Asynchronous Circuit Design

9

Applications

The memories of a man in his old age are the deeds of a man in his prime.

—Pink Floyd

In theory, there's no difference between theory and practice; in practice, there is.

—Chuck Reid

It's all very well in practice, but it will never work in theory.

—French management saying

An ounce of action is worth a ton of theory.

—Friedrich Engels

A theory must be tempered with reality.

—Jawaharlal Nehru

If the facts don't fit the theory, change the facts.

—Albert Einstein

In this chapter we give a brief history of the application of asynchronous design. An in-depth study is given for one recent successful asynchronous design, Intel's RAPPID instruction-length decoder. Issues in performance analysis and testing of asynchronous designs are also discussed. The chapter concludes with a discussion of the synchronization problem. Although this problem may have prevented the commercial application of RAPPID, it may ultimately be the problem that makes asynchronous design a necessity.

9.1 BRIEF HISTORY OF ASYNCHRONOUS CIRCUIT DESIGN

Since the early days, asynchronous circuits have been used in many interesting applications. In the 1950s and 1960s, asynchronous design was used in many early mainframe computers, including the ILLIAC and ILLIAC II designed at the University of Illinois and the Atlas and MU-5 designed at the University of Manchester. The ILLIAC and ILLIAC II were designed using the speed-independent design techniques developed by Muller and his colleagues. The ILLIAC, ...