Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Electrical Engineering

First Advisor

D.E. Sander


An interface between a 64X240 graphic liquid crystal display and an electronic voting system is developed. Interface hardware is based on the RCA 1802 eight-bit microprocessor. A method of utilizing a liquid crystal display with a limited viewing angle is presented. The display is positioned upside down, and characters are manipulated by the interface software to appear correct. Two-character fonts are available to the user. A 6X8 character font allows a maximum of pix lines with thirty characters per line to be displayed. Display size limits the 30X42 font to one line of seven characters. Run-length encoding is used to condense storage of the 30X42 font in the 4K X 8-bit PROM.A significant development presented in this thesis is a method for converting a bottom view display into a top view display. This conversion is accomplished in a two-step procedure. First, the bottom view display is positioned upside down so the window of maximum visibility is in the top view cone. Then, since the display is used in the graphic mode, characters are made to appear upside down on the display. Combining these two factors, positioning the display upside down and writing characters upside down, a bottom view display is transformed into a top view display. The method for writing characters upside down is addressed in Section V.

Library of Congress Subject Headings

Liquid crystal devices



Number of Pages



South Dakota State University


No Copyright - United State