Multi-clock SOC test schedule based on TWC&S

Both wrapper and TAM are important components in SOC test architecture, and wrapper scan chain optimization and TAM optimization are NP-hard problems. Addressing wrapper scan chain optimization or TAM optimization separately leads to SOC test time sub-optimal. This paper presents a TWC&S (TAM/wrapper co-optimization and scheduling) algorithm for multi-clock SOC after combining the advantages of wrapper scan chain optimization and TAM optimization, and it aims to decrease test time of multi-clock SOC extremely. To demonstrate the validity of the proposed algorithm, experiment is performed on the multi-clock SOC MCDS₂. The results show that there exist inflexion of test time, and the optimal test time is 23.2% when the widths of test bus are 20 vs. the least one. The phenomenon, decreasing degree of test time decreases slowly with test bus widths increase, demonstrates that trade-off will be achieved properly among test time, test area and design complexity.