vdiv: Added vdiv C source.

Multiple changes related to building the vdiv c source w/c example.

    * Renamed GroveVdiv to vdiv (all cases) throughout source, examples,
    directory names, and documentation.

    * Added C source.

    * Tested C sensor code on edison

    * Updated CMakeLists.txt for examples-c to build from
    <sensorname>-c.  This was a small change to get c examples to build
    for sensors in which the C++ does NOT wrap the C.

    * Added C example for vdiv.

Signed-off-by: Noel Eck <noel.eck@intel.com>

examples/c++/vdiv.cxx

@@ -0,0 +1,67 @@
+/*
+ * Author: Jon Trulson <jtrulson@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.
+ */
+
+#include <unistd.h>
+#include <iostream>
+#include <signal.h>
+#include "vdiv.hpp"
+
+using namespace std;
+
+bool shouldRun = true;
+
+void sig_handler(int signo)
+{
+  if (signo == SIGINT)
+    shouldRun = false;
+}
+
+
+int main ()
+{
+  signal(SIGINT, sig_handler);
+
+//! [Interesting]
+  // Instantiate a Grove Voltage Divider sensor on analog pin A0
+  upm::VDiv* vDiv = new upm::VDiv(0);
+
+  // collect data and output measured voltage according to the setting
+  // of the scaling switch (3 or 10)
+  while (shouldRun)
+    {
+      unsigned int val = vDiv->value(100);
+      float gain3val = vDiv->computedValue(3, val);
+      float gain10val = vDiv->computedValue(10, val);
+      cout << "ADC value: " << val << " Gain 3: " << gain3val 
+           << "v Gain 10: " << gain10val << "v" << endl;
+
+      sleep(1);
+    }
+//! [Interesting]
+
+  cout << "Exiting..." << endl;
+
+  delete vDiv;
+  return 0;
+}