Hierarchical Identification of Untestable Faults in Sequential Circuits
Jaan Raik, Raimund Ubar, Anna Krivenko, Margus Kruus · 2007
Similar to sequential test pattern generation, the problem of identifying untestable faults in sequential circuits remains unsolved. Most of the previous works in untestability identification operate at the logic-level and, thus, the methods do not scale. Current paper points out a new class of sequentially untestable faults, called register input logic stuck-on faults. We show that it is possible to identify such faults from the register-transfer level (RTL) description of the circuit. Moreover, we prove by experiments that the considered faults form a large subclass of all the untested faults.