ABSTRACT
Asynchronous circuits with pulse inputs are said to operate in pulse mode, while those with level inputs are said to operate in fundamental mode. An asynchronous circuit may make a transition to an incorrect stable state as a result of the momentary incorrect signals produced by hazards. Two methods minimize the effect of hazards: using inertial delay lines and using unclocked flip-flops in the feedback path. Type of hazard that causes the asynchronous circuit to malfunction is an essential hazard. The most common asynchronous circuit realization technique to minimize the effects of hazards is to use latches in the feedback paths, since the latch output does not change as a result of a momentary change on its inputs. The chapter examines state assignment procedures through flow tables with three or four rows, though the methods apply to flow tables with any number of rows and columns. Three assignment procedures are popular: shared-row method, multiple-row method, and one-hot method.
