Complete search in test generation for industrial circuits with improved bus-conflict detection

Test Pattern Generation (TPG) for sequential and/or 3-state circuits involves two important aspects which often are handled incorrectly: bus conflict detection and completeness of search in TPG. The correct handling of both aspects strongly depends on the signal model used by TPG. We propose a novel, set-based, signal model using the power-set (i.e., the set of all possible subsets) of the basic values {0, 1, Z}. TPG using this signal model guarantees complete search, provides exact bus-conflict detection, and is more efficient than TPG using the traditional signal models for J-state and sequential circuits. Experimental results demonstrate this by higher fault efficiencies combined with a large reduction of backtracking and computing time for sequential ISCAS'89 and industrial circuits