Document Type


Date of Award


Degree Name

Master of Science in Electrical Engineering - (M.S.)


Electrical Engineering

First Advisor

Anthony D. Robbi

Second Advisor

Chung H. Lu

Third Advisor

John D. Carpinelli


A seven-by-forty-eight tricolor LED display panel is designed and built around the 68HC11 MCU.

Four bilateral switching transistors (4066) are used in a Wien bridge configuration to drive each tri-color LED. With this circuitry one is able to drive the tricolor LED symmetrically. An alternative design that uses only two switching transistors is also offered.

A software program was developed to output on the display scrolling and fixed messages. Each message could be displayed in a different color (Red, Green and Yellow) and at a different speed (Slow, Fast, and Medium). The program also includes an editor with insertion and deletion capabilities.

The CPU idle time (compared to the system's over all execution time per display function) is used as a measure of the system performance. The results showed that more than 95% of the MCU cycles are available for other functions. Fixed message display functions use far fewer cycles than the scrolling messages.



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