Embedded hard real {time control systems show growing functional complexity as well as increasing demand for short response times and high computing performance. This paper presents a target system architecture suitable for rapid prototyping embedded real {time applications. The tightly coupled heterogeneous multiprocessor system includes state {of {the {art high performance microprocessors as well as Con gurable I/O processors based on eld programmable gate arrays. It is designed to allow better performance guarantees by simplifying the prediction of tight worst case execution times, which are the base for the schedulability analysis of the tasks executed on the microprocessor based nodes. The Con gurable I/O processors are used for both interacting with the embedding system and processing tasks with deadlines too short to be met by software. The automated transformation of the system speci cation and the possibility to connect the prototype to the embedding process allows the validation of the speci cation regarding function as well as timing constraints.