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Arduino doesn't create com port

ntewinkel

Hi all,

 

I was leading an Arduino workshop today (using http://www.oomlout.com/a/products/ardx/ image ), and one of the Arduino UNO compatible boards was not creating a com port - it powered up, the usual startup sketch with the blinking light runs, but you cannot see it from the software so getting the next sketch in wasn't working.

 

Switching it out with another UNO fixed it, so we know the software/computer side is all working.

 

My question: is there anything I can do with this board to fix that?

I'm hoping it's something simple and silly. I don't want to spend hours on this, so if the simple answer is "it's bricked" then I'll accept it and move on image

Sending it back would cost more than it's worth.

 

I realize there's a pretty good chance that I can still program it with a roundabout technique, so if all else fails I can always use that route and then make it part of a more permanent project someday.

 

Thanks!

-Nico

Parents Reply
  • 0 in reply to ntewinkel

    well, Nico, it does say:

     

    "To verify you have reset the 8u2 chip: In the Arduino programming environment, check the list of serial ports. The serial port for your board should no longer show up." 

     

    Which appears to be exactly how that board is behaving. 

     

    hmmmm, very interesting,  one might conclude that the 8u2 was accidently reset by shorting its reset pin to ground.

     

    Flip is an USB firmware programmer app from ATMEL.

    For further edification see this tutorial.

     

    I think I will do a 8u2 firmware load    *just*for*fun*  image

     

    Thank for sharing this, Nico.  You helped be learn some new stuff.

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  • 0 in reply to billabott

    It quite likely is a copy, as I bought it on eBay. With opensource hardware there's always that possibility, and the seller never claimed it was a true Arduino, just "compatible". Given that, the boards all look well made, and we didn't have any issues (yet) with all the rest.

     

    I saw that too, about the resetting, and wondered about it. The one that didn't work was the one being handled by the kid that couldn't sit still.

    These boards have the 6 header pins installed (which includes the ones for reset) and it wouldn't take much to short them with, for example, that little motor with the metal body!

     

    I'll try that firmware upload right now too to see how it goes. Thanks for the extra link, I'll check that out too image

     

    Thanks,

    -Nico

  • 0 in reply to billabott

    I tried reloading the firmware for the atmega8u2, which meant (on my Mac) installing macPort and the dfu-programmer.

     

    I followed the procedure to put the chip into DFU mode from the Arduino site: http://arduino.cc/en/Hacking/DFUProgramming8U2

    And also from billabott's link above (mostly the same, except instead of using a resistor they short the 'hwb' for a bit).

     

    But all I get is this message: "dfu-programmer: no device present."

     

    I also noticed that it never shows up in my USB device list (where the other UNO does), so it might very well be that the atmega8u2 chip is not installed properly, or just bad.

     

    So unless someone has a different suggestion, I think I'll give up on this board for now.

     

    Thanks for the help!

     

    Cheers,

    -Nico