add example corrected from online example

examples/FreqGenerater/FreqGenerater.pde

@@ -0,0 +1,71 @@
+#include <FrequencyTimer2.h>
+
+void setup() {
+  pinMode(11,OUTPUT);
+
+  Serial.begin(19200);
+  delay(2);
+  Serial.print("Ready");
+
+  FrequencyTimer2::setPeriod(200);
+  FrequencyTimer2::enable();
+}
+
+long burpCount = 0;
+void Burp(void) {
+  burpCount++;
+}
+
+void loop() {
+  static unsigned long v = 0;
+  if ( Serial.available()) {
+    char ch = Serial.read();
+    switch(ch) {
+      case '0'...'9':
+        v = v * 10 + ch - '0';
+        break;
+      case 'p':
+        FrequencyTimer2::setPeriod(v);
+        Serial.print("set ");
+        Serial.print((long)v, DEC);
+        Serial.print(" = ");
+        Serial.print((long)FrequencyTimer2::getPeriod(), DEC);
+        Serial.println();
+        v = 0;
+        break;
+      case 'e':
+        FrequencyTimer2::enable();
+        break;
+      case 'd':
+        FrequencyTimer2::disable();
+        break;
+      case 'o':
+        FrequencyTimer2::setOnOverflow( Burp);
+        break;
+      case 'n':
+        FrequencyTimer2::setOnOverflow(0);
+        break;
+      case 'b':
+        Serial.println(burpCount,DEC);
+        break;
+      case 'x':
+#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega328P__)
+        Serial.print("TCCR2A:");
+        Serial.println(TCCR2A,HEX);        
+        Serial.print("TCCR2B:");
+        Serial.println(TCCR2B,HEX);
+        Serial.print("OCR2A:");
+        Serial.println(OCR2A,HEX);
+#else
+        Serial.print("TCCR2:");
+        Serial.println(TCCR2,HEX);
+        Serial.print("OCR2:");
+        Serial.println(OCR2,HEX);
+#endif
+        Serial.print("TCNT2:");
+        Serial.println(TCNT2,HEX);
+
+        break;
+    }
+  }
+}