First implementation of Tone

Author: facchinm

cores/arduino/Tone.cpp

@@ -0,0 +1,59 @@
+#include "Arduino.h"
+#include "mbed.h"
+
+class Tone {
+    mbed::DigitalOut   *pin;
+    mbed::Timer        timer;
+    mbed::Timeout      timeout;  // calls a callback once when a timeout expires
+    mbed::Ticker       ticker;   // calls a callback repeatedly with a timeout
+    uint32_t           frequency;
+    uint32_t           duration;
+
+public:
+    Tone(PinName _pin, unsigned int frequency, unsigned long duration) : frequency(frequency), duration(duration)  {
+    	pin = new mbed::DigitalOut(_pin);
+    }
+
+    ~Tone() {
+        stop();
+        timeout.detach();
+        delete pin;
+    }
+
+    void start(void) {
+        ticker.attach(mbed::callback(this, &Tone::toggle), 0.5f / float(frequency));
+        start_timeout();
+    }
+
+    void toggle() {
+    	*pin = !*pin;
+    }
+
+    void stop(void) {
+        ticker.detach();
+        pin = 0;
+    }
+
+    void start_timeout(void) {
+        timeout.attach(mbed::callback(this, &Tone::stop), duration/1000.0f);
+    }
+};
+
+Tone* active_tone = NULL;
+
+void tone(uint8_t pin, unsigned int frequency, unsigned long duration) {
+	if (active_tone) {
+		delete active_tone;
+	}
+	Tone* t = new Tone(digitalPinToPinName(pin), frequency, duration);
+	t->start();
+	active_tone = t;
+};
+
+void noTone(uint8_t pin) {
+	if (active_tone) {
+		active_tone->stop();
+		delete active_tone;
+		active_tone = NULL;
+	}
+};