PURPOSE: To enable a flexible self inspection to match inspection purposes, by freely selecting the number of test patterns with a selection mechanism.
CONSTITUTION: The number 100 of test patterns read out from an ROM 4 and the corresponding expectation code 200 are selected in sets with selectors 5 and 6 separately according to select signals 20. As the number 100 selected reaches counts of clocks with a counter 9 to be applied to a pseudo random number generator 2 which supplies random number patterns to a circuit 1 to be inspected, a comparator 7 turns ON a stop signal. On the other hand, the contents of a code analyzer 3 responding to the output of the circuit 1 are compared with the code 200 selected with the selector 6 and a comparator 8 outputs an ON or OFF signal according to the coincidence and non-coincidence thereof. These signals are inverted and fed to an AND gate 300 to be opened by the stop signal and an error signal is outputted in case of a trouble. Thus, the number of test patterns can be selected freely thereby enabling a flexible self inspection to match with inspection purposes such as processing condition of production.
HIYAMA TORU
MIYAMOTO SHUNSUKE
