/**************************************************************************/
  /*!
      @file     PN532.cpp
      @author   Adafruit Industries & Seeed Studio
      @license  BSD
  */
  /**************************************************************************/
  
  #include "Arduino.h"
  #include "PN532.h"
  #include "PN532_debug.h"
  #include <string.h>
  
  #define HAL(func)   (_interface->func)
  
  void send_serial(unsigned char);
  
  PN532::PN532(PN532Interface &interface)
  {
      _interface = &interface;
  }
  
  /**************************************************************************/
  /*!
      @brief  Setups the HW
  */
  /**************************************************************************/
  void PN532::begin()
  {
  	send_serial('A');
      HAL(begin)();
  	send_serial('B');
      HAL(wakeup)();
  	send_serial('C');
  }
  
  /**************************************************************************/
  /*!
      @brief  Prints a hexadecimal value in plain characters
  
      @param  data      Pointer to the uint8_t data
      @param  numBytes  Data length in bytes
  */
  /**************************************************************************/
  void PN532::PrintHex(const uint8_t *data, const uint32_t numBytes)
  {
  #ifdef ARDUINO
      for (uint8_t i = 0; i < numBytes; i++) {
          if (data[i] < 0x10) {
              Serial.print(" 0");
          } else {
              Serial.print(' ');
          }
          Serial.print(data[i], HEX);
      }
      Serial.println("");
  #else
      for (uint8_t i = 0; i < numBytes; i++) {
          printf(" %2X", data[i]);
      }
      printf("\n");
  #endif
  }
  
  /**************************************************************************/
  /*!
      @brief  Prints a hexadecimal value in plain characters, along with
              the char equivalents in the following format
  
              00 00 00 00 00 00  ......
  
      @param  data      Pointer to the data
      @param  numBytes  Data length in bytes
  */
  /**************************************************************************/
  void PN532::PrintHexChar(const uint8_t *data, const uint32_t numBytes)
  {
  #ifdef ARDUINO
      for (uint8_t i = 0; i < numBytes; i++) {
          if (data[i] < 0x10) {
              Serial.print(" 0");
          } else {
              Serial.print(' ');
          }
          Serial.print(data[i], HEX);
      }
      Serial.print("    ");
      for (uint8_t i = 0; i < numBytes; i++) {
          char c = data[i];
          if (c <= 0x1f || c > 0x7f) {
              Serial.print('.');
          } else {
              Serial.print(c);
          }
      }
      Serial.println("");
  #else
      for (uint8_t i = 0; i < numBytes; i++) {
          printf(" %2X", data[i]);
      }
      printf("    ");
      for (uint8_t i = 0; i < numBytes; i++) {
          char c = data[i];
          if (c <= 0x1f || c > 0x7f) {
              printf(".");
          } else {
              printf("%c", c);
          }
          printf("\n");
      }
  #endif
  }
  
  /**************************************************************************/
  /*!
      @brief  Checks the firmware version of the PN5xx chip
  
      @returns  The chip's firmware version and ID
  */
  /**************************************************************************/
  uint32_t PN532::getFirmwareVersion(void)
  {
      uint32_t response;
  
      pn532_packetbuffer[0] = PN532_COMMAND_GETFIRMWAREVERSION;
  
      if (HAL(writeCommand)(pn532_packetbuffer, 1)) {
          return 0;
      }
  
      // read data packet
      int16_t status = HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer));
      if (0 > status) {
          return 0;
      }
  
      response = pn532_packetbuffer[0];
      response <<= 8;
      response |= pn532_packetbuffer[1];
      response <<= 8;
      response |= pn532_packetbuffer[2];
      response <<= 8;
      response |= pn532_packetbuffer[3];
  
      return response;
  }
  
  
  /**************************************************************************/
  /*!
      Writes an 8-bit value that sets the state of the PN532's GPIO pins
  
      @warning This function is provided exclusively for board testing and
               is dangerous since it will throw an error if any pin other
               than the ones marked "Can be used as GPIO" are modified!  All
               pins that can not be used as GPIO should ALWAYS be left high
               (value = 1) or the system will become unstable and a HW reset
               will be required to recover the PN532.
  
               pinState[0]  = P30     Can be used as GPIO
               pinState[1]  = P31     Can be used as GPIO
               pinState[2]  = P32     *** RESERVED (Must be 1!) ***
               pinState[3]  = P33     Can be used as GPIO
               pinState[4]  = P34     *** RESERVED (Must be 1!) ***
               pinState[5]  = P35     Can be used as GPIO
  
      @returns 1 if everything executed properly, 0 for an error
  */
  /**************************************************************************/
  bool PN532::writeGPIO(uint8_t pinstate)
  {
      // Make sure pinstate does not try to toggle P32 or P34
      pinstate |= (1 << PN532_GPIO_P32) | (1 << PN532_GPIO_P34);
  
      // Fill command buffer
      pn532_packetbuffer[0] = PN532_COMMAND_WRITEGPIO;
      pn532_packetbuffer[1] = PN532_GPIO_VALIDATIONBIT | pinstate;  // P3 Pins
      pn532_packetbuffer[2] = 0x00;    // P7 GPIO Pins (not used ... taken by I2C)
  
      DMSG("Writing P3 GPIO: ");
      DMSG_HEX(pn532_packetbuffer[1]);
      DMSG("\n");
  
      // Send the WRITEGPIO command (0x0E)
      if (HAL(writeCommand)(pn532_packetbuffer, 3))
          return 0;
  
      return (0 < HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer)));
  }
  
  /**************************************************************************/
  /*!
      Reads the state of the PN532's GPIO pins
  
      @returns An 8-bit value containing the pin state where:
  
               pinState[0]  = P30
               pinState[1]  = P31
               pinState[2]  = P32
               pinState[3]  = P33
               pinState[4]  = P34
               pinState[5]  = P35
  */
  /**************************************************************************/
  uint8_t PN532::readGPIO(void)
  {
      pn532_packetbuffer[0] = PN532_COMMAND_READGPIO;
  
      // Send the READGPIO command (0x0C)
      if (HAL(writeCommand)(pn532_packetbuffer, 1))
          return 0x0;
  
      HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer));
  
      /* READGPIO response without prefix and suffix should be in the following format:
  
        byte            Description
        -------------   ------------------------------------------
        b0              P3 GPIO Pins
        b1              P7 GPIO Pins (not used ... taken by I2C)
        b2              Interface Mode Pins (not used ... bus select pins)
      */
  
  
      DMSG("P3 GPIO: "); DMSG_HEX(pn532_packetbuffer[7]);
      DMSG("P7 GPIO: "); DMSG_HEX(pn532_packetbuffer[8]);
      DMSG("I0I1 GPIO: "); DMSG_HEX(pn532_packetbuffer[9]);
      DMSG("\n");
  
      return pn532_packetbuffer[0];
  }
  
  /**************************************************************************/
  /*!
      @brief  Configures the SAM (Secure Access Module)
  */
  /**************************************************************************/
  bool PN532::SAMConfig(void)
  {
      pn532_packetbuffer[0] = PN532_COMMAND_SAMCONFIGURATION;
      pn532_packetbuffer[1] = 0x01; // normal mode;
      pn532_packetbuffer[2] = 0x14; // timeout 50ms * 20 = 1 second
      pn532_packetbuffer[3] = 0x01; // use IRQ pin!
  
      DMSG("SAMConfig\n");
  
      if (HAL(writeCommand)(pn532_packetbuffer, 4))
          return false;
  
      return (0 < HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer)));
  }
  
  /**************************************************************************/
  /*!
      Sets the MxRtyPassiveActivation uint8_t of the RFConfiguration register
  
      @param  maxRetries    0xFF to wait forever, 0x00..0xFE to timeout
                            after mxRetries
  
      @returns 1 if everything executed properly, 0 for an error
  */
  /**************************************************************************/
  bool PN532::setPassiveActivationRetries(uint8_t maxRetries)
  {
      pn532_packetbuffer[0] = PN532_COMMAND_RFCONFIGURATION;
      pn532_packetbuffer[1] = 5;    // Config item 5 (MaxRetries)
      pn532_packetbuffer[2] = 0xFF; // MxRtyATR (default = 0xFF)
      pn532_packetbuffer[3] = 0x01; // MxRtyPSL (default = 0x01)
      pn532_packetbuffer[4] = maxRetries;
  
      if (HAL(writeCommand)(pn532_packetbuffer, 5))
          return 0x0;  // no ACK
  
      return (0 < HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer)));
  }
  
  /***** ISO14443A Commands ******/
  
  /**************************************************************************/
  /*!
      Waits for an ISO14443A target to enter the field
  
      @param  cardBaudRate  Baud rate of the card
      @param  uid           Pointer to the array that will be populated
                            with the card's UID (up to 7 bytes)
      @param  uidLength     Pointer to the variable that will hold the
                            length of the card's UID.
      @param  timeout       The number of tries before timing out
      @param  inlist        If set to true, the card will be inlisted
  
      @returns 1 if everything executed properly, 0 for an error
  */
  /**************************************************************************/
  bool PN532::readPassiveTargetID(uint8_t cardbaudrate, uint8_t *uid, uint8_t *uidLength, uint16_t timeout, bool inlist)
  {
      pn532_packetbuffer[0] = PN532_COMMAND_INLISTPASSIVETARGET;
      pn532_packetbuffer[1] = 1;  // max 1 cards at once (we can set this to 2 later)
      pn532_packetbuffer[2] = cardbaudrate;
  
      if (HAL(writeCommand)(pn532_packetbuffer, 3)) {
          return 0x0;  // command failed
      }
  
      // read data packet
      if (HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer), timeout) < 0) {
          return 0x0;
      }
  
      // check some basic stuff
      /* ISO14443A card response should be in the following format:
  
        byte            Description
        -------------   ------------------------------------------
        b0              Tags Found
        b1              Tag Number (only one used in this example)
        b2..3           SENS_RES
        b4              SEL_RES
        b5              NFCID Length
        b6..NFCIDLen    NFCID
      */
  
      if (pn532_packetbuffer[0] != 1)
          return 0;
  
      uint16_t sens_res = pn532_packetbuffer[2];
      sens_res <<= 8;
      sens_res |= pn532_packetbuffer[3];
  
      DMSG("ATQA: 0x");  DMSG_HEX(sens_res);
      DMSG("SAK: 0x");  DMSG_HEX(pn532_packetbuffer[4]);
      DMSG("\n");
  
      /* Card appears to be Mifare Classic */
      *uidLength = pn532_packetbuffer[5];
  
      for (uint8_t i = 0; i < pn532_packetbuffer[5]; i++) {
          uid[i] = pn532_packetbuffer[6 + i];
      }
  
      if (inlist) {
          inListedTag = pn532_packetbuffer[1];
      }
  
      return 1;
  }
  
  
  /***** Mifare Classic Functions ******/
  
  /**************************************************************************/
  /*!
        Indicates whether the specified block number is the first block
        in the sector (block 0 relative to the current sector)
  */
  /**************************************************************************/
  bool PN532::mifareclassic_IsFirstBlock (uint32_t 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
  */
  /**************************************************************************/
  bool PN532::mifareclassic_IsTrailerBlock (uint32_t 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.  See section 7.3.8 of the PN532 User Manual
      for more information on sending MIFARE and other commands.
  
      @param  uid           Pointer to a byte array containing the card UID
      @param  uidLen        The length (in bytes) of the card's UID (Should
                            be 4 for MIFARE Classic)
      @param  blockNumber   The block number to authenticate.  (0..63 for
                            1KB cards, and 0..255 for 4KB cards).
      @param  keyNumber     Which key type to use during authentication
                            (0 = MIFARE_CMD_AUTH_A, 1 = MIFARE_CMD_AUTH_B)
      @param  keyData       Pointer to a byte array containing the 6 bytes
                            key value
  
      @returns 1 if everything executed properly, 0 for an error
  */
  /**************************************************************************/
  uint8_t PN532::mifareclassic_AuthenticateBlock (uint8_t *uid, uint8_t uidLen, uint32_t blockNumber, uint8_t keyNumber, uint8_t *keyData)
  {
      uint8_t i;
  
      // Hang on to the key and uid data
      memcpy (_key, keyData, 6);
      memcpy (_uid, uid, uidLen);
      _uidLen = uidLen;
  
      // Prepare the authentication command //
      pn532_packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;   /* Data Exchange Header */
      pn532_packetbuffer[1] = 1;                              /* Max card numbers */
      pn532_packetbuffer[2] = (keyNumber) ? MIFARE_CMD_AUTH_B : MIFARE_CMD_AUTH_A;
      pn532_packetbuffer[3] = blockNumber;                    /* Block Number (1K = 0..63, 4K = 0..255 */
      memcpy (pn532_packetbuffer + 4, _key, 6);
      for (i = 0; i < _uidLen; i++) {
          pn532_packetbuffer[10 + i] = _uid[i];              /* 4 bytes card ID */
      }
  
      if (HAL(writeCommand)(pn532_packetbuffer, 10 + _uidLen))
          return 0;
  
      // Read the response packet
      HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer));
  
      // Check if the response is valid and we are authenticated???
      // for an auth success it should be bytes 5-7: 0xD5 0x41 0x00
      // Mifare auth error is technically byte 7: 0x14 but anything other and 0x00 is not good
      if (pn532_packetbuffer[0] != 0x00) {
          DMSG("Authentification failed\n");
          return 0;
      }
  
      return 1;
  }
  
  /**************************************************************************/
  /*!
      Tries to read an entire 16-bytes data block at the specified block
      address.
  
      @param  blockNumber   The block number to authenticate.  (0..63 for
                            1KB cards, and 0..255 for 4KB cards).
      @param  data          Pointer to the byte array that will hold the
                            retrieved data (if any)
  
      @returns 1 if everything executed properly, 0 for an error
  */
  /**************************************************************************/
  uint8_t PN532::mifareclassic_ReadDataBlock (uint8_t blockNumber, uint8_t *data)
  {
      DMSG("Trying to read 16 bytes from block ");
      DMSG_INT(blockNumber);
  
      /* Prepare the command */
      pn532_packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;
      pn532_packetbuffer[1] = 1;                      /* Card number */
      pn532_packetbuffer[2] = MIFARE_CMD_READ;        /* Mifare Read command = 0x30 */
      pn532_packetbuffer[3] = blockNumber;            /* Block Number (0..63 for 1K, 0..255 for 4K) */
  
      /* Send the command */
      if (HAL(writeCommand)(pn532_packetbuffer, 4)) {
          return 0;
      }
  
      /* Read the response packet */
      HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer));
  
      /* If byte 8 isn't 0x00 we probably have an error */
      if (pn532_packetbuffer[0] != 0x00) {
          return 0;
      }
  
      /* Copy the 16 data bytes to the output buffer        */
      /* Block content starts at byte 9 of a valid response */
      memcpy (data, pn532_packetbuffer + 1, 16);
  
      return 1;
  }
  
  /**************************************************************************/
  /*!
      Tries to write an entire 16-bytes data block at the specified block
      address.
  
      @param  blockNumber   The block number to authenticate.  (0..63 for
                            1KB cards, and 0..255 for 4KB cards).
      @param  data          The byte array that contains the data to write.
  
      @returns 1 if everything executed properly, 0 for an error
  */
  /**************************************************************************/
  uint8_t PN532::mifareclassic_WriteDataBlock (uint8_t blockNumber, uint8_t *data)
  {
      /* Prepare the first command */
      pn532_packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;
      pn532_packetbuffer[1] = 1;                      /* Card number */
      pn532_packetbuffer[2] = MIFARE_CMD_WRITE;       /* Mifare Write command = 0xA0 */
      pn532_packetbuffer[3] = blockNumber;            /* Block Number (0..63 for 1K, 0..255 for 4K) */
      memcpy (pn532_packetbuffer + 4, data, 16);        /* Data Payload */
  
      /* Send the command */
      if (HAL(writeCommand)(pn532_packetbuffer, 20)) {
          return 0;
      }
  
      /* Read the response packet */
      return (0 < HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer)));
  }
  
  /**************************************************************************/
  /*!
      Formats a Mifare Classic card to store NDEF Records
  
      @returns 1 if everything executed properly, 0 for an error
  */
  /**************************************************************************/
  uint8_t PN532::mifareclassic_FormatNDEF (void)
  {
      uint8_t sectorbuffer1[16] = {0x14, 0x01, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1};
      uint8_t sectorbuffer2[16] = {0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1, 0x03, 0xE1};
      uint8_t sectorbuffer3[16] = {0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0x78, 0x77, 0x88, 0xC1, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
  
      // Note 0xA0 0xA1 0xA2 0xA3 0xA4 0xA5 must be used for key A
      // for the MAD sector in NDEF records (sector 0)
  
      // Write block 1 and 2 to the card
      if (!(mifareclassic_WriteDataBlock (1, sectorbuffer1)))
          return 0;
      if (!(mifareclassic_WriteDataBlock (2, sectorbuffer2)))
          return 0;
      // Write key A and access rights card
      if (!(mifareclassic_WriteDataBlock (3, sectorbuffer3)))
          return 0;
  
      // Seems that everything was OK (?!)
      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.
  
      @param  sectorNumber  The sector that the URI record should be written
                            to (can be 1..15 for a 1K card)
      @param  uriIdentifier The uri identifier code (0 = none, 0x01 =
                            "http://www.", etc.)
      @param  url           The uri text to write (max 38 characters).
  
      @returns 1 if everything executed properly, 0 for an error
  */
  /**************************************************************************/
  uint8_t PN532::mifareclassic_WriteNDEFURI (uint8_t sectorNumber, uint8_t uriIdentifier, const char *url)
  {
      // Figure out how long the string is
      uint8_t len = strlen(url);
  
      // 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;
  
      // Note 0xD3 0xF7 0xD3 0xF7 0xD3 0xF7 must be used for key A
      // in NDEF records
  
      // Setup the sector buffer (w/pre-formatted TLV wrapper and NDEF message)
      uint8_t sectorbuffer1[16] = {0x00, 0x00, 0x03, len + 5, 0xD1, 0x01, len + 1, 0x55, uriIdentifier, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
      uint8_t sectorbuffer2[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
      uint8_t sectorbuffer3[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
      uint8_t sectorbuffer4[16] = {0xD3, 0xF7, 0xD3, 0xF7, 0xD3, 0xF7, 0x7F, 0x07, 0x88, 0x40, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
      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 (!(mifareclassic_WriteDataBlock (sectorNumber * 4, sectorbuffer1)))
          return 0;
      if (!(mifareclassic_WriteDataBlock ((sectorNumber * 4) + 1, sectorbuffer2)))
          return 0;
      if (!(mifareclassic_WriteDataBlock ((sectorNumber * 4) + 2, sectorbuffer3)))
          return 0;
      if (!(mifareclassic_WriteDataBlock ((sectorNumber * 4) + 3, sectorbuffer4)))
          return 0;
  
      // Seems that everything was OK (?!)
      return 1;
  }
  
  /***** Mifare Ultralight Functions ******/
  
  /**************************************************************************/
  /*!
      Tries to read an entire 4-bytes page at the specified address.
  
      @param  page        The page number (0..63 in most cases)
      @param  buffer      Pointer to the byte array that will hold the
                          retrieved data (if any)
  */
  /**************************************************************************/
  uint8_t PN532::mifareultralight_ReadPage (uint8_t page, uint8_t *buffer)
  {
      if (page >= 64) {
          DMSG("Page value out of range\n");
          return 0;
      }
  
      /* Prepare the command */
      pn532_packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;
      pn532_packetbuffer[1] = 1;                   /* Card number */
      pn532_packetbuffer[2] = MIFARE_CMD_READ;     /* Mifare Read command = 0x30 */
      pn532_packetbuffer[3] = page;                /* Page Number (0..63 in most cases) */
  
      /* Send the command */
      if (HAL(writeCommand)(pn532_packetbuffer, 4)) {
          return 0;
      }
  
      /* Read the response packet */
      HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer));
  
      /* If byte 8 isn't 0x00 we probably have an error */
      if (pn532_packetbuffer[0] == 0x00) {
          /* Copy the 4 data bytes to the output buffer         */
          /* Block content starts at byte 9 of a valid response */
          /* Note that the command actually reads 16 bytes or 4  */
          /* pages at a time ... we simply discard the last 12  */
          /* bytes                                              */
          memcpy (buffer, pn532_packetbuffer + 1, 4);
      } else {
          return 0;
      }
  
      // Return OK signal
      return 1;
  }
  
  /**************************************************************************/
  /*!
      Tries to write an entire 4-bytes data buffer at the specified page
      address.
  
      @param  page     The page number to write into.  (0..63).
      @param  buffer   The byte array that contains the data to write.
  
      @returns 1 if everything executed properly, 0 for an error
  */
  /**************************************************************************/
  uint8_t PN532::mifareultralight_WritePage (uint8_t page, uint8_t *buffer)
  {
      /* Prepare the first command */
      pn532_packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;
      pn532_packetbuffer[1] = 1;                           /* Card number */
      pn532_packetbuffer[2] = MIFARE_CMD_WRITE_ULTRALIGHT; /* Mifare UL Write cmd = 0xA2 */
      pn532_packetbuffer[3] = page;                        /* page Number (0..63) */
      memcpy (pn532_packetbuffer + 4, buffer, 4);          /* Data Payload */
  
      /* Send the command */
      if (HAL(writeCommand)(pn532_packetbuffer, 8)) {
          return 0;
      }
  
      /* Read the response packet */
      return (0 < HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer)));
  }
  
  /**************************************************************************/
  /*!
      @brief  Exchanges an APDU with the currently inlisted peer
  
      @param  send            Pointer to data to send
      @param  sendLength      Length of the data to send
      @param  response        Pointer to response data
      @param  responseLength  Pointer to the response data length
  */
  /**************************************************************************/
  bool PN532::inDataExchange(uint8_t *send, uint8_t sendLength, uint8_t *response, uint8_t *responseLength)
  {
      uint8_t i;
  
      pn532_packetbuffer[0] = 0x40; // PN532_COMMAND_INDATAEXCHANGE;
      pn532_packetbuffer[1] = inListedTag;
  
      if (HAL(writeCommand)(pn532_packetbuffer, 2, send, sendLength)) {
          return false;
      }
  
      int16_t status = HAL(readResponse)(response, *responseLength, 1000);
      if (status < 0) {
          return false;
      }
  
      if ((response[0] & 0x3f) != 0) {
          DMSG("Status code indicates an error\n");
          return false;
      }
  
      uint8_t length = status;
      length -= 1;
  
      if (length > *responseLength) {
          length = *responseLength; // silent truncation...
      }
  
      for (uint8_t i = 0; i < length; i++) {
          response[i] = response[i + 1];
      }
      *responseLength = length;
  
      return true;
  }
  
  /**************************************************************************/
  /*!
      @brief  'InLists' a passive target. PN532 acting as reader/initiator,
              peer acting as card/responder.
  */
  /**************************************************************************/
  bool PN532::inListPassiveTarget()
  {
      pn532_packetbuffer[0] = PN532_COMMAND_INLISTPASSIVETARGET;
      pn532_packetbuffer[1] = 1;
      pn532_packetbuffer[2] = 0;
  
      DMSG("inList passive target\n");
  
      if (HAL(writeCommand)(pn532_packetbuffer, 3)) {
          return false;
      }
  
      int16_t status = HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer), 30000);
      if (status < 0) {
          return false;
      }
  
      if (pn532_packetbuffer[0] != 1) {
          return false;
      }
  
      inListedTag = pn532_packetbuffer[1];
  
      return true;
  }
  
  int8_t PN532::tgInitAsTarget(const uint8_t* command, const uint8_t len, const uint16_t timeout){
    
    int8_t status = HAL(writeCommand)(command, len);
      if (status < 0) {
          return -1;
      }
  
      status = HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer), timeout);
      if (status > 0) {
          return 1;
      } else if (PN532_TIMEOUT == status) {
          return 0;
      } else {
          return -2;
      }
  }
  
  /**
   * Peer to Peer
   */
  int8_t PN532::tgInitAsTarget(uint16_t timeout)
  {
      const uint8_t command[] = {
          PN532_COMMAND_TGINITASTARGET,
          0,
          0x00, 0x00,         //SENS_RES
          0x00, 0x00, 0x00,   //NFCID1
          0x40,               //SEL_RES
  
          0x01, 0xFE, 0x0F, 0xBB, 0xBA, 0xA6, 0xC9, 0x89, // POL_RES
          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
          0xFF, 0xFF,
  
          0x01, 0xFE, 0x0F, 0xBB, 0xBA, 0xA6, 0xC9, 0x89, 0x00, 0x00, //NFCID3t: Change this to desired value
  
          0x06, 0x46,  0x66, 0x6D, 0x01, 0x01, 0x10, 0x00// LLCP magic number and version parameter
      };
      return tgInitAsTarget(command, sizeof(command), timeout);
  }
  
  int16_t PN532::tgGetData(uint8_t *buf, uint8_t len)
  {
      buf[0] = PN532_COMMAND_TGGETDATA;
  
      if (HAL(writeCommand)(buf, 1)) {
          return -1;
      }
  
      int16_t status = HAL(readResponse)(buf, len, 3000);
      if (0 >= status) {
          return status;
      }
  
      uint16_t length = status - 1;
  
  
      if (buf[0] != 0) {
          DMSG("status is not ok\n");
          return -5;
      }
  
      for (uint8_t i = 0; i < length; i++) {
          buf[i] = buf[i + 1];
      }
  
      return length;
  }
  
  bool PN532::tgSetData(const uint8_t *header, uint8_t hlen, const uint8_t *body, uint8_t blen)
  {
      if (hlen > (sizeof(pn532_packetbuffer) - 1)) {
          if ((body != 0) || (header == pn532_packetbuffer)) {
              DMSG("tgSetData:buffer too small\n");
              return false;
          }
  
          pn532_packetbuffer[0] = PN532_COMMAND_TGSETDATA;
          if (HAL(writeCommand)(pn532_packetbuffer, 1, header, hlen)) {
              return false;
          }
      } else {
          for (int8_t i = hlen - 1; i >= 0; i--){
              pn532_packetbuffer[i + 1] = header[i];
          }
          pn532_packetbuffer[0] = PN532_COMMAND_TGSETDATA;
  
          if (HAL(writeCommand)(pn532_packetbuffer, hlen + 1, body, blen)) {
              return false;
          }
      }
  
      if (0 > HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer), 3000)) {
          return false;
      }
  
      if (0 != pn532_packetbuffer[0]) {
          return false;
      }
  
      return true;
  }
  
  int16_t PN532::inRelease(const uint8_t relevantTarget){
  
      pn532_packetbuffer[0] = PN532_COMMAND_INRELEASE;
      pn532_packetbuffer[1] = relevantTarget;
  
      if (HAL(writeCommand)(pn532_packetbuffer, 2)) {
          return 0;
      }
  
      // read data packet
      return HAL(readResponse)(pn532_packetbuffer, sizeof(pn532_packetbuffer));
  }