Heterogeneous devices are becoming widely diffused in the embedded system domain, mainly because of the opportunities to increase application execution performance and, at the same time, to substantially reduce energy consumption. In such a context, this work faces the role of HW/SW cosimulators/analysis tools for embedded systems based on heterogeneous parallel architectures. In particular, it presents a SystemC-based tool for functional/timing HW/SW co-simulation and analysis within a reference ESL HW/SW co-design flow. The description of the main features of the tool, the main design and integration issues and an illustrative case study represent the core of the paper.