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Prop Plug Not Working — Parallax Forums

Prop Plug Not Working

william chanwilliam chan Posts: 1,326
edited 2008-08-19 17:10 in Propeller 1
When I plug in my brand new Prop Plug into my notebook USB port, both LED light up continuously, but no serial ports were found.

So, I pull out the Prop Plug and tried a SX Blitz instead using the same USB cable, COM4 appeared.

I pull out the SX Blitz and plug in the Prop Plug again, now both LEDs do not light up. No serial ports appeared.

I am using the latest FTDI USB drivers.

Is the Prop Plug dead? It is totally new and unused.

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Comments

  • Erik FriesenErik Friesen Posts: 1,071
    edited 2008-08-17 21:17
    Does it do the jingle? If you open up the device manager does it show up at all? It will show up under com ports if enumerating properly. If it is not it will show up as an unknown device.
  • Brian218Brian218 Posts: 92
    edited 2008-08-17 22:29
    It might also be the Propeller chip that is bad.

    I'm not sure exactly how it happened but, Yesterday I had a propeller chip that died. I'm using the 40 pin DIP chip on a breadboard, with the prop plug for programming. I have been using this set-up for the past several months without any problem, until yesterday. Very suddenly, the propeller "could not find...on Com port..." (or something close to that message). After verifying everything was still wired correctly, I swapped chips, and now the new chip is working fine.

    I'm not sure exactly how it happened, but the old chip is now dead. I practice ESD control, and I don't think I did anything that would damage it.

    Good luck
  • Erik FriesenErik Friesen Posts: 1,071
    edited 2008-08-18 02:25
    I have started putting resistors in line to protect the inputs. 470ohms makes no noticeable difference to programming the chip.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2008-08-18 02:52
    The Prop Plug already has series resistors (150 ohms) on its RxD and TxD lines.

    -Phil

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    'Still some PropSTICK Kit bare PCBs left!
  • william chanwilliam chan Posts: 1,326
    edited 2008-08-18 06:33
    Now it seems like when I press down one side of the FTDI chip on the Prop Plug, a com port appears on the PC.
    When I release the pressure on the FTDI chip, the com port stays there.

    Each time I plug in the Prop Plug, I need to put some pressure on one side of the FTDI chip to get a com port to appear.

    Anybody experience this phenomenon before?

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    www.fd.com.my
    www.mercedes.com.my
  • Brian218Brian218 Posts: 92
    edited 2008-08-18 07:37
    william chan said...
    Now it seems like when I press down one side of the FTDI chip on the Prop Plug, a com port appears on the PC.
    When I release the pressure on the FTDI chip, the com port stays there.

    Each time I plug in the Prop Plug, I need to put some pressure on one side of the FTDI chip to get a com port to appear.

    Anybody experience this phenomenon before?
    Not really, but it sounds like it could be a poorly soldered connection on the prop plug/FTDI chip. Normally I'd recommend touching up the connections with a soldering iron, but the pins on the FTDI chip are TINY!

    If you have another propeller chip, swap the chips and see if you get the same results with the 2nd propeller; If you do get the same results, your prop plug is most likely bad (Based on your description, I suspect the prop plug). If the 2nd chip works normally, it's probably the chip itself thats bad
  • BradCBradC Posts: 2,601
    edited 2008-08-18 07:50
    william chan said...

    Each time I plug in the Prop Plug, I need to put some pressure on one side of the FTDI chip to get a com port to appear.

    Anybody experience this phenomenon before?

    Similar. The joints holding the USB connector on my prop plug were all dry. it started out intermittent and eventually just fell off the board..
    Nothing a fine point iron and some lead based solder could not fix though. It'll be a bit harder if a joint under the FTDI chip is dry though.

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    Pull my finger!
  • Paul BakerPaul Baker Posts: 6,351
    edited 2008-08-19 17:10
    William, if you are experiencing intermittant connection problems it's likely that it passed our test because it was making contact at the time, but one or more pins are only in mechanical contact. Since this is a QFN part I wouldn't recommend doing touch up work on it unless you have prior experience with reworking QFN parts. Call Tech Support and we will get it replaced.

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    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
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