A Novel Compaction Approach for SBST Test Programs

Abstract: In-field test of processor-based devices is a must when considering safety-critical systems (e.g., in robotics, aerospace, and automotive applications). During in-field testing, different solutions can be adopted, depending on the specific constraints of each scenario. In the last years, Self-Test Libraries (STLs) developed by IP or semiconductor companies became widely adopted. Given the strict constraints of in-field test, the size and time duration of a STL is a crucial parameter. This work introduces a novel approach to compress functional test programs belonging to an STL. The proposed approach is based on analyzing (via logic simulation) the interaction between the micro-architectural operation performed by each instruction and its capacity to propagate fault effects on any observable output, reducing the required fault simulations to only one. The proposed compaction strategy was validated by resorting to a RISC-V processor and several test programs stemming from diverse generation strategies. Results showed that the proposed compaction approach can reduce the length of test programs by up to 93.9% and their duration by up to 95%, with minimal effect on fault coverage.