USB input to I2S output does not work for Teensy4.1

[devond76180]

Not sure why, finally just sent it through queues, but would like this to work.


Here is the source code for what does not work. I have patched a since wave to the I2S and can see that it works. I have also done notefrequency on the USB input and know that it works, and since I have used queues and that works it is just the AudioConnection.

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

// GUItool: begin automatically generated code
AudioInputUSB usb1; //xy=226,133
AudioOutputI2S i2s1; //xy=399,126
AudioConnection patchCord1(usb1, 0, i2s1, 0);
AudioConnection patchCord2(usb1, 1, i2s1, 1);
// GUItool: end automatically generated code

void setup() {
// put your setup code here, to run once:
AudioMemory(60);
}

void loop() {
// put your main code here, to run repeatedly:

}

[Saibot]

You need AudioControlSGTL5000 sgtl5000_1; object
I am assuming you are using the audioshield?

[JayShoe]

File>Examples>Audio>Hardware Testing>PassThroughUSB.

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

AudioInputUSB            usb1;           //xy=200,69  (must set Tools > USB Type to Audio)
AudioOutputI2S           i2s1;           //xy=365,94
AudioConnection          patchCord1(usb1, 0, i2s1, 0);
AudioConnection          patchCord2(usb1, 1, i2s1, 1);
AudioControlSGTL5000     sgtl5000_1;     //xy=302,184

void setup() {                
  AudioMemory(12);
  sgtl5000_1.enable();
  sgtl5000_1.volume(0.6);
}

void loop() {
  // read the PC's volume setting
  float vol = usb1.volume();

  // scale to a nice range (not too loud)
  // and adjust the audio shield output volume
  if (vol > 0) {
    // scale 0 = 1.0 range to:
    //  0.3 = almost silent
    //  0.8 = really loud
    vol = 0.3 + vol * 0.5;
  }

  // use the scaled volume setting.  Delete this for fixed volume.
  sgtl5000_1.volume(vol);

  delay(100);
}

// Teensyduino 1.35 & earlier had a problem with USB audio on Macintosh
// computers.  For more info and a workaround:
// https://forum.pjrc.com/threads/34855-Distorted-audio-when-using-USB-input-on-Teensy-3-1?p=110392&viewfull=1#post110392

[devond76180]

Not using any audio shield. This is needed as a generic USB i2s converter in both directions. The I2S input to USB output does not need anything.
Is there really a dependency in the code so that USB input to I2S out only works with the SGTL5000?
A waveform to i2s output works. USB input to notefrequency confirms that data comes in through the USB so that only leaves audioconnection().

[PaulStoffregen]

SGTL5000 is not needed.

I'm running your code (from msg #1) on a Teensy 4.1 and my PC is playing a MP3 file. Here's what my scope sees on pins 8 and 20.



If I press the media pause button on my keyboard, the waveforms turn into this:



Sure looks to me like it's working.