diff --git a/README.XSPICE b/README.XSPICE index c527d4846..cbda7a84e 100644 --- a/README.XSPICE +++ b/README.XSPICE @@ -1,20 +1,58 @@ This document is covered by the Creative Commons Attribution Share-Alike (CC-BY-SA) v4.0. . -*************** XSPICE improvements ****************************************** +*************** Verilog A Device models in ngspice ****************************************** 1 Introduction -Memory management of event driven (digital) XSPICE needs improvements. +New compact device models today are released as Verilog-A code. Ngspice applies ADMS to +translate the va code into ngspice C syntax. Currently a limited number of Verilog-A models is +supported: HICUM level0 and level2 (HICUM model web page), MEXTRAM (MEXTRAM +model web page), EKV (EKV model web page) and PSP (NXP PSP web site). -2 Reduce memory for Ad and DA bridges +2 ADMS -The ad bridge (type 78) and the DA bridge (type 79) used to consume a lot -of memory, because for each time step a new state had been created and -added to the state linked list. -During evaluation, however, only the two last stated are used. Therefore the -following code deletes a state from the head of the list, when there are more than -two states. -FIXME: this could be done more efficiently (e.g. by not mallocing new states), -but one carefully has to update relevant indices. +ADMS is a code generator that converts electrical compact device models specified in high-level +description language into ready-to-compile C code for the API of spice simulators. Based on +transformations specified in XML language, ADMS transforms Verilog-AMS code into other +target languages. Here we use it to to translate the va code into ngspice C syntax. +To make use of it, a set of ngspice specific XML files is distributed with ngspice in ngspice\ +src\spicelib\devices\adms\admst. Their translation is done by the code generator executable +admsXml (see below). + + +3 How to integrate a Verilog-A model into ngspice + +3.1 How to setup a *.va model for ngspice + +Unfortunately most of the above named models’ licenses are not compatible to free software +rules as defined by DFSG. Therefore since ngspice-28 the va model files are no longer part of +the standard ngspice distribution. They may however be downloaded as a tar.gz archive from the +ngspice-30 file distribution folder. After downloading, you may expand the zipped files into +your ngspice top level folder. The models enable dc, ac, and tran simulations. Noise simulation +is not supported. +Other (foreign) va model files will not compile without code tweaking, due to the limited +capabilities of our ADMS installation. + + +3.2 Adding admsXml to your build environment + +The actual admsXml code is maintained by the QUCS project and is available at GitHub. +Information on how to compile and install admsXml for Linux or Cygwin is available on the +GitHub page. For MS Windows users admsXml.exe is available for download from +https://sourceforge.net/projects/mot-adms/. You may copy admsXml.exe to your MSYS2 setup +into the folder msys64\mingw64\bin, if 64 bit compilation is intended. +More information, though partially outdated, is obtainable from the ngspice web pages +(http://ngspice.sourceforge.net/admshowto.html) and from README-old.adms. + + +3.3 Compile ngspice with ADMS + +In the top level ngspice folder there are two compile scripts compile_min.sh and compile_linux.sh. +They contain information how to compile ngspice with ADMS. You will have to run autogen.sh +with the adms flag +./autogen.sh --adms +In addition you have to add --enable-adms to the ./configure command. Please check chapter +32.1 of the ngspice manual for perequisites and further details. +Compiling ngspice with ADMS with MS Visual Studio is not supported.