Touch screen displays are in the form of either large screen monitors, such as those used in PC systems, or small LCDs, used in microcontrollerbased systems. Although the principle of operation is the same in either case, in this article the small LCD type touch screen displays are considered. Such displays usually have resolutions of 128x64 pixels and are used in battery-operated intelligent devices. A touch screen LCD is basically a combination of a graphics LCD (GLCD) and a touch sensitive panel mounted on top of the GLCD. The two ...