| 摘要 |
For data transmission via a data bus in the form of a single-wire bus, to which several stations are connected in parallel, data bits are transmitted singly in a periodic sequence of signals, whereby each period has at least one section in which the transmitted signal indicates the occupancy of the data bus, a further section in which the transmitted signal indicates the value of the data bit, and a section without data, preferably with high potential in the case of an electric data bus, to which the data generated by the individual stations is linked by an OR function. The durations of the individual sections have fixed periods with respect to one another, and from the signal transfer at the beginning of every two successive periods the duration of the period in each station is determined and from the the position of the individual sections is determined in which the signal is sampled on the data bus and the value of the transmitted data bit is determined. In a preferred embodiment, at the beginning of each period a signal transfer is created on the data bus permanently, outside of a data transmission, so that a first section of the period represents a permanent clock pulse on the data bus which synchronizes all the stations. For the signal which indicates the occupancy of the data bus a section is reserved after this which is then followed again by the time period for the data bit. This makes it possible to achieve a data transmission between stations the internal clocks of which exhibit considerable differences, and yet multimaster operation is still possible.
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