Ngspice F.A.Q.Version 1.5 (rework-18 release) Maintained by Paolo Nenzi Last update: 5-11-2008 This document contains the Frequently Asked Questions (and Answers) for ngspice project. __________________________________________________________________________ Table of Contents 1. INTRODUCTION AND GENERAL INFORMATION 1.1 What is ngspice? 1.2 What is tclspice ? 1.3 Why resurrecting Berkeley's Spice? 1.4 What is the project's goal? 1.5 What you are going to do? 1.6 Legal issues 1.7 What mailing lists exist for ngspice? 1.8 Are the mailing lists archived anywhere? 1.9 What newsgroups exist for ngspice? 1.10 Where can I get a copy of ngspice? 1.11 Where should I look on the World Wide Web for ngspice stuff? 1.12 Where should I look on the World Wide Web for Spice documentation? 2. DEVELOPMENT 2.1 What is the current version? 2.2 What are the latest features in the current release? 2.3 What does it look like? 2.4 Who are the authors of ngspice? 2.5 How can I report a bug/request for a feature? 2.6 How can I join the development? 3. SOLUTIONS TO COMMON MISCELLANEOUS PROBLEMS 3.1 What systems are supported? 3.2 I get errors when I try to compile the source code, why? 3.3 This document didn't answer my question. Where else can I look for an answer? 4. ADMINISTRATIVE INFORMATION AND ACKNOWLEDGEMENTS 4.1 Feedback 4.2 Formats in which this FAQ is available 4.3 Authorship and acknowledgements 4.4 Disclaimer and Copyright ______________________________________________________________________ 1. INTRODUCTION AND GENERAL INFORMATION 1.1 What is ngspice ? Ngspice is a mixed-level/mixed-signal circuit simulator based on three open source software packages: Spice3f5, Cider1b1 and Xspice: - Spice3 is a widely used circuit simulator. It was developed by the University of California at Berkeley (UCB), by "a cast of thousand" (as they say) initially under the guide of Donald O. Peterson. - Cider is a mixed-level simulator that already includes Spice3f5 and adds a device simulator to it: DSIM. Cider couples the circuit level simulator to the device simulator to provide greater simulation accuracy (at the expense of greater simulation time). Critical devices can be described with technology parameters (numerical models) and non critical ones with the original spice's compact models. - Xspice is an extension to Spice3 that provides code modeling support and simulation of digital components through an embedded event driven algorithm. The NG prefix has lot of meanings: Next Generation, New Good, etc. Choose or invent the one you prefer. The heart of the project is the ngspice program. 1.2 What is tclspice ? Tclspice is a circuit simulator that embeds ngspice and provides a tcl/tk interface to the user. Tclspice is both a batch and interactive simulator and a building block for simulator applications. Analyses can be run from a tcl script and vector plotted or post processed using tcl or a small GUI can be built to analyze a circuit or a set of circuits. Tclspice is obtained compiling ngspice activating an additional option. 1.3 Why resurrecting Berkeley's Spice? Berkeley's Spice can be considered the father of most circuit simulators available today. It is an old but still good piece of software, it may not be the fastest or the most reliable but it's free, it's available in source code and most of the electrical simulators inherited it's syntax. Spice3 is based on proven numerical algorithms (most commercial implementations have only strengthened them), implements most of the models for MOSFET submicron design and has a powerful set of analyses. The readily availability of its source code in the past made this simulator the de-facto standard. 1.4 What is the project's goal? Ngspice is both a maintenance and enhancement project. It is a maintenance project because it aims to provide the free EDA community the best spice3 simulator available. This means fixing bugs, adding new features but always in the spice3 framework. Achieving compatibility with commercial spice based simulators and provide users the latest devices models are important goals of the project. Improvements in the postprocessing (data handling capabilities) and user interface are other goals. 1.5 What you are going to do? An official roadmap for ngspice was never drawn. Contributions made by developers drive ngspice development and the roadmap is built day by day by developers writing on the lists. Ngspice development activity can be summarized in 3 points: + Compatibility: Ngspice should be compatible with commercial products, thus allowing people to use the netlist generated for such tools. As most of the commercial simulators avaiable tracked each other in netlist language, this should not be an impossible task. The most important goal here is to provide a reliable support for model libraries coming from foundries. + Compact models: The interest in using ngspice is intimately connected to the available models. To provide the latest models available for active and passive devices is a fundamental goal of the project. In this direction we are integrating ADMS model compiler into ngspice. + Documentation: Commercial simulators come with very good manuals containing tutorials, description of models equations, example of use, suggestions, etc. Spice came with little documentation. The Spice3f manual, available on the Internet has been used as the basis for the new manual. It will be constantly improved during ngspice development and integrated with the documentation accompanying Xspice and Cider. This is a very time consuming task and probably the documentation will always be left slightly behind. 1.6 Legal issues Ngspice, starting from release rework-18 is released under BSD/LGPL license. Part of the code are covered by other compatible licenses: spice3 and cider are BSD, xspice is Public Domain and TCLSPICE is LGPL and the copyright is of their respective owners (need to write better) 1.7. What mailing lists exist for ngspice? There are two general mailing lists dedicated to the ngspice project. Users mailing list: <ngspice-users@lists.sourceforge.net> This list is for ngspice users, examples, problems, bug reports and general discussion on ngspice can be sent here. Developers mailing list: <ngspice-devel@lists.sourceforge.net> The list dedicated to ngspice development. Developers shold subscribe here, to follow the program development. May be used to send patches, and technical discussion on ngspice. Send an empty message to the following addresses to get information on subscription. <ngspice-users-help@lists.sourceforge.net> <ngspice-devel-help@lists.sourceforge.net> 1.8. Are the mailing lists archived anywhere ? Yes, the lists are archived. There are two places where to look for archives. The project started on the IEEE Central and South Italy web server and then moved to sourceforge. Sourceforge provides an archiving service that cam be accessed via the summary page: http://sourceforge.net/projects/ngspice (look for the "Lists" link). Old messages from the pre-sourceforge age are available at: http://ngspice.sourceforge.net/lists.html 1.9. What newsgroups exist for ngspice? There is no ngspice specific newsgroup. Anyway ngspice threads appear on newsgroups dedicated to circuit simulation and electronic design. An (incomplete) list is: sci.electronics.cad comp.lsi.cad 1.10. Where can I get a copy of ngspice? You can download ngspice from: http://sourceforge.net/projects/ngspice 1.11. Where should I look on the World Wide Web for ngspice stuff? Look at the official Ngpice Web Page: http://ngspice.sourceforge.net 1.12. Where should I look on the World Wide Web for Spice documenta- tion? There are a lot of Internet sites that have information on spice, the best way is to point to your preferred search engine. Some interesting sites are: Pages on Spice: http://bwrc.eecs.berkeley.edu/Classes/IcBook/SPICE/ http://embedded.eecs.berkeley.edu/pubs/downloads/spice/index.htm Xspice Page: http://users.ece.gatech.edu/~mrichard/Xspice Cider Page: http://embedded.eecs.berkeley.edu/pubs/downloads/cider/index.htm 2. DEVELOPMENT 2.1. What is the current version? The latest version released is: * ngspice-rework-18 (released on 1/12/2008) 2.2. What are the latest features in the current release? New features: + Support for .lib and .param statements + Improved netlisting capabilites to support more complex model cards + Global net names + Mosfet model binning Bug fixes: + Fixes in the control language 2.3. What does it looks like? Ngspice, as the original Spice3 (and Xspice and Cider) is a command line simulator. 2.4. Who are the authors of ngspice? The development is open to anyone who wish to contribute. If the original Spice3 was made with the contribution of "a cast of thousand", ngspice can only increase that number. An incomplete list of contributor makes the "acknowledgements" page of ngspice documentation. 2.5. How can I report a bug/request for a feature? The ngspice summary page (hosted on Sourceforge) has bug-reporting, feature-request and bugs trackers. You can use them or subscribe to mailing lists and post there. The latter is preferred since almost all developers/contributors read the lists but only a few of them use trackers. 2.6. How can I join the development? To join the development just code the feature you want to add and send your patch in the mailing list. Before you start coding check the latest development release of ngspice from our CVS. It might be that your feature has already been implemented. There is no bureaucracy here. 3. SOLUTIONS TO COMMON MISCELLANEOUS PROBLEMS 3.1. What systems are supported? Ngspice is written in C, and uses some GNU extensions, then you need a GNU C compiler and a UNIX environment to compile it. Ngspice can be compiled under Windows using the mingw or cigwin environment. In the future a compatibility table will be written. 3.2. I get errors when I try to compile the source code, why? This is a one-million-euros question :). Write a mail to the user's list describing the problem and providing information on the type of hardware, the flavour of operating system. 3.3. This document didn't answer my question. Where else can I look for an answer? Read old messages from the mailing list archive, search the web site or read the docs. Upgrade to the latest version of ngspice, many problems are fixed in the new versions. If you still can't find an answer, post your question to the mailing lists. 4. ADMINISTRATIVE INFORMATION AND ACKNOWLEDGEMENTS 4.1. Feedback Send your comments about this F.A.Q. to: Paolo Nenzi <p.nenzi@ieee.org>. Send your comments about ngspice to: Paolo Nenzi <p.nenzi@ieee.org>. 4.2. Formats in which this FAQ is available This document is available only in ASCII format in the ngspice source package. 4.3. Authorship and acknowledgements Parts of the questions and answers are originate from Paolo Nenzi. 4.4. Disclaimer and Copyright This document is provided as is. The information in it is not warranted to be correct: you use it at your own risk.