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#include "maindefs.h"

#include "nfc.h"

#include "i2c.h"

#include <string.h>

#include <delays.h>

static NFC_DATA nfc_data;

// Const value arrays for comparison use

static char pn532response_firmwarevers[] = {0x01, 0x00, 0x00, 0xFF, 0x06, 0xFA, 0xD5, 0x03};

static char pn532ack[] = {0x01, 0x00, 0x00, 0xFF, 0x00, 0xFF, 0x00};

void NFC_Init() {

    TRISCbits.TRISC1 = 1; // IRQ Pin is RC5

    TRISCbits.TRISC2 = 0; // Reset Pin is RC2

    // Reset the PN532

    LATCbits.LATC2 = 1;

    LATCbits.LATC2 = 0;

    Delay10TCYx(1);

    LATCbits.LATC2 = 1;

}

// Configures the SAM (Secure Access Module)

unsigned char NFC_SAMConfig() {

    nfc_data.packetbuffer[0] = PN532_COMMAND_SAMCONFIGURATION;

    nfc_data.packetbuffer[1] = 0x01; // Normal mode

    nfc_data.packetbuffer[2] = 0x14; // Timeout 50ms * 20 = 1s

    nfc_data.packetbuffer[3] = 0x01; // Use IRQ pin

    if (!NFC_sendCommandCheckAck(nfc_data.packetbuffer, 4))

        return 0;

    NFC_I2C_Read_Data(nfc_data.packetbuffer, 8);

    return (nfc_data.packetbuffer[7] == 0x15);

}

// Checks the firmware version of the PN5xx chip

NFC_FIRMWARE_VERSION NFC_getFirmwareVersion(void) {

    NFC_FIRMWARE_VERSION response = {0, 0, 0, 0};

    // Create and send command

    nfc_data.packetbuffer[0] = PN532_COMMAND_GETFIRMWAREVERSION;

    if (!NFC_sendCommandCheckAck(nfc_data.packetbuffer, 1))

        return response;

    // Read back data from the PN532

    NFC_I2C_Read_Data(nfc_data.packetbuffer, 12);

    // Compare and check returned values

    if (strncmp((char *) nfc_data.packetbuffer, (char *) pn532response_firmwarevers, 8) != 0)

        return response;

    // Save and return info

    response.IC = nfc_data.packetbuffer[8];

    response.Ver = nfc_data.packetbuffer[9];

    response.Rev = nfc_data.packetbuffer[10];

    response.Support = nfc_data.packetbuffer[11];

    return response;

}

// Sends a command and waits a specified period for the ACK

unsigned char NFC_sendCommandCheckAck(unsigned char *cmd, unsigned char cmdlen) {

    unsigned int timer = 0;

    // Write the command

    NFC_I2C_Write_Cmd(cmd, cmdlen);

    // Wait for chip to be ready

    while (NFC_I2C_Read_Status() != PN532_I2C_READY) {

        if (PN532_TIMEOUT != 0) {

            timer += 1;

            if (timer > PN532_TIMEOUT)

                return 0;

        }

        Delay10TCYx(1);

    }

    // Check ACK

    if (!NFC_I2C_Read_ACK()) {

        return 0;

    }

    return 1;

}

// Passive polling, waits for an ISO14443A target to enter the field

unsigned char NFC_readPassiveTargetID(NFC_TargetDataMiFare *cardData) {

    nfc_data.packetbuffer[0] = PN532_COMMAND_INLISTPASSIVETARGET;

    nfc_data.packetbuffer[1] = 2; // Max 2 cards at once

    nfc_data.packetbuffer[2] = PN532_MIFARE_ISO14443A;  // Mifare only

    if (!NFC_sendCommandCheckAck(nfc_data.packetbuffer, 3))

        return 0;

    // Wait for IRQ line

    while (NFC_I2C_Read_Status() != PN532_I2C_READY);

    NFC_I2C_Read_Data(nfc_data.packetbuffer, 35);

    /* InListPassiveTarget response should be in the following format:

     * Byte         Description

     * ----------   ------------------

     * b0           Data ACK

     * b1..7        Frame header and preamble

     * b8           Tags found

     * b9..N        NFC_TargetDataMiFare[2]

     * bN+1..N+2    Checksum + postamble

     */

    // Check # of tags found

    if (!nfc_data.packetbuffer[8])

        return 0;

    // Save data from first card

    if (nfc_data.packetbuffer[13] == 4) {

        memcpy((char *)&cardData[0], (const char *)&nfc_data.packetbuffer[9], 9);

    } else {

        memcpy((char *)&cardData[0], (const char *)&nfc_data.packetbuffer[9], 12);

    }

    // Save data from second card

    if (nfc_data.packetbuffer[8] == 2) {

        // Offset will vary depending on length of first card

        if (nfc_data.packetbuffer[13] == 4) {

            if (nfc_data.packetbuffer[22] == 4) {

                memcpy((char *)&cardData[1], (const char *)&nfc_data.packetbuffer[18], 9);

            } else {

                memcpy((char *)&cardData[1], (const char *)&nfc_data.packetbuffer[18], 12);

            }

        } else { // Length of first UID is 7

            if (nfc_data.packetbuffer[25] == 4) {

                memcpy((char *)&cardData[1], (const char *)&nfc_data.packetbuffer[21], 9);

            } else {

                memcpy((char *)&cardData[1], (const char *)&nfc_data.packetbuffer[21], 12);

            }

        }

    }

    // Return the number of cards detected

    return nfc_data.packetbuffer[8];

}

// Active polling, returns number of cards in the field

unsigned char NFC_pollTargets(unsigned char number, unsigned char period, NFC_TargetDataMiFare *cardData) {

    nfc_data.packetbuffer[0] = PN532_COMMAND_INAUTOPOLL;

    nfc_data.packetbuffer[1] = number; // Number of polling

    nfc_data.packetbuffer[2] = period; // Polling period in units of 150ms

    nfc_data.packetbuffer[3] = 0x10; // Check for Mifare cards only

    if (!NFC_sendCommandCheckAck(nfc_data.packetbuffer, 4))

        return 0;

    // Wait for IRQ line

    while (NFC_I2C_Read_Status() != PN532_I2C_READY);

    NFC_I2C_Read_Data(nfc_data.packetbuffer, 37);

    /* InAutoPoll response should be in the following format:

     * Byte         Description

     * ----------   ------------------

     * b0           Data ACK

     * b1..7        Frame header and preamble

     * b6           Tags found

     * b7           Polled target type (should be 0x10 Mifare)

     * b8           TargetData length (1/2)

     * b9..N        NFC_TargetDataMiFare[1/2]

     * bN+1..N+2    Checksum + postamble

     */

    // Check # of tags found

    if (!nfc_data.packetbuffer[8])

        return 0;

        // Save data from first card

    if (nfc_data.packetbuffer[15] == 4) {

        memcpy((char *)&cardData[0], (const char *)&nfc_data.packetbuffer[11], 9);

    } else {

        memcpy((char *)&cardData[0], (const char *)&nfc_data.packetbuffer[11], 12);

    }

    // Save data from second card

    if (nfc_data.packetbuffer[8] == 2) {

        // Offset will vary depending on length of first card

        if (nfc_data.packetbuffer[15] == 4) {

            if (nfc_data.packetbuffer[26] == 4) {

                memcpy((char *)&cardData[1], (const char *)&nfc_data.packetbuffer[22], 9);

            } else {

                memcpy((char *)&cardData[1], (const char *)&nfc_data.packetbuffer[22], 12);

            }

        } else {

            if (nfc_data.packetbuffer[29] == 4) {

                memcpy((char *)&cardData[1], (const char *)&nfc_data.packetbuffer[25], 9);

            } else {

                memcpy((char *)&cardData[1], (const char *)&nfc_data.packetbuffer[25], 12);

            }

        }

    }

    // Return the number of cards detected

    return nfc_data.packetbuffer[8];

}

// Indicates whether the specified block number is the first block

//      in the sector (block 0 relative to the current sector)

unsigned char NFC_mifareclassic_IsFirstBlock(unsigned long uiBlock) {

    // Test if we are in the small or big sectors

    if (uiBlock < 128)

        return ((uiBlock) % 4 == 0);

    else

        return ((uiBlock) % 16 == 0);

}

// Indicates whether the specified block number is the sector trailer

unsigned char NFC_mifareclassic_IsTrailerBlock(unsigned long uiBlock) {

    // Test if we are in the small or big sectors

    if (uiBlock < 128)

        return ((uiBlock + 1) % 4 == 0);

    else

        return ((uiBlock + 1) % 16 == 0);

}

// Tries to authenticate a block of memory on a MIFARE card using the INDATAEXCHANGE command

unsigned char NFC_mifareclassic_AuthenticateBlock(unsigned char *uid, unsigned char uidLen, unsigned long blockNumber, unsigned char keyNumber, unsigned char *keyData) {

    // See section 7.3.8 of the PN532 User Manual

    // blockNumber = The block number to authenticate.  (0..63 for 1KB cards, and 0..255 for 4KB cards)\

    // keyNumber = Which key type to use during authentication (0 = MIFARE_CMD_AUTH_A, 1 = MIFARE_CMD_AUTH_B)

    // keyData = Pointer to a byte array containing the 6 byte key value

    unsigned char i;

    // Assemble frame data

    nfc_data.packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE; /* Data Exchange Header */

    nfc_data.packetbuffer[1] = 1; /* Max card numbers */

    nfc_data.packetbuffer[2] = (keyNumber) ? MIFARE_CMD_AUTH_A : MIFARE_CMD_AUTH_B;

    nfc_data.packetbuffer[3] = blockNumber; /* Block Number (1K = 0..63, 4K = 0..255 */

    for (i = 0; i < 6; i++) {

        nfc_data.packetbuffer[4 + i] = keyData[i];

    }

    for (i = 0; i < uidLen; i++) {

        nfc_data.packetbuffer[10 + i] = uid[i];

    }

    // Send frame and check for ACK

    if (!NFC_sendCommandCheckAck(nfc_data.packetbuffer, 10 + uidLen))

        return 0;

    // Read response from PN532

    NFC_I2C_Read_Data(nfc_data.packetbuffer, 12);

    return 1;

}

// Tries to read an entire 16-byte data block at the specified block address

unsigned char NFC_mifareclassic_ReadDataBlock(unsigned char blockNumber, unsigned char *data) {

    unsigned char i;

    // Assemble frame data

    nfc_data.packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;

    nfc_data.packetbuffer[1] = 1; /* Card number */

    nfc_data.packetbuffer[2] = MIFARE_CMD_READ; /* Mifare Read command = 0x30 */

    nfc_data.packetbuffer[3] = blockNumber; /* Block Number (0..63 for 1K, 0..255 for 4K) */

    // Send frame and check for ACK

    if (!NFC_sendCommandCheckAck(nfc_data.packetbuffer, 4))

        return 0;

    // Read reponse

    NFC_I2C_Read_Data(nfc_data.packetbuffer, 26);

    // If byte 9 isnt 0x00 we probably have and error

    if (nfc_data.packetbuffer[8] != 0x00) {

        return 0;

    }

    // Copy the 16 data bytes into the data buffer

    // Block contents starts at byte 10 of a valid response

    for (i = 0; i < 16; i++) {

        data[i] = nfc_data.packetbuffer[9 + i];

    }

    return 1;

}

// Tries to write an entire 16-byte data block at the specified block address

unsigned char NFC_mifareclassic_WriteDataBlock(unsigned char blockNumber, unsigned char *data) {

    unsigned char i;

    // Assemble frame data

    nfc_data.packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;

    nfc_data.packetbuffer[1] = 1; /* Card number */

    nfc_data.packetbuffer[2] = MIFARE_CMD_WRITE; /* Mifare Write command = 0xA0 */

    nfc_data.packetbuffer[3] = blockNumber; /* Block Number (0..63 for 1K, 0..255 for 4K) */

    for (i = 0; i < 16; i++) { /* Data Payload */

        nfc_data.packetbuffer[4 + i] = data[i];

    }

    // Send frame and check for ACK

    if (!NFC_sendCommandCheckAck(nfc_data.packetbuffer, 20))

        return 0;

    // Read response

    NFC_I2C_Read_Data(nfc_data.packetbuffer, 26);

    return 1;

}

// Formats a Mifare Classic card to store NDEF Records

unsigned char NFC_mifareclassic_FormatNDEF(void) {

    unsigned char sectorbuffer1[16] = {0x14, 0x01, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1};

    unsigned char sectorbuffer2[16] = {0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1};

    unsigned char sectorbuffer3[16] = {0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0x78, 0x77, 0x88, 0xC1, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};

    // Write blocks 1 and 2

    if (!NFC_mifareclassic_WriteDataBlock(1, sectorbuffer1))

        return 0;

    if (!NFC_mifareclassic_WriteDataBlock(2, sectorbuffer2))

        return 0;

    // Write key A and access rights

    if (!NFC_mifareclassic_WriteDataBlock(3, sectorbuffer3))

        return 0;

    return 1;

}

// Writes an NDEF URI Record to the specified sector (1..15)

/* Note that this function assumes that the Mifare Classic card is

    already formatted to work as an "NFC Forum Tag" and uses a MAD1

    file system.  You can use the NXP TagWriter app on Android to

    properly format cards for this. */

unsigned char NFC_mifareclassic_WriteNDEFURI(unsigned char sectorNumber, unsigned char uriIdentifier, const char * url) {

    // uriIdentifier = The uri identifier code (0 = none, 0x01 = "http://www.", etc.)

    // url = The uri text to write (max 38 characters)

    // Figure out how long the string is

    unsigned char len = strlen(url);

    unsigned char sectorbuffer1[16] = {0x00, 0x00, 0x03, len + 5, 0xD1, 0x01, len + 1, 0x55, uriIdentifier, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

    unsigned char sectorbuffer2[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

    unsigned char sectorbuffer3[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

    unsigned char sectorbuffer4[16] = {0xD3, 0xF7, 0xD3, 0xF7, 0xD3, 0xF7, 0x7F, 0x07, 0x88, 0x40, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};

    // Make sure we're within a 1K limit for the sector number

    if ((sectorNumber < 1) || (sectorNumber > 15))

        return 0;

    // Make sure the URI payload is between 1 and 38 chars

    if ((len < 1) || (len > 38))

        return 0;

    if (len <= 6) {

        // Unlikely we'll get a url this short, but why not ...

        memcpy(sectorbuffer1 + 9, url, len);

        sectorbuffer1[len + 9] = 0xFE;

    } else if (len == 7) {

        // 0xFE needs to be wrapped around to next block

        memcpy(sectorbuffer1 + 9, url, len);

        sectorbuffer2[0] = 0xFE;

    } else if ((len > 7) || (len <= 22)) {

        // Url fits in two blocks

        memcpy(sectorbuffer1 + 9, url, 7);

        memcpy(sectorbuffer2, url + 7, len - 7);

        sectorbuffer2[len - 7] = 0xFE;

    } else if (len == 23) {

        // 0xFE needs to be wrapped around to final block

        memcpy(sectorbuffer1 + 9, url, 7);

        memcpy(sectorbuffer2, url + 7, len - 7);

        sectorbuffer3[0] = 0xFE;

    } else {

        // Url fits in three blocks

        memcpy(sectorbuffer1 + 9, url, 7);

        memcpy(sectorbuffer2, url + 7, 16);

        memcpy(sectorbuffer3, url + 23, len - 24);

        sectorbuffer3[len - 22] = 0xFE;

    }

    // Now write all three blocks back to the card

    if (!(NFC_mifareclassic_WriteDataBlock(sectorNumber * 4, sectorbuffer1)))

        return 0;

    if (!(NFC_mifareclassic_WriteDataBlock((sectorNumber * 4) + 1, sectorbuffer2)))

        return 0;

    if (!(NFC_mifareclassic_WriteDataBlock((sectorNumber * 4) + 2, sectorbuffer3)))

        return 0;

    if (!(NFC_mifareclassic_WriteDataBlock((sectorNumber * 4) + 3, sectorbuffer4)))

        return 0;

    return 1;

}

// Reads and checks for the ACK signal

unsigned char NFC_I2C_Read_ACK() {

    unsigned char buffer[7];

    // Check ACK

    NFC_I2C_Read_Data(buffer, 6);

    // Return if the 7 bytes matches the ACK pattern

    return (strncmp((char *) buffer, (char *) pn532ack, 7) == 0);

}

// Checks the IRQ pin to know if the PN532 is ready

unsigned char NFC_I2C_Read_Status() {

    if (PORTCbits.RC1 == 1) {

        return PN532_I2C_BUSY;

    } else {

        return PN532_I2C_READY;

    }

}

// Reads n bytes of data from the PN532 via I2C

void NFC_I2C_Read_Data(unsigned char *buffer, unsigned char length) {

    unsigned char result;

    // Wait for IRQ to go low

    while (NFC_I2C_Read_Status() != PN532_I2C_READY);

    // Read bytes from PN532 into buffer

    I2C_Master_Recv(PN532_I2C_ADDRESS, length + 2);

    result = I2C_Get_Status();

    while (!result) {

        result = I2C_Get_Status();

    }

    I2C_Read_Buffer((char *) buffer);

    /* Remaining packet byte layout is as follows:

     Byte       Description

     -----      ----------------------

     * 0        Data ready ACK

     * 1        Preamble (0x00)

     * 2-3      Start code (0x00,0xFF)

     * 4        Length (TFI to N)

     * 5        Length Checksum (Length + LCS = 0x00)

     * 6        TFI (Frame identifier)

     *              0xD4 - Host to PN532

     *              0xD5 - PN532 to Host

     * 7-N      Data (Length - 1 bytes)

     * N+1      Data checksum (TFI + Data~N + DCS = 0x00)

     * N+2      Postamble (0x00)              */

}

// Writes a command to the PN532, automatically inserting the preamble and required frame details (checksum, len, etc.)

void NFC_I2C_Write_Cmd(unsigned char* cmd, unsigned char cmdlen) {

    int i;

    unsigned char checksum;

    unsigned char buffer[PN532_PACKBUFFSIZ + 8];

    unsigned char buffer_ind = 6;

    cmdlen++;

    checksum = PN532_PREAMBLE + PN532_PREAMBLE + PN532_STARTCODE2 + PN532_HOSTTOPN532;

    // Fill out required frame fields

    buffer[0] = PN532_PREAMBLE;

    buffer[1] = PN532_PREAMBLE;

    buffer[2] = PN532_STARTCODE2;

    buffer[3] = cmdlen;

    buffer[4] = ~cmdlen + 1;

    buffer[5] = PN532_HOSTTOPN532;

    // Copy cmd to be sent

    for (i = 0; i < cmdlen - 1; i++) {

        checksum += cmd[i];

        buffer[buffer_ind] = cmd[i];

        buffer_ind++;

    }

    buffer[buffer_ind] = ~checksum;

    buffer_ind++;

    buffer[buffer_ind] = PN532_POSTAMBLE;

    buffer_ind++;

    I2C_Master_Send(PN532_I2C_ADDRESS, buffer_ind, buffer);

}