A state encoding for self-checking finite state machines

The design of self-checking FSMs can be achieved by adopting an encoding for the state, for the output or for both. In this paper a state encoding in which the Hamming distance between each state and its possible next states is constant is proposed. The adoption of such an encoding and the application of specific techniques for achieving a complete fault detection property for faults occurring in the next-state logic are presented. Area overhead and fault coverage results on a set of MCNC benchmark FSMs are provided.