ABSTRACT Name : Fajri Study Program : Computer Science Title : USB Protocol in Implementation of "Touch Input" Keyboard Software Using AVR ATxmega 256A3BU This thesis discusses the keyboard software implementation by using AVR ATxmega 256 A3BU as its micrococontroller. Software keyboard was built using touch sensors as the input mechanism. To gain access to any USB port on the PC we need to know how the USB protocol system is. Therefore in this thesis will be explained how the USB protocol system that has been implemented in the program. The hardware of this keyboard has 32 channels where each channel consists of a touch sensor. The method used to build software based on this 32 channel requirement is QMatrix Acquisition method in Atmel QTouch library. Key words: Keyboard, touch, USB protocol, AVR ATxmega256 A3BU