| 摘要 |
An electronic control unit has a microprocessor having a nonvolatile memory which is electrically reloadable. Data, with a predetermined loading voltage, is supplied as a condition. The microprocessor controls an object of control during normal operation by executing a control program made up of data stored in the nonvolatile memory. When a predetermined reloading condition has been established, the microprocessor carries out a loading process for loading load data, transmitted thereto from outside the nonvolatile memory, as an update. Along with executing the control program, a monitor signal is generated at predetermined time intervals indicating normal. A system monitoring circuit is also provided for monitoring the monitor signal outputted from the microprocessor. As such, when the monitor signal is not outputted within a predetermined time, a reset signal for resetting the microprocessor is sent to the microprocessor. A blocking circuit is provided for detecting whether the loading voltage is being supplied to the nonvolatile memory and preventing the microprocessor from being reset by the system monitoring circuit when the loading voltage is being supplied.
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