A hierarchical test pattern generation system based on high-level primitives

The authors present an extension of the automatic test pattern generation system SOCRATES to a hierarchical test pattern generation system for combinational and scan-based circuits. The proposed system is based on predefined high-level primitives, e.g., multiplexers and adders. The exploitation of high-level primitives leads to significant improvements in implication, unique sensitization, and multiple backtrace, all of which play a key role in the efficiency of any automatic test pattern generation (ATG) system. In order to perform deterministic ATG and fault simulation for internal faults of high-level primitives, the high-level primitives are dynamically expanded to their gate-level realization. A number of experimental results, achieved on circuits with several tens of thousands of primitives, demonstrate the efficiency of the proposed approach in terms of CPU time, fault coverage, and memory requirements