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Import LT-SPICE schematics into DesignSpark PCB? HOW?

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  • Boss .

    Interesting idea, but it doesn't fit in with my current way of working.

    I tend to think of the 'system', break this down to 'functions' and simulate these if I feel the requirement e.g. for a transducer interface So my route is design in a CAD system, but in parallel simulate as required, continue with the CAD design selecting components available via spec and footprint and also availability.

    So although I can see some merit in your idea, I don't see (from my understanding of the SPICE netlist) any huge advantage, but that maybe due to the scope of my normal design work and process. Why not draft a simple schematic in DSPCB, analyse in SPICE and paste the simple sch into the main sch design, that will have far more component details than a SPICE netlist import.

    Look forward to other users opinions, perhaps I'm too biased to the 'old SPICE' with a non-graphical interface?

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  • Andrey Porokhnyuk

    Well, you can not always just export to SPICE and simulate. There are no models for many modern integrated components. You have to simulate with available models (often created by the community), then import the schematics, substitute with actual components and add necessary satellite circuits and wiring. Anyway, it is just an approach, but the thing I do not understand - why the most popular, simple straightforward readable format is not implemented yet? In case of Multisim ,I can understand- NI was always in war with community and common sense. (they follow Apple business model). But why DesignSpark happened to be on the same side?

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  • ffred ffred

    Hi,
    didn't use LT-Spice recently, but if your file is a real netlist, you won't find any program able to import it and give you a schematic.
    a netlist only contain symbols names and information about pins connected, but no information about the graphical construction. all you could eventually obtain is like when you go to the PCB layout, with all the components randomly placed and the rastnet making the link between pins. so all the components and links would be there, but you would have to recreate all the schematic. like when routing a PCB.

    but, if your file contain more information about the schematic construction (is LT-Spice able to read it again and give you a nice schematic ?), maybe you could find a converter to another EDA PCB software (eagle, Altium,...) and then eventually be able to import it in Designspark. but with the different conversions, you will probably loose things...

    ffred

    [Edit] just found two links (from 2013) about importing asc LTSpice files into an old version of Eagle, so should be available in the actual Eagle. if your file is not too big maybe you could import it with the free eagle version and then be able to import the Eagle file in Designspark.. (didn't tried to import Eagle file in Designspark yet, so can't help you more).
    link1 link2

    so it probably means that this ASC file is more than a "simple" netlist..

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  • Andrey Porokhnyuk

    "a netlist only contain symbols names and information about pins "

    All (!) symbols are stored in explicit open and easily recognizable ASCII format in library directory and the path can be easily fed along with schematics. There are totally NO obstacles to importing any spice schematics along with symbols. Either this can be done using natural spice directives defining wiring, or using compressed netlist (can we arrange components ourselves? why not?).

    See the example:

    Netlist:

    XU1 +24 N001 +5 0 Isens 0 INA210

    ^name ^pin1 ^pin2..................^component_name

    Symbol file for INA210:

    PIN -32 80 NONE 0
    PINATTR PinName IN+
    PINATTR SpiceOrder 1
    PIN -32 48 NONE 0
    PINATTR PinName IN-
    PINATTR SpiceOrder 2

    ...and so on...

    We can read it naturally!

    There can be problems of importing some vendor-speciffic and/or encrypted models. BUT no one needs importing a simulation model into PCB design software!

     

    I mean, it is easier to implement natural spice schematics format then inventing new proprietary format...

    And, obviously there is a reason, why RS did not implement it... Hate, war? Conflict with a business model (oh no... don't tell me it is another NI-like good for nothing golden brick)? Or they keep it for $paid product? Really, what do you think?

     

    " if your file contain more information about the schematic construction"

    Those are simulation-speciffic tags. Those tags need not, and should not be imported for the needs of PCB design. Well, those tags may be imported for use in home-brewed simulator or linker... but who needs it for a circuit already checked and double checked in SPICE simulator?

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  • Boss .

    As said an interesting proposal, but I don't think it fits my design process.

    You may end up with a schematic imported, but you then have to import/download the full component to get the package, values for BOM etc.

    What other CAD tools use this route apart from Eagle and how does that assign the full component, not just Sch symbol?

    I really don't follow your "hate war...." stuff, if software doesn't fit your requirements find the one that does. There is no paid for version and no restrictions similar to what other vendors offer.

    My prefered improvement would be the SPICE fully integrated with DSPCB, but again that's my approach....

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  • Andrey Porokhnyuk

    Really, from my point of view, integrating DSPCB with home-brewed SPICE is making another incompatible spice branch with poor support for components.

    There would be a reason implementing all the features of LTspice, TINA and ST software into one engine (since porting models manually is not always possible, because of different models, like temp. dependence, etc.)... But I guess, it is nearly impossible...

    Implementing a universal model database with import and export converters, like Ultralibrarian do for footprints and symbols, along with a link to Ultralibrarian, is a hard, but much better approach.

    And still, the main goal of PCB-CAD is making PCB, not simulating.

    See, making PCB is (1)making links between pins (creating or importing netlist), then (2) drafting paths between footprints. You can reuse many package footprints from compatible components, like it was done in 90s. So the most time is spent on redrawing the circuit, because there are almost no options for netlist import in DSPCB.

    Then, see at the stage (2)  again, we can not export DSPCB layout drafts to specialized routing software, because there are too little save/export options. For instance I want to use TopoR, which is pure routing tool. But it accepts only Eagle format. And there is no way to convert DSPCB to Eagle.

     

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  • Andrey Porokhnyuk

    So, I found the answer myself: http://veecad.com/resource/Eagle_DesignSparkPCB.html

    It is a war, after all. War with business rivals and with common sense.

    The enemy is Farnell. Farnell owns Eagle. So there is a crippled import from Eagle, but no export. Some useful 3rd party tools support Eagle format, but not DSPCB.

    Why are there no netlist import? Guess, there was! At least, there was Orcad net-list import. There is still a function in "keyboard customization", but the feature is dead and the configured hotkey will do nothing. They removed it, probably, in order to remove any reference to Orcad. Guess, same paranoia forbids any SPICE support.

    Well, I finish the board I have already started, and bye-bye RS. I never loved your catalogue after all; Mouser system is organized much better, with less stray and orphan components in search results.

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  • DesignSpark PCB

    DesignSpark Support

    • Dear DesignSpark PCB user – thank you for testing our software!

      Interesting proposition, however up to now we had no request for LTSpice import – so, there is nothing suspicious about it :). Usually people draw schematic in ECAD software first and then simulate blocks of the schematic which require simulation as it was mentioned already in the discussion. That is why we have built-in export to LTspice, TINA, B2 Spice and IsSpice.

      It is easier to find required component models, for ECAD software than in simulation software – especially bigger components like ICs which do not have SPICE models available in public, because they are secret of silicon companies… Additionally ECAD software has usually more functions for graphical formatting than simulation software which rather focus on other aspects than schematic appearance.

      Generally preparing good import or export functionality which will work well in practice it is not an easy task. I experienced this during my years of work as electronics engineer and usually at the end it was better to draw schematic from the beginning than to use cross platform import or export functionality. I just checked import functionality in EAGLE software with new LTspice XVII and it did not work for me as it is only collaborating with LTspice IV according the information on popup window.

      Please supply your ideas for improvement and new functionalities in in the ‘New feature Request’ section and we will analyse what to implement next time based on the biggest popularity and feasibility. We aim to provide a free CAD package that provides the majority of users with the core functionality required for their design work without commercial restrictions.

     

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  • Jayx .

    If it's a war then customers are clearly winning by getting free, unlimited CAD software. By the way, Farnell doesn't own Eagle any more.

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  • Andrey Porokhnyuk

    And what would be the name of that software? I guess, it is not Spark, because it is limited in import and export features.

    Probably, you are talking about KiCAD? I plan moving to KiCAD after this project is finished. I am full of format limitations, problems with changing network names, properties, pin configuration, replacing footprints, and good for nothing footprint system in all aspects... it is a long talk, but though it looked very simple at first, I got really tired fighting with it when started tweaking the board.

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  • Boss .

    @Andrey, you are obviously not using PCB Parts Library, amazing resource. 

    I have been using DSPCB for about 6 years now after frustrations with other CAD systems, not perfect, but is continually improving.

    Last time I looked at the KiCAD forum there seemed to many frustrated users, but perhaps they are at last improving it, have fun.

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  • Andrey Porokhnyuk

    @Boss

    About PCB Parts Library, only components I found there, were some standard BJTs from 70's, and a 555 counter. Comparing to Ultralibrarian - it is nothing.

    Further, I found, that most resistors, diodes and capacitors there have awfully wrong (big, small, nonstandard step) footprint. Without the option to alter the package. And the default package names are unreadable. I have to create EVERY resistor or capacitor from the scratch. That is awfully lot of work. And it is not possible to just substitute, or add the package - you have to change everything in the core; so it is simpler to make a new component. But there again, bugs(limitations) and ambiguities in the footprint editor bringing more pain.

    Just, why didn't they created a library of standard packages with STANDARD names?

     

    The autorouter in the box is completely useless. And there is no option to feed the layout to an external router software. Just exporting to Eagle format would spare me a week. But no. Eagle is a rival - there is no export back.

     

    And you know what? I totally never, by no means, without any doubt - I do not need SPICE module, or export to SPICE from PCB software.

    Because designing a circuit comes first, before designing a PCB. Not counter-wise. So, why would I need it? Checking EMC/interference? Spark does not offer this.

     

    P.S. of course, I use through-hole components for my prototype. It is possible, designing for SMD you wouldn't bump into this problem... But everything is wrong when getting, modifying or creating a new component/footprint. For specific components I use UltraLibrarian. But some footprints are imported with wrong scale, and there is no simple way to fix it. Editor tools set is very simple. And units are often mixed. moving component names along the board is another story...

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