Hierarchical design methodologies and tools for VLSI chips

Hierarchical design methods are considered to be a means of managing the VLSI design problem. This paper will consider why this problem exists and discuss alternative means that can be used to arrive at a solution. The merits of design methodologies, with emphasis on hierarchical techniques, will be compared with those of automated design approaches. The discussion of hierarchy will lead to the conclusion that the method requires formal abstraction facilities in order to be effective. Hierarchical design methods permit the creation of a new generation of CAD programs that can both give a designer better support and can be much more efficient than the present generation of tools. An example of such a tool, VOILA, will be given.