According to the documented pin limitations for the arduino Mega R3, you have available a total of 800mA to sink from all the VCC pins. The same for the GND pins. http://playground.arduino.cc/Main/ArduinoPinCurrentLimitations
Another source says that if you use Vin you are limited to 1A due to a diode in the arduino board.
1)My question is whether the 800mA available for the VCC pins comes from the Vin pin or another source.
2)Essentially, I am wondering if I can have the 800mA available for the VCC/GND pins AND an additional 1A from Vin, giving me a total of 1.8A available.
3)If this can be done then I take it I just have to upgrade my 1A arduino power supply to the 2A. Is this correct?
4) Lastly, if (2) is true, where would I sink the additional 1A of current coming from Vin if the sum of all the GND pins are still limited to 800mA?
Please number responses based on question numbering. Thanks!