Scheduling Issues in the Co - Synthesis ofReactive Real - Time Systems 1

Many embedded control applications must respect intricate timing requirements on their interactions with the external environment. These constraints are derived from response time, rate of execution, and low-level signaling requirements. Currently, most of these systems are being designed in an ad hoc manner. Many tools assume the designer has already nalized the scheduling, while most schedulers make simplifying assumptions and often cannot handle general timing constraints. In this paper, we discuss the scheduling issues that must be addressed by co-synthesis tools for embedded systems and outline possible approaches to the problems. Our perspective is based on experience with Chinook, a hardware-software co-synthesis system for reactive real-time systems, currently under development at the University of Washington. Chinook is initially targeting embedded applications without operating system support. From a high-level speci cation and a device library, Chinook synthesizes both interface hardware and a software program to realize the design.