| 摘要 |
<p>PROBLEM TO BE SOLVED: To dispense with an exclusive circuit for determining whether or not a volatile memory to which power is constantly supplied holds a storage content.SOLUTION: An ECU 10 includes a sub-power supply monitor circuit 28 which monitors whether or not a voltage Vconstantly supplied to a sub-microcomputer 16 is not lower than the lowest operation voltage of the sub-microcomputer 16, and can substantially monitor whether or not a voltage Vconstantly supplied to a BuRAM 14B being a volatile memory is not lower than the lowest holding voltage at which a storage content of the BuRAM 14B can be held. When it is determined that an abnormality occurs in the voltage V, the sub-power supply circuit 28 outputs a signal for resetting the sub-microcomputer 16 to the sub-microcomputer 16. When the sub-microcomputer 16 is not recovered, a storage holding plug stored in an incorporated RAM shows a theoretical value indicating that the BuRAM 14B does not hold the storage content. A main microcomputer 14 determines whether or not an error exists in the storage content of the BuRAM 14B on the basis of the storage holding plug of the sub-microcomputer 16.</p> |
