Add Oscillators tutorial

examples/Tutorial/Part_2_08_Oscillators/Part_2_08_Oscillators.ino

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+// Advanced Microcontroller-based Audio Workshop
+// 
+// Part 2-8: Oscillators
+
+#include <Bounce.h>
+
+Bounce button0 = Bounce(0, 15);
+Bounce button1 = Bounce(1, 15);  // 15 = 15 ms debounce time
+Bounce button2 = Bounce(2, 15);
+
+
+///////////////////////////////////
+// copy the Design Tool code here
+///////////////////////////////////
+
+
+
+
+void setup() {
+  Serial.begin(9600);
+  AudioMemory(20);
+  sgtl5000_1.enable();
+  sgtl5000_1.volume(0.32);
+  
+  pinMode(0, INPUT_PULLUP);
+  pinMode(1, INPUT_PULLUP);
+  pinMode(2, INPUT_PULLUP);
+  mixer1.gain(0, 0.75);
+  mixer1.gain(1, 0.0);
+  mixer1.gain(2, 0.0);
+  mixer1.gain(3, 0.0);
+  mixer2.gain(0, 0.15);
+  mixer2.gain(1, 0.0);
+  mixer2.gain(2, 0.0);
+  mixer2.gain(3, 0.0);
+  waveform1.begin(WAVEFORM_SAWTOOTH);
+  waveform1.amplitude(0.75);
+  waveform1.frequency(50);
+  waveform1.pulseWidth(0.15);
+  sine_fm1.frequency(440);
+  sine_fm1.amplitude(0.75);
+  sine1.frequency(200);
+  sine1.amplitude(0.75);
+  pink1.amplitude(0.75);
+  envelope1.attack(10);
+  envelope1.hold(10);
+  envelope1.decay(25);
+  envelope1.sustain(0.4);
+  envelope1.release(70);
+}
+
+int waveform_type = WAVEFORM_SAWTOOTH;
+int mixer1_setting = 0;
+int mixer2_setting = 0;
+elapsedMillis timeout = 0;
+bool mixer2_envelope = false;
+
+void loop() {
+  button0.update();
+  button1.update();
+  button2.update();
+
+  // Left changes the type of control waveform
+  if (button0.fallingEdge()) {
+    Serial.print("Control waveform: ");
+    if (waveform_type == WAVEFORM_SAWTOOTH) {
+      waveform_type = WAVEFORM_SINE;
+      Serial.println("Sine");
+    } else if (waveform_type == WAVEFORM_SINE) {
+      waveform_type = WAVEFORM_SQUARE;
+      Serial.println("Square");
+    } else if (waveform_type == WAVEFORM_SQUARE) {
+      waveform_type = WAVEFORM_TRIANGLE;
+      Serial.println("Triangle");
+    } else if (waveform_type == WAVEFORM_TRIANGLE) {
+      waveform_type = WAVEFORM_PULSE;
+      Serial.println("Pulse");
+    } else if (waveform_type == WAVEFORM_PULSE) {
+      waveform_type = WAVEFORM_SAWTOOTH;
+      Serial.println("Sawtooth");
+    }
+    waveform1.begin(waveform_type);
+  }
+
+  // middle button switch which source we hear from mixer1
+  if (button1.fallingEdge()) {
+    mixer1_setting = mixer1_setting + 1;
+    if (mixer1_setting == 0) {
+      mixer1.gain(0, 0.75);
+      mixer1.gain(1, 0.0);
+      mixer1.gain(2, 0.0);
+      mixer1.gain(3, 0.0);
+      Serial.println("Mixer1: Control oscillator");
+    } else if (mixer1_setting == 1) {
+      mixer1.gain(0, 0.0);
+      mixer1.gain(1, 0.75);
+      mixer1.gain(2, 0.0);
+      mixer1.gain(3, 0.0);
+      Serial.println("Mixer1: Frequency Modulated Oscillator");
+    } else if (mixer1_setting == 2) {
+      mixer1.gain(0, 0.0);
+      mixer1.gain(1, 0.0);
+      mixer1.gain(2, 0.75);
+      mixer1.gain(3, 0.0);
+      Serial.println("Mixer1: Regular Sine Wave Oscillator");
+    } else if (mixer1_setting == 3) {
+      mixer1.gain(0, 0.0);
+      mixer1.gain(1, 0.0);
+      mixer1.gain(2, 0.0);
+      mixer1.gain(3, 0.75);
+      Serial.println("Mixer1: Pink Noise");
+      mixer1_setting = 0;
+    }
+  }
+
+  // Right button activates the envelope
+  if (button2.fallingEdge()) {
+    mixer2.gain(0, 0.0);
+    mixer2.gain(1, 1.0);
+    mixer2_envelope = true;
+    timeout = 0;
+    envelope1.noteOn();
+  }
+  if (button2.risingEdge()) {
+    envelope1.noteOff();
+    timeout = 0;
+  }
+
+  // after 4 seconds of inactivity, go back to
+  // steady listening intead of the envelope
+  if (mixer2_envelope == true && timeout > 4000) {
+    mixer2.gain(0, 0.15);
+    mixer2.gain(1, 0.0);
+    mixer2_envelope = false;
+  }
+
+  // use the knobs to adjust parameters
+  //float knob1 = (float)analogRead(A1) / 1023.0;
+  float knob2 = (float)analogRead(A2) / 1023.0;
+  float knob3 = (float)analogRead(A3) / 1023.0;
+  waveform1.frequency(360 * knob2 + 0.25);
+  sine_fm1.frequency(knob3 * 1500 + 50);
+  sine1.frequency(knob3 * 1500 + 50);
+}
+
+