diff --git a/examples/DDS/DDS.ino b/examples/DDS/DDS.ino
index 991ea7f..78ca76c 100644
--- a/examples/DDS/DDS.ino
+++ b/examples/DDS/DDS.ino
@@ -34,7 +34,13 @@ ISR(TIMER2_OVF_vect) {
 }
 #else // Use the ADC timer instead
 ISR(ADC_vect) {
+  static unsigned char tcnt = 0;
   TIFR1 = _BV(ICF1); // Clear the timer flag
+  if(++tcnt == 4) {
+    digitalWrite(2, HIGH);
+    tcnt = 0;
+  }
   dds.clockTick();
+  digitalWrite(2, LOW);
 }
 #endif