Hierarchical Models of Synchronous Circuits (Abstract)

We seek a behavioral model of synchronous circuit operation which generalizes Mealy machines in several ways: It should allow the expression of nondeterministic behavior. It should allow parallel composition of machines and hiding of output signals. It should not restrict bidirectional communication between machines. It should deal reasonably with zero-delay cycles, which can be present in unrestricted communication graphs. It should provide a preorder that precisely captures the proper relationship between implementation and specification behaviors. It should allow the computation of the “most general environment” of a circuit.