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Thread: Teensy 3.xx and h/w (DIN) MIDI

  1. #1

    Teensy 3.xx and h/w (DIN) MIDI

    Hi,

    My understanding is that the 3.xx series is fundamentally a 3v system w/ 5v 'tolerance' on the digital pins. I'm currently using a Mega 2560 for it's 4 UARTS, but it's running out of steam for my app.

    Given the variety of MIDI h/w deviations out there, can the the Teensy 3.2 safely be used to connect to the outside MIDI world through an optocoupler on the inputs and a 220v resistor, etc., on the outputs? I guess what I need to know is whether the Tx/Rx lines are '5v tolerant'.

    Thanks much.

  2. #2
    Senior Member adrian's Avatar
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    Use this scematic modified as per the text for 3.3v teensy 3.x . Works for me ... note that because you are using an opto coupler, you don't need to stress about the rx input pin ... power the optocoupler with 3.3v!
    Last edited by adrian; 04-05-2016 at 03:15 AM. Reason: rx not tx! dammit

  3. #3
    Thank you, Adrian. As many times as I've referred to that schematic when using my Teensy 2.0's, I never caught the text about the 3.xx resistors. Cripes, I'm getting old...

  4. #4
    Senior Member adrian's Avatar
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  5. #5
    Not sure if it's any help but I made a PCB for this last year (it was my first PCB, and it should certainly be re routed or redone in kicad).
    It's a total copy of the schematic pjrc provides.

    This is the thread https://forum.pjrc.com/threads/27977-Midi-PCB

    https://github.com/jjrh/midi_shield

  6. #6
    Senior Member adrian's Avatar
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    Cool ... thanks .... I use perf board... note the lack of decoupling caps OMG!

  7. #7
    For lot of people familiar with Arduino boards, think of Teensy 2.0 as good Uno, Teensy++ 2.0 as a better Mega2560 and Teensy 3.0 as a Due done right .It predates the Due

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