Collective test generation and test set compaction

We present here a scheme of collective test pattern generation (CTPG) in which all tests for each fault in a network are generated as a by-product of the minimization process. This is done efficiently with the use of Binary Decision Diagrams (BDDs), known to provide compact representation and fast algorithms. The test patterns are obtained concurrently with the observability don't care sets through a semi-algebraic method, the extended BDD-based Observability Analysis (BBOA). This kind of collective test generation, potentially, allows good test set compaction since all the possible tests are considered. The compaction is performed by a series of steps consisting of: fault graph construction, maximal independent fault sets extraction and test sets matching. Results on test set size and coverage are presented and discussed.