Hitest: A Knowledge-Based Test Generation System

Efforts to develop computer-based automatic test generation for digital circuits have been generally unsuccessful, except in the case of combinational circuitry. Current ATPG methods for sequential circuits often require a considerable amount of computer time and generate unstructured test waveforms of limited value. Experienced human test programmers, on the other hand, appear to have little difficulty in generating high-quality tests for complex sequential circuits when they have a good understanding of how the circuit operates. This article considers the causes of failure in automatic test generation algorithms and describes a new system called Hitest. This system lets the computer use human understanding of circuit operations to generate more effective tests.