Dynamic Fault Collapsing and Diagnostic Test Pattern Generation for Sequential Circuits

Abstract

In this paper, we present results for significantly improving the performance of sequential circuit diagnostic test pattern generation (DATPG). Our improvements are achieved by developing results that permit dynamic, fully functional, collapsing of candidate faults. Fault collapsing permits the organization of faults into disjoint partitions based on the indistinguishability relation. These results are used to develop a diagnostic test pattern generation algorithm that has the same order of complexity as that of detection-oriented test generation (ATPG). Techniques to identify untestable faults, based on exploiting indistinguishability identification, are also presented. Experimental results are presented on the ISCAS 89 benchmark circuits.

On the Use of Functional Test Generation in Diagnostic Test Generation for Synchronous Sequential Circuits

“…The need to consider fault pairs makes the diagnostic test generation process different and more complex than test generation for fault detection. The test generation process can accommodate fault pairs either explicitly, or by modifying the circuit description to inject each one of the faults separately [6]. In the latter case, test generation for fault detection can be carried out on the modified circuits, and a test guarantees that the two faults will be distinguished.…”