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 subscriber station for controlling communication of the subscriber station with at least one other subscriber station of a bus system by generating a message on the basis of a frame and sending 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, in which the pause module is designed to generate and output a transmission delay signal on the basis of the result of the evaluation thereof in order to delay or not delay the provision of a transmission message to the communication control device, wherein the transmission message is to be transmitted from the communication control device as a message to the bus.

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 increasingly high 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 of data transfer rate and / or communication between user stations for 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 be 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 CAN FD and is specified in ISO11898-1. With SIC and SICXL transceivers, bit rates up to 8 Mbit / s or 20 Mbit / s can be achieved in the case of CAN XL in the data phase. On the other hand, also in the case of CAN XL, the bit rate in the arbitration phase remains at around 500 kbit / s to achieve 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 at present.

[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 that occupy 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 referred to as 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, arbitration is initially not 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 user station in a non-consumptive, cost-effective and reliable manner that even in the case of maximum bus utilization, deterministic bus access can be carried out.

[0013] This task 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 a message based on a frame and sending the message onto the bus (40) of the bus system and evaluating at least one signal received from the bus of the bus system based on such a frame, in which the bit time in the first communication phase can be different from the bit time in the second communication phase; and a pause module for evaluating at least one status information output from the communication control device, 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 from the communication control device as a message onto the bus.

[0014] The described design of the user station enables deterministic bus access without the host user station specifying when transmission is allowed. By this decentralized method, the user station can ensure high communication security very cost-effectively.

[0015] 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 high data bit rates such as in the case of CAN XL and to meet the requirements for applications with strict real-time requirements.

[0016] In addition, partial deterministic bus access of the described user station is also possible in a bus system in which not all user stations on the bus are designed for deterministic bus access.

[0017] Furthermore, the described user station is 100% compatible with existing CAN user stations. This enables a very cost-effective and resource-efficient migration of existing CAN bus systems to the described technology. The described user station also allows for at least one user station in the bus system that can send messages onto the bus according to different CAN standards. Thus, in addition to two CAN-XL user stations, there may also be, for example, at least one other user station in the bus system that sends messages onto the bus according to other / different CAN standards.

[0018] Therefore, even for applications with strict real-time requirements, the described user station enables the use of CAN. The technology of the described user station is suitable for replacing FlexRay.

[0019] Another advantage results from the very resource-efficient and uncomplicated configuration of the user station and thus from the implementation of the method performed by the user station in the bus system. The reason is that in a CAN bus system, only one scalar parameter is used for each CAN user station. This means that the system designer can use only one configuration parameter for each CAN user station to arbitrarily set the behavior on the CAN bus regarding the desired metrics of strict priority-based transmission or determinism.

[0020] Advantageous further design options of the user station are specified in the dependent claims.

[0021] 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, according to which the transmission of the transmission message provided for the communication control device to the bus should be delayed, where N is a natural number greater than or equal to 1.

[0022] The user station may also have a transmission message waiting device that has a pause module. Additionally or alternatively, the pause module can be designed to determine whether the transmission of the transmission message to the bus should be delayed or not.

[0023] 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.

[0024] In one design option, the communication control device is designed to negotiate with other user stations in a first communication phase which user station in the bus system will obtain at least temporarily exclusive and collision-free access to the bus in a subsequent second communication phase.

[0025] It is conceivable that the pause module is designed to evaluate at least one status information related to at least one event on the bus and configuration parameters.

[0026] The pause module may have a configuration buffer for storing configuration parameters that are optionally selectable for the user station as needed, and optionally for storing configuration parameters that describe at least one type of at least one event.

[0027] At least one event on the bus may 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 may 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 may 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 may include or be: the communication control device has identified an error when sending a signal corresponding to the frame.

[0031] At least one event on the bus may include or be: the communication control device has started sending a signal corresponding to a frame.

[0032] In one design, the aforementioned user station further has a counting mechanism for counting the at least one event, wherein the counting mechanism is designed to: count all events that occur in the at least one status information output by the communication control device, and wherein if the number of events counted by the counting mechanism is equal to the configuration parameter, the pause module changes the value of the transmission delay signal so as not to delay providing a transmission message to the communication control device.

[0033] In one design, the pause module is designed to increase the count value of the counting mechanism after detecting one of the aforementioned events, wherein the pause module is designed to reset the count value of the counting mechanism after detecting one of the aforementioned events and change the value of the transmission delay signal so as to delay providing a transmission message to the communication control device.

[0034] The aforementioned user station may further have a transmit / receive device connected to the bus and designed to generate a digital receive signal based on at least one signal received from the bus, wherein the communication control device is designed to sample and evaluate the receive signal generated by the transmit / receive device according to a predetermined frame.

[0035] At least two of the aforementioned user stations can be part of a bus system that also has a bus, where at least two of the user stations are connected to each other via the bus such that the user stations can communicate with each other serially.

[0036] The above task is also solved by the method for deterministic communication in a serial bus system according to claim 17. The 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 of the user station with 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 of evaluating at least one status information output from the communication control device using the pause module and generating a transmission delay signal using the pause module 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, where the transmission message should be sent as a message from the communication control device to the bus.

[0037] This method provides the same advantages as those mentioned previously regarding the user stations.

[0038] 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. Description of the Drawings

[0039] The present invention will be described in more detail below with reference to the drawings and using embodiments. Among them:

[0040] Figure 1 A simplified block diagram of a bus system according to a first embodiment is shown;

[0041] Figure 2 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 is shown;

[0042] Figure 3 A schematic block diagram of a user station of a bus system according to a first embodiment is shown;

[0043] Figure 4 A time curve of a digital transmission signal during the operation of a bus system at a user station is shown, where the user station and at least one second user station are connected to the same bus of the bus system;

[0044] Figure 5Shows the time curves of the bus signals CAN_H and CAN_L at the user station according to the first embodiment;

[0045] Figure 6 Shows the time curves of the differential voltage VDIFF of the bus signals CAN_H and CAN_L at the user station according to the first embodiment;

[0046] Figure 7 Shows the time curves of the digital received signals generated by the user station based on the signals received from the bus;

[0047] Figure 8 Shows a diagram of the conditions (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; and

[0048] Figure 9 Shows for releasing or not releasing the signal for transmission from the Figure 3 user station to the Figure 1 bus system on the bus.

[0049] In the drawings, unless otherwise specified, the same or functionally identical elements are provided with the same reference numerals. Detailed Description

[0050] As an example, Figure 1 shows a bus system 1, which is designed especially 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, especially in a motor vehicle, an aircraft, etc., or in a hospital, etc.

[0051] 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 for signal input or generating a recessive level or other levels in a transmission condition.

[0052] Via the bus 40, messages 45, 46 can be serially transmitted in the form of signals between the respective user stations 10, 20, 30. If interference occurs when communicating on the bus 40, such as through Figure 1As shown by the jagged bold arrows, one of these user stations 10, 20, 30 can optionally send an error frame 47 (ErrorFrame), which has an error identifier (ErrorFlag (error flag)) and an error delimiter (ErrorDelimiter). In particular, this interference may be event E4, based on which one of the user stations 10, 20, 30 has recognized an error when sending or receiving messages 45, 46. Figure 1 The user stations 10, 20, 30 are, for example, control devices, sensors, display devices, etc. of motor vehicles or other technical facilities.

[0053] As Figure 1 shown, 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 an optional transmission waiting device 25. The user station 30 has a communication control device 31, a transmitting / receiving device 32, and an optional 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 the figure.

[0054] The communication control devices 11, 21, 31 are respectively used to control the communication of the corresponding 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.

[0055] In addition, 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. Therefore, 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.

[0056] 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.

[0057] The transmitting / receiving devices 12, 32 can be implemented to provide or receive, as needed, messages 45 in CANFD format or messages 46 in CAN XL format from / to the relevant communication control devices 11, 31.

[0058] The transmitting / receiving device 22 can be implemented similar to a conventional CAN transceiver or a CAN FD transceiver according to ISO 11898-1:2015.

[0059] Additionally, there are transmission waiting devices 15, 25, 35, which are described in more detail below.

[0060] Figure 2 The basic structure of a frame 450 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.

[0061] 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 Figure 2 frame 450 shown in

[0062] 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 the messages 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)

[0063] 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 only if the user station 10 as the sender has won the arbitration and thus has exclusive access to the bus 40 of the bus system 1 for transmission. This also applies if the user stations 20, 30 want to send the messages 45 or 46 onto the bus 40.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] After the frame end field 457, there follows an inter-frame space (IFS – InterFrame Space), which is not shown in Figure 2 The inter-frame space (IFS) is designed according to ISO11898-1:2015 in the case of CANFD. The inter-frame space (IFS – Inter Frame Space) has at least 3 bits.

[0068] In addition, the fields and bits mentioned are known from ISO11898-1:2015 or CiA610-1 and are therefore not described in more detail here.

[0069] Thus, in the arbitration phase 451, which is the first communication phase, the user stations 10, 30 partially use a format known from CAN / CAN-FD according to ISO11898-1:2015. However, for CANFD and CANXL, compared to CAN, the net data transfer rate can be increased in the data phase 452, which is the second communication phase, where it can be up to 20 megabits per second in the case of CAN XL. In addition, in the case of CANXL, the size of the user data per frame can be increased up to 2048 bytes.

[0070] 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. As a result, it is possible to relatively easily add other bus user stations 10, 20, 30 to the bus system 1, which is highly advantageous.

[0071] The CSMA / CR method requires that there must be a so-called recessive condition 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, there is a high-resistance condition 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 achieve 5 megabits per second and up to 8 megabits per second.

[0072] Figure 3 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 identically to the transmission waiting device 15. The user station 30 can be constructed in a similar manner as Figure 3 shown. However, according to Figure 1 the transmission waiting device 35 is integrated into the communication control device 31. Therefore, the user station 30 is not described separately.

[0073] According to Figure 3, in addition to the communication control device 11, the transmission / reception device 12, and the transmission waiting device 15, the user station 10 also has a microcontroller 13 to which the communication control device 11 is assigned, and a system ASIC 16 (ASIC = application-specific integrated circuit), which can also be a system basis chip (SBC), on which multiple functions required by the electronic device components of the user station 10 are combined. In addition to the transmission / reception device 12, an energy supply device 17 is additionally installed in the system ASIC 16, which supplies electrical energy to the transmission / reception device 12. The energy supply device 17 typically provides a CAN power supply (CAN_Supply) voltage of 5V. However, if necessary, the energy supply device 17 can provide other voltages with other values. Additionally or alternatively, the energy supply device 17 can be designed as a power supply.

[0074] The transmission waiting device 15 can be arranged in a separate microcontroller (not shown), as Figure 3 shown. Alternatively, the transmission waiting device 15 can be arranged in the microcontroller 13.

[0075] The transmission waiting device 15 has a message processing module 151, a pause module 152, and a logic module 153. Modules 151, 152, 153 create and / or process the digital signals TX_D, TX_R, TX_E, and TX_S.

[0076] The pause module 152 can be arranged in the transmission waiting device 15, as Figure 3 shown. Alternatively, the pause module 152 is assigned to the device 11, especially arranged in the device 11. Alternatively, the pause module 152 can be arranged separately from the transmission waiting device 15, and separately from the microcontroller 13 and the device 11.

[0077] 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 counting mechanism 1522, and an evaluation block 1523.

[0078] In the case of the pause module 152, configuration parameters 1521A are stored in the configuration buffer 1521, and optionally, the type 1521B of the event is stored as at least one other configuration parameter. The counting mechanism 1522 is used for counting and thereby determining a count value 1522A, which can be reset to an initial value, especially 0, by resetting.

[0079] The logic module 153 is designed for the logical operation (logische Verknüpfung) of signals. In Figure 3In 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 fulfills its functions described below.

[0080] The configuration parameter 1521A configures the transmission waiting device 15 or the pause module 152. For this purpose, the configuration parameter 1521A can be set as required, especially when the user station 10 is put into operation. The configuration parameter 1521A determines how long the user station 10 has to wait until it is allowed to transmit the transmission message 1511A provided in the transmission message buffer 1511. The configuration parameter 1521A can also be referred to as TX pause. The configuration r related to at least one type 1521B of events is described in more detail below.

[0081] Reference is made below to Figure 8 and Figure 9 The transmission waiting device 15 will be described in even more detail.

[0082] According to Figure 3 , the system ASIC 16 in particular 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 vehicle. 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.

[0083] The sending / receiving device 12 also has a sending module 121 and a receiving module 122. Even if the sending / receiving device 12 is always mentioned below, alternatively it is also possible to arrange the receiving module 122 in a separate device outside the sending module. The sending module 121 and the receiving module 122 can be constructed like a conventional sending / receiving device 22. The sending module 121 can in particular have at least one operational amplifier and / or transistor. The receiving module 122 can in particular have at least one operational amplifier and / or transistor.

[0084] 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 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.

[0085] 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 3 for simplicity. The transmitting module 121 is also referred to as a transmitter. The receiving module 122 is also referred to as a receiver.

[0086] During the operation of the bus system 1, Figure 3 the transmitting module 121 of Figure 2 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 4 as described above. Figure 5 An example of the transmission signal TXD over time t is shown. Figure 4 The signals CAN_H, CAN_L on the bus 40 generated from the transmission signal TXD of

[0087] According to the example of Figure 5 , 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 Figure 6is 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 for CAN FD and CAN X are distinguished in data phase 452 at least by their higher bit rate compared to the conventional signals CAN_H and CAN_L.

[0088] Figure 5 the sequence of the conditions 401, 402 of signals CAN_H, CAN_L in and the resulting Figure 6 The curve (Verlauf) of the voltage VDIFF in is only used to illustrate the function of the user station 10. The sequence of the data conditions for bus conditions 401, 402 can be selected as required.

[0089] As Figure 3 shown, Figure 3 the receiving module 122 forms a digital received signal RXD ( Figure 7 ) based on signals CAN_H and CAN_L etc. or VDIFF received from bus 40 and passes it to the communication control device 11.

[0090] 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 bus 40. In other words, for Figure 7 the received signal RXD at Figure 3 the connection of the communication control device 11, no signal is received or there is a logical 1 value because the recessive level on bus 40 corresponds to a bit value = 1 or logical 1 in the received signal RXD.

[0091] Below, reference is also made to Figure 8 and Figure 9 to describe the operating mode of the transmission waiting device 15 that is different from the current communication standards for classical CAN, for CAN FD, and for CANXL. The modules and / or blocks of this device 15 can be implemented in hardware and / or software.

[0092] In Figure 3In 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 may evaluate whether the received message 1512A is stored in the received message buffer 1512. If the transmission message 1511A is ready for transmission, 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 the data or the transmission message 1511A to the communication control device 11 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 or the transmission message 1511A as the signal TXD to the CAN bus 40 according to the frame 450.

[0093] 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 status or condition on the bus 40. The (multiple) status information ST_A includes at least one event to which the pause module 152 reacts. 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 configuration parameter 1521A is stored and / or the counting mechanism 1522.

[0094] 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 as the transmission delay signal TX_E hereinafter. Alternatively, the signal TX_E may be referred to as the transmission release signal TX_E.

[0095] For example, TX_E = 0 means that: starting to send signal T_D or frame 450 corresponding to transmission message 1511A is not allowed. In this example, the logical value 1 of signal TX_E, or rather TX_E = 1, thus means that: starting to send frame 450 based on signal T_D corresponding to transmission message 1511A is allowed. If starting to send frame 450 is not allowed based on signal T_D corresponding to transmission message 1511A, pause module 152 delays providing transmission message 1511A for communication control device 11. If starting to send frame 450 or signal T_D is allowed according to this transmission message 1511A, pause module 152 does not delay providing transmission message 1511A for communication control device 11. In other words, pause module 152 releases: providing transmission message 1511A for communication control device 11 or for transmission / reception device 12 to be sent onto bus 40.

[0096] Logic module 153 logically operates signal TX_E with digital signal TX_R and outputs digital signal TX_S.

[0097] Only when transmission waiting device 15 has determined that it is allowed to send transmission message 1511A onto bus 40, will it output corresponding signal TX_S to communication control device 11. In the above example for signal TX_E and logic module 153, if starting to send frame 450 or signal T_D corresponding to transmission message 1511A is allowed, transmission waiting device 15, especially its logic module 153, outputs signal TX_S = 1 to communication control device 11.

[0098] Pause module 152 has counting mechanism 1522, and uses this counting mechanism 1522 to count events, as described below. To determine these events, pause module 152, especially its evaluation block 1523, evaluates status information ST_A sent by communication control device 11.

[0099] Pause module 152 especially uses two types 1521B of events in status information ST_A to count with counting mechanism 1522. Optionally, it is possible to configure which at least one type 1521B of the at least one event is to be counted with type 1521B stored as a configuration parameter in configuration buffer 1521. The two types 1521B of events in status information ST_A can be event E1 and event E2, as shown in the example in Figure 8 as an example.

[0100] Event E1 means that an idle bit "i" is seen. This means that: user station 10, especially its communication control device 11, sees bus 40 in an "idle" condition, or rather in a free-running or standby condition, for one bit.

[0101] Event E2 means that frame reception has started. This means that: user station 10, in particular its communication control device 11, has started receiving frame 450. In the CAN standard, this condition or state of user station 10 is referred to as the receiver. Each start of reception is counted, even if the frame is not successfully received, for example because a reception error has been detected in frame 450 during reception. Optionally, only each successful reception can be counted instead of counting the start of reception.

[0102] The pause module 152 does not distinguish whether only event E1 occurs, only event E2 occurs, or any mixture of events E1 and E2 occurs.

[0103] Furthermore, when seeing the total number of TX_Pause (pause) events E1 and E2 configured with configuration parameter 1521A, the pause module 152 sets signal TX_E accordingly. In this example, configuration parameter 1521A has the value N, which is an integer greater than or equal to 0.

[0104] Expressed mathematically, if the following conditions apply, signal TX_E is set to, in particular, 1 so as not to (any longer) delay the transfer of transmit message 1511A to device 11:

[0105] Configuration parameter 1521A == TX_Pause_Cnt == x + y,

[0106] where x is the number of counted events E1 and y is the number of counted events E2.

[0107] Depending on the implementation, the value of signal TX_E can either be set to TX_E = 0 immediately after starting user station 10 or be set to TX_E = 1 immediately. Both possibilities are practical and feasible.

[0108] If one of the following events E3 to E5 occurs, the pause module 152 resets signal TX_E, in particular to 0, so as to delay the transfer of transmit message 1511A to device 11 or to transfer it to transmit / receive device 12 in frame 450. This can be implementation-specific or configurable for the user using at least one optional type or parameter 1521B with respect to 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. Furthermore, if one of the following events E3 to E5 occurs, the pause module 152 resets the count value 1522A.

[0109] Event E3: The user station 10 has successfully sent frame 450, or in other words, sent message 1511A, to other user stations 20, 30 of the bus system 1. This means that the sending user station 10 has received a reception confirmation in the ACK area (at least one bit) set for this purpose in frame 450 from at least one receiving station. That is, the entire frame 450 has been successfully sent.

[0110] Event E4: The user station 10 has recognized an error during transmission and aborted the transmission of the frame, or the user station 10 has seen an ACK error, which means that the user station 10 has not received a "no error" reception confirmation in the ACK area (at least one bit) set for this purpose from these receiving stations.

[0111] Event E5: The user station 10 has started to send frame 450 to the bus 40 based on the sending message 1511A.

[0112] In particular, only events E3 and E4 are used. This combination results in: The user station 10 can retry sending frame 450 countless times after the user station 10 has lost arbitration. This is desirable and thus advantageous because the user stations 10, 20, 30 on the bus 40 do not have a fixed transmission order, so arbitration occurs regularly.

[0113] Depending on the value of the configuration parameter 1521A, and thus depending on the configuration of the sending waiting device 15 or the pause module 152, the user station 10 has one of the following three operating modes.

[0114] Operating mode B1 corresponds to 100% arbitration. In this case, the behavior of the user station 10 is similar to that of a common CAN user station according to the previously mentioned ISO standard.

[0115] Operating mode B2 corresponds to a certain degree of determinism and a certain degree of arbitration. In this case, at least the behavior of the user station 10 is only partially similar to that of a common CAN user station according to the previously mentioned ISO standard.

[0116] Operating mode B3: For each user station 10, 20, 30 in the bus system 1, there is 100% deterministic bus access. In this case, each user station 10, in addition to having the functions of a common CAN user station according to the previously mentioned ISO standard, also has the functions described above.

[0117] Figure 8 and Figure 9 The previously described working method of the user station 10 in the bus system 1 over time t is illustrated in more detail for a specific example. The following settings apply to this example:

[0118] A) At Figure 1Configure the parameter 1521A (TX_Pause) = 2 in all three user stations 10, 20, and 30.

[0119] B) In Figure 1 In all three user stations 10, 20, and 30, when event E3 or event E4 occurs, the signal TX_E is reset.

[0120] C) User station 10 wants to send three frames or send message 1511A onto the bus 40 after starting.

[0121] D) User stations 20 and 30 only send sporadically.

[0122] Figure 8 Visualizes the situation or state Z_40 on the bus 40 over time t for a specific example. As described above, the pause module 152 forms Figure 9 the signal TX_E according to the state Z_40. For clarity, Figure 8 only the view of user station 10 is shown in

[0123] and will be described in more detail below. Since the method works decentralized, the views of user stations 20 and 30 and the signal TX_E they generate follow accordingly.

[0123] In Figure 8 a specific example of Figure 1 user stations 10, 20, and 30 ( Figure 8 ) are initially switched on and ready to run at the time point T0 in

[0124] Now, all user stations 10, 20, and 30 ( Figure 1 ) start waiting for an event of type E1 or E2 in order to be able to set the signal TX_E as described previously.

[0125] User station 10 sets the signal TX_E to 1 after two idle bits (i.e., after two events E1), as Figure 9 shown. Since the signal is TX_E = 1, user station 10 starts sending (event E5). However, as described below, user station 10 loses arbitration twice. First, in arbitration A123, all user stations 10, 20, and 30 participate in the arbitration, where user station 30 is allowed to send its frame 450 or send message 1511A, as Figure 8 shown as A123, TX3 in Figure 8 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 8 shown as A12, TX2 in

[0126] At time point T1, i.e., after successful transmission (event E3), the user station 10 sets the signal TX_E to 0 again, as Figure 9 shown.

[0127] After two idle bits (i.e., after two events E1 after time point T1), the user station 10 sets the signal TX_E to 1 again, as Figure 9 shown.

[0128] Only the user station 10 participates in the subsequent arbitration A1. Therefore, the user station 10 can successfully transmit its second frame 450 or send the message 1511A, as Figure 8 shown as A1, TX1 in.

[0129] At time point T2, i.e., after successful transmission (event E3), the user station 10 sets the signal TX_E to 0 again, as Figure 9 shown.

[0130] The user station 10 sets the signal TX_E to 1 again after starting to receive the frame 450 or send the message 1511A (event E2) and after an idle bit (event E1), as Figure 9 shown.

[0131] Then, the user station 10 can successfully transmit its third frame 450 or send the message 1511A, as Figure 8 shown as A1, TX1 in.

[0132] At time point T3, i.e., after successful transmission (event E3), the user station 10 sets the signal TX_E to 0 again, as Figure 9 shown.

[0133] Therefore, the design of the user station 10 provides a very low-cost and uncomplicated configuration of the user station 10 and an implementation of the method executed by it in the bus system 1. This also applies to the other user stations 20, 30. The reason is that in the CAN bus system, only one scalar parameter, i.e., the configuration parameter 1521A, is used for each user station 10, 20, 30. This means that the system designer can use only one configuration parameter 1521A for each CAN user station 10, 20, 30 to set the behavior on the bus 40 to one of the three different operating modes B1, B2, B3 mentioned above. Here, a smooth transition between the operating modes B1, B2, B3 is possible, as described above and below.

[0134] For example, the configuration parameters 1521A of the user stations 10, 20, 30 are set as follows.

[0135] Example 1

[0136] The configuration parameter 1521A of user station 10 is set to 0.

[0137] The configuration parameter 1521A of user station 20 is set to 0.

[0138] The configuration parameter 1521A of user station 30 is set to 0.

[0139] In the case of such a configuration, there is no restriction on the sending behavior. Each of user stations 10, 20, and 30 has specified its behavior as in the international standard ISO11898-1:2015 for CAN FD or subsequent standards for CAN XL. Therefore, each of user stations 10, 20, and 30 behaves in the same way as a user of a bus system is accustomed to from a CAN node or user station.

[0140] Example 2

[0141] The configuration parameter 1521A of user station 10 is set to 2.

[0142] The configuration parameter 1521A of user station 20 is set to 2.

[0143] The configuration parameter 1521A of user station 30 is set to 2.

[0144] In the case of such a configuration, user stations 10, 20, and 30 equally share the bus bandwidth. Each of user stations 10, 20, and 30 obtains 1 / 3 of the bus bandwidth or frame rate. This is 100% deterministic bus access because each of user stations 10, 20, and 30 can send a frame 450 or send a message 1511A at the latest after two received frames 450 or sent messages 1511A.

[0145] Example 3

[0146] The configuration parameter 1521A of user station 10 is set to 9.

[0147] The configuration parameter 1521A of user station 20 is set to 9.

[0148] The configuration parameter 1521A of user station 30 is set to 9.

[0149] In the case of such a configuration, the same content as in Example 2 applies. Additionally, there may be a possibility to add 7 additional user stations 10, 20, and 30 to the bus 40 without having to change the configuration of the user stations 10, 20, and 30 already connected to the bus 40. If 10 user stations 10, 20, and 30 are connected to the bus 40, each of the 10 user stations obtains 1 / 10 of the bus bandwidth or frame rate. Therefore, 100% deterministic bus access also applies to Example 3.

[0150] Example 4

[0151] Configuration parameter 1521A is set differently for user stations 10, 20, 30. In this case, configuration parameter 1521A has a different value for at least one user station than for at least one other user station on bus 40. That is, configuration parameter 1521A does not have to have the same value for all user stations 10, 20, 30 on bus 40. In this way, a larger bandwidth or frame rate can be assigned to at least one user station than to at least one other user station 10, 20, 30 on bus 40.

[0152] Of course, instead of ten user stations, more or fewer user stations can be connected to bus 40. In this case, the configuration parameters 1521A of the user stations are set accordingly, as described in Example 3.

[0153] According to the second embodiment, the transmission waiting device 15 of at least one user station 10 of bus system 1 is designed to sequentially transmit up to N frames 450 before the device 15 sets its signal TX_E = 0. N is a configurable parameter. N is a natural number greater than or equal to 1.

[0154] As long as the signal TX_E = 1 is set, one of the user stations 10, 20, 30 can transmit up to N frames 450, especially one after another. This means that the device 15 only sets its signal to TX_E = 0 after N messages have been sent. A reasonable value range for N is from 1 to 10, because this also creates or increases the opportunity for other user stations in bus system 1 to transmit frame 450.

[0155] 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 bus system 1.

[0156] According to the third embodiment, the transmission waiting device 15 of at least one user station 10 of bus system 1 is designed to successively transmit up to N bytes of useful data before the device 15 sets its signal to TX_E = 0. N is a configurable parameter. N is a natural number greater than or equal to 1.

[0157] All of the previously described design options for user stations 10, 20, 30, bus system 1, and the methods performed therein can be used individually or in all possible combinations. In particular, all 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.

[0158] Although the invention has been described above by way of example of a CAN bus system, the invention can be applied in every communication network and / or communication method in which two different communication phases are used, in which the bus conditions arising for the different communication phases are different.

[0159] 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. An advantageous but not necessary prerequisite is that in the bus system 1, exclusive and collision-free access to the common channel by the user stations 10, 20, 30 is ensured at least for a specific period of time.

[0160] 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 user stations in the bus system 1 are designed to be the same, i.e., 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), 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 sending waiting device (15), wherein the message sending waiting device comprises a pause module (152), and / or The pause module (152) is further designed to determine whether to delay or not to delay: sending the send message (1511A) onto the bus (40).

4. A user station (10; 20; 30) according to any one of the preceding claims, wherein The user station also has: 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).

5. 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).

6. 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 status information (ST_A) related to at least one event (E1; E2; E3; E4; E5) on the bus (40) and a configuration parameter (1521A).

7. A user station (10; 20; 30) according to claim 6, wherein the pause module (152) has a configuration buffer for storing configuration parameters (1521A) that are selectable for the user station (10; 20; 30) as needed, and optionally for storing configuration parameters describing at least one type (1521B) of the at least one event (E1; E2; E3; E4; E5).

8. The user station (10; 20; 30) according to claim 6 or 7, in, 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).

9. The user station (10; 20; 30) according to any one of claims 6 to 8, 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).

10. The user station (10; 20; 30) according to any one of claims 5 to 9, wherein: At least one event (E3) on the bus (40) includes: the communication control device (11; 21; 31) has successfully sent a signal (TXD; CAN_H, CAN_L) corresponding to the frame (450) to the bus (40).

11. The user station (30) according to any one of claims 5 to 10, 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).

12. The user station (10; 20; 30) according to any one of claims 5 to 11, wherein at least one event (E5) on the bus (40) comprises: The communication control device (11; 21; 31) has started to transmit a signal (TXD; CAN_H, CAN_L) has been successfully sent to the bus (40).

13. The user station (10; 20; 30) according to any one of claims 5 to 9, The user station further comprises a counting device (1522) for counting the at least one event (E1; E2), The counting mechanism (1522) is designed to count all events (E1; E2) occurring in the at least one state information (ST_A) output by the communication control device (11; 21; 31), and If the number of events (E1; E2) counted by the counting mechanism (1522) is equal to the configuration parameter (1521A), the pause module (152) changes the value of the transmission delay signal (TX_E) so as not to delay providing the transmission message (1511A) to the communication control device (11; 21; 31).

14. The user station (10; 20; 30) according to claim 13, wherein the pause module (152) is designed to increase the count value (1522A) of the counting mechanism (1522) after an event (E1; E2) is detected according to any one of claims 7 to 9, and The pause module (152) is designed to reset the count value (1522A) of the counting mechanism (1522) after detecting an event (E3; E4; E5) according to any one of claims 10 to 12, and to change the value of the sending delay signal (TX_E) so as to delay providing a sending message (1511A) for the communication control device (11; 21; 31).

15. A subscriber station (10; 20; 30), further comprising a transmitting / receiving device (12; 32) connected to a bus (40) and designed to generate a digital reception 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).

16. A bus system (1), the bus system having a bus (40), and At least two subscriber stations (10; 20; 30) according to any one of the preceding claims, wherein the at least two subscriber stations are connected to one another via the bus (40) in such a way that the subscriber stations (10; 20; 30; 50) can communicate with one another serially.

17. 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); The method comprises: receiving a message (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: evaluating, by means of the pause module (152), at least one piece of status information (ST_A) outputted from the communication control device (11; 21; 31), 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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