Nippondenso Co., Ltd.

Tengo Fujii

Hideaki Ishihara

Akihiro Sasaki

Yasushi Kanda

Kouichi Maeda

Nobutomo Takagi

A communication apparatus is used in a communication system, having a communication line, where an operation timing in each of the communication apparatus is coupled to the communication line and synchronized with the received signals in each of the communication apparatus. This communication apparatus comprises a signal-chip microprocessor having a central processing unit for executing main and interruption processing, a register storing data to be transmitted next, an output buffer for transmitting the transmission data, and an edge detector for detecting an edge in the communication line. The output buffer is directly responsive to an edge detection circuit, so that the transmission data can be immediately transmitted in response to the detection of an edge without a variable delay time caused by the operation condition which may be varied by the interruption processing or like.

Communication apparatus with collision detection and edge detection for

In a receiving device, when a communication signal, which changes between low level and high level, is received via a filter circuit, an occurrence of an edge of the filtered received signal is monitored. Upon detection of the edge, a type of the edge, that is, whether the edge is a leading or trailing edge, is determined. Depending on the type of the edge, one of preset times prestored corresponding to types of the edges, is selected and starts to be measured. When the selected preset time elapses, the filtered received signal is sampled. With this arrangement, even when a filtering time of the filter circuit differs depending on a type of the edge of the communication signal, a constant sampling timing relative to the communication signal can be achieved irrespective of whether the detected edge is the leading or trailing edge.

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Anjo, Japan

Tengo Fujii