Add analog functions

Author: facchinm

cores/arduino/wiring_analog.cpp

@@ -0,0 +1,37 @@
+/*
+  wiring_analog.c - analog input and output functions
+  Part of Arduino - http://www.arduino.cc/
+
+  Copyright (c) 2018 Arduino SA
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General
+  Public License along with this library; if not, write to the
+  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+  Boston, MA  02111-1307  USA
+*/
+
+#include "Arduino.h"
+#include "pins_arduino.h"
+
+static int resolution = 10;
+
+void analogWrite(pin_size_t pin, int val)
+{
+  float percent = (float)val/(float)(1 << resolution);
+	mbed::PwmOut((PinName)pin).write(percent);
+}
+
+int analogRead(pin_size_t pin)
+{
+	return mbed::AnalogIn((PinName)pin).read_u16();
+}