摘要:
The invention refers to a method for monitoring a communication media access schedule of a communication controller (5) of a communication system (1) by means of a bus guardian (6). The communication system (1) comprises a communication media (2) and nodes (3) connected to the communication media (2). Each node (3) comprises a communication controller (5) and a bus guardian (6) assigned to the communication controller (5). Messages are transmitted among the nodes (3) across the communication media (2) based on a cyclic time triggered communication media access scheme. In order to provide a mechanism which allows the bus guardian (6) to monitor the communication media access scheme of the communication controller (5) even during startup of the communication it is suggested, that the bus guardian (6) has a priori knowledge about possible deviations from the communication media access schedule during startup of the communication and that the bus guardian (6) during startup makes use of the a priori knowledge to distinguish between an allowed deviation and a forbidden deviation caused by a failure of the communication controller (5).
摘要:
A method and a bit stream decoding unit for bit stream decoding has a bit stream comprising a number of consecutive samples. In order to provide for rapid and, in particular, reliable decoding of the bit stream, a detection window comprising a number of samples is defined and the detection window is positioned at certain positions on the bit stream in order to comprise certain samples with respective sample values. A majority voting is applied to the sample values in the detection window and, in dependence on the result of the majority voting, the bit stream is decoded and respective bit values are generated.
摘要:
The invention refers to one of a number of nodes of a communication system. The nodes are connected to a communication media for transmitting data among the nodes. Said one node comprises a communication controller, across which the node is connected to the communication media, and a bus guardian for controlling access of the communication controller to the communication media. In order to provide a cheap but nevertheless reliable way for monitoring the synchronized clock signal of a node of a communication system and in particular for detecting deviations of the synchronized clock signal it is suggested that a synchronized clock signal from the communication controller is made available to the bus guardian, and that the bus guardian comprises means for monitoring the synchronized clock signal using a bus guardian internal clock signal, which is generated by means of an electronic circuit and which is less accurate than the synchronized clock signal to be monitored.
摘要:
The invention concerns a network comprising an interconnecting network and several network nodes that are coupled to said interconnecting network and are designed to adapt their local communication time schedule to the communication time schedule of at least one other network mode, prior to being integrated as active network nodes. A network node to be integrated checks the activity of other network nodes and if no activity is identified, sends out positional messages for other network nodes, said message being fixed by predetermination in its communication time schedule. If a network node cannot be integrated as a reference node, it can only be integrated as an active node if it adapts its local communication time schedule to that of the reference node after receiving positional messages and if a check as to whether its own communication time schedule agrees with the communication time schedules of at least some of the active network nodes proves positive.
摘要:
The invention concerns a network comprising an interconnecting network and several network nodes that are coupled to said interconnecting network and are designed to adapt their local communication time schedule to the communication time schedule of at least one other network mode, prior to being integrated as active network nodes. A network node to be integrated checks the activity of other network nodes and if no activity is identified, sends out positional messages for other network nodes, said message being fixed by predetermination in its communication time schedule. If a network node cannot be integrated as a reference node, it can only be integrated as an active node if it adapts its local communication time schedule to that of the reference node after receiving positional messages and if a check as to whether its own communication time schedule agrees with the communication time schedules of at least some of the active network nodes proves positive.
摘要:
Receiver for receiving a data stream via a data bus, which receiver samples the bits of the data stream in an over-sampling process, in which n bit strobe offsets are used and n data sets with i bits are sampled,—applies a decision criterion for identifying those data sets with correct bit values. This decision uses checksum CRC,—selects one of the identified data sets with correct bit values and—uses the bit strobe offset, which was used for receiving the selected data streams, for receiving the data stream. In this way the multiphase clock with optimal phase shifts is selected.
摘要:
In order to carry out in a communication system (1) a temporal synchronization of clocks in a particularly rapid and efficient manner, a method is proposed which has the following steps: acquiring state values which are dependent on a time base (10); filing each acquired state value at a position in a first list L comprising (k+1) positions, if the acquired state value is smaller than or equal to the (k+1) smallest element of the list L, where k is a predefinable error tolerance; filing the acquired state value at a position in a second list H comprising (k+1) positions, if the acquired state value is greater than or equal to the (k+1) greatest element of the list H; forming a mean value from the (k+1) smallest element of the list L and the (k+1) greatest element of the list H, if the number of acquired state values is greater than or equal to (2k+2); determining a correction value as a function of the mean value; and correcting a current state value of the clocks that are to be synchronized.
摘要:
The invention describes a method for the monitoring and management of data traffic in a communication system with several communication nodes which communicate via interfaces monitored by a bus monitor, comprising the following steps:a) provision of a predefined communication time schedule for all communication nodes,b) initialization of the bus monitor,c) synchronization of the communication time schedule of the bus monitor with the predefined communication time schedule executed by the communication nodes in a distributed arrangement, the synchronization taking place on the basis of activities observed at the interfaces,d) monitoring of the activities of the communication nodes by the bus monitor,e) comparison of the activities with the predefined communication time schedule, andf) deactivation of the interface for any communication node for which an activity not compatible with the predefined communication time schedule has been detected. A circuit arrangement and its use are also described.
摘要:
A time-triggered communication system in a dual-channel network of singlechannel architecture, wherein in each case one communication controller (2, 6) is assigned to one channel, and two corresponding communication controllers (2, 6) communicate with one another via an inter-channel interface (1a, 1b). Said inter-channel communication contains information about limiting points (G1, G2 . . . G12) of a time path. A limiting point (G1, G2 . . . G12) is, for example, the point in time when a cycle starts. The interchange of limiting points enables the temporal offset of the two channels to be determined as well as a correction value. After every two cycles also the rate error of the local clocks can be ascertained and a suitable correction value determined. The reliability of safety-relevant networks is increased by the time-triggered communication system described hereinabove.
摘要:
A dual-channel network with in each case one communication controller (2, 6) for each of the two channels (A, B). In order to ensure that the two channels (A, B) operate on a temporally matched basis, an exchange of current states (“ready, “abort”) takes place via an external or an on-chip interface (1a, 1b). The cold start operation is carried out only if, and so long as, both communication controllers are in the “ready” state.