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Oscilloscope ? — Parallax Forums

Oscilloscope ?

IbsenIbsen Posts: 68
edited 2006-05-20 19:08 in Propeller 1
Would it be possible to make an Oscilloscope with the Propeller chip ?
Would be cool to use the small monitor for the display...



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Ibsen

" It's nice to be important, but
·· more important to be nice... "

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-05-10 20:15
    I think a couple of the beta group (Paul, Beau) are already going down the this path (low-resolution scope).

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    Jon Williams
    Applications Engineer, Parallax
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-05-11 08:50
    That is why I bought 5 Propeller Chips.

    One is not going to be enough if you use the Propeller to tool up your electronics bench.

    I need at least one to play with, one for an 'O' scope, one for a full RS-232 Video term, one for a game device.
    And one for whatever I didn't know about

    Fortunately I already have a switch box that can share a VGA and keyboard with two devices.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-05-11 13:54
    Ive been working on a logic analyser, Ive got 1 mode done (10MHz sample rate), 2 more to work on (rate specified, pin transition), but life keeps happening (iow free time been eaten up by other things). I posted a screenshot somewhere on this forum, I can look for it later.

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    1+1=10
  • Beau SchwabeBeau Schwabe Posts: 6,545
    edited 2006-05-11 15:00
    Ibsen,
    ·
    ·
    Here is a link to a "Bode Plotter (Frequency vs. Magnitude)" that I put together just
    to see if something like this would be possible.
    ·
    http://forums.parallax.com/showthread.php?p=579380
    ·
    ·
    ·
    The difference is that an Oscilloscope is a representation of "Time vs. Magnitude".· With
    an Oscilloscope you have to make very time critical measurements.
    ·
    While dealing with "Frequency vs. Magnitude" theoretically you could spend all day on a
    specific frequency collecting data.






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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
  • IbsenIbsen Posts: 68
    edited 2006-05-11 15:45
    That is awesome...

    I just wanted a simple oscilloscope for simple bench work and automotive diagnostics...





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    *.*

    Ibsen

    " It's nice to be important, but
    ·· more important to be nice... "
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-05-11 16:07
    Here's that screen shot I mentioned:
    attachment.php?attachmentid=41032

    It could be refashioned in a way to do analog signals, it would take a bit of work though. I have no clue what kind of bandwidth you could expect.

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    1+1=10
  • IbsenIbsen Posts: 68
    edited 2006-05-11 16:58
    Analog would be great !!!

    I'm not looking for super bandwith.



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    *.*

    Ibsen

    " It's nice to be important, but
    ·· more important to be nice... "
  • cgraceycgracey Posts: 14,133
    edited 2006-05-11 17:00
    What bandwidth would be acceptable to you for digital and for analog? I'm curious, because it might be possible to do.
    Ibsen said...



    Analog would be great !!!

    I'm not looking for super bandwith.



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    Chip Gracey
    Parallax, Inc.
  • IbsenIbsen Posts: 68
    edited 2006-05-11 17:02
    What is the resolution of the Storage Scope ???

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    *.*

    Ibsen

    " It's nice to be important, but
    ·· more important to be nice... "
  • IbsenIbsen Posts: 68
    edited 2006-05-11 17:03
    As fast as it will go I guess...

    Even a simple scope would be usefull and cheap copared to buying a real scope...





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    *.*

    Ibsen

    " It's nice to be important, but
    ·· more important to be nice... "
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-05-11 17:13
    depending on the mode, roughly 400 samples (200 for 3rd mode). It is this small because a cog's local memory is filled (in order to achieve a higher bandwidth), hence 3 modes are being worked on to maximize the effectiveness of the small buffer. In mode 1 (completed) a sample is taken every other instruction, or a 10MHz bandwidth (100ns resolution), mode 2 (not completed) samples according to a specified rate, upto 3.33 MHz, mode 3 (not completed) captures every pin transition on a given mask of pins for a specified number of transitions.

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    1+1=10
  • cgraceycgracey Posts: 14,133
    edited 2006-05-11 17:15
    Well, I think 20 MSPS is about all we can practically get digitally and the analog limit is about 2.5MHz at 5 bits resolution. For lower analog sample rates, the analog resolution improves (312KHz samples at 8 bits).

    Would you like the output to go to a TV or to a VGA monitor?
    Ibsen said...



    As fast as it will go I guess...

    Even a simple scope would be usefull and cheap copared to buying a real scope...





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    Chip Gracey
    Parallax, Inc.
  • IbsenIbsen Posts: 68
    edited 2006-05-11 17:20
    WOW, that is cool...

    Output to TV would be fine.

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    *.*

    Ibsen

    " It's nice to be important, but
    ·· more important to be nice... "
  • parskoparsko Posts: 501
    edited 2006-05-12 06:25
    hey chip,

    8 bit res would be awesome. It sounds like you are already doing it!! I would love to have this avail. too. I have a scope, but this might be something more interesting to play with. I would also only be doing mostly automotive stuff. IMHO, if you use a scope like this for computer or other high freq. stuff, you need help, buy a $100 Techtronx 475 like I did.

    -Parsko
  • JamesxJamesx Posts: 132
    edited 2006-05-12 09:54
    For an output, I think VGA would be nice.
  • IbsenIbsen Posts: 68
    edited 2006-05-12 19:16
    How different is the VGA output as far as quality goes ???

    Is there a difference in resolution ???

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    *.*

    Ibsen

    " It's nice to be important, but
    ·· more important to be nice... "
  • El PaisaEl Paisa Posts: 375
    edited 2006-05-15 01:52
    If I remember correctly, IBM original definition of VGA was 640x480 pixels.
  • El PaisaEl Paisa Posts: 375
    edited 2006-05-20 02:47
    Any new develpments in the Oscilloscope program?

    TV mode and/or VGA will be very nice.
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-05-20 18:55
    Still working on the Logic analyser, Ive decided to abandon the old TV interface and adopt the new one released by Chip, in exchange much less memory will be consumed and I can use the waveform charactors to generate the waveforms.

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    1+1=10
  • El PaisaEl Paisa Posts: 375
    edited 2006-05-20 19:08
    Keep the good work and please let us know your progress.
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