Vespira created a project  forking a previous one made with Arduino Uno. In this case all audio is generated on the Arduino Micro:

If you look closely, you will see that I added a yellow wire going from the TXLED to the empty hole that was drilled over by the reset button. I added a single pin though this hole and epoxied the plastic in place to give myself another bread-boardable pin that has access to the PD5 signal which was not broken out. Simple mod really.