add small sim for audio output

tests/arduino_touchscreen_test/arduino_touchscreen_test.ino

@@ -1,38 +1,164 @@
-void setup() {
-  // put your setup code here, to run once:
-  Serial.begin(9600);
-  Serial.println("\"setup\"");
-  
+uint8_t duty = 50; // start @ 50 % duty
+float freq = 0.44; // start @ 440 hz
+
+void set_duty(uint8_t d) {
+  duty = 100- d;
+  update_freq();
 }
 
+void set_freq(float f) {
+  freq = f;
+  update_freq();
+}
+
+void update_freq() {
+  uint16_t top = freq/0.440*142/2;
+  
+  OCR2A = (top>0xFF)?0xFF:top;
+  OCR2B = top * duty / 100;
+}
+
+void setup_timer() {
+  // setup timer
+  update_freq();
+   
+  TCCR2A= (1<<COM2B1) | (1<<WGM20);
+  TCCR2B= (1<<WGM22) | (1<<CS02); // 64 prescaler ( 5khz == TOP of 50, 1khz = 250 )
+
+  DDRD |= (1<<PD3);
+}
+
+void setup() {
+
+  setup_timer();
+  
+  Serial.begin(9600);
+  Serial.println("setup complete");
+  interrupts();
+}
+
+#include <EEPROM.h>
+
 class Panel {
-  int A,B;
+  int maxVals[2];
+  
+  struct limits {
+    int touchThreas;
+    int minVals[2];
+    float range[2];
+    bool caldone;
+  } limits;
 public:
-  Panel(int one, int two) : A(one), B(two) {
-    pinMode(A, OUTPUT);
-    pinMode(B, OUTPUT);  
+  Panel():maxVals{1,1} {
+    // declare pins as input
+    DDRC &= ~((1<<PC0) | (1<<PC1) | (1<<PC2) | (1<<PC3));
+
+    EEPROM.get(0, limits);
   }
- 
-  int Y() {
-    digitalWrite(A, 1);
-    int result = analogRead(B);
-    digitalWrite(A, 0);
+
+  enum Axis {
+    X = 0,
+    Y
+  };
+  
+  int operator()(Axis axis) {
+    int result = -1;
+    switch(axis) {
+    case X:
+      DDRC  |= (1<<PC0)            | (1<<PC2);
+      PORTC |= (1<<PC0) | (1<<PC1)           ;
+      delay(1);
+      result = analogRead(A1);
+      break;
+    case Y:
+      DDRC  |=            (1<<PC1) | (1<<PC3);
+      PORTC |= (1<<PC0) | (1<<PC1)           ;
+      delay(1);
+      result = analogRead(A2);
+      break;
+    }
+
+    PORTC = 0;
+    DDRC  = 0;
+      
     return result;
   }
-  
-  int X() {
-    digitalWrite(B, 1);
-    int result = analogRead(A);
-    digitalWrite(B, 0);
-    return result;
+
+  float normalized(Axis axis) {
+    if (!limits.caldone)
+      return 0;
+      
+    return ((*this)(axis)- limits.minVals[axis] )/ limits.range[axis];
+  }
+
+  void calibrate() {
+    static int state = 0;
+
+    switch(state++) {
+    case 0:
+      limits.touchThreas = (*this)(X) - 10;
+      break;
+    case 1:
+      limits.minVals[X] = (*this)(X);
+      limits.minVals[Y] = (*this)(Y);
+      break;
+    case 2:
+      maxVals[X] = (*this)(X);
+      maxVals[Y] = (*this)(Y);
+    default:
+      limits.range[X] = maxVals[X] - limits.minVals[X];
+      limits.range[Y] = maxVals[Y] - limits.minVals[Y];
+      limits.caldone = 1;
+      Serial.println("calibration complete");
+      EEPROM.put(0, limits);
+      state = 0;
+    }
+  }
+
+  operator bool() {
+    return ((*this)(X) < limits.touchThreas) || ((*this)(Y) < limits.touchThreas);
   }
   
-} panel(A0,A1);
+} panel;
+
+bool newline = true;
+
+int sigmal = 0;
+int mu = 0;
 
 void loop() {
   // put your main code here, to run repeatedly:
-  Serial.print(panel.X());
-  Serial.print("\t");
-  Serial.println(panel.Y());
-  delay(100);
+
+  if (panel) {
+    float x = panel.normalized(Panel::X), 
+      y = panel.normalized(Panel::Y);
+      
+    int n = x*12;
+    //float freq = powf(1.0595, n - 9) * 0.440;
+    float freq = powf(1.0905, n - 6) * 0.440;
+        
+   // Serial.print(n);
+   // Serial.print("\t");
+   // Serial.println(freq);
+    
+    //analogWrite(11, 255*panel.normalized(Panel::X));
+    
+    
+    set_freq(freq);
+    set_duty(y*100);
+  } else {
+    set_duty(100);
+  }
+
+  while(Serial.available()) {
+    char c = Serial.read();
+    if (newline && c == 'c') {
+      panel.calibrate();
+      newline = false;
+    } else if (!newline && c == '\n') {
+      newline = true;
+    }
+  }
+
+  //delay(100);
 }