Elimination of Dynamic Hazards by Factoring

We propose a novel method to eliminate dynamic hazards in asynchronous circuits synthesized from the signal transition graph (STG) specifications. We first review a relationship between syntactic constraints such as liveness and complete state coding at the STG level and the hazard properties at the gate level. Using this relationship, we identify the cause of dynamic hazards and remove them by an iterative factoring method. Each factoring entails augmenting the given STG with an internal signal. This method is applicable to both combinational and sequential circuits, and results in hazard-free multi-level implementations from STG specifications.