i'm new to operating BBB using MATLAB and Embedded Coder Support Package. In Simulink, i need to establish a communication via BBB's UART with a sensor. Though the communication works via MATLAB, I haven't yet succeeded in establishing a communication using the Support Package Library in Simulink. The title of your question confirms what i've suspected: to build a S-Function. Did you use C S-Functions or Level-2 MATLAB S-Functions? Can you send/provide me with the code/example of your S-Function? Hopefully i can help you afterwards. Thanks. Cheers.