PyQSPICE: A Python scripting interface for QSPICE

QSPICE
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For those of us who are Python users, I would like to highlight a new tool called PyQSPICE. It works with QSPICE’s command-line interface to load QSPICE simulation results into memory for plotting in Python.

This is an open-source project hosted on GitHub. It is not supported by the QSPICE team.

GitHub - Qorvo/PyQSPICE: Python Interface for QSPICE

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Hi Jeff.

For me this is very interesting information. Maybe I can get EAGLE to show an output window for QSpice instead of a PCB.

Thank you very much. Tom

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Hi Jeff

My colleague told me that there is another :thinking: “PyQSPICE”.
GitHub - nunobrum/PyQSPICE: Python Library to operate with QSpice and read simulation output files
The author is the same person who wrote “PyLTspice”.
Is this the same one you mentioned?

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They are two different projects. There’s more discussion on the one I mentioned here:

I’m glad there is enough interest in the concept to drive two different developments!

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Hi,

I’ve got an offline DM Q&A regarding this Python module and here’s summary which may help someone who gets the same questions.

Q:: Any good documentation?
A:: Sorry…not yet.

  • QuickStart has quick comments before lines.
  • The main module has an explanation in front of each method.

Q:: How to tweak a parameter, run a sim and repeat/loop?
A:: This example is running 2 sims from one next list by changing the netlist “.cir” file with Python regular expression “re” module.

Q:: Why “SJIS” encoding, in the Python module?
A:: See this discussion. The QSPICE uses “Latin-1 Supplement” and many file-encoding judgement routines (checked a couple of standalone encoding detection programs) think it “Shift JIS”, with a probability view point. Just to avoid Python error message, I use the “SJIS” encoding and I know I’m dealing with a file of “Latin-1 Supplement”.

masashi

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PyQSPICE is very good and I have used it already.
How do I print the dc operating points if I am using PyQSPICE?? I do not see that function in the PyQSPICE class and was hoping if you could please help with that? It will be a good starting point to see dc operating points of all nodes (and currents)
before the PSRR circuit is simulated (or any other AC sim is triggered)

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I run a quick trial and I see PyQSPICE can support your “.OP” needs.

I’m on the road and please wait for me next week :slight_smile:
I’ll delete this post when I update PyQSPICE for the “.OP”, by replacing my post with the detail how to handle “.OP” on PyQSPICE.

I believe I made an over commitment, it’s the Thanks-Giving week here in USA…Within Nov, I’ll try to get it updated for “.OP”.

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thank you masashi! I look forward to your uprate on how to use .op within PyQSPICE and getting a text file with outputs printed for the operating point (just like what one can see in the terminal).

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Please check updated ver.2023.11.29 PyQSPICE.

  • It supports .OP result reading. To make this happens, PyQSPICE now reads “.cir” netlist and extract nodes and elements. Not all elements implemented (logic gates, AD/DA converters), voltage nodes completely sandwiched by those elements will be ignored…for now.
  • Plot setting lines are consolidated into a method and now we can make our main code clean.
    Only the code of “tests/50_OP” is clean for plotting, will update older “tests” examples step-by-step.
  • The example “tests/50_OP” is showing simple results but it is reading more info from the “.OP” run. Please try “print(df)” to see all the info this new version PyQSPICE reading.

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Updated to Ver.2023.12.11,
by improving plotting codes,
by supporting examples in my coming Microwave Journal articles.

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Can you plot signal buses that out be in the form of out[3:0]? I having been playing with the verilog functionality in qspice and not seeing a nice way to display buses in qspice. The ability to display buses in a similar way as modelsim would be nice that could interpret buses in decimal, binary or hex

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Hi!

Interesting subject. As I love software programming, I want to do something here (but no promise :stuck_out_tongue: ).
May I ask couple of questions.

  • Do you want to have a waveform browser of zoom in/out, adding/deleting waveforms?
    In another word, do you want an advanced GUI waveform viewing software?
  • Or, is it OK to plot a range of waveform you can specify in your Python code?

I guess you want a waveform viewer…

By reading your post, I have these 2 things in my mind.

  1. Just to plot on Matplotlib
  2. To convert the “.qraw” output into another data format of available waveform viewer.
    ==> To all folks reading this thread: any suggestion of waveform viewer software online available at no cost, and its data format open and available? Here, mixed-signal (both analog and digital) waveform viewer.

masashi

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Hi Masashi San,

i used to work using pyqtgraph.
https://www.pyqtgraph.org/

Its very quick and can handle millions of datapoint easily.

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Ideally i would think an interactive window would be preferred. If displaying vector data is not something that native Qspice app is intending to support then I believe a matplotlib approach that can interpret .qraw data in vector form would be awesome. matplotlib has interactive features in their figures. Would this level of interactive features be sufficient?

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==> @rmruthyun
Thanks. As you pointed out, after my last post, I found matplotlib offers decent flavors of interactive functions too. I think that’s enough to navigate / investigate simulation data.

By now, I think I can add a function to handle logic bus.
Just to confirm that you use “boolean” output of “bus label” like below?
This way, I can see how many bits on the port from my Python code.

image

==> @physicboy
Thanks for the link of nice library.
I’m thinking to stay with matplotlib for now until we hit a big roadblock of plotting with matplotlib.
I didn’t check it in detail but anything “Qt” must be pretty and supporting everything GUI programs need (but demanding more coding effort :stuck_out_tongue: ).

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yes I have been using the boolean datatype.

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Release 2024.01.03 · Qorvo/PyQSPICE (github.com)

In the course of digital bus plotting, it’s easy for me to have UTF-8 version of my netlist and I made it automated with the qsch2cir() method.

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A snapshot uploaded below 70_Verilogbus. The main PyQSPICE module / methods are not updated yet but this .ipynb notebook contains flattened code.

image

  • Maybe re-compile needed on your QSPICE schematic window from the cntr.v Verilog file (though I uploaded DLL binary which is working for me).
  • I’m using ipympl module for an interactive plot area on Jupyter Lab.
    Please install it as needed.
  • Once everything’s good, you will have a plot area (below).
    Mouse hover will show cursor reading of bus value.
  • Lower grid of sine wave is nothing but for mixed signal plotting example :slight_smile:

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  • Interactive procedures on matlab can do bus signal (3:0) stacking / separation…not implemented yet.
  • This mouse reading is slow…no optimization implemented yet.
  • I’m not changing bus value text font size, so a frequently changing bus plot will be messy but zooming into the plot will your label visible.
    I have fragments of codes for “range slider” to zoom in x-axes (= time) but commented out now in the ipynb (not fully working in a pretty manner).
  • I’ll wrap this bus plotting routine as new PyQSPICE method so to make it happen with less user code.