| 摘要 |
PURPOSE:To attain the common diagnosis processing which uses a reset signal and at the same time to attain also diagnosis of a logging area, by providing the diagnosis steps for the logging area and other areas and the steps which are saved in the areas excluding the logging area and then restored. CONSTITUTION:A CPU1 writes fixed patterns and parity bits to the areas excluding a logging area 2a and then reads them out to perform a parity check through a parity check circuit 4. Thus the CPU1 diagnoses a work area 2b. At the same time, the CPU1 reads out the contents of the area 2a and writes and saves them to the area 2b. Thus the error detection due to a useless check is prevented in a read mode in case the contents of the area 2a are erased when a power supply is applied. Furthermore the CPU1 diagnoses the area 2a in the same way as the area 2b. Finally the CPU1 reads out the contents saved in the area 2b and writes them to the area 2a to restore the logging contents. |
