ublox6: Initial implementation

jrvandr: removed unnecessary mraa_init() and mraa_deinit()

The module implements support for the ublox-6 GPS sensor.  It was
tested on a Grove GPS device.

This module simply allows data to be retrieved from the device in the
form of NMEA sentences, and provides a method to write commands to the
device for configuration purposes.

It does not attempt to parse NMEA data -- that is a project in itself.
There are libraries available on the Internet, such as tinyGPS++ that
can handle that for you.

Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: Zion Orent <zorent@ics.com>
Signed-off-by: John Van Drasek <john.r.van.drasek@intel.com>

examples/javascript/ublox6.js

@@ -0,0 +1,99 @@
+/*jslint node:true, vars:true, bitwise:true, unparam:true */
+/*jshint unused:true */
+/*global */
+/*
+* Author: Zion Orent <zorent@ics.com>
+* Copyright (c) 2014 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.
+*/
+
+var GPSSensor = require('jsupm_ublox6');
+
+// Instantiate a Ublox6 GPS device on uart 0 (/dev/ttyS0).  This
+// works for the galileo G2.  
+
+// The Edison uses a different serial port, /dev/ttyMFD1, so if you
+// are using this example on an Edison board, specify the proper
+// port on the command line, eg: 'node ublox6.js /dev/ttyMFD1'
+// process.argv.length contains all command-line strings
+// argument 0 is "node"
+// argument 1 is "ublox6.js"
+// argument 2, if it exists, will be the override port,
+//    such as /dev/ttyMFD1 on Edison
+
+var defaultPort = "/dev/ttyS0";
+if (process.argv.length > 2)
+	defaultPort = process.argv[2];
+
+var myGPSSensor = new GPSSensor.Ublox6(0, defaultPort);
+
+if (!myGPSSensor.setupTty(GPSSensor.int_B9600))
+{
+	console.log("Failed to setup tty port parameters");
+	process.exit(0);
+}
+
+// Collect and output NMEA data.
+
+// This device also supports numerous configuration options, which
+// you can set with writeData().  Please refer to the Ublox-6 data
+// sheet for further information on the formats of the data sent and
+// received, and the various operating modes available.
+
+var bufferLength = 256;
+var nmeaBuffer  = new GPSSensor.charArray(bufferLength);
+
+function getGPSInfo()
+{
+	// we don't want the read to block in this example, so always
+	// check to see if data is available first.
+	if (myGPSSensor.dataAvailable())
+	{
+		var rv = myGPSSensor.readData(nmeaBuffer, bufferLength);
+
+		var GPSData, dataCharCode, isNewLine, lastNewLine;
+		var numlines= 0;
+		if (rv > 0)
+		{
+			GPSData = "";
+			// read only the number of characters
+			// specified by myGPSSensor.readData
+			for (var x = 0; x < rv; x++)
+				GPSData += nmeaBuffer.getitem(x);
+			process.stdout.write(GPSData)
+		}
+
+		if (rv < 0) // some sort of read error occured
+		{
+			console.log("Port read error.");
+			process.exit(0);
+		}
+	}
+}
+
+setInterval(getGPSInfo, 100);
+
+// Print message when exiting
+process.on('SIGINT', function()
+{
+	console.log("Exiting...");
+	process.exit(0);
+});