740 CHAPTER 14 / ASYNCHRONOUS STATE MACHINE DESIGN AND ANALYSIS
the same thing: they both eliminate critical races, but by entirely different approaches to
state coding. For the STT design the goal is to arrive at an FSM whose transitions take
place simultaneously or nearly so. However, the one-hot design method (for synchronous
or asynchronous machines) forces the FSM to cycle through states having exactly two 1’s,
one from the origin and the other from the destination state. The one-hot approach has the
added advantage that static hazards are automatically covered by the holding conditions.
Thus, cycle paths must be avoided and the sum rule must always hold in the state diagrams
for both STT and one-hot FSMs. Critical races and ORGs are automatically ...