Electric (software)
Encyclopedia
The Electric VLSI
Design System is an EDA
tool written by Steven M. Rubin.
Electric is used to draw schematic
s and to do integrated circuit
layout.
It can also handle hardware description languages such as VHDL and Verilog
.
Electric was distributed as free software
for many years, and is currently part of the GNU project
. The new release of GNU Electric, version 9.01, has been released on Oct 5, 2011 and announced on the info-gnu mailing list. It is written in the Java language and released under the GNU GPL.
(IC) layout.
The system considers integrated circuits to be composed of nodes and arcs.
Nodes are circuit elements such as transistors and contacts.
Arcs connect the nodes.
This style of design is quite different from typical IC layout systems, such as Magic
and Cadence
,
which do IC layout by manipulating polygons on different layers of the wafer.
This powerful design style makes it possible for the designer to run Layout Versus Schematic
(LVS) on layouts which are not yet Design Rule Check (DRC) clean. This is extremely useful during the design process. It also makes it possible for the design tool to back-annotate wire-lengths from a layout to a schematic even if the layout is not yet DRC clean. Finally, because layouts are stored internally as a graph (rather than "paint"), the LVS check is exceptionally fast, often running in under a second on full-chip designs (such as the recent Marina chip). The ability to run LVS near-instantaneously on large designs has a big impact on ease of design.
It has been observed that people with no previous experience in IC layout are comfortable with Electric's unusual style,
but those who have done IC layout on other systems find Electric difficult to use.
One added advantage of the nodes-and-arcs view of a circuit is that it is possible to add layout constraints to the arcs.
There are only a small set of these constraints, but with careful placement, the circuit
can be programmed to stay properly connected when physical changes are made.
Electric supports many different design technologies, for example:
(the earliest internal memo on Electric is dated November 19, 1982; the first published
paper on Electric is
"An Integrated Aid for Top-Down Electrical Design", Proceedings, ICCAD-83, IEEE Computer Society Order No 518, September 1983).
For some time after that, Electric was distributed free of charge to universities and research institutions,
and found widespread international use.
In the mid 1980s, Electric was sold commercially by Applicon
, under the name "Bravo3VLSI".
In 1988, Electric Editor Incorporated was founded, and sold the system commercially.
The company released the source code through the Free Software Foundation
in 1998.
In 2000, Static Free Software was created to manage Electric's distribution.
In September, 2003 the C version of Electric was abandoned,
and the system was translated into the Java
language.
The work was completed in June, 2005. Although the C code is still available,
it is no longer developed or supported.
The new and improved Java code remains free to all users.
Very-large-scale integration
Very-large-scale integration is the process of creating integrated circuits by combining thousands of transistors into a single chip. VLSI began in the 1970s when complex semiconductor and communication technologies were being developed. The microprocessor is a VLSI device.The first semiconductor...
Design System is an EDA
Electronic design automation
Electronic design automation is a category of software tools for designing electronic systems such as printed circuit boards and integrated circuits...
tool written by Steven M. Rubin.
Electric is used to draw schematic
Schematic
A schematic diagram represents the elements of a system using abstract, graphic symbols rather than realistic pictures. A schematic usually omits all details that are not relevant to the information the schematic is intended to convey, and may add unrealistic elements that aid comprehension...
s and to do integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
layout.
It can also handle hardware description languages such as VHDL and Verilog
Verilog
In the semiconductor and electronic design industry, Verilog is a hardware description language used to model electronic systems. Verilog HDL, not to be confused with VHDL , is most commonly used in the design, verification, and implementation of digital logic chips at the register-transfer level...
.
Electric was distributed as free software
Free software
Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...
for many years, and is currently part of the GNU project
GNU Project
The GNU Project is a free software, mass collaboration project, announced on September 27, 1983, by Richard Stallman at MIT. It initiated GNU operating system development in January, 1984...
. The new release of GNU Electric, version 9.01, has been released on Oct 5, 2011 and announced on the info-gnu mailing list. It is written in the Java language and released under the GNU GPL.
Powerful Design Style
Electric has a powerful way of doing integrated circuitIntegrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
(IC) layout.
The system considers integrated circuits to be composed of nodes and arcs.
Nodes are circuit elements such as transistors and contacts.
Arcs connect the nodes.
This style of design is quite different from typical IC layout systems, such as Magic
Magic (software)
Magic is a Very-large-scale integration layout tool originally written by John Ousterhout and his graduate students at UC Berkeley during the 1980s. Magic continues to be popular because it is free , easy to use, and easy to expand for specialized tasks...
and Cadence
Cadence Design Systems
Cadence Design Systems, Inc is an electronic design automation software and engineering services company, founded in 1988 by the merger of SDA Systems and ECAD, Inc...
,
which do IC layout by manipulating polygons on different layers of the wafer.
This powerful design style makes it possible for the designer to run Layout Versus Schematic
Layout versus schematic
The Layout Versus Schematic is the class of electronic design automation verification software that determines whether a particular integrated circuit layout corresponds to the original schematic or circuit diagram of the design.-Background:...
(LVS) on layouts which are not yet Design Rule Check (DRC) clean. This is extremely useful during the design process. It also makes it possible for the design tool to back-annotate wire-lengths from a layout to a schematic even if the layout is not yet DRC clean. Finally, because layouts are stored internally as a graph (rather than "paint"), the LVS check is exceptionally fast, often running in under a second on full-chip designs (such as the recent Marina chip). The ability to run LVS near-instantaneously on large designs has a big impact on ease of design.
It has been observed that people with no previous experience in IC layout are comfortable with Electric's unusual style,
but those who have done IC layout on other systems find Electric difficult to use.
One added advantage of the nodes-and-arcs view of a circuit is that it is possible to add layout constraints to the arcs.
There are only a small set of these constraints, but with careful placement, the circuit
can be programmed to stay properly connected when physical changes are made.
Tools and Technologies
Electric incorporates many synthesis and analysis tools:- Design rule checkingDesign rule checkingDesign Rule Checking or Check is the area of Electronic Design Automation that determines whether the physical layout of a particular chip layout satisfies a series of recommended parameters called Design Rules...
two built-in checkers and two interfaces to industry tools. - Electrical Rule Checking a Well/Substrate checker and an Antenna ruleAntenna effectThe antenna effect, more formally plasma induced gate oxide damage, is an effect that can potentially cause yield and reliability problems during the manufacture of MOS integrated circuits. Fabs normally supply antenna rules, which are rules that must be obeyed to avoid this problem. A violation...
checker. - SimulationSimulationSimulation is the imitation of some real thing available, state of affairs, or process. The act of simulating something generally entails representing certain key characteristics or behaviours of a selected physical or abstract system....
two built-in simulators and interfaces to over a dozen industry tools (SpiceSPICESPICE is a general-purpose, open source analog electronic circuit simulator.It is a powerful program that is used in integrated circuit and board-level design to check the integrity of circuit designs and to predict circuit behavior.- Introduction :Unlike board-level designs composed of discrete...
, VerilogVerilogIn the semiconductor and electronic design industry, Verilog is a hardware description language used to model electronic systems. Verilog HDL, not to be confused with VHDL , is most commonly used in the design, verification, and implementation of digital logic chips at the register-transfer level...
, etc.) - RoutingRouting (EDA)In electronic design, wire routing, commonly called simply routing, is a step in the design of printed circuit boards and integrated circuits . It builds on a preceding step, called placement, which determines the location of each active element of an IC or component on a PCB...
five different routers for various special purposes. - Generators a PLAProgrammable logic arrayA programmable logic array is a kind of programmable logic device used to implement combinational logic circuits. The PLA has a set of programmable AND gate planes, which link to a set of programmable OR gate planes, which can then be conditionally complemented to produce an output...
generator, a cell generator, a pad frame generator, and a ROMRead-only memoryRead-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
generator. - Logical EffortLogical effortThe method of logical effort, a term coined by Ivan Sutherland and Bob Sproull in 1991, is a straightforward technique used to estimate delay in a CMOS circuit...
a tool for analyzing the Logical Effort of a circuit and resizing gates. - LVS (layout vs. schematic) a tool which compares any two representations of a circuit.
- I/O the capability to read and write circuit descriptions in many formats, including CIFCaltech Intermediate FormCaltech Intermediate Form is a file format for describing integrated circuits.CIF provides a limited set of graphics primitives that are useful for describing the two-dimensionalshapes on the different layers of a chip....
, GDSGDSIIGDSII stream format, common acronym GDSII, is a database file format which is the de facto industry standard for data exchange of integrated circuit or IC layout artwork. It is a binary file format representing planar geometric shapes, text labels, and other information about the layout in...
, EDIFEDIFEDIF is a vendor-neutral format in which to store Electronic netlists and schematics. It was one of the first attempts to establish a neutral data exchange format for the electronic design automation industry. The goal was to establish a common format from which the proprietary formats of the EDA...
, DXFAutoCAD DXFAutoCAD DXF is a CAD data file format developed by Autodesk for enabling data interoperability between AutoCAD and other programs....
, and VHDL. It can also interface with other systems, such as EagleEagle (program)EAGLE by Cadsoft is a flexible and expandable EDA schematic capture, PCB layout, autorouter and CAM program widely used since 1988.- Schematic capture :...
, Pads, ECADECAD, Inc.ECAD, Inc., based in Santa Clara, California, was an early vendor of electronic design automation software. The company was best known for its design rule checking product Dracula, but also produced IC layout and PC layout software. Eventually, in a merger with SDA, it became Cadence Design...
, and Sue.
Electric supports many different design technologies, for example:
- CMOSCMOSComplementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
- NMOSNMOS logicN-type metal-oxide-semiconductor logic uses n-type metal-oxide-semiconductor field effect transistors to implement logic gates and other digital circuits...
- BipolarBipolar junction transistor|- align = "center"| || PNP|- align = "center"| || NPNA bipolar transistor is a three-terminal electronic device constructed of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons...
- SchematicSchematicA schematic diagram represents the elements of a system using abstract, graphic symbols rather than realistic pictures. A schematic usually omits all details that are not relevant to the information the schematic is intended to convey, and may add unrealistic elements that aid comprehension...
s - Artwork
History
Electric was written in the C programming language in the early 1980s(the earliest internal memo on Electric is dated November 19, 1982; the first published
paper on Electric is
"An Integrated Aid for Top-Down Electrical Design", Proceedings, ICCAD-83, IEEE Computer Society Order No 518, September 1983).
For some time after that, Electric was distributed free of charge to universities and research institutions,
and found widespread international use.
In the mid 1980s, Electric was sold commercially by Applicon
Applicon
Applicon, Incorporated was one of the first vendors of Computer Aided Design and Manufacturing systems. It was founded in 1969 in Bedford, Massachusetts. During the 1970s and early 1980s, the company had its headquarters and R&D facility in Burlington, MA, while their manufacturing facility was in...
, under the name "Bravo3VLSI".
In 1988, Electric Editor Incorporated was founded, and sold the system commercially.
The company released the source code through the Free Software Foundation
Free Software Foundation
The Free Software Foundation is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement, a copyleft-based movement which aims to promote the universal freedom to create, distribute and modify computer software...
in 1998.
In 2000, Static Free Software was created to manage Electric's distribution.
In September, 2003 the C version of Electric was abandoned,
and the system was translated into the Java
Java (Sun)
Java refers to several computer software products and specifications from Sun Microsystems, a subsidiary of Oracle Corporation, that together provide a system for developing application software and deploying it in a cross-platform environment...
language.
The work was completed in June, 2005. Although the C code is still available,
it is no longer developed or supported.
The new and improved Java code remains free to all users.