Expert system for the functional test program generation of digital electronic circuit boards

CAD (computer-aided design)-generated component and interconnection listings are utilized to recreate a circuit design in the form of an associated network. This is stored within an expert system´s database and enables a powerful search algorithm, under the guidance of testability formulation rules, to explore the circuit. The algorithm interacts with these device models and register-transfer-logic based device operation rules to identify valid test paths through a circuit and thus define functional tests. Once identified, the tests are ordered (using rule-based and heuristic techniques) in terms of increasing test complexity to aid diagnostics. The test paths are passed on to a low-level test timing generator to produce the actual test vectors required to test the board