High-accuracy flush-and-scan software diagnostic

The software technique presented operates over a wide range of defect modes to quickly and accurately diagnose the failing latch in a defective chain without special circuitry or pattern generation. The high-accuracy flush-and-scan software diagnostic technique localizes scan chain defects. Rather than using special tests or circuits, the flush-and-scan technique records the signatures of failures resulting from normal test patterns, and uses software simulations to locate defects. To identify a defective latch, this technique repeatedly simulates different loads (initializations) until the simulation results match those from the tester.