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NelSim Software, Inc.

Software Products and Consulting Services for ASIC Development and Verification.


Seamless integration of Python, Perl, and Tk with your Verilog® simulations.

ScriptSim Introduction
PCI Model
Contact Info

Announcement: Version 1.16 was released on April 7, 2009 - including 64-bit simulator support and compatibility fixes for recent python releases.

ScriptSim integrates verilog with scripts (perl and python). Using ScriptSim, verilog can dynamically create script processes, and communicate with those processes by passing any verilog data types to the scripts, including passing perl or python command strings. The scripts can access any verilog data in the design, and can perform the equivalent of any verilog assign: blocking, non-blocking, continuous assign, or force.

Because the scripts run as separate processes, the FULL capability of these languages can be used. Any perl or python module can be imported and used, even modules which create a GUI. The script processes execute in parallel with the simulation, and script errors cannot crash the simulation.

ScriptSim allows rapid development of simulation models. It uses a graphical user interface, creating professional-looking windows for presentation of simulation results in text or graphical formats. It is available as open-source software.

A PCI Bus Functional Model is available which includes multi-master, multi-slave, arbiter, and monitor modules. It is written using ScriptSim.

ScriptSim, including the PCI model, is available for download without charge as open source software. This version is for linux and is compatible with most verilog simulators supporting PLI. Contact the developer for Solaris or Windows versions.

To receive release notifications, send an email to: This announcement list has 1 or 2 postings per month. To unsubscribe, send to:

If you need a professional simulation model quickly, and wish to have access to the source, contact NelSim Software for a cost effective solution

NelSim Software is a new company formed by the developer of ScriptSim. The company's goal is to provide training and support for this product and provide related consulting services. ScriptSim could be ported to other simulators, including VHDL simulators.

Special thanks to Fintronic USA for making their simulator available for this development at an affordable price. Finsim has worked great!