| 摘要 |
PURPOSE:To specify a faulty LSI by retrieving a boundary identification F/F, while executing the shift operation of each LSI for forming a shift path, and comparing the retrieved boundary identification F/F with its expected constant value. CONSTITUTION:Each LSI is provided with boundary identification flip-flop circuits (F/F) (x), (y), respectively, (y) is the F/F connected to shift-in, and (x) is the F/F positioned in the next thereof. In such a state, the F/F on a shift path is shifted by a shift operating instruction 215, and when the values of a pointer register 211 and a shift register 212 coincide with each other by a comparator 21, the values of (x) and (y) are set to a boundary identification register 111. This set value and an expected value register 112 are verified by a comparator 11, and in the case there is abnormality, the chained and propagated values of a stack faulty F/F of the pre-stage are set as x' and y', and noncoincidence is detected by one of them and reported to a firmware. In such a manner, the faulty LSI is specified to one piece. |
