This thesis analyzes the use of Simulink External Mode for the execution, monitoring, and calibration of embedded system models, with a focus on the Universal Measurement and Calibration Protocol (XCP) for host-target interaction during model execution. Adopting a protocol- and architecture-oriented approach, the work examines how External Mode structures the interaction between the host environment and the embedded application. XCP is framed within the ISO/OSI model to highlight the separation of communication layers, considering serial communication and CAN bus as transport mechanisms. The study explores the integration of XCP within automatically generated code, distinguishing between hardware-independent and hardware-dependent layers, and identifying the interfaces that enable adaptation to different hardware targets.