Fix examples isr

examples/SimpleSin/SimpleSin.ino

@@ -9,6 +9,8 @@
 
 #define PWM_PIN 3
 
+#define TIMER2_PHASE_ADVANCE 24
+
 DDS dds;
 
 void setup() {
@@ -26,17 +28,24 @@ void loop() {
   dds.setFrequency(2200);
 }
 
-#ifdef DDS_USE_ONLY_TIMER2
-ISR(TIMER2_OVF_vect) {
-  dds.clockTick();
-}
-#else // Use the ADC timer instead
-ISR(ADC_vect) {
+
+//Uncomment if using dds.startPhaseAccumulator(true);
+/*ISR(TIMER2_OVF_vect) {
   static unsigned char tcnt = 0;
-  TIFR1 = _BV(ICF1); // Clear the timer flag
-  if(++tcnt == 4) {
+  if(++tcnt == TIMER2_PHASE_ADVANCE) {
     tcnt = 0;
+    dds.clockTick();
+  }
+}*/
+
+//Comment if using dds.startPhaseAccumulator(true);
+ISR(ADC_vect) {
+  if(false){
+    static unsigned char tcnt = 0;
+    TIFR1 = _BV(ICF1); // Clear the timer flag
+    if(++tcnt == 4) {
+      tcnt = 0;
+    }
+    dds.clockTick();
   }
-  dds.clockTick();
 }
-#endif