CHECKING METHOD OF ERROR CORRECTING CIRCUIT AND ERROR CORRECTING CIRCUIT WITH CHECKING FUNCTION

摘要

PROBLEM TO BE SOLVED: To improve the reliability of a system which handles digital data by surely detecting a correction error due to a fault and a metastable state of the error correcting circuit and specifying the occurrence bit of the correction error and to make the operation speed fast by shortening the time needed to evade the metastable state. SOLUTION: A circuit 14 which has the same function as a syndrome generation part 11 generates a syndrome for checking object data of error correction and a circuit 15 having the same function with a syndrome decoding part 12 outputs a correction signal for check by decoding the syndrome for check. Data corrected by a data correction part 13 are compared with data before the correction to detect the bit position corrected by the data correction part 13, and a correction signal for check is compared with the corrected bit position to decide the presence or absence/adequacy of correction data of a fault of the error correcting circuit 10.