The C500 microcontroller family provides usually only one on-chip asynchronous serial communication channel (USART). If a second USART is required, an emulation of the missing interface may help to avoid an external hardware solution with additional electronic components. 1 Introduction 3 2 General Operation and Hardware Environment 4 2.1 Supported Features 4 2.2 Required Resources 5 2.3 External Routing 6 2.4 Principles of Emulation 7 2.4.1 USART Write 7 2.4.2 USART READ 8 3 USART Emulation Software Description 9 3.1 Software Structure 9 3.2 Main Program 10 3.3 Emulation Subroutines 12 3.4 Baud Rate Calculation. 12 3.5 Load Measurement 15 3.6 Performance Limitations 16 3.7 Make File 17 3.8 Support of KitCON-513 Evaluation Board 18