The coordinate graphics unit

Abstract

The purpose of this coordinate graphics project is to test and evaluate an unconventional hardware design for plotting and displaying scientific and mathematical functions. This design project is interfaced with a 6502 microprocessor based micromputer under the commercial name of OSl The graphics is superimposed on alphanumeric characters of the OSI 440 alphanumeric board. It is a raster scan approach to graphics which uses one byte per bright dot and does not require memory for the dark undots on the video display. It has been designed to compete with the bit-per-point raster scan approach. The information for the dots is stored in RAMs as 2. variable line record of horizontal coordinates, separated by codes indicating the end of each line. Each horizontal record of coordinates corresponds to a single line. The horizontal coordinates are used to set corresponding bit pattern into a 256 x 1 fast bi.polar memory which controls the video signal for the single line. The fast memory is loaded again for each line scan.