Embedded systems are commonly built upon heterogeneous digital and analog integrated circuits, including sensors and actuators. Model-driven approaches for designing software and hardware are generally limited to the digital parts of systems. In the present paper, we adopt a global view on the extensions made to an integrated modeling and simulation tool, TTool. In this tool, the verification and virtual prototyping of embedded systems is described at different abstraction levels and extended in order to handle analog/mixed-signal systems. An extensive case study spans these levels and illustrates the usefulness of our approach.