Algorithms for the Selection of Applied Tests when a Stored Test Produces Many Applied Tests

Improving the quality of a test set without storing additional tests is important when a higher fault coverage is required but test data storage is limited. Such an improvement can be achieved by using every test in a base test set to apply several different tests. In this paper, we consider the case where a base test set for basic faults is used for detecting more complex faults. Depending on the operators used for producing different applied tests, the number of options available for applied tests can be large. In such cases it is necessary to select a subset of applied tests from all the available ones. We develop algorithms for solving this problem in two scenarios. In the first scenario additional coverage is required for a small subset of faults associated with specific gates. In the second scenario additional coverage is required for the entire circuit. Experimental results are presented for benchmark circuits and logic blocks of the OpenSPARC T1 microprocessor to demonstrate the effectiveness of these algorithms.