Asynchronous Circuit Design: Motivation, Background, & Methods

Abstract

The purpose of this book is to present a current view of the state of the art for the field of asynchronous circuit design and analysis which was the topic of a workshop in Banff in the fall of 1993. Asynchronous circuits have been studied in one form or another since the early 1950’s [64] when the focus was primarily on mechanical relay circuits and when the differences between the asynchronous and clocked circuit design styles were somewhat indistinct. A number of theoretical issues were studied in detail by Muller and Bartky as early as 1956 [92]. Since then, the field of asynchronous circuits has gone through a number of high-interest cycles. In the last 5 years there has been an unprecedented level of interest in both academic and industrial settings [56]. This historical trend continues today with the majority of the current research effort focused more on theory than on practice. Nonetheless, the advance of practical asynchronous circuit design techniques also has an unusual level of interest. The work presented at the Banff workshop was concerned more with practice than theory and provided a reasonable coverage of the current approaches to asynchronous circuit design. Similarly this chapter will primarily focus on practical design issues. Prior to introducing the four chapters which follow, we present an introduction to the basic concepts and motivations behind asynchronous circuit design. This will hopefully enable those not already familiar with asynchronous circuit design to better understand the subsequent chapters.