WOLFRAM SYSTEM MODELER
This example uses the DigitalOutput component to control the built-in LED on the Arduino board (this pin is controlled using pin 13). It uses a BooleanPulse component from the Modelica Standard Library to produce an On/Off signal that is fed into the DigitalOutput component. This will make the LED blink.
If you would like to add an external LED, you can connect it to pin 9 as shown in the figure below and add one more DigitalOutput component in the model to control the LED.