Sequential test generation based on circuit pseudo-transformation

The test generation problem for a sequential circuit capable of generating tests with combinational test generation complexity can be reduced to that for the combinational circuit formed by replacing each FF in the sequential circuit by a wire. In this paper, we consider an application of this approach to general sequential circuits. We propose a test generation method using circuit pseudo-transformation technique: given a sequential circuit, we extract a subcircuit with balanced structure which is capable of generating tests with combinational test generation complexity, replace each FF in the subcircuit by wire, generate test sequences for the transformed sequential circuit, and finally obtain test sequences for the original sequential circuit. We also estimate the effectiveness of the proposed method by experiment with ISCAS'89 benchmark circuits.