System is used for design, layout, and modification of large-scale-integrated (LSI) metal-oxide semiconductor (MOS) arrays. System is structured around small computer which provides real-time support for graphics storage display unit with keyboard, slave display unit, hard copy unit, and graphics tablet for designer/computer interface

Edge, T. M.

English

NASA Technical Reports Server

June 1975	 B75-10096 
NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Interactive Graphical Computer-Aided Design System 
.
An intractive graphical computer-aided design 
system has been developed including supporting 
software. The system is used for the design, layout, 
and modification of large-scale-integrated (LSI) 
theta]-oxide semiconductor (MOS) arrays. 
This interactive graphics system is structured 
around a small general-purpose computer and its 
supporting peripherals, dedicated to providing real-
time support for a graphics storage display unit with a 
keyboard, a slave display unit, a hard copy unit, and a 
graphics tablet for designer/computer interface. The 
designer sits at the graphics terminal using an 
inductive pen associated with the graphics tablet. A 
nonstoring cursor tracks the path of the pen about the 
tablet. The designer selects commands by applying 
pen pressure to designated areas of the tablet and
sends data to the computer by way of a data switch 
held in the other hand. The computer executes the 
commands given and reflects to the designer his 
graphical design needs. The designer can view 
portions of his work on the slave display unit while 
working with a different area on the master display. 
The designer also enters data through a keyboard and 
may obtain hard copies of the design. 
The software network and communication flow of 
this interactive graphics system is shown in the 
illustration. The basic functions of the software 
systems are: 
a. AIDS (artwork interactive design systems), 
b. PRF-AIDS (place route fold - artwork interactive 
design systems), 
.
Layout 
Data 
PRF-AIDS ) i-'( CPAT Library Update 
Data 
AIbS	 Full 
Data -CCTMN 
Base	 _i 
Tablet /
	
( AIDS-PRF ) L__._(	 MNTC 
•)•___( Full 
Artwork 
Data 
0- Denotes Software 
Layout ) 
Data	 , - Tape or Disk Storage
Interactive Graphics Software and Communication Flow
(continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	
will be free from privately owned rights. 
https://ntrs.nasa.gov/search.jsp?R=19750000096 2020-03-19T20:06:46+00:00Z
c. AIDS-PRF (artwork interactive design systems - 
place parts fold), 
d. CPAT (cell pattern generation), 
e. CTMN (cell to mask tape), and 
f. MNTC (mask tape to cell). 
AIDS is the center of the designer/computer 
software system. All actions at the tablet and terminal 
are focused through AIDS. When using AIDS, the 
designer steps through displays that allow the entering 
of data to establish design parameters prior to the 
design, such as component and line symbologies, the 
definitions of libraries and files, grid symbologies, 
and other commands for formatting. After these 
actions have been taken, the design field appears on 
the display, and the command menu attached to the 
tablet becomes active. Using the pen, commands are 
given to place, delete, name cells, add, copy, select 
levels, and scale, for the controlling of single items or 
groups of the design. 
PRF-AIDS is a software conversion program that is 
executed prior to the execution of AIDS. This 
program converts data generated by the automatic 
layout program. Automatic layout output consists of 
all cell placement data, shape set data, and line set 
data that constitute the total chip design. 
AIDS-PRF is a software program that is executed 
following AIDS. This program reads the AIDS data 
base and produces data in the format of the automatic 
layout data. It can be modified by the designer at the 
graphics terminal and recreated reflecting only the 
modifications performed. Thus the designer is given a 
chance to interrupt the normal flow of the custom LSI 
circuit design process and perform modifications that 
cannot be provided by automatic layout. 
CPAT is a software program that is executed 
following the execution of AIDS. In this mode, AIDS 
is used to perform cell design. The cell designer 
approaches the graphics terminal with a thought, a 
sketch, or an accurate layout of the artwork that will 
eventually become a standard cell of a binary library if 
desired. AIDS is used to digitize the information into 
blocks and shapes that make up the artwork of the 
cell. Upon completion of the cell design, the data is 
filed into the AIDS data base. Executing CPAT 
accesses the desired cell from the AIDS library and 
generates library update source data. This source is 
used as an input to generate a standard cell binary 
library.
The CTMN conversion program allows the user to 
output data from the AIDS library data base into a 
format accepted by the mask pattern generator. Mask 
pattern generator data is the block artwork exposure 
information that constitutes the mask levels of the 
circuit. This is the data that is processed into 
photographic plates for fabrication of the circuit 
design. Thus the user has the capability of directly 
defining masks from the graphics terminal. 
The MNTC conversion program provides the 
designer with a "last look" capability. The mask data 
tape is used as an input into the AIDS data base and 
is treated as a cell. AIDS can then be used to view the 
cell (total design), prior to the fabrication of the 
masks. AIDS is used to scan the masks in great detail 
at high gains for inspection and provides the designer 
with a matching group of hard copies to form a large 
mosaic of the total chip artwork. Acceptance of the 
chip design at this point releases the design to the 
mask facility. 
These software packages were written in 
FORTRAN. Although FORTRAN causes some 
real-time degradation with respect to high-density 
graphics, it provides a standard base for the 
distribution of the system software to industry. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Marshall Space Flight Center 
Code ATO1 
Marshall Space Flight Center, Alabama 35812 
Reference: B75-10096 
Patent status: 
Inquiries concerning rights for the commercial use 
of this invention should be addressed to: 
Patent Counsel 
Marshall Space Flight Center 
Code CCO1 
Marshall Space Flight Center, Alabama 35812 
Source: T. M. Edge
Marshall Space Flight Center 
(MFS-23157)
. 
Categories: 01 (Electronics - Components 
and Circuitry) 
02 (Electronics Systems) 
09 (Mathematics and Information 
Sciences)
[1 
B75-10096


Interactive graphical computer-aided design system

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