This is the first book on embedded systems to offer a unified approach to hardware and software specification and design issues -- and the first to outline a new specify-explore-refine paradigm that is presently being used in industry in an ad-hoc manner, but until now has not been formally described. The book addresses the system design methodology from conceptualization to manufacturing using this new paradigm, and shows how this methodology can result in 10x improvement in productivity. Addresses two of the most significant topics in the design of digital systems -- executable system specification and a methodology for system partitioning and refinement into system-level components. Covers models and architectures; specification languages; a specification example; translation to VHDL; system partitioning; design quality estimation; specification refinement into synthesizable models; and system-design methodology and environment. Contains a complete specification of a model product (telephone answering machine), and demonstrates how to write the specification from an English description. For RISC design methodologists and VHDL methodologists; and CAD software developers.