Add getter function for Timer and LPTimer (#387)

With this API it is possible to retrieve the timer from sketch and
start/stop it using mbed APIs.

Author: giulcioffi

cores/arduino/Arduino.h

@@ -100,6 +100,7 @@ extern analogin_config_t adcCurrentConfig;
 #endif
 
 #include "Serial.h"
+#include "timer.h"
 #if defined(SERIAL_CDC)
 #define Serial _UART_USB_
 #define SerialUSB _UART_USB_

cores/arduino/timer.cpp

@@ -0,0 +1,33 @@
+#include "Arduino.h"
+#include "timer.h"
+#include "mbed.h"
+
+using namespace arduino;
+
+struct _mbed_timer {
+	mbed::Timer* obj;
+};
+
+ArduinoTimer::ArduinoTimer(void* _timer) {
+
+	if (timer != NULL) {
+		delete timer;
+	}
+
+	timer = new mbed_timer;
+	timer->obj = (mbed::Timer*)_timer;
+}
+
+ArduinoTimer::~ArduinoTimer() {
+	if (timer != NULL) {
+		delete timer;
+	}
+}
+
+void ArduinoTimer::start() {
+  timer->obj->start();
+}
+
+void ArduinoTimer::stop() {
+  timer->obj->stop();
+}

cores/arduino/timer.h

@@ -0,0 +1,32 @@
+#include "Arduino.h"
+
+#ifndef __ARDUINO_TIMER_H__
+#define __ARDUINO_TIMER_H__
+
+enum TimerType {
+  TIMER = 0x1,
+  LPTIMER = 0x2
+};
+
+typedef struct _mbed_timer mbed_timer;
+
+namespace arduino {
+
+  class ArduinoTimer {
+    public:
+      ArduinoTimer(void* _timer);
+      ~ArduinoTimer();
+      void start();
+      void stop();
+
+    private:
+      mbed_timer* timer = NULL;
+  };
+
+}
+
+arduino::ArduinoTimer getTimer(TimerType t = TIMER);
+
+#endif //__ARDUINO_TIMER_H__
+
+

cores/arduino/wiring.cpp

@@ -68,6 +68,15 @@ void init()
   lowPowerTimer.start();
 }
 
+ArduinoTimer getTimer(TimerType t)
+{
+  if (t == LPTIMER) {
+    return ArduinoTimer((mbed::Timer*)(&lowPowerTimer));
+  } else {
+    return ArduinoTimer(&timer);
+  }
+}
+
 void yield() {
 #ifndef NO_RTOS
   rtos::ThisThread::yield();