In a number of cases of simulation of variable time waveforms the PWL format is used in SPICE based circuit simulators. If the statement is really short with only two or three pairs of values it can be input manually by hand. However, if the number of (time, value) pairs is large then a resource is required that can generate the PWL waveform using some kind of CAD program. Signal Processing Group Inc., recently released a related script in C++ that can be used for this task. It consists of an input file generated from a text resource ( in this case a MATLAB file, also included)which has a 1,0 vector of numbers. 1,0 of course representing logic high and logic low. This file can be as long as needed. This file is input into the C++ program which converts the file into a PWL statement for the simulator. To access this program please visit http://www.signalpro.biz and go to “Register for free stuff” The program can be downloaded free of cost through this gateway. The program has been tested using Windows XP.To run it on a different platform may require re-compilation and build.
IC design: Generate a PWL signal from a text input