1. Support for the Arduino IDE 1.0 + (OSX/Windows/Linux).
2. Power via USB or External Source or 7-16 v to 5 v (automatic selection).
3. The On - board, 150 ma 5 v Regulator.
4. Built - in USB and serial was debugging).
5. 6 I/O Pins (2 are informs the for USB only if your program actively communicates over USB, otherwise you can use all 6 even if you are programming via USB).
6. 8 k Flash Memory (about 6 k after bootloader).
7. The I2C and SPI (vis USI).
8. PWM on 3 pins (more possible with Software PWM).
9. The ADC on 4 pins.
10. The Power LED and the Test/Status leds.