Design And Development Of A Computer Graphics System Based On The upd7220A Graphics Display Controller

Abstract

An interactive microcomputer graphics system is presented. The system overcomes the drawing speed, memory size and resolution limitations of typical 8-bit microprocessor systems by incorporating the )JPD7220A Graphics Display Controller (GDC). The GDC is positioned between the microprocessor bus and the video display memory with an RGB colour monitor acting as the display medium. The various interfaces between these main system components are discussed. The video display memory is organized in three planes of 256 x 4 kbits each. The resulting display has a resolution of 480 x 540 pixels (interlaced) in eight colours with four image areas accessible within the display memory. Commands are issued by the host BBC microcomputer in micro-coded form,and are decoded by the GDC's internal logic to perform .the required operations.

A simulation of the Auger process has been attempted and displayed in graphics form on the RGB monitor to validate the system.