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Support for the Arduino IDE 1.0+ (OSX / Win / Linux) Power via USB or External Source - 5V or 7 -35V (automatic selection) On-board 500ma 5V Regulator Built-in USB(and serial debugging) 6 I/O Pins (2 are used for USB only if your program actively communicates over USB otherwise you can use all 6 even if you are programming via USB)