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V L S
The VAX Layout System
for Board Design
EXECUTIVE SUMMARY
CAD Systems Engineering
CADCAM Technology Center
Chelmsford, Massachusetts
For Internal Use Only
VLS - the VAX Layout System - is a computer-aided
design (CAD) system for the physical layout of
Digital's printed-wiring boards. Its purpose is
to support Digital's layout needs for both current
and advanced technologies. Because VLS is used only
for Digital designs, it has several advantages over
commercial CAD systems:
o VLS has an open architecture that allows it to be
adapted to the needs of its users.
o VLS is partnered with Digital's advanced technology
programs to keep our products competitive.
o VLS source code can be provided to sites that want
to adapt applications to their unique needs.
o VLS is already a standard within Digital - more and
more designers have VLS experience; more and more
sites can share design information.
o VLS is the only layout system that supports DEC
Standard 030.
VLS is continually upgraded to support leading-edge
board technology. Timely releases of new versions
and upgrades provide quick response to customer
requirements.
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VLS can run on virtually any VAX or MicroVAX. Its
graphics can be displayed on a number of graphic
devices, including:
VAXstation II/GPX
METHEUS 3610 and 530
LEXIDATA 3400 and LEX 90
DIGITAL VT240, 241, 330, and 340
DIGITAL VS3000
1 CAD Systems Engineering
VLS was developed and is upgraded and supported by the
CAD Systems Engineering (CADSE) group. CADSE is based
in Chelmsford, Massachusetts, at Digital's CAD/CAM
Technology Center.
CADSE provides software testing and site support.
Training is provided (by the Engineering Technical
Training group) for all VLS customers. As a VLS
customer, you receive software that has been
thoroughly tested from a user's point of view. For
each site, a site representative acts as liaison
between VLS users at the site and the VLS development
group. New users receive training in the basics of
VLS, and experienced users can choose from a variety
of advanced courses.
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2 Open Architecture
The open architecture of VLS gives it several major
advantages. One significant advantage is that CADSE
can provide the choice of three VLS kits, each serving
different customer needs:
1. The basic kit, for design sites
2. The development kit, for sites that also write
their own software
3. The read-only kit, for sites such as manufacturing
and field service that use VLS for informational
purposes rather than for creating designs
The open architecture also makes it possible for a
site, within its chosen kit, to use only those sets
of functions that meet the site's needs. As a further
advantage, the open architecture of VLS enables CADSE
or a site to add new functions.
3 System Overview
VLS combines both automatic and interactive features,
providing a wide range of capabilities across the
design process. VLS consists of two major parts:
1. The VLS environment - a set of system-wide features
such as graphics. The VLS environment is closely
integrated with the VMS operating system.
2. Applications - sets of functions for specific
design tasks. An application can be added or
removed as needed. Examples of design tasks
performed by VLS applications include: reading in a
design from a logic design system, automatically
adding components, manually adding and moving
components, automatically routing the board,
manually adding and moving lines of etch, and
performing engineering checks such as signal
integrity analysis and manufacturing rules
checking.
For Internal Use Only 3
Technologies Supported. VLS supports both current and
advanced printed-wiring board technologies, including:
o Design Technologies
Intrusive mount technology
Multilayer technology
Surface mount technology
Planar resistor technology
Tab technology
Thin-film technology
Thick-film hybrid technology
o Engineering Technologies
TTL
High-frequency ECL
CMOS
Analog/power supply
Design Size Capacities. Capacities such as board
dimensions, number of layers, and number of
connections are not necessarily limiting factors for
the VLS data structure. The data structure itself can
accommodate a wide range of design sizes. There are
some size limitations in VLS applications. However, if
any of these limitations restricts a design project,
the application can usually be modified as needed.
Present capacities are shown in Table 1.
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Table 1: VLS Capacities (Per Design)
_______________________________________________________
Parameter Software Capacity
_______________________________________________________
Board dimensions: 32 x 32 inches
Layers (total): 32
Signal layers: 16
Connections: 65,000
Networks: 5,000
Nodes per network: 5,000
Unique part 1,000
numbers:
Part instances: 2,000
Pins: 12,000
Pins per part: 2,000
Gates per part: 30
_______________________________________________________
Human Interface. Special features add to the usability
of VLS:
o VLS uses the numeric keypad found on all Digital
keyboards to speed input. The keypad keys are
used to enter commands to VLS, so that only one
keystroke is needed for most commands. Keys are
kept consistent from one application to another,
and a keypad diagram can be displayed at any time.
For Internal Use Only 5
o On-line help messages provide overviews of each
application as well as the information needed to
use each function key, command, and option.
o VLS provides reports on the results of design
operations. The reports can be in the form of text
files that you read during a VLS session and text
files that you read later or send to a printer.
o Pictorial highlighting lets you differentiate
selected items on the graphics screen by means
of colors and blinking.
o Error messages are displayed as they occur; you can
also send them to a file for later analysis.
o Controlled access lets you specify which users can
modify which types of data, in order to prevent
accidental deletion or other undesirable changes to
the design.
4 The Design Process
The VLS design process begins with input from the
schematic data system and ends with data files that
can be sent to manufacturing. This section highlights
the major areas of the design process.
1. Using Schematic Data
VLS can interface with all schematic tools used at
Digital, such as VALID, DAISY, and SILVAR LISCO. Once
the schematic information from one of these systems is
available in a form that can be read into VLS, you are
ready to lay out the board.
2. Designing a Board with VLS
At the beginning of the VLS process, the designer
builds a "cover" (named for the cover sheet that once
accompanied the paperwork for a design). The cover
consists of data that applies to the entire design,
6 For Internal Use Only
such as definition of holes, pads, and conductors;
board outline; routing, placement, and restricted
areas; and administrative information.
How VLS Handles Parts. VLS lets you add standard
Digital parts or create your own. Every component
used in a design has a part description that contains
electrical and physical data (as well as the Digital
part number). Each part description is contained in a
file, and these files are maintained in a library at
each design site.
In addition, VLS allows a designer or part librarian
to modify an existing part or create a completely new
one. These new and modified parts are often shared
between sites, thus saving design time.
Placing the Parts on the Design. VLS provides
automatic, interactive, and specialized placement
applications. These applications optimize component
placement and connection length. They let you
reposition components, change their mounting layers,
fix or unfix components, rotate a component or group
of components, and swap equivalent gates or pins of
identical components to minimize connection length.
Routing. One of the strongest features of VLS is the
way it routes designs. VLS provides both automatic and
interactive routers. For many designs, the automatic
router can provide 100% routability. Routing is
fast, and it can be done in batch mode to free the
designer's terminal and thus further speed the design
process. Interactive routing allows the designer to
incorporate engineering changes at any point in the
design process without completely rerouting the board.
The VLS routers provide ease of use and flexibility
in adding and modifying etch. The routers provide
via-minimization, line-spreading, multiple spacing
technologies, copper-sharing, and crosstalk analysis.
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VLS offers several routing alternatives, such as
diagonal, orthogonal, and reentrant routing.
Verifying the Data. VLS provides applications that
you can use to check for errors in the design. At
any point in the design process you can check the
integrity of your data. In addition, there are two
categories of checks: (1) applications used to verify
design data and manufacturability and (2) applications
used to verify engineering data.
Applications that verify design data and
manufacturability can check for information such as:
Hole, pad, and conductor definition
Component placement and orientation
Etch and via placement
Electrical continuity and spacing
Other VLS applications perform engineering checks such
as:
Crosstalk analysis
Thermal reliability analysis
Reflection analysis
3. Interface to Manufacturing
Before a design goes to manufacturing, certain types
of data are added so that the board can actually
be built and tested. VLS provides applications that
add such data as thieving pads, soldermask, and test
points.
Finally, VLS generates the files that are sent to
manufacturing. These files include:
The data files that contain all the design data
Files of documentation drawings that can be sent to
a plotter
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The parts list, which contains reports listing all
parts on the design
5 Enhancements and New Releases of Software
The CADSE developers use their software expertise
and knowlege of state-of-the-art board design
to continually improve and enhance VLS. These
improvements appear in three types of software
releases:
o New versions of VLS, which incorporate major new
functions
o Upgrades of the present version, including
additional functions as well as solutions to
problems found in the original release
o Informal releases of individual applications,
usually in response to problems found by a site
All sites are notified of each type of release.
Enhancements result from the requirements of
new technologies, process improvements, and the
suggestions of our customers. VLS customers also file
software problem reports (SPRs) to detail any problems
with the way VLS software runs. The CADSE developers
respond to high-priority SPRs in a timely manner, in
order to prevent loss of the designers' time.
Some enhancements are made by our customers. VLS
users can design their own applications and can make
them available to other users through a VAXnotes
conference called the VLS Toolshed. If a user-designed
application is of general interest and meets CADSE
programming standards, it can be incorporated into the
CADSE-supported kit, so that it is available to all
VLS users.
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6 Customer Support
The support arm of CADSE is called CADSTAR, for CAD
Support, Test and Release. CADSTAR's Test and Release
group works to schedule the release of enhancements,
respond to SPRs, and ensure that the software has been
adequately tested before it is released.
The CADSTAR support group provides a variety of
services. The most important is the personalized
support provided to each site by its CADSTAR
representative. The CADSTAR representative is the
liaison between CADSE and the local site support
person, who is the focal point for all VLS users at
the site.
The CADSTAR representative's role includes the
following duties:
o Conveying to the CADSE developers the site's
issues, concerns, accomplishments, and upcoming
projects
o Representing the site's concerns when enhancements
are being scheduled
o Assisting the local site support representative in
- Determining present and future needs
- Evaluating and solving VLS software problems
- Evaluating and solving system problems
In addition, each new site is supported initially by a
CADSTAR representative who is knowledgeable about what
is needed to get VLS up and running and who can help
with the initial issues of system configuration and
training.
CADSTAR provides many other forms of support to the
sites using VLS:
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o Every month, CADSE sponsors the VLS User Forum,
which brings together members of the VLS community
to discuss topics of interest. Typical Forum topics
include new tools, desired enhancements, and ways
of using VLS to perform design tasks.
Those attending a User Forum may include VLS
users, local site support people, CADSTAR site
representatives, CADSE developers, and managers
from both sites and CADSE.
o The CADSE System Manager is available as a
consultant to the sites' system managers and local
site support people.
o Each new version, update version, and informal
application release is thoroughly tested before
it is released to the sites. All sites are given
timely notification of each release.
VAXnotes Conferences for VLS Users
There are two VAXnotes conferences devoted to VLS;
they are regularly monitored by CADSE developers and
CADSTAR representatives:
1. The VLS conference provides a means for VLS
users to communicate with each other and with the
CADSE developers to present their suggestions and
concerns.
2. The VLS Toolshed conference provides information
about applications and command files that are
not yet supported by CADSE but that are useful to
designers. Most of these tools are developed by VLS
users, who graciously make them available to other
sites.
In addition, there are two related conferences:
DataLink Notes and Parts_Libraries Notes.
VLS Documentation
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CADSTAR makes sure there is documentation for VLS
applications, and that new features are documented.
All VLS documentation is available on line as well
as in printed form. There are several types of VLS
documents:
o Applications are self-documenting through help
screens for quick reference. (Help files can be
printed out for detailed study.)
o The manual Using VLS to Design Printed-Wiring
Boards introduces the new user to VLS.
o User Guides give details of how to use individual
VLS applications.
o Task Guides explain how to use VLS to perform
specific design tasks, such as producing
documentation drawings.
o The VLS Glossary defines VLS terminology.
o Comprehensive, user-oriented release notes describe
changes to each new version of VLS.
Installation
CADSTAR maintains three important automatic software
tools that save time for the system manager at a VLS
site:
1. The VLS Installation Process automates the
installation of the VLS kit, either for the
first time or for a new version. The Installation
Process includes prompts, help messages, and
recommendations, as well as the Installation Guide.
2. The Site Update procedure automates the
installation of individual applications as they
are released.
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3. The Version Checker compares a site's applications
with those released by CADSE to ensure that
the site's applications are up to date. Since
individual applications may be released as soon
as they are upgraded, running the Version Checker
saves valuable time.
7 On-Site Customer Resources
Each VLS site is expected to provide certain
resources. The CADSTAR representatives work with the
site to put these resources in place. The following
resources are the minimum that a site needs to have
available in order to use VLS:
o Local site support person - the focal point
for users at the site and for the CADSTAR site
representative
o Local system management expertise
o Experienced or adequately trained printed-wiring
board designers
o Cover library - a set of files of cover data that
are appropriate for the site's needs
o Part library - a set of files of part descriptions
that conform to Digital standards and that are
appropriate for the site's needs
The local site support person serves as the primary
point of contact between the site and CADSE.
This person is the site's first resource for
troubleshooting VLS problems, submitting and tracking
enhancement requests, disseminating information that
is forwarded by the CADSTAR site representative,
ensuring that the VLS software is up to date, and
working with the local system manager to properly
install and tune VAX hardware and software.
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The local site support person and the site's CADSTAR
representative provide two-way communication between
the site and CADSE at all times.
Since the process of identifying and acquiring all
the necessary resources may be time-consuming,
it is usually a good idea to begin the process as
soon as you have decided to purchase VLS. A CADSTAR
representative can help you begin the process.
8 Customer Training
The Engineering Technical Training group (ETT)
provides training for VLS users. ETT normally gives
courses at Chelmsford, Massachusetts. Courses can also
be taught at a site by special arrangement with ETT.
Courses that are appropriate for VLS users include the
following:
o The Site Rep Training course presents an overview
of VLS, including material from the VLS User
Course. Moreover, it provides specialized job
training for local site support people, addressing
such issues as defining and reporting problems.
o The VLS User Course is an introductory course for
experienced board designers who are new to VLS.
This course is a hands-on workshop. It includes
lecture-demonstrations by experienced board
designers and trainers, as well as labs in which
the students use VLS on an actual board design.
o Read-Only/Graphics shows manufacturing and field
service sites who have read-only kits how to use
VLS for reviewing designs and drawings.
o Introduction to PC Board Design presents basic
concepts of board design, using both manual and
CAD techniques. For new designers, this is a
prerequisite to the VLS User Course.
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o Introduction to VLS gives a brief overview of
VLS. This course is appropriate for managers and
supervisors of groups that use VLS.
o VLS Software Differences is a course that is given
each time a new version of VLS is released. This
course presents the new features of the release
and shows how to use these features in designing
boards.
o The VAX/VMS User Course presents the basics for
people who are new to VMS.
o Customized courses are also available. If a site
has a unique need, ETT will be happy to discuss the
design of an appropriate course.
Each new site receives a training package consisting
of the Site Rep Training and either the VLS User
Course or Read-Only/Graphics.
9 System Configuration
VLS runs under the VMS operating system. It can be
run on virtually any VAX, and the graphics can be
displayed on a number of devices.
Hardware. To run VLS, you need the following hardware:
o CPU: VAX or MicroVAX
o Graphics devices:
- High-performance
LEX 3400 or 90
METHEUS 3610 or 530
- Medium-performance
VAXstation II/GPX
- Low-performance
VT330 or 340
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VT240 or 241
VT125
o Input device: mouse, puck, or stylus
o Graphics tablet: GTCO
Software. There are three VLS kits available:
o Design kit - This is the kit for design centers. It
includes all the software needed to design boards
using VLS.
o Development kit - Sites that want to customize
software can add this kit to the design kit. The
development kit contains all the source code for
the programs in the design kit.
o Read-only kit - Manufacturing and field service
sites can use this kit as a cost-effective way to
examine board designs. The read-only kit contains
all the graphic display software plus reporting
applications.
To learn more about VLS, including details of support,
system configuration, and current prices, contact one
of the following people:
Fred Haefner CADSE::HAEFNER DTN 287-3383
Carol Breest CADSE::BREEST DTN 287-3300
_______________________________________________________
LEXIDATA and LEX 90 are trademarks of Adage, Inc.
METHEUS is a trademark of Metheus, Inc.
Copyright (c) 1988 by Digital Equipment Corporation
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