USB Development kit Digispark Attiny85

One of the smallest Atmel processors, specifically Attiny85. It includes a USB connector and 6 I/O pins. Programming can be done through Arduino IDE 1.0 + (OSX / Windows / Linux)

Optional power supply via USB 5V or external 7-35V
500mA 5V controller on main board
Built-in USB
6 I/O pins (two for USB support)
8k Flash memory (after loading 6 bootloader)
I2C and SPI bus
PWM on 3 pins
ADC on 4 pins
LED for Power Indication and Test / Status (Pin0)