Patent ID: 7203581

Claim:
An electronic control unit comprising: a non-volatile memory, which allows electrical updating of data with a limitation in the number of times of data entry, for continuously storing continuous storage object data required to be stored continuously even when electrical power supply is stopped, wherein the continuous storage object data is increased or decreased in its value depending on a specified rule and is changed in its value by a positive number N at a maximum during a single operation period from power on to power off; a control means for executing, on finding that the value of the continuous storage object data is changed in its value by N during the single operation period, a write process to write the continuous storage object data thus changed in its value by N to the non-volatile memory, and for not executing the process to write thereafter the continuous storage object data which has been changed in its value only by N to the non-volatile memory during the same operation period; and a standby RAM supplied with an electric power for a continuous storage of data, wherein the control means includes a periodical storage means for periodically storing the continuous storage object data to the standby RAM during the operation period until at least the data is entered to the non-volatile memory with the write process, and wherein the control means further includes a preliminary write implementation means for writing the continuous storage object data, not yet entered to the non-volatile memory with the write process during a preceding operation period, to the non-volatile memory from the standby RAM when an electric power supply is turned on.