Petri nets and digital hardware design

Petri nets are a powerful language for describing processes in digital hardware, and particularly asynchronous or self-timed circuits. Self-timed circuits are designed to operate without the use of a global clock signal. Applications for such circuits are likely to increase during the next decade, due to problems with on-chip event coordination as VLSI technology approaches a density of one hundred million transistors per chip. Designing such circuits without help of formal tools does not seem to be possible. We present an overview of the methods for specification, verification and synthesis of asynchronous circuits with the aid of Petri nets. We present a number of design examples which are used to illustrate the authors' belief that Petri nets could become widely accepted by digital system designers as a design method.