EDIF is a vendor-neutral format in which to store Electronic netlist
Netlist
The word netlist can be used in several different contexts, but perhaps the most popular is in the field of electronic design. In this context, a "netlist" describes the connectivity of an electronic design....
s and schematics. It was one of the first attempts to establish a neutral data exchange format for the electronic design automation
Electronic design automation
Electronic design automation is a category of software tools for designing electronic systems such as printed circuit boards and integrated circuits...
(EDA) industry. The goal was to establish a common format from which the proprietary formats of the EDA systems could be derived. When customers needed to transfer data from one system to another, it was necessary to write translators from one format to other. As the number of formats (N) multiplied, the translator issue became an N-squared problem. The expectation was that with EDIF the number of translators could be reduced to the number of involved systems.
Daisy Systems Corporation incorporated in 1981 in Mountain View, California, was a computer-aided engineering, CAE, company, a pioneer in the Electronic design automation industry....
Mentor Graphics, Inc is a US-based multinational corporation dealing in electronic design automation for electrical engineering and electronics, as of 2004, ranked third in the EDA industry it helped create...
Motorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...
National Semiconductor was an American semiconductor manufacturer, that specialized in analog devices and subsystems,formerly headquartered in Santa Clara, California, USA. The products of National Semiconductor included power management circuits, display drivers, audio and operational amplifiers,...
Tektronix, Inc. is an American company best known for its test and measurement equipment such as oscilloscopes, logic analyzers, and video and mobile test protocol equipment. In November 2007, Tektronix became a subsidiary of Danaher Corporation....
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
established the EDIF Steering Committee in November 1983. Later Professor Hilary Kahn (1943-2007) from the University of Manchester
University of Manchester
The University of Manchester is a public research university located in Manchester, United Kingdom. It is a "red brick" university and a member of the Russell Group of research-intensive British universities and the N8 Group...
joined the team and lead the development from version EDIF 2 0 0 till the final version 4 0 0.
Syntax
The general format of EDIF involves using parentheses to delimit data definitions, and in this way it superficially resembles Lisp. The basic tokens of EDIF 2.0.0 were keywords (like library, cell, instance, etc.), strings (delimited with double quotes), integer numbers, symbolic constants (e.g. GENERIC, TIE, RIPPER for cell types) and "Identifiers", which are reference labels formed from a very restricted set of characters.
EDIF 3.0.0 and 4.0.0 dropped the symbolic constants entirely, using keywords instead.
So, the syntax of EDIF has a fairly simple foundation. A typical EDIF file looks like this:
(edif fibex (edifVersion 2 0 0)
(edifLevel 0) (keywordMap (keywordLevel 0))
(status (written (timeStamp 1995 1 1 1 1 1) (program "xxx" (version "v1"))))
(library xxx (edifLevel 0)
(technology (numberDefinition (scale 1 (e 1 -6) (unit distance))))
(cell dff_4 (cellType generic)
(view view1 (viewType netlist)
(interface
(port aset (direction INPUT))
(port clok (direction INPUT))
...
(cell yyy (cellType generic)
(view schematic_ (viewType netlist)
(interface
(port CLEAR (direction INPUT))
(port CLOCK (direction INPUT)) ... )
(contents
(instance I_36_1 (viewRef view1 (cellRef dff_4)))
(instance (rename I_36_3 "I$3") (viewRef view1 (cellRef addsub_4)))
...
(net CLEAR
(joined
(portRef CLEAR)
(portRef aset (instanceRef I_36_1))
(portRef aset (instanceRef I_36_3))))
...
EDIF 2 0 0
The first "real" public release of EDIF was version 2 0 0, which was approved in March 1988 as the standard ANSI/EIA-548-1988. It is published in a single volume. This version has no formal scope statement but what it tries to capture is covered by the defined viewTypes:
BEHAVIOR to describe the behavior of a cell
DOCUMENT to describe the documentation of a cell
GRAPHIC to describe a dumb graphics and text representation of displayable or printable information
LOGICMODEL to describe the logic-simulation model of the cell
MASKLAYOUT to describe an integrated circuit layout
NETLIST to describe a netlist
PCBLAYOUT to describe a printed circuit board
SCHEMATIC to describe the schematic representation and connectivity of a cell
STRANGER to describe an as yet unknown representation of a cell
SYMBOLIC to describe a symbolic layout
The industry tested this release for several years, but finally only the NETLIST view was the one widely used and some EDA tools are still supporting it today for EDIF 2 0 0.
To overcome problems with the main 2 0 0 standard several further documents got released:
EDIF Monograph Series, Volume 2, EDIF Connectivity, EIA/EDIF-2, June 1989
Using EDIF 2 0 0 for schematic transfer, EIA/EDIF/AG-1, July 1989
Documentation from Hilary J. Kahn, Department of Computer Science, University of Manchester
EDIF 2 0 0, An Introductory Tutorial", September 1989
EDIF Questions and answers, volume one, November 1988
EDIF Questions and answers, volume two, February 1989
EDIF Questions and answers, volume three, July 1989
EDIF Questions and answers, volume four, November 1989
EDIF Questions and answers, volume five, June 1991
EDIF 3 0 0
Because of some fundamental weaknesses in the 2 0 0 release a new not compatible release 3 0 0 was released in September 1993, given the designation of EIA
Electronic Industries Alliance
The Electronic Industries Alliance was a standards and trade organization composed as an alliance of trade associations for electronics manufacturers in the United States. They developed standards to ensure the equipment of different manufacturers was compatible and interchangeable...
The American National Standards Institute is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international...
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
designations. It is published in 4 volumes. The main focus of this version were the viewTypes NETLIST and SCHEMATIC from 2 0 0. MASKLAYOUT, PCBLAYOUT and some other views were dropped from this release and shifted for later releases because the work for these views was not fully completed.
The International Electrotechnical Commission is a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology"...
as IEC 61690-1
EDIF 4 0 0
EDIF 4 0 0 was released in late August 1996, mainly to add "Printed Circuit Board" extensions (the original PCBLAYOUT view) to EDIF 3 0 0. This more than doubled the size of EDIF 3 0 0, and is published in HTML format on CD.
EDIF 4 0 0 is available from the International Electrotechnical Commission as IEC 61690-2
Problems with 2 0 0
To understand the problems users and vendors encountered with EDIF 2 0 0, one first has to picture all the elements and dynamics of the electronics industry. The people who needed this standard were mainly design engineers, who worked for companies whose size ranged from a house garage to multi-billion dollar facilities with thousands of engineers. These engineers worked mainly from schematics and netlists in the late 1980s, and the big push was to generate the netlists from the schematics automatically. The first suppliers were Electronic Design Automation vendors (e.g., Daisy, Mentor, and Valid formed the earliest predominating set). These companies competed vigorously for their shares of this market.
One of the tactics used by these companies to "capture" their customers was their proprietary databases. Each had special features that the others did not. Once a decision was made to use a particular vendor's software to enter a design, the customer was ever after constrained to use no other software. To move from vendor A's to vendor B's systems usually meant a very expensive re-entry of almost all design data by hand into the new system. This expense of "migration" was the main factor that locked design engineers into using a single vendor.
But the "customers" had a different desire. They saw immediately that while vendor A might have a really nice analog simulation environment, vendor B had a much better PCB or silicon layout auto-router. And they wished that they could pick and choose amongst the different vendors.
EDIF was mainly supported by the electronics design end-users, and their companies. The EDA vendors were involved also, but their motivation was more along the lines of wanting to not alienate their customers. Most of the EDA vendors produced EDIF 2 0 0 translators, but they were definitely more interested in generating high-quality EDIF readers, and they had absolutely no motivation at all to write any software that generated EDIF (an EDIF Writer), beyond threats from customers of mass migration to another vendor's software.
The result was rather interesting. Hardly any software vendor wrote EDIF 2 0 0 output that did not have severe violations of syntax or semantics. The semantics were just loose enough that there might be several ways to describe the same data. This began to be known as "flavors" of EDIF. The vendor companies did not always feel it important to allocate many resources to EDIF products, even if they sold a large number of them. There were several stories of active products with virtually no-one to maintain them for years. User complaints were merely gathered and prioritized. The harder it became to export customer data to EDIF, the more the vendors seemed to like it. Those who did write EDIF translators found they spent a huge amount of time and effort on generating sufficiently powerful, forgiving, artificially-intelligent readers, that could handle and piece together the poor-quality code produced by the extant EDIF 2 0 0 writers of the day.
In designing EDIF 3 0 0, the committees were well aware of the faults of the language, the calumny heaped on EDIF 2 0 0 by the vendors and the frustration of the end users. So, to tighten the semantics of the language, and provide a more formal description of the standard, the revolutionary approach was taken to provide an information model for EDIF, in the information modeling language EXPRESS. This helped to better document the standard, but was done more as an afterthought, as the syntax crafting was done independently of the model, instead of being generated from the model. Also, even though the standard says that if the syntax and model disagree, the model is the standard, this is not the case in practice. The BNF description of the syntax is the foundation of the language inasmuch as the software that does the day-to-day work of producing design descriptions is based on a fixed syntax. The information model also suffered from the fact that it was not (and is not) ideally suited to describing EDIF. It does not describe such concepts as name spaces very well at all, and the differences between a definition and a reference is not clearly describable either. Also, the constructs in EXPRESS for describing constraints might be formal, but constraint description is a fairly complicated matter at times. So, most constraints ended up just being described as comments. Most of the others became elaborate formal descriptions which most readers will never be able to decipher, and therefore may not stand up to automated debugging/compiling, just as a program might look good in review, but a compiler might find some interesting errors, and actually running the program written might find even more interesting errors. (Additionally, analogous EXPRESS compilers/executors didn't exist when the standard was written, and may not still exist today!)
Solutions to EDIF 2 0 0 problems
The solution to the "flavor" problem of EDIF 2 0 0 was to develop a more specific semantic description in EDIF 3 0 0 (1993). Indeed, reported results of people generating EDIF 3 0 0 translators was that the writers were now much more difficult to get right, due to the great number of semantic restrictions, and the readers are comparatively trivial to develop.
The solution to vendor "conflict of interest" was neutral third-party companies, who could provide EDIF products based on vendor interfaces. This separation of the EDIF products from direct vendor control was critical to providing the end-user community with tools that worked well. It formed naturally and without comment. Engineering DataXpress was perhaps the first such company in this realm, with Electronic Tools Company seeming to have captured the market in the mid to late 1990s. Another dynamic in this industry is EDIF itself. Since they have grown to a rather large size, generating readers and writers has become a very expensive proposition. Usually the third-party companies have congregated the necessary specialists and can use this expertise to more efficiently generate the software. They are also able to leverage code sharing and other techniques an individual vendor could not. By 2000, almost no major vendor produced its own EDIF tools, choosing instead to OEM
Original Equipment Manufacturer
An original equipment manufacturer, or OEM, manufactures products or components that are purchased by a company and retailed under that purchasing company's brand name. OEM refers to the company that originally manufactured the product. When referring to automotive parts, OEM designates a...
third-party tools.
Since the release of EDIF 4 0 0, the entire EDIF standards organisation has essentially dissolved. There have been no published meetings of any of the technical subcommittees, the EDIF Experts group, etc. Most of the individuals involved have moved on to other companies or efforts. The newsletter was abandoned, and the Users' Group no longer holds yearly meetings. EDIF 3 0 0 and 4 0 0 are now ANSI
American National Standards Institute
The American National Standards Institute is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international...
The International Electrotechnical Commission is a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology"...
and European (EN) standards. EDIF Version 3 0 0 is IEC/EN 61690-1, and EDIF Version 4 0 0 is IEC/EN 61690-2.
EDIF Descendants
LKSoft took concepts from EDIF 2 0 0 to create a proprietary data format with the default extension ".cam" for their CircuitCAM system offered by LPKF Laser & Electronics AG
LPKF Laser & Electronics AG
LPKF Laser & Electronics AG is a German-based equipment manufacturer supplying the electronics industry. Although LPKF focuses mainly on PCB prototyping and micromachining solutions for SMT stencils, the company also offers laser plastic welding systems and precision drives, as well as laser...
. To efficiently work on EDIF like formats LKSoft has developed the EDIF Procedural Interface, an API for the C programming language
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
is a Japanese multinational corporation, specializing in software and consulting services for end-to-end electrical and electronic engineering. Zuken came into existence as a pioneer in the development of CAD systems in Japan to contribute to electronics manufacturing...
, formerly Racal-Redac Ltd., took concepts from the early EDIF 4 0 0 development to create a new proprietary format called CADIF for their Visula PCB-CAD system. This format is also widely used by 3rd party vendors.
ISO 10303 is an ISO standard for the computer-interpretable representation and exchange of product manufacturing information. Its official title is: Automation systems and integration — Product data representation and exchange...
, practically inherited all of the EDIF 4 0 0 functionality except for schematics.
External links
BYU EDIF Tools A Java framework for parsing/manipulating EDIF files, developed and maintained by BYU
BYU
-Education:* Brigham Young University, a university located in Provo, Utah, USA administered by The Church of Jesus Christ of Latter-day Saints.**BYU Salt Lake Center, a satellite center in Salt Lake City, Utah, USA...
