title: Using a non-5v analogReference voltage in the ADK2012
body: <p>I have a the ADK2012 arduino due-like device. I am using google's copy of the arduino software, and I can compile and run various sketches without trouble.</p>
  
  <p>I've got an LM35 that I've hooked up to an analog input. By default, the reference voltage is 5 volts. This seems to work fine, but I would like to use a different analogReference value, as documented here:</p>
  
  <p><a href="http://arduino.cc/en/Reference/AnalogReference" rel="nofollow">http://arduino.cc/en/Reference/AnalogReference</a></p>
  
  <p>Unfortunately, I'm having some trouble. When I use <code>DEFAULT</code> or <code>EXTERNAL</code> like this:</p>
  
  <pre><code>analogReference(DEFAULT);
  </code></pre>
  
  <p>I get this when I compile:</p>
  
  <pre><code>AnalogReadSerial.cpp: In function 'void setup()':
  AnalogReadSerial:12: error: invalid conversion from 'int' to 'eAnalogReference'
  AnalogReadSerial:12: error: initializing argument 1 of 'void analogReference(eAnalogReference)'
  </code></pre>
  
  <p>If I try to set it to <code>INTERNAL</code>, <code>INTERNAL1V1</code>, or <code>INTERNAL2V56</code>, I get errors like:</p>
  
  <pre><code>AnalogReadSerial.cpp: In function 'void setup()':
  AnalogReadSerial:12: error: 'INTERNAL' was not declared in this scope
  </code></pre>
  
  <p>I'm at a bit of a dead end here. I'm not familiar enough with Arduino or Wiring to know if this is a problem with the supplied device configuration, or an actual limitation of the physical hardware, or a bug or incompatibility internally.</p>
  
  <p>It's unfortunate that the hardware I'm using is relatively rare, and doesn't seem to have much documentation. I'd appreciate suggestions on where to start looking to fix this issue.</p>