/******************************************************************************
* TI INA219 hi-side i2c current/power monitor Library for Arduino
*
* http://www.ti.com/product/ina219
*
* 6 May 2012 by John De Cristofaro
*
*
* Tested at standard i2c 100kbps signaling rate.
*
* This library does not handle triggered conversion modes. It uses the INA219
* in continuous conversion mode. All reads are from continous conversions.
*
* A note about the gain (PGA) setting:
*	The gain of the ADC pre-amplifier is programmable in the INA219, and can
*	be set between 1/8x (default) and unity. This allows a shunt voltage 
*	range of +/-320mV to +/-40mV respectively. Something to keep in mind,
*	however, is that this change in gain DOES NOT affect the resolution
*	of the ADC, which is fixed at 1uV. What it does do is increase noise
*	immunity by exploiting the integrative nature of the delta-sigma ADC.
*	For the best possible reading, you should set the gain to the range
*	of voltages that you expect to see in your particular circuit. See
*	page 15 in the datasheet for more info about the PGA.
*
* Known bugs:
*     * may return unreliable values if not connected to a bus or at
*	bus currents below 10uA.
*
* Arduino 1.0 compatible as of 6/6/2012
*
* Dependencies:
*    * Arduino Wire library
* 
* MIT license
******************************************************************************/