added Basic_IO example

Author: lathoub

examples/Basic_IO/Basic_IO.ino

@@ -0,0 +1,25 @@
+#include <USB-MIDI.h>
+
+// Simple tutorial on how to receive and send MIDI messages.
+// Here, when receiving any message on channel 4, the Arduino
+// will blink a led and play back a note for 1 second.
+
+USBMIDI_CREATE_DEFAULT_INSTANCE();
+
+void setup()
+{
+    pinMode(LED_BUILTIN, OUTPUT);
+    MIDI.begin(4);                      // Launch MIDI and listen to channel 4
+}
+
+void loop()
+{
+    if (MIDI.read())                    // If we have received a message
+    {
+        digitalWrite(LED_BUILTIN, HIGH);
+        MIDI.sendNoteOn(42, 127, 1);    // Send a Note (pitch 42, velo 127 on channel 1)
+        delay(1000);		            // Wait for a second
+        MIDI.sendNoteOff(42, 0, 1);     // Stop the note
+        digitalWrite(LED_BUILTIN, LOW);
+    }
+}