We address the problems of testing circuits for temporal correctness and synthesizing circuits that can be verified for timing correctness. A circuit is said to be delay-verifiable if its correct timing at the operating speed and also at any slower speed can be guaranteed by applying delay tests. It is shown that some circuits are not delay-verifiable. Furthermore, verifying the timing of a circuit may require tests that can detect the simultaneous presence of more than one path delay fault. This dissertation proposes a general framework for examining delay-verifiability of arbitrary combinational circuits by introducing a special class of faults, called primitive path delay faults. We show that it is necessary and sufficient to test every fault in this class to ensure the temporal correctness of a combinational circuit. A procedure to identify primitive faults is presented. Based on this result, we develop necessary and sufficient conditions for delay-verifiability and provide synthesis procedures for delay-verifiable circuits. The requirement for delay-verifiability is less stringent than existing requirements for delay testability. This provides us with a higher degree of freedom in synthesizing circuits. Experimental data show that circuits obtained by our procedure usually require less area than completely delay testable implementations. Several types of circuits are investigated for their delay-verifiability. It will be shown that many delay untestable circuits are delay-verifiable. The concept of delay-verifiability is a complete solution in the sense that it guarantees full verification for temporal correctness. While delay-testable circuits are always irredundant, delay-verifiable circuits allow the existence of redundancies, which are necessary in some applications. This opens up a new domain of circuits that can be verified for timing correctness.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-8956 |
| Date | 01 January 1994 |
| Creators | Ke, Wuudiann |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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