Develop the interface provided by the motherboard:
1. Can be powered by USB or 5v or 7-35v (automatic matching) extra power supply
2. There is a 500ma 5V regulator on the motherboard.
3.USB embedding (serial debugging)
4.6 I/O Pins (2 for USB support)
5.8k Flash Memory (about 6k after bootloader)
6. I2C and SPI (vis USI)
7. PWM on 3 pins (more possible with Software PWM)
8. ADC on 4 pins
9.Power LED indicator and Test/Status LED (in Pin0)