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Thread: Teensy 3.5 & Adafruit Max98357 I2S audio amp

  1. #1
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    Teensy 3.5 & Adafruit Max98357 I2S audio amp

    Hi all I am starting a new project and wished to add some basic sound effects to play on events. I have settled on the teensy 3.5 due to the number of available I/O and would like to use the MAX98357 to provide the audio, the inbuilt amp and small size are attractive, however I have a few basic questions.

    Other users have had this chip working with teensy and its audio library, from what I can gather you just need to set I2S as the output with the audio tool and configure the SD card as its source, can you now use the inbuilt SD card of teensy 3.5

    The Adafruit breakout board uses LRC, BCLK & DIN for its I2S data, when you configure the I2S output in the audio designer it gives you the pins for a teensy 3.2. What are the pins on a teensy 3.5 and which pin would need attaching to which on the breakout board, can you select a different output pin or is it fixed.

    Apologies if its already been covered but I haven't managed to figure it out from the supplied information yet.

  2. #2
    Senior Member+ Frank B's Avatar
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    Quote Originally Posted by stathej View Post
    it gives you the pins for a teensy 3.2. What are the pins on a teensy 3.5
    the same
    Quote Originally Posted by stathej View Post
    and which pin would need attaching to which on the breakout board,
    https://www.pjrc.com/store/teensy3_audio.html
    Teensy LRCLK to LRC, TX to DIN, BCLK to BCLK, 3v3 to VIN, and GND to GND
    Click image for larger version. 

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    Quote Originally Posted by stathej View Post
    can you select a different output pin or is it fixed.
    Hm perhaps with patching the audiolib, but i don't recommend it.
    Last edited by Frank B; 01-13-2017 at 06:17 PM.

  3. #3
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    Thanks for the reply, I thought the newer teensy might have changed the location of the I2s outputs with it having more IO pins

  4. #4
    Senior Member PaulStoffregen's Avatar
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    Teensy 3.5 & 3.6 were designed to preserve pinout compatibility, at least on the 28 breadboard-friendly outside pins.

    The only thing that changes for I2S is quad channel input. Even quad channel output is the same, and of course normal 2 channel stereo is the same. But for quad channel input, on Teensy 3.2 you connect the 2nd I2S data signal (for receiving channels 3 & 4) to pin 30 on the bottom side. On Teensy 3.5 & 3.6, that's moved the pin 38.

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