| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an electronic control unit (ECU) capable of certainly rewriting a control program in each microcomputer regardless of the type of each of a plurality of microcomputers. <P>SOLUTION: This ECU 1 is provided with two microcomputers 5 and 7 each having a flash memory 19, and those microcomputers 5 and 7 communicate with a memory writing device 3 by sharing a communication line 23. Just after the operation is started, when a command signal FCP to be commonly inputted from the memory writing device 3 through a signal line 25 different from the communication line 23 is changed from a low state to a high state, each microcomputer 5 and 7 measures the high level time of the signal FCP, and when the measured value is a time specific to its own device, the microcomputer judges that its own device is the target of data writing. Then, respective microcomputers 5 and 7 exchange their judgement results in the output levels of output ports D1 and D2, and when those judgement results are not contradictory, the microcomputer which judges that its own device is the target of data writing executes processing to update the writing data from the memory writing device 3 and write the updated data in the memory 19. <P>COPYRIGHT: (C)2003,JPO</p> |
