In this paper, we extend a model-driven design process for embedded systems to FPGA target platforms. We introduce a VHDL code framework that implements buffered data flow structures and encapsulates hand-written computation kernels. We demonstrate how a toolchain uses the framework to generate system code from behavioral models called activity diagrams. Further, we introduce an interface solution that allows the designer to model and generate hybrid systems of microcontrollers and FPGAs together. Finally, we present a case study for cross-platform system implementation.