Subscriber station and method for deterministic communication in serial bus system

Abstract

A subscriber station and a method for deterministic communication in a serial bus system are provided. The user station is provided with a communication control device. The invention relates to a communication control device for controlling communication of a subscriber station with at least one other subscriber station of a bus system by generating a message on the basis of a frame and transmitting the message to a bus of the bus system and evaluating at least one signal received from the bus of the bus system on the basis of a frame in which the message is transmitted to the bus of the bus system. The bit time in the first communication stage may be different from the bit time in the second communication stage; and a pause module for evaluating at least one piece of status information output from the communication control device regarding whether a predetermined frame has been received from the bus, the pause module being designed to generate and output a transmission delay signal on the basis of the result of its evaluation, the transmission message is provided to the communication control device in a delayed or non-delayed manner.

Description

Technical Field

[0001] The present invention relates to a user station and a method for deterministic communication in a serial bus system. Background Art

[0002] For cost reasons, many vehicle manufacturers prefer bus systems over point-to-point connections. Here, for communication between technical devices, such as sensors and control devices, an increasing data transfer rate is desired. In some bus systems, technical devices should be able to communicate with each other and, if necessary, should be able to switch between different standards for the data transfer rate and / or communication between user stations of the bus system as needed.

[0003] Currently, classic CAN and / or CAN FD are used for communication between devices in vehicles and / or other technical devices, both of which are standardized in the international standard ISO11898-1:2015.

[0004] In CAN bus-based communication, the following frames are used to generate transmission signals, which are divided into an arbitration phase and a data phase. In the arbitration phase, it is negotiated between the user stations of the bus system which of the user stations of the bus system will obtain exclusive access to the bus in the next data phase and then are allowed to send their data to the bus. In the data phase, in the case of CAN FD and CAN XL, the bits of the transmission signal are generated and sent to the bus with a shorter bit time than in the arbitration phase. These bits are thus generated and sent at a higher bit rate in the data phase.

[0005] CAN FD is first used by most users in vehicles at a data bit rate of 2 Mbit / s and an arbitration bit rate of 500 kbit / s. The so-called CAN SIC transceiver (also called a transceiver) enables the use of CAN FD up to 8 Mbit / s.

[0006] In addition, CANXL can also be used, which is compatible with CANFD and is specified in ISO11898-1. With SIC and SICXL transceivers, bit rates of up to 8 Mbit / s or 20 Mbit / s can be achieved in the data phase in the case of CAN XL. On the other hand, also in the case of CAN XL, the bit rate in the arbitration phase remains at around 500 kbit / s for arbitration. In addition, in the case of CANXL, a useful data length of up to 2048 bytes can be used. The use of CANXL in actual products has currently started. This enables high data transfer rates to be achieved in vehicle bus systems currently.

[0007] However, an important requirement for the operation of autonomous or semi-autonomous transport vehicles is to maintain a predetermined maximum reception delay for each transmitted frame. This delay is also referred to as the worst-case delay. This means that the frame must arrive at the receiving user station (receiving node) at the latest after the worst-case delay. For example, the delays are caused by other frames or signals occupying the bus.

[0008] In a bus system, the above requirement can be solved by means of deterministic bus access.

[0009] For such bus access, the Ethernet transceiver 10BASE-T1S standardized in the IEEE uses a method called PLCA (Physical Layer Collision Avoidance). In PLCA, each node has a node number. All nodes send in sequence. This is called round-robin (RR) scheduling in the literature. Additionally, the PLCA method requires a master node (user station). At the beginning of a cycle, the master node sends a so-called BEACON signal, which marks the start of the cycle. In each cycle, each node is allowed to send 1 frame. The PLCA method provides determinism and allows for a fair distribution of the communication bandwidth among all nodes. However, the disadvantages are that the master node is essential, even if it poses a risk to functional safety. Another disadvantage is that the configuration of each node with a node number results in great complexity.

[0010] The arbitration in a CAN-based bus system uses the CSMA / CR method (CR = Collision Resolution) at the beginning of the frame, which resolves transmission conflicts on the bus. The conflict resolution is based on the identifier (ID) of the frame. The frame with the highest priority identifier (ID) prevails on the bus. This corresponds to strict priority scheduling. Currently, this is sufficient for many use cases in autonomous transport vehicles. However, the arbitration is not initially suitable for use cases that require deterministic bus access.

[0011] In some cases, this problem can be solved by selecting the bit rate on the CAN bus to be higher than the required bit rate, so that the CAN bus is only utilized to, for example, 50%. However, this severely limits the net data rate. In any case, the possible net data rate at maximum bus utilization cannot be achieved. Summary of the Invention

[0012] Accordingly, an object of the present invention is to provide a method and a user station for deterministic communication in a serial bus system that solve the above problems. In particular, a method and a user station for deterministic communication in a serial bus system should be provided, in the case of which user station and method, even when different communication standards and bit rates are used in the bus system, it is possible, if necessary, to implement and ensure for each individual user station in a cost-effective and reliable manner without excessive consumption: even in the case of maximum bus utilization, deterministic bus access can be carried out.

[0013] This object is solved by a user station for deterministic communication in a serial bus system having the features of claim 1. The user station has: a communication control device for controlling the communication of the user station with at least one other user station of the bus system by generating messages based on frames and sending the messages onto the bus of the bus system and evaluating at least one signal received from the bus of the bus system based on such frames, in which the bit time in a first communication phase can be different from the bit time in a second communication phase; and a pause module for evaluating at least one status information output from the communication control device regarding whether a predetermined frame has been received from the bus, wherein the pause module is designed to generate and output a transmission delay signal based on the result of its evaluation in order to delay or not delay the provision of a transmission message to the communication control device, wherein the transmission message should be sent as a message from the communication control device onto the bus.

[0014] The described design of the user station enables deterministic bus access and enables a possible net data rate at maximum bus utilization. The described user station advantageously allows 100% CAN bus utilization and at the same time allows deterministic bus access. In particular, it is thus possible to achieve both a high data bit rate such as in the case of CAN XL and to meet the requirements for applications with strict real-time requirements.

[0015] Accordingly, the described user station also provides the use of CAN even for applications with strict real-time requirements. The technology of the described user station is suitable for replacing FlexRay.

[0016] Yet another advantage results from the very low-cost and uncomplicated configuration of the user station and thus from the implementation of the method performed by the user station in the bus system.

[0017] In addition, the described user station enables at least two user stations to exist in the bus system, which two user stations send messages to the bus according to different CAN standards. Thus, for example, in addition to two CAN-XL user stations, there can additionally exist at least one other user station in the bus system that sends messages to the bus according to other / different CAN standards.

[0018] Advantageous further design options of the user station are specified in the dependent claims.

[0019] The pause module can be designed to set the transmission delay signal to a predetermined value only after the communication control device has sent N frames, and according to this predetermined value, the transmission message provided for the communication control device should be delayed from being sent to the bus, where N is a natural number greater than or equal to 1.

[0020] The user station may also have a message processing module for providing a transmission message to the communication control device, and a logic module for outputting the transmission message to the communication control device based on the determination of the pause module.

[0021] In one design option, the communication control device is designed to negotiate with other user stations in a first communication phase: which user station of the bus system will at least temporarily obtain exclusive and conflict-free access to the bus in a subsequent second communication phase.

[0022] In one design option, the pause module is designed to evaluate at least one status information related to at least one predetermined attribute of a predetermined frame.

[0023] The pause module may have a configuration buffer for storing configuration parameters of at least one predetermined attribute of a predetermined frame, where the configuration parameters are optionally available to the user station as needed.

[0024] The at least one predetermined attribute may be a predetermined frame identifier of a predetermined frame. Additionally or alternatively, the at least one predetermined attribute is a predetermined control bit with a predetermined value. Additionally or alternatively, at least one predetermined attribute is a predetermined frame format.

[0025] The user station can be a host user station, where the host user station is designed to send a predetermined frame to the bus after a predetermined period of time has passed.

[0026] It is conceivable that the pause module is also designed to evaluate at least one status information related to at least one event on the bus.

[0027] At least one event on the bus can include or be: the communication control device sees the bus in an idle condition for one bit.

[0028] At least one event on the bus can include or be: the communication control device has started receiving a signal corresponding to a frame from the bus.

[0029] At least one event on the bus can include or be: the communication control device has successfully sent a signal corresponding to the frame to the bus.

[0030] At least one event on the bus can include or be: The communication control device has recognized an error when sending a signal corresponding to the frame.

[0031] In one design, the user station is a host user station, where the host user station is designed to send a predetermined frame to the bus after the pause module has recognized a predetermined number of events on the bus, where these events include: The communication control device sees the bus in an idle state for one bit and / or the communication control device has started receiving a signal corresponding to the frame from the bus, where P is a natural number equal to or greater than 1.

[0032] The above user station can also have a signal setting block (Signalsetzblock), which is designed to change the value of the transmission delay signal after detecting at least one event, in order to delay the transmission message provided to the communication control device.

[0033] The above user station can also have a transmission / reception device, which is connected to the bus and is designed to generate a digital reception signal based on at least one signal received from the bus, where the communication control device is designed to sample and evaluate the reception signal generated by the transmission / reception device according to a predetermined frame.

[0034] At least one of the aforementioned user stations can be part of a bus system, which also has a bus and at least one of the above host user stations (Master-Teilnehmerstation), where the at least one user station and the at least one host user station are connected to each other via the bus such that these user stations can communicate with each other serially.

[0035] The above task is also solved by the method for deterministic communication in a serial bus system according to claim 18. This method is executed using a user station having a communication control device and a pause module, where the communication control device is designed to control the communication between the user station and at least one other user station of the bus system by: generating a message based on a frame and sending the message to the bus of the bus system and evaluating at least one signal received from the bus of the bus system based on the following frame, in which the bit time in the first communication phase can be different from the bit time in the second communication phase, and where the method has the steps: using the pause module to evaluate at least one status information output from the communication control device regarding whether a predetermined frame has been received from the bus, and using the pause module to generate a transmission delay signal based on the result of its evaluation, in order to delay or not delay providing a transmission message to the communication control device, where the transmission message should be sent from the communication control device as a message to the bus.

[0036] This method offers the same advantages as those mentioned previously regarding the user station.

[0037] Further possible implementations of the present invention also include combinations of features or embodiments described above or below in connection with the embodiments that are not explicitly mentioned. Here, those skilled in the art will also add individual aspects as improvements or supplements to the corresponding basic forms of the present invention. Brief Description of the Drawings

[0038] The present invention will be described in more detail below with reference to the drawings and using embodiments. Among them:

[0039] Figure 1 Shows a simplified block diagram of a bus system according to a first embodiment;

[0040] Figure 2 Shows a diagram for clarifying the structure of a message that can be sent from a user station of a bus system according to a first embodiment, where the user station does not have a host function (Masterfunktion) in the bus system;

[0041] Figure 3 Shows a diagram for clarifying the structure of a message that can be sent from a host user station of a bus system according to a first embodiment;

[0042] Figure 4 Shows a schematic block diagram of a user station of a bus system according to a first embodiment, where the user station does not have a host function in the bus system;

[0043] Figure 5 Shows Figure 4 The time curve of a digital transmission signal during the operation of the bus system at the user station, where the user station is connected to the same bus of the bus system as at least one second user station;

[0044] Figure 6 Shows Figure 4 The time curves of the bus signals CAN_H and CAN_L at the user station;

[0045] Figure 7 Shows Figure 4 The time curve of the differential voltage VDIFF of the bus signals CAN_H and CAN_L at the user station;

[0046] Figure 8 Shows Figure 4 The time curve of a digital reception signal generated by the user station according to the signal received from the bus;

[0047] Figure 9A diagram showing the status (Status) on the bus of the bus system that may occur over time during the operation of the bus system according to the first embodiment;

[0048] Figure 10 Shows the time curve of a signal for releasing or not releasing the transmission from Figure 4 of the user station to Figure 1 on the bus of the bus system; and

[0049] Figure 11 Shows a diagram for clarifying the structure of a message that can be sent from the host user station of the bus system according to the second embodiment.

[0050] In the drawings, unless otherwise specified, the same or functionally identical elements are provided with the same reference numerals. Detailed Description of the Invention

[0051] As an example, Figure 1 shows a bus system 1, which is designed in particular basically for a CAN bus system, a CANFD bus system, a CANXL bus system and / or its variants, as described below. The bus system 1 can be used in a means of transportation, in particular a motor vehicle, an aircraft, etc. or in a hospital, etc.

[0052] In Figure 1 the bus system 1 has a plurality of user stations 10, 20, 30, which are respectively connected to a bus 40 having a first bus lead 41 and a second bus lead 42. These bus leads 41, 42 can also be referred to as CAN_H and CAN_L, and are used for electrical signal transmission after coupling a dominant level or generating a recessive level or other levels for the signal input in the transmission state.

[0053] Via the bus 40, messages 45, 46 can be serially transmitted in the form of signals between the respective user stations 10, 20, 30 based on frames according to Figure 2 . If interference occurs during communication on the bus 40, as shown by the zigzag black arrows in Figure 1 , one of these user stations 10, 20, 30 can optionally send an error frame 47 (Error Frame), which has an error identifier (ErrorFlag (error flag)) and an error delimiter (ErrorDelimiter). In particular, this interference may cause: the user station 10 recognizes an error when sending messages 45, 46, which corresponds to the event E4. This interference is shown by the zigzag arrow in Figure 1 . Figure 1 The user stations 10, 20, 30 of are, for example, control devices, sensors, display devices, etc. of a motor vehicle or other technical facilities.

[0054] The user station 30 is also referred to as the master hereinafter because the user station 30 specifies, by sending a predetermined message 48 via the bus 40 according to a predetermined frame 450_B of Figure 3 , when the user stations 10, 20 are allowed to send messages 45, 46 onto the bus 40 based on the frames of Figure 2 . The predetermined frame 450_B is shown in Figure 3 and Figure 9 and is described in more detail below.

[0055] Therefore, in this embodiment, the user stations 10, 20 do not have a host function. The user stations 10, 20 are therefore also referred to as non-host user stations or slave user stations (Slave-Teilnehmerstation).

[0056] As Figure 1 shows, the user station 10 has a communication control device 11, a transmitting / receiving device 12, and a transmission waiting device 15. The user station 20 has a communication control device 21, a transmitting / receiving device 22, and a transmission waiting device 25. The user station 30 has a communication control device 31, a transmitting / receiving device 32, and a transmission waiting device 35. The transmitting / receiving devices 12, 22, 32 of the user stations 10, 20, 30 are each directly connected to the bus 40, even though this is not shown in Figure 3 .

[0057] The communication control devices 11, 21, 31 are each used to control the communication of the respective user stations 10, 20, 30 via the bus 40 with at least one other user station among the user stations 10, 20, 30 connected to the bus 40. For this purpose, the communication control devices 11, 31 create and / or read a first message 45, which is, for example, a CANFD message 45. These CANFD messages 45 are based on the CAN FD format specified in ISO11898-1:2015.

[0058] Furthermore, the communication control devices 11, 31 can also be implemented to provide or receive CAN FD messages 45 or CAN XL messages 46 from / to the associated transmitting / receiving devices 12, 32 as needed. Thus, the communication control devices 11, 31 create and read a first message 45 or a second message 46, where the first message 45 and the second message 46 are distinguished by their data transmission standards, in this case CANFD or CAN XL. The CANXL message 46 is based on the CAN XL format specified in CiA610-1 or ISO11898-1.

[0059] The communication control device 21 can be implemented similar to a conventional CAN controller according to ISO 11898-1:2015, i.e., similar to a CAN FD-tolerant classical CAN controller or a CAN FD controller. The communication control device 21 creates and reads a first message 45, e.g., a CAN FD message 45. The CAN FD message 45 can include from 0 to 64 data bytes, which are to be transmitted at a significantly faster data rate than classical CAN messages. In particular, the communication control device 21 is implemented similar to a conventional CAN FD controller.

[0060] The transmitting / receiving devices 12, 32 can be implemented to provide, as needed, or receive from the relevant communication control devices 11, 31 messages 45 in CAN FD format or messages 46 in CAN XL format.

[0061] The transmitting / receiving device 22 can be implemented similar to a conventional CAN transceiver or CAN FD transceiver according to ISO 11898-1:2015.

[0062] Additionally, there are transmission waiting devices 15, 25, 35, which are described in more detail below.

[0063] Figure 2 The basic structure of a frame 450, as provided by the communication control device 11 to the transmitting / receiving device 12 for transmission onto the bus 40, is shown for the message 45.

[0064] According to Figure 2 , the frame 450 for CAN communication on the bus 40 is divided into different communication phases 451, 452, i.e., an arbitration phase 451 (first communication phase) and a data phase 452 (second communication phase). The frame 450 has an arbitration field 453, a control field 454, a data field 455, a checksum field 456, and a frame end field 457 after a start-of-frame bit SOF. The following frame is used for the message 46, and this frame 450 has the same basic structure as the frame 450 shown in Figure 2 .

[0065] In the arbitration phase 451, by means of an identifier (ID) having, for example, bits ID28 to ID18 in the arbitration field 453, a bit-by-bit negotiation is carried out between the user stations 10, 20, 30: which user station 10, 20, 30 wants to send a message 45, 46 with the highest priority and thus obtain exclusive access to the bus 40 of the bus system 1 for transmission in the subsequent data phase 452. In the arbitration phase 451, the physical layer is used with dominant and recessive bus conditions. The physical layer corresponds to the bit transmission layer or the first layer of the well-known OSI model (Open System Interconnection model)

[0066] Only when the user station 10 acting as the sender has won arbitration and thus has exclusive access to the bus 40 of the bus system 1 for transmission as the sender, the sender of the message 45 (e.g., the user station 10) starts to send the bits of the control field 454 and the bits of the data phase 452 onto the bus 40. The same applies if the user stations 20, 30 want to send the messages 45 or 46 onto the bus 40.

[0067] In the data phase 452, in addition to a part of the control field 454, the useful data of the message 45 or the message 46 or the frame 450 in the data field 455 and the checksum field 456 are also sent.

[0068] The checksum of the data in the data phase 452 can be included in the checksum field 456. At the end of the data phase 452, the arbitration phase 451 is switched back again.

[0069] In the frame end field 457, a one-bit ACK slot is provided, in which those user stations that are currently only the receivers of the frame 450 and not the senders of the frame can confirm or not confirm the correct reception of the frame 450 from the bus 40. A one-bit ACK-Del is also provided, which is also called the ACK delimiter. A bit sequence is provided in the frame end field 457, which marks the end of the frame 450. Thus, the bit sequence at the end of the frame end field 457 is used to mark the end of the frame 450. The bit sequence cannot appear within the frame 450. Thereby, the user stations 10, 20, 30 can reliably identify the end of the frame 450.

[0070] After the frame end field 457, there follows an inter-frame space (IFS – InterFrame Space), which is not shown in Figure 2 This inter-frame space (IFS) is designed according to ISO11898-1:2015 in the case of CAN FD. The inter-frame space (IFS – InterFrame Space) has at least 3 bits.

[0071] In addition, the fields and bits mentioned are known from ISO11898-1:2015 or CiA610-1, and thus will not be described in more detail here.

[0072] Thus, in the arbitration phase 451, which is the first communication phase, the user stations 10, 30 partly use a format known from CAN / CAN-FD according to ISO11898-1:2015. However, for CANFD and CANXL, compared with CAN, the net data transfer rate can be increased in the data phase 452, which is the second communication phase, where in the case of CAN XL it can be up to 20 megabits per second. In addition, in the case of CANXL, the size of the user data per frame can be increased up to 2048 bytes.

[0073] An important point during the phase 451 at the start of the frame is the use of the known CSMA / CR method, which allows the user stations 10, 20, 30 to access the bus 40 simultaneously without corrupting higher-priority messages 45, 46. This enables other bus user stations 10, 20, 30 to be added to the bus system 1 relatively easily, which is highly advantageous.

[0074] The CSMA / CR method requires that a so-called recessive condition must exist on the bus 40, which can be overwritten by other user stations 10, 20, 30 with a dominant condition on the bus 40. In the recessive condition, a high-resistance condition exists at each user station 10, 20, 30, which, combined with the parasitic factors of the bus circuit, results in a longer time constant. This causes the maximum bit rate of the current CANFD physical layer to be currently limited to approximately 2 megabits per second in actual vehicle use. With the new CANSIC physical layer, it is also possible to reach 5 megabits per second and up to 8 megabits per second.

[0075] Figure 3 A predetermined frame 450_B is shown, which is also called the BEACON frame. Figure 1 The user station 30 (host) based on or according to the predetermined frame 450_B periodically sends a message 48 onto the bus 40. The predetermined frame 450_B is a normal CAN frame as previously described with reference to Figure 2 However, Figure 3 the frame 450_B contains at least one special or predetermined attribute 1521A.

[0076] The at least one special or predetermined attribute 1521A includes, for example: a field with a predetermined value. Thus, the predetermined frame 450_B (BEACON frame) can be a normal frame with useful data, especially a CAN FD frame. Additionally, the at least one predetermined attribute 1521A is in particular: the predetermined frame 450_B has a special or predetermined frame identifier (ID); and / or the predetermined frame 450_B has an RRS bit with a value of 1; and / or the predetermined frame 450_B is a CAN FD frame.

[0077] In the described example, the host user station of the user station 30 has two principal possibilities for sending a predefined frame 450_B (BEACON frame). According to the first possibility, the host user station sends the predefined frame 450_B in a time-controlled manner, for example, every 10 milliseconds or after any other arbitrary or suitable time period has elapsed. According to the second possibility, the host user station sends the predefined frame 450_B in an event-controlled manner. For example, in the case where the host user station has seen a predefined number P of events after sending the predefined frame 450_B. P is a natural number greater than or equal to 1. The events can be as follows.

[0078] Event E1: Seeing an idle bit (Idle-Bit) i; that is, the user station 30 (host) sees that the bit i of the bus 40 is in an "idle" condition, that is, in a standby or idling condition. When the minimum inter-frame interval (3 bits) has elapsed and no user station sends a frame onto the CAN bus, the "idle" condition occurs.

[0079] Event E2: Start of frame reception; that is, the user station 30 (host) has started receiving the frame 450 from the bus 40.

[0080] Figure 4 The basic structure of the user station 10 with a communication control device 11, a transmitting / receiving device 12, and a separately arranged transmission waiting device 15 is shown. The user station 20 is constructed in the same way as the transmission waiting device 15. The user station 30 can be constructed in a similar manner as Figure 4 shown. However, in Figure 1 the example, the transmission waiting device 35 is integrated into the communication control device 31. Therefore, the user station 30 is not described separately.

[0081] According to Figure 4 , in addition to the communication control device 11, the transmitting / receiving device 12, and the transmission waiting device 15, the user station 10 also has a microcontroller 13 assigned to the communication control device 11 and a system ASIC 16 (ASIC = Application-Specific Integrated Circuit), which can also be a system base chip (SBC), on which a plurality of functions required for the electronic device components of the user station 10 are combined. In addition to the transmitting / receiving device 12, a power supply device 17 is additionally installed in the system ASIC 16, which supplies electrical energy to the transmitting / receiving device 12. The power supply device 17 generally provides a CAN power (CAN_Supply) voltage of 5V. However, if required, the power supply device 17 can provide other voltages with other values. Additionally or alternatively, the power supply device 17 can be designed as a power source.

[0082] The transmission waiting device 15 can be arranged in a separate microcontroller (not shown), as Figure 3As shown. Alternatively, the transmission waiting device 15 may be arranged in the microcontroller 13.

[0083] The transmission waiting device 15 has a message processing module 151, a pause module 152, and a logic module 153. Modules 151, 152, and 153 create and / or process the digital signals TX_D, TX_R, TX_E, and TX_S.

[0084] The pause module 152 may be arranged in the transmission waiting device 15, as Figure 3 shown. Alternatively, the pause module 152 is assigned to the device 11, particularly arranged in the device 11. Alternatively, the pause module 152 may be arranged separately from the transmission waiting device 15, and separately from the microcontroller 13 and the device 11.

[0085] The message processing module 151 has a transmission message buffer 1511 for storing at least one transmission message 1511A, a reception message buffer 1512 for storing at least one reception message 1512A, and an evaluation block 1513. The pause module 152 has a configuration buffer 1521, a (release) signal setting block 1522, and an evaluation block 1523.

[0086] In the case of the pause module 152, in the configuration buffer 1521, predetermined frame attributes 1521A are stored as configuration parameters, and optionally, at least one configuration parameter 1521B for the event type is stored. The signal setting block 1522 is used to set the signal TX_E such that the transmission of the transmission message 1511A to the communication control device 11 is not (any longer) delayed.

[0087] The logic module 153 is designed for the logical operation (logische Verknüpfung) of signals. In Figure 4 the example, the logic module 153 is an AND component (UND-Baustein). However, the logic module 153 is not limited thereto, but may have at least one other component such that the logic module 153 satisfies its functions described below.

[0088] The predetermined frame attribute 1521A configures the transmission waiting means 15 or the pause module 152. For this purpose, the predetermined frame attribute 1521A can be set as required, especially when the user station 10 is put into operation, or stored in the configuration buffer 1521. The predetermined frame attribute 1521A determines what kind of predetermined frame 450_B the user station 10 must receive from the bus 40, so that the user station 10 is allowed to transfer the transmission message 1511A provided in the transmission message buffer 1511 to the communication control device 11, so that the user station 10 creates a corresponding TXD signal and transfers it to the transmission / reception device 12 for transmission onto the bus 40. The configuration parameter 1521B for at least one type of event is described in more detail below.

[0089] Reference is made below to Figure 9 and Figure 10 The transmission waiting means 15 will be described in even more detail.

[0090] According to Figure 4 , the system ASIC 16 especially has an application 161, which can be designed as a computer program (App) or software. Such an application is a technical application 161. The application 161 is, for example, any application in a means of transport. In particular, the application is a control device for an air conditioning facility and / or a windscreen washer facility and / or a driver assistance system, etc. For example, the windscreen washer facility controls the movement of at least one windscreen wiper (actuator) by using data from a rain sensor and / or a wind sensor and / or a speed sensor and / or a light sensor, and / or can switch on or off a warning light (actuator). However, the application 161 is not limited to one of the mentioned facilities or parts thereof.

[0091] The transmission / reception device 12 also has a transmission module 121 and a reception module 122. Even if the transmission / reception device 12 is always mentioned below, alternatively, it is also possible to arrange the reception module 122 in a separate device outside the transmission module. The transmission module 121 and the reception module 122 can be constructed like a conventional transmission / reception device 22. The transmission module 121 can especially have at least one operational amplifier and / or transistor. The reception module 122 can especially have at least one operational amplifier and / or transistor.

[0092] The transmitting / receiving device 12 is connected to the bus 40, more precisely to the first bus lead 41 of the bus for CAN_H and the second bus lead 42 of the bus for CAN_L. The voltage supply for the energy supply device 17 is carried out via at least one connection terminal not shown in the figure, for supplying electrical energy, in particular the CAN power supply voltage, to the first bus lead 41 and the second bus lead 42. The connection to the ground line or CAN_GND is achieved via a connection terminal not shown. The first bus lead 41 and the second bus lead 42 are terminated with a terminal resistor not shown.

[0093] In the transmitting / receiving device 12, the first bus lead 41 and the second bus lead 42 are connected not only to the transmitting module 121 but also to the receiving module 122, although this connection is not shown in Figure 4 for simplicity. The transmitting module 121 is also referred to as a transmitter. The receiving module 122 is also referred to as a receiver.

[0094] During the operation of the bus system 1, Figure 4 the transmitting module 121 of can serially convert the transmission signal TXD of the communication control device 11 into the corresponding signals CAN_H, CAN_L for CAN or CAN FD and into the signals CAN_XL_H, CAN_XL_L in the case of CAN XL for the bus leads 41, 42. The transmitting module 121 sends these signals onto the bus leads 41, 42 of the bus 40. The digital transmission signal TXD is based on the frame 450 according to Figure 2 as described above.

[0095] Figure 5 An example of the transmission signal TXD over time t is shown. Figure 6 Shows the signals CAN_H, CAN_L on the bus 40 generated by the transmission signal TXD from Figure 5 as described above.

[0096] According to Figure 6 the example of, at least in the arbitration phase 451, the signals CAN_H and CAN_L have the dominant and recessive bus levels 402, 401, as known from CAN. A differential signal VDIFF = CAN_H - CAN_L is formed on the bus 40, which is in Figure 7is shown for arbitration phase 451. Each bit of the signal VDIFF or CAN_H, CAN_L has a bit time t_bt1 in arbitration phase 451. In data phase 452, compared to arbitration phase 451, the bits of signals CAN_H and CAN_L in the case of CANFD and CANXL can be sent faster, i.e., with a shorter bit time t_bt2. Thus, signals CAN_H and CAN_L are distinguished for CAN FD and CAN X in data phase 452 at least by their higher bit rate compared to the conventional signals CAN_H and CAN_L.

[0097] Figure 6 the sequence of the conditions 401, 402 of signals CAN_H, CAN_L in and the resulting Figure 7 The curve of the voltage VDIFF in is only for illustrating the function of the user station 10. The sequence of the data conditions for bus conditions 401, 402 can be selected as required.

[0098] As Figure 4 shown, Figure 4 the receiving module 122 of forms a digital received signal RXD ( Figure 8 ) based on signals CAN_H and CAN_L etc. or VDIFF received from the bus 40 and passes it to the communication control device 11.

[0099] In the B_LB (idle) operating mode, the communication control device 11 has recognized the idle or standby condition of the CAN bus 40. This means that the communication control device waits for the reception of messages 45, 46. In this condition, no communication occurs on the bus 40. In other words, for Figure 8 the received signal RXD at Figure 4 the connection terminal of the communication control device 11 no signal is received or there is a logical 1 value, because the recessive level on the bus 40 corresponds to the bit value = 1 or logical 1 in the received signal RXD.

[0100] Below, reference is also made to Figure 9 and Figure 10 to describe the operating mode of the transmission waiting device 15 that is different from the current communication standards for classic CAN, for CANFD, and for CANXL. The modules and / or blocks of this device 15 can be implemented in hardware and / or software.

[0101] In Figure 4 the transmission waiting device 15, the message processing module 151, in particular its evaluation block 1513, evaluates whether the transmission message 1511A in the transmission message buffer 1511 is ready for transmission. Optionally, the evaluation block 1513 can evaluate whether a received message 1512A is stored in the received message buffer 1512.

[0102] If the transmission message 1511A is ready to be sent, the message processing module 151, in particular its evaluation block 1513, then signals its readiness by correspondingly setting the signal TX_R. In particular, the evaluation block 1513 sets the signal TX_R to logic 1. At the same time, the message processing module 151, in particular its evaluation block 1513, provides data to the communication control device 11 or transmits the transmission message 1511A as the signal TX_D. If the signal TX_S is correspondingly set and the CAN bus 40 is not occupied by other messages, the communication control device 11 transmits the data according to the frame 450 or the transmission message 1511A as the signal TXD to the CAN bus 40.

[0103] The TX_S signal is set as follows. The pause module 152 receives at least one status information ST_A from the communication control device 11. The at least one status information ST_A indicates the state or condition Z_40 on the bus 40. The (multiple) status information ST_A contains at least one information about the frames 450, 450_B received from the bus 40, and the pause module 152 reacts to it. For this purpose, the pause module 152 evaluates the at least one status information ST_A by using the configuration buffer 1521 in which the predetermined frame attributes 1521A are stored.

[0104] The pause module 152, in particular its evaluation block 1523, creates a digital signal TX_E as the result of its evaluation. The pause module 152, in particular its evaluation block 1523, outputs the signal TX_E to the logic module 153. The signal TX_E is also referred to hereinafter as the transmission delay signal TX_E. Alternatively, the signal TX_E can be referred to as the transmission release signal TX_E.

[0105] For example, TX_E = 0 means: It is not allowed to start transmitting the signal T_D or the frame 450 corresponding to the transmission message 1511A. In this example, the logical value 1 of the signal TX_E, that is, TX_E = 1, then means: It is allowed to start transmitting the frame 450 based on the signal T_D corresponding to the transmission message 1511A. If it is not allowed to start transmitting the frame 450 based on the signal T_D corresponding to the transmission message 1511A, the pause module 152 delays providing the transmission message 1511A for the communication control device 11 to the transmit / receive device 12. If it is allowed to start transmitting the frame 450 or the signal T_D according to the transmission message 1511A, the pause module 152 does not delay providing the transmission message 1511A for the communication control device 11 in the frame 450 to the transmit / receive device 12. Generally speaking, the pause module 152 can release or not release: providing and / or transmitting the said transmission message 1511A for the d communication control device 11, and / or providing for the transmit / receive device 12 to transmit to the bus 40.

[0106] The logic module 153 performs a logical operation on the signal TX_E and the digital signal TX_R and outputs the digital signal TX_S.

[0107] Only when the transmission waiting device 15 has determined that it is allowed to send the transmission message 1511A onto the bus 40, the corresponding signal TX_S is output to the communication control device 11. In the above example for the signal TX_E and the logic module 153, if it is allowed to start transmitting the frame 450 or the signal T_D corresponding to the transmission message 1511A, the transmission waiting device 15, in particular its logic module 153, outputs the signal TX_S = 1 to the communication control device 11.

[0108] The pause module 152 has a signal setting module 1522, which uses this signal setting module 1522 to set the signal TX_E according to at least one predetermined attribute 1521A of the predetermined frame 450_B, so that the transmission of the transmission message 1511A by the communication control device 11 to the transmission / reception device 12 in the frame 450 is no longer delayed. In order to determine whether the frames 450, 450_B received from the bus 40 have at least one predetermined attribute 1521A, the pause module 152, in particular its evaluation block 1523, evaluates the status information ST_A transmitted by the communication control device 11.

[0109] When the evaluation block 1523 evaluates or identifies in the status information ST_A that the predetermined frame 450_B has been received, the pause module 152, more precisely its signal setting block 1522, sets the signal TX_E. The predetermined frame 450_B is a frame having at least one predetermined attribute 1521A as described above.

[0110] If one of the following events E3 to E5 occurs, the pause module 152, more precisely its signal setting block 1522, resets the signal TX_E, in particular to 0, in order to delay the transfer of the transmission message 1511A to the device 11 or to the transmission / reception device 12 in the frame 450. As regards whether all three different events E3 to E5 or only a subset, in particular at least one of these events E3 to E5, are evaluated, this can be implementation-specific or can be configured for the user using an optional at least one type or parameter 1521B.

[0111] In order to count the events E1 to E2 in the status information ST_A, the signal setting block 1522 of the host user station can have at least one counting mechanism. The at least one counting mechanism is used to count the events E1 and E2 and thereby determine a count value, which can be reset by resetting to an initial value, in particular 0. When the predetermined frame 450_B is sent, events E3 to E5, preferably only E3 and E4, are used to reset the counter. After the reset, events E1 and E2 start counting again. Whether the counter is reset or set and whether the count is incremented or decremented is not important for the described function.

[0112] Event E3: User station 10 has successfully sent frame 450 or message 1511A to other user stations 20, 30 of bus system 1. This means that the sending user station 10 has received a reception confirmation in the ACK area (at least one bit) provided for this purpose in frame 450 from at least one receiving station. In other words, the entire frame 450 has been successfully sent.

[0113] Event E4: User station 10 has recognized an error during transmission and aborted sending the frame, or user station 10 has seen an ACK error, which means that user station 10 has not received a "no error" reception confirmation from these receiving stations in the ACK area (at least one bit) set for this purpose in frame 450.

[0114] Event E5: User station 10 has started sending frame 450 onto bus 40 based on send message 1511A.

[0115] In particular, only events E3 and E4 are used. This combination results in that the subscriber station 10 can retry sending frame 450 countless times after the subscriber station 10 loses arbitration. This is desirable and therefore advantageous, because these subscriber stations 10, 20, 30 on the bus 40 do not have a fixed transmission sequence, so arbitration occurs regularly.

[0116] Figure 9 and Figure 10 The previously described mode of operation of a subscriber station 10 in a bus system 1 over time t is explained in more detail with reference to a specific example. The following assumptions apply to this example:

[0117] A) User station 30 is the host user station and sends a predetermined frame 450_B, such as Figure 3 As shown in and previously described. The user station 30 also has the function of a slave user station. After receiving the predetermined frame 450_B, each of the user stations 10, 20, 30 is allowed to send a frame 450. This means that the bandwidth on the bus 40 is evenly distributed between the user stations 10, 20, 30. When the user station 30 has seen a total of three events of type E1 and / or E2, the user station 30 sends the predetermined frame 450_B.

[0118] B) In Figure 1 of all three user stations 10, 20, 30, the signal TX_E is reset when event E3 or event E4 occurs.

[0119] C) User station 10 wants to send two frames or send message 1511A onto bus 40 after the start.

[0120] D) User stations 20, 30 only sporadically perform transmissions.

[0121] Figure 9 Visualizes the situation or state Z_40 on bus 40 over time t for a specific example. As described above, pause module 152 forms Figure 10 the signal TX_E. For clarity, Figure 9 only the view of user station 10 is shown in

[0122] and will be described in more detail below. Accordingly, the views of user stations 20, 30 and the signal TX_E generated by user stations 20, 30 are obtained. Figure 9 In a specific example of Figure 1 , user stations 10, 20, 30 ( Figure 9 ) are initially switched on and are all ready to operate at time point T0 in

[0123] Now, all user stations 10, 20, 30 ( Figure 1 ) start waiting for the reception of the predetermined frame 450_B in order to be able to set the signal TX_E, as described previously.

[0124] First, user station 10 receives two idle bits i from bus 40 (two events E1). With the start of the next frame recognized at the start bit SOF (as described in reference Figure 2 ), user station 10 switches to reception (event E2). Since host user station 30 has recognized three events E1, host user station 30 sends the predetermined frame 450_B onto bus 40. For reasons of space, Figure 9 only two events E1 are shown in

[0125] User station 10 sets the signal TX_E to 1 after receiving the predetermined frame 450_B, as shown in Figure 10 . Since the signal is TX_E = 1, user station 10 starts transmitting (event E5). However, as described below, user station 10 loses arbitration twice. First, in arbitration A123, all user stations 10, 20, 30 participate in the arbitration, where user station 30 is allowed to send its frame 450 or send message 1511A, as shown in Figure 9As shown by A123 and TX3 in the figure. Subsequently, in arbitration A12, user stations 10 and 20 participate in the arbitration, where user station 20 is allowed to send its frame 450 or send message 1511A, as Figure 9 shown by A12 and TX2 in the figure. At the third transmission attempt, user station 10 can successfully send its frame, as Figure 9 shown by A1 and TX1 in the figure.

[0126] At time point T1, i.e., after the successful transmission (event E3), user station 10 sets the signal TX_E to 0 again, as Figure 10 shown.

[0127] With the start of the next frame identified by the start bit SOF (as described in reference Figure 2 ), user station 10 switches to receiving (event E2).

[0128] Subsequently, after receiving the predetermined frame 450_B, user station 10 sets the signal TX_E to 1, as Figure 10 shown. Since the signal is TX_E = 1, user station 10 starts to send (event E5). No arbitration occurs. Therefore, user station 10 can successfully send its second frame 450 or send message 1511A, as Figure 9 shown by A1 and TX1 in the figure.

[0129] At time point T2, i.e., after the successful transmission (event E3), user station 10 sets the signal TX_E to 0 again, as Figure 10 shown.

[0130] User station 10 then receives two idle bits i from the bus 40 (two events E1).

[0131] With the start of the next frame identified by the start bit SOF (as described in reference Figure 2 ), user station 10 switches to receiving (event E2).

[0132] In addition, after receiving the next predetermined frame 450_B, user station 10 sets the signal TX_E to 1 again, as Figure 10 shown.

[0133] Therefore, the design of user station 10 provides a very low-cost and uncomplicated configuration of user station 10 and an implementation of the method it executes in the bus system 1. The same applies to other user stations 20 and 30.

[0134] Figure 11 Shows the predetermined frame 450_B1 that can be generated by the host user station according to the second embodiment.

[0135] A cycle counter 4501 is included in a predetermined frame 450_B1, which is in particular a count value. The host user station is designed to increment the cycle counter 4501 cyclically in successive predetermined frames 450_B1.

[0136] The user stations 10, 20, 30 can then be configured such that they send different numbers of frames 450 onto the bus 40 in different cycles (i.e., depending on the count value of the cycle counter).

[0137] In this way too, the relationship between determinism and arbitration or priority-based transmission access in the bus system 1 can be configured.

[0138] According to a third embodiment, the transmission waiting means 15 of at least one user station 10 of the bus system 1 is designed to sequentially transmit up to N frames before the means 15 sets its signal TX_E = 0. N is a configurable parameter. N is a natural number greater than or equal to 1.

[0139] Thus, after receiving the predetermined frame 450_B, the user stations 10, 20, 30 can successively transmit up to N frames 450. A reasonable value range for N is from 1 to 10, since this also creates or increases the opportunity for other user stations in the bus system 1 to transmit frames 450.

[0140] In this way, one of the user stations 10, 20, 30 can be allowed to send burst messages (English term: Bursts). This is particularly advantageous if one user station mainly sends short messages compared to other user stations. This avoids unfairness in the allocation of the available communication bandwidth in the bus system 1.

[0141] According to a fourth embodiment, there is not only one host user station in the bus system 1.

[0142] Thus, there are, for example, two or more host user stations. The second or third, etc. host user stations can act as standby host user stations. In particular, the user station 20 is a standby host user station and the user station 30 is a host user station.

[0143] The standby host user station is designed to identify whether the bus 40 has received the predetermined frame 450_B at least once within a predetermined time T_C. The predetermined time T_C can also be referred to as the timeout time. The predetermined time T_C can be stored in the configuration buffer 1521 as a configuration parameter 1521B.

[0144] If the standby host user station does not receive the predetermined frame 450_B from the bus 40 at least once within the predetermined time T_C, the standby host user station starts to send the predetermined frame 450_B on behalf of the host user station from now on until the host user station is ready to operate again. In this case, the standby host user station receives the predetermined frame 450_B from the host user station on the bus 40 again.

[0145] In this way, the fault reliability of the communication in the bus system 1 is improved.

[0146] All the design schemes of the user stations 10, 20, 30, the bus system 1, and the methods implemented therein described previously can be used individually or in all possible combinations. In particular, all the features of the previously described embodiments and / or their modifications can be combined in any way. Additionally or alternatively, in particular, the following modifications are conceivable.

[0147] Although the present invention has been described above by way of example of a CAN bus system, the present invention can be applied in each communication network and / or communication method in which two different communication phases are used, and in the two different communication phases, the bus conditions generated for different communication phases are different.

[0148] In particular, the bus system 1 according to these embodiments can be a communication network in which data can be serially transmitted at two different bit rates. A favorable but not necessary prerequisite is that in the bus system 1, at least within a specific time period, exclusive and conflict - free access of the user stations 10, 20, 30 to the common channel is guaranteed.

[0149] The number and arrangement of the user stations 10, 20, 30 in the bus system 1 of these embodiments are arbitrary. In particular, the user station 20 in the bus system 1 can be omitted. There may be one or more user stations 10 or 30 in the bus system 1. It is conceivable that all the user stations in the bus system 1 are designed to be the same, that is, only user stations 10 or only user stations 30 exist.

Claims

1. A subscriber station (10; 20; 30) for deterministic communication in a serial bus system (1), the subscriber station comprising: A communication control device (11; 21; 31) for controlling the communication of a user station (10; 20; 30) with at least one other user station (20; 30; 10) of the bus system (1) by generating a message (45; 46) based on a frame (450) and sending the message (45; 46) to a bus (40) of the bus system (1) and evaluating at least one signal (VDIFF; RXD) received from the bus (40) of the bus system (1) based on a frame (450) in which a bit time (t_bt1) in a first communication phase (451) can differ from a bit time (t_bt2) in a second communication phase (452); and A pause module (152) for evaluating at least one status information (ST_A) outputted from the communication control device (11; 21; 31) regarding whether a predetermined frame (450_B) has been received from the bus (40), The pause module (152) is designed to generate and output a transmission delay signal (TX_E) based on the result of its evaluation so as to provide a transmission message (1511A) to the communication control device (11; 21; 31) with or without delay, wherein the transmission message (1511A) should be sent from the communication control device (11; 21; 31) as a message (45; 46) to the bus (40).

2. The user station (10; 20; 30) according to claim 1, The pause module (152) is designed to set the transmission delay signal (TX_E) to a predetermined value only after the communication control device (11; 21; 31) has transmitted N frames (450), according to which the transmission message (1511A) provided to the communication control device (11; 21; 31) should be delayed to be transmitted to the bus (40), and Where N is a natural number greater than or equal to 1.

3. The user station (10; 20; 30) according to claim 1 or 2, further comprising: a message processing module (151) for providing the communication control device (11; 21; 31) with the transmission message (1511A), and A logic module (153) for outputting the send message (1511A) to the communication control device (11; 21; 31) based on the determination of the pause module (152).

4. A user station (10; 20; 30) according to any one of the preceding claims, wherein The communication control device (11; 21; 31) is designed to negotiate with other user stations (10; 20; 30) in a first communication phase (451) as to which user station (10, 20, 30) of the bus system (1) is to at least temporarily obtain exclusive, conflict-free access to the bus (40) in a subsequent second communication phase (452).

5. A user station (10; 20; 30) according to any of the preceding claims, wherein the pause module (152) is designed to evaluate at least one state information (ST_A) associated with at least one predetermined attribute (1521A) of a predetermined frame (450_B).

6. A user station (10; 20; 30) according to claim 5, wherein the pause module (152) has a configuration buffer (1521) for storing configuration parameters of at least one predetermined attribute (1521A) of the predetermined frame (450_B), and wherein the configuration parameters are selectable for the user station (10; 20; 30) as needed.

7. A user station (10; 20; 30) according to claim 5 or 6, wherein the at least one predetermined attribute (1521A) is a predetermined frame identifier of the predetermined frame (450_B) and / or a predetermined control bit having a predetermined value and / or a predetermined frame format.

8. The user station (30) according to any one of the preceding claims, wherein the user station (30) is a host user station, and The host user station (30) is designed to send the predetermined frame (450_B) to the bus (40) after a predetermined time period has passed.

9. A user station (30) according to any of the preceding claims, wherein the pause module (152) is also designed to evaluate at least one status information (ST_A) related to at least one event (E1; E2; E3; E4; E5) on the bus (40).

10. The user station (10; 20; 30) according to claim 9, wherein At least one event (E1) on the bus (40) includes: the communication control device (11; 21; 31) sees that the bus (40) is in an idle state for a bit (i).

11. The user station (10; 20; 30) according to claim 9 or 10, wherein at least one event (E2) on the bus (40) comprises: The communication control device (11; 21; 31) has started receiving a signal (VDIFF; RXD) corresponding to the frame (450) from the bus (40).

12. The user station (10; 20; 30) according to any one of claims 9 to 11, wherein at least one event (E3) on the bus (40) comprises: The communication control device (11; 21; 31) has successfully transmitted a signal (TXD; CAN_H, CAN_L) are sent to the bus (40).

13. The user station (10; 20; 30) according to any one of claims 9 to 12, wherein the at least one event (E4) on the bus (40) comprises: The communication control device (11; 21; 31) sends a signal (TXD; CAN_H, CAN_L).

14. The user station (30) according to any one of claims 9 to 13, wherein the user station (30) is a host user station, and wherein the host user station (30) is designed to send the predetermined frame (450_B) to the bus (40) after the pause module (152) has identified a predetermined number (P) of events (E1; E2) on the bus (40) according to any one of claims 11 or 12, Where P is a natural number equal to or greater than 1.

15. A user station (10; 20; 30) according to any one of the preceding claims, further comprising a signal setting block (1522), which is designed to change the value of the transmission delay signal (TX_E) after detecting at least one event (E3; E4; E5) according to any one of claims 13 to 14, so as to delay providing a transmission message (1511A) for the communication control device (11; 21; 31).

16. User station (10; 20; 30), The subscriber station also has a transmitting / receiving device (12; 32) which is connected to the bus (40) and is designed to generate a digital receiving signal (RXD) as a function of at least one signal (VDIFF) received from the bus (40). in, The communication control device (11; 21; 31) is designed to sample and evaluate a reception signal (RXD) generated by the transmission / reception device (12; 32) according to a predetermined frame (450; 460).

17. A bus system (1) comprising: a bus (40), and At least one of the user stations (10; 20; 30) according to any of the preceding claims, and At least one host user station (20; 30) according to any one of claims 9 or 15, The at least one user station (10; 20; 30) and the at least one host user station (20; 30) are connected to one another via the bus (40) in such a way that the user stations (10; 20; 30; 50) can communicate with one another serially.

18. A method for deterministic communication in a serial bus system (1), wherein the method is performed using a user station (10; 20; 30) having a communication control device (11; 21; 31) and a pause module (152), wherein the communication control device (11; 21; 31) is designed to control the communication of the user station (10; 20; 30) with at least one other user station (20; 30; 10) of the bus system (1) by generating a message based on a frame (450); (45; 46) and sending the message (45; 46) to a bus (40) of the bus system (1) and evaluating at least one signal (VDIFF; RXD) received from the bus (40) of the bus system (1) based on a frame (450) in which a bit time (t_bt1) in a first communication phase (451) can differ from a bit time (t_bt2) in a second communication phase (452), and wherein the method comprises the steps of: The pause module (152) evaluates at least one status information (ST_A) outputted from the communication control device (11; 21; 31) regarding whether a predetermined frame (450_B) has been received from the bus (40), and The pause module (152) is used to generate a transmission delay signal (TX_E) based on the result of its evaluation so as to delay or not delay the provision of a transmission message (1511A) to the communication control device (11; 21; 31), wherein the transmission message (1511A) should be sent from the communication control device (11; 21; 31) as a message (45; 46) to the bus (40).

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