| 摘要 |
<p>PROBLEM TO BE SOLVED: To simplify interface circuits on a transmission side and a reception side and to identify the abnormality of a signal line and the interface circuits without adding a special circuit. SOLUTION: An engine control unit 11 forms two kinds of pulse signals whose duty ratios are varied in accordance with I/O of digital information to be transmitted. The arithmetic part 16 of an automatic gearbox control unit 15 repetitively reads a binary signal from the signal line 20 in accordance with a processing program. When it detects the rise of the binary signal, a software timer after 500msec. equivalent to the intermediate value of the two kinds of duty ratios is raised, and original information is reproduced from the binary signal at time when 500msec. pass. The arithmetic part 16 detects that the rise of the binary signal is stopped for five seconds in accordance with the processing program and judges it to be communication abnormality.</p> |
