A sequential circuit test generation using threshold-value simulation

A simulation-based directed search approach for generating test vectors for combinational circuits has been proposed. In this method, the search for a test vector is guided by a cost function computed by the simulator. Event-driven simulation deals with circuit delays in a very natural manner. Signal controllability information required for the cost function was incorporated in a form of logic model called the threshold-value model. These concepts are now extended to meet the needs of sequential circuit test generation. Such extensions include handling of unknown values, analysis of feedback loops, and analysis of race conditions in the threshold-value model. A threshold-value sequential test generation program, TVSET, is implemented. It automatically initializes the circuit and generates race-free tests for synchronous and asynchronous circuits.<>