Transmitting / receiving device for a commander subscriber station or a responder subscriber station of a serial bus system and method for communication in a serial bus system

Abstract

It provides a transmit / receive device (12; 22) for a commander subscriber station (100) or a responder subscriber station (101; ...; 10N) of a serial bus system (1), a responder subscriber station (101 ... 101N) for a serial bus system (1), a commander subscriber station (100) for the serial bus system (1), and a method for communication in a serial bus system (1). The transmit / receive device (12; 22) has a transmit module (121; 221) for sending a digital transmit signal (TxD) based on a frame (450) for a message (45) to be sent over the bus (40) as a differential signal (CAN_H, CAN_L) to a bus (40) of the bus system (1), a receive module (122;222) for receiving a differential signal (VDIFF) from the bus (40) and for generating a digital receive signal (RxD) from the differential signal (VDIFF) received from the bus (40) and for forwarding the digital receive signal (RxD) to a communication control unit (11; 21) for evaluating the digital receive signal (RxD) based on a predetermined frame (450) for a message (45) from the bus (40), and an operating mode switching module (19; 29) for switching the transmit module (121; 221) and the receive module (122; 222) between messages (45) on the bus (40) into a first operating mode (SIC) or for switching the transmit module (121; 221) and the receive module (122; 222) to transmit or receive a message (45) into a second or third operating mode (FAST_TX; FAST_RX), wherein the operating mode switching module (19; 29) is configured, the transmit module (121; 221) and the receive module (122;222) to switch from the first operating mode (SIC) to the third operating mode (FAST_RX) to receive a message (45) from the bus (40) when the operating mode switching module (19; 29) has received an edge from the bus (40).

Description

Technical field

[0001] The present invention relates to a transmit / receive device for a commander subscriber station or a responder subscriber station of a serial bus system and a method for communication in a serial bus system. State of the art

[0002] Bus systems are used in many areas of technology for communication between technical devices, such as sensors and control units.

[0003] It is known that Classical CAN and / or CAN FD are used for communication between devices in vehicles and / or other technical equipment; both are standardized in the international standard ISO 11898-1:2015. CAN FD enables communication on the bus at, for example, 2 Mbit / s or 5 Mbit / s. Each message can contain up to 64 bytes.

[0004] Furthermore, CAN XL can be used, which is compatible with CAN FD and specified in ISO / DIS11898-1:2024. CAN XL enables communication on the bus with bit rates up to 20 Mbit / s and a data volume per message of up to 2048 bytes.

[0005] The participating stations of such a bus system are also called nodes. These participating stations have a microcontroller that, in the case of CAN XL, supports all the functions of the aforementioned standards for Classical CAN and / or CAN FD and / or CAN XL.

[0006] CAN XL offers the significant advantage of allowing data exchange between participant stations on the bus system at considerably higher speeds than with Classical CAN or CAN FD. However, the requirements for communication devices to operate with CAN XL, and therefore their costs, are higher than for communication devices designed only for Classical CAN and / or CAN FD.

[0007] The cost aspect is particularly disadvantageous for participant stations that only have to perform very simple functions. Such participant stations include, for example, an indicator light, especially a light-emitting diode (LED), which is to be switched on or off and / or change color as needed, controlled by the microcontroller of another participant station. Another example is a sensor that is to transmit its data to the microcontroller of another participant station from time to time.

[0008] Therefore, there is a desire to utilize the advantages of CAN XL while reducing communication costs. However, due to the complexity of CAN XL, this is not easily achievable. Disclosure of the invention

[0009] Therefore, the object of the present invention is to provide a transmit / receive device for a commander or responder station of a serial bus system and a method for communication in a serial bus system, which solve the aforementioned problems. In particular, a transmit / receive device for a commander or responder station of a serial bus system and a method for communication in a serial bus system are to be provided, in which communication in the serial bus system is possible with high error robustness, a higher bit rate than previously possible, and a high net data transfer rate, but at lower costs than previously possible.

[0010] This problem is solved by a transmit / receive device for a commander substation or a responder substation of a serial bus system, comprising the features of claim 1. The transmit / receive device has a transmit module for sending a digital transmit signal, based on a frame for a message to be sent over the bus, as a differential signal to a bus of the bus system, a receive module for receiving a differential signal from the bus and for generating a digital receive signal from the differential signal received from the bus and for forwarding the digital receive signal to a communication control unit for evaluating the digital receive signal based on a predetermined frame for a message from the bus.an operating mode switching module for switching the transmit module and the receive module between messages on the bus into a first operating mode or for switching the transmit module and the receive module to transmit or receive a message into a second or third operating mode, wherein the operating mode switching module is configured to switch the transmit module and the receive module from the first operating mode to the third operating mode for receiving a message from the bus when the operating mode switching module has received an edge from the bus.

[0011] The described transceiver for a subscriber station (commander or responder) can be implemented as a CAN XL transceiver or CAN SIC XL transceiver with a significantly reduced range of functions and / or significantly lower circuit design complexity. This is made possible by communication with CAN XL-light, as the bus system no longer uses a dominant bus state, which, compared to the other bus states, requires significantly higher circuit complexity for control. This communication can also be referred to as extended CAN XL light or CAN XL light Extended.

[0012] Eliminating the dominant bus state also enables 100% impedance symmetry between the bus signal connections. In a CAN bus system, the connections CANH and CANL can be designated CAN_H and CAN_L for the differential bus signals. Since the dominant bus state forces an asymmetry at the CAN_H and CAN_L connections, which reduces the transmittable bit rate and can increase electromagnetic emissions from the receiving station, the design of the described receiving station (responder) offers a significant advantage in terms of signal quality. Furthermore, eliminating the dominant bus state saves semiconductor area, particularly silicon area, and ensures identical circuitry at the bus connections for bus states L0 and L1. This results in advantages both in terms of improved interference immunity of the receiving station and reduced electromagnetic emissions from the receiving station.

[0013] A significant advantage of the described transceiver for a commander or responder station is the substantial reduction in system-level costs. One reason for this cost reduction is that, at least in the responder station, a CAN XL transceiver or CAN SIC XL transceiver with a considerably reduced feature set can be used. Another reason for the cost reduction is that a high-precision clock is not required in the responder station, as bus communication does not necessitate arbitration, and therefore this is neither supported nor performed by the responder station.During arbitration, an identifier (ID) in an arbitration field is used to negotiate bitwise between participating stations on the bus which station wants to send the message with the highest priority and therefore receives exclusive access to the bus of bus system 1 for transmission during the subsequent data phase, as is known, for example, from the CAN bus system according to ISO / DIS11898-1:2024. The clock speed can be up to 5 times less precise than in CAN XL.

[0014] Another reason for the significantly reduced costs is that a protocol controller with a considerably reduced range of functions can be used in the responder subscriber station, which enables savings of more than 50%.

[0015] The reduced costs for the modified CAN XL transceiver or modified CAN SIC XL transceiver result from a smaller semiconductor footprint and reduced circuit design complexity. The semiconductor is primarily silicon, as previously mentioned.

[0016] The design of the described transceiver for a commander substation or a responder substation enables cost-effective integration of the responder onto a single ASIC (Application-Specific Integrated Circuit) in a mixed-semiconductor process, such as bipolar transistor(s), CMOS transistor(s), and DMOS transistor(s) (BCD technology). After receiving a request from the commander, the responder substation (responder) transmits its functional information, such as a sensor value, to the commander substation (commander) via a CAN XL message.

[0017] The described transceiver for a commander or responder station is suitable for extended CAN XL light communication between commander and responder stations with bit rates higher than those currently possible with CAN FD. Specifically, the bit rates are greater than 10 Mbit / s, and in particular up to 20 Mbit / s. This means that significantly higher bit rates are possible with the described communication between commander and responder stations than with CAN FD Light, which is limited to 2 Mbit / s or 5 Mbit / s.

[0018] Furthermore, the resulting Commander and Responder stations allow significantly larger data packets to be transmitted over the bus per message than CAN FD light. The described Responder station is designed for the transmission of 2048 bytes or more, specifically 4096 bytes, per message over the bus, whereas CAN FD light is limited to 64 bytes.

[0019] A further advantage is that the described transceiver for a commander or responder station enables a combined transceiver product that can support both CAN XL light Extended and another standard for transmitting differential signals, in particular 10BASE-T1S. This increases the range of applications and thus flexibility for the user.

[0020] Overall, the described transmit / receive device contributes to making the bus system more cost-effective at data rates up to 20 Mbit / s and data packets of approximately 2 kByte or more in a message, while still enabling robust and reliable communication with differential signals.

[0021] Further advantageous configurations of the transmitting / receiving device are specified in the dependent claims.

[0022] It is conceivable that the operating mode switching module is designed to switch the transmitting module and the receiving module from the third operating mode to the first operating mode when the operating mode switching module has received a predetermined signal from the communication control unit.

[0023] The transmit / receive device can be configured to use a first physical layer in the first operating mode to generate only a first bus state on the bus, wherein the transmit / receive device is configured to use a second physical layer, which differs from the first physical layer, in the second and third operating modes to generate a second and third bus state as symmetrical bus states for the differential signals on the bus.

[0024] It is possible that the single bus state for differential signals on the bus in the first operating mode differs from each of the symmetrical bus states for differential signals on the bus in the two other operating modes for which the transmit / receive device is designed in the two other operating modes.

[0025] The transmit / receive device can be configured to activate a predetermined receive threshold for generating a digital receive signal from the differential signal received by the bus when switching from the first operating mode to the third operating mode, but to deactivate the predetermined receive threshold when switching from the third operating mode to the first operating mode.

[0026] The previously described transmit / receive device can be part of a responder station for a serial bus system, which also has a communication control device for controlling communication between the responder station and a commander station of the bus system and for evaluating at least one signal received from a bus of the bus system based on a predetermined frame for a message from the bus, wherein the communication control device is configured to signal to the transmit / receive device at each bit of the predetermined frame which operating mode the transmit / receive device is to be switched to.

[0027] The communication control device can be configured to send a message via the bus to the commander participant station only when the commander participant station has requested the responder participant station to do so by means of a send request.

[0028] The responder subscriber station may also have an operating mode signaling module to signal which of three different operating modes the transmit / receive device is to be switched to, wherein the operating mode signaling module may be configured to signal a change of operating mode at the beginning of the message in the transmit signal when the transmit / receive device is to be switched to an operating mode for sending the message to the bus, and wherein the operating mode signaling module is configured to signal a change of operating mode at the beginning of the message when the transmit / receive device is switched to an operating mode for receiving the message from the bus.

[0029] The responder subscriber station may be designed to use a CAN XL frame in XLFF format as a predetermined frame.

[0030] The previously described transmit / receive device can be part of a commander subscriber station for a serial bus system, which also has a communication control device for controlling communication between the subscriber station and a responder subscriber station of the bus system and for evaluating at least one signal received from a bus of the bus system based on a predetermined frame for a message from the bus, wherein the communication control device is configured to signal to the transmit / receive device at each bit of the predetermined frame which of the operating modes the transmit / receive device is to be switched to.

[0031] The communication control unit of the Commander participant station can be configured to request the Responder participant station to send a message via the bus to the Commander participant station by means of a send request.

[0032] The Commander substation may also have an operating mode signaling module to indicate which of three different operating modes the transmit / receive device should be switched to. This operating mode signaling module may be configured to signal a change of operating mode at the beginning of the message when the transmit / receive device is to be switched to a mode for sending the message to the bus, and to signal a change of operating mode at the beginning of the message when the transmit / receive device is switched to a mode for receiving the message from the bus. The described Commander substation may support more than one frame format.Therefore, the synchronization function of the commander substation can be enabled or disabled, particularly by setting the value of a configuration bit, as previously mentioned. If synchronization (re-synchronization to the bitstream seen at the RXD port) is disabled, the commander substation no longer supports arbitration and can thus only be used as a commander.

[0033] If the commander substation does not need to be compatible with the current ISO 11898-1 standard, it can be designed more cost-effectively than one that is. This is because no arbitration is required for communication between the commander and responder on the bus. However, the commander substation can also support arbitration and therefore communicate with other substations on the bus according to the CAN CC, CAN FD, CAN XL, and CAN FD / XL standards. For arbitration, the commander substation uses a clock with low tolerance or a high-precision clock. In contrast, the responder substation can have a high clock tolerance because it is allowed to account for the majority, e.g., 90%, of the clock tolerance.

[0034] The commander participant station described above and at least one responder participant station described above can be part of a bus system comprising a bus and at least two participant stations which are interconnected via the bus in such a way that they can communicate serially with each other, wherein each of the at least two participant stations also has a transmit / receive device for sending a transmit signal to the bus of the bus system and / or for receiving a signal from the bus of the bus system.

[0035] The aforementioned problem is further solved by a method for communication in a serial bus system according to claim 14. The method is implemented with a previously described commander participant station and a previously described responder participant station.

[0036] The procedure offers the same advantages as previously mentioned in relation to the participant stations.

[0037] In this method, unlike a CAN XL substation, it is possible that the commander substation and the responder substation do not perform bit monitoring when sending a message, that the commander substation does not send an ACK bit when it has correctly received a message, that the responder substation does not send an ACK bit when it has correctly received a message, that the commander substation and the responder substation do not perform error signaling, that the commander substation and the responder substation do not use overload frames, and that the commander substation and the responder substation do not perform automatic retransmission.and that the Commander Participant Station and the Responder Participant Station do not perform an automatic shutdown of the Responder Participant Station upon detecting a predetermined number of communication errors.

[0038] 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. Drawings

[0039] The invention is described in more detail below with reference to the accompanying drawing and by means of exemplary embodiments. The drawing shows: Fig. 1 a simplified block diagram of a bus system according to a first embodiment; Fig.2 the format of CAN XL frames according to the standard ISO / DIS11898-1:2023 for a message that can be sent by a participating station of the bus system according to the first embodiment; Fig. 3 a simplified schematic block diagram of a first participant station (Commander) of the bus system according to the first embodiment; Fig. 4 a time course of a digital transmission signal in the operation of the bus system at the first subscriber station which is connected to the same bus of the bus system with at least one second subscriber station, and when communication on the bus is using the CAN XL standard; Fig. 5. A time course of bus signals CAN_H and CAN_L at the first participating station, when the first participating station is ready to send the transmit signal from Fig. 4. The bus uses the standard of CAN XL or CAN XL light; Fig.6. A time course of a differential voltage VDIFF of the bus signals CAN_H and CAN_L on the bus as a result of the signals from Fig. 5; Fig. 7 a time course of a digital received signal generated by the first or a second subscriber station from a signal received by the bus, which is based on the transmitted signal from Fig. 4 based; Fig. 8 a temporal profile of a digital transmission signal in the operation of the bus system at the first subscriber station during communication according to the first embodiment, in which the first subscriber station uses CAN XL light Extended; Fig. 9 a time course of bus signals CAN_H and CAN_L at the first subscriber station according to the first embodiment, if the first subscriber station uses CAN XL light Extended; Fig.10 a time course of a differential voltage VDIFF of the bus signals CAN_H and CAN_L on the bus as a result of the signals from Fig. 9; and Fig. 11 a simplified schematic block diagram of a second subscriber station (responder) of the bus system according to the first embodiment.

[0040] In the figures, identical or functionally equivalent elements are provided with the same reference symbols unless otherwise specified. Description of the exemplary implementations

[0041] Fig. Figure 1 shows, as an example, a bus system 1, which is fundamentally designed for a CAN XL bus system and / or variations thereof, as described below. Bus system 1 can be used in a vehicle, in particular a motor vehicle, an aircraft, etc., or in a hospital, etc.

[0042] In Fig.In bus system 1, a bus 40 is connected to which one commander station 100 and several responder stations 101, 102, 103 ... 10N are connected. N is a natural number greater than or equal to 1.

[0043] Bus 40 is connected to responder participant stations 101, 102, 103 ... 10N. Bus 40 can serve a first bus route 41 ( Fig. 3) and a second bus line 42 ( Fig. 3) have, which are in Fig. 1 are not shown. The bus wires can also be called CAN_H and CAN_L and serve for electrical signal transmission after coupling of the dominant levels or generation of recessive levels or other levels for a signal in the transmit state.

[0044] The Commander Participant Station 100, for example, is a control unit of a motor vehicle or other technical system, as described in more detail below. The Responder Participant Stations 101, 102, 103 ... 10N can, for example, include at least one sensor, at least one display device, at least one actuator, or at least one transmitter, etc., of a motor vehicle or other technical system, as described in more detail below.

[0045] As in Fig. As shown in Figure 1, the Commander subscriber station 100 has a communication control unit 11, a transmit / receive unit 12, a synchronization module 15, an operating mode signaling module 18, and an operating mode switching module 19. Each of the Responder subscriber stations 101, 102, 103 ... 10N has a communication control unit 21, a transmit / receive unit 22, a synchronization module 25, an operating mode signaling module 28, and an operating mode switching module 29.

[0046] The transmit / receive equipment 12, 22 of the subscriber stations 100 ... 10N are each directly connected to bus 40, even if this is in Fig. 1 is not illustrated.

[0047] The Commander subscriber station 100 is configured to create messages 45 in the form of signals. Optionally, the Commander subscriber station 100 can be configured to alternatively create messages 46 for CAN FD or another CAN type. In the example described below, the Commander subscriber station 100 is configured to send only messages 45 in the form of signals to one of the subscriber stations 101 ... 10N via bus 40.

[0048] Participant stations 101 ... 10N in Fig.In the example described below, the following configuration is used to create messages 45 in the form of signals and send them via bus 40 to the Commander participant station 100. The messages 45 can be transmitted serially between participant station 100 and one of the participant stations 101 to 10N.

[0049] The communication control units 11 and 21 each serve to control communication between the subscriber station 100 and one of the subscriber stations 101 ... 10N via bus 40. The communication control units 11 and 21 generate a transmit signal TxD as needed, which is subsequently used in relation to Fig. 4 is described in more detail. In addition, the communication control units 11, 21 read and decode a received signal RxD, which is subsequently described in relation to Fig. 7 is described in more detail.

[0050] The communication control unit 11 can be implemented, at least partially, like a conventional CAN XL controller according to ISO / DIS 11898-1:2024 or like a conventional CAN XL light controller. Thus, depending on the implementation, the communication control unit 11 can support the transmission and / or reception of seven different frame formats: four Classical CAN frame formats, two CAN FD frame formats with 11-bit or 29-bit identifiers, and one CAN XL frame format. The frame formats, particularly for CAN FD, are known from ISO 11898-1:2015 and are therefore not described in detail here. The aforementioned frame formats are divided into two communication phases: an arbitration phase and a data phase, as described in more detail below.

[0051] The communication control unit 11 of Fig.Module 1 is designed to use a CAN-XL message 45 for communication with the subscriber station 101 ... 101 N. Modules 18 and 19 are used to send and receive the CAN-XL message 45. Optionally, the respective synchronization modules 15 and 25 are also used. The CAN-XL message 45 is based on a CAN-XL format, which, with regard to Fig. 2 is described in more detail. The synchronization modules 15 and 25 are only required for bit rates greater than 1 Mbit / s. The operating mode signaling module 18 serves to signal to the transmit / receive device 12, when sending the CAN-XL message 45, that and when the transmit / receive device 12 needs to switch its operating mode. The operating mode switching module 19 serves to switch the operating mode of the transmit / receive device 12 as needed when sending or receiving message 45, as described in more detail below.

[0052] The communication control unit 21 is at least partially implemented as a CAN-XL-light controller. For this purpose, the synchronization module 25 is provided, which is designed to be compatible with the synchronization module 15. The communication control unit 21 creates messages 45, for example, the CAN XL messages with a frame of Fig. 2, and is designed to read the messages 45 from the subscriber station 100. The operating mode signaling module 28 serves to signal to the transmit / receive device 22, when sending the CAN-XL message 45, that and when the transmit / receive device 22 must switch its operating mode. The operating mode switching module 29 serves to switch the operating mode of the transmit / receive device 12 as needed when sending or receiving the message 45, as described in more detail below.

[0053] The communication described below in bus system 1 can also be called CAN XL Light Extended.

[0054] To communicate with one of the participant stations 101 ... 10N, participant station 100 (Commander) sends a send request to the desired participant station 101 ... 10N via bus 40. The send request is made by sending a message 45, which is based on a CAN-XL frame 450 that is in Fig. 2 is shown. A responder subscriber station 101 ... 10N only sends a message 45 if it is on a CAN-XL frame according to Fig. 2 is based on bus 40, which is sent to the Commander substation 100 when substation 100 has requested substation 101 ... 10N to do so by means of a send request. The request to send is encoded in frame 450 sent by substation 100 (Commander), e.g., in a data field that is in Fig. 2 is shown and described below.

[0055] In the CAN XL Light bus access method and in the method according to CAN XL Light Extended, only the participant station 100 (Commander) initiates communication with the responders. For this purpose, the participant station 100 (Commander) sends a message 45 in a frame 450 according to Fig.2. After message 45 is completed, the participating station 100 (Commander) can grant at least one of the N responders a certain time window in which it can send a message 45 to one of the N responder participating stations 101...10N, thereby answering the send request. The participating station 100 (Commander) can grant a certain time window in which up to N of the participating stations 101...10N (Responders) can send a message 45 successively. Accordingly, the signals, and thus the data, of the participating stations 101...10N (Responders) are transmitted in predetermined time intervals or time slots on bus 40 as the single channel. For example, each of the participating stations 101...10N (Responders) is configured to recognize and use its assigned time slot.

[0056] Thus, station 100 acts as a commander / queryer with respect to stations 101 ... 10N, and each of the stations 101 ... 10N acts as a responder. The CAN XL Light bus access method and the CAN XL Light Extended bus access method are each a combination of polling and time-division multiplexing. Time-division multiplexing is also called TDM or Time Division Multiplexing, or TDMA for Time Division Multiple Access.

[0057] In the following, participant station 100 can also be referred to as CAN-XL-light-Extended-Commander and participant station 101 ... 10N as CAN-XL-light-Extended-Responder.

[0058] Fig.Figure 2 shows a frame 450, which can be created by participant station 100 or one of the participant stations 101 ... 10N, for a message 45 in the CAN XL frame format, also called XLFF format. However, participant stations 100 ... 10N are not connected to the frame 450 of Fig. 2 are limited, but can use a different framework for communication on bus 40.

[0059] The CAN XL frame 450 according to Fig.2 can be provided by the subscriber station (Commander) 100 or the communication control unit 11, namely encoded in a digital transmit signal TxD, to the associated transmit / receive unit 12 in order to send the frame 450 on bus 40 to another subscriber station of bus system 1. Alternatively, the CAN XL frame 450 can be provided by a subscriber station (Responder) 101 ... 10N or its communication control unit 21, namely encoded in a digital transmit signal TxD, to the associated transmit / receive unit 22 for transmission on bus 40.

[0060] Frame 450 is divided into two communication phases, which in CAN, CAN FD, and CAN XL are called arbitration phase 451 (first communication phase) and data phase 452 (second communication phase). Frame 450 begins and ends in arbitration phase 451, even though no arbitration takes place during communication on bus 40, as described in more detail below.

[0061] In CAN XL light Extended, the participating stations 100 ... 10N use symmetrical '1' and '0' levels for the transmission of the frame 450 on bus 40 in both the first communication phase (arbitration phase) 451 and the second communication phase (data phase) 452. Fig. 1, instead of recessive and dominant levels as with CAN FD and the arbitration phase 451 in CAN XL, as previously described.

[0062] The frame 450 from Fig.The second step begins with a SOF bit and contains an arbitration field 453, a control field 454 with an ADS field for switching between communication phases 451 and 452, a data field 455, a checksum field 456, an acknowledgement field 457, and an end-of-frame field EOF. The CAN-XL format is defined in ISO / DIS11898-2:2024.

[0063] Bits in the first communication phase (arbitration phase) 451 of frame 450 may have a longer bit time than bits in the second communication phase (data phase) 452. The switch from the bits with the bit time of the first communication phase (arbitration phase) 451 to the bits with the bit time of the second communication phase (data phase) 452 takes place at the beginning of the control field 454 in an ADH bit.

[0064] In CAN XL, CAN XL light and CAN XL light Extended, bits that are on their lower line in Fig.2 are represented with a thick line, in which frame 450 is sent as dominant or 'L0', specifically L = low or '0'. Bits that are at their top line in Fig. Bits 2, represented by a thick line, are transmitted in frame 450 as recessive or 'L1', specifically H = high or '1'. Such bits, which are in Fig. 2, represented by a thick line, have a predetermined fixed or set value within frame 450.

[0065] Arbitration field 453 of arbitration phase 451 is provided for at CAN XL to be used for framework 450 of Fig. 2. Arbitration is performed using the identifier (ID). However, as mentioned previously, in CAN XL light and CAN XL light Extended, the participating stations 100 ... 10N do not perform arbitration.

[0066] In the first communication phase (arbitration phase) 451, a bit rate of less than or equal to 20 Mbit / s can be used in the present embodiment. However, the same bit rate can alternatively be used in phases 451 and 452. The latter will be the main use case for CAN XL light Extended in order to be able to use the high transmission speed of up to 20 Mbit / s throughout the entire framework.

[0067] According to Fig. In data phase 452, in addition to a portion of the control field 454 of the frame 450, the payload data of the CAN-XL frame 450 or the message 45 from the data field 455, as well as the checksum field 456, are transmitted. In the present embodiment, a data bit rate of up to 20 Mbit / s is used in data phase 452.

[0068] According to Fig.Frame 450 contains an ADS field and a DAS field. In CAN XL, these two fields are used to switch the bit rate and to switch the transmit / receive device 12 (transceiver) from SIC mode to FAST_TX or FAST_RX modes, and vice versa. In CAN XL light Extended, these fields only function to switch the bit rate if a slower bit rate is selected in the arbitration phase (451) than in the data phase (452).

[0069] Generally, two different stuffing rules are applied when generating frame 450. Up to the FDF bit in arbitration field 453, the dynamic bit stuffing rule of CAN FD applies, or for a frame 450 of Fig.2, so that after 5 consecutive identical bits, an inverse stuff bit is to be inserted. In data phase 452 up to the FCP field, a fixed stuffing rule applies, so that after a fixed number of bits, a fixed stuff bit is to be inserted that is the inverse of the preceding bit.

[0070] In the present embodiment, where the commander and responder understand only CAN XL frames, the res bit known from CAN FD, which is designated as the XLF bit in frame 450, has no function for switching from the CAN FD format to the CAN XL format. However, the frame formats of CAN FD and CAN XL are identical up to the res bit or XLF bit. In CAN XL light Extended, the XLF bit is transmitted as 1 (L1) to identify frame 450 as a CAN XL frame. For a CAN FD frame, the communication control unit 11 sets the bit as 0 or L (low), i.e., as the dominant res bit. If the receiving station 100 is at least partially a conventional CAN XL receiving station, it also supports CAN FD. Receiving stations 100 to 10N, on the other hand, are configured for CAN XL light Extended and support only frame 450 (CAN XL format) for sending and receiving.

[0071] Following the XLF bit in frame 450 is a resXL bit, which is a dominant bit for future use. For frame 450 in CAN XL light Extended, the resXL bit must be sent as 0, i.e., L0.

[0072] Following the resXL bit in frame 450 is a sequence ADS (Arbitration Data Switch) into an ADS field, which is described previously in connection with the DAS field.

[0073] The fields up to the beginning of data field 455 are not described in detail here. Data field 455 can be up to 2048 bytes or more. The length of data field 455 is encoded in bits 0 to 10 of the DLC field.

[0074] Following data field 455 in frame 450 is the checksum field 456, containing a frame checksum FCRC and an FCP field. FCP stands for Frame Check Pattern. The FCP field consists of 4 bits, including the bit sequence 1100. A receiver of frame 450 (receiving node) uses the FCP field to check whether it is bit-synchronized with the transmitted data stream. Furthermore, a receiving node synchronizes itself to the falling edge of the FCP field.

[0075] The FCP field is followed by the frame termination field 457. The frame termination field 457 consists of two fields: the DAS field, as described before and below, and the confirmation field or ACK field with at least one ACK bit and the ACK-Dlm bit.

[0076] The DAS field has already been described previously.

[0077] As mentioned, in CAN XL light Extended, the physical layer is switched from recessive bus states to the physical layer for bus states L0 and L1 in order to transmit a message 45 between the subscriber stations 100 and 10N. The switching between the operating modes of the transmit / receive devices 12 and 22 occurs at the beginning and end of the frame in CAN XL light Extended. The communication control units 11 and 21 signal their associated transmit / receive devices 12 and 22, via pulse-width modulation using the transmit signal TxD, that a switch is required.

[0078] Bit AH1 is followed by bit AL1 (logic 0) and bit AH2 (logic 1). The two bits DAH and AH1 ensure that all participating stations 100, 101, up to 10N see a recessive level significantly more than one arbitration bit time before the edge at the beginning of bit AL1 (logic 0). This guarantees reliable synchronization for the participating stations of bus system 1.

[0079] In the frame termination field 457, the acknowledgment field (ACK) follows the DAS field sequence. The acknowledgment field contains bits for confirming or rejecting the successful reception of frame 450. With CAN XL light Extended, a receiving station (100, ..., 10N) does not send a transmission acknowledgment (ACK bit) with a logic 0 value, which indicates successful reception. Instead, a receiving station always sends the ACK bit as a logic 1.

[0080] Following the frame termination field 457, the frame end field (EOF = End of Frame) follows in frame 450, as in CAN FD according to ISO11898-1:2015.

[0081] Following the end-of-frame (EOF) in frame 450 is an inter-frame space (IFS), which is Fig. The interframe space (IFS) is not shown. This interframe space is configured according to ISO 11898-1:2015 in CAN FD. The interframe space (IFS) has a minimum of 3 bits.

[0082] The following applies to CAN XL. - Unlike CAN FD, the frame identifier ID 450 in CAN XL is called "Priority ID". Unlike CAN FD, CAN XL can send the RRS bit as either a (logical) 0 or a (logical) 1. With CAN FD, the RRS bit is always sent as a logical 0.

[0083] Fig.Figure 3 shows the basic structure of the subscriber station 100 with the communication control unit 11, the transmit / receive unit 12, and the synchronization module 15, which is part of the communication control unit 11. Also shown is the operating mode signaling module 18, which is at least partially part of the communication control unit 11. Furthermore, the operating mode switching module 19, which is at least partially part of the transmit / receive unit 12, is also shown.

[0084] According to Fig.In addition to the communication control unit 11 and the transceiver 12, the subscriber station 100 (Commander) has a microcontroller 13, to which the communication control unit 11 is assigned, and a system ASIC 16 (ASIC = Application-Specific Integrated Circuit). The system ASIC 16 can alternatively be a system base chip (SBC) on which several functions necessary for an electronic assembly of the subscriber station 100 are combined. The system ASIC 16 has, in particular, 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 windshield washer system and / or a driver assistance system, etc.For example, the windshield washer system uses data from a rain sensor and / or wind sensor and / or speed sensor and / or light sensor to control the movement of at least one windshield wiper (actuator) and / or to switch a warning light (actuator) on or off. However, the application is not limited to a windshield washer system or parts thereof.

[0085] In addition to the transceiver 12, the system ASIC 16 incorporates a power supply unit 17, which provides electrical power to the transceiver 12. The power supply unit 17 typically provides a CAN_Supply (VCC) voltage of 5 V. However, depending on requirements, the power supply unit 17 can provide a different voltage with a different value. Additionally or alternatively, the power supply unit 17 can be configured as a current source.

[0086] To communicate with one of the participant stations 101 ... 10N, the communication control unit 11 creates a frame 450 in which a bit rate switch is entered in the fields ADS, DAS. Fig. 2 can be performed as described above, and / or evaluates such a frame 450. For this purpose, a standard CAN-XL communication control unit according to ISO / DIS11898-1:2024 can be used for the device 11, which has the additional functions as described above or below. This allows a data bit rate of up to 20 Mbit / s to be achieved in the data phase 452. With the communication control unit 11 as a CAN-XL-Light-Extended-Commander, the bit rate switching can be enabled or disabled. Disabled means that the user sets the same bit rate for the first communication phase (arbitration phase) 451 and the second communication phase (data phase) 452. The bit rate can also reach up to 20 Mbit / s in this case.

[0087] According to Fig. The synchronization module 15 has a synchronization block 151, optionally a configuration block 152, optionally an evaluation block 153, and a switching block 154. In the optional configuration block 152, a value for at least one synchronization configuration bit 1521 can be stored. The synchronization block 151 can be the bit-timing control unit (BTL) of the communication control unit 11.

[0088] The synchronization module 15, in particular the evaluation block 153 and the switching block 154, can be implemented at least partially as software.

[0089] Synchronization block 151 has a synchronization function described in ISO / DIS11898-2:2024. However, this synchronization function can be switched on and off as needed, as described in more detail below.

[0090] The transceiver 12 has a transmitter module 121 and a receiver module 122. Although the following text refers to the transceiver 12, it is alternatively possible to provide the receiver module 122 in a separate unit external to the transmitter module 121. The transmitter module 121 and the receiver module 122 can be configured as in a conventional CAN-SIC-XL transceiver 12, which has the additional functions described above or below. In particular, the transmitter module 121 can include at least one operational amplifier and / or one transistor. The receiver module 122 can also include at least one operational amplifier and / or one transistor.

[0091] The transceiver 12 is connected to bus 40, specifically its first bus wire 41 for CAN_H and its second bus wire 42 for CAN_L. The power supply for the power supply unit 17, which provides electrical energy, in particular the CAN supply voltage, to the first and second bus wires 41 and 42, is provided via at least one terminal 43. The connection to ground or CAN_GND is made via a terminal 44. The first and second bus wires 41 and 42 are terminated with a terminating resistor 49.

[0092] The first and second bus wires 41, 42 are connected in the transmit / receive unit 12 not only to the transmit module 121, which is also called transmitter, but also to the receive module 122, which is also called receiver, even if the connection in Fig. Figure 3 is not shown for the sake of simplicity.

[0093] In the operation of bus system 1, the transmitter module 121 can be used by Fig.3 a transmit signal TxD of the communication control unit 11, for example the transmit signal TxD from Fig. 4, convert serially into corresponding signals CAN_H, CAN_L for CAN XL or its variations for the bus wires 41, 42 and send these signals to the bus 40 at the connections for CAN_H and CAN_L.

[0094] The communication control unit 11 sends the transmit signal TxD from Fig. 4, if communication is possible in bus system 1 according to XL light, or a transmit signal TxD1 from Fig. 8, if communication is possible in bus system 1 according to XL light Extended, over time t (serially) via the TXD connection to the transmitter module 121, as in Fig. 3 shown. As an example in Fig. As shown in Figure 4, the transmitted signal TxD has the voltage states H (High) and L (Low) with a corresponding voltage U. On the right side of Fig.4. The signal TxD is pulse-width modulated with a first symbol PWM1 and a second symbol PWM2 in the transmitted signal TXD. The second symbol PWM2 differs from the first PWM symbol PWM2, as shown, for example, in Fig. 4 shown.

[0095] According to the example of Fig. 5. The participant station 100 can be configured for communication according to CAN XL light, for a frame 450 of Fig. 2. During the arbitration phase 451, signals CAN_H and CAN_L are generated, which have the dominant and recessive bus levels 401 and 402 according to a first physical layer 451_P, as known from CAN XL. Furthermore, the subscriber station 100 can be configured for communication according to CAN XL light, for frame 450 of Fig. 2 in the data phase 452 to generate the bus levels L0, L1 according to a second physical layer 452_P, as known from CAN XL.

[0096] Fig.Figure 5 on the left shows that in the first communication phase 451 of CAN XL light, the receiving station 100 can send signals CAN_H and CAN_L over time t to bus 40, each with a first bit time t_bt1. The signals CAN_H and CAN_L are serial signals and alternately have at least one dominant state 401, in which, with a supply voltage VCC = 5 V, VCAN_H = 3.5 V and VCAN_L = 1.5 V, or at least one recessive state 402, in which 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 LOW (LOW = low). Fig. 5) A recessive state 402 (rec) is generated, or occurs in phase 451 during NRZ encoding of the transmit signal TXD, when TXD = 1 or HI (HIGH) applies ( Fig. 5).

[0097] As on the right side of Fig.As shown in Figure 5, the state L0 (VCAN_H = 3.0 V, VCAN_L = 2.0 V at VCC = 5 V) is driven by the pulse-width modulation (PWM encoding) of the transmit signal TXD for the first PWM symbol PWM1 in the transmit signal TXD. The state L1 (VCAN_H = 2.0 V and VCAN_L = 3.0 V at VCC = 5 V) is driven by the pulse-width modulation (PWM encoding) of the transmit signal TXD for the second PWM symbol PWM2. The states L0 and L1 have a bit time t_bt2, which is shorter than the bit time t_bt1.

[0098] Fig.Figure 6 shows a differential signal VDIFF = CAN_H - CAN_L, which is generated on bus 40. The individual bits of the VDIFF signal with bit time t_bt1 can be detected by the transmit / receive devices 12 and 22 during arbitration phase 451 with a receive threshold T1 of, for example, 0.7 V, which lies within the range TH_T1, as known from CAN XL. With an optional receive threshold T2 of, for example, -0.3 V, which can be activated only during arbitration phase 451 and lies within the range TH_T2, the transmit / receive devices 12 and 22 detect whether the bus levels L0 and L1 are being transmitted on bus 40 or not. With the optional receive threshold T2, a subscriber station 100, which is switched to the operating mode of the arbitration phase 451, detects whether bus levels L0, L1 of the data phase 452 are present on the bus 40.In the communication phase (data phase) 452, the transmitting / receiving devices 12, 22 recognize the individual bits of the signal VDIFF with a receive threshold T3 of, for example, 0.0 V, which lies in a range of TH_T3, as is known from CAN XL.

[0099] The sequence of states H, L of the transmitted signal TxD from Fig. 4 and the resulting states 401, 402 for the signals CAN_H, CAN_L in Fig. 5 and the resulting voltage VDIFF curve of Fig. Figure 6 serves only to illustrate the function of participant station 100. The sequence of data states for bus states 401 and 402 can be selected as needed.

[0100] The receiver module 122 generates CAN_H and CAN_L signals from bus 40, which are then used in Fig. 5 are shown, or the differential voltage VDIFF of Fig. 6. A receive signal RxD. For the generation of the digital receive signal RxD from Fig.7. The receiver module 122 uses the receive thresholds T1, T2, T3, as previously described. The receive signal RxD is in Fig. 7 without propagation delay. The receiving module 122 forwards this received signal RxD to the associated communication control unit 11, as shown in Fig. 3 shown.

[0101] The reception thresholds T1 and T2 are 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.

[0102] If the CAN XL light Extended-capable subscriber stations 100, 101, ..., 10N use the operating mode switching of the operating mode switching module 19 for their transmit / receive equipment 12, 22, then the transmitter of a frame 450 generates a transmit signal TxD1 according to Fig. 8, so that for a message 45, which is on a frame 450 of Fig. 2 based, instead of the signals from Fig. 5 and Fig. 6 on bus 40 the signals from Fig. 9 and Fig. 10 are generated. The propagation delays of the signals from Fig. 5 to Fig. 7 compared to the transmitted signal from Fig. Four are omitted from the figures for simplicity. Furthermore, the propagation delay of the signals is... Fig. 9 and Fig. 10 compared to the transmitted signal from Fig. 8 is not shown in the figures for the sake of simplicity.

[0103] Accordingly, the participant stations 100 ... 10N are designed for communication according to CAN XL light Extended, as shown below for participant stations 100 (Commander) and as an example for participant station 101 (Responder). Table 1: Communication status of participant stations 100 ... 10N in CAN XL light Extended Communication status Participant station 100 Participant station 101 Action status, operating mode Driven bus condition Action status, operating mode Driven bus condition No communication Received (SIC) 402 (Rec) Received (SIC) 402 (Rec) Participant station 100 is sending (Phase 451) Send(FAST_TX) L0, L1 Received (FAST_RX) 402 (Rec) Participant station 101 is transmitting (Phase 451) Received (FAST_RX) 402 (Rec) Send(FAST_TX) L0, L1

[0104] Thus, only in FAST_TX mode are there symmetrical bus states L0, L1. In FAST_RX mode, each of the participating stations 101 ...10N transmits at high impedance (REC), but each of the participating stations 101 ...10N adjusts its receive threshold to 0V in FAST_RX mode in order to be able to decode the bus states L0, L1.

[0105] As in Fig. As shown in Figure 9, the transceivers 12 and 22 use the first operating mode SIC of a CAN XL SIC subscriber station when there is no communication or idle on bus 40. In this mode, the transceivers 12 and 22 use a physical layer 4510_P, in which only recessive states 402 (Rec) are generated on bus 40. Furthermore, the transceivers 12 and 22 use the second physical layer 452_P as a transmitter for the entire frame 450 to send a transmit signal TxD ( Fig.8) to send the CAN_H and CAN_L signals to bus 40 over time t. For Physical Layer 452_P, there are two operating modes, namely FAST_TX and FAST RX, as described previously.

[0106] In CAN XL light Extended communication in bus system 1, the transmit / receive devices 12, 22 optionally use the receive threshold T1 when not communicating, i.e., in SIC operating mode. the receive threshold T2. As receivers of a frame 450, i.e. in FAST_RX mode, the transmit / receive devices 12, 22 use only The third reception threshold T3 is approximately 0.0 V. The third reception threshold T3 A voltage of approximately 0.0 V is therefore present when there is no communication on bus 40. switched off. By deactivating the third receive threshold T3, recessive states 402 (Rec) on bus 40 are prevented from leading to the detection of incorrect states on bus 40.

[0107] Even if this is in Fig. 9 and Fig. As not shown in Figure 10, the bits of the CAN_H and CAN_L signals in communication phase 452 of frame 450 can be transmitted at least temporarily slower than with the bit time t_bt2, as described previously. Thus, in CAN XL for frame 450, the CAN_H and CAN_L signals differ from the conventional CAN_H and CAN_L signals in Classical CAN, at least in their bus states L0, L1, and optionally also in their faster bit rate, during communication phase 452.

[0108] Each of the participating stations 100, 101, ..., 10N can send and / or receive. In the following example, it is simply assumed that participating stations 101, ..., 10N are receivers of the currently transmitted frame 450.

[0109] Assuming that the subscriber station 100 (Commander) sends a frame 450 to the bus 450, the communication control unit 11, in particular the operating mode signaling module 18, transmits from the SOF bit of the transmit signal TxD1 onwards. Fig. 8. A signal is sent to the transmit-receive device 12 using a pulse-width modulated symbol P. The symbol P can be defined as PWM symbol PWM1 or PWM symbol PWM2. Alternatively, another PWM symbol can be used. The symbol P signals to the transmit-receive device 12 that it must switch its operating mode SIC, in which the bus state 402 (rec) is generated, to the operating mode FAST_TX in order to serially send the subsequent bits of frame 450 to bus 40.

[0110] Thus, the transmit-receive device 12 switches the Physical Layer 4510_P, in which the bus state 402 (rec) is generated, to the Physical Layer 452_P.

[0111] Vienna Fig.As shown in Figure 9, the transmitter module 121 of the subscriber station 100 then generates a signal from the SOF bit onwards, switched to the second operating mode (FAST_TX) and depending on the transmit signal TxD1 from Fig. 8, successively and thus serially, the states L0 or L1 with the physical layer 452_P for the signals CAN_H, CAN_L on bus 40. The signals CAN_H, CAN_L on bus 40 are delayed by the time that the transmitter module 121 needs to transmit the signal TxD1 from Fig. 8 to decode and send to bus 40. Fig. Figure 10 shows the resulting differential signal VDIFF on bus 40.

[0112] For CAN XL light Extended, the transmitter module 121 of the participant station 100 also generates the SOF bit as a PWM symbol for the bus state L0, as shown in Fig. 8 and Fig.9, and sends to the transceiver 12. The PWM symbol is decoded by the transceiver 12, specifically its operating mode decoding module 19. Based on the PWM symbol for bus state L0, the transceiver 12 switches to FAST_TX operating mode. Previously, the transceiver 12 is switched to SIC operating mode, in which it always sends the recessive bus state. Because decoding a PWM symbol is only possible at the end of the symbol, the transceiver 12 sends the bus states L0 / L1 with a delay equal to the length of a PWM symbol. Thus, in Fig. 9 the SOF bit by the length of one PWM symbol further to the right than in Fig. 8.

[0113] In the present example, participant station 100 (Commander) is the sender of frame 450. Consequently, participant station 101 is the receiver of frame 450, and therefore not a sender. The same applies to the responder participant stations 102...10N. Therefore, upon receiving a bus state L0 (alternatively L1), the transmit / receive devices 22 of participant stations 101...10N switch according to the signal from Fig. 10 due to the detection of one of the receive thresholds T1 (alternatively T2) their physical layer for the communication phase 452, namely from the physical layer 4510_P of the first operating mode SIC to the physical layer 452_P of the third operating mode FAST_RX of the transmit / receive device 22.

[0114] At the end of frame 450, the following applies. At the end of frame 450, the communication control unit 11, more precisely its operating mode signaling module 18, stops the PWM encoding and no longer transmits PWM symbols. If the transmit / receive unit 12 detects at its TXD connection for a transmit signal TxD1 that the PWM encoding has stopped, the transmit / receive unit 12 switches from transmitting (operating mode FAST_TX) signals with Physical Layer 452_P to operating mode SIC, in which Physical Layer 4510_P is used. The transmit / receive unit 12 is designed such that in operating mode SIC only the receive threshold T1 (alternatively T2) is active. Consequently, the receive threshold T3 = approximately 0.0 V is deactivated or switched off.

[0115] At the end of frame 450, the communication control unit 21, more precisely its operating mode signaling module 28, stops the PWM encoding and no longer transmits PWM symbols. When the transmit / receive unit 22 detects that the PWM encoding has stopped, it switches its receive mode (FAST_RX) to the first operating mode (SIC). This switchover means that the transmit / receive unit 22 deactivates or turns off its receive threshold T3 = approximately 0.0 V and activates T2.

[0116] Upon receiving the corresponding signals from bus 40, each transmit / receive device 12 generates the associated receive signal RxD, as shown in Fig. 7 shown and previously described.

[0117] The substation 100 is thus configured like a standard CAN-XL substation with the additional functions described above. The user ensures, through the configuration of the data field and / or by selecting the identifiers (IDs) of substation 100 (Commander) and substations 101...10N, that substation 100 operates as a CAN XL Light Extended Commander and substations 101...10N as CAN XL Light Extended Responders according to the polling principle. Accordingly, substation 100 (Commander) may send messages 45 to each of the substations 101...10N (Responders). Substation 100 (Commander) encodes in message 45 whether the responder should reply or not. Only with a prior request may the responder send a message, and for this purpose use the certain time window in which up to N of the participating stations 101...10N (responders) can send a message 45 one after the other.

[0118] Optionally, participant station 100 (Commander) can proceed as follows.

[0119] In the operation of bus system 1, the subscriber station 100 (commander), more precisely the communication control unit 11, performs bus monitoring. According to ISO 11898-1:2015, the subscriber station 100, in particular the communication control unit 11, compares its data according to a frame 450 and a transmit signal TxD ( Fig. 5 or Fig. 8), self-sent bits at a sampling point t_A (sample point) with the bits observed on bus 40 according to the received signal RxD ( Fig. 7) A difference is considered an error, except in the case of arbitration and the ACK bit.

[0120] However, according to the pre-configured software settings, station 100 (Commander), specifically the communication control unit 11, deactivates bus monitoring for short bit times t_bt1, t_bt2 when station 100 (Commander) is the sender of message 45. These short bit times can occur during the arbitration phase 451 and / or the data phase 452. Such short bit times occur at bit rates above 1 Mbit / s, where the so-called loop delay of station 100 (CAN node) reaches half a bit time t_bt1, t_bt2 or more. The loop delay is the time it takes for station 100 to internally receive the bit of the transmit signal TxD, sent via the TXD port, as a received signal RxD.

[0121] In addition, the participant station 100 (Commander), more precisely the communication control unit 11, performs a synchronization function for all frames 450 in the operation of the bus system 1 with the synchronization block 151, which the participant station 100 (Commander) receives from one of the responders 101...10N.

[0122] Synchronization block 151 monitors the transitions from recessive to dominant or vice versa, i.e., a change between states 401, 402 or 402, 401 in Fig. 6 or Fig. 7 or Fig. 9 and Fig. 10. The synchronization block 151 synchronizes the position of the sample point t_A (sample point) within a bit time t_bt1 based on the observed edges ( Fig. 5 and Fig.6) A receiver synchronizes itself to the sender of a frame 450. Ideally, if an edge occurs at the beginning of a bit time t_bt1, t_bt2, no synchronization is necessary, as edge transitions can occur at the beginning of a bit time. If an edge occurs between the beginning of a bit time t_bt1, t_bt2 and the sample point t_A, it is called a late edge. This triggers synchronization, lengthening the current bit time t_bt1, t_bt2. If an edge occurs between the sample point t_A and the end of a bit time t_bt1, t_bt2, it is called an early edge. This triggers synchronization, shortening the current bit time t_bt1, t_bt2.

[0123] According to ISO 11898-1:2015, the transmitters of a frame 450 also synchronize. However, a restriction applies: a receiving station 100 transmitting a dominant bit does not synchronize to late edges. This is because, due to the loop delay, the transmitter sees all its own transmitted bits as late. Therefore, synchronizing to these late edges, which were transmitted by the receiving station itself, would lengthen these bits and distort the bit rate. The permitted synchronization to early edges stabilizes the CAN arbitration at the beginning of the frame 450. This is particularly necessary when arbitration takes place. No arbitration occurs with CAN XL light Extended.

[0124] The synchronization function is described in more detail in ISO 11898-1:2015.

[0125] However, with the synchronization module 15, the synchronization function of the synchronization block 151 can be switched on and off as required, as described below.

[0126] Evaluation block 153 is configured to evaluate the synchronization configuration bit 1521 in configuration block 152. Synchronization configuration bit 1521 is set when the receiving station 100 (commander), specifically the communication control unit 11, is to send frame 450 with a bit time t_bt1 of the first communication phase 451 of CAN XL that corresponds to a bit rate greater than a predetermined bit rate. The predetermined bit rate is, in particular, greater than 1 Mbit / s.

[0127] If the evaluation of evaluation block 153 shows that the synchronization configuration bit 1521 is set, evaluation block 153 checks whether the participant station 100 (commander), more precisely the communication control unit 11, should (currently) act as a sender, i.e., send a frame 450 to a responder on bus 40. The synchronization configuration bit 1521 is set, for example, together with the bit rate configuration, either via software or hardwired. During operation of bus system 1, the configuration bit 1521 is then constant.

[0128] If the evaluation of evaluation block 153 indicates that the participant station 100 (commander), more precisely the communication control unit 11, is to act as a sender and send a frame 450 to a responder on bus 40, evaluation block 151 instructs switching block 154 to switch off synchronization block 151. Switching block 154 thus switches off synchronization block 151 and therefore its previously described synchronization function for all bits of the frame 450 to be sent by participant station 100 as commander on bus 40, up to the last bit of the end-of-flight (EOF) field.

[0129] Disabling synchronization block 151 prevents the transmitter from synchronizing to its own transmitted edges, which it does not detect within the transmitted bit but in one of the subsequent bit times. Synchronization can be disabled because arbitration is no longer possible at this bit rate t_b1, which exceeds 1 Mbit / s.

[0130] After the last bit of the end-of-flight (EOF) field of the transmitted frame, switching block 154 switches. Fig. 4. The synchronization block 151 and thus its previously described synchronization function are reactivated.

[0131] Furthermore, at participant station 100 (Commander), the requirement to send an acknowledgment (ACK bit or ACK response) for a message 45 from a responder (participant station 101 ... 10N) can be deactivated. Additionally, at participant station 100 (Commander), the requirement to receive an acknowledgment (ACK bit or ACK response) for a message 45 sent by it to a responder (participant station 101 ... 10N) can be deactivated.

[0132] According to Fig.In addition to the communication control unit 21 and the transmit / receive unit 22, the responder subscriber station 101 has a simple control unit (FSM) or optionally a microcontroller 23, to which the communication control unit 21 is assigned, and a system ASIC 26 (ASIC = Application-Specific Integrated Circuit), which can alternatively be a system base chip (SBC) on which several functions necessary for an electronic assembly of the subscriber station 101 are combined. The system ASIC 26 has, in particular, an application 261, which can be designed as a computer program (app). Such an application is a technical application 261.

[0133] Application 261, for example, is a control for a sensor, transmitter, actuator, or the like, which is controlled by application 161 ( Fig. 3) is controlled by the Commander participant station 100 or is intended to provide data for application 161.

[0134] The responders have little or no local processing power and can perform simple functions, such as switching an LED on / off or controlling the LED color, as described previously. A responder only sends a frame 450 when requested to do so by the commander. Thus, after receiving a request from the commander, the responder CAN subscriber stations (responders) send their function information, such as a sensor value, to the commander CAN subscriber station (commander) via a CAN XL message.

[0135] According to Fig.In addition to the transmitter / receiver 22, the system ASIC 26 incorporates a power supply unit 27, which provides electrical power to the transmitter / receiver 22. The power supply unit 27 typically provides a CAN_Supply voltage of 5 V. However, depending on requirements, the power supply unit 27 can provide a different voltage with a different value. Additionally or alternatively, the power supply unit 27 can be configured as a current source.

[0136] The communication control unit 21 creates a frame 450 in which a bit rate switching or bit rate change can take place, as in relation to Fig.2 describes, and / or evaluates such a frame 450 based on the frame 450 received by the Commander participant station 100. The communication control unit 21 acts as a CAN-XL-Light-Extended responder. The units 21 and 22 can only send such a frame 450 to bus 40 upon request from the Commander participant station 100 (polling).

[0137] As previously described, the operating mode signaling module 28 signals to the transmitting module 221 by means of the PWM symbol P at the TXD terminal or in a TxD signal that the bus state rec should be changed to the bus levels L0, L1 according to the states L, H or 0, 1 in the TxD signal when a message 45 is to be sent.

[0138] Furthermore, the operating mode switching module 29 activates the receive threshold T3 on the receive module 222 when the receive threshold T1 (approximately +0.6 V) is exceeded. The operating mode switching module 29 deactivates the receive threshold T3 again, particularly in the DAS field or at the end of frame 450 (after the EOF (7 bit)), as described previously. The absence of PWM encoding at the TXD terminal indicates that the receive threshold T3 needs to be deactivated.

[0139] In the operation of bus system 1, responder station 101 performs the following procedure when responder station 101 is currently a receiver. However, each of the subscriber stations 100 ... 10N (commander and responder) is configured in the same way and behaves in the same way as a receiver, as described below.

[0140] A rising edge on bus 40, where the receive threshold T1 (approximately 0.7 V or approximately 0.6 V) is exceeded, puts the transmit / receive unit 22 into FAST_RX mode. In FAST_RX mode, the operating mode switching module 29 activates the receive threshold T3 (approximately 0.0 V) on the receive module 222.

[0141] The transmit / receive device 22 passes the bus signal, which corresponds to a transmit signal TxD of logic 0 due to the start bit (SOF), to the RXD terminal and so on to the communication control device 21.

[0142] Based on the transition from 1 to 0 of the SOF bit at the RXD terminal, the communication control unit 21 recognizes that it is to receive something.

[0143] Therefore, the communication control unit 21 instructs the operating mode signaling module 29 to signal the transmit / receive unit 22 (transceiver) to switch to FAST_RX operating mode. This signaling ensures that the transmit / receive unit 22 (transceiver) remains in FAST_RX operating mode for as long as the signaling continues.

[0144] At the end of frame 450, which is known to the communication control unit 21, the communication control unit 21 switches off the operating mode signaling. Therefore, the transmit / receive unit 22 (transceiver) switches to or enters SIC operating mode.

[0145] The transmitter module 221 from Fig. 10 is otherwise constructed in the same way as previously for the transmitter module 121 from Fig. 3 described.

[0146] The synchronization module 25 of Fig.10 has a synchronization block 251, a configuration block 252, an evaluation block 253 and a switching block 254. At least one configuration bit 2521, 2522 is stored in the configuration block 252.

[0147] The synchronization module 25 can also deactivate synchronization for frames 450 or messages 45 sent by the subscriber station 101, as previously described above. Fig. Section 3 describes the synchronization module 15 for frame 450. Accordingly, the synchronization module 25 always disables synchronization for frames 450 or messages 45 sent by the subscriber station 101 at high bit rates. High bit rates are, for example, greater than 1 Mbit / s.

[0148] Unlike the synchronization module 15 from Fig. 3 is the synchronization module 25 of Fig.Option 10 allows the synchronization of frames 450 or messages 45 sent by the subscriber station 101 to be deactivated in the associated responder, even at low bit rates. For this purpose, an additional configuration bit 2522 can be set, for example. Low bit rates are, for instance, less than or equal to 1 Mbit / s. This deactivation has no significant impact on communication between the commander subscriber station 100 and the respective responder subscriber station 101 ... 10N.

[0149] This makes it possible to select that the synchronization module 25 of Fig. 11 is optionally configured to deactivate its synchronization function for frames 450 or messages 45 sent by the subscriber station 101 at both low and high bit rates. In other words, it is selectable that the synchronization module 25 of Fig.10 is designed to disable its synchronization function for frames 450 or messages 45 sent by the subscriber station 101, regardless of the bit rate.

[0150] The participant stations 101 ... 10N can do without these synchronizations because no arbitration takes place with CAN XL Light and CAN XL Light Extended or when communicating with the Commander participant station 100, and no ACK bit is sent at higher bit rates.

[0151] The synchronization module 25 is otherwise structured in the same way as previously described for the synchronization module 15.

[0152] The synchronization modules 15 and 25 thus ensure that communication with CAN XL Light is also possible at bit rates greater than or equal to 1 Mbit / s.

[0153] The participant stations 101 ... 10N (responders) thus have a CAN-XL Light Protocol controller, which is additionally or alternatively designed for the previously described functions of CAN XL Light Extended. The CAN-XL implementation of the communication control unit 21 has been adapted for this purpose. The adaptations aim to simplify or reduce the functionality in order to lower resource requirements. Among other things, the following adaptations are included.

[0154] Bit monitoring during the transmission of message 45 is either not present or disabled in the communication control unit 21. This is possible because CAN XL light and CAN XL light Extended do not require arbitration and cannot send error frames. The lack of arbitration allows the sampling point t_A to be determined according to... Fig.The value can be moved 10 further towards the center of the bit, thus allowing for greater tolerance in the accuracy of the CAN clock. Furthermore, the "Transmitter Delay Compensation" function can also be optimized away or omitted, as it is only used for bit monitoring in the data phase during the transmission of a frame 450, and bit monitoring is no longer required.

[0155] Furthermore, the communication control unit 21 does not support or disable signaling via error frames and overload frames. This is possible because immediate error signaling is not required for CAN XL Light and CAN XL Light Extended.

[0156] Furthermore, the communication control unit 21 does not perform automatic retransmission. Since CAN XL Light and CAN XL Light Extended cannot resolve collisions on bus 40 using arbitration, a CAN XL Light subscriber station 101...10N (responder) must not automatically retransmit a message.

[0157] Furthermore, the fault confinement function should be omitted in the communication control unit 21. CAN XL, CAN FD, and Classical CAN (CC) stipulate that a device connected to the CAN bus is automatically shut down if it detects too many communication errors. This prevents a faulty device from interfering with the communication of other devices.

[0158] Since the responder in CAN XL Light and CAN XL light Extended only sends a frame 450 when requested to do so by the commander via frame 450, there is no need for automatic node shutdown.

[0159] As well as the Commander's communication control unit 11 according to the description of Fig. The communication control unit 21 of the responder can also be configured for high bit rates, namely greater than 1 Mbit / s, in the arbitration phase 451. - not to send an ACK bit if facility 21 has correctly received a message 45, and - no synchronization to the seen received signal RxD ( Fig. 7) to be carried out while sending a frame 450.

[0160] In contrast to the communication control unit 11 of the Commander, the communication control unit 21 of the Responder is designed to only support or send and / or receive CAN frames in XLFF (XL Base Frame Format) format.

[0161] Thus, a CAN XL light Extended Responder can optionally be configured to send and receive frames only in one format (XL), namely frame 450 according to Fig. 2.

[0162] By limiting the system to a single frame format, the implementation effort of the CAN XL light Extended Responder, in particular its communication control unit 21, is significantly reduced.

[0163] According to a second embodiment, the transmitting / receiving devices 12, 22 are designed to use different levels than the L0 and L1 levels during the communication on bus 40 described above according to CAN XL light Extended. Fig.10 to use. Such other levels could be, for example, L0 and L1 levels according to the 10BASE-T1S standard.

[0164] Accordingly, the transmitter / receiver devices 12 and 22 are configured to generate the differential signals CAN_H and CAN_L on bus 40 such that the differential voltage VDIFF for a bus state L0_10BASE is approximately +0.5 V. Furthermore, the transmitter / receiver devices 12 and 22 are configured to generate the differential signals CAN_H and CAN_L on bus 40 such that the differential voltage VDIFF for a bus state L1_10BASE is approximately -0.5 V.

[0165] The differential voltage VDIFF for the bus state Rec remains unchanged at 0.0 V.

[0166] Even when using the bus states L0_10BASE, L1_10BASE, the frame 450 of Fig. 2 can be used for communication on bus 40. Alternatively, any other frame format can be used.

[0167] Otherwise, the same applies as described in relation to the first embodiment.

[0168] According to a third embodiment, the communication control devices 11, 21 are set so that no switching of the bit rates is carried out in the frame 450 for CAN XL light Extended.

[0169] More precisely, the bit rate of the communication control devices 11, 21 is set: 0 Mbit / s <Arbitrationsbitrate t_b1=Datenbitrate t_b2<=20 Mbit / s. so that applies Bit time t_bt1 = Bit time t_bt2

[0170] This saves additional space on ASIC 26 of the responder, and potentially also on ASIC 16 of the commander, if the subscriber station 100 does not otherwise require the bit rate switching function. Furthermore, clock recovery from the CAN bit stream is simplified, allowing a crystal oscillator in the responder to be eliminated. This further reduces the responder's cost. Eliminating a crystal oscillator is also possible in the preceding embodiments.

[0171] Furthermore, not only the communication control units 21, but also the communication control units 11 can be configured not to perform arbitration. The subscriber station 100 (Commander) controls the communication in such a way as to avoid access conflicts on bus 40.

[0172] This method also allows for a cost-effective connection of responders to differential bus systems, in particular a CAN bus system or a 10BASE-T1 S system.

[0173] Otherwise, the same applies as described in relation to the first embodiment.

[0174] All previously described configurations of the participant stations 100, 101 ... 10N, the bus system 1, and the method implemented therein can be used individually or in any possible combination. In particular, all features of the previously described embodiments and / or their modifications can be combined as desired. Additionally or alternatively, the following modifications are particularly conceivable.

[0175] In particular, according to the embodiments, bus system 1 can be a communication network in which data can be transmitted serially at two different bit rates. It must be ensured in bus system 1 that, at least for certain periods of time, exclusive, collision-free access of a participant station 100, 101 ... 10N to a common channel is guaranteed.

[0176] The number and arrangement of the participant stations 100, 101 ... 10N in the bus system 1 of the exemplary embodiments is arbitrary. It is possible for one or more participant stations 100 to be present in the bus system 1. It is also possible for more than one participant station 100 to be present in the bus system 1, each of which is assigned at least one participant station 101 ... 10N, as described above.

[0177] It is conceivable that at subscriber station 100, module 15 is arranged separately from the communication control unit 11. It is conceivable that at at least one of the subscriber stations 101 ... 10N, module 25 is arranged separately from the communication control unit 21.

[0178] It is conceivable that at subscriber station 100, module 18 is arranged separately from the communication control unit 11. It is conceivable that at at least one of the subscriber stations 101 ... 10N, module 28 is arranged separately from the communication control unit 21.

[0179] It is conceivable that at subscriber station 100, module 19 is arranged separately from the transmit / receive device 12. It is also conceivable that at at least one of the subscriber stations 101 ... 10N, module 29 is arranged separately from the transmit / receive device 22. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited non-patent literature

[0000] ISO11898-1:2015 [0003, 0050, 0119, 0124] ISO / DIS11898-1:2024 [0004, 0050]

Claims

[1] Transmit / receive device (12; 22) for a commander subscriber station (100) or a responder subscriber station (101; ...; 10N) of a serial bus system (1), with a transmitting module (121; 221) for sending a digital transmit signal (TxD) based on a frame (450) for a message (45) to be sent via the bus (40), as a differential signal (CAN_H, CAN_L) to a bus (40) of the bus system (1), a receiving module (122; 222) for receiving a differential signal (VDIFF) from the bus (40) and for generating a digital receive signal (RxD) from the differential signal (VDIFF) received from the bus (40) and for forwarding the digital receive signal (RxD) to a communication control unit (11; 21) for evaluating the digital receive signal (RxD) based on a predetermined frame (450) for a message (45) from the bus (40), and an operating mode switching module (19; 29) for switching the transmit module (121; 221) and the receive module (122; 222) between messages (45) on the bus (40) into a first operating mode (SIC) or for switching the transmit module (121; 221) and the receive module (122; 222) for sending or receiving a message (45) into a second or third operating mode (FAST_TX; FAST_RX), wherein the operating mode switching module (19; 29) is configured to switch the transmit module (121; 221) and the receive module (122; 222) from the first operating mode (SIC) to the third operating mode (FAST_RX) to receive a message (45) from the bus (40) when the operating mode switching module (19; 29) has received an edge from the bus (40). [2] Transmitting / receiving device (12; 22) according to claim 1, wherein the operating mode switching module (19; 29) is configured to switch the transmitting module (121; 221) and the receiving module (122; 222) from the third operating mode (FAST_RX) to the first operating mode (SIC) when the operating mode switching module (19; 29) has received a predetermined signaling from the communication control device (11; 21). [3] Transmitting / receiving device (12; 22) according to claim 1 or 2, wherein the transmit / receive device (12; 22) is configured to use a first physical layer (4510_P) in the first operating mode (SIC) to generate only one first bus state (402) on the bus (40), and wherein the transmit / receive device (12; 22) is configured to use a second physical layer (452_P) in the second and third operating modes (FAST_TX; FAST_RX), which differs from the first physical layer (4510_P), to generate a second and third bus state (402) as symmetrical bus states (L0, L1) for the differential signals (CAN_H, CAN_L) on the bus (40). [4] Transmitting / receiving device (12; 22) according to claim 3, wherein the only one bus state (Rec) for differential signals (CAN_H, CAN_L) on the bus (40) in the first operating mode (SIC) differs from each of the symmetrical bus states (L0, L1) for differential signals (CAN_H, CAN_L) on the bus (40) for which the transmitting / receiving device (22) is configured in the two other operating modes (FAST_TX, FAST_RX). [5] Transmitting / receiving device (12; 22) according to one of the preceding claims, wherein the transmitting / receiving device (22) is configured to switch on a predetermined receive threshold (T3) to generate a digital receive signal (RxD) from the differential signal (VDIFF) received by the bus (40) when switching from the first operating mode (SIC) to the third operating mode (FAST_RX), but to switch off the predetermined receive threshold (T3) when switching from the third operating mode (FAST_RX) to the first operating mode (SIC). [6] Responder subscriber station (101; 102; ... 101N) for a serial bus system (1), with a communication control device (21) for controlling communication between the subscriber station (101; 102; ... 101N) and a commander subscriber station (100) of the bus system (1) and for evaluating at least one signal (VDIFF; RxD) received from a bus (40) of the bus system (1) based on a predetermined frame (450) for a message (45) from the bus (40), and a transmitting / receiving device (22) according to one of the preceding claims, wherein the communication control device (21) is configured to signal to the transmitting / receiving device (22) at each bit of the predetermined frame (450) which of the operating modes the transmitting / receiving device (22) is to be switched to. [7] Responder subscriber station (101; 102; ... 101N) according to claim 6, wherein the communication control device (21) is configured to send a message (45) via the bus (40) to the commander subscriber station (100) only when the commander subscriber station (100) has requested the responder subscriber station (101; 102; ... 101N) to do so by means of a send request. [8] Responder subscriber station (101; 102; ... 101N) according to claim 6 or 7, furthermore with an operating mode signaling module (28) for signaling which of three different operating modes (SIC, FAST_TX, FAST_RX) the transmit / receive device (22) is to be switched to, wherein the operating mode signaling module (28) is configured to signal a change of operating mode (SIC) at the beginning of the message (45) in the transmit signal (TxD) when the transmit / receive device (22) is to be switched to an operating mode (FAST_TX) for sending the message (45) to the bus (40), and wherein the operating mode signaling module (28) is designed to signal a change of operating mode (SIC) at the beginning of the message (45) when the transmit / receive device (22) is switched to an operating mode (FAST_RX) for receiving the message (45) from the bus (40). [9] Responder subscriber station (101; 102; ... 101N) according to one of claims 6 to 8, wherein the responder subscriber station (101; 102; ... 101N) is configured to use a CAN XL frame in the XLFF format as a predetermined frame (450). [10] Commander subscriber station (100) for a serial bus system (1), with a communication control device (11) for controlling communication between the subscriber station (100) and a responder subscriber station (101; 102; ... 101N) of the bus system (1) and for evaluating at least one signal (VDIFF; RxD) received from a bus (40) of the bus system (1) based on a predetermined frame (450) for a message (45) from the bus (40), and a transmitting / receiving device (12) according to one of the preceding claims, wherein the communication control device (11) is designed to signal to the transmitting / receiving device (12) at each bit of the predetermined frame (450) which of the operating modes the transmitting / receiving device (12) is to be switched to. [11] Commander subscriber station (100) according to claim 10, wherein the communication control device (12) is configured to request the responder subscriber station (101; 102; ... 101N) by means of a send request to send a message (45) via the bus (40) to the commander subscriber station (100). [12] Commander participant station (100) according to claim 10 or 11, furthermore with an operating mode signaling module (18) for signaling which of three different operating modes (SIC, FAST_TX, FAST_RX) the transmit / receive device (12) is to be switched to, wherein the operating mode signaling module (18) is configured to signal a change of operating mode (SIC) at the beginning of the message (45) in the transmit signal (TxD) when the transmit / receive device (12) is to be switched to an operating mode (FAST_TX) for sending the message (45) to the bus (40), and wherein the operating mode signaling module (18) is designed to signal a change of operating mode (SIC) at the beginning of the message (45) when the transmit / receive device (12) is switched to an operating mode (FAST_RX) for receiving the message (45) from the bus (40). [13] Bus system (1), with a bus (40), and at least two participant stations (100; 101...10N) which are connected to each other via the bus (40) in such a way that they can communicate serially with each other and of which one participant station is a commander participant station (100) according to one of claims 10 to 12 and at least one participant station is a responder participant station (101; 102; ... 101N) according to one of claims 6 to 9. [14] Method for communication in a serial bus system (1), wherein the method is carried out with a commander subscriber station (100) according to one of claims 10 to 12 and a responder subscriber station (101; 102; ... 101 N) according to one of claims 6 to 9. [15] Method according to claim 14, wherein in contrast to a CAN XL subscriber station the Commander subscriber station (100) and the Responder subscriber station (101 ... 101N) do not perform bit monitoring when sending a message (45), The commander subscriber station (100) does not send an ACK bit when the commander subscriber station (100) has correctly received a message (45), the responder subscriber station (101 ... 101N) does not send an ACK bit when the responder subscriber station (101 ... 101N) has correctly received a message (45), the Commander Participant Station (100) and the Responder Participant Station (101 ... 101N) do not perform any error signaling, The Commander Participant Station (100) and the Responder Participant Station (101 ... 101N) do not use overload frames, the Commander subscriber station (100) and the Responder subscriber station (101 ... 101N) do not perform automatic retransmission, and the Commander Participant Station (100) and the Responder Participant Station (101 ... 101N) does not perform an automatic shutdown of the Responder Participant Station (101 ... 101N) upon detection of a predetermined number of communication errors.

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