| 摘要 |
PURPOSE:To realize an error checking method of a RAM with extremely high reliability by obtaining a complement of 1 for data on a back-up area and using this complement as the error checking data to check the relevant relation. CONSTITUTION:A complement of 1 is obtained for data of all back-up areas and written into an error check area when a back-up action is started. Then it is decided whether all error checking data are kept or not in the relation of the complement of 1 for the data written into the back area. Based on this deciding result, it is decided at the end of the back-up action whether the backed-up data is normal or not. As a result, a malfunction is produced only in case the same bit as the bit that is not kept normally is not kept normally either for the data on the error check area when the data on the back-up area is not kept normally. Then the probability of malfunctions is extremely reduced. |
