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Building optimal test sets for checking complex digital devices

Building optimal test sets for checking complex digital devices

Organization of control of digital devices based on the assessment of the reliability of their functioning

The performance reliability indicators characterize the operability of the “test object – test tool” system and significantly depend on the performance reliability parameters of the testing equipment. Consequently, they can serve as criteria for selecting the necessary tools at the design stage of digital devices and assessing their effectiveness. The paper proposes quantitative criteria for assessing the effectiveness of the hardware testing method based on the assumption that a digital device performs a certain generalizing function, the values of which depend on a set of quantities reflecting individual operating modes of the device, and can be classified as correct only if there are no errors in the operating device. To quantitatively assess the performance reliability of the equipment, it is proposed to use the probability value that the digital device as a whole will function error-free provided that there is no detectable fault. The calculated evaluation value allows you to select the best of several possible test circuit options or synthesize a new one. Cases of organizing test procedures based on various principles and their combinations are considered. An optimization problem of placing test circuits in a tested device is formulated and a technique for solving it under certain restrictions is proposed. A distinctive feature of the proposed approach is the elimination of the need to use the values of conditional probabilities of detected faults, on the use of which known methods are built, although their practical receipt is very labor-intensive. The operation of the method of rational placement of control circuits is illustrated by the example of a control signal block. Read more...