METHOD OF DIAGNOSING A MEMORY FAILURE AND RECOVERING DATA, AND A MEMORY DEVICE USING THIS METHOD

摘要

A memory device using a general-purpose memory not provided with a parity function, which has a memory failure diagnosing function to diagnose written data and, in the event of a memory failure, recover as much data as possible. The method is characterized in that inputted data is parity-calculated, encoded with a predetermined correspondence and stored in a first address of a memory; the results of the parity calculation of the inputted data and the encoded data are stored in a second address of the memory; then, the data stored in the first address is read out and parity-calculated; comparison is made between the results of the parity calculation of the data read out and the results of parity calculation of the inputted data; when they agree, the data read from the first address is outputted as valid data; and when they do not, the encoded data read from the second address is decoded and outputted.