Speedometer display of simulated analog needle and odometer on electroluminescent panel

摘要

An electroluminescent panel is provided for displaying a simulation of a speedometer for a vehicle. The simulation includes a rotating needle for indicating the speed of the vehicle and a drum type odometer for keeping track of the total mileage of travel of the vehicle. The electroluminescent panel has a microcomputer and a video ram associated therewith. On successive (Direct Memory Access) DMA periods of a millisecond operating cycle, the microcomputer is programmed to read columns of data out of the video ram to be displayed as corresponding columns of pixels on the electroluminescent panel. Between the successive Direct Memory Access periods of the millisecond operating cycle, the microcomputer is programmed to execute needle control and odometer control routines to update the data in the video ram in response to an input fed to the microcomputer indicative of the speed of the vehicle upon which the electroluminescent panel is mounted.