Transceiver device for a subscriber station of a serial bus system, and method for a communication using differential signals in a serial bus system

Abstract

The invention relates to a transceiver device (12) for a subscriber station (10; 30) of a serial bus system (1; 1A) and to a method for communication in a serial bus system (1; 1A). The transceiver device has a transmitting module (121) for transmitting a digital transmission signal (TxD; Tx) as a differential analog signal (CAN_H, CAN_L; LINE+, LINE-) to a bus (40; 40A) of the bus system (1; 1A) in order to transmit a message (45; 48) to at least one other subscriber station (10; 20; 30) of the bus system (1; 1A); a receiving module (122) for receiving signals (CAN_H, CAN_L; LINE+, LINE-) from the bus (40; 40A) and for generating a received digital signal (RxD; Rx) from the differential analog signal (CAN_H, CAN_L; LINE+, LINE-); a first connection (TXD / TX) for receiving the transmission signal (TxD; Tx) from a communication control device (11; 11A); a second connection (RXD / RX) for outputting the received digital signal (RxD; Rx) to the communication control device (11; 11A); a third connection (STB / ED) which can be switched so as to function as a digital output or a digital input; and a COM-IF determination module (125) for evaluating whether the third connection (STB / ED) is switched so as to function as an output or as an input if the transceiver device (12) is switched to an operating mode in which the transceiver device (12) can actively communicate via at least one of the first to third connections (TXD / TX; RXD / RX; STB / ED), said transmitting module (121) and receiving module (122) each having a configuration for two different communication standards (CAN; 10 BASE-T1S) and being settable for a communication in the serial bus system (1; 1A) in accordance with one of the two communication standards (CAN; 10 BASE-T1S) on the basis of the evaluation result of the COM-IF determination module (125).

Description

[0001] Description

[0002] Transmitting / receiving device for a subscriber station of a serial bus system and method for communication with differential signals in a serial bus system

[0003] The present invention relates to a transmitting / receiving device for a subscriber station of a serial bus system and a method for communication with differential signals in a serial bus system.

[0004] State of the art

[0005] Serial bus systems have a bus to which participating devices are connected via a transceiver to communicate with each other. During communication, data is exchanged between the participating devices, which can be, for example, sensors, control units in a vehicle or a production plant, etc. Various standards or data transmission protocols exist for data transmission in serial bus systems. Well-known standards for serial bus systems with differential signals include CAN XL, 10BASE-T1 S-Ethernet, FlexRay, LVDS (Low Voltage Differential Signaling), and others.

[0006] Each of these serial bus systems uses differential signals with different signal states, which serially signal the data to be exchanged.

[0007] It is possible that one part of the technical system uses a bus system with a different communication standard than another part. For example, a CAN bus system might be used for communication in a vehicle's emergency braking system, whereas a 10BASE-T1 S-bus system might be used for communication in a windshield wiper system.

[0008] The problem is that communication in the CAN bus system and communication in the 10BASE-T1 S-bus system are not compatible. For example, if at least one control unit needs to be replaced due to a defect, a replacement control unit that supports the communication standard of the bus system to which the replaced control unit was connected is not always available in time.

[0009] In addition, the data from some of the vehicle's devices, such as a rain sensor or a warning signal generator, etc., are needed for parts of the technical system that communicate using different communication standards.

[0010] To solve this problem, two devices, in particular two rain sensors and / or warning signal generators, etc., could be used, one of which is connected to the CAN bus system and the other to the 10BASE-T1 S-bus system.

[0011] Alternatively, such a device may have communication devices designed for communication in the CAN bus system and communication devices designed for communication in the 10BASE-T1 S-bus system.

[0012] However, this requires significantly more equipment than a system that uses only one communication standard. Consequently, the system requires more space and is considerably more expensive to manufacture and maintain.

[0013] Disclosure of the invention

[0014] Therefore, the object of the present invention is to provide a transmit / receive device for a subscriber station of a serial bus system and a method for communication with differential signals in a serial bus system, which solve the aforementioned problems. In particular, a transmit / receive device for a subscriber station of a serial bus system and a method for communication with differential signals in a serial bus system are to be provided that solve the compatibility problem between different communication standards in a technical system.

[0015] The problem is solved by a transmit / receive device for a subscriber station of a serial bus system with the features of claim 1. The transmit / receive device has a transmit module for sending a digital transmit signal as an analog differential signal to a bus of the bus system in order to send a message to at least one other subscriber station of the bus system, a receive module for receiving signals from the bus and for generating a digital receive signal from the analog differential signal, a first connection for receiving the transmit signal from a communication control unit, a second connection for outputting the digital receive signal to the communication control unit, a third connection which can be switched as a digital output or input, and a COM-IF determination module for evaluation if the transmit / receive device is switched to an operating mode.in which the transmitting / receiving device can actively perform communication via at least one of the first to third connections, whether the third connection is configured as an output or as an input, wherein the transmitting module and the receiving module each have a configuration for two different communication standards and are configurable for communication in the serial bus system according to one of the two communication standards based on the evaluation result of the COM-IF determination module.

[0016] The described transceiver has, in addition to a first connection for a digital transmit signal and a second connection for a digital receive signal, a third connection for a digital signal. Using a special module at this third connection, the described transceiver can detect whether the combined transceiver should behave according to the 10BASE-T1 S standard or the CAN-XL standard, without requiring an additional connection or non-standard inputs from the communication control unit, particularly its controller. The module is designed to detect the input level and / or impedance at the third connection.

[0017] Thus, the described transmitter / receiver can independently detect which communication standard a connected communication control unit uses. This allows for a very high degree of flexibility in selecting the communication standard for the bus system and therefore the communication control unit, provided the described transmitter / receiver is connected to the bus in its original configuration.

[0018] An additional advantage is that electrical circuit components, such as the power supply, etc., of the described transceiver can be used for two different communication standards. As a result, the described transceiver can save semiconductor space. This optimizes the space requirements of the transceiver and the bus system. Consequently, the described transceiver is extremely resource-efficient and cost-effective.

[0019] Due to the design of the described transceiver, the effort required to adapt the communication control unit to the transceiver is very low. Only the wiring of the connections (pins) for the bus lines needs to be adapted to the communication control unit being used.

[0020] Furthermore, due to the design of the described transmitting / receiving device, reliable communication with a very low error rate is nevertheless enabled in an uncomplicated and cost-effective manner for at least two different differential bus systems.

[0021] The described transceiver enables a relatively simple change in the communication standard for an existing wiring setup. This is because the described transceiver can be used with minimal configuration effort for bus systems that support communication using different communication standards. If necessary, this also allows an existing device in a technical system, particularly a vehicle, to be flexibly connected to different bus systems that support communication using different communication standards, as required.

[0022] The described transmit / receive device is designed to be configured as a CAN SIC transmit / receive device and / or CAN XL transmit / receive device and / or 10BASE-T1 S transmit / receive device, depending on the connected communication control device.

[0023] Overall, the described transmitting / receiving device can not only realize communication in the bus system between other subscriber stations with the (high) bit rates required for the respective communication standard, but is also designed in such a way that the transmissible bit rate is not reduced by errors in the communication.

[0024] The described transceiver can be used particularly for gateway products. Such gateway products typically include a power supply unit and several interfaces. For example, a voltage supply U_bat is regulated to 5V to operate multiple CAN transceivers and / or LIN transceivers. Such a gateway can contain several identical transceivers as described above, which can then be operated by Tierl as transceivers for CAN-XL (CAN-SIC) or 10BASE-T1 S via the controller.

[0025] Advantageous further embodiments of the transmitting / receiving device are described in the dependent claims. The COM-IF determination module can include a comparator and resistors to detect the voltage level and / or impedance at the third terminal. The comparator can be connected between two series circuits of resistors, with the two series circuits connected in parallel.

[0026] According to one embodiment, the COM-IF determination module, if the transmitting / receiving device is switched to the operating mode in which the transmitting / receiving device can actively perform communication via at least one of the first to third connections, and if the third connection is configured as an input, is designed to additionally evaluate whether a predetermined property of one of the two communication standards has been executed or not.

[0027] In this case, the transmitting / receiving device can be switched to the CONFIG operating mode, in which the transmitting / receiving device can actively perform communication via the third port, where the predetermined property of the communication standard of the two communication standards is state handling according to 10BASE-T1 S.

[0028] The previously described transmit / receive device may also have a COM-IF acquisition module for evaluating the digital transmit signal at the first port in order to configure the transmit module and the receive module for communication in the serial bus system according to one of the two communication standards.

[0029] It is also conceivable that the previously described transmit / receive device includes an operating mode selection module for choosing an operating mode for the transmit module and / or the receive module based on an evaluation result from the COM-IF determination module. In this case, the operating mode selection module could be designed to also evaluate the transmit signal at the first terminal to select the operating mode of the transmit module and / or the receive module. Additionally or alternatively, it is possible that, after forwarding an evaluation result to the operating mode selection module, the COM-IF determination module could further evaluate whether the third terminal is configured as an output or an input.

[0030] In one embodiment, the transmitting module is designed to generate the analog differential signals in a first communication phase of the message with a different physical layer than in a second communication phase, when using one of the two communication standards.

[0031] The two communication standards CAN XL and 10BASE-T1 S are optional.

[0032] The previously described transmit / receive device can be part of a subscriber station for a serial bus system. The subscriber station can also be a communication control device for managing communication within the bus system and generating the transmit signal. The subscriber station can be configured for communication within the bus system in such a way that, at least temporarily, exclusive, collision-free access to the bus of a subscriber station is guaranteed.

[0033] At least two of the previously described transmit / receive devices can be part of a gateway for forwarding messages between at least a first bus system and a second bus system, wherein one of the at least two transmit / receive devices of the gateway is connected to the first bus system and another of the at least two transmit / receive devices is connected to the second bus system.

[0034] The aforementioned problem is further solved by a method for communication with differential signals in a serial bus system with the features of claim 15. The method is implemented with a transmit / receive device for a participant station of the bus system, which comprises a transmit module, a receive module, a first terminal, a second terminal, a third terminal which is switchable as a digital output or input, and a COM-IF determination module, wherein the transmit module and the receive module each have an configuration for two different communication standards, and wherein the method comprises the steps of receiving, at the first terminal, a digital transmit signal from a communication control device, wherein the transmit signal is configured for transmission as an analog differential signal to a bus of the bus system in order to send a message to at least one other participant station of the bus system, evaluating,with the COM-IF determination module, if the transmit / receive device is switched to an operating mode in which the transmit / receive device can actively perform communication via at least one of the first to third ports, whether the third port is configured as an output or as an input, switching the transmit module and the receive module based on the evaluation of the COM-IF determination module for communication in the serial bus system according to one of the two communication standards, transmitting, with the transmit module, the transmit signal as an analog differential signal onto the bus according to the set communication standard, and / or receiving, with the receive module, analog differential signals from the bus to output a digital receive signal according to the set communication standard to the communication control unit.

[0035] The method offers the same advantages as previously mentioned in relation to the transmitting / receiving equipment.

[0036] Furthermore, the described transmit / receive device also performs a method for setting the transmit / receive device to one of two communication standards for communication with differential signals in a serial bus system in the procedure for communication with differential signals in a serial bus system.

[0037] Other possible implementations of the invention also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In such cases, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0038] Drawings The invention is described in more detail below with reference to the accompanying drawing and by means of exemplary embodiments. The drawings show:

[0039] Fig. 1 shows a simplified block diagram of a gateway with bus systems according to a first embodiment;

[0040] Fig. 2 is a diagram illustrating the structure of a frame for a message that can be sent by a subscriber station of a bus system according to the first embodiment;

[0041] Fig. 3 shows a block diagram of a transmit / receive device of a subscriber station of the bus system of Fig. 1;

[0042] Fig. 4 shows a block diagram of the transmit / receive device of Fig. 3 when the transmit / receive device is set for a first communication standard for differential signals on the bus with frame according to Fig. 2;

[0043] Fig. 5 shows an electrical circuit of a communication interface determination module of the transmitting / receiving device of Fig. 3, which is connected to a switching module of a communication control device for the first communication standard;

[0044] Fig. 6 shows a block diagram of the transmit / receive device of Fig. 3 when the transmit / receive device is set for a second communication standard for differential signals on the bus;

[0045] Fig. 7 shows the electrical circuit of a communication interface determination module of the transmitting / receiving device of Fig. 3, which is connected to a switching module of the communication control device for the second communication standard;

[0046] Figures 8 to 11 show an example of the time course of signals received by the transmit / receive device in the configuration of Figure 4 for a frame of Figure 2 or generated on the bus; Figure 12 shows another example of the time course of signals received by the transmit / receive device in the configuration of Figure 4 during an arbitration phase (SIC operating mode);

[0047] Fig. 13 shows the time course of the bus signals CAN_H, CAN_L, which are sent to the bus by the transmit / receive device of Fig. 4 based on the transmit signal of Fig. 12; and

[0048] Figs. 14 to 17 show an example of a time course of signals received by the transmit / receive device in the configuration of Fig. 8 or generated on the bus.

[0049] In the figures, identical or functionally equivalent elements are provided with the same reference symbols unless otherwise specified.

[0050] Description of the exemplary implementations

[0051] Fig. 1 shows a first bus system 1 and a second bus system 1A, which are connected to each other via a gateway 5. However, the gateway 5 can be connected to more than two bus systems 1 and 1A, although this is not shown in the figures.

[0052] The first bus system 1 can, for example, be at least partially a CAN bus system, such as a Classical CAN bus system, a CAN FD bus system, a CAN XL bus system, etc., according to the international standard ISO 11898-1:2024. The second bus system 1A can, for example, be at least partially a 10BASE-T1 S bus system according to the international standard IEEE 802.3cg™. However, the bus systems 1 and 1A are not limited to this. In particular, the bus systems 1 and 1A can be configured to operate according to the same communication standard. The bus systems 1 and 1A can be used in a vehicle, especially a motor vehicle, an aircraft, etc., or in a hospital, etc.Although the bus systems 1 , 1 A are described below using CAN bus systems and 10BASE-T1 S-bus systems, none of the bus systems 1 , 1 A are limited to this. Alternatively, at least one of the bus systems 1 , 1 A can be another serial bus system 1 that uses differential signals in particular.

[0053] In Fig. 1, the bus system 1 has a plurality of participant stations 10, 20, 30, which, like the gateway 5, are each connected to a bus 40 or bus line with a first bus wire 41 and a second bus wire 42. In a CAN bus system, the bus wires 41 and 42 can also be called CANH and CANL for carrying signals CAN_H and CAN_L on the bus 40. The bus wires 41 and 42 together form the bus line for the bus 40.

[0054] In the example shown in Fig. 1, bus system 1A has a subscriber station 50, which, like gateway 5, is connected to a bus 40A or bus line with a first bus wire 41A and a second bus wire 42A. In a 10BASE-T1 S-bus system 1A, the bus wires 41A and 42B are called LINE+ and LINE-, respectively. The bus wires 41A and 42B together form the bus line for bus 40A.

[0055] Messages 45, 46, and 47, in the form of signals, can be transmitted via the first bus 40 between the individual participant stations 10, 20, and 30 and the gateway 5. Messages 48, in the form of signals, can be transmitted via the second bus 40A between participant station 50 and the gateway 5. The gateway 5 can convert messages 45, 46, and 47 into the required communication standard and forward them to bus 40A, and / or forward a message 48 to bus 40. The participant stations 10, 20, 30, and 50 are, for example, control units or display devices of a motor vehicle.

[0056] As shown in Fig. 1, the subscriber stations 10, 30 each have a communication control unit 11 and a transmit / receive unit 12. The transmit / receive unit 12 has a transmit module 121 and a receive module 122. The subscriber station 20 has a communication control unit 21 and a transmit / receive unit 22. The transmit / receive unit 22 has a transmit module 221 and a receive module 222.

[0057] The subscriber station 50 has a communication control unit 11 A and a transmit / receive unit 12. The transmit / receive unit 12 also has a transmit module 121 and a receive module 122, although this is not shown in Fig. 1.

[0058] The transmit / receive equipment 12 of subscriber stations 10 and 30, and the transmit / receive equipment 22 of subscriber station 20, are each directly connected to bus 40, even though this is not shown in Fig. 1. The same applies to the transmit / receive equipment 12 of subscriber station 50 with respect to bus 40A.

[0059] The communication control units 11 and 21 each serve to control communication between the respective subscriber stations 10, 20, and 30 via bus 40 and at least one other subscriber station of subscriber stations 10, 20, and 30 that is connected to bus 40. The same applies to the communication control unit 11A of subscriber station 50 with respect to bus 40A.

[0060] The communication control unit 11 creates and reads initial messages 45 and 47, which are, for example, modified CAN messages 45 and 47. These modified CAN messages 45 and 47 are based, for example, on the CAN XL format. The transmit / receive unit 12 is used to send and receive messages 45 and 47 from bus 40. The transmit module 121 receives a digital transmit signal TxD generated by the communication control unit 11 for one of the messages 45 and 47 and converts it into signals for transmission on bus 40. The digital transmit signal TxD can be a pulse-width modulated signal, at least temporarily or in sections. The receive module 122 receives signals transmitted on bus 40 corresponding to messages 45 to 47 and generates a digital receive signal RxD from them. The receiver module 122 sends the receive signal RxD to the communication control unit 11.Additionally, the communication control unit 11 can be configured to create and read second messages 46, which are, for example, CAN FD messages 46. The transmit / receive unit 12 can be configured accordingly.

[0061] The communication control unit 11 A is described in more detail with reference to Figs. 3 to 7.

[0062] The communication control unit 21 of Fig. 1 can be implemented like a conventional CAN controller according to ISO 11898-1:2015, i.e., like a CAN FD-tolerant Classical CAN controller or a CAN FD controller. The communication control unit 21 creates and reads secondary messages 46, for example, CAN FD messages or Classical CAN messages. The transmit / receive unit 22 is used to send and receive the messages 46 from the bus 40. The transmit module 221 receives a digital transmit signal TxD created by the communication control unit 21 and converts it into signals for a message 46 on the bus 40. The receive module 222 receives signals transmitted on the bus 40 corresponding to messages 45 to 47 and generates a digital receive signal RxD from them. The transmit / receive unit 22 may be implemented like a conventional CAN FD transceiver or CAN SIC transceiver.

[0063] To send messages 45, 46, 47 to bus 40 using CAN SIC or CAN XL, proven features are adopted that contribute to the robustness and user-friendliness of CAN and CAN FD, in particular the frame structure with identifier and arbitration according to the well-known CSMA / CR method. The CSMA / CR method necessitates the existence of so-called recessive states on bus 40, which can be overwritten by other participating stations 10, 20, 30 with dominant levels or dominant states on bus 40.

[0064] With the two participant stations 10, 30, the formation and subsequent transmission of messages 45, 47 using various CAN formats, in particular the Classical CAN format, the CAN FD format, or the CAN XL format, as well as the reception of such messages 45, 47, is possible. This is described in more detail below for message 45.

[0065] If no communication takes place on bus 40, at least one of the participant stations 10, 20, 30, in particular their communication control unit 11, 21, can be put into a sleep mode. This saves energy.

[0066] In CAN XL, the subscriber station 10, 30 switches its transmit / receive device 12 to a SLOW or SIC operating mode in order to participate in communication on the bus 40. In SLOW or SIC operating mode, the subscriber station 10, 30 can participate in an arbitration between the subscriber stations 10, 20, 30 of the bus system 1 during an arbitration phase 451 (first communication phase) of a frame from Fig. 2.

[0067] Fig. 2 shows a frame 450 for message 45, which is in particular a CAN XL frame, as provided by the communication control unit 11 to the transmit / receive unit 12 for transmission on bus 40. In this embodiment, the communication control unit 11 creates the frame 450 as compatible with CAN FD. Alternatively, the frame 450 is compatible with any successor standard for CAN FD. The frame 450 has a maximum duration T_450, which corresponds to a predetermined maximum frame length.

[0068] According to Fig. 2, the frame 450 for CAN communication on bus 40 is divided into different communication phases 451 and 452, namely an arbitration phase 451 (first communication phase) and a data phase 452 (second communication phase). Following a start bit SOF, the frame 450 has an arbitration field 453, a control field 454, a first changeover field 455, a data field 456, a checksum field 457, a second changeover field 458, and a frame termination field 459. The checksum field 457 and the second changeover field

[0069] 458 and the frame closing field 459 form a frame end phase 457, 458,

[0070] 459 of frame 450. In the arbitration phase 451, using an identifier (ID) in the arbitration field 453, the participating stations 10, 20, 30 negotiate bitwise which station wants to send the message 45, 46 with the highest priority and therefore receives exclusive access to bus 40 of bus system 1 for sending in the subsequent data phase 452. In the arbitration phase 451, a physical layer such as CAN, CAN FD, or CAN SIC is used. The physical layer corresponds to the physical layer or layer 1 of the well-known OSI model (Open Systems Interconnection model).

[0071] During phase 451, the well-known CSMA / CR protocol is used, which allows simultaneous access to bus 40 by participant stations 10, 20, and 30 without destroying the higher-priority message 45 or 46. This makes it relatively easy to add further bus participant stations 10, 20, and 30 to bus system 1, which is very advantageous.

[0072] The CSMA / CR protocol necessitates the existence of recessive states on bus 40, which can be overridden by other participant stations 10, 20, 30 with dominant levels or states on bus 40. In the recessive state, high impedance conditions prevail at individual participant stations 10, 20, 30, which, in combination with the parasitic effects of the bus circuitry, results in longer time constants. This limits the maximum bit rate of today's CAN FD physical layer to approximately 2 megabits per second in real-world vehicle applications.

[0073] At the end of the arbitration phase 451, the first switching field 455 switches to the operating mode for the data phase 452. With CAN-XL, the participating station 10, 30, in particular its transmit / receive unit 12, which won the arbitration and is therefore the sender of the frame 450 in the data phase 452, switches to a FAST_TX operating mode. However, with CAN XL, the participating station 10, 30, in particular its transmit / receive unit 12, which lost the arbitration and is therefore only the receiver of the frame 450 in the data phase, switches to a FAST_RX operating mode. In data phase 452, in addition to part of the first switching field 455, the payload data of the CAN-XL frame 450 or message 45 from data field 456, as well as the checksum field 457 and part of the second switching field 458, are sent. At the end of data phase 452, the second switching field 458 switches back to arbitration phase 451.

[0074] A sender of message 45 only begins sending bits of data phase 452 to bus 40 when the subscriber station 10, as the sender, has won the arbitration and thus has exclusive access to bus 40 of bus system 1 for sending.

[0075] Thus, in the arbitration phase 451, the participating stations 10 and 30 partially use a format known from CAN / CAN-FD according to ISO 11898-1:2015, particularly up to and including the FDF bit. However, compared to CAN or CAN FD in the data phase 452, the second communication phase, an increase in the net data transmission rate to over 10 megabits per second, specifically 20 Mbit / s, is possible. Furthermore, increasing the size of the payload per frame, particularly to approximately 2 kilobytes or any other value, is possible.

[0076] Fig. 3 shows the transceiver 12 in more detail, which can be used for one of the subscriber stations 10, 30. The transceiver 12 has a TXD / TX connection for a transmit signal from Fig. 8 or Fig. 12 or Fig. 14, an RXD / RX connection for a receive signal from Fig. 11 or Fig. 17, an STB / ED connection, in particular for a status signal, a CANH / LINE+ connection for the CAN_H or LINE+ signal, and a CANL / LINE- connection for the CAN_L or LINE- signal. Additionally, the transceiver 12 has connections for a power supply VCC, ground (GND), and VIO for an optional alternative power supply to the TXD / TX, RXD / RX, and STB / ED connections. However, the number of ports on the transmitter / receiver unit 12 is not limited to the stated number of 8 ports. Instead, the number of ports can be selected as needed.The transmit / receive device 12 also includes the transmit module 121, the receive module 122, an operating mode selection module 123, an optional communication interface acquisition module 124, and a communication interface determination module 125. The optional communication interface acquisition module 124 is hereinafter referred to as the COM-IF acquisition module 124. The communication interface determination module 125 is described in more detail with reference to Figures 4 to 7. The communication interface determination module 125 can also be called the COM-IF determination module 125.

[0077] The optional COM-IF acquisition module 124 has a test block 1241 for checking the status of the TXD / TX, STB / ED terminals and / or a signal at the respective TXD / TX, STB / ED terminal. The COM-IF acquisition module 124 also has a decision block 1242 for determining which communication control unit 11, 11A is connected to the transmit / receive unit 12. The COM-IF acquisition module 124 thus performs an evaluation of the status, in particular the voltage level or resistance value, of the TXD / TX, STB / ED terminals and / or a signal at the respective TXD / TX, STB / ED terminal. This is described in more detail below.

[0078] The transmitter module 121 can be configured as a full bridge with four transmission stages, which are not shown in the figures. The transmitter module 121 has an internal resistance of 1211.

[0079] The optional COM-IF acquisition module 124 can be a digital component, specifically a discrete-time system. The COM-IF acquisition module 124 can operate at a predetermined frequency suitable for testing the signal at the TXD / TX connector. Specifically, the frequency is greater than 400 MHz.

[0080] The transmitter / receiver 22 can be constructed in the same way as the transmitter / receiver 12. Therefore, the transmitter / receiver 22 is not described separately. In the transmitter / receiver 12, the voltage supply for the first and second bus wires 41, 42 is provided via the at least one VCC terminal. In particular, a voltage of 5 V or 3.3 V, or any other desired voltage, can be connected to the VCC terminal. The connection to ground, in particular CAN_GND, is implemented via the GND terminal.

[0081] The transceiver 12 can be connected to bus 40 via the CANH / LINE+ and CANL / LINE- connections, specifically its first bus wire 41 for CAN_H or CAN-XL_H or LINE+ and its second bus wire 42 for CAN_L or CAN-XL_L or LINE-. More precisely, the transceiver module 121 is connected at its output to the CANH / LINE+ and CANL / LINE- connections. Furthermore, the receiver module 122 is connected at its input to the CANH / LINE+ and CANL / LINE- connections.

[0082] The transmitter module 121 is connected at its input to the TXD / TX terminal for receiving a transmit signal TxD shown in Fig. 8 or Fig. 12 from the communication control unit 11 of Fig. 1, or for receiving a transmit signal Tx shown in Fig. 14. Furthermore, the transmitter module 121 is connected at its input to an output of the operating mode selection module 123, at which an operating mode selection signal B_SW containing information for selecting the operating mode to be switched is output.

[0083] The receiver module 122 is also connected at its input to the output of the operating mode selection module 123, at which the operating mode switching signal B_SW is output. A first output of the receiver module 122 is connected to the RXD / RX terminal for outputting a receive signal RxD, as shown in Fig. 11, to the communication control unit 11 of Fig. 1, or for outputting a receive signal Rx, as shown in Fig. 17, to a communication control unit. A second output of the receiver module 122 is connected to the STB / ED terminal. The operating mode selection module 123 of Fig. 3 is connected at a first input terminal to the TXD / TX terminal for receiving the transmit signal TxD or Tx, as described above. Furthermore, the operating mode selection module 123 of Fig. 3 is connected at a second input terminal to the output of the optional COM-IF acquisition module 124. Furthermore, the operating mode selection module 123 is shown in Fig.3. The third input port is connected to the STB / ED port. The output port of the operating mode selection module 123 is connected to the transmit module 121 and the receive module 122, as described previously.

[0084] The optional COM-IF acquisition module 124 of Fig. 3 is connected at its first input to the TXD / TX port for receiving the transmit signal TxD or Tx, as described previously. Additionally, the COM-IF acquisition module 124 of Fig. 3 is connected at its second input to the STB / ED port.

[0085] If the COM-IF acquisition module 124 is present, the module 124 evaluates the input at the TXD / TX, STB / ED terminals to determine whether the transmit / receive device 12 is connected to a communication control unit 11 (CAN-XL controller) or a communication control unit 11A (10BASE-T1 S controller) from Fig. 6. The COM-IF acquisition module 124 outputs its evaluation result to the operating mode selection module 123.

[0086] The operating mode selection module 123 is designed to determine the current operating mode from the output of module 125, namely, for example, SLEEP, SLOW or SIC, FAST_TX, FAST_RX for CAN-XL or LOW_POWER, NORMAL, TRANSMITTING, CONFIG for 10BASE-T1 S. Additionally, the operating mode selection module 123 can be configured to determine the current operating mode from the inputs at the TXD / TX connector and the output of the optional module 124, namely, for example, SLEEP, SLOW or SIC, FAST_TX, FAST_RX for CAN XL or LOW_POWER, NORMAL, TRANSMITTING, CONFIG for 10BASE-T1 S.

[0087] Furthermore, the operating mode selection module 123 is designed to

[0088] The result of the determination, i.e., the information about the operating mode, is forwarded to modules 121 and 122 in the signal B_SW. Specifically, the operating mode selection module 123 uses the signal B_SW to switch the operating mode of the transmit module 121 and the operating mode of the receive module 122 according to the required communication standard for which the transmit / receive device 12 is to be used. This is described below with reference to Fig. 4 in relation to a CAN bus system 1 and with reference to Fig. 6 in relation to a 10BASE-T1 S-bus system 1A.

[0089] As explained in more detail below with reference to Fig. 4 to Fig. 7, the RXD / RX connection and the STB / ED connection of the transmit / receive device (transceiver) 12 can be switched differently for use in the bus systems 1 , 1 A.

[0090] The following Table 1 shows an example of the types and functions of the individual connectors (SO8 connector or SO8 pin) of the transmit-

[0091] / Receiving unit 12 of Fig. 3.

[0092]

[0093] Table 1: Comparison of the type and function of the connections of the transmit / receive device 12 for CAN XL and 10BASE-T1 S

[0094] Fig. 4 shows that the transceiver 12 in a CAN bus system 1 is connected between the communication control unit 11 of Fig. 1 and a DC choke 13 for communication according to the CAN XL standard. The DC choke 13 is connected to the bus wires 41, 42 of the bus line for bus 40 via a line connector 15. The DC choke 13 is also called a common-mode choke (CMC). The bus wires 41, 42 can be configured as twisted pairs. The first and second bus wires 41, 42 are terminated with a terminating resistor 49. The terminating resistor 49 is an external load resistor for the transmitter module 121. As mentioned previously, the transmitter module 121 can be configured as a full bridge with four transmitter stages.The resistor 49 is connected in the bridge branch of the full bridge between the terminals CANH / LINE+ and CANL / LINE- of the transmit / receive device 12, more precisely of the transmit module 121, for the bus wires 41, 42.

[0095] The STB connection is used in CAN to switch the transceiver 12 between a standby state (STANDBY mode) and an active state. In standby mode (STANDBY mode), the transceiver 12 is energy-saving but passive, and the STB connection is set to the voltage level or state Hl (HIGH). In the active state of CAN, which can also be referred to as the normal state, the transceiver 12 is active and can therefore participate in communication on bus 40. For this purpose, it is switched to one of the operating modes, as described below. In the active state, the STB connection is set to the voltage level or state LW (LOW), meaning it is always driven externally from the perspective of the transceiver 12.

[0096] According to Fig. 5, the communication control unit 11 has an operating mode selection module 113 for selecting the operating mode of the transmit / receive unit 12. The other modules of the unit 11 are not shown in Fig. 5. The operating mode selection module 113 has a first switch S1 and a second switch S2. The switches S1 and S2 can each be a transistor, in particular a CMOS transistor.

[0097] In the operating mode selection module 113, switches S1 and S2 are connected in series. This series connection of switches S1 and S2 is between terminals VIO and GND. The STB / ED terminal is connected to the connection of switches S1 and S2. Depending on the position of switches S1 and S2, the STB / ED terminal is pulled to the voltage level or state H1 (HIGH) or to the voltage level or state LW (LOW). On the transmit / receive unit 12, the communication interface determination module 125 has an evaluation block 1251, an operational amplifier or comparator 1252, and resistors R1 through R6.

[0098] Evaluation block 1251 is used to evaluate the state of the STB / ED connection when the transceiver 12 is active, i.e., when the transceiver 12 is not switched to a passive state. For example, active states for CAN XL are the operating modes SLOW or SIC, FAST_TX, FAST_RX, and for 10BASE-T1 S are the operating modes NORMAL, TRANSMITTING, CONFIG.

[0099] If the evaluation block 1251 detects that the STB / ED connection is pulled to the LW (LOW) state from the outside without the state handling for the CONFIG operating mode for 10BASE-T1 S having been completed beforehand, the transceiver 12 will behave according to the CAN standard, in particular the CAN-XL standard (CiA610-3), and enter or remain in the active CAN state, in particular CAN-XL. This is because such a state at the STB / ED connection necessarily indicates that the transceiver 12 is connected to a communication control unit 11, in particular a CAN or CAN-XL controller.

[0100] If the evaluation block 1251 detects that the STB / ED connection is being pulled to the LW (LOW) state from the outside, after the state handling for the CONFIG operating mode for 10BASE-T1 S has been completed, the transmit / receive device 12 will behave according to the 10BASE-T1 S standard for the function according to Open Alliance TC14 and enter the active state for the CONFIG operating mode. The behavior according to the 10BASE-T1 S standard is described in more detail with reference to Figures 6 and 7.

[0101] The evaluation block 1251 in Fig. 5 can, for example, be designed as analog hardware for distinguishing between the two communication standards CAN, in particular CAN XL, and 10BASE-T1 S. Such hardware is present for this distinction both for CAN, since the STB connection is configured as an input, and for 10Base-T1 S for detecting the CONFIG operating mode. This means that no significant additional circuitry is required for distinguishing between these two communication standards.

[0102] The comparator 1252 with the series resistors R1 to R6 is used to evaluate the state of the STB / ED connection when the transceiver 12 is passive. In such a passive state, the transceiver 12 is, for example, switched to STANDBY mode for CAN, especially CAN XL, and to LOW_POWER mode for 10BASE-T1 S.

[0103] In the communication interface selection module 125, the first resistor R1 is connected in series with a second resistor R2. The second resistor R2 is connected in series with a third resistor R3. The series connection of resistors R1, R2, R3 is connected between the VIO terminal and ground (GND). The STB terminal is connected to the junction of resistors R1 and R2. The first input of comparator 1251, which is at positive potential (+), is connected to the junction of resistors R1 and R2.

[0104] A fourth resistor, R4, is connected in series with a fifth resistor, R5. The fifth resistor, R5, is connected in series with the sixth resistor, R6. The series connection of resistors R4, R5, and R6 is connected between terminal VIO and ground (GND). A second input of comparator 1251, which is at negative potential (-), is connected to the junction of resistors R5 and R6. An electrical voltage, Uh, is applied between the inputs of comparator 1251. The output of comparator 1251 is connected to the operating mode selection module 123.

[0105] The choice of resistance values ​​for resistors R1 ... R6, as well as the exact circuit topology of block 125, depends on various implementation factors, such as current consumption, parasitic properties of the technology used, timing requirements, and other implementation factors. In a specific example, resistors R1 and R4 each have a lower resistance value than each of resistors R2, R3, R5, and R6, with resistor R4 having a lower resistance value than resistor R1. The resistance values ​​of resistors R2, R3, R5, and R6 can each be equal. Specifically, resistor R1 has a resistance value of 200 kΩ, resistor R4 has a resistance value of 100 kΩ, and resistors R2, R3, R5, and R6 each have a resistance value of 1 MΩ. The design of the resistance values ​​of resistors R1 ...However, R6 is not limited to this, as long as the following function of module 25 is fulfilled.

[0106] Figure 5 shows, for the preceding example, the case in which the operating mode selection module 113 sets the STB / ED connection for the first communication standard, in this example CAN. Therefore, switch S1 is closed and thus conductive. Switch S2 is open and thus non-conductive. Consequently, in a standalone CAN product, the STB C (standby pin) connection can be configured as an output of the communication control unit 11, in particular its CAN controller. Thus, the STB connection is an input of the transmit / receive unit 12 for CAN.

[0107] With the selection of resistance values ​​for resistors R1 ... R6 according to the preceding example, the STB / ED connection of module 125 is connected to the VIO connection with a significantly lower resistance than on the reference side, which has resistors R4, R5, R6. Therefore, comparator 1252 outputs the value or state Hl (HIGH). As a consequence, the transceiver 12 searches for a wake-up pattern according to the first communication standard, in particular for CAN or CAN-XL, on bus 40.

[0108] Fig. 6 shows that the transceiver 12 is connected in a 10BASE-T1 S bus system 1A for communication according to the 10BASE-T1 S standard between the communication control unit 11 A and the DC choke 13. The DC choke 13 is connected to the line connector 15 and thus to the bus wires 41, 42 and the terminating resistor 49 via an AC decoupling module 14, in particular a decoupling capacitor. The communication control unit 11 A is designed to control communication according to the 10BASE-T1 S standard. The AC decoupling module 14 can also be called an AC decoupling module. Otherwise, the same applies to the transceiver module 121 as described with reference to Fig. 3 and / or Fig. 4.

[0109] As shown in Fig. 7, the communication control unit 11A has an operating mode selection module 113A for selecting the operating mode of the transmit / receive unit 12. The other modules of the unit 11A are not shown in Fig. 7. The operating mode selection module 113A has a first switch S1 and a second switch S2. The switches S1 and S2 can each be a transistor, in particular a CMOS transistor. The communication interface determination module 125 of the transmit / receive unit 12 is constructed as previously described with reference to Fig. 5.

[0110] In the operating mode selection module 113A, switches S1 and S2 are connected in series. This series connection of switches S1 and S2 is connected between terminals VIO and GND. The STB / ED terminal is connected to the connection of switches S1 and S2.

[0111] The evaluation block 1251 proceeds for the active state of the transmitting / receiving device 12 as previously described with reference to Fig. 5.

[0112] The following applies to the passive state of the transmitting / receiving device 12.

[0113] Fig. 7 shows, for the preceding example of the resistance values ​​of resistors R1 ... R6 (Fig. 5), the case in which the operating mode selection module 113A sets the STB / ED connection for the second communication standard, in this example 10BASE-T1 S. Therefore, switch S1 is open and thus blocked. Additionally, switch S2 is open and thus blocked. Consequently, for 10BASE-T1 S, the ED connection is configured as an output of the transmit / receive unit 12. Therefore, the STB / ED connection, or ED, is configured as high-impedance on the communication control unit 11 A.

[0114] By selecting the resistance values ​​for resistors R1 ... R6 according to the preceding example, the pull-up resistor R1, which has a resistance value of, in particular, 200 kΩ, results in a higher voltage drop than resistor R4, which has a lower resistance value than resistor R1, in particular 200 kΩ. Therefore, on module 125, the STB / ED connection to the VIO connection has a significantly higher impedance than on the reference side, which has resistors R4, R5, and R6. Consequently, comparator 1252 outputs the value or state LW (LOW). As a result, the transceiver 12 searches for a wake-up pattern according to the second communication standard, in particular for 10BASE-T1 S, on bus 40A.

[0115] Unlike the circuit of the operating mode selection module 113A shown in Fig. 7, the STB / ED or ED connection for CONFIG mode is configured as an input, as previously described with reference to Fig. 5. In this case, the communication control unit 11A switches switches S1 and S2, as shown in Fig. 5 and as previously described. The ED connection can then be used as an MDIO (Management Data Input according to Open-Alliance TC14) data input, which stores settings in registers. According to the 10BASE-T1 S specification (Open-Alliance TC14, last published version 1.5 on November 8, 2022), the ED connection is connected to the VIO connection via a weak pull-up resistor. Therefore, unless externally driven, the STB / ED or ED connection is in the high (Hl) state, as previously described for Fig. 5 with reference to the STB connection for CAN.

[0116] If the transceiver 12 is configured as shown in Fig. 4, the signals shown in Figs. 8 to 11 are received or generated at the terminals of the transceiver 12. The transceiver 12 can be switched between different operating modes: SLEEP, SLOW or SIC, FAST_TX, FAST_RX, as specified in the international standard ISO 11898-1:2024 for CAN. Fig. 8 shows an example of the time course of a digital transmit signal TxD, which the transceiver 12 receives serially from the communication control unit 11 for a frame 450 of Fig. 2. The transmit signal TxD is divided over time t into the two communication phases 451 and 452, as described previously.

[0117] In the first communication phase (arbitration phase) 451, the transmitted signal TxD has bits with a bit time t_bt1 and the two distinct states Hl (high), in particular 1, and LW (low), in particular 0. In the second communication phase (data phase) 452, the transmitted signal TxD is at least temporarily a pulse-width modulated signal with a bit time t_bt2 and the two distinct states LVO, LV1. The bit time t_bt2 is shorter than the bit time t_bt1.

[0118] As shown in Fig. 8, the transmitter / receiver 12, like the transmitter / receiver 22, uses a first physical layer 451_P in the first communication phase (arbitration phase) 451 to send the transmit signal TxD from Fig. 8 as differential bus signals CAN_H, CAN_L according to Fig. 9 to the bus 40. The physical layer 451_P of the transmitter / receiver 12 has the operating mode SLOW or SIC, as described in more detail above and below.

[0119] However, in the second communication phase (data phase) 452, the transmit / receive device 12 according to Fig. 8 can use a second physical layer 452_P, which differs from the first physical layer 451_P, to send the transmit signal TxD from Fig. 8 as differential bus signals CAN_H, CAN_L according to Fig. 9 to the bus 40. The physical layer 452_P has two operating modes for the transmit / receive device 12, namely FAST_TX and FAST_RX, as described in more detail above.

[0120] As shown in Fig. 9, the signals CAN_H and CAN_L are serial analog signals and alternately have at least one dominant state 401 and / or at least one recessive state 402. In the dominant state 401, U = VCAN_H = 3.5 V and U = VCAN_L = 1.5 V. In the recessive state 402, U = VCAN_H = VCAN_L = 2.5 V. A dominant state 401 (dom) is driven in phase 451 with NRZ encoding of the transmit signal TxD when TXD = 0 or LW (LOW). A recessive state 402 (rec) is generated, or occurs in phase 451 with NRZ encoding of the transmit signal TxD, when TXD = 1 or Hl (HIGH).

[0121] After the arbitration in arbitration phase 451, one of the participating stations 10, 20, 30 is determined as the winner. If the respective participating station 10, 30 recognizes the signal in the first switching field 455 of Fig. 2 for the switch from the first to the second communication phase 451, 452, the associated transmit / receive device 12 switches its physical layer 451_P to the physical layer 452_P of the data phase 452 at the end of the arbitration phase 451, as described previously.

[0122] As shown in Fig. 9, the transmitter module 121 then generates the states L0 or L1 sequentially and thus serially with the physical layer 452_P for the signals CAN_H, CAN_L on bus 40 in the data phase 452 or in the second operating mode (FAST_TX), depending on the transmit signal TxD from Fig. 8. The state L0 (VCAN_H = 3.0 V, VCAN_L = 2.0 V) is driven by a pulse width modulation (PWM encoding) of the transmit signal TxD for a first PWM symbol in the transmit signal TxD. The state L1 (VCAN_H = 2.0 V and VCAN_L = 3.0 V) is driven in the transmit signal TxD for a second PWM symbol LV1, which differs from the first PWM symbol LVO, during pulse width modulation (PWM coding) of the transmit signal TxD.

[0123] The frequency of the signals CAN_H and CAN_L can be increased in data phase 452 according to the transmit signal TxD. In the example shown in Figures 8 and 9, the bit time or bit duration t_bt2 in data phase 452 is shorter than the bit time or bit duration t_bt1 in arbitration phase 451. Therefore, the net data transmission rate in data phase 452 is increased in the example shown in Figures 8 and 9 compared to arbitration phase 451.

[0124] In contrast, for example, the transmit / receive device 12 of the subscriber station 30 switches its Physical Layer 451_P at the end of the arbitration phase 451 from the first operating mode (SLOW or SIC) to the Physical Layer 452_P of the data phase 452 for the third operating mode (FAST_RX) of the transmit / receive device.

[0125] 12, if the participating station 30 in data phase 452 is only a receiver, i.e., not a sender, of frame 450

[0126] If the transmit / receive device 12, in particular via the signaling in the second switching field 458 of Fig. 2, detects that a switch from the data phase 452 back to the arbitration phase 451 is required, the transmit / receive device 12 switches from transmitting (operating mode FAST_TX) and / or receiving (operating mode FAST_RX) signals with the physical layer 452_P to transmitting and / or receiving signals with the physical layer 451_P. Thus, all transmit / receive devices 12 switch their operating mode to the first operating mode (SLOW or SIC) after the end of the data phase 452. Therefore, all transmit / receive devices 12 can not only switch between the bit times t_bt1 and t_bt2, but also switch their physical layer, as described above.

[0127] According to Fig. 10, in the arbitration phase 451, a differential signal VDIFF = CAN_H - CAN_L ideally forms on bus 40 over time t, with values ​​of VDIFF = 2V for dominant states 401 (dorn) and VDIFF = 0V for recessive states 402 (rec). The VDIFF waveform in phase 451 is shown on the left side of Fig. 10. In contrast, in the data phase 452, a differential signal VDIFF = CAN_H - CAN_L forms on bus 40 over time t, corresponding to states L0 and L1 from Fig. 9, as shown on the right side of Fig. 10. State L0 has a value VDIFF = 1 V. State L1 has a value VDIFF = -1 V.

[0128] The receiver module 122 can distinguish between states 401 and 402 using any two of the receive thresholds T1, T2, and T3, which lie within the ranges TH_T1, TH_T2, and TH_T3. For this purpose, the receiver module 122 samples the signals from Fig. 9 or Fig. 10 at times t_A, as shown in Fig. 10. To evaluate the sample result, the receiver module 122 uses, for example, the receive threshold T1 of 0.7 V and the receive threshold T2 of -0.35 V during the arbitration phase 451. In contrast, during the data phase 452, the receiver module 122 only uses signals that were evaluated using the receive threshold T3. When switching between the first to third operating modes (SLOW or SIC, FAST_TX, FAST_RX), which were previously described with reference to Fig. 8, the receiver module 122 switches the receive thresholds T2, T3 in each case.

[0129] The reception threshold T2 is used to detect whether bus 40 is free when the subscriber station 12 is newly connected to the communication on bus 40 and attempts to integrate itself into the communication on bus 40.

[0130] Upon receiving the corresponding signals from bus 40, each transmit / receive device 12 generates the associated receive signal RxD, as shown in Fig. 11. Ideally, the receive signal RxD of Fig. 11 has no time offset from the transmit signal TxD of Fig. 8.

[0131] Fig. 12 shows an example of a portion of the digital transmit signal TxD, which the transmit module 121 receives from the communication control unit 11 during the arbitration phase 451, and from which it generates the signals CAN_H and CAN_L for the bus 40. In Fig. 12, the transmit signal TxD changes from a state LW (Low) to a state Hl (High) and back to the state LW (Low).

[0132] As shown in more detail in Fig. 13, the transmitter module 121 generates the signals CAN_H and CAN_L for the bus wires 41 and 42 for the transmit signal TxD from Fig. 12, such that an additional state 403 (sic) is present. The state 403 (SIC) can have different durations, as shown by state 403_0 (SIC) during the transition from state 402 (rec) to state 401 (dorn) and state 403_1 (sic) during the transition from state 401 (dorn) to state 402 (rec). State 403_0 (sic) is shorter in duration than state 403_1 (sic). To generate signals according to Fig. 13, the transmitter module 121 is switched to SIC mode.

[0133] The passage through the short sic state 403_0 is not required in the CiA610-3, and its nature depends on the implementation. The duration of the "long" state 403_1 (sic) is specified for both CAN-SIC and the SIC operating mode in CAN-XL as t_sic < 530 ns, beginning with the rising edge of the transmit signal TxD in Fig. 12. In the "long" state 403_1 (SIC), the transmit module 121 should match the impedance between the bus conductors 41 (CANH) and 42 (CANL) as closely as possible to the characteristic impedance Zw of the bus line used. Here, Zw = 1000 Ω or 1200 Ω. This matching prevents reflections and thus allows operation at higher bit rates. For the sake of simplicity, the following will always refer to state 403 (sic) or sic- state 403.

[0134] The transmitter module 121 can be used to generate signals for bus 40 for the following CAN types: CAN-FD, CAN-SIC and CAN-XL.

[0135] Table 1: CAN types for transmitter module 121

[0136] Therefore, the transmitter module state 403 (sic) can be generated not only in CAN-SIC or CAN-XL (xl_sic). It can also be generated in CAN-FD. However, in CAN-FD, the duration of the transmitter module state 403 (sic) can be shorter than in CAN-SIC or CAN-XL.

[0137] The transmitter module 121 can thus generate two different bus states for CAN FD, three different bus states for CAN SIC, and five different states for CAN XL. If the transmitter / receiver unit 12 is configured as shown in Fig. 6, the signals shown in Figs. 14 to 17 are received or generated at the terminals of the transmitter / receiver unit 12. The transmitter / receiver unit 12 can be switched between different operating modes: LOW-POWER, NORMAL, TRANSMITTING, and CONFIG, as specified in the international standard IEEE 802.3cg™ for 10BAS ET 1 S.

[0138] Fig. 14 shows an example of a time course of a digital transmit signal Tx, which the transmit / receive device 12 receives from the communication control device 11 A of Fig. 6 in order to send the transmit signal Tx as differential bus signals LINE+, LINE- according to the 10BASE-T1 S standard to the bus 40A of the bus system 1 A;

[0139] According to Fig. 14, the transmit signal Tx is divided over time t into several communication phases 460, 461, 462, which are allocated to the individual subscriber stations 10, 20, 30 by a master subscriber station for transmission. Transmission permission is granted according to a round-robin algorithm, in which each subscriber station receives a transmission time slot in a transmission cycle, thus avoiding collisions on the bus 40. In the communication phases 460, 461, 462, the transmit signal Tx has bits with a bit time t_bt and the two distinct states Hl (high), specifically 1, and LW (low), specifically 0.

[0140] As shown in Fig. 15, the transmit / receive device 12 sends the transmit signal Tx from Fig. 14 as serial analog signals LINE+, LINE- to bus 40A. The signals alternately have at least one state V0, also called VLINE_POS, and / or at least one state V1, also called VLINE_NEG.

[0141] As shown in Fig. 16, a differential signal V_L is ideally generated on bus 40A over time t. In state V0, U = V_L (V0) = +0.5 V. In state V1, U = V_L (V1) = -0.5 V. The receiver module 122 can distinguish between states V0 and V1 using any two of the receive thresholds T1_ETH, T2_ETH, and T3_ETH, which lie in the ranges TH_T1, TH_T2, and TH_T3, respectively. For this purpose, the receiver module 122 samples the signals from Fig. 15 or Fig. 16 at predetermined times. To evaluate the sampling result, the receiver module 122 uses all three receive thresholds T1_ETH, T2_ETH, and T3_ETH in both NORMAL and TRANSMITTING modes. In contrast, the receiver module 122 uses only the two receive thresholds T2_ETH and T3_ETH in LOW-POWER operating mode. The receive threshold T1_ETH typically has a value of 0.0 V, the receive threshold T2_ETH typically has a value of +0.15 V, and the receive threshold T3_ETH typically has a value of -0.15 V.When switching between the operating modes (NORMAL, TRANSMITTING, LOW-POWER) previously described with reference to Fig. 8, the receiver module 122 switches the receive thresholds T1_ETH, T2_ETH, T3_ETH as required.

[0142] Upon receiving the corresponding signals from bus 40, each transmit / receive device 12 generates the associated receive signal Rx, as shown in Fig. 15. Ideally, the receive signal Rx has no time offset from the transmit signal Tx.

[0143] To set the configuration of the transmitting / receiving device 12 according to Fig. 4 or according to Fig. 6, the transmitting / receiving device 12 proceeds as described below.

[0144] After the supply voltage is switched on at the VCC terminal, also known as power-up, the transmitter module 121 remains in a high-impedance state on the bus side, if possible. "High-impedance state" here means that the resistance value of the internal resistor 1211 in the transmitter module 121 is set to a value at least as high as the resistance value of the bus termination resistor 49. This ensures that the bus 40, 40A is not blocked with potentially incorrect symbols.The transmitter module 121 remains in the high-impedance state on the bus side until the evaluation of the module 125 confirms whether a communication control device 11 is connected to the inputs of the transmitter / receiver device 12, so that the device 12 should behave according to the CAN, in particular CAN-XL, standard, or whether a communication control device 11 A is connected, so that the device 12 should behave according to the 10BASE-T1 S standard.

[0145] Once the testing and / or evaluation is completed using modules 123, 125, and optionally also module 124, and in particular once a decision has been made regarding the communication standard, the transmitting / receiving device 12 behaves according to the corresponding communication standard.

[0146] However, the transmit / receive unit 12 is designed to perform further evaluation for plausibility checks using modules 123, 125, and optionally also the optional module 124. This ensures that any faults, such as a short circuit at the STB / ED and / or TX / TXD terminals, are detected.

[0147] In its passive state, module 125 can detect the voltage level and / or impedance at the STB / ED connection. The transceiver 12 then searches for a corresponding wake-up pattern on bus 40, 40A to switch to the respective active operating modes: SLOW mode for CAN or CAN FD, SIC mode for CAN XL or CAN FD, and NORMAL mode for 10BASE-T1 S.

[0148] Second embodiment

[0149] According to a second embodiment, the transceiver 12 has no wake-up function. Consequently, the transceiver 12 has no SLEEP operating mode for the first communication standard, in particular CAN, and no LOW-POWER operating mode for the second communication standard, in particular 10BASE-T1 S. Such a transceiver 12 without a wake-up function, upon detection of voltage level and / or impedance at the STB / ED terminal, enters the respective active operating modes without a precondition wake-up, i.e., SLOW mode for CAN or CAN FD, SIC mode for CAN XL or CAN FD, and NORMAL mode for 10BASE-T1 S.

[0150] All previously described configurations of the transmit / receive device 12, the subscriber stations 10, 20, 30, 50, the bus systems 1, 1A, and the method implemented therein according to the exemplary embodiments and their modifications can be used individually or in all possible combinations. In addition, the following modifications are particularly conceivable.

[0151] The previously described bus system 1, 1A according to at least one of the embodiments is described using a bus system based on the CAN protocol or 10BASE-T1 S. However, the bus system 1 according to the embodiment can alternatively be a different type of communication network in which the signals are transmitted as differential signals.

[0152] It is advantageous, but not a necessary requirement, that at least one of the bus systems 1, 1A guarantees exclusive, collision-free access to bus 40 for at least certain periods of time by a participant station 10, 20, 30.

[0153] The bus system 1 according to at least one of the embodiments and their modifications is, in particular, a bus system in which communication between at least two of the participant stations 10, 20, 30 is possible according to two different CAN standards, such as CAN-HS, CAN FD, or CAN XL. Thus, the functionality of the previously described embodiment can be used, for example, with transmit / receive devices 12, 22 that are to be operated in such a bus system. The number and arrangement of the participant stations 10, 20, 30, 50 in each of the bus systems 1, 1A according to at least one of the embodiments and their modifications is freely selectable.

Claims

Claims 1) Transmit / receive device (12) for a subscriber station (10; 30; 50) of a serial bus system (1 ; 1 A), comprising a transmit module (121) for sending a digital transmit signal (TxD; Tx) as an analog differential signal (CAN_H, CAN_L; LINE+, LINE-) to a bus (40; 40A) of the bus system (1 ; 1 A) in order to send a message (45; 48) to at least one other subscriber station (10; 20; 30) of the bus system (1 ; 1 A), and a receive module (122) for receiving signals (CAN_H, CAN_L; LINE+, LINE-) from the bus (40; 40A) and for generating a digital receive signal (RxD; Rx) from the analog differential signal (CAN_H, CAN_L; LINE+, LINE-), a first connection (TXD / TX) for receiving the transmit signal (TxD; Tx) from a communication control unit (11 ; 11 A), a second connection (RXD / RX) for outputting the digital receive signal (RxD; Rx) to the communication control unit (11 ;11 A), a third connection (STB / ED) which can be switched as a digital output or input, and a COM-IF determination module (125) for evaluating, if the transmit / receive device (12) is switched to an operating mode in which the transmit / receive device (12) can actively perform communication via at least one of the first to third connections (TXD / TX; RXD / RX; STB / ED), whether the third connection (STB / ED) is switched as an output or as an input, wherein the transmit module (121) and the receive module (122) each have an configuration for two different communication standards (CAN; 10BASE-T1 S) and for communication in the serial bus system (1 ; 1 A) according to one of the; two communication standards (CAN; 10BASE-T1 S) can be set based on the evaluation result of the COM-IF determination module (125). 2) Transmitting / receiving device (12) according to claim 1, wherein the COM-IF- The determination module (125) has a comparator (1252) and resistors (R1, R2, R6) to determine the voltage level (Uh) and / or the To measure the impedance at the third connection (STB / ED). 3) Transmitting / receiving device (12) according to claim 2, wherein the comparator (1252) is connected between two series circuits (R1 , R2, R3; R4, R5, R6) of the resistors (R1 , R2, ..., R6), and wherein the two series circuits (R1 , R2, R3; R4, R5, R6) are connected in parallel. 4) Transmitting / receiving device (12) according to one of the preceding claims, wherein the COM-IF determination module (125), if the transmitting / receiving device (12) is switched to the operating mode in which the transmitting / receiving device (12) can actively perform communication via at least one of the first to third ports (TXD / TX; RXD / RX; STB / ED), and if the third port (STB / ED) is configured as an input, is additionally designed to evaluate whether a predetermined property of one of the two communication standards (CAN; 10BASE-T1 S) has been implemented or not. 5) Transmitting / receiving device (12) according to claim 4, wherein the transmitting / receiving device (12) is switched to the CONFIG operating mode in which the transmitting / receiving device (12) can actively perform communication via the third port (STB / ED), and wherein the predetermined property of the communication standard of the two communication standards (CAN; 10BASE-T1 S) is the state handling according to 10BASE-T1 S. 6) Transmit / receive device (12) according to one of the preceding claims, further comprising a COM-IF acquisition module (124) for evaluating the digital transmit signal (TxD; Tx) at the first terminal (TXD / TX) in order to configure the transmit module (121) and the receive module (122) for communication in the serial bus system (1 ; 1A) according to one of the two communication standards (CAN; 10BASE-T1 S). 7) Transmitting / receiving device (12) according to one of the preceding claims, further comprising an operating mode selection module (123) for selecting an operating mode of the transmitting module (121) and / or the receiving module (122) on the basis of an evaluation result of the COM-IF determination module (125). 8) Transmitting / receiving device (12) according to claim 7, wherein the operating mode selection module (123) is configured to also evaluate the transmit signal (TxD; Tx) at the first connection (TXD / TX) for selecting the operating mode of the transmitting module (121) and / or the receiving module (122). 9) Transmitting / receiving device (12) according to claim 7 or 8, wherein the COM-IF determination module (125) further evaluates, after passing an evaluation result to the operating mode selection module (123), whether the third connection (STB / ED) is switched as an output or as an input. 10) Transmitting / receiving device (12) according to one of the preceding claims, wherein the transmitting module (121) is configured to generate the analog differential signals (CAN_H, CAN_L) in a first communication phase (451) of the message (45) with a different physical layer (451_P) than in a second communication phase (452) when using one communication standard (CAN XL) of the two communication standards (CAN; 10BASE-T1 S). 11 ) Transmitting / receiving device (12) according to one of the preceding claims, wherein the two communication standards are CAN XL and 10BASE-T1 S. 12) Subscriber station (10; 30; 50) for a serial bus system (1 ; 1 A), comprising a transmit / receive device (12) according to one of the preceding claims, and a communication control device (11 ; 11A) for controlling the communication in the bus system (1 ;1A) and for generating the transmit signal (TxD, Tx). 13) Participant station (10; 30; 50) according to claim 12, wherein the participant station (10; 30; 50) is configured for communication in a bus system (1 ; 1 A) in which at least temporarily exclusive, collision-free access of a participant station (10; 30; 50) to the bus (40; 40A) of the bus system (1 ; 1 A) is ensured. 14) Gateway (5) for forwarding messages (45; 46; 47; 48) between at least a first bus system (1) and a second bus system (1A), with at least two transmit / receive devices (12) according to one of claims 1 to 11, wherein one of the at least two transmit / receive devices (12) of the gateway (5) is connected to the first bus system (1) and another of the at least two transmit / receive devices (12) is connected to the second bus system (1A). 15) Method for communication in a serial bus system (1 ; 1 A), wherein the method is carried out with a transmit / receive device (12) for a subscriber station (10; 30; 50) of the bus system (1 ; 1 A), which has a transmit module (121), a receive module (122), a first port (TXD / TX), a second port (RXD / RX), a third port (STB / ED) which is switchable as a digital output or input, and a COM-IF determination module (125), wherein the transmit module (121) and the receive module (122) each have a The design accommodates two different communication standards (CAN; 10BASE-T1 S), and the procedure includes the following steps: Receiving, at the first terminal (TXD / TX), a digital transmit signal (TxD; Tx) from a communication control device (11; 11A), wherein the transmit signal (TxD; Tx) is configured for transmission as an analog differential signal (CAN_H, CAN_L; LINE+, LINE-) to a bus (40; 40A) of the bus system (1; 1A) in order to send a message (45) to at least one other subscriber station (10; 20; 30; 50) of the bus system (1A), Evaluate, using the COM-IF determination module (125), if the transmit / receive device (12) is switched to an operating mode in which the transmit / receive device (12) can actively perform communication via at least one of the first to third ports (TXD / TX; RXD / RX; STB / ED), whether the third port (STB / ED) is configured as an output or as an input, Switching of the transmit module (121) and the receive module (122) based on the evaluation of the COM-IF determination module (125) for communication in the serial bus system (1 ; 1A) according to one of the two communication standards (CAN; 10BASE-T1 S), Sending, with the transmit module (121), the transmit signal (TxD; Tx) as an analog differential signal (CAN_H, CAN_L; LINE+, LINE-) to the bus (40; 40A) according to the set communication standard, and / or Receiving, with the receiver module (122), analog differential signals (CAN_H, CAN_L; LINE+, LINE-) from the bus (40; 40A) to output a digital receive signal (RxD; Rx) according to the set communication standard to the communication control unit (11 ; 11A).

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