mfrc522_drv.cpp

/*
* MFRC522.cpp - Library to use ARDUINO RFID MODULE KIT 13.56 MHZ WITH TAGS SPI W AND R BY COOQROBOT.
* NOTE: Please also check the comments in MFRC522.h - they provide useful hints and background information.
* Released into the public domain.
*/
 
#include <cstring> // for memcpy
#include <cstdio>
#include "mfrc522_drv.h"
#include "spi_interface.h"
#include "gpio_interface.h"
#include "task.h"
 
#ifndef MFRC522_SPICLOCK
#define MFRC522_SPICLOCK (4000000u)    // MFRC522 accept upto 10MHz, set to 4MHz.
#endif
 
// Functions for setting up the Arduino
 
mfrc522_drv::mfrc522_drv(spi_interface & spi, gpio_interface & reset)
: _spi(spi), _reset(reset) {
    _reset.gpioMode(GPIO::OUTPUT | GPIO::INIT_HIGH);
    _spi.setSpeed(MFRC522_SPICLOCK);
    _spi.generateCS(false);
    _spi.setCS(HIGH);
}
 
// Basic interface functions for communicating with the MFRC522
 
void mfrc522_drv::PCD_WriteRegister(PCD_Register reg, uint8_t value) {
    uint8_t buf[2];
    buf[0] = reg;
    buf[1] = value;
 
    _spi.setCS(LOW);
    _spi.spiTx(buf, 2);
    _spi.setCS(HIGH);
}
 
void mfrc522_drv::PCD_WriteRegister(PCD_Register reg,   
                                uint8_t  count,     
                                uint8_t *values) {  
    uint8_t buf[4096];
    buf[0] = reg;
    for(size_t i=0; i < count; ++i) buf[i+1] = values[i];
 
    _spi.setCS(LOW);
    _spi.spiTx(buf, count+1);
    _spi.setCS(HIGH);
}
 
uint8_t mfrc522_drv::PCD_ReadRegister(PCD_Register reg) {
    uint8_t buf_tx[1];
    uint8_t buf_rx[1];
    buf_tx[0] = 0x80 | reg;
 
    _spi.setCS(LOW);
    _spi.spiTx(buf_tx, 1);
    _spi.spiRx(0, buf_rx, 1);
    _spi.setCS(HIGH);
 
    return buf_rx[0];
}
 
void mfrc522_drv::PCD_ReadRegister(PCD_Register reg,    
                               uint8_t count,       
                               uint8_t *values,     
                               uint8_t rxAlign) {   
    uint8_t buf_rx[1];
    if (count == 0) return;
 
    uint8_t address = 0x80 | reg;           // MSB == 1 is for reading. LSB is not used in address. Datasheet section 8.1.2.3.
    uint8_t index   = 0;                    // Index in values array.
 
    _spi.setCS(LOW);
    count--;                                // One read is performed outside of the loop
    _spi.spiTx(&address, 1);                // Tell MFRC522 which address we want to read
    if (rxAlign) {                          // Only update bit positions rxAlign..7 in values[0]
        // Create bit mask for bit positions rxAlign..7
        uint8_t mask = (0xFF << rxAlign) & 0xFF;
        // Read value and tell that we want to read the same address again.
        _spi.spiRx(address, buf_rx, 1);
        uint8_t value = buf_rx[0];
        // Apply mask to both current value of values[0] and the new data in value.
        values[0] = (values[0] & ~mask) | (value & mask);
        index++;
    }
    while (index < count) {
        _spi.spiRx(address, buf_rx, 1);     // Read value and tell that we want to read the same address again.
        values[index] = buf_rx[0];
        index++;
    }
    _spi.spiRx(0, buf_rx, 1);               // Read value and tell that we want to read the same address again.
    values[index] = buf_rx[0];
    _spi.setCS(HIGH);
 
}
 
void mfrc522_drv::PCD_SetRegisterBitMask(PCD_Register reg,    
                                     uint8_t mask            
) {
    uint8_t tmp;
    tmp = PCD_ReadRegister(reg);
    PCD_WriteRegister(reg, tmp | mask);            // set bit mask
} // End PCD_SetRegisterBitMask()
 
void mfrc522_drv::PCD_ClearRegisterBitMask(PCD_Register reg,    
                                       uint8_t mask) {      
    uint8_t tmp;
    tmp = PCD_ReadRegister(reg);
    PCD_WriteRegister(reg, tmp & (~mask));        // clear bit mask
}
 
 
mfrc522_drv::StatusCode mfrc522_drv::PCD_CalculateCRC(
        uint8_t *data,        
        uint8_t length,    
        uint8_t *result    
) {
    PCD_WriteRegister(CommandReg, PCD_Idle);        // Stop any active command.
    PCD_WriteRegister(DivIrqReg, 0x04);                // Clear the CRCIRq interrupt request bit
    PCD_WriteRegister(FIFOLevelReg, 0x80);            // FlushBuffer = 1, FIFO initialization
    PCD_WriteRegister(FIFODataReg, length, data);    // Write data to the FIFO
    PCD_WriteRegister(CommandReg, PCD_CalcCRC);        // Start the calculation
 
    // Wait for the CRC calculation to complete. Check for the register to
    // indicate that the CRC calculation is complete in a loop. If the
    // calculation is not indicated as complete in ~90ms, then time out
    // the operation.
    const uint32_t deadline = task::millis() + 89;
 
    do {
        // DivIrqReg[7..0] bits are: Set2 reserved reserved MfinActIRq reserved CRCIRq reserved reserved
        uint8_t n = PCD_ReadRegister(DivIrqReg);
        if (n & 0x04) {                                    // CRCIRq bit set - calculation done
            PCD_WriteRegister(CommandReg, PCD_Idle);    // Stop calculating CRC for new content in the FIFO.
            // Transfer the result from the registers to the result buffer
            result[0] = PCD_ReadRegister(CRCResultRegL);
            result[1] = PCD_ReadRegister(CRCResultRegH);
            return STATUS_OK;
        }
        task::yield();
    } while (static_cast<uint32_t> (task::millis()) < deadline);
 
    // 89ms passed and nothing happened. Communication with the MFRC522 might be down.
    return STATUS_TIMEOUT;
}
 
 
// Functions for manipulating the MFRC522
 
void mfrc522_drv::PCD_Init() {
    bool hardReset = false;
 
    // First set the resetPowerDownPin as digital input, to check the MFRC522 power down mode.
    _reset.gpioMode(GPIO::INPUT);
 
    if (_reset.gpioRead() == LOW) {    // The MFRC522 chip is in power down mode.
        _reset.gpioMode(GPIO::OUTPUT); // Now set the resetPowerDownPin as digital output.
        _reset.gpioWrite(LOW);         // Make sure we have a clean LOW state.
        task::sleep_ms(5);
        _reset.gpioWrite(HIGH);        // Exit power down mode. This triggers a hard reset.
        // Section 8.8.2 in the datasheet says the oscillator start-up time is the start up time of the crystal + 37,74μs. Let us be generous: 50ms.
        task::sleep_ms(50);
        hardReset = true;
    }
 
    if (!hardReset) { // Perform a soft reset if we haven't triggered a hard reset above.
        PCD_Reset();
    }
 
    // Reset baud rates
    PCD_WriteRegister(TxModeReg, 0x00);
    PCD_WriteRegister(RxModeReg, 0x00);
    // Reset ModWidthReg
    PCD_WriteRegister(ModWidthReg, 0x26);
 
    // When communicating with a PICC we need a timeout if something goes wrong.
    // f_timer = 13.56 MHz / (2*TPreScaler+1) where TPreScaler = [TPrescaler_Hi:TPrescaler_Lo].
    // TPrescaler_Hi are the four low bits in TModeReg. TPrescaler_Lo is TPrescalerReg.
    PCD_WriteRegister(TModeReg,      0x80);     // TAuto=1; timer starts automatically at the end of the transmission in all communication modes at all speeds
    PCD_WriteRegister(TPrescalerReg, 0xA9);     // TPreScaler = TModeReg[3..0]:TPrescalerReg, ie 0x0A9 = 169 => f_timer=40kHz, ie a timer period of 25μs.
    PCD_WriteRegister(TReloadRegH,   0x03);     // Reload timer with 0x3E8 = 1000, ie 25ms before timeout.
    PCD_WriteRegister(TReloadRegL,   0xE8);
 
    PCD_WriteRegister(TxASKReg,      0x40);     // Default 0x00. Force a 100 % ASK modulation independent of the ModGsPReg register setting
    PCD_WriteRegister(ModeReg,       0x3D);     // Default 0x3F. Set the preset value for the CRC coprocessor for the CalcCRC command to 0x6363 (ISO 14443-3 part 6.2.4)
    PCD_AntennaOn();                            // Enable the antenna driver pins TX1 and TX2 (they were disabled by the reset)
}
 
void mfrc522_drv::PCD_Reset() {
    PCD_WriteRegister(CommandReg, PCD_SoftReset);    // Issue the SoftReset command.
    // The datasheet does not mention how long the SoftRest command takes to complete.
    // But the MFRC522 might have been in soft power-down mode (triggered by bit 4 of CommandReg)
    // Section 8.8.2 in the datasheet says the oscillator start-up time is the start up time of the crystal + 37,74μs. Let us be generous: 50ms.
    uint8_t count = 0;
    do {
        // Wait for the PowerDown bit in CommandReg to be cleared (max 3x50ms)
        task::sleep_ms(50);
    } while ((PCD_ReadRegister(CommandReg) & (1 << 4)) && (++count) < 3);
}
 
void mfrc522_drv::PCD_AntennaOn() {
    uint8_t value = PCD_ReadRegister(TxControlReg);
    if ((value & 0x03) != 0x03) {
        PCD_WriteRegister(TxControlReg, value | 0x03);
    }
}
 
void mfrc522_drv::PCD_AntennaOff() {
    PCD_ClearRegisterBitMask(TxControlReg, 0x03);
}
 
uint8_t mfrc522_drv::PCD_GetAntennaGain() {
    return PCD_ReadRegister(RFCfgReg) & (0x07 << 4);
}
 
void mfrc522_drv::PCD_SetAntennaGain(uint8_t mask) {
    if (PCD_GetAntennaGain() != mask) {                        // only bother if there is a change
        PCD_ClearRegisterBitMask(RFCfgReg, (0x07 << 4));        // clear needed to allow 000 pattern
        PCD_SetRegisterBitMask(RFCfgReg, mask & (0x07 << 4));    // only set RxGain[2:0] bits
    }
}
 
bool mfrc522_drv::PCD_PerformSelfTest() {
    // This follows directly the steps outlined in 16.1.1
    // 1. Perform a soft reset.
    PCD_Reset();
 
    // 2. Clear the internal buffer by writing 25 uint8_ts of 00h
    uint8_t ZEROES[25] = {0x00};
    PCD_WriteRegister(FIFOLevelReg, 0x80);        // flush the FIFO buffer
    PCD_WriteRegister(FIFODataReg, 25, ZEROES);    // write 25 uint8_ts of 00h to FIFO
    PCD_WriteRegister(CommandReg, PCD_Mem);        // transfer to internal buffer
 
    // 3. Enable self-test
    PCD_WriteRegister(AutoTestReg, 0x09);
 
    // 4. Write 00h to FIFO buffer
    PCD_WriteRegister(FIFODataReg, 0x00);
 
    // 5. Start self-test by issuing the CalcCRC command
    PCD_WriteRegister(CommandReg, PCD_CalcCRC);
 
    // 6. Wait for self-test to complete
    uint8_t n;
    for (uint8_t i = 0; i < 0xFF; i++) {
        // The datasheet does not specify exact completion condition except
        // that FIFO buffer should contain 64 uint8_ts.
        // While selftest is initiated by CalcCRC command
        // it behaves differently from normal CRC computation,
        // so one can't reliably use DivIrqReg to check for completion.
        // It is reported that some devices does not trigger CRCIRq flag
        // during selftest.
        n = PCD_ReadRegister(FIFOLevelReg);
        if (n >= 64) {
            break;
        }
    }
    PCD_WriteRegister(CommandReg, PCD_Idle);        // Stop calculating CRC for new content in the FIFO.
 
    // 7. Read out resulting 64 uint8_ts from the FIFO buffer.
    uint8_t result[64];
    PCD_ReadRegister(FIFODataReg, 64, result, 0);
 
    // Auto self-test done
    // Reset AutoTestReg register to be 0 again. Required for normal operation.
    PCD_WriteRegister(AutoTestReg, 0x00);
 
    // Determine firmware version (see section 9.3.4.8 in spec)
    uint8_t version = PCD_ReadRegister(VersionReg);
 
    // Pick the appropriate reference values
    const uint8_t *reference;
    switch (version) {
        case 0x88:    // Fudan Semiconductor FM17522 clone
            reference = FM17522_firmware_reference;
            break;
        case 0x90:    // Version 0.0
            reference = MFRC522_firmware_referenceV0_0;
            break;
        case 0x91:    // Version 1.0
            reference = MFRC522_firmware_referenceV1_0;
            break;
        case 0x92:    // Version 2.0
            reference = MFRC522_firmware_referenceV2_0;
            break;
        default:    // Unknown version
            return false; // abort test
    }
 
    // Verify that the results match up to our expectations
    for (uint8_t i = 0; i < 64; i++) {
        if (result[i] != reference[i]) {
            return false;
        }
    }
 
    // 8. Perform a re-init, because PCD does not work after test.
    // Reset does not work as expected.
    // "Auto self-test done" does not work as expected.
    PCD_Init();
 
    // Test passed; all is good.
    return true;
}
 
// Power control
 
//IMPORTANT NOTE!!!!
//Calling any other function that uses CommandReg will disable soft power down mode !!!
//For more details about power control, refer to the datasheet - page 33 (8.6)
 
void mfrc522_drv::PCD_SoftPowerDown() {//Note : Only soft power down mode is available throught software
    uint8_t val = PCD_ReadRegister(CommandReg); // Read state of the command register
    val |= (1 << 4);// set PowerDown bit ( bit 4 ) to 1
    PCD_WriteRegister(CommandReg, val);//write new value to the command register
}
 
void mfrc522_drv::PCD_SoftPowerUp() {
    uint8_t val = PCD_ReadRegister(CommandReg); // Read state of the command register
    val &= ~(1 << 4);// set PowerDown bit ( bit 4 ) to 0
    PCD_WriteRegister(CommandReg, val);//write new value to the command register
    // wait until PowerDown bit is cleared (this indicates end of wake up procedure)
    const uint32_t timeout = (uint32_t) task::millis() + 500;// create timer for timeout (just in case)
 
    while (task::millis() <= timeout) { // set timeout to 500 ms
        val = PCD_ReadRegister(CommandReg);// Read state of the command register
        if (!(val & (1 << 4))) { // if powerdown bit is 0
            break;// wake up procedure is finished
        }
        task::yield();
    }
}
 
// Functions for communicating with PICCs
 
mfrc522_drv::StatusCode
mfrc522_drv::PCD_TransceiveData(uint8_t *sendData,        
                            uint8_t sendLen,        
                            uint8_t *backData,        
                            uint8_t *backLen,        
                            uint8_t *validBits,    
                            uint8_t rxAlign,        
                            bool checkCRC        
) {
    uint8_t waitIRq = 0x30;        // RxIRq and IdleIRq
    return PCD_CommunicateWithPICC(PCD_Transceive, waitIRq, sendData, sendLen, backData, backLen, validBits, rxAlign,
                                   checkCRC);
} // End PCD_TransceiveData()
 
mfrc522_drv::StatusCode
mfrc522_drv::PCD_CommunicateWithPICC(uint8_t command,        
                                 uint8_t waitIRq,        
                                 uint8_t *sendData,        
                                 uint8_t sendLen,        
                                 uint8_t *backData,        
                                 uint8_t *backLen,        
                                 uint8_t *validBits,    
                                 uint8_t rxAlign,        
                                 bool checkCRC        
) {
    // Prepare values for BitFramingReg
    uint8_t txLastBits = validBits ? *validBits : 0;
    uint8_t bitFraming =
            (rxAlign << 4) + txLastBits;        // RxAlign = BitFramingReg[6..4]. TxLastBits = BitFramingReg[2..0]
 
    PCD_WriteRegister(CommandReg, PCD_Idle);            // Stop any active command.
    PCD_WriteRegister(ComIrqReg, 0x7F);                    // Clear all seven interrupt request bits
    PCD_WriteRegister(FIFOLevelReg, 0x80);                // FlushBuffer = 1, FIFO initialization
    PCD_WriteRegister(FIFODataReg, sendLen, sendData);    // Write sendData to the FIFO
    PCD_WriteRegister(BitFramingReg, bitFraming);        // Bit adjustments
    PCD_WriteRegister(CommandReg, command);                // Execute the command
    if (command == PCD_Transceive) {
        PCD_SetRegisterBitMask(BitFramingReg, 0x80);    // StartSend=1, transmission of data starts
    }
 
    // In PCD_Init() we set the TAuto flag in TModeReg. This means the timer
    // automatically starts when the PCD stops transmitting.
    //
    // Wait here for the command to complete. The bits specified in the
    // `waitIRq` parameter define what bits constitute a completed command.
    // When they are set in the ComIrqReg register, then the command is
    // considered complete. If the command is not indicated as complete in
    // ~36ms, then consider the command as timed out.
    const uint32_t deadline = task::millis() + 36;
    bool completed = false;
 
    do {
        uint8_t n = PCD_ReadRegister(
                ComIrqReg);    // ComIrqReg[7..0] bits are: Set1 TxIRq RxIRq IdleIRq HiAlertIRq LoAlertIRq ErrIRq TimerIRq
        if (n & waitIRq) {                    // One of the interrupts that signal success has been set.
            completed = true;
            break;
        }
        if (n & 0x01) {                        // Timer interrupt - nothing received in 25ms
            return STATUS_TIMEOUT;
        }
        task::yield();
    } while (static_cast<uint32_t> (task::millis()) < deadline);
 
    // 36ms and nothing happened. Communication with the MFRC522 might be down.
    if (!completed) {
        return STATUS_TIMEOUT;
    }
 
    // Stop now if any errors except collisions were detected.
    uint8_t errorRegValue = PCD_ReadRegister(
            ErrorReg); // ErrorReg[7..0] bits are: WrErr TempErr reserved BufferOvfl CollErr CRCErr ParityErr ProtocolErr
    if (errorRegValue & 0x13) {     // BufferOvfl ParityErr ProtocolErr
        return STATUS_ERROR;
    }
 
    uint8_t _validBits = 0;
 
    // If the caller wants data back, get it from the MFRC522.
    if (backData && backLen) {
        uint8_t n = PCD_ReadRegister(FIFOLevelReg);    // Number of uint8_ts in the FIFO
        if (n > *backLen) {
            return STATUS_NO_ROOM;
        }
        *backLen = n;                                            // Number of uint8_ts returned
        PCD_ReadRegister(FIFODataReg, n, backData, rxAlign);    // Get received data from FIFO
        _validBits = PCD_ReadRegister(ControlReg) &
                     0x07;        // RxLastBits[2:0] indicates the number of valid bits in the last received uint8_t. If this value is 000b, the whole uint8_t is valid.
        if (validBits) {
            *validBits = _validBits;
        }
    }
 
    // Tell about collisions
    if (errorRegValue & 0x08) {        // CollErr
        return STATUS_COLLISION;
    }
 
    // Perform CRC_A validation if requested.
    if (backData && backLen && checkCRC) {
        // In this case a MIFARE Classic NAK is not OK.
        if (*backLen == 1 && _validBits == 4) {
            return STATUS_MIFARE_NACK;
        }
        // We need at least the CRC_A value and all 8 bits of the last uint8_t must be received.
        if (*backLen < 2 || _validBits != 0) {
            return STATUS_CRC_WRONG;
        }
        // Verify CRC_A - do our own calculation and store the control in controlBuffer.
        uint8_t controlBuffer[2];
        mfrc522_drv::StatusCode status = PCD_CalculateCRC(&backData[0], *backLen - 2, &controlBuffer[0]);
        if (status != STATUS_OK) {
            return status;
        }
        if ((backData[*backLen - 2] != controlBuffer[0]) || (backData[*backLen - 1] != controlBuffer[1])) {
            return STATUS_CRC_WRONG;
        }
    }
 
    return STATUS_OK;
} // End PCD_CommunicateWithPICC()
 
mfrc522_drv::StatusCode
mfrc522_drv::PICC_RequestA(uint8_t *bufferATQA,    
                       uint8_t *bufferSize    
) {
    return PICC_REQA_or_WUPA(PICC_CMD_REQA, bufferATQA, bufferSize);
} // End PICC_RequestA()
 
mfrc522_drv::StatusCode
mfrc522_drv::PICC_WakeupA(uint8_t *bufferATQA,    
                      uint8_t *bufferSize    
) {
    return PICC_REQA_or_WUPA(PICC_CMD_WUPA, bufferATQA, bufferSize);
} // End PICC_WakeupA()
 
mfrc522_drv::StatusCode
mfrc522_drv::PICC_REQA_or_WUPA(uint8_t command,        
                           uint8_t *bufferATQA,    
                           uint8_t *bufferSize    
) {
    uint8_t validBits;
    mfrc522_drv::StatusCode status;
 
    if (bufferATQA == nullptr || *bufferSize < 2) {    // The ATQA response is 2 uint8_ts long.
        return STATUS_NO_ROOM;
    }
    PCD_ClearRegisterBitMask(CollReg, 0x80);        // ValuesAfterColl=1 => Bits received after collision are cleared.
    validBits = 7;                                    // For REQA and WUPA we need the short frame format - transmit only 7 bits of the last (and only) uint8_t. TxLastBits = BitFramingReg[2..0]
    status = PCD_TransceiveData(&command, 1, bufferATQA, bufferSize, &validBits);
    if (status != STATUS_OK) {
        return status;
    }
    if (*bufferSize != 2 || validBits != 0) {        // ATQA must be exactly 16 bits.
        return STATUS_ERROR;
    }
    return STATUS_OK;
} // End PICC_REQA_or_WUPA()
 
mfrc522_drv::StatusCode mfrc522_drv::PICC_Select(
        Uid *uid,            
        uint8_t validBits        
) {
    bool uidComplete;
    bool selectDone;
    bool useCascadeTag;
    uint8_t cascadeLevel = 1;
    mfrc522_drv::StatusCode result;
    uint8_t count;
    uint8_t checkBit;
    uint8_t index;
    uint8_t uidIndex;                    // The first index in uid->uidByte[] that is used in the current Cascade Level.
    int8_t currentLevelKnownBits;        // The number of known UID bits in the current Cascade Level.
    uint8_t buffer[9];                    // The SELECT/ANTICOLLISION commands uses a 7 uint8_t standard frame + 2 uint8_ts CRC_A
    uint8_t bufferUsed;                // The number of uint8_ts used in the buffer, ie the number of uint8_ts to transfer to the FIFO.
    uint8_t rxAlign;                    // Used in BitFramingReg. Defines the bit position for the first bit received.
    uint8_t txLastBits;                // Used in BitFramingReg. The number of valid bits in the last transmitted uint8_t.
    uint8_t *responseBuffer;
    uint8_t responseLength;
 
    // Description of buffer structure:
    //      Byte 0: SEL                 Indicates the Cascade Level: PICC_CMD_SEL_CL1, PICC_CMD_SEL_CL2 or PICC_CMD_SEL_CL3
    //      Byte 1: NVB                 Number of Valid Bits (in complete command, not just the UID): High nibble: complete uint8_ts, Low nibble: Extra bits.
    //      Byte 2: UID-data or CT      See explanation below. CT means Cascade Tag.
    //      Byte 3: UID-data
    //      Byte 4: UID-data
    //      Byte 5: UID-data
    //      Byte 6: BCC                 Block Check Character - XOR of uint8_ts 2-5
    //      Byte 7: CRC_A
    //      Byte 8: CRC_A
    // The BCC and CRC_A are only transmitted if we know all the UID bits of the current Cascade Level.
    //
    // Description of uint8_ts 2-5: (Section 6.5.4 of the ISO/IEC 14443-3 draft: UID contents and cascade levels)
    //      UID size    Cascade level   Byte2   Byte3   Byte4   Byte5
    //      ========    =============   =====   =====   =====   =====
    //       4 uint8_ts     1           uid0    uid1    uid2    uid3
    //       7 uint8_ts     1           CT      uid0    uid1    uid2
    //                      2           uid3    uid4    uid5    uid6
    //      10 uint8_ts     1           CT      uid0    uid1    uid2
    //                      2           CT      uid3    uid4    uid5
    //                      3           uid6    uid7    uid8    uid9
 
    // Sanity checks
    if (validBits > 80) {
        return STATUS_INVALID;
    }
 
    // Prepare MFRC522
    PCD_ClearRegisterBitMask(CollReg, 0x80);        // ValuesAfterColl=1 => Bits received after collision are cleared.
 
    // Repeat Cascade Level loop until we have a complete UID.
    uidComplete = false;
    while (!uidComplete) {
        // Set the Cascade Level in the SEL uint8_t, find out if we need to use the Cascade Tag in uint8_t 2.
        switch (cascadeLevel) {
            case 1:
                buffer[0] = PICC_CMD_SEL_CL1;
                uidIndex = 0;
                useCascadeTag = validBits && uid->size > 4;    // When we know that the UID has more than 4 uint8_ts
                break;
 
            case 2:
                buffer[0] = PICC_CMD_SEL_CL2;
                uidIndex = 3;
                useCascadeTag = validBits && uid->size > 7;    // When we know that the UID has more than 7 uint8_ts
                break;
 
            case 3:
                buffer[0] = PICC_CMD_SEL_CL3;
                uidIndex = 6;
                useCascadeTag = false;                        // Never used in CL3.
                break;
 
            default:
                return STATUS_INTERNAL_ERROR;
                break;
        }
 
        // How many UID bits are known in this Cascade Level?
        currentLevelKnownBits = validBits - (8 * uidIndex);
        if (currentLevelKnownBits < 0) {
            currentLevelKnownBits = 0;
        }
        // Copy the known bits from uid->uidByte[] to buffer[]
        index = 2; // destination index in buffer[]
        if (useCascadeTag) {
            buffer[index++] = PICC_CMD_CT;
        }
        uint8_t uint8_tsToCopy = currentLevelKnownBits / 8 + (currentLevelKnownBits % 8 ? 1
                                                                                        : 0); // The number of uint8_ts needed to represent the known bits for this level.
        if (uint8_tsToCopy) {
            uint8_t maxBytes = useCascadeTag ? 3
                                             : 4; // Max 4 uint8_ts in each Cascade Level. Only 3 left if we use the Cascade Tag
            if (uint8_tsToCopy > maxBytes) {
                uint8_tsToCopy = maxBytes;
            }
            for (count = 0; count < uint8_tsToCopy; count++) {
                buffer[index++] = uid->uidByte[uidIndex + count];
            }
        }
        // Now that the data has been copied we need to include the 8 bits in CT in currentLevelKnownBits
        if (useCascadeTag) {
            currentLevelKnownBits += 8;
        }
 
        // Repeat anti collision loop until we can transmit all UID bits + BCC and receive a SAK - max 32 iterations.
        selectDone = false;
        while (!selectDone) {
            // Find out how many bits and uint8_ts to send and receive.
            if (currentLevelKnownBits >= 32) { // All UID bits in this Cascade Level are known. This is a SELECT.
                //Serial.print(F("SELECT: currentLevelKnownBits=")); Serial.println(currentLevelKnownBits, DEC);
                buffer[1] = 0x70; // NVB - Number of Valid Bits: Seven whole uint8_ts
                // Calculate BCC - Block Check Character
                buffer[6] = buffer[2] ^ buffer[3] ^ buffer[4] ^ buffer[5];
                // Calculate CRC_A
                result = PCD_CalculateCRC(buffer, 7, &buffer[7]);
                if (result != STATUS_OK) {
                    return result;
                }
                txLastBits = 0; // 0 => All 8 bits are valid.
                bufferUsed = 9;
                // Store response in the last 3 uint8_ts of buffer (BCC and CRC_A - not needed after tx)
                responseBuffer = &buffer[6];
                responseLength = 3;
            } else { // This is an ANTICOLLISION.
                //Serial.print(F("ANTICOLLISION: currentLevelKnownBits=")); Serial.println(currentLevelKnownBits, DEC);
                txLastBits = currentLevelKnownBits % 8;
                count = currentLevelKnownBits / 8;    // Number of whole uint8_ts in the UID part.
                index = 2 + count;                    // Number of whole uint8_ts: SEL + NVB + UIDs
                buffer[1] = (index << 4) + txLastBits;    // NVB - Number of Valid Bits
                bufferUsed = index + (txLastBits ? 1 : 0);
                // Store response in the unused part of buffer
                responseBuffer = &buffer[index];
                responseLength = sizeof(buffer) - index;
            }
 
            // Set bit adjustments
            rxAlign = txLastBits;                                            // Having a separate variable is overkill. But it makes the next line easier to read.
            PCD_WriteRegister(BitFramingReg, (rxAlign << 4) +
                                             txLastBits);    // RxAlign = BitFramingReg[6..4]. TxLastBits = BitFramingReg[2..0]
 
            // Transmit the buffer and receive the response.
            result = PCD_TransceiveData(buffer, bufferUsed, responseBuffer, &responseLength, &txLastBits, rxAlign);
            if (result == STATUS_COLLISION) { // More than one PICC in the field => collision.
                uint8_t valueOfCollReg = PCD_ReadRegister(
                        CollReg); // CollReg[7..0] bits are: ValuesAfterColl reserved CollPosNotValid CollPos[4:0]
                if (valueOfCollReg & 0x20) { // CollPosNotValid
                    return STATUS_COLLISION; // Without a valid collision position we cannot continue
                }
                uint8_t collisionPos = valueOfCollReg & 0x1F; // Values 0-31, 0 means bit 32.
                if (collisionPos == 0) {
                    collisionPos = 32;
                }
                if (collisionPos <= currentLevelKnownBits) { // No progress - should not happen
                    return STATUS_INTERNAL_ERROR;
                }
                // Choose the PICC with the bit set.
                currentLevelKnownBits = collisionPos;
                count = currentLevelKnownBits % 8; // The bit to modify
                checkBit = (currentLevelKnownBits - 1) % 8;
                index = 1 + (currentLevelKnownBits / 8) + (count ? 1 : 0); // First uint8_t is index 0.
                buffer[index] |= (1 << checkBit);
            } else if (result != STATUS_OK) {
                return result;
            } else { // STATUS_OK
                if (currentLevelKnownBits >= 32) { // This was a SELECT.
                    selectDone = true; // No more anticollision
                    // We continue below outside the while.
                } else { // This was an ANTICOLLISION.
                    // We now have all 32 bits of the UID in this Cascade Level
                    currentLevelKnownBits = 32;
                    // Run loop again to do the SELECT.
                }
            }
        } // End of while (!selectDone)
 
        // We do not check the CBB - it was constructed by us above.
 
        // Copy the found UID uint8_ts from buffer[] to uid->uidByte[]
        index = (buffer[2] == PICC_CMD_CT) ? 3 : 2; // source index in buffer[]
        uint8_tsToCopy = (buffer[2] == PICC_CMD_CT) ? 3 : 4;
        for (count = 0; count < uint8_tsToCopy; count++) {
            uid->uidByte[uidIndex + count] = buffer[index++];
        }
 
        // Check response SAK (Select Acknowledge)
        if (responseLength != 3 || txLastBits != 0) { // SAK must be exactly 24 bits (1 uint8_t + CRC_A).
            return STATUS_ERROR;
        }
        // Verify CRC_A - do our own calculation and store the control in buffer[2..3] - those uint8_ts are not needed anymore.
        result = PCD_CalculateCRC(responseBuffer, 1, &buffer[2]);
        if (result != STATUS_OK) {
            return result;
        }
        if ((buffer[2] != responseBuffer[1]) || (buffer[3] != responseBuffer[2])) {
            return STATUS_CRC_WRONG;
        }
        if (responseBuffer[0] & 0x04) { // Cascade bit set - UID not complete yes
            cascadeLevel++;
        } else {
            uidComplete = true;
            uid->sak = responseBuffer[0];
        }
    } // End of while (!uidComplete)
 
    // Set correct uid->size
    uid->size = 3 * cascadeLevel + 1;
 
    return STATUS_OK;
} // End PICC_Select()
 
mfrc522_drv::StatusCode mfrc522_drv::PICC_HaltA() {
    mfrc522_drv::StatusCode result;
    uint8_t buffer[4];
 
    // Build command buffer
    buffer[0] = PICC_CMD_HLTA;
    buffer[1] = 0;
    // Calculate CRC_A
    result = PCD_CalculateCRC(buffer, 2, &buffer[2]);
    if (result != STATUS_OK) {
        return result;
    }
 
    // Send the command.
    // The standard says:
    //      If the PICC responds with any modulation during a period of 1 ms after the end of the frame containing the
    //      HLTA command, this response shall be interpreted as 'not acknowledge'.
    // We interpret that this way: Only STATUS_TIMEOUT is a success.
    result = PCD_TransceiveData(buffer, sizeof(buffer), nullptr, 0);
    if (result == STATUS_TIMEOUT) {
        return STATUS_OK;
    }
    if (result == STATUS_OK) { // That is ironically NOT ok in this case ;-)
        return STATUS_ERROR;
    }
    return result;
} // End PICC_HaltA()
 
// Functions for communicating with MIFARE PICCs
 
mfrc522_drv::StatusCode
mfrc522_drv::PCD_Authenticate(uint8_t command,        
                          uint8_t blockAddr,    
                          MIFARE_Key *key,    
                          Uid *uid            
) {
    uint8_t waitIRq = 0x10;        // IdleIRq
 
    // Build command buffer
    uint8_t sendData[12];
    sendData[0] = command;
    sendData[1] = blockAddr;
    for (uint8_t i = 0; i < MF_KEY_SIZE; i++) {    // 6 key uint8_ts
        sendData[2 + i] = key->keyByte[i];
    }
    // Use the last uid uint8_ts as specified in http://cache.nxp.com/documents/application_note/AN10927.pdf
    // section 3.2.5 "MIFARE Classic Authentication".
    // The only missed case is the MF1Sxxxx shortcut activation,
    // but it requires cascade tag (CT) uint8_t, that is not part of uid.
    for (uint8_t i = 0; i < 4; i++) {                // The last 4 uint8_ts of the UID
        sendData[8 + i] = uid->uidByte[i + uid->size - 4];
    }
 
    // Start the authentication.
    return PCD_CommunicateWithPICC(PCD_MFAuthent, waitIRq, &sendData[0], sizeof(sendData));
} // End PCD_Authenticate()
 
void mfrc522_drv::PCD_StopCrypto1() {
    // Clear MFCrypto1On bit
    PCD_ClearRegisterBitMask(Status2Reg,
                             0x08); // Status2Reg[7..0] bits are: TempSensClear I2CForceHS reserved reserved MFCrypto1On ModemState[2:0]
} // End PCD_StopCrypto1()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_Read(
        uint8_t blockAddr,    
        uint8_t *buffer,        
        uint8_t *bufferSize    
) {
    mfrc522_drv::StatusCode result;
 
    // Sanity check
    if (buffer == nullptr || *bufferSize < 18) {
        return STATUS_NO_ROOM;
    }
 
    // Build command buffer
    buffer[0] = PICC_CMD_MF_READ;
    buffer[1] = blockAddr;
    // Calculate CRC_A
    result = PCD_CalculateCRC(buffer, 2, &buffer[2]);
    if (result != STATUS_OK) {
        return result;
    }
 
    // Transmit the buffer and receive the response, validate CRC_A.
    return PCD_TransceiveData(buffer, 4, buffer, bufferSize, nullptr, 0, true);
} // End MIFARE_Read()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_Write(
        uint8_t blockAddr, 
        uint8_t *buffer,    
        uint8_t bufferSize    
) {
    mfrc522_drv::StatusCode result;
 
    // Sanity check
    if (buffer == nullptr || bufferSize < 16) {
        return STATUS_INVALID;
    }
 
    // Mifare Classic protocol requires two communications to perform a write.
    // Step 1: Tell the PICC we want to write to block blockAddr.
    uint8_t cmdBuffer[2];
    cmdBuffer[0] = PICC_CMD_MF_WRITE;
    cmdBuffer[1] = blockAddr;
    result = PCD_MIFARE_Transceive(cmdBuffer, 2); // Adds CRC_A and checks that the response is MF_ACK.
    if (result != STATUS_OK) {
        return result;
    }
 
    // Step 2: Transfer the data
    result = PCD_MIFARE_Transceive(buffer, bufferSize); // Adds CRC_A and checks that the response is MF_ACK.
    if (result != STATUS_OK) {
        return result;
    }
 
    return STATUS_OK;
} // End MIFARE_Write()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_Ultralight_Write(uint8_t page,        
                                                     uint8_t *buffer,    
                                                     uint8_t bufferSize    
) {
    mfrc522_drv::StatusCode result;
 
    // Sanity check
    if (buffer == nullptr || bufferSize < 4) {
        return STATUS_INVALID;
    }
 
    // Build commmand buffer
    uint8_t cmdBuffer[6];
    cmdBuffer[0] = PICC_CMD_UL_WRITE;
    cmdBuffer[1] = page;
    memcpy(&cmdBuffer[2], buffer, 4);
 
    // Perform the write
    result = PCD_MIFARE_Transceive(cmdBuffer, 6); // Adds CRC_A and checks that the response is MF_ACK.
    if (result != STATUS_OK) {
        return result;
    }
    return STATUS_OK;
} // End MIFARE_Ultralight_Write()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_Decrement(uint8_t blockAddr, 
                                              int32_t delta        
) {
    return MIFARE_TwoStepHelper(PICC_CMD_MF_DECREMENT, blockAddr, delta);
} // End MIFARE_Decrement()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_Increment(uint8_t blockAddr, 
                                              int32_t delta        
) {
    return MIFARE_TwoStepHelper(PICC_CMD_MF_INCREMENT, blockAddr, delta);
} // End MIFARE_Increment()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_Restore(uint8_t blockAddr 
) {
    // The datasheet describes Restore as a two step operation, but does not explain what data to transfer in step 2.
    // Doing only a single step does not work, so I chose to transfer 0L in step two.
    return MIFARE_TwoStepHelper(PICC_CMD_MF_RESTORE, blockAddr, 0L);
} // End MIFARE_Restore()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_TwoStepHelper(uint8_t command,    
                                                  uint8_t blockAddr,    
                                                  int32_t data        
) {
    mfrc522_drv::StatusCode result;
    uint8_t cmdBuffer[2]; // We only need room for 2 uint8_ts.
 
    // Step 1: Tell the PICC the command and block address
    cmdBuffer[0] = command;
    cmdBuffer[1] = blockAddr;
    result = PCD_MIFARE_Transceive(cmdBuffer, 2); // Adds CRC_A and checks that the response is MF_ACK.
    if (result != STATUS_OK) {
        return result;
    }
 
    // Step 2: Transfer the data
    result = PCD_MIFARE_Transceive((uint8_t *) &data, 4, true); // Adds CRC_A and accept timeout as success.
    if (result != STATUS_OK) {
        return result;
    }
 
    return STATUS_OK;
} // End MIFARE_TwoStepHelper()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_Transfer(uint8_t blockAddr 
) {
    mfrc522_drv::StatusCode result;
    uint8_t cmdBuffer[2]; // We only need room for 2 uint8_ts.
 
    // Tell the PICC we want to transfer the result into block blockAddr.
    cmdBuffer[0] = PICC_CMD_MF_TRANSFER;
    cmdBuffer[1] = blockAddr;
    result = PCD_MIFARE_Transceive(cmdBuffer, 2); // Adds CRC_A and checks that the response is MF_ACK.
    if (result != STATUS_OK) {
        return result;
    }
    return STATUS_OK;
} // End MIFARE_Transfer()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_GetValue(uint8_t blockAddr, int32_t *value) {
    mfrc522_drv::StatusCode status;
    uint8_t buffer[18];
    uint8_t size = sizeof(buffer);
 
    // Read the block
    status = MIFARE_Read(blockAddr, buffer, &size);
    if (status == STATUS_OK) {
        // Extract the value
        *value = (int32_t(buffer[3]) << 24) | (int32_t(buffer[2]) << 16) | (int32_t(buffer[1]) << 8) |
                 int32_t(buffer[0]);
    }
    return status;
} // End MIFARE_GetValue()
 
mfrc522_drv::StatusCode mfrc522_drv::MIFARE_SetValue(uint8_t blockAddr, int32_t value) {
    uint8_t buffer[18];
 
    // Translate the int32_t into 4 uint8_ts; repeated 2x in value block
    buffer[0] = buffer[8] = (value & 0xFF);
    buffer[1] = buffer[9] = (value & 0xFF00) >> 8;
    buffer[2] = buffer[10] = (value & 0xFF0000) >> 16;
    buffer[3] = buffer[11] = (value & 0xFF000000) >> 24;
    // Inverse 4 uint8_ts also found in value block
    buffer[4] = ~buffer[0];
    buffer[5] = ~buffer[1];
    buffer[6] = ~buffer[2];
    buffer[7] = ~buffer[3];
    // Address 2x with inverse address 2x
    buffer[12] = buffer[14] = blockAddr;
    buffer[13] = buffer[15] = ~blockAddr;
 
    // Write the whole data block
    return MIFARE_Write(blockAddr, buffer, 16);
} // End MIFARE_SetValue()
 
mfrc522_drv::StatusCode mfrc522_drv::PCD_NTAG216_AUTH(uint8_t *passWord, uint8_t pACK[]) //Authenticate with 32bit password
{
    // TODO: Fix cmdBuffer length and rxlength. They really should match.
    //       (Better still, rxlength should not even be necessary.)
 
    mfrc522_drv::StatusCode result;
    uint8_t cmdBuffer[18]; // We need room for 16 uint8_ts data and 2 uint8_ts CRC_A.
 
    cmdBuffer[0] = 0x1B; //Comando de autentificacion
 
    for (uint8_t i = 0; i < 4; i++)
        cmdBuffer[i + 1] = passWord[i];
 
    result = PCD_CalculateCRC(cmdBuffer, 5, &cmdBuffer[5]);
 
    if (result != STATUS_OK) {
        return result;
    }
 
    // Transceive the data, store the reply in cmdBuffer[]
    uint8_t waitIRq = 0x30;    // RxIRq and IdleIRq
//  uint8_t cmdBufferSize   = sizeof(cmdBuffer);
    uint8_t validBits = 0;
    uint8_t rxlength = 5;
    result = PCD_CommunicateWithPICC(PCD_Transceive, waitIRq, cmdBuffer, 7, cmdBuffer, &rxlength, &validBits);
 
    pACK[0] = cmdBuffer[0];
    pACK[1] = cmdBuffer[1];
 
    if (result != STATUS_OK) {
        return result;
    }
 
    return STATUS_OK;
} // End PCD_NTAG216_AUTH()
 
 
// Support functions
 
mfrc522_drv::StatusCode mfrc522_drv::PCD_MIFARE_Transceive(
        uint8_t *sendData,        
        uint8_t sendLen,        
        bool acceptTimeout    
) {
    mfrc522_drv::StatusCode result;
    uint8_t cmdBuffer[18]; // We need room for 16 uint8_ts data and 2 uint8_ts CRC_A.
 
    // Sanity check
    if (sendData == nullptr || sendLen > 16) {
        return STATUS_INVALID;
    }
 
    // Copy sendData[] to cmdBuffer[] and add CRC_A
    memcpy(cmdBuffer, sendData, sendLen);
    result = PCD_CalculateCRC(cmdBuffer, sendLen, &cmdBuffer[sendLen]);
    if (result != STATUS_OK) {
        return result;
    }
    sendLen += 2;
 
    // Transceive the data, store the reply in cmdBuffer[]
    uint8_t waitIRq = 0x30;        // RxIRq and IdleIRq
    uint8_t cmdBufferSize = sizeof(cmdBuffer);
    uint8_t validBits = 0;
    result = PCD_CommunicateWithPICC(PCD_Transceive, waitIRq, cmdBuffer, sendLen, cmdBuffer, &cmdBufferSize,
                                     &validBits);
    if (acceptTimeout && result == STATUS_TIMEOUT) {
        return STATUS_OK;
    }
    if (result != STATUS_OK) {
        return result;
    }
    // The PICC must reply with a 4 bit ACK
    if (cmdBufferSize != 1 || validBits != 4) {
        return STATUS_ERROR;
    }
    if (cmdBuffer[0] != MF_ACK) {
        return STATUS_MIFARE_NACK;
    }
    return STATUS_OK;
} // End PCD_MIFARE_Transceive()
 
const char *mfrc522_drv::GetStatusCodeName(mfrc522_drv::StatusCode code    
) {
    switch (code) {
        case STATUS_OK:
            return ("Success.");
        case STATUS_ERROR:
            return ("Error in communication.");
        case STATUS_COLLISION:
            return ("Collision detected.");
        case STATUS_TIMEOUT:
            return ("Timeout in communication.");
        case STATUS_NO_ROOM:
            return ("A buffer is not big enough.");
        case STATUS_INTERNAL_ERROR:
            return ("Internal error in the code. Should not happen.");
        case STATUS_INVALID:
            return ("Invalid argument.");
        case STATUS_CRC_WRONG:
            return ("The CRC_A does not match.");
        case STATUS_MIFARE_NACK:
            return ("A MIFARE PICC responded with NAK.");
        default:
            return ("Unknown error");
    }
} // End GetStatusCodeName()
 
mfrc522_drv::PICC_Type mfrc522_drv::PICC_GetType(uint8_t sak        
) {
    // http://www.nxp.com/documents/application_note/AN10833.pdf
    // 3.2 Coding of Select Acknowledge (SAK)
    // ignore 8-bit (iso14443 starts with LSBit = bit 1)
    // fixes wrong type for manufacturer Infineon (http://nfc-tools.org/index.php?title=ISO14443A)
    sak &= 0x7F;
    switch (sak) {
        case 0x04:
            return PICC_TYPE_NOT_COMPLETE;    // UID not complete
        case 0x09:
            return PICC_TYPE_MIFARE_MINI;
        case 0x08:
            return PICC_TYPE_MIFARE_1K;
        case 0x18:
            return PICC_TYPE_MIFARE_4K;
        case 0x00:
            return PICC_TYPE_MIFARE_UL;
        case 0x10:
        case 0x11:
            return PICC_TYPE_MIFARE_PLUS;
        case 0x01:
            return PICC_TYPE_TNP3XXX;
        case 0x20:
            return PICC_TYPE_ISO_14443_4;
        case 0x40:
            return PICC_TYPE_ISO_18092;
        default:
            return PICC_TYPE_UNKNOWN;
    }
} // End PICC_GetType()
 
const char *mfrc522_drv::PICC_GetTypeName(PICC_Type piccType    
) {
    switch (piccType) {
        case PICC_TYPE_ISO_14443_4:
            return ("PICC compliant with ISO/IEC 14443-4");
        case PICC_TYPE_ISO_18092:
            return ("PICC compliant with ISO/IEC 18092 (NFC)");
        case PICC_TYPE_MIFARE_MINI:
            return ("MIFARE Mini, 320 uint8_ts");
        case PICC_TYPE_MIFARE_1K:
            return ("MIFARE 1KB");
        case PICC_TYPE_MIFARE_4K:
            return ("MIFARE 4KB");
        case PICC_TYPE_MIFARE_UL:
            return ("MIFARE Ultralight or Ultralight C");
        case PICC_TYPE_MIFARE_PLUS:
            return ("MIFARE Plus");
        case PICC_TYPE_MIFARE_DESFIRE:
            return ("MIFARE DESFire");
        case PICC_TYPE_TNP3XXX:
            return ("MIFARE TNP3XXX");
        case PICC_TYPE_NOT_COMPLETE:
            return ("SAK indicates UID is not complete.");
        case PICC_TYPE_UNKNOWN:
        default:
            return ("Unknown type");
    }
} // End PICC_GetTypeName()
 
void mfrc522_drv::PCD_DumpVersionToSerial() {
    // Get the MFRC522 firmware version
    uint8_t v = PCD_ReadRegister(VersionReg);
    printf("Firmware Version: 0x");
    printf("%x", v);
    // Lookup which version
    switch (v) {
        case 0x88:
            printf(" = (clone)\n");
            break;
        case 0x90:
            printf((" = v0.0\n"));
            break;
        case 0x91:
            printf((" = v1.0\n"));
            break;
        case 0x92:
            printf((" = v2.0\n"));
            break;
        case 0x12:
            printf(" = counterfeit chip\n");
            break;
        default:
            printf(" = (unknown)\n");
    }
    // When 0x00 or 0xFF is returned, communication probably failed
    if ((v == 0x00) || (v == 0xFF))
        printf("WARNING: Communication failure, is the MFRC522 properly connected?\n");
} // End PCD_DumpVersionToSerial()
 
void mfrc522_drv::PICC_DumpToSerial(Uid *uid    
) {
    MIFARE_Key key;
 
    // Dump UID, SAK and Type
    PICC_DumpDetailsToSerial(uid);
 
    // Dump contents
    PICC_Type piccType = PICC_GetType(uid->sak);
    switch (piccType) {
        case PICC_TYPE_MIFARE_MINI:
        case PICC_TYPE_MIFARE_1K:
        case PICC_TYPE_MIFARE_4K:
            // All keys are set to FFFFFFFFFFFFh at chip delivery from the factory.
            for (uint8_t i = 0; i < 6; i++) {
                key.keyByte[i] = 0xFF;
            }
            PICC_DumpMifareClassicToSerial(uid, piccType, &key);
            break;
 
        case PICC_TYPE_MIFARE_UL:
            PICC_DumpMifareUltralightToSerial();
            break;
 
        case PICC_TYPE_ISO_14443_4:
        case PICC_TYPE_MIFARE_DESFIRE:
        case PICC_TYPE_ISO_18092:
        case PICC_TYPE_MIFARE_PLUS:
        case PICC_TYPE_TNP3XXX:
            printf("Dumping memory contents not implemented for that PICC type.\n");
            break;
 
        case PICC_TYPE_UNKNOWN:
        case PICC_TYPE_NOT_COMPLETE:
        default:
            break; // No memory dump here
    }
 
    printf("\n");
    PICC_HaltA(); // Already done if it was a MIFARE Classic PICC.
} // End PICC_DumpToSerial()
 
void mfrc522_drv::PICC_DumpDetailsToSerial(Uid *uid) {    
    // UID
    printf("Card UID:");
    for (uint8_t i = 0; i < uid->size; i++) {
        if (uid->uidByte[i] < 0x10)
            printf(" 0");
        else
            printf(" ");
        printf("%x", uid->uidByte[i]);
    }
    printf("\n");
 
    // SAK
    printf("Card SAK: ");
    if (uid->sak < 0x10)
        printf("0");
    printf("%x\n", uid->sak);
 
    // (suggested) PICC type
    PICC_Type piccType = PICC_GetType(uid->sak);
    printf("PICC type: ");
    printf(PICC_GetTypeName(piccType));
    printf("\n");
} // End PICC_DumpDetailsToSerial()
 
void mfrc522_drv::PICC_DumpMifareClassicToSerial(
        Uid *uid,            
        PICC_Type piccType,    
        MIFARE_Key *key        
) {
    uint8_t no_of_sectors = 0;
    switch (piccType) {
        case PICC_TYPE_MIFARE_MINI:
            // Has 5 sectors * 4 blocks/sector * 16 uint8_ts/block = 320 uint8_ts.
            no_of_sectors = 5;
            break;
 
        case PICC_TYPE_MIFARE_1K:
            // Has 16 sectors * 4 blocks/sector * 16 uint8_ts/block = 1024 uint8_ts.
            no_of_sectors = 16;
            break;
 
        case PICC_TYPE_MIFARE_4K:
            // Has (32 sectors * 4 blocks/sector + 8 sectors * 16 blocks/sector) * 16 uint8_ts/block = 4096 uint8_ts.
            no_of_sectors = 40;
            break;
 
        default: // Should not happen. Ignore.
            break;
    }
 
    // Dump sectors, highest address first.
    if (no_of_sectors) {
        printf("Sector Block   0  1  2  3   4  5  6  7   8  9 10 11  12 13 14 15  AccessBits\n");
        for (int8_t i = no_of_sectors - 1; i >= 0; i--) {
            PICC_DumpMifareClassicSectorToSerial(uid, key, i);
        }
    }
    PICC_HaltA(); // Halt the PICC before stopping the encrypted session.
    PCD_StopCrypto1();
} // End PICC_DumpMifareClassicToSerial()
 
void mfrc522_drv::PICC_DumpMifareClassicSectorToSerial(
        Uid *uid,            
        MIFARE_Key *key,    
        uint8_t sector            
) {
    mfrc522_drv::StatusCode status;
    uint8_t firstBlock;        // Address of lowest address to dump actually last block dumped)
    uint8_t no_of_blocks;        // Number of blocks in sector
    bool isSectorTrailer;    // Set to true while handling the "last" (ie highest address) in the sector.
 
    // The access bits are stored in a peculiar fashion.
    // There are four groups:
    //      g[3]    Access bits for the sector trailer, block 3 (for sectors 0-31) or block 15 (for sectors 32-39)
    //      g[2]    Access bits for block 2 (for sectors 0-31) or blocks 10-14 (for sectors 32-39)
    //      g[1]    Access bits for block 1 (for sectors 0-31) or blocks 5-9 (for sectors 32-39)
    //      g[0]    Access bits for block 0 (for sectors 0-31) or blocks 0-4 (for sectors 32-39)
    // Each group has access bits [C1 C2 C3]. In this code C1 is MSB and C3 is LSB.
    // The four CX bits are stored together in a nible cx and an inverted nible cx_.
    uint8_t c1, c2, c3;        // Nibbles
    uint8_t c1_, c2_, c3_;        // Inverted nibbles
    bool invertedError;        // True if one of the inverted nibbles did not match
    uint8_t g[4];                // Access bits for each of the four groups.
    uint8_t group;                // 0-3 - active group for access bits
    bool firstInGroup;        // True for the first block dumped in the group
 
    // Determine position and size of sector.
    if (sector < 32) { // Sectors 0..31 has 4 blocks each
        no_of_blocks = 4;
        firstBlock = sector * no_of_blocks;
    } else if (sector < 40) { // Sectors 32-39 has 16 blocks each
        no_of_blocks = 16;
        firstBlock = 128 + (sector - 32) * no_of_blocks;
    } else { // Illegal input, no MIFARE Classic PICC has more than 40 sectors.
        return;
    }
 
    // Dump blocks, highest address first.
    uint8_t uint8_tCount;
    uint8_t buffer[18];
    uint8_t blockAddr;
    isSectorTrailer = true;
    invertedError = false;    // Avoid "unused variable" warning.
    for (int8_t blockOffset = no_of_blocks - 1; blockOffset >= 0; blockOffset--) {
        blockAddr = firstBlock + blockOffset;
        // Sector number - only on first line
        if (isSectorTrailer) {
            if (sector < 10)
                printf("   "); // Pad with spaces
            else
                printf("  "); // Pad with spaces
            printf("%d", sector);
            printf("   ");
        } else {
            printf("       ");
        }
        // Block number
        if (blockAddr < 10)
            printf("   "); // Pad with spaces
        else {
            if (blockAddr < 100)
                printf("  "); // Pad with spaces
            else
                printf(" "); // Pad with spaces
        }
        printf("%d", blockAddr);
        printf("  ");
        // Establish encrypted communications before reading the first block
        if (isSectorTrailer) {
            status = PCD_Authenticate(PICC_CMD_MF_AUTH_KEY_A, firstBlock, key, uid);
            if (status != STATUS_OK) {
                printf("PCD_Authenticate() failed: ");
                printf(GetStatusCodeName(status));
                printf("\n");
                return;
            }
        }
        // Read block
        uint8_tCount = sizeof(buffer);
        status = MIFARE_Read(blockAddr, buffer, &uint8_tCount);
        if (status != STATUS_OK) {
            printf("MIFARE_Read() failed: ");
            printf(GetStatusCodeName(status));
            printf("\n");
            continue;
        }
        // Dump data
        for (uint8_t index = 0; index < 16; index++) {
            if (buffer[index] < 0x10)
                printf(" 0");
            else
                printf(" ");
            printf("%x", buffer[index]);
            if ((index % 4) == 3) {
                printf(" ");
            }
        }
        // Parse sector trailer data
        if (isSectorTrailer) {
            c1 = buffer[7] >> 4;
            c2 = buffer[8] & 0xF;
            c3 = buffer[8] >> 4;
            c1_ = buffer[6] & 0xF;
            c2_ = buffer[6] >> 4;
            c3_ = buffer[7] & 0xF;
            invertedError = (c1 != (~c1_ & 0xF)) || (c2 != (~c2_ & 0xF)) || (c3 != (~c3_ & 0xF));
            g[0] = ((c1 & 1) << 2) | ((c2 & 1) << 1) | ((c3 & 1) << 0);
            g[1] = ((c1 & 2) << 1) | ((c2 & 2) << 0) | ((c3 & 2) >> 1);
            g[2] = ((c1 & 4) << 0) | ((c2 & 4) >> 1) | ((c3 & 4) >> 2);
            g[3] = ((c1 & 8) >> 1) | ((c2 & 8) >> 2) | ((c3 & 8) >> 3);
            isSectorTrailer = false;
        }
 
        // Which access group is this block in?
        if (no_of_blocks == 4) {
            group = blockOffset;
            firstInGroup = true;
        } else {
            group = blockOffset / 5;
            firstInGroup = (group == 3) || (group != (blockOffset + 1) / 5);
        }
 
        if (firstInGroup) {
            // Print access bits
            printf(" [ ");
            printf("%d", (g[group] >> 2) & 1);
            printf(" ");
            printf("%d", (g[group] >> 1) & 1);
            printf(" ");
            printf("%d", (g[group] >> 0) & 1);
            printf(" ] ");
            if (invertedError) {
                printf(" Inverted access bits did not match! ");
            }
        }
 
        if (group != 3 && (g[group] == 1 || g[group] == 6)) { // Not a sector trailer, a value block
            int32_t value = (int32_t(buffer[3]) << 24) | (int32_t(buffer[2]) << 16) | (int32_t(buffer[1]) << 8) |
                            int32_t(buffer[0]);
            printf(" Value=0x");
            printf("%lx", value);
            printf(" Adr=0x");
            printf("%x", buffer[12]);
        }
        printf("\n");
    }
    return;
} // End PICC_DumpMifareClassicSectorToSerial()
 
void mfrc522_drv::PICC_DumpMifareUltralightToSerial() {
    mfrc522_drv::StatusCode status;
    uint8_t uint8_tCount;
    uint8_t buffer[18];
    uint8_t i;
 
    printf("Page  0  1  2  3");
    // Try the mpages of the original Ultralight. Ultralight C has more pages.
    for (uint8_t page = 0; page < 16; page += 4) { // Read returns data for 4 pages at a time.
        // Read pages
        uint8_tCount = sizeof(buffer);
        status = MIFARE_Read(page, buffer, &uint8_tCount);
        if (status != STATUS_OK) {
            printf("MIFARE_Read() failed: ");
            printf(GetStatusCodeName(status));
            break;
        }
        // Dump data
        for (uint8_t offset = 0; offset < 4; offset++) {
            i = page + offset;
            if (i < 10)
                printf("  "); // Pad with spaces
            else
                printf(" "); // Pad with spaces
            printf("%d",i);
            printf("  ");
            for (uint8_t index = 0; index < 4; index++) {
                i = 4 * offset + index;
                if (buffer[i] < 0x10)
                    printf(" 0");
                else
                    printf(" ");
                printf("%02x", buffer[i]);
            }
            printf("\n");
        }
    }
} // End PICC_DumpMifareUltralightToSerial()
 
void mfrc522_drv::MIFARE_SetAccessBits(
        uint8_t *accessBitBuffer,    
        uint8_t g0,                
        uint8_t g1,                
        uint8_t g2,                
        uint8_t g3                    
) {
    uint8_t c1 = ((g3 & 4) << 1) | ((g2 & 4) << 0) | ((g1 & 4) >> 1) | ((g0 & 4) >> 2);
    uint8_t c2 = ((g3 & 2) << 2) | ((g2 & 2) << 1) | ((g1 & 2) << 0) | ((g0 & 2) >> 1);
    uint8_t c3 = ((g3 & 1) << 3) | ((g2 & 1) << 2) | ((g1 & 1) << 1) | ((g0 & 1) << 0);
 
    accessBitBuffer[0] = (~c2 & 0xF) << 4 | (~c1 & 0xF);
    accessBitBuffer[1] = c1 << 4 | (~c3 & 0xF);
    accessBitBuffer[2] = c3 << 4 | c2;
} // End MIFARE_SetAccessBits()
 
 
bool mfrc522_drv::MIFARE_OpenUidBackdoor(bool logErrors) {
    // Magic sequence:
    // > 50 00 57 CD (HALT + CRC)
    // > 40 (7 bits only)
    // < A (4 bits only)
    // > 43
    // < A (4 bits only)
    // Then you can write to sector 0 without authenticating
 
    PICC_HaltA(); // 50 00 57 CD
 
    uint8_t cmd = 0x40;
    uint8_t validBits = 7; /* Our command is only 7 bits. After receiving card response,
                          this will contain amount of valid response bits. */
    uint8_t response[32]; // Card's response is written here
    uint8_t received = sizeof(response);
    mfrc522_drv::StatusCode status = PCD_TransceiveData(&cmd, (uint8_t) 1, response, &received, &validBits, (uint8_t) 0,
                                                        false); // 40
    if (status != STATUS_OK) {
        if (logErrors) {
            printf(
                    "Card did not respond to 0x40 after HALT command. Are you sure it is a UID changeable one?");
            printf("Error name: ");
            printf(GetStatusCodeName(status));
            printf("\n");
        }
        return false;
    }
    if (received != 1 || response[0] != 0x0A) {
        if (logErrors) {
            printf("Got bad response on backdoor 0x40 command: ");
            printf("%x", response[0]);
            printf(" (");
            printf("%d", validBits);
            printf(" valid bits)\r\n");
        }
        return false;
    }
 
    cmd = 0x43;
    validBits = 8;
    status = PCD_TransceiveData(&cmd, (uint8_t) 1, response, &received, &validBits, (uint8_t) 0, false); // 43
    if (status != STATUS_OK) {
        if (logErrors) {
            printf("Error in communication at command 0x43, after successfully executing 0x40\n");
            printf("Error name: ");
            printf("%s", GetStatusCodeName(status));
        }
        return false;
    }
    if (received != 1 || response[0] != 0x0A) {
        if (logErrors) {
            printf("Got bad response on backdoor 0x43 command: ");
            printf("%x", response[0]);
            printf(" (");
            printf("%d", validBits);
            printf(" valid bits)\r\n");
        }
        return false;
    }
 
    // You can now write to sector 0 without authenticating!
    return true;
} // End MIFARE_OpenUidBackdoor()
 
bool mfrc522_drv::MIFARE_SetUid(uint8_t *newUid, uint8_t uidSize, bool logErrors) {
 
    // UID + BCC uint8_t can not be larger than 16 together
    if (!newUid || !uidSize || uidSize > 15) {
        if (logErrors) {
            printf("New UID buffer empty, size 0, or size > 15 given\n");
        }
        return false;
    }
 
    // Authenticate for reading
    MIFARE_Key key = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
    mfrc522_drv::StatusCode status = PCD_Authenticate(mfrc522_drv::PICC_CMD_MF_AUTH_KEY_A, (uint8_t) 1, &key, &uid);
    if (status != STATUS_OK) {
 
        if (status == STATUS_TIMEOUT) {
            // We get a read timeout if no card is selected yet, so let's select one
 
            // Wake the card up again if sleeping
//            uint8_t atqa_answer[2];
//            uint8_t atqa_size = 2;
//            PICC_WakeupA(atqa_answer, &atqa_size);
 
            if (!PICC_IsNewCardPresent() || !PICC_ReadCardSerial()) {
                printf("No card was previously selected, and none are available. Failed to set UID.\n");
                return false;
            }
 
            status = PCD_Authenticate(mfrc522_drv::PICC_CMD_MF_AUTH_KEY_A, (uint8_t) 1, &key, &uid);
            if (status != STATUS_OK) {
                // We tried, time to give up
                if (logErrors) {
                    printf("Failed to authenticate to card for reading, could not set UID: \n");
                    printf("%s\n", GetStatusCodeName(status));
                }
                return false;
            }
        } else {
            if (logErrors) {
                printf("PCD_Authenticate() failed: ");
                printf("%s\n", GetStatusCodeName(status));
            }
            return false;
        }
    }
 
    // Read block 0
    uint8_t block0_buffer[18];
    uint8_t uint8_tCount = sizeof(block0_buffer);
    status = MIFARE_Read((uint8_t) 0, block0_buffer, &uint8_tCount);
    if (status != STATUS_OK) {
        if (logErrors) {
            printf("MIFARE_Read() failed: ");
            printf("%s\n", GetStatusCodeName(status));
            printf("Are you sure your KEY A for sector 0 is 0xFFFFFFFFFFFF?\n");
        }
        return false;
    }
 
    // Write new UID to the data we just read, and calculate BCC uint8_t
    uint8_t bcc = 0;
    for (uint8_t i = 0; i < uidSize; i++) {
        block0_buffer[i] = newUid[i];
        bcc ^= newUid[i];
    }
 
    // Write BCC uint8_t to buffer
    block0_buffer[uidSize] = bcc;
 
    // Stop encrypted traffic so we can send raw uint8_ts
    PCD_StopCrypto1();
 
    // Activate UID backdoor
    if (!MIFARE_OpenUidBackdoor(logErrors)) {
        if (logErrors) {
            printf("Activating the UID backdoor failed.\n");
        }
        return false;
    }
 
    // Write modified block 0 back to card
    status = MIFARE_Write((uint8_t) 0, block0_buffer, (uint8_t) 16);
    if (status != STATUS_OK) {
        if (logErrors) {
            printf("MIFARE_Write() failed: \n");
            printf("%s\n", GetStatusCodeName(status));
        }
        return false;
    }
 
    // Wake the card up again
    uint8_t atqa_answer[2];
    uint8_t atqa_size = 2;
    PICC_WakeupA(atqa_answer, &atqa_size);
 
    return true;
}
 
bool mfrc522_drv::MIFARE_UnbrickUidSector(bool logErrors) {
    MIFARE_OpenUidBackdoor(logErrors);
 
    uint8_t block0_buffer[] = {0x01, 0x02, 0x03, 0x04, 0x04, 0x08, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                               0x00};
 
    // Write modified block 0 back to card
    mfrc522_drv::StatusCode status = MIFARE_Write((uint8_t) 0, block0_buffer, (uint8_t) 16);
    if (status != STATUS_OK) {
        if (logErrors) {
            printf("MIFARE_Write() failed: \n");
            printf("%s\n", GetStatusCodeName(status));
        }
        return false;
    }
    return true;
}
 
// Convenience functions - does not add extra functionality
 
bool mfrc522_drv::PICC_IsNewCardPresent() {
    uint8_t bufferATQA[2];
    uint8_t bufferSize = sizeof(bufferATQA);
 
    // Reset baud rates
    PCD_WriteRegister(TxModeReg, 0x00);
    PCD_WriteRegister(RxModeReg, 0x00);
    // Reset ModWidthReg
    PCD_WriteRegister(ModWidthReg, 0x26);
 
    mfrc522_drv::StatusCode result = PICC_RequestA(bufferATQA, &bufferSize);
    return (result == STATUS_OK || result == STATUS_COLLISION);
}
 
bool mfrc522_drv::PICC_ReadCardSerial() {
    mfrc522_drv::StatusCode result = PICC_Select(&uid);
    return (result == STATUS_OK);
}