| 摘要 |
PURPOSE:To hold values of the latch group of a partial circuit to be diagnosed and take a diagnosis without the intervention of an operator by adding a partial circuit which cuts off a signal to the latch group and substituting this latch group with an equivalent circuit. CONSTITUTION:A partial circuit 29 consisting of an AND gate 25 which inhibits the input of a signal to an input latch 22 of a partial circuit 28 to be diagnosed, and a latch 26 is added to the partial circuit 28 to be diagnosed, and the partial circuits 28 and 29 are regarded as a test pattern generation uint. Then, the input latch 22 is substituted with the equivalent circuit which outputs an indefinite value ''X'' when the level of a timing signal supply line 27 is ''1''. If a single regenerative fault occurs on an input signal line 30 of an OR gate 33, that is detected from the propagation through the OR gate 33, the transmission of a timing signal T0 from an output latch 34, and the scanning-out operation of the output latch 34, so such a test pattern that a timing input signal line 37 of an equivalent circuit 32 is set to ''0'' is generated to attain the detection. |
