I/O: Add examples

java/libraries/io/examples/Interrupt/Interrupt.pde

@@ -0,0 +1,25 @@
+import processing.io.*;
+color bgcolor = 0;
+
+// RPI.PIN3 refers to the physical pin 3 on the Raspberry Pi's
+// pin header, which is located on the third row, next to a
+// Ground pin
+
+void setup() {
+  GPIO.pinMode(RPI.PIN3, GPIO.INPUT);
+  GPIO.attachInterrupt(RPI.PIN3, this, "pinEvent", GPIO.RISING);
+}
+
+void draw() {
+  background(bgcolor);
+}
+
+// this function will be called whenever pin 3 is brought from LOW to HIGH
+void pinEvent(int pin) {
+  println("Received interrupt");
+  if (bgcolor == 0) {
+    bgcolor = color(255);
+  } else {
+    bgcolor = color(0);
+  }
+}