Asynchronous Circuit Design A Tutorial

Asynchronous circuits have characteristics that differ significantly from those of synchronous circuits and, as will be clear from some of the later chapters in this book, it is possible exploit these characteristics to design circuits with very interesting performance parameters in terms of their power, performance, electromagnetic emissions (EMI), etc. Asynchronous design is not yet a well-established and widely-used design methodology. There are textbooks that provide comprehensive coverage of the underlying theories, but the field has not yet matured to a point where there is an established currriculum and university tradition for teaching courses on asynchronous circuit design to electrical engineering and computer engineering students. As this author sees the situation there is a gap between understanding the fundamentals and being able to design useful circuits of some complexity. The aim of Part I of this book is to provide a tutorial on asynchronous circuit design that fills this gap. More specifically the aims are: (i) to introduce readers with background in synchronous digital circuit design to the fundamentals of asynchronous circuit design such that they are able to read and understand the literature, and (ii) to provide readers with an understanding of the “nature” of asynchronous circuits such that they are to design non-trivial circuits with interesting performance parameters. The material is based on experience from the design of several asynchronous chips, and it has evolved over the last decade from tutorials given at a number of European conferences and from a number of special topics courses taught at the Technical University of Denmark and elsewhere. In May 1999 I gave a one-week intensive course at Delft University of Technology and it was when preparing for this course I felt that the material was shaping up, and I set out to write the following text. Most of the material has recently been used and debugged in a course at the Technical University of Denmark in the spring 2001. Supplemented by a few journal articles and a small design project, the text may be used for a one semester course on asynchronous design.