ESP32-Wroom-32无法识别PN532 NFC模块的排查求助

问题描述 #

使用ESP32-Wroom-32连接PN532 NFC模块时，无论切换I2C/SPI通信方式、修改引脚配置或更换引脚，均输出Didn't find PN53x board，模块无法被识别。测试代码如下：

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

// If using the breakout with SPI, define the pins for SPI communication.
#define PN532_SCK  (16)
#define PN532_MOSI (25)
#define PN532_SS   (17)
#define PN532_MISO (26)

// Uncomment just _one_ line below depending on how your breakout or shield
// is connected to the Arduino:

// Use this line for a breakout with a software SPI connection (recommended):
Adafruit_PN532 nfc(16, 26, 25, 17);

// Use this line for a breakout with a hardware SPI connection.  Note that
// the PN532 SCK, MOSI, and MISO pins need to be connected to the Arduino's
// hardware SPI SCK, MOSI, and MISO pins.  On an Arduino Uno these are
// SCK = 13, MOSI = 11, MISO = 12.  The SS line can be any digital IO pin.
//Adafruit_PN532 nfc(PN532_SS);

// Or use this line for a breakout or shield with an I2C connection:
//Adafruit_PN532 nfc(PN532_IRQ, PN532_RESET);

// Or use hardware Serial:
//Adafruit_PN532 nfc(PN532_RESET, &Serial1);

void setup(void) {
  Serial.begin(115200);
  while (!Serial) delay(10); // for Leonardo/Micro/Zero

  Serial.println("Hello!");

  nfc.begin();
 delay(1000);
  uint32_t versiondata = nfc.getFirmwareVersion();
  if (! versiondata) {
    Serial.print("Didn't find PN53x board");
    while (1); // halt
  }
  // Got ok data, print it out!
  Serial.print("Found chip PN5"); Serial.println((versiondata>>24) & 0xFF, HEX);
  Serial.print("Firmware ver. "); Serial.print((versiondata>>16) & 0xFF, DEC);
  Serial.print('.'); Serial.println((versiondata>>8) & 0xFF, DEC);

  Serial.println("Waiting for an ISO14443A Card ...");
}


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 cards (Mifare, etc.).  When one is found
  // 'uid' will be populated with the UID, and uidLength will indicate
  // if the uid is 4 bytes (Mifare Classic) or 7 bytes (Mifare Ultralight)
  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: ");
    nfc.PrintHex(uid, uidLength);
    Serial.println("");

    if (uidLength == 4)
    {
      // We probably have a Mifare Classic card ...
      Serial.println("Seems to be a Mifare Classic card (4 byte UID)");

      // Now we need to try to authenticate it for read/write access
      // Try with the factory default KeyA: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF
      Serial.println("Trying to authenticate block 4 with default KEYA value");
      uint8_t keya[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };

      // Start with block 4 (the first block of sector 1) since sector 0
      // contains the manufacturer data and it's probably better just
      // to leave it alone unless you know what you're doing
      success = nfc.mifareclassic_AuthenticateBlock(uid, uidLength, 4, 0, keya);

      if (success)
      {
        Serial.println("Sector 1 (Blocks 4..7) has been authenticated");
        uint8_t data[16];

        // If you want to write something to block 4 to test with, uncomment
        // the following line and this text should be read back in a minute
        //memcpy(data, (const uint8_t[]){ 'a', 'd', 'a', 'f', 'r', 'u', 'i', 't', '.', 'c', 'o', 'm', 0, 0, 0, 0 }, sizeof data);
        // success = nfc.mifareclassic_WriteDataBlock (4, data);

        // Try to read the contents of block 4
        success = nfc.mifareclassic_ReadDataBlock(4, data);

        if (success)
        {
          // Data seems to have been read ... spit it out
          Serial.println("Reading Block 4:");
          nfc.PrintHexChar(data, 16);
          Serial.println("");

          // Wait a bit before reading the card again
          delay(1000);
        }
        else
        {
          Serial.println("Ooops ... unable to read the requested block.  Try another key?");
        }
      }
      else
      {
        Serial.println("Ooops ... authentication failed: Try another key?");
      }
    }

    if (uidLength == 7)
    {
      // We probably have a Mifare Ultralight card ...
      Serial.println("Seems to be a Mifare Ultralight tag (7 byte UID)");

      // Try to read the first general-purpose user page (#4)
      Serial.println("Reading page 4");
      uint8_t data[32];
      success = nfc.mifareultralight_ReadPage (4, data);
      if (success)
      {
        // Data seems to have been read ... spit it out
        nfc.PrintHexChar(data, 4);
        Serial.println("");

        // Wait a bit before reading the card again
        delay(1000);
      }
      else
      {
        Serial.println("Ooops ... unable to read the requested page!?");
      }
    }
  }
}

排查与解决步骤 #

1. 硬件连接检查 #

• 供电要求：PN532仅支持3.3V供电，严禁接5V。确保ESP32的3.3V引脚能提供足够电流（PN532峰值约100mA），若ESP32供电不足，可改用外部3.3V电源模块。
• 引脚对应：
  • SPI模式：优先使用ESP32硬件SPI引脚，对应关系为SCK→18、MOSI→23、MISO→19，SS引脚可自定义（如17），同时必须连接GND。
  • I2C模式：使用ESP32默认I2C引脚SDA→21、SCL→22，需额外连接PN532的RESET引脚（如接ESP32的4号引脚），IRQ引脚可选（推荐接2号引脚）。
• 接线质量：检查所有杜邦线是否松动、引脚是否虚焊，重点确认GND连接可靠。

2. 代码配置修正 #

SPI模式推荐方案（硬件SPI）

使用ESP32硬件SPI稳定性优于软件SPI，修改代码如下：

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

// 硬件SPI配置：SS引脚自定义为17
#define PN532_SS   17

// 初始化硬件SPI连接
Adafruit_PN532 nfc(PN532_SS);

void setup(void) {
  Serial.begin(115200);
  while (!Serial) delay(10); 

  Serial.println("Hello!");

  // 初始化NFC模块，若失败直接提示
  if (!nfc.begin()) {
    Serial.print("Didn't find PN53x board");
    while (1);
  }

  uint32_t versiondata = nfc.getFirmwareVersion();
  Serial.print("Found chip PN5"); Serial.println((versiondata>>24) & 0xFF, HEX);
  Serial.print("Firmware ver. "); Serial.print((versiondata>>16) & 0xFF, DEC);
  Serial.print('.'); Serial.println((versiondata>>8) & 0xFF, DEC);

  Serial.println("Waiting for an ISO14443A Card ...");
}

void loop(void) {
  uint8_t success;
  uint8_t uid[] = { 0, 0, 0, 0, 0, 0, 0 };
  uint8_t uidLength;

  success = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength);

  if (success) {
    Serial.println("Found an ISO14443A card");
    Serial.print("  UID Length: ");Serial.print(uidLength, DEC);Serial.println(" bytes");
    Serial.print("  UID Value: ");
    nfc.PrintHex(uid, uidLength);
    Serial.println("");

    if (uidLength == 4)
    {
      Serial.println("Seems to be a Mifare Classic card (4 byte UID)");
      uint8_t keya[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };

      success = nfc.mifareclassic_AuthenticateBlock(uid, uidLength, 4, 0, keya);

      if (success)
      {
        Serial.println("Sector 1 (Blocks 4..7) has been authenticated");
        uint8_t data[16];

        success = nfc.mifareclassic_ReadDataBlock(4, data);

        if (success)
        {
          Serial.println("Reading Block 4:");
          nfc.PrintHexChar(data, 16);
          Serial.println("");
          delay(1000);
        }
        else
        {
          Serial.println("无法读取指定区块，请尝试其他密钥？");
        }
      }
      else
      {
        Serial.println("认证失败，请尝试其他密钥？");
      }
    }

    if (uidLength == 7)
    {
      Serial.println("Seems to be a Mifare Ultralight tag (7 byte UID)");
      uint8_t data[32];
      success = nfc.mifareultralight_ReadPage (4, data);
      if (success)
      {
        nfc.PrintHexChar(data, 4);
        Serial.println("");
        delay(1000);
      }
      else
      {
        Serial.println("无法读取指定页面？");
      }
    }
  }
}

I2C模式配置方案

若使用I2C，修改代码初始化部分：

#define PN532_IRQ 2
#define PN532_RESET 4

// 初始化I2C连接
Adafruit_PN532 nfc(PN532_IRQ, PN532_RESET);

3. 模块与兼容性测试 #

• 更换PN532模块，排除模块硬件损坏的可能。
• 使用Arduino Uno等其他开发板测试模块，确认模块本身可正常工作，排除ESP32兼容性问题。

内容的提问来源于stack exchange，提问作者Moritz Ende