Freaduino UNO is an Arduino compatible board. It is based on Arduino UNO Rev3 design. So you can use Freaduino as Arduino UNO Rev3 . All code shield and IDE for Arduino UNO Rev3 are also valid on Freaduino UNO. Some visible improvement on hardware make Freaduino UNO more flexible and easier to use. For example: 3.3v or 5v IO selectable allow you connect some 3.3v modules (such as XBee) to Freaduino directly. SPI COM and IIC bus breakout make bus connect easier. The Arduino Uno Rev3 is a microcontroller board based on the ATmega328 (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs) 6 analog inputs a 16 MHz crystal oscillator a USB connection a power jack an ICSP header and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. The Uno differs from all preceding boards in that it does not use the FTDI USB-to-serial driver chip. Instead it features the Atmega8U2 programmed as a USB-to-serial converter."UNO" means one in Italian and is named to mark the upcoming release of Arduino 1.0.