Natural Resources, School of


Date of this Version



United States Patent Fletcher et al. 3,729, 129


A computer peripheral device is disclosed which in cludes a joystick whose displacement from a center position along two axes X and Y in either a plus (+) or a minus (-) direction is sensed. The displacement magnitude in either direction controls the rate of clock pulses provided by a variable frequency clock. The clock pulses from the two clocks are accumulated in two separate counters, whose contents are dis played. The contents of the counters are suppliable to a computer to update the contents of specific cells which define the position of a cursor on a display which is under computer control.