Added example sketch for FM synthesis

software/lib/MMM/examples/Music/_9_FM_synthesis/_9_FM_synthesis.ino

@@ -0,0 +1,39 @@
+// You can set the number of oscillators (1 to 3) and the bit depth of the
+// oscillators (8 or 12 bit). These settings must be defined before the
+// inclusion of the MMM library files. They default to 1 oscallator
+// and 8bit respectively.
+#define FM  // tell the library to use FM synthesis
+#define NUM_OSCILLATORS 2
+#define BIT_DEPTH 12
+
+#include <Music.h>
+
+long time;
+long lastTime = 0;
+long eventTime = 10;
+int cnt = 0;
+int dir = 1;
+
+void setup() {
+
+  // We initialise the sound engine by calling Music.init() which outputs a tone
+  Music.init();
+  Music.setFM2(0);  // this value is already defaulted to 0 in Music.init()
+  Music.setFrequency2(148.3);  // This is the base frequency of the audible oscillator 
+  Music.setFrequency1(487.78);  // This is the modulating frequency
+
+}
+
+void loop() {
+  // This code increases the FM amount from 0 to 127 and back again in intervals defined by "eventTime"
+  time = millis();
+  if(time-lastTime > eventTime) {
+    Music.setFM2(cnt);
+    cnt += dir;
+    if(cnt <= 0 || cnt >= 127) dir *= -1;
+    lastTime = time;
+  }
+  
+
+}
+