Rajit Manohar and Yoram Moses
Asynchrony and concurrency are fundamental notions in the fields of
asynchronous circuits as well as distributed systems. This paper
treats asynchronous circuits as a special class of distributed systems.
We adapt the distributed systems notion of potential causality to
asynchronous circuits, and use it to provide a formal proof of the precise
nature of the isochronic fork timing assumption in quasi delay-insensitive
(QDI) circuits. Our proofs provide a transparent analysis that provides
better intuition regarding the operation of QDI circuits. We build on
our theory to rigorously establish several "folk theorems" about
identifying isochronic forks in QDI circuits.