NAVIGATION INPUT FOR A HANDHELD ELECTRONIC DEVICE

摘要

A handheld electronic device that includes a display screen located above a trackball-based user input device is disclosed. At least one sensor is operatively associated with the trackball and configured to sense motion induced in the trackball when the trackball is rotated by substantially circular motion applied about an exposed portion of the trackball. The sensor is further configured to output electronic data representative of the sensed induced trackball motion. A microprocessor receives the output electronic data from the at least one sensor as input data and processes the input data into cursor guidance instructions. These cursor guidance instructions are outputted to the display screen and affect one-dimensional, substantially continuous cursor movement on the display screen in correspondence with the sensed trackball motion.