Diagnostic device null of error detection correction

摘要

PROBLEM TO BE SOLVED: To attain reliable and sure diagnosis in a short time by successively generating all the patterns of test data and successively generating all the polarity inversion patterns for each pattern without inserting a host device or a diagnostic controller. SOLUTION: At the time of diagnosing, a diagnostic selection signal 33 is set to logic 1, and the initial values of a flip-flop 4 and a counter 3 are set to 0. At this time the output of a decoder 5 is 10,000,000 and a signal inversion circuit 6 inverts the 0-bit of diagnostic data 36 to input to an error detection correcting part (ECC) 22. When an error detection detecting code generating part (ECG) 21 and the ECC part 22 are normal at this time, an ECC error detection signal 37 becomes the logic 1 so that the ECC error detection signal 37 is always observed. When it is not the logic 1, abnormality is found.