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Thread: Teensy 3.6 TDM mode support for ad1938 codec

  1. #1
    Junior Member
    Join Date
    Apr 2017
    Location
    Germany
    Posts
    1

    Teensy 3.6 TDM mode support for ad1938 codec

    Dear All,

    I am a student working on a project to interface multi channel audio board to Teensy 3.6.

    This multi-channel audio board (ctag face 2/4) based on ad1938 codec and you can find more details about the board in
    https://github.com/ctag-fh-kiel/ctag-face-2-4

    I have connected ad1938 board and Teensy 3.6 board as follows

    AD1938 pins -Teensy 3.6 gpio pins
    Chip select - 7
    MOSI - 11
    MISO -12
    SCK -14
    RESET -17
    ADCBLK -9
    ADCLRCLK -23
    DSDATA1 TX -22
    ASDARA1 RX -13

    I am able to verify the 8 channel i2s in TDM mode with Teensy 3.6 board using"AudioInputTDM" and "AudioOutTDM".
    (4 channels input and 8 channels output).

    I have written a "AudioControlAD1938" class by seeing other codec examples in the teensy audio library.

    I have committed the files in the github fork of Paul's audio library
    https://github.com/yasmeensultana/lib-teensy-audio-fork

    please have a look at control_ad1938.cpp and control_ad1938.h files.

    By default, AD1938 codec is configured as i2s slave 8 channel TDM mode each audio sample 24 bit.

    I will add more functions to support different sampling rates and channels.

    I would like to contribute and improve control_ad1938 class so that other teensy members can use.

    Could you please help me how to create a pull request for these two files.

    please excuse me if there are any mistakes in my coding as I am still student and learning.

    Thanking you in advance

    Yasmeen

    The sketch used for testing
    ---------------------------------
    #include"control_ad1938.h"

    /*
    AD1938 pins Teensy gpio pins
    Chip select - 7
    MOSI - 11
    MISO -12
    SCK -14
    RESET -17

    DAC/ADCBLK -9
    DAC/ADCLRCLK -23

    DSDATA1 TX -22
    ASDARA1 RX -13
    */
    AudioControlAD1938 ad1938codec;

    AudioInputTDM i2s_in;
    AudioOutputTDM i2s_out;

    /*ADC0 to DAC0*/
    AudioConnection pc1(i2s_in, 0, i2s_out, 0);
    AudioConnection pc2(i2s_in, 1, i2s_out, 1);
    AudioConnection pc3(i2s_in, 2, i2s_out, 2);
    AudioConnection pc4(i2s_in, 3, i2s_out, 3);

    /*ADC1 to DAC1*/
    AudioConnection pc5(i2s_in, 4, i2s_out, 4);
    AudioConnection pc6(i2s_in, 5, i2s_out, 5);
    AudioConnection pc7(i2s_in, 6, i2s_out, 6);
    AudioConnection pc8(i2s_in, 7, i2s_out, 7);
    /*ADC0 to DAC2*/
    AudioConnection pc9(i2s_in, 0, i2s_out, 8);
    AudioConnection pc10(i2s_in, 1, i2s_out, 9);
    AudioConnection pc11(i2s_in, 2, i2s_out, 10);
    AudioConnection pc12(i2s_in, 3 , i2s_out, 11);
    /*ADC1 to DAC3*/
    AudioConnection pc13(i2s_in, 4, i2s_out, 12);
    AudioConnection pc14(i2s_in, 5, i2s_out, 13);
    AudioConnection pc15(i2s_in, 6, i2s_out, 14);
    AudioConnection pc16(i2s_in, 7, i2s_out, 15);

    void setup() {
    // put your setup code here, to run once:

    Serial.begin(115200);
    AudioMemory(64);
    AudioInterrupts();

    ad1938codec.init();
    ad1938codec.configI2SSlave();
    ad1938codec.volume(1);
    ad1938codec.enable();
    }

  2. #2
    Junior Member
    Join Date
    Apr 2017
    Posts
    19
    Neat, I have a Rev. A face 2|4 PCB somewhere ...

    Now with this and the CS42448, what are the odds T3.6 will see multichannel USB audio support?

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