teensy-audio/examples/Synthesis/Waveforms/Waveforms.ino

// Waveform Example - Create 2 waveforms with adjustable
// frequency and phase
//
// This example is meant to be used with 3 buttons (pin 0,
// 1, 2) and 2 knobs (pins 16/A2, 17/A3), which are present
// on the audio tutorial kit.
//   https://www.pjrc.com/store/audio_tutorial_kit.html
//
// Use an oscilloscope to view the 2 waveforms.
//
// Button0 changes the waveform shape
//
// Knob A2 changes the frequency of both waveforms
//   You should see both waveforms "stretch" as you turn
//
// Knob A3 changes the phase of waveform #1
//   You should see the waveform shift horizontally
//
// This example code is in the public domain.

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

AudioSynthWaveform       waveform1;      //xy=171,84
AudioSynthWaveform       waveform2;      //xy=178,148
AudioOutputI2S           i2s1;           //xy=360,98
AudioOutputAnalogStereo  dacs1;          //xy=372,173
AudioConnection          patchCord1(waveform1, 0, i2s1, 0);
AudioConnection          patchCord2(waveform1, 0, dacs1, 0);
AudioConnection          patchCord3(waveform2, 0, i2s1, 1);
AudioConnection          patchCord4(waveform2, 0, dacs1, 1);
AudioControlSGTL5000     sgtl5000_1;     //xy=239,232

Bounce button0 = Bounce(0, 15);
Bounce button1 = Bounce(1, 15);
Bounce button2 = Bounce(2, 15);

int current_waveform=0;

extern const int16_t myWaveform[256];  // defined in myWaveform.ino

void setup() {
  Serial.begin(9600);
  pinMode(0, INPUT_PULLUP);
  pinMode(1, INPUT_PULLUP);
  pinMode(2, INPUT_PULLUP);

  // Audio connections require memory to work.  For more
  // detailed information, see the MemoryAndCpuUsage example
  AudioMemory(10);

  // Comment these out if not using the audio adaptor board.
  // This may wait forever if the SDA & SCL pins lack
  // pullup resistors
  sgtl5000_1.enable();
  sgtl5000_1.volume(0.8); // caution: very loud - use oscilloscope only!

  // Confirgure both to use "myWaveform" for WAVEFORM_ARBITRARY
  waveform1.arbitraryWaveform(myWaveform, 172.0);
  waveform2.arbitraryWaveform(myWaveform, 172.0);

  // configure both waveforms for 440 Hz and maximum amplitude
  waveform1.frequency(440);
  waveform2.frequency(440);
  waveform1.amplitude(1.0);
  waveform2.amplitude(1.0);

  current_waveform = WAVEFORM_TRIANGLE;
  waveform1.begin(current_waveform);
}

void loop() {
  // Read the buttons and knobs, scale knobs to 0-1.0
  button0.update();
  button1.update();
  button2.update();
  float knob_A2 = (float)analogRead(A2) / 1023.0;
  float knob_A3 = (float)analogRead(A3) / 1023.0;

  AudioNoInterrupts();
  // use Knob A2 to adjust the frequency of both waveforms
  waveform1.frequency(100.0 + knob_A2 * 900.0);
  waveform2.frequency(100.0 + knob_A2 * 900.0);
  // use Knob A3 to adjust the phase of only waveform #1
  waveform1.phase(knob_A3 * 360.0);
  AudioInterrupts();

  // Button 0 changes the waveform type
  if (button0.fallingEdge()) {
    switch (current_waveform) {
      case WAVEFORM_SINE:
        current_waveform = WAVEFORM_SAWTOOTH;
        Serial.println("Sawtooth");
        break;
      case WAVEFORM_SAWTOOTH:
        current_waveform = WAVEFORM_SAWTOOTH_REVERSE;
        Serial.println("Reverse Sawtooth");
        break;
      case WAVEFORM_SAWTOOTH_REVERSE:
        current_waveform = WAVEFORM_SQUARE;
        Serial.println("Square");
        break;
      case WAVEFORM_SQUARE:
        current_waveform = WAVEFORM_TRIANGLE;
        Serial.println("Triangle");
        break;
      case WAVEFORM_TRIANGLE:
        current_waveform = WAVEFORM_TRIANGLE_VARIABLE;
        Serial.println("Variable Triangle");
        break;
      case WAVEFORM_TRIANGLE_VARIABLE:
        current_waveform = WAVEFORM_ARBITRARY;
        Serial.println("Arbitary Waveform");
        break;
      case WAVEFORM_ARBITRARY:
        current_waveform = WAVEFORM_PULSE;
        Serial.println("Pulse");
        break;
      case WAVEFORM_PULSE:
        current_waveform = WAVEFORM_SAMPLE_HOLD;
        Serial.println("Sample & Hold");
        break;
      case WAVEFORM_SAMPLE_HOLD:
        current_waveform = WAVEFORM_SINE;
        Serial.println("Sine");
        break;
    }
    AudioNoInterrupts();
    waveform1.begin(current_waveform);
    waveform2.begin(WAVEFORM_SINE);
    AudioInterrupts();
  }
  
}