On the automatic generation of SBST test programs for in-field test

Software-based self-test (SBST) techniques are used to test processors against permanent faults introduced by the manufacturing process (often as a complementary approach with respect to DfT) or to perform in-field test in safety-critical applications. A major obstacle to their adoption is the high cost for developing effective test programs, since there is still a lack of suitable EDA algorithms and tools able to automatically generate SBST test programs. An efficient ATPG algorithm can serve as the foundation for the automatic generation of SBST test programs. In this work we first highlight the additional constraints characterizing SBST test programs wrt functional ones, with special emphasis on their usage for infield test; then, we describe an ATPG framework targeting stuck-at faults based on Bounded Model Checking. The framework allows the user to flexibly specify the requirements of SBST test programs in the considered scenario. Finally, we demonstrate how a set of properly chosen requirements can be used to generate test programs matching these constraints. In our experiments we evaluate the framework with the miniMIPS microprocessor. The results show that the proposed method is the first able to automatically generate SBST test programs whose fault efficiency is superior to those produced with state-of-the-art manual approaches.