Media access control method for a bus system and communication apparatus

Abstract

The invention relates to a media access control method for controlling the access of a subscriber station (13) of a bus system (11) to a first channel (15) of the bus system (11) jointly used by several subscriber stations (13), wherein in the method at least one enabling interval ([delta]T1, [delta]T2, [delta]T3, [delta]T4, [delta]T5) is specified for the subscriber station (13), within which enabling interval the subscriber station (13) has exclusive access to the first channel (15). In order to specify a media access control method, wherein large amounts of data can be transmitted relatively quickly and real-time conditions can be maintained when messages are transmitted by means of the bus system (11), it is proposed that the access to a second channel (19) used by several subscriber stations (13) be controlled using the method, wherein the second channel (19) is enabled only within the enabling interval ([delta]T1, [delta]T2, [delta]T3, [delta]T4, [delta]T5) during which access by the subscriber station (13) is enabled.

Description

technical field [0001] The invention relates to a medium access control method for controlling the access of subscriber stations of a bus system to a first channel of the bus system shared by a plurality of subscriber stations, wherein at least one release time is predetermined for the subscriber stations in the method Interval (Freigabe interval) during which the subscriber station has exclusive access to the first channel. Furthermore, the invention relates to a subscriber station and a control element, in particular a CAN controller, for carrying out such a method. Background technique [0002] For example, laid-open document DE 100 00 305 A1 discloses a “controller area network” (CAN) and a CAN extension called “time-triggered CAN” (TTCAN). The medium access control method used in CAN is based on bit-by-bit arbitration. In this bit-by-bit arbitration, a plurality of subscriber stations can simultaneously transmit data via the channels of the bus system without thereby ...

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Problems solved by technology

But here the communication with the CAN protocol must be interrupted for a while

If, for example, due to an error, the bus system can no longer be operated according to the CAN protocol, resulting in a stop of the bus system

Furthermore, the real-time properties of CAN are affected by the transmission of relatively large data blocks, which leads to a significant delay in the subsequent transmission according to the CAN protocol

Therefore, this method is not suitable both for programming the control unit at the end of the manufacturing process of the motor vehicle or control unit and for use during operation of the motor vehicle

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