Audio Example using 2 DACs on Teensy 3.5 or 3.6

Example using 2 DACs on Teensy 3.5 or 3.6

This example shows how to use the Tonesweep example on the Teensy 3.5 or 3.6 with two DACs (digital to analog converter). The Teensy 3.5 and 3.6 DACs are not amplified.

/*
  Demo of the audio sweep function.
  The user specifies the amplitude,
  start and end frequencies (which can sweep up or down)
  and the length of time of the sweep.

  Modified to eliminate the audio shield, and use the two DACs on the Teensy 3.5 and 3.6.

  Pins:

  A21		Dac0
  A22		Dac1
  Ground:	Ground		Ground
  VIN:		5v		5v  */

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

// GUItool: begin automatically generated code (edited by meissner afterwards).
AudioSynthToneSweep	tonesweep;		//xy=99,198
AudioMixer4		mixer2;			//xy=280,253
AudioMixer4		mixer1;			//xy=280,175
AudioOutputAnalogStereo	dacs;			//xy=452,189

AudioConnection		patchCord1 (tonesweep, 0, mixer1, 0);
AudioConnection		patchCord2 (tonesweep, 0, mixer2, 0);
AudioConnection		patchCord3 (mixer2,    0, dacs,   1);
AudioConnection		patchCord4 (mixer1,    0, dacs,   0);
// GUItool: end automatically generated code

const float	t_ampx	= 0.8;
const int	t_lox	= 10;
const int	t_hix	= 22000;
const float	t_timex	= 10;		// Length of time for the sweep in seconds

// Do a sweep in both directions, enabling or disabling the left/right speakers
void do_sweep (int i)
{
  int do_left  = (i & 1) != 0;
  int do_right = (i & 2) != 0;
  float gain   = (do_left && do_right) ? 0.5f : 1.0f;

  Serial.printf ("Sweep up,   left = %c, right = %c\n",
		 (do_left)  ? 'Y' : 'N',
		 (do_right) ? 'Y' : 'N');

  mixer1.gain (0, do_left  ? gain : 0.0f);
  mixer2.gain (0, do_right ? gain : 0.0f);

  if (!tonesweep.play (t_ampx, t_lox, t_hix, t_timex)) {
    Serial.println ("ToneSweep - play failed");
    while (1)
      ;
  }

  // wait for the sweep to end
  while (tonesweep.isPlaying ())
    ;

  // and now reverse the sweep
  Serial.printf ("Sweep down, left = %c, right = %c\n",
		 (do_left)  ? 'Y' : 'N',
		 (do_right) ? 'Y' : 'N');

  if (!tonesweep.play (t_ampx, t_hix, t_lox, t_timex)) {
    Serial.println("ToneSweep - play failed");
    while (1)
      ;
  }

  // wait for the sweep to end
  while (tonesweep.isPlaying ())
    ;

  Serial.println ("Sweep done");
}

void setup(void)
{
  // Wait for at least 3 seconds for the USB serial connection
  Serial.begin (9600);
  while (!Serial && millis () < 3000)
    ;

  AudioMemory (8);
  Serial.println ("setup done");

  for (int i = 1; i <= 3; i++)
    do_sweep (i);

  Serial.println ("Done");
}

void loop (void)
{
}