| 摘要 |
<p>PURPOSE: To ideally eliminate the time loss that is caused by occurrence of the abnormality in an asynchronous serial communication environment where the data of different transmission rates are transferred together. CONSTITUTION: The synchronous serial data communication is carried out for diagnoses of faults between a diagnostic tool 5 and an electronic controller 1 or 2 via a communication line 3. In such a data communication mode, the data are first transferred at a low rate between the tool 5 and the device 1 or 2. Then the transmission rate is switched to a high rate and various data are transferred. If the abnormality of communication occurs, the transfer of data is carried out again at a low transmission rate. That is, an edge detection terminal is added to a communication circuit 17 to detect an edge of data that are sampled at a low rate. Then the abnormality of communication is decided if the difference between the first edge detection time and the next one is smaller than the 1-bit time of the low transmission rate data. Furthermore, the data are received again through the sampling of a low rate and based on the next edge detection timing.</p> |
