A unified framework for race analysis of asynchronous networks

A unified framework is developed for the study of asynchronous circuits of both gate and MOS type. A basic network model consisting of a directed graph and a set of vertex excitation functions is introduced. A race analysis model, using three values (0, 1, and x), is developed for studying state transitions in the network. It is shown that the results obtained using this model are equivalent to those using ternary simulation. It is also proved that the set of state variables can be reduced to a minimum size set of feedback variables, and the analysis still yields both the correct state transitions and output hazard information. Finally, it is shown how the general results above are applicable to both gate and MOS circuits.