A hardware and software interface between a graphics terminal and the SCC 650 computer

This paper describes the design of a digital interface between a graphic terminal and the SCC-650 computer. The graphic terminal-computer combination can be used as a stand alone system for small applications or can be used as a satellite processor for a larger system such as the IBM System 360, The interface is designed utilizing DTL NAND type integrated circuits. Its primary functions may be divided into three main categories: (1) to give level conversion, (2) control, and (3) data manipulation. All requests for data transfers are initiated by the computer, the interface then assumes a control mode which handles the data transfer to or from the graphics terminal. Once the transfer is complete, the computer is notified that it may initiate another request. Data is converted from bit serial to parallel word form by the interface during the data transfer. A function keyboard has been implemented which may transfer any one of 2048 different command words to the computer. A software package was written in SCC-650 Assembler which will utilize the graphics terminal as an input/output processor for an electronic circuit design program such as ECAP or CIRCUS, This program will allow a user to draw the exact circuit to be analyzed on the graphics terminal and then ask for specific results to be displayed in either numerical or graphical form, The circuit may then be changed by adding or deleting elements and re-analyzed --Abstract, page ii