| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To determine which of the number of operations and the number of failure diagnoses is unwritten into a nonvolatile memory caused by instantaneous interruption of power supply. <P>SOLUTION: When the number of operations and the number of failure diagnoses stored in a back-up RAM is written into the nonvolatile memory 21, a failure diagnoses frequency is calculated by setting the number of operations to a denominator and the number of failure diagnoses to a numerator and the failure diagnoses frequency is firstly written. A calculated failure diagnosis frequency calculated from the number of operations and the number of failure diagnoses read from the nonvolatile memory 21 is compared with a stored failure diagnosis frequency stored in the nonvolatile memory 21. When they are not matched, it is estimated that the firstly written stored failure diagnosis frequency is updated by the writing and at least one of the number of operations and the number of failure diagnoses to be written later is unwritten caused by the instantaneous interruption of the power supply. Since the stored failure diagnosis frequency is correct, it can be determined which of the number of operations and the number of failure diagnoses is unwritten into a nonvolatile memory, or it can be determined that both of them are unwritten. <P>COPYRIGHT: (C)2004,JPO</p> |
