The need for higher level models during system design has resulted in many di erent Electronic System Level (ESL) formalisms that seldom succeeded in the past in the quest for efficient top-down design methodologies. In this paper, we propose a new working toolchain starting from UML speci - cations coupled to an industrial-level system-level synthesis (SLS) tool. In order to isolate a maximum of concepts, we resorted to state-of-the-art model-driven software engineering and strong models-of-computation (MoC). This tooling allows for rapid prototyping of mixed hardware-software systems in line with the high degree of heterogeneity encountered in today embedded platforms.