Dynamic diagnosis of sequential circuits based on stuck-at faults

A dynamic diagnosis scheme for synchronous sequential circuits is proposed. In contrast with schemes like fault dictionaries no prior computation and storage of fault symptoms is performed. The technique combines cause-effect and effect-cause strategies. Cause-effect analysis is performed by single stuck at fault simulation followed by a matching algorithm. Effect-cause analysis is performed by an error propagation back-trace starting from the falling outputs. The error propagation back-trace eliminates from consideration faults that could not have caused the failing symptoms. The procedure is exact for defects behaving as single stuck-at faults. Experimental results are provided for the ISCAS89 benchmark circuits