Teensy 3.2 not reading in audio correctly

[costelljoe]

I'm trying to use a teensy 3.2 (without audio adapter) to read in audio. I'm using the "PassThroughMono" example which reads in pin A2 and outputs the signal on A14. However, when I connect any input (sine wave of amplitude 1v, centered at 1.5v) the output is flat at 600mV. When I ground pin A2 the output is also flat 600mV. Why does this not see the input correctly?

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

// GUItool: begin automatically generated code
AudioInputAnalog         adc1;           //xy=161,80
AudioOutputAnalog        dac1;           //xy=329,47
AudioOutputPWM           pwm1;           //xy=331,125
AudioConnection          patchCord1(adc1, dac1);
AudioConnection          patchCord2(adc1, pwm1);
// GUItool: end automatically generated code

void setup() {
  // Audio connections require memory to work.  For more
  // detailed information, see the MemoryAndCpuUsage example
  AudioMemory(12);
}

void loop() {
  // Do nothing here.  The Audio flows automatically
}

 

[Theremingenieur]

Why did you not read the documentation in the right sidebar of the audio design tool??? It states clearly „signal range is 0 to 1.2V“. That‘s because of using the internal 1.2V reference for the ADC which gives a more stable and cleaner reference than the 3.3V.

An example circuit to correctly connect and bias an audio signal is also shown there. RTFM