Add analogWrite example

Author: pennam

examples/analogWrite/analogWrite.ino

@@ -0,0 +1,38 @@
+/*
+  Portenta Breakout - analogWrite
+
+  The sketch shows how to use analogWrite API of the Portenta Breakout.
+
+  The circuit:
+   - Portenta H7
+   - Portenta Breakout
+
+  This example code is in the public domain.
+*/
+#include "Arduino_PortentaBreakout.h"
+
+void setup() {
+  Serial.begin(9600);
+  while (!Serial);
+  
+  //Default write resolution is 8bits
+  Breakout.analogWriteResolution(8);
+
+  //PWM0 and PWM3 are using HRTIM peripheral and minimum frequency is 760Hz
+  Breakout.analogWrite(PWM0, 25);
+  Breakout.analogWrite(PWM1, 50);
+  Breakout.analogWrite(PWM2, 75);
+  Breakout.analogWrite(PWM3, 100);
+  // PWM4 and PWM8 are sharing the same timer channel therefore is not possible 
+  // to use both outputs at the same time
+  Breakout.analogWrite(PWM4, 125);
+  Breakout.analogWrite(PWM5, 150);
+  Breakout.analogWrite(PWM6, 175);
+  Breakout.analogWrite(PWM7, 200);
+  //Breakout.analogWrite(PWM8, 225);
+  Breakout.analogWrite(PWM9, 250);
+}
+
+void loop() {
+    delay(100);
+}