Martin Olejar
MFRC522 example project for FRDM
MFRC522.cpp
- Committer:
- AtomX
- Date:
- 2013-12-14
- Revision:
- 0:1d9c7c0b5015
File content as of revision 0:1d9c7c0b5015:
/*
* MFRC522.cpp - Library to use ARDUINO RFID MODULE KIT 13.56 MHZ WITH TAGS SPI W AND R BY COOQROBOT.
* _Please_ see the comments in MFRC522.h - they give useful hints and background.
* Released into the public domain.
*/
#include "MFRC522.h"
#define MFRC522_MaxPICCs 9
#define MFRC522_MaxError 10
static std::string _TypeNamePICC[MFRC522_MaxPICCs] =
{
"Unknown type",
"PICC compliant with ISO/IEC 14443-4",
"PICC compliant with ISO/IEC 18092 (NFC)",
"MIFARE Mini, 320 bytes",
"MIFARE 1KB",
"MIFARE 4KB",
"MIFARE Ultralight or Ultralight C",
"MIFARE Plus",
"MIFARE TNP3XXX"
};
static std::string _ErrorMessage[MFRC522_MaxError] =
{
"Unknown error",
"Success",
"Error in communication",
"Collision detected",
"Timeout in communication",
"A buffer is not big enough",
"Internal error in the code, should not happen",
"Invalid argument",
"The CRC_A does not match",
"A MIFARE PICC responded with NAK"
};
/////////////////////////////////////////////////////////////////////////////////////
// Functions for setting up the driver
/////////////////////////////////////////////////////////////////////////////////////
/**
* Constructor.
* Prepares the output pins.
*/
MFRC522::MFRC522(PinName mosi,
PinName miso,
PinName sclk,
PinName cs,
PinName reset) : m_SPI(mosi, miso, sclk), m_CS(cs), m_RESET(reset)
{
/* init MFRC522 SPI BUS */
m_SPI.format(8, 0);
m_SPI.frequency(8000000);
/* init MFRC522 SPI_CS pin */
m_CS = 1;
/* init MFRC522 RESET pin */
m_RESET = 1;
} // End constructor
/////////////////////////////////////////////////////////////////////////////////////
// Basic interface functions for communicating with the MFRC522
/////////////////////////////////////////////////////////////////////////////////////
/**
* Writes a byte to the specified register in the MFRC522 chip.
* The interface is described in the datasheet section 8.1.2.
*/
void MFRC522::PCD_WriteRegister(uint8_t reg, uint8_t value)
{
m_CS = 0; /* Select SPI Chip MFRC522 */
// MSB == 0 is for writing. LSB is not used in address. Datasheet section 8.1.2.3.
(void) m_SPI.write(reg & 0x7E);
(void) m_SPI.write(value);
m_CS = 1; /* Release SPI Chip MFRC522 */
} // End PCD_WriteRegister()
/**
* Writes a number of bytes to the specified register in the MFRC522 chip.
* The interface is described in the datasheet section 8.1.2.
*/
void MFRC522::PCD_WriteRegister(uint8_t reg, uint8_t count, uint8_t *values)
{
m_CS = 0; /* Select SPI Chip MFRC522 */
// MSB == 0 is for writing. LSB is not used in address. Datasheet section 8.1.2.3.
(void) m_SPI.write(reg & 0x7E);
for (uint8_t index = 0; index < count; index++)
{
(void) m_SPI.write(values[index]);
}
m_CS = 1; /* Release SPI Chip MFRC522 */
} // End PCD_WriteRegister()
/**
* Reads a byte from the specified register in the MFRC522 chip.
* The interface is described in the datasheet section 8.1.2.
*/
uint8_t MFRC522::PCD_ReadRegister(uint8_t reg)
{
uint8_t value;
m_CS = 0; /* Select SPI Chip MFRC522 */
// MSB == 1 is for reading. LSB is not used in address. Datasheet section 8.1.2.3.
(void) m_SPI.write(0x80 | reg);
value = m_SPI.write(0); // Read the value back. Send 0 to stop reading.
m_CS = 1; /* Release SPI Chip MFRC522 */
return value;
} // End PCD_ReadRegister()
/**
* Reads a number of bytes from the specified register in the MFRC522 chip.
* The interface is described in the datasheet section 8.1.2.
*/
void MFRC522::PCD_ReadRegister(uint8_t reg, uint8_t count, uint8_t *values, uint8_t rxAlign)
{
if (count == 0) { return; }
//Serial.print("Reading "); Serial.print(count); Serial.println(" bytes from register.");
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.
m_CS = 0; /* Select SPI Chip MFRC522 */
count--; // One read is performed outside of the loop
(void) m_SPI.write(address); // Tell MFRC522 which address we want to read
while (index < count)
{
if ((index == 0) && rxAlign) // Only update bit positions rxAlign..7 in values[0]
{
// Create bit mask for bit positions rxAlign..7
uint8_t mask = 0;
for (uint8_t i = rxAlign; i <= 7; i++)
{
mask |= (1 << i);
}
// Read value and tell that we want to read the same address again.
uint8_t value = m_SPI.write(address);
// Apply mask to both current value of values[0] and the new data in value.
values[0] = (values[index] & ~mask) | (value & mask);
}
else
{
// Read value and tell that we want to read the same address again.
values[index] = m_SPI.write(address);
}
index++;
}
values[index] = m_SPI.write(0); // Read the final byte. Send 0 to stop reading.
m_CS = 1; /* Release SPI Chip MFRC522 */
} // End PCD_ReadRegister()
/**
* Sets the bits given in mask in register reg.
*/
void MFRC522::PCD_SetRegisterBitMask(uint8_t reg, uint8_t mask)
{
uint8_t tmp;
tmp = PCD_ReadRegister(reg);
PCD_WriteRegister(reg, tmp | mask); // set bit mask
} // End PCD_SetRegisterBitMask()
/**
* Clears the bits given in mask from register reg.
*/
void MFRC522::PCD_ClearRegisterBitMask(uint8_t reg, uint8_t mask)
{
uint8_t tmp;
tmp = PCD_ReadRegister(reg);
PCD_WriteRegister(reg, tmp & (~mask)); // clear bit mask
} // End PCD_ClearRegisterBitMask()
/**
* Use the CRC coprocessor in the MFRC522 to calculate a CRC_A.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::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_SetRegisterBitMask(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. Each iteration of the while-loop takes 17.73�s.
uint16_t i = 5000;
uint8_t n;
while (1)
{
n = PCD_ReadRegister(DivIrqReg); // DivIrqReg[7..0] bits are: Set2 reserved reserved MfinActIRq reserved CRCIRq reserved reserved
if (n & 0x04)
{
// CRCIRq bit set - calculation done
break;
}
if (--i == 0)
{
// The emergency break. We will eventually terminate on this one after 89ms.
// Communication with the MFRC522 might be down.
return STATUS_TIMEOUT;
}
}
// Stop calculating CRC for new content in the FIFO.
PCD_WriteRegister(CommandReg, PCD_Idle);
// Transfer the result from the registers to the result buffer
result[0] = PCD_ReadRegister(CRCResultRegL);
result[1] = PCD_ReadRegister(CRCResultRegH);
return STATUS_OK;
} // End PCD_CalculateCRC()
/////////////////////////////////////////////////////////////////////////////////////
// Functions for manipulating the MFRC522
/////////////////////////////////////////////////////////////////////////////////////
/**
* Initializes the MFRC522 chip.
*/
void MFRC522::PCD_Init()
{
/* Reset MFRC522 */
m_RESET = 0;
wait_ms(10);
m_RESET = 1;
// Section 8.8.2 in the datasheet says the oscillator start-up time is the start up time of the crystal + 37,74�s. Let us be generous: 50ms.
wait_ms(50);
// 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 25�s.
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)
} // End PCD_Init()
/**
* Performs a soft reset on the MFRC522 chip and waits for it to be ready again.
*/
void MFRC522::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 + 37,74�s. Let us be generous: 50ms.
wait_ms(50);
// Wait for the PowerDown bit in CommandReg to be cleared
while (PCD_ReadRegister(CommandReg) & (1<<4))
{
// PCD still restarting - unlikely after waiting 50ms, but better safe than sorry.
}
} // End PCD_Reset()
/**
* Turns the antenna on by enabling pins TX1 and TX2.
* After a reset these pins disabled.
*/
void MFRC522::PCD_AntennaOn()
{
uint8_t value = PCD_ReadRegister(TxControlReg);
if ((value & 0x03) != 0x03)
{
PCD_WriteRegister(TxControlReg, value | 0x03);
}
} // End PCD_AntennaOn()
/////////////////////////////////////////////////////////////////////////////////////
// Functions for communicating with PICCs
/////////////////////////////////////////////////////////////////////////////////////
/**
* Executes the Transceive command.
* CRC validation can only be done if backData and backLen are specified.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::PCD_TransceiveData(uint8_t *sendData, ///< Pointer to the data to transfer to the FIFO.
uint8_t sendLen, ///< Number of bytes to transfer to the FIFO.
uint8_t *backData, ///< NULL or pointer to buffer if data should be read back after executing the command.
uint8_t *backLen, ///< In: Max number of bytes to write to *backData. Out: The number of bytes returned.
uint8_t *validBits, ///< In/Out: The number of valid bits in the last byte. 0 for 8 valid bits. Default NULL.
uint8_t rxAlign, ///< In: Defines the bit position in backData[0] for the first bit received. Default 0.
bool checkCRC) ///< In: True => The last two bytes of the response is assumed to be a CRC_A that must be validated.
{
uint8_t waitIRq = 0x30; // RxIRq and IdleIRq
return PCD_CommunicateWithPICC(PCD_Transceive, waitIRq, sendData, sendLen, backData, backLen, validBits, rxAlign, checkCRC);
} // End PCD_TransceiveData()
/**
* Transfers data to the MFRC522 FIFO, executes a commend, waits for completion and transfers data back from the FIFO.
* CRC validation can only be done if backData and backLen are specified.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::PCD_CommunicateWithPICC(uint8_t command, ///< The command to execute. One of the PCD_Command enums.
uint8_t waitIRq, ///< The bits in the ComIrqReg register that signals successful completion of the command.
uint8_t *sendData, ///< Pointer to the data to transfer to the FIFO.
uint8_t sendLen, ///< Number of bytes to transfer to the FIFO.
uint8_t *backData, ///< NULL or pointer to buffer if data should be read back after executing the command.
uint8_t *backLen, ///< In: Max number of bytes to write to *backData. Out: The number of bytes returned.
uint8_t *validBits, ///< In/Out: The number of valid bits in the last byte. 0 for 8 valid bits.
uint8_t rxAlign, ///< In: Defines the bit position in backData[0] for the first bit received. Default 0.
bool checkCRC) ///< In: True => The last two bytes of the response is assumed to be a CRC_A that must be validated.
{
uint8_t n, _validBits = 0;
uint32_t i;
// 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_SetRegisterBitMask(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
}
// Wait for the command to complete.
// In PCD_Init() we set the TAuto flag in TModeReg. This means the timer automatically starts when the PCD stops transmitting.
// Each iteration of the do-while-loop takes 17.86�s.
i = 2000;
while (1)
{
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.
break;
}
if (n & 0x01)
{ // Timer interrupt - nothing received in 25ms
return STATUS_TIMEOUT;
}
if (--i == 0)
{ // The emergency break. If all other condions fail we will eventually terminate on this one after 35.7ms. Communication with the MFRC522 might be down.
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;
}
// If the caller wants data back, get it from the MFRC522.
if (backData && backLen)
{
n = PCD_ReadRegister(FIFOLevelReg); // Number of bytes in the FIFO
if (n > *backLen)
{
return STATUS_NO_ROOM;
}
*backLen = n; // Number of bytes 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 byte. If this value is 000b, the whole byte 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 byte 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];
n = PCD_CalculateCRC(&backData[0], *backLen - 2, &controlBuffer[0]);
if (n != STATUS_OK)
{
return n;
}
if ((backData[*backLen - 2] != controlBuffer[0]) || (backData[*backLen - 1] != controlBuffer[1]))
{
return STATUS_CRC_WRONG;
}
}
return STATUS_OK;
} // End PCD_CommunicateWithPICC()
/**
* Transmits a REQuest command, Type A. Invites PICCs in state IDLE to go to READY and prepare for anticollision or selection. 7 bit frame.
* Beware: When two PICCs are in the field at the same time I often get STATUS_TIMEOUT - probably due do bad antenna design.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::PICC_RequestA(uint8_t *bufferATQA, uint8_t *bufferSize)
{
return PICC_REQA_or_WUPA(PICC_CMD_REQA, bufferATQA, bufferSize);
} // End PICC_RequestA()
/**
* Transmits a Wake-UP command, Type A. Invites PICCs in state IDLE and HALT to go to READY(*) and prepare for anticollision or selection. 7 bit frame.
* Beware: When two PICCs are in the field at the same time I often get STATUS_TIMEOUT - probably due do bad antenna design.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::PICC_WakeupA(uint8_t *bufferATQA, uint8_t *bufferSize)
{
return PICC_REQA_or_WUPA(PICC_CMD_WUPA, bufferATQA, bufferSize);
} // End PICC_WakeupA()
/**
* Transmits REQA or WUPA commands.
* Beware: When two PICCs are in the field at the same time I often get STATUS_TIMEOUT - probably due do bad antenna design.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::PICC_REQA_or_WUPA(uint8_t command, uint8_t *bufferATQA, uint8_t *bufferSize)
{
uint8_t validBits;
uint8_t status;
if (bufferATQA == NULL || *bufferSize < 2) { // The ATQA response is 2 bytes 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) byte. 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()
/**
* Transmits SELECT/ANTICOLLISION commands to select a single PICC.
* Before calling this function the PICCs must be placed in the READY(*) state by calling PICC_RequestA() or PICC_WakeupA().
* On success:
* - The chosen PICC is in state ACTIVE(*) and all other PICCs have returned to state IDLE/HALT. (Figure 7 of the ISO/IEC 14443-3 draft.)
* - The UID size and value of the chosen PICC is returned in *uid along with the SAK.
*
* A PICC UID consists of 4, 7 or 10 bytes.
* Only 4 bytes can be specified in a SELECT command, so for the longer UIDs two or three iterations are used:
* UID size Number of UID bytes Cascade levels Example of PICC
* ======== =================== ============== ===============
* single 4 1 MIFARE Classic
* double 7 2 MIFARE Ultralight
* triple 10 3 Not currently in use?
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::PICC_Select(Uid *uid, uint8_t validBits)
{
bool uidComplete;
bool selectDone;
bool useCascadeTag;
uint8_t cascadeLevel = 1;
uint8_t result;
uint8_t count;
uint8_t index;
uint8_t uidIndex; // The first index in uid->uidByte[] that is used in the current Cascade Level.
uint8_t currentLevelKnownBits; // The number of known UID bits in the current Cascade Level.
uint8_t buffer[9]; // The SELECT/ANTICOLLISION commands uses a 7 byte standard frame + 2 bytes CRC_A
uint8_t bufferUsed; // The number of bytes used in the buffer, ie the number of bytes 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 byte.
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 bytes, 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 bytes 2-5
// Byte 7: CRC_A
// Byte 8: CRC_A
// The BCC and CRC_A is only transmitted if we know all the UID bits of the current Cascade Level.
//
// Description of bytes 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 bytes 1 uid0 uid1 uid2 uid3
// 7 bytes 1 CT uid0 uid1 uid2
// 2 uid3 uid4 uid5 uid6
// 10 bytes 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 byte, find out if we need to use the Cascade Tag in byte 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 bytes
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 bytes
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?
if(validBits > (8 * uidIndex))
{
currentLevelKnownBits = validBits - (8 * uidIndex);
}
else
{
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 bytesToCopy = currentLevelKnownBits / 8 + (currentLevelKnownBits % 8 ? 1 : 0); // The number of bytes needed to represent the known bits for this level.
if (bytesToCopy)
{
uint8_t maxBytes = useCascadeTag ? 3 : 4; // Max 4 bytes in each Cascade Level. Only 3 left if we use the Cascade Tag
if (bytesToCopy > maxBytes)
{
bytesToCopy = maxBytes;
}
for (count = 0; count < bytesToCopy; 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 bytes to send and receive.
if (currentLevelKnownBits >= 32) { // All UID bits in this Cascade Level are known. This is a SELECT.
//Serial.print("SELECT: currentLevelKnownBits="); Serial.println(currentLevelKnownBits, DEC);
buffer[1] = 0x70; // NVB - Number of Valid Bits: Seven whole bytes
// Calulate 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 bytes of buffer (BCC and CRC_A - not needed after tx)
responseBuffer = &buffer[6];
responseLength = 3;
}
else { // This is an ANTICOLLISION.
//Serial.print("ANTICOLLISION: currentLevelKnownBits="); Serial.println(currentLevelKnownBits, DEC);
txLastBits = currentLevelKnownBits % 8;
count = currentLevelKnownBits / 8; // Number of whole bytes in the UID part.
index = 2 + count; // Number of whole bytes: 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 seperate 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.
result = PCD_ReadRegister(CollReg); // CollReg[7..0] bits are: ValuesAfterColl reserved CollPosNotValid CollPos[4:0]
if (result & 0x20) { // CollPosNotValid
return STATUS_COLLISION; // Without a valid collision position we cannot continue
}
uint8_t collisionPos = result & 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 - 1) % 8; // The bit to modify
index = 1 + (currentLevelKnownBits / 8) + (count ? 1 : 0); // First byte is index 0.
buffer[index] |= (1 << count);
}
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 bytes from buffer[] to uid->uidByte[]
index = (buffer[2] == PICC_CMD_CT) ? 3 : 2; // source index in buffer[]
bytesToCopy = (buffer[2] == PICC_CMD_CT) ? 3 : 4;
for (count = 0; count < bytesToCopy; count++)
{
uid->uidByte[uidIndex + count] = buffer[index++];
}
// Check response SAK (Select Acknowledge)
if (responseLength != 3 || txLastBits != 0) { // SAK must be exactly 24 bits (1 byte + CRC_A).
return STATUS_ERROR;
}
// Verify CRC_A - do our own calculation and store the control in buffer[2..3] - those bytes 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()
/**
* Instructs a PICC in state ACTIVE(*) to go to state HALT.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::PICC_HaltA()
{
uint8_t 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 an success.
result = PCD_TransceiveData(buffer, sizeof(buffer), NULL, 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
/////////////////////////////////////////////////////////////////////////////////////
/**
* Executes the MFRC522 MFAuthent command.
* This command manages MIFARE authentication to enable a secure communication to any MIFARE Mini, MIFARE 1K and MIFARE 4K card.
* The authentication is described in the MFRC522 datasheet section 10.3.1.9 and http://www.nxp.com/documents/data_sheet/MF1S503x.pdf section 10.1.
* For use with MIFARE Classic PICCs.
* The PICC must be selected - ie in state ACTIVE(*) - before calling this function.
* Remember to call PCD_StopCrypto1() after communicating with the authenticated PICC - otherwise no new communications can start.
*
* All keys are set to FFFFFFFFFFFFh at chip delivery.
*
* @return STATUS_OK on success, STATUS_??? otherwise. Probably STATUS_TIMEOUT if you supply the wrong key.
*/
uint8_t MFRC522::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 bytes
sendData[2+i] = key->keyByte[i];
}
for (uint8_t i = 0; i < 4; i++) { // The first 4 bytes of the UID
sendData[8+i] = uid->uidByte[i];
}
// Start the authentication.
return PCD_CommunicateWithPICC(PCD_MFAuthent, waitIRq, &sendData[0], sizeof(sendData));
} // End PCD_Authenticate()
/**
* Used to exit the PCD from its authenticated state.
* Remember to call this function after communicating with an authenticated PICC - otherwise no new communications can start.
*/
void MFRC522::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()
/**
* Reads 16 bytes (+ 2 bytes CRC_A) from the active PICC.
*
* For MIFARE Classic the sector containing the block must be authenticated before calling this function.
*
* For MIFARE Ultralight only addresses 00h to 0Fh are decoded.
* The MF0ICU1 returns a NAK for higher addresses.
* The MF0ICU1 responds to the READ command by sending 16 bytes starting from the page address defined by the command argument.
* For example; if blockAddr is 03h then pages 03h, 04h, 05h, 06h are returned.
* A roll-back is implemented: If blockAddr is 0Eh, then the contents of pages 0Eh, 0Fh, 00h and 01h are returned.
*
* The buffer must be at least 18 bytes because a CRC_A is also returned.
* Checks the CRC_A before returning STATUS_OK.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::MIFARE_Read(uint8_t blockAddr, uint8_t *buffer, uint8_t *bufferSize)
{
uint8_t result;
// Sanity check
if (buffer == NULL || *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, NULL, 0, true);
} // End MIFARE_Read()
/**
* Writes 16 bytes to the active PICC.
*
* For MIFARE Classic the sector containing the block must be authenticated before calling this function.
*
* For MIFARE Ultralight the opretaion is called "COMPATIBILITY WRITE".
* Even though 16 bytes are transferred to the Ultralight PICC, only the least significant 4 bytes (bytes 0 to 3)
* are written to the specified address. It is recommended to set the remaining bytes 04h to 0Fh to all logic 0.
* *
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::MIFARE_Write(uint8_t blockAddr, uint8_t *buffer, uint8_t bufferSize)
{
uint8_t result;
// Sanity check
if (buffer == NULL || 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()
/**
* Writes a 4 byte page to the active MIFARE Ultralight PICC.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::MIFARE_Ultralight_Write(uint8_t page, uint8_t *buffer, uint8_t bufferSize)
{
uint8_t result;
// Sanity check
if (buffer == NULL || 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()
/**
* MIFARE Decrement subtracts the delta from the value of the addressed block, and stores the result in a volatile memory.
* For MIFARE Classic only. The sector containing the block must be authenticated before calling this function.
* Only for blocks in "value block" mode, ie with access bits [C1 C2 C3] = [110] or [001].
* Use MIFARE_Transfer() to store the result in a block.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::MIFARE_Decrement(uint8_t blockAddr, uint32_t delta)
{
return MIFARE_TwoStepHelper(PICC_CMD_MF_DECREMENT, blockAddr, delta);
} // End MIFARE_Decrement()
/**
* MIFARE Increment adds the delta to the value of the addressed block, and stores the result in a volatile memory.
* For MIFARE Classic only. The sector containing the block must be authenticated before calling this function.
* Only for blocks in "value block" mode, ie with access bits [C1 C2 C3] = [110] or [001].
* Use MIFARE_Transfer() to store the result in a block.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::MIFARE_Increment(uint8_t blockAddr, uint32_t delta)
{
return MIFARE_TwoStepHelper(PICC_CMD_MF_INCREMENT, blockAddr, delta);
} // End MIFARE_Increment()
/**
* MIFARE Restore copies the value of the addressed block into a volatile memory.
* For MIFARE Classic only. The sector containing the block must be authenticated before calling this function.
* Only for blocks in "value block" mode, ie with access bits [C1 C2 C3] = [110] or [001].
* Use MIFARE_Transfer() to store the result in a block.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::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()
/**
* Helper function for the two-step MIFARE Classic protocol operations Decrement, Increment and Restore.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::MIFARE_TwoStepHelper(uint8_t command, uint8_t blockAddr, uint32_t data)
{
uint8_t result;
uint8_t cmdBuffer[2]; // We only need room for 2 bytes.
// 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()
/**
* MIFARE Transfer writes the value stored in the volatile memory into one MIFARE Classic block.
* For MIFARE Classic only. The sector containing the block must be authenticated before calling this function.
* Only for blocks in "value block" mode, ie with access bits [C1 C2 C3] = [110] or [001].
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::MIFARE_Transfer(uint8_t blockAddr)
{
uint8_t result;
uint8_t cmdBuffer[2]; // We only need room for 2 bytes.
// 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()
/////////////////////////////////////////////////////////////////////////////////////
// Support functions
/////////////////////////////////////////////////////////////////////////////////////
/**
* Wrapper for MIFARE protocol communication.
* Adds CRC_A, executes the Transceive command and checks that the response is MF_ACK or a timeout.
*
* @return STATUS_OK on success, STATUS_??? otherwise.
*/
uint8_t MFRC522::PCD_MIFARE_Transceive(uint8_t *sendData, uint8_t sendLen, bool acceptTimeout)
{
uint8_t result;
uint8_t cmdBuffer[18]; // We need room for 16 bytes data and 2 bytes CRC_A.
// Sanity check
if (sendData == NULL || 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()
/**
* Translates the SAK (Select Acknowledge) to a PICC type.
*
* @return PICC_Type
*/
uint8_t MFRC522::PICC_GetType(uint8_t sak)
{
uint8_t retType = PICC_TYPE_UNKNOWN;
if (sak & 0x04) // UID not complete
{
retType = PICC_TYPE_NOT_COMPLETE;
}
else
{
switch (sak)
{
case 0x09: retType = PICC_TYPE_MIFARE_MINI; break;
case 0x08: retType = PICC_TYPE_MIFARE_1K; break;
case 0x18: retType = PICC_TYPE_MIFARE_4K; break;
case 0x00: retType = PICC_TYPE_MIFARE_UL; break;
case 0x10:
case 0x11: retType = PICC_TYPE_MIFARE_PLUS; break;
case 0x01: retType = PICC_TYPE_TNP3XXX; break;
default:
if (sak & 0x20)
{
retType = PICC_TYPE_ISO_14443_4;
}
else if (sak & 0x40)
{
retType = PICC_TYPE_ISO_18092;
}
break;
}
}
return (retType);
} // End PICC_GetType()
/**
* Returns a string pointer to the PICC type name.
*
*/
std::string MFRC522::PICC_GetTypeName(uint8_t piccType)
{
if(piccType == PICC_TYPE_NOT_COMPLETE)
{
return ("SAK indicates UID is not complete.");
}
return(_TypeNamePICC[piccType]);
} // End PICC_GetTypeName()
/**
* Returns a string pointer to a status code name.
*
*/
std::string MFRC522::GetStatusCodeName(uint8_t code)
{
return(_ErrorMessage[code]);
} // End GetStatusCodeName()
/**
* Calculates the bit pattern needed for the specified access bits. In the [C1 C2 C3] tupples C1 is MSB (=4) and C3 is LSB (=1).
*/
void MFRC522::MIFARE_SetAccessBits(uint8_t *accessBitBuffer, ///< Pointer to byte 6, 7 and 8 in the sector trailer. Bytes [0..2] will be set.
uint8_t g0, ///< Access bits [C1 C2 C3] for block 0 (for sectors 0-31) or blocks 0-4 (for sectors 32-39)
uint8_t g1, ///< Access bits C1 C2 C3] for block 1 (for sectors 0-31) or blocks 5-9 (for sectors 32-39)
uint8_t g2, ///< Access bits C1 C2 C3] for block 2 (for sectors 0-31) or blocks 10-14 (for sectors 32-39)
uint8_t g3) ///< Access bits C1 C2 C3] for the sector trailer, block 3 (for sectors 0-31) or block 15 (for sectors 32-39)
{
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()
/////////////////////////////////////////////////////////////////////////////////////
// Convenience functions - does not add extra functionality
/////////////////////////////////////////////////////////////////////////////////////
/**
* Returns true if a PICC responds to PICC_CMD_REQA.
* Only "new" cards in state IDLE are invited. Sleeping cards in state HALT are ignored.
*
* @return bool
*/
bool MFRC522::PICC_IsNewCardPresent()
{
uint8_t bufferATQA[2];
uint8_t bufferSize = sizeof(bufferATQA);
uint8_t result = PICC_RequestA(bufferATQA, &bufferSize);
return (result == STATUS_OK || result == STATUS_COLLISION);
} // End PICC_IsNewCardPresent()
/**
* Simple wrapper around PICC_Select.
* Returns true if a UID could be read.
* Remember to call PICC_IsNewCardPresent(), PICC_RequestA() or PICC_WakeupA() first.
* The read UID is available in the class variable uid.
*
* @return bool
*/
bool MFRC522::PICC_ReadCardSerial()
{
uint8_t result = PICC_Select(&uid);
return (result == STATUS_OK);
} // End PICC_ReadCardSerial()