc.get_firmware_version()
print("Found PN532 firmware {}.{}".format(ver, rev))

nfc.SAM_configuration()
print("Tap a card or tag...")

while True:
    uid = nfc.read_passive_target(timeout=500)
    if uid:
        print("Card UID:", ":".join("{:02X}".format(b) for b in uid))
        time.sleep(1)
    time.sleep(0.1)