Confused......! we are not charging any functionality here. Just the ATMEGA328 is replaced with ATMEGA8. In terms of program memory it differse from Arduino UNO. The freeduino with ATMEGA8 does all functionality of Arduino UNO. Freeduino also comes with USB port for the programming through PC using Arduino programming tool. As you plug the USB cable(A-B) with Freeduino to PC, a driver software is necessary to install. Silicon lab CP212X USB to UART driven can be downloaded from the download tab of this product page. Rest of the features are similer to Arduino.Still this freeduino is powerfull in interfacing with GSM Modem,GPS, Bluetooth,Wifi, touch screen, TFT Modules and Motor Divers for your robotics very easily. Programming is verry simple in Arduino.