CIRCUIT FOR INTERFACING MOUSE INPUT DEVICE TO COMPUTER SYSTEM

摘要

A computer system mouse-type input device. Movements of a track-ball motion sensor are converted to quadrature signals and are accumulated in a counting circuit. The contents of the counter are pulse-position modulated with waveforms characteristic of a resistive-capacitive charging circuit and are read periodically by a computer input channel normally used for input of potentiometer-generated commands. The pulse-position modulated signals are converted to digital values used by the computer to position the cursor on a display screen.