Model-based design (MBD) involves designing a model of a control system, simulating and debugging it with dedicated tools, and finally generating automatically code corresponding to this model. In the domain of embedded systems, it offers the huge advantage of avoiding the time-consuming and error-prone final coding phase. The main issue raised by MBD is the faithfulness of the generated code with respect to the initial model, the latter being defined by the simulation semantics. To bridge the gap between the high-level model and the low-level implementation, we use the synchronous programming language Lustre as an intermediate formal model. Concretely, starting from a high-level model specified in the de-facto standard Simulink, we first generate Lustre code along with some structured "glue code", and then we generate embedded real-time code for the Xenomai RTOS. Thanks to Lustre's clean mathematical semantics, we are able to guarantee the faithfulness of the generated multi-tasked real-time code.