Modeling hierarchical combinational circuits
Jerry R. Burch, David L. Dill, Elizabeth Wolf, Givanni De Micheli · 1993
Hierarchical descriptions of combinational circuits often contain apparent loops [1, 3]. Since it may be difficult to distinguish apparent loops from actual loops, it is useful to construct models of combinational circuits that can handle cyclic dependencies. We show that Boolean relations are inadequate for this purpose, and define a ternary model that solves the problem. We use the model to characterize exact solutions to a broad class of substitution and rectification problems. The theory cleanly handles network transformations that might introduce cyclic dependencies. 1 Introduction The first and most important step in the development of analysis or synthesis methods for any kind of system is the construction of a precisely-defined model. A model should accurately reflect reality (possibly under constraints on the domain of applicability), while providing a "mathematically clean" theory. In this paper we develop a model for the behavior of combinational circuits. Combinational cir...