Automated test program reordering for efficient SBST

Software-based Self-test (SBST) is one of the techniques adopted to detect latent faults in safety-critical applications, thus aiming at preventing them from producing failures. When adopted for in-field test, not only the achieved fault coverage, but also the test duration of SBST test programs become critical parameters. Sometimes, these test programs are created following guidelines allowing to guarantee a given Fault Coverage with reduced test duration. In other cases, existing test programs are re-used. Hence, it is important to devise automatic techniques able to modify them in such a way that the fault coverage is kept unchanged (or increased) while the test duration is reduced. This paper presents a possible approach in this direction. Its effectiveness is evaluated on some test programs targeting the openMSP430 processor. Experimental results show that the proposed method is able not only to significantly reduce the test duration (up to 26%), but also to further increase the achieved Fault Coverage, while keeping the required computational time acceptable.