Parity-based output compaction for core-based SOCs [logic testing]

SOC test application time is strongly determined by the parallelism attained among core tests. Yet, test bandwidth allocation issues typically impose significant limitations on parallel testing of the cores. In this paper, we propose a response compaction methodology for reducing the required output bandwidth of cores, enabling increased parallelism among core tests and hence reducing overall SOC test time. The proposed methodology is based on judiciously partitioning test responses, with each response fragment being compacted individually. The signature corresponding to the response fragments consists of the parity information which is computed through a cost-effective on-chip space and time compaction mechanism. We show that the proposed technique not only delivers negligible aliasing for any (modeled or unmodeled) fault but that it also provides diagnostic and unknown response value handling capabilities.