A co-synthesis approach to embedded system design automation

Embedded systems are targeted for specific applications under constraints on relative timing of their actions. For such systems, the use of pre-designed reprogrammable components such as microprocessors provides an effective way to reduce system cost by implementing part of the functionality as a program running on the processor. However, dedicated hardware is often necessary to achieve the requisite timing performance. Analysis of timing constraints is, therefore, key to determination of an efficient hardware-software implementation. In this paper, we present a methodology for embedded system design as a co-synthesis of interacting hardware and software components. We present a decomposition of the co-synthesis problem into sub-problems, that is useful in building a framework for embedded system CAD. In particular, we present operation-level timing constraints and develop the notion of satisfiability of constraints by a given implementation both in the deterministic and probabilistic sense. Constraint satisfiability analysis is then used to define hardware and software portions of functionality. We describe algorithms and techniques used in developing a practical co-synthesis framework, vulcan. Examples are presented to show the utility of our approach.