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Thread: Audio Adaptor and T3.5 pin 6

  1. #1

    Audio Adaptor and T3.5 pin 6

    I'm trying to use pin 6 on T3.5 with an audio adaptor. I'm getting 2.5 volt even though I'm using the pin as an input. Is this because it is connected to a pullup-resistor on the Audio Adaptor? I'm not using the MEMS so could I just cut the connection from pin 6 on the Audio Adaptor?

    /Johan

  2. #2
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    Quote Originally Posted by johanbilen View Post
    I'm trying to use pin 6 on T3.5 with an audio adaptor. I'm getting 2.5 volt even though I'm using the pin as an input. Is this because it is connected to a pullup-resistor on the Audio Adaptor? I'm not using the MEMS so could I just cut the connection from pin 6 on the Audio Adaptor?

    /Johan
    There is no MEMS on the audio shield.
    Pin 6 controls the chipselect of the optional memory chip.

    Best is, for this kind of questions, to look at the schematic: https://www.pjrc.com/store/teensy3_audio.html



    As you see ^^^, yes there is a 10k pullup resistor.
    If you don't use the memory chip, you can use the pin for other things. Maybe it's ok to leave the connection? A 10k pullup might be ok - depends on your plans...

  3. #3
    I have a LED connected to the input and the LED is lit even though there's no connection to it.
    /Johan

  4. #4
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    Quote Originally Posted by johanbilen View Post
    I have a LED connected to the input and the LED is lit even though there's no connection to it.
    /Johan
    Why do you connect a LED to a input?
    Anyway, as you said, you can cut the connection.

  5. #5
    Quote Originally Posted by Frank B View Post
    Why do you connect a LED to a input?
    Anyway, as you said, you can cut the connection.
    I'm having a LED light up (GATE IN) when a output (GATE OUT) connected to the input is set high (I'm making a modular synthesizer).
    I have four inputs (Pin 6/17/24/26) and four outputs (Pin 8/16/25/39).
    The three inputs besides pin 6 work fine so when troubleshooting why the LED on pin6 was dimly lit when not connected I noticed that pin 6 was connected to 3.3V via a pullup-resistor on the Audio Adaptor.
    Unfortunately I'm using all other available pins so I guess the only solution is to cut the connection.

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