Using Sim+ With Various EDA Packages

Sim+ have been tested with three EDA / Schematic capture packages, the packages tested are:

Sim+ uses the netlist file generated by these EDA packages as an input. Currently Sim+ supports WIRELIST and TANGO netlist formats, therefore it should be possible to use any other EDA package that produces one of these netlist formats as a front-end to Sim+ as well.

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Using Sim+ with OrCAD SDT
Using Sim+ with MicroSim Design Lab
Using Sim+ with Aldec Active-CAD

Using Sim+ with OrCAD SDT

It was found that the best netlist format for interfacing Sim+ with OrCAD SDT is 'wirelist' format. OrCAD SDT poses virtually no limits on net names and pin names, which makes life very easy.

Sim+ can handle 'single-pin' nets as constant value inputs to it's blocks. for example, if the user wishes to pass a real signal through a constant gain (say 1.3) 'amplifier' , all he/she has to do is connect that signal to one input of a real signal multiplier block ('mult_r') , and draw a short wire labeled 1.3 to the other input of the multiplier.
This also works with expressions, so labeling a net '2.2+PI/2.0' will also work - provided that PI (3.14...) is defined in one of the header files.

Using Sim+ with MicroSim Design Lab version 8

The Design Lab package tested was the evaluation package, which does not support 'wirelist' format netlist output, therefore, only 'tango' format was tested.

There are two main issues the user should be aware of when using Design Lab ver.8 with 'tango' format as a front-end to Sim+:

  1. Design Lab does not include 'single-pin' nets in the netlist, therefore assigning constant values to inputs isn't as simple as in some of the other packages. However, there is a workaround for this problem: the 'stub' symbol (included in the symbol library for MicroSim Design Lab) may be connected as a second 'dummy' input to the constant-value net, this will cause Design Lab to report the net in the netlist, and will not affect the code generated by the Sim+ translator.
  2. While generating 'tango' format netlist, Design Lab converts the 'dot' (.) character in net labels to an 'underscore' (_), this makes it inconvenient to specify constant real values to nets.
    for example: if you labeled a net '3.2e7' it will be named '3_2e7' in the tango netlist file.
    Possible workarounds are:
    A. use an AWK or PERL script to translate underscores to dots. (risky!)
    B. use names for constant value nets, and the #define values for these names in an external header file ('user.h' etc.)

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Using Sim+ with Aldec Active-CAD 2.5

The Active-CAD version (evaluation package) tested with Sim+ does not support 'wirelist' format export, therefore only 'tango' format was tested. Interface with Active-CAD is pretty smooth except for one minor issue -
Active-CAD limits pin number length to four characters (which do not have to necessarily be digits!), It is the pin numbers and not the pin names that appear in the tango netlist, so that the user is practically limited to pin names that are no longer than four characters. In many Sim+ blocks this does not pose a problem at all, since all input and output names are shorter than four characters to begin with, however, some of the blocks (*.df files), which were originally defined with longer pin names may not be used as-is with Active-CAD.
The solution for this is fairly simple: existing block definition files that have long pin names may be copied to a new sub-directory (in the df1400.zip : 'simplus\df_sn') and edited so that all problematic i/o names are replaced with shorter names. Then the 'DFPATH' line in the Sim+ configuration file should be modified to include the path to the new subdirectory BEFORE the older directories, that way, there is no need to modify or delete existing block definition files, Sim+ will first look for the *.df file in the new subdirectory, and if it does not find it there, Sim+ will go on and look for the *.df file in subsequent directories in DFPATH.

Note: an appropriate configuration file and a subdirectory with 'short i/o names' block definition files (for some of the blocks) for use with Active-CAD 2.5 is already included in the distribution archives.

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updated: Jan 16, 1998.