Classes of Diagnostic Tests

This paper presents the results of an investigation into the types of tests useful for automatically diagnosing combinational digital devices. The diagnosis is based on a design model that allows hierarchy in both the structure and the data of the device being represented. A more general set of assumptions than is commonly employed allows data values other than boolean values to be diagnosed, and permits faults other than stuck-at faults to be found. The design model, the assumptions, and the tests are represented in SUBTLE, a language based on predicate calculus and specialized for digital systems.