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Favorite free engineering CAD tools

Discussion in 'Electronic Design' started by mook Johnson, Aug 28, 2006.

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  1. mook Johnson

    mook Johnson Guest

    What are your favorite engineering cad tools avaialble free on the web.

    Here are mine:

    1) Circuit simultors
    Orcad Student version -50 node limit

    2) FPGA development tools

    3) DSP tools (FIR,IIR,FFT, etc)

    4) PCB CAD packages

    5) magnetics simulation

    6) assembler
    Microchip for pic projects.

  2. Joel Kolstad

    Joel Kolstad Guest

    LTSpice, no limit whatsoever.
    Xilinx WebPack... pretty much covers any of the devices someone doing
    development on a shoestring budget is going to be able to afford. :)
    Altera's freebies are decent too.
    Good choice.

    I left out the items where I don't have a favorite or have little experience.
  3. Joerg

    Joerg Guest

    Hello Mook,
    Like Joel I prefer LTSpice. The wiewing window for sim results is IMHO a
    bit hokey (x-axis keeps popping back to unusable ranges) but other than
    that a fine program.

    Only FIR filters. I like some old DOS programs better but my favorite
    one from Mildenberger talks German so I guess it wouldn't help you. I
    wish the more fancy ones would go into wave digital filters and stuff.
    But they don't.

    If you design a lot of analog filters of the LC kind try Aade's Filter
    Design. Not very comfy but fast.

    Very good. Licenses for "real" versions are much more reasonable priced
    than other tools. This is one case where the willingness to offer a
    useful free version has paid off. I bought it shortly after kicking the
    tires on the free version.

    Never tried it but my experience is that this stuff really needs to be
    tested in the lab, and very thoroughly.

    Try the EZ430 kit from TI. Not free but only $20 for USB programmer,
    target board and C- plus assembler tool. Can't beat that, I believe. The
    IAR basic Kickstart tool is free BTW in case you decide to set up your
    own hardware. But you couldn't possibly do that for under $20.

    AppCAD from HP. Saves you from whipping out the slide rule, the
    calculator and the formula books too often.

    Then GCPreview for checking Gerbers. No "see-through" plane patterns but
    heck, there is a free version so I won't complain.
  4. Checkout Reg Edward's site, has a lot of RFfy programs,

  5. Nico Coesel

    Nico Coesel Guest

    Is there any software that allows to get started with WDF filters?
    German language is not a problem.
  6. Joel Kolstad

    Joel Kolstad Guest

    OK, if we're going to branch out into other free software tools:

    Another good free Gerber previewer is Viewmate by Pentalogix.
    Viewing AutoCAD/SolidWorks files: eDrawings
    More LC filter design: Elsie (AADE is quite good too -- the two are just a
    little different)
    Transmission line design: TxLine from AWR
    Text editor: EditPad Lite

  7. With the focus on the sim results, click Plot Settings -> Save plot
    settings. When you get a new plot with axes you don't like, click Plot
    settings -> Reload plot settings. Your preferred axes will be restored.
    You can use short-cut keys, of course.
    I just wish there was a comprehensive manual. But it would be a mammoth
    task to compile and couldn't be done without the full co-operation of
    the author. Many of the most valuable features are undocumented; you
    have to learn them from others.
  8. John Larkin

    John Larkin Guest

    Xilinx WebPak



  9. Joerg

    Joerg Guest

    Hello Nico,
    Yes, the program written by Prof.Mildenberger's group at the
    Fachhochschule Wiesbaden in the late 80's. Unfortunately now that he's
    retired they dumped his web site. Since the web archive butchered the
    file one of the fellows in the German NG repaired the zip file:
    I have the older licensed version but later it became free.

    There is also a large set of routines from TU Delft but they did the
    usual, it's all Matlab and very incompatible with anything else. Even
    within Matlab versions. So I could not use that. Had they chosen to
    create a "real" stand alone program from it the TU in Delft could have
    gained lots of prestige instead of seeing it all go towards that dusty
    shelf in the basement.
  10. Joerg

    Joerg Guest

    Hello John,

    On the last one it croaked even before that. Right click in the plot
    window -> manual limits -> entered new right limit. Zilch. Nada. Just
    sits on the (useless) default.

    Yes, but luckily there are some very helpful (and English-speaking)
    folks like Helmut Sennewald.
  11. Joel Kolstad

    Joel Kolstad Guest

    The Mathworks has had a compiler for Matlab (that can create standalone
    applications) for years now, although apparently it's one of those things
    where often universities have a site license for Matlab itself (and various
    toolboxes) but often don't end up licensing the compiler.

  12. Mark Fortune

    Mark Fortune Guest

    I got recommended eagle by someone, tried it, loved it. works on windows
    and linux too, so I can use it at home and at the girlfriends place.

  13. Joerg

    Joerg Guest

    Hello Joel,
    Well, universities often just don't finish stuff. If they do then they
    don't maintain it long term. Even the school where the father of wave
    digital filters (Professor Fettweis) taught is a sad example. The center
    of competence around him seems to have disintegrated. The result? About
    90% of my peers don't have a clue what a wave digital filter is.

    This is one of the reasons why I decided to take the plunge and not
    pursue a Ph.D. I firmly believe that one must have a strong sense of
    long-term commitment and not hop from one interesting project (or job)
    to another just because something else looked more glamorous.
  14. Joerg

    Joerg Guest

    Hello Mark,
    It is a great SW and much lower in cost than OrCAD. Plus they don't
    force-upgrade people by coming out with new versions all the time which
    is what finally convinced me to switch from OrCAD to Eagle. Also, they
    actually communicate with their customers a lot (what a concept...).

    But using Eagle at the girlfriend's place is usually frowned upon (by
    the girlfriend).
  15. Joel Kolstad

    Joel Kolstad Guest

    Hi Joerg,

    There's no funding in making "polished products," as far as I can tell... you
    get your software/design process/whatever to the point where you can publish a
    paper or two -- knowing that it has plenty of quirks/bugs/etc., but all ones
    that you know of so that you can work around -- and then it's on to the next
    project. :-(
    Well... ok, but if commercial entities were had such a strong sense of
    long-term commitment, don't you think that software would generally be
    somewhat less buggy than it is today? Most companies seem to spend more
    effort introducing "glamorous new features" than they do fixing their bugs...

  16. Mark Fortune

    Mark Fortune Guest

    It was either that, or haul my workshop round there.
  17. Yes, see my last sentence. It works, but it's not a terribly good
    substitute for a manual.
  18. Joerg

    Joerg Guest

    Hello Joel,

    Sadly, that's their way of thinking and IMHO it's wrong. If they would
    collaborate and form competence centers they would gain so much more
    status and fame with industry. This in turn would lead to more lucrative
    research contracts and that would bring urgently needed money to
    universities. But the way it is now, during most industrial projects we
    don't even consider involving a university. That could be different. But
    only after we see them follow through with their own things.

    A great example of doing it right is the Werkzeugmaschinenlabor (WZL) at
    RWTH Aachen University (my alma mater). They design and maintain a well
    rounded set of CAD tools. Consequently, in my days they were quite flush
    with research funds from companies who needed help in mechanical
    engineering. I fondly remember the keggers they regularly threw on their
    front lawn. Money didn't seem to be an issue there.

    I've tried to talk to some about it but it is like kicking an oak tree
    so I stopped.
    It exists. Look at Cadsoft Eagle. I have yet to have it do a hard crash
    and I haven't discovered any tough bug. The only weirdness is that you
    sometimes have to unselect and select the printer. Kind of like the
    double-clutching on large trucks. Oh well, if that's all I can live with it.

    After a while it becomes obvious which companies can achieve quality and
    which ones cannot. Just like with cars where there are certain brands or
    models I would never buy. This can vary even within companies. For
    example, while IMHO much SW from MS is very sub-par there is other SW
    such as MS-Works which is and always has been of a solid quality. So I
    use that for my book-keeping.
  19. Joerg

    Joerg Guest

    Hello John,

    True. In the case of (otherwise often excellent) university software
    it's worse. After a few years the folks that were involved have left and
    now there is nobody who has much of a clue. Only a handful of people
    knew how to fly it. It's like building a complicated piece of test
    equipment and not labeling the front panel because you know what all the
    buttons do.
  20. Mr. J D

    Mr. J D Guest

    ProgeCAD, Circuit Maker.
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