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Thread: Disable volume thumbwheel on Audio Adaptor Rev. C

  1. #1

    Disable volume thumbwheel on Audio Adaptor Rev. D

    Hi, the audio adaptor on top of my T4.1 interferes with the RX of Serial3 (pin15).
    Serial3 reads random numbers with intermittent zeros.
    The audio adaptor is the culprit because if I remove it the RX is fine.
    I noticed on the schematic for the audio adaptor that pin 15 is connected to ground via a 0.1uF capacitor.
    Is this interfering with Serial3?

    When I had a similar problem with pin 6 (a 10k to 3.3V) I cut the connection on the audio adaptor which solved the problem.
    Do I have to cut the connection from pin 15 on the audio adaptor in a similar manner or is there another way of using Serial3 without having to damage the audio adaptor?
    Last edited by johanbilen; 12-07-2020 at 10:23 PM. Reason: Wrong revision

  2. #2
    Senior Member+ Frank B's Avatar
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    Quote Originally Posted by johanbilen View Post
    I noticed on the schematic for the audio adaptor that pin 15 is connected to ground via a 0.1uF capacitor.
    Is this interfering with Serial3?
    yes.
    Quote Originally Posted by johanbilen View Post
    Do I have to cut the connection from pin 15 on the audio adaptor in a similar manner or is there another way of using Serial3 without having to damage the audio adaptor?
    I don't think so.
    You can just remove the capacitor (and - if soldered - the pot).


  3. #3
    Senior Member+ defragster's Avatar
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    For full use the T_4.1 requires the Rev D Audio board.

    Pin #15 still the Vol Pot :: pjrc.com/store/teensy3_audio.html

  4. #4
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    Is there any chance you can avoid that by using one of Serial 6, 7 or 8 instead?

    Pete

  5. #5
    The best solution would as suggested be to desolder the cap or use another Serial, but I ended up cutting pin 15 going into the header on top of the T4.1.
    Thanks
    Johan

  6. #6
    Senior Member+ defragster's Avatar
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    Quote Originally Posted by defragster View Post
    For full use the T_4.1 requires the Rev D Audio board.
    ...
    seeing now the title says Rev C - but text updated to say Rev D audio board

    Not needing the POT connect - all should be good then.
    Last edited by defragster; 12-07-2020 at 11:40 PM.

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