MF RC522是应用于13.56MHz非接触式通信中高集成度的读写卡芯片，是NXP公司针对“三表”应用推出的一款低电压、低成本、体积小的非接触式读写卡芯片，是智能仪表和便携式手持设备研发的较好选择。 MF RC522利用了先进的调制和解调概念，完全集成了在13.56MHz下所有类型的被动非接触式通信方式和协议。支持14443A兼容应答器信号。数字部分处理ISO14443A帧和错误检测。此外，还支持快速CRYPTO1加密算法，用语验证MIFARE系列产品。MFRC522支持MIFARE系列更高速的非接触式通信，双向数据传输速率高达424kbit/s。 作为13.56MHz高集成度读写卡系列芯片家族的新成员，MF RC522与MF RC500和MF RC530有不少相似之处，同时也具备许多特点和差异。它与主机间通信采用SPI模式，有利于减少连线，缩小PCB板体积，降低成本。

• 工作电流：13—26mA/直流3.3V
• 空闲电流：10-13mA/直流3.3V
• 休眠电流：<80uA
• 峰值电流：<30mA
• 工作频率：13.56MHz
• 产品物理特性：尺寸：40mm×60mm
• 环境工作温度：摄氏-20—80度
• 环境储存温度：摄氏-40—85度
• 环境相对湿度：相对湿度5%—95%
• 通讯方式：SPI（数据最大传输速率：10Mbit/s ）

• pcDuino3  x1
• RFID RC522  x1
• 公-母杜邦线  x7
• 符合上面描述的RFID标签  x1

#include "core.h"

#define uchar unsigned char
#define uint unsigned int
//data array maxium length
#define MAX_LEN 16

/////////////////////////////////////////////////////////
//set the pin
////////////////////////////////////////////////////////
#define  _CS  10
#define  _SCK  13
#define  _MOSI 11
#define  _MISO 12
#define  NRSTPD 9

//MF522 command bits
#define PCD_IDLE 0x00 //NO action; cancel current commands
#define PCD_AUTHENT 0x0E //verify password key
#define PCD_RECEIVE 0x08 //receive data
#define PCD_TRANSMIT 0x04 //send data
#define PCD_TRANSCEIVE 0x0C //send and receive data
#define PCD_RESETPHASE 0x0F //reset
#define PCD_CALCCRC 0x03 //CRC check and caculation

//Mifare_One card command bits
#define PICC_REQIDL 0x26 //Search the cards that not into sleep mode in the antenna area 
#define PICC_REQALL 0x52 //Search all the cards in the antenna area
#define PICC_ANTICOLL 0x93 //prevent conflict
#define PICC_SElECTTAG 0x93 //select card
#define PICC_AUTHENT1A 0x60 //verify A password key
#define PICC_AUTHENT1B 0x61 //verify B password key
#define PICC_READ 0x30 //read 
#define PICC_WRITE 0xA0 //write
#define PICC_DECREMENT 0xC0 //deduct value
#define PICC_INCREMENT 0xC1 //charge up value
#define PICC_RESTORE 0xC2 //Restore data into buffer
#define PICC_TRANSFER 0xB0 //Save data into buffer
#define PICC_HALT 0x50 //sleep mode

//THe mistake code that return when communicate with MF522
#define MI_OK 0
#define MI_NOTAGERR 1
#define MI_ERR 2

//------------------MFRC522 register ---------------
//Page 0:Command and Status
#define Reserved00 0x00 
#define CommandReg 0x01 
#define CommIEnReg 0x02 
#define DivlEnReg 0x03 
#define CommIrqReg 0x04 
#define DivIrqReg 0x05
#define ErrorReg 0x06  
#define Status1Reg 0x07 
#define Status2Reg 0x08 
#define FIFODataReg 0x09
#define FIFOLevelReg 0x0A
#define WaterLevelReg 0x0B
#define ControlReg 0x0C
#define BitFramingReg 0x0D
#define CollReg 0x0E
#define Reserved01 0x0F
//Page 1:Command 
#define Reserved10 0x10
#define ModeReg 0x11
#define TxModeReg 0x12
#define RxModeReg 0x13
#define TxControlReg 0x14
#define TxAutoReg 0x15
#define TxSelReg 0x16
#define RxSelReg 0x17
#define RxThresholdReg 0x18
#define DemodReg 0x19
#define Reserved11 0x1A
#define Reserved12 0x1B
#define MifareReg 0x1C
#define Reserved13 0x1D
#define Reserved14 0x1E
#define SerialSpeedReg 0x1F
//Page 2:CFG 
#define Reserved20 0x20 
#define CRCResultRegM 0x21
#define CRCResultRegL 0x22
#define Reserved21 0x23
#define ModWidthReg 0x24
#define Reserved22 0x25
#define RFCfgReg 0x26
#define GsNReg 0x27
#define CWGsPReg 0x28
#define ModGsPReg 0x29
#define TModeReg 0x2A
#define TPrescalerReg 0x2B
#define TReloadRegH 0x2C
#define TReloadRegL 0x2D
#define TCounterValueRegH 0x2E
#define TCounterValueRegL 0x2F
//Page 3:TestRegister 
#define Reserved30 0x30
#define TestSel1Reg 0x31
#define TestSel2Reg 0x32
#define TestPinEnReg 0x33
#define TestPinValueReg 0x34
#define TestBusReg 0x35
#define AutoTestReg 0x36
#define VersionReg 0x37
#define AnalogTestReg 0x38
#define TestDAC1Reg 0x39 
#define TestDAC2Reg 0x3A 
#define TestADCReg 0x3B 
#define Reserved31 0x3C 
#define Reserved32 0x3D 
#define Reserved33 0x3E 
#define Reserved34 0x3F
//-----------------------------------------------

//4 bytes Serial number of card, the 5 bytes is verfiy bytes
uchar serNum[5];

void setup() 
{ 
    pinMode(_CS,OUTPUT);
    pinMode(_SCK,OUTPUT);
    pinMode(_MOSI,OUTPUT);
    pinMode(_MISO,INPUT);
    pinMode(NRSTPD,OUTPUT); // Not Reset and Power-down
    pinMode(NRSTPD,OUTPUT); // Set digital pin 5 , Not Reset and Power-down 
    MFRC522_Init(); 
    printf("RC522 test\n");
}

void loop()
{
    uchar status;
    uchar str[MAX_LEN];
    // Search card, return card types
    status = MFRC522_Request(PICC_REQIDL, str); 
    if (status != MI_OK)
    {
        return;
    }

     //Show card type
    ShowCardType(str);
    //Prevent conflict, return the 4 bytes Serial number of the card
    status = MFRC522_Anticoll(str);

    // str[0..3]: serial number of the card
    // str[4]: XOR checksum of the SN.
    if (status == MI_OK)
    {
        printf("The card's number is: ");
        memcpy(serNum, str, 5);
        ShowCardID(serNum);
    }
    MFRC522_Halt(); //command the card into sleep mode 
    delay(200);
}

/*
 * Function：ShowCardID
 * Description：Show Card ID
 * Input parameter：ID string
 * Return：Null
 */
void ShowCardID(uchar *id)
{
    int IDlen=4;
    for(int i=0; i<IDlen; i++){
        printf("%X",(0x0F & (id[i]>>4)));
        printf("%X",(0x0F & id[i]));
    }
    printf("\n-------------------------\n");
}

/*
 * Function：ShowCardType
 * Description：Show Card type
 * Input parameter：Type string
 * Return：Null
 */
void ShowCardType(uchar* type)
{
    printf("Card type: ");
    if(type[0]==0x04&&type[1]==0x00) 
        printf("MFOne-S50\n");
    else if(type[0]==0x02&&type[1]==0x00)
        printf("MFOne-S70\n");
    else if(type[0]==0x44&&type[1]==0x00)
        printf("MF-UltraLight\n");
    else if(type[0]==0x08&&type[1]==0x00)
        printf("MF-Pro\n");
    else if(type[0]==0x44&&type[1]==0x03)
        printf("MF Desire\n");
    else
        printf("Unknown\n");
}

/*
 * SPI read byte and write byte
 */
uchar SPIReadByte(void) 
{ 
  uchar SPICount;                   // Counter used to clock out the data 
  uchar SPIData;                   
  SPIData = 0; 
  for (SPICount = 0; SPICount < 8; SPICount++)  // Prepare to clock in the data to be read 
  { 
    SPIData <<=1;                               // Rotate the data 
    digitalWrite(_SCK,LOW);// Raise the clock to clock the data out of the MAX7456 
   if(digitalRead(_MISO)) 
   { 
     SPIData|=0x01; 
   } 
    digitalWrite(_SCK,HIGH); // Drop the clock ready for the next bit 
  }                                                             // and loop back 
  return (SPIData);                             // Finally return the read data 
}  
void SPIWriteByte(uchar SPIData) 
{ 
  uchar SPICount;                 // Counter used to clock out the data 
  for (SPICount = 0; SPICount < 8; SPICount++) 
  { 
    if (SPIData & 0x80) 
    { 
      digitalWrite(_MOSI,HIGH);
    } 
    else 
    { 
      digitalWrite(_MOSI,LOW);
    } 
    digitalWrite(_SCK,LOW); 
    SPIData <<= 1; 
    digitalWrite(_SCK,HIGH); 
  }           
}

/*
 * Function：Write_MFRC5200
 * Description：write a byte data into one register of MR RC522
 * Input parameter：addr--register address；val--the value that need to write in
 * Return：Null
 */
void Write_MFRC522(uchar addr, uchar val)
{
    digitalWrite(_CS, LOW);
    SPIWriteByte((addr<<1)&0x7E);
    SPIWriteByte(val);
    digitalWrite(_CS, HIGH);
}

/*
 * Function：Read_MFRC522
 * Description：read a byte data into one register of MR RC522
 * Input parameter：addr--register address
 * Return：return the read value
 */
uchar Read_MFRC522(uchar addr)
{
    uchar val;
    digitalWrite(_CS, LOW);
    SPIWriteByte(((addr<<1)&0x7E)|0x80);
    val = SPIReadByte();
    digitalWrite(_CS, HIGH);
    return val; 
}

/*
 * Function：SetBitMask
 * Description：set RC522 register bit
 * Input parameter：reg--register address;mask--value
 * Return：null
 */
void SetBitMask(uchar reg, uchar mask) 
{
    uchar tmp;
    tmp = Read_MFRC522(reg);
    Write_MFRC522(reg, tmp | mask); // set bit mask
}

/*
 * Function：ClearBitMask
 * Description：clear RC522 register bit
 * Input parameter：reg--register address;mask--value
 * Return：null
 */
void ClearBitMask(uchar reg, uchar mask) 
{
    uchar tmp;
    tmp = Read_MFRC522(reg);
    Write_MFRC522(reg, tmp & (~mask)); // clear bit mask
} 

/*
 * Function：AntennaOn
 * Description：Turn on antenna, every time turn on or shut down antenna need at least 1ms delay
 * Input parameter：null
 * Return：null
 */
void AntennaOn(void)
{
    uchar temp;

    temp = Read_MFRC522(TxControlReg);
    if (!(temp & 0x03))
    {
        SetBitMask(TxControlReg, 0x03);
    }
}

/*
 * Function：AntennaOff
 * Description：Turn off antenna, every time turn on or shut down antenna need at least 1ms delay
 * Input parameter：null
 * Return：null
 */
void AntennaOff(void)
{
    ClearBitMask(TxControlReg, 0x03);
}

/*
 * Function：ResetMFRC522
 * Description： reset RC522
 * Input parameter：null
 * Return：null
 */
void MFRC522_Reset(void)
{
    Write_MFRC522(CommandReg, PCD_RESETPHASE);
}

/*
 * Function：InitMFRC522
 * Description：initilize RC522
 * Input parameter：null
 * Return：null
 */
void MFRC522_Init(void)
{
    digitalWrite(NRSTPD,HIGH);

    MFRC522_Reset();

    //Timer: TPrescaler*TreloadVal/6.78MHz = 24ms
    Write_MFRC522(TModeReg, 0x8D); //Tauto=1; f(Timer) = 6.78MHz/TPreScaler
    Write_MFRC522(TPrescalerReg, 0x3E); //TModeReg[3..0] + TPrescalerReg
    Write_MFRC522(TReloadRegL, 30); 
    Write_MFRC522(TReloadRegH, 0);

    Write_MFRC522(TxAutoReg, 0x40); //100%ASK
    Write_MFRC522(ModeReg, 0x3D); //CRC initilizate value 0x6363 ???

    //ClearBitMask(Status2Reg, 0x08); //MFCrypto1On=0
    //Write_MFRC522(RxSelReg, 0x86); //RxWait = RxSelReg[5..0]
    //Write_MFRC522(RFCfgReg, 0x7F); //RxGain = 48dB

    AntennaOn(); //turn on antenna
}

/*
 * Function：MFRC522_Request
 * Description：Searching card, read card type
 * Input parameter：reqMode--search methods，
 * TagType--return card types
 * 0x4400 = Mifare_UltraLight
 * 0x0400 = Mifare_One(S50)
 * 0x0200 = Mifare_One(S70)
 * 0x0800 = Mifare_Pro(X)
 * 0x4403 = Mifare_DESFire
 * return：return MI_OK if successed
 */
uchar MFRC522_Request(uchar reqMode, uchar *TagType)
{
    uchar status; 
    uint backBits; //the data bits that received

    Write_MFRC522(BitFramingReg, 0x07); //TxLastBists = BitFramingReg[2..0] ???

    TagType[0] = reqMode;
    status = MFRC522_ToCard(PCD_TRANSCEIVE, TagType, 1, TagType, &backBits);

    if ((status != MI_OK) || (backBits != 0x10))
    { 
        status = MI_ERR;
    }

    return status;
}

/*
 * Function：MFRC522_ToCard
 * Description：communicate between RC522 and ISO14443
 * Input parameter：command--MF522 command bits
 * sendData--send data to card via rc522
 * sendLen--send data length 
 * backData--the return data from card
 * backLen--the length of return data
 * return：return MI_OK if successed
 */
uchar MFRC522_ToCard(uchar command, uchar *sendData, uchar sendLen, uchar *backData, uint *backLen)
{
    uchar status = MI_ERR;
    uchar irqEn = 0x00;
    uchar waitIRq = 0x00;
    uchar lastBits;
    uchar n;
    uint i;

    switch (command)
    {
        case PCD_AUTHENT: //verify card password
        {
            irqEn = 0x12;
            waitIRq = 0x10;
            break;
        }
        case PCD_TRANSCEIVE: //send data in the FIFO
        {
            irqEn = 0x77;
            waitIRq = 0x30;
            break;
        }
        default:
            break;
    }

    Write_MFRC522(CommIEnReg, irqEn|0x80); //Allow interruption
    ClearBitMask(CommIrqReg, 0x80); //Clear all the interrupt bits
    SetBitMask(FIFOLevelReg, 0x80); //FlushBuffer=1, FIFO initilizate

    Write_MFRC522(CommandReg, PCD_IDLE); //NO action;cancel current command ???

    //write data into FIFO
    for (i=0; i<sendLen; i++)
    { 
        Write_MFRC522(FIFODataReg, sendData[i]); 
    }

    //procceed it
    Write_MFRC522(CommandReg, command);
    if (command == PCD_TRANSCEIVE)
    { 
        SetBitMask(BitFramingReg, 0x80); //StartSend=1,transmission of data starts 
    } 

    //waite receive data is finished
    i = 2000; //i should adjust according the clock, the maxium the waiting time should be 25 ms???
    do 
    {
        //CommIrqReg[7..0]
        //Set1 TxIRq RxIRq IdleIRq HiAlerIRq LoAlertIRq ErrIRq TimerIRq
        n = Read_MFRC522(CommIrqReg);
        i--;
    }
    while ((i!=0) && !(n&0x01) && !(n&waitIRq));

    ClearBitMask(BitFramingReg, 0x80); //StartSend=0

    if (i != 0)
    { 
        if(!(Read_MFRC522(ErrorReg) & 0x1B)) //BufferOvfl Collerr CRCErr ProtecolErr
        {
            status = MI_OK;
            if (n & irqEn & 0x01)
            { 
                status = MI_NOTAGERR; //?? 
            }

            if (command == PCD_TRANSCEIVE)
            {
                n = Read_MFRC522(FIFOLevelReg);
                lastBits = Read_MFRC522(ControlReg) & 0x07;
                if (lastBits)
                { 
                    *backLen = (n-1)*8 + lastBits; 
                }
                else
                { 
                    *backLen = n*8; 
                }

                if (n == 0)
                { 
                    n = 1; 
                }
                if (n > MAX_LEN)
                { 
                    n = MAX_LEN; 
                }

                //read the data from FIFO
                for (i=0; i<n; i++)
                { 
                    backData[i] = Read_MFRC522(FIFODataReg); 
                }
            }
        }
        else
        { 
            status = MI_ERR; 
        }

    }

    //SetBitMask(ControlReg,0x80); //timer stops
    //Write_MFRC522(CommandReg, PCD_IDLE); 

    return status;
}

/*
 * Function：MFRC522_Anticoll
 * Description：Prevent conflict, read the card serial number 
 * Input parameter：serNum--return the 4 bytes card serial number, the 5th byte is recheck byte
 * return：return MI_OK if successed
 */
uchar MFRC522_Anticoll(uchar *serNum)
{
    uchar status;
    uchar i;
    uchar serNumCheck=0;
    uint unLen;

    //ClearBitMask(Status2Reg, 0x08); //strSensclear
    //ClearBitMask(CollReg,0x80); //ValuesAfterColl
    Write_MFRC522(BitFramingReg, 0x00); //TxLastBists = BitFramingReg[2..0]

    serNum[0] = PICC_ANTICOLL;
    serNum[1] = 0x20;
    status = MFRC522_ToCard(PCD_TRANSCEIVE, serNum, 2, serNum, &unLen);

    if (status == MI_OK)
    {
        //Verify card serial number
        for (i=0; i<4; i++)
        { 
            serNumCheck ^= serNum[i];
        }
        if (serNumCheck != serNum[i])
        { 
            status = MI_ERR; 
        }
    }

    //SetBitMask(CollReg, 0x80); //ValuesAfterColl=1

    return status;
} 

/*
 * Function：CalulateCRC
 * Description：Use MF522 to caculate CRC
 * Input parameter：pIndata--the CRC data need to be read，len--data length，pOutData-- the caculated result of CRC
 * return：Null
 */
void CalulateCRC(uchar *pIndata, uchar len, uchar *pOutData)
{
    uchar i, n;

    ClearBitMask(DivIrqReg, 0x04); //CRCIrq = 0
    SetBitMask(FIFOLevelReg, 0x80); //Clear FIFO pointer
    //Write_MFRC522(CommandReg, PCD_IDLE);

    //Write data into FIFO 
    for (i=0; i<len; i++)
    { 
        Write_MFRC522(FIFODataReg, *(pIndata+i)); 
    }
    Write_MFRC522(CommandReg, PCD_CALCCRC);

    //waite CRC caculation to finish
    i = 0xFF;
    do 
    {
        n = Read_MFRC522(DivIrqReg);
        i--;
    }
    while ((i!=0) && !(n&0x04)); //CRCIrq = 1

    //read CRC caculation result
    pOutData[0] = Read_MFRC522(CRCResultRegL);
    pOutData[1] = Read_MFRC522(CRCResultRegM);
}

/*
 * Function：MFRC522_Write
 * Description：write block data
 * Input parameters：blockAddr--block address;writeData--Write 16 bytes data into block
 * return：return MI_OK if successed
 */
uchar MFRC522_Write(uchar blockAddr, uchar *writeData)
{
    uchar status;
    uint recvBits;
    uchar i;
    uchar buff[18]; 

    buff[0] = PICC_WRITE;
    buff[1] = blockAddr;
    CalulateCRC(buff, 2, &buff[2]);
    status = MFRC522_ToCard(PCD_TRANSCEIVE, buff, 4, buff, &recvBits);

    if ((status != MI_OK) || (recvBits != 4) || ((buff[0] & 0x0F) != 0x0A))
    { 
        status = MI_ERR; 
    }

    if (status == MI_OK)
    {
        for (i=0; i<16; i++) //Write 16 bytes data into FIFO
        { 
            buff[i] = *(writeData+i); 
        }
        CalulateCRC(buff, 16, &buff[16]);
        status = MFRC522_ToCard(PCD_TRANSCEIVE, buff, 18, buff, &recvBits);

        if ((status != MI_OK) || (recvBits != 4) || ((buff[0] & 0x0F) != 0x0A))
        { 
            status = MI_ERR; 
        }
    }

    return status;
}

/*
 * Function：MFRC522_Halt
 * Description：Command the cards into sleep mode
 * Input parameters：null
 * return：null
 */
void MFRC522_Halt(void)
{
    uchar status;
    uint unLen;
    uchar buff[4]; 

    buff[0] = PICC_HALT;
    buff[1] = 0;
    CalulateCRC(buff, 2, &buff[2]);

    status = MFRC522_ToCard(PCD_TRANSCEIVE, buff, 4, buff,&unLen);
}

1、硬件接线：

RC522 SDA  –> pcDuino D10

RC522 SCK  –> pcDuino D13

RC522 MOSI  –> pcDuino D11

RC522 MISO  –> pcDuino D12

RC522 RST  –> pcDuino D9

RC522 3.3V  –> pcDuino 3.3V

RC522 GND  –> pcDuino GND

2、下载测试代码，在ArduinoIDE中运行代码：

3、运行代码,将标签放置在RC522模块的感应区域内，即可读到卡的信息：