Understanding Hierarchical Design

Author: Rowson, James Allely

Year: 1980

Degree: Dissertation (Ph.D.)

Advisor: Mead, Carver

Committee Member: Unknown, Unknown

Option: Computer Science

DOI: 10.7907/Z9BP00R2

Abstract

With the exponential improvement in integrated circuit technology comes the problem of how to design systems containing millions of devices. This thesis presents a new look at hierarchical design based on the Caltech structured design methodology.

The hierarchy is separated into two parts: leaf cells, containing no instances of other cells, and composition cells, containing only instances of other cells. A leaf cell can be implemented in many different representations. A representation consists of a set of leaf cells and a composition rule that builds correct higher level cells.

The separated hierarchy is suitable for mathematical analysis by the use of Curry's theory of combinators. In this form, a hierarchy is represented by a mathematical operator that produces a digital system from the leaf cells. The question of hierarchical equivalence is examined.

Three sample composition rules, or algorithms, are presented as examples. The SLAP system provides a geometry composition rule that produces the mask description of a system given the geometries of the leaf cells. In analogy to TYPEing in a programming language, two representations that enforce a certain design style are discussed. The first TYPE system guarantees signal integrity. The second TYPE system guarantees mutual exclusion between the sources on a bus.

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