Circular self-test path for FSMs

Abstract

Circular self test path (CSTP) is an attractive method for automatically transforming sequential circuits generated by automatic synthesis tools into BIST structures. The authors extend this method-making it more suitable for FSMs derived from synthesized control parts-and are integrating it into an industrial design flow supporting testable synthesis. The CSTP approach provides good results in terms of test length and fault coverage in large circuits. It requires substitution of all or some of the flip-flops in the circuit with special cells and their connection to constitute a circular chain. CSTP also has application in industrial environments, and several commercial CAE environments, such as that used by AT&T, now support CSTP as an approach for automatic introduction of BIST in circuits.