text: /*jslint node:true, vars:true, bitwise:true, unparam:true */
  /*jshint unused:true */
  
  /*
  * Author: Jon Trulson <jtrulson@ics.com>
  * Copyright (c) 2015 Intel Corporation.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, sublicense, and/or sell copies of the Software, and to
  * permit persons to whom the Software is furnished to do so, subject to
  * the following conditions:
  *
  * The above copyright notice and this permission notice shall be
  * included in all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
  
  // Load PN532 module
  var pn532 = require('jsupm_pn532');
  
  // Instantiate an PN532 on I2C bus 0 (default) using gpio 3 for the
  // IRQ, and gpio 2 for the reset pin.
  var myNFCObj = new pn532.PN532(3, 2);
  
  function writeUrl()
  {
      if (uidSize.getitem(0) != 7)
      {
          console.log("This example will only write an NDEF URI to preformatted");
          console.log("Mifare Ultralight or NTAG2XX tags");
          exit();
      }
  
      // 48 bytes is maximum data area on ultralight cards, so we use that
      // as the maximum datasize here.  Obviously if you have a bigger
      // card, you can write more data.
      if (!myNFCObj.ntag2xx_WriteNDEFURI(pn532.PN532.NDEF_URIPREFIX_HTTP, 
                                         url, 48))
      {
          // failure
          console.log("Failed to write NDEF record tag.");
          exit(1);
      }
  
      console.log("Success, URL record written to tag.");
  }
  
  function toHex(d, pad)
  {
      // pad should be between 1 and 8
      return  ("00000000"+(Number(d).toString(16))).slice(-pad)
  }
  
  function exit()
  {
  	clearInterval(myInterval);
  	myNFCObj = null;
  	pn532.cleanUp();
  	pn532 = null;
  	console.log("Exiting");
  	process.exit(0);
  }
  
  // When exiting: clear interval, and print message
  process.on('SIGINT', function()
  {
  	exit();
  });
  
  // "main"
  if (!myNFCObj.init())
  	console.log("init() failed");
  
  var vers = myNFCObj.getFirmwareVersion();
  
  if (vers)
  	console.log("Got firmware version: " + toHex(vers, 8));
  else
  {
  	console.log("Could not identify PN532");
  	exit();
  }
  
  // Now scan and identify any cards that come in range (1 for now)
  
  // Retry forever
  myNFCObj.setPassiveActivationRetries(0xff);
  
  myNFCObj.SAMConfig();
  
  var uidSize = new pn532.uint8Array(0);
  var uid = new pn532.uint8Array(7);
  
  // the URL we want to add as an NDEF record
  // NOTE: this cannot exceed 34 characters.
  url = "iotdk.intel.com";
  
  var myInterval = setInterval(function()
  {
  	for (var x = 0; x < 7; x++)
  		uid.setitem(x, 0);
  	if (myNFCObj.readPassiveTargetID(pn532.PN532.BAUD_MIFARE_ISO14443A,
  		                         uid, uidSize, 2000))
  	{
  		// found a card
  		console.log("Found a card: UID len " + uidSize.getitem(0));
  		process.stdout.write("UID: ");
  		for (var i = 0; i < uidSize.getitem(0); i++)
                  {
                          var byteVal = uid.getitem(i);
  			process.stdout.write(toHex(byteVal, 2) + " ");
                  }
  		process.stdout.write("\n");
  		console.log("SAK: " + toHex(myNFCObj.getSAK(), 2));
  		console.log("ATQA: " + toHex(myNFCObj.getATQA(), 4));
  		console.log(" ");
  
                  // write the URL
                  writeUrl();
              	clearInterval(myInterval);
                  return;
  	}
  	else
  		console.log("Waiting for a card...");
  }, 1000);
  
  