| 摘要 |
PROBLEM TO BE SOLVED: To improve the reliability of the re-programmable treatment by protecting the stored content of a non-volatile memory even when the voltage of an on-board battery is dropped in re-programming a flash memory which is mounted on an on-board ECU(Electronic Control Unit) and stores the ECU program. SOLUTION: An on-board ECU4 on which a flash memory 7 is mounted is connected to a memory re-programmable device 1 provided outside a vehicle through an outside harness 2 and an on-board harness 3. A battery voltage minimum value storage part 10 obtains the minimum value of the voltage of an on-board battery when an ignition switch is turned on from the detection result of a battery voltage detection part 5 and an ignition switch condition detection part 6, and stores it in a back-up RAM 11. A re-programming prohibition part 8 reads the minimum value of the battery voltage stored in the back-up RAM 11 before re-programming, and the re-programming of the flash memory 7 is prohibited when the minimum value is smaller than the prescribed threshold which can be re-programmed without any trouble. |
