Commander subscriber station for a serial bus system, and method for communication in a serial bus system

Abstract

A commander subscriber station for a serial bus system and a method for communication in a serial bus system are provided. The commander subscriber station has a frame validity check block for checking whether a frame corresponding to a received signal is equal to a predetermined frame and is thus error-free and therefore valid. The frame validity check block is designed to carry out a first check as to whether the frame corresponding to the received signal is valid, if the bit time of the first communication phase of the predetermined frame has a predetermined value corresponding to a bit rate which is equal or less than a predetermined bit rate, and the frame validity check block is configured to carry out a second check as to whether the frame corresponding to the received signal is valid, if the bit time of the first communication phase of the predetermined frame has a predetermined value corresponding to a bit rate which is greater than the predetermined bit rate, the first check and the second check being at least partially different.

Description

[0001] R. 416159

[0002] - 1 -

[0003] Description

[0004] Commander subscriber station for a serial bus system and method for communication in a serial bus system

[0005] Technical field

[0006] The present invention relates to a commander subscriber station for a serial bus system and a method for communication in a serial bus system.

[0007] State of the art

[0008] Communication between devices in vehicles and / or other technical equipment often takes place via a bus system. The participating devices in such a bus system are also called nodes. These participating devices are technical equipment such as sensors, control units, etc.

[0009] Well-known bus systems include Classical CAN and / or CAN FD, both of which are standardized in the international standard ISO11898-1 :2024.

[0010] Furthermore, the CAN protocol variant CAN FD light, abbreviated as FDL, is now specified in Annex A to the ISO11898-1 :2024 standard for responders.

[0011] FDL is designed for CAN bus systems in which a Commander CAN subscriber station (Commander) controls the function(s) of several Responder CAN subscriber stations (Responders). To enable a more cost-effective connection of the Responders to CAN bus systems, the CAN variant CAN FD light according to ISO 11898-1:2024, Annex A, is implemented in the Responders. This uses CAN FD frames without bit rate switching. FDL R. 416159

[0012] - 2 - does not support arbitration. Therefore, the commander uses the "request send" principle, also known as "polling," to communicate with the responders.

[0013] The Commander is a control unit with a microcontroller that runs the application software and controls a responder. The microcontroller contains a CAN controller capable of sending and receiving CAN FD frames according to ISO 11898-1:2024. Sending and receiving a frame is also initiated by sending a CAN FD frame.

[0014] Responders are application-specific integrated circuits, also known as ASICs. Responders have little or no local processing power and can perform simple functions of a technical system, such as switching a light-emitting diode (LED) on / off or controlling the color of an LED. A responder only sends a CAN FD frame when requested to do so by the commander. Thus, after receiving a send request from the commander, each responder transmits its function information, such as a sensor value, to the commander via a CAN FD message.

[0015] To enable cost-effective integration of a responder onto a single ASIC in a mixed-semiconductor process, such as bipolar transistor(s), CMOS transistor(s), and DMOS transistor(s) (BCD technology), an FDL controller is integrated into the responder. The FDL controller is significantly simpler compared to a CAN FD controller.

[0016] This means that the FDL specification omits some features of the CAN FD protocol as specified in ISO 11898-1:2024. For example, fault confinement, for which an error counter is provided and error frames are created and sent as needed, has been eliminated. Furthermore, the responders are not configured to participate in CAN arbitration. The commander manages communication to avoid access conflicts on the CAN bus. Additionally, FDL communication uses only frames in FBFF format, which include an 11-bit identifier and no bit rate switching. This saves further ASCII space and simplifies clocking. R. 416159

[0017] - 3 -

[0018] Recovery from the CAN bit stream to save a quartz oscillator in the responder.

[0019] For bit rates up to 2 Mbit / s, a CAN controller compliant with ISO 11898-1:2024 can be used as a commander. Therefore, any currently available CAN FD subscriber station can be used as a CAN FD light commander.

[0020] To enable bit rates up to 8 Mbit / s, ISO 11898-1:2024 describes modifications to the behavior of the responder in Annex A. For bit rates up to 8 Mbit / s, further modifications to the behavior of the commander are described in the currently unfinished document CiA604-3. This document introduces a configuration option called "CAN FD light Commander operation mode for high bit rates," abbreviated as LCHB mode. If LCHB mode is not activated, the CAN subscriber behaves according to the current description in ISO 11898-1:2024. However, if LCHB mode is activated, the specified modifications are enabled, and FDL communication at higher bit rates becomes possible.These specified modifications include disabling bus monitoring, disabling the requirement for the commander to send an ACK response to a responder message, disabling the sending of error frames and overload frames, and disabling fault confinement. To minimize the implementation and verification effort for LCHB mode, the number of modifications should be kept to a minimum.

[0021] However, the problem is that the functions currently specified in CiA604-3 are not sufficient to convert a CAN controller according to ISO 11898-1:2024 into a CAN FDL Commander for bit rates higher than 2 Mbil / s, for example up to 8 Mbil / s.

[0022] Disclosure of the invention R. 416159

[0023] - 4 -

[0024] Therefore, the object of the present invention is to provide a commander subscriber station for a serial bus system and a method for communication in a serial bus system that solve the aforementioned problems. In particular, a commander subscriber station for 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 with a responder subscriber station is possible with high error robustness, a higher bit rate than previously possible, and a high net data transfer rate.

[0025] This problem is solved by a commander participant station for a serial bus system with the features of claim 1. The commander participant station has a communication control unit for controlling communication between the participant station and a responder participant 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, in which the bit time in a first communication phase may differ from a bit time in a second communication phase, a frame validity check block for checking whether a frame corresponding to the received signal is equal to a predetermined frame and thus error-free and therefore valid or not, wherein the frame validity check block is configured to perform a first check to determine whether the frame corresponding to the received signal is valid or not.If the bit time of the first communication phase of the predetermined frame has a predetermined value corresponding to a bit rate equal to or less than a predetermined bit rate, wherein the frame validity check block is configured to perform a second check to determine whether the frame corresponding to the received signal is valid or not, if the bit time of the first communication phase of the predetermined frame has a predetermined value corresponding to a bit rate greater than the predetermined bit rate, and wherein the first check and the second check are at least partially different. R. 416159

[0026] - 5 -

[0027] The described commander substation is suitable for FDL communication with a responder substation at bit rates of up to 8 Mbit / s. Specifically, bit rates greater than 2 Mbit / s, and particularly up to 8 Mbit / s, are supported. For bit rates up to 2 Mbit / s, an existing CAN controller and CAN transceiver in vehicles and / or other technical equipment specified for CAN FD according to the international standard ISO 11898-1:2024 can be used. In particular, a CAN SIC transceiver, which supports bit rates up to 8 Mbit / s, can be used.

[0028] The design of the Commander substation ensures that, even during FDL communication on the bus, the Commander substation can reliably verify the validity of received CAN frames. Furthermore, the Commander substation can reliably verify the validity of transmitted CAN frames. This enables very robust FDL communication with a Responder substation, even at bit rates of up to 8 Mbit / s. This is also due to the minimization of the risk of unnecessary communication interruptions on the bus caused by incorrect validity checks.

[0029] A significant advantage is that the described commander participant station can be created very easily by modifying an existing CAN VHDL description and then using it, for example, in a field-programmable (FPGA) logic gate array. New integrated circuits for CAN (CAN ICs) can also be created from the VHDL description. This makes it very easy and therefore cost-effective to configure an existing CAN bus system for FDL communication. "VHDL" stands for "VHSIC Hardware Description Language" or "Very High Speed ​​Integrated Circuit Hardware Description Language".

[0030] Therefore, the described Commander substation supports more than one frame format. Thus, the Commander substation can be configured to select from at least two different frame formats a frame format in which the next frame is to be sent to the bus. The described Commander substation can therefore be specifically configured to... R. 416159

[0031] - 6 - as required, turn at least one predetermined function, for example its synchronization function, off or on for a predetermined frame or a frame in a predetermined frame format.

[0032] This makes the Commander subscriber station very advantageous to use in applications where data needs to be exchanged between the Commander subscriber station and at least one responder subscriber station connected via the bus in a shorter time than before.

[0033] Overall, the described participant station contributes to making the bus system more cost-effective, while still enabling robust and reliable CAN communication.

[0034] Further advantageous configurations of the participant station are specified in the dependent requirements.

[0035] The previously described commander participant station can also include a first frame validity check unit for checking the at least one signal received from the bus, for which the commander participant station is only a receiver but not the sender, up to a first position in the predetermined frame, to determine whether a valid frame has been received or not, and a second frame validity check unit for checking the at least one signal received from the bus, for which the commander participant station is the sender, up to a second position in the predetermined frame, or for checking a signal generated from the predetermined frame and to be sent to the bus, to determine whether a valid frame has been sent or not, wherein the frame validity check block performs a check when the first and second frame validity check units are not active.and wherein the first and second frame validity check units are activated to perform their checks when the bit time of the first communication phase of the predetermined frame has a predetermined value corresponding to the bit rate which is greater than the predetermined bit rate. R. 416159

[0036] - 7 -

[0037] The second position may be arranged later in the predetermined frame than the first position.

[0038] The Commander subscriber station described above can be a CAN FD subscriber station, where the predetermined frame is a CAN FD frame in the FBFF format.

[0039] According to one embodiment, the first position is one of the following positions, namely the start of the ACK slot bit, the last bit of a checksum, the penultimate bit of a frame end field.

[0040] According to another embodiment, the second position is the sampling time of the last bit of a frame end field.

[0041] According to yet another embodiment, the second frame validity test unit is designed to perform its test until the last bit of a checksum of the signal to be sent to the bus has been sent.

[0042] According to yet another embodiment, the second frame validity test unit is designed to perform its test up to the beginning of the ACK slot bit of the signal to be sent to the bus.

[0043] According to yet another embodiment, the second frame validity test unit is designed to perform its test up to the ACK bit slot of the signal to be sent to the bus.

[0044] It is conceivable that the previously described commander participant station also has a configuration block in which a value for at least one LCHB mode configuration bit is stored, indicating whether the bit rate is greater than the predetermined bit rate.

[0045] It is possible that the previously described commander subscriber station also has an LCHB mode module for activating the first and second frame validity check units if the bit time of the first communication phase R. 416159

[0046] - 8 - of the predetermined frame has a predetermined value corresponding to the bit rate which is greater than the predetermined bit rate, and to disable the first and second frame validity check unit if the bit time of the first communication phase of the predetermined frame has a predetermined value corresponding to the bit rate which is equal to or less than the predetermined bit rate.

[0047] The LC HB mode module may also include an evaluation block for evaluating the value of at least one LCHB mode configuration bit, and a switching block for activating or deactivating the first and second frame validity check units based on the evaluation of the evaluation block.

[0048] The predetermined bit rate is possibly 2 Mbil / s.

[0049] The commander participant station described above may not be part of a bus system which also has a bus and at least two participant stations which are connected to each other via the bus in such a way that they can communicate serially with each other, and of which one participant station is the commander participant station and at least one participant station is a responder participant station, wherein the responder participant station has a communication control device for controlling communication between the responder participant station and the commander participant station and for evaluating at least one signal received from the bus based on the predetermined frame, and wherein each of the at least two participant stations also has a transmit / receive device for sending a transmit signal to the bus and / or for receiving a signal from the bus.

[0050] The aforementioned problem is further solved by a method for communication in a serial bus system according to claim 15. The method is carried out with a previously described commander subscriber station and a responder subscriber station, wherein the responder subscriber station has a communication control device for controlling communication between the responder subscriber station and the commander subscriber station of R. 416159.

[0051] - 9 -

[0052] bus system and for evaluating at least one signal received from a bus of the bus system based on the predetermined framework.

[0053] The procedure offers the same advantages as previously mentioned in relation to the Commander Participant Station.

[0054] 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.

[0055] Drawings

[0056] The invention is described in more detail below with reference to the accompanying drawing and by means of exemplary embodiments. The drawing shows:

[0057] Fig. 1 shows a simplified block diagram of a bus system according to a first embodiment;

[0058] Fig. 2 shows the format of CAN FD frames in FDL format, in particular FBFF format without bit rate switching, for a message that can be sent by a transmit / receive device for a subscriber station of the bus system according to the first embodiment;

[0059] Fig. 3 shows a simplified schematic block diagram of a first subscriber station (Commander) of the bus system according to the first embodiment;

[0060] Fig. 4 shows 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 as at least one second subscriber station;

[0061] Fig. 5 shows a time course of bus signals CAN_H and CAN_L at the first subscriber station according to the first embodiment; R. 416159

[0062] - 10 -

[0063] Fig. 6 shows a time course of a differential voltage VDIFF of the bus signals CAN_H and CAN_L at the first subscriber station according to the first embodiment;

[0064] Fig. 7 shows 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 of the first subscriber station; and

[0065] Fig. 8 shows a simplified schematic block diagram of a second subscriber station (responder) of the bus system according to the first embodiment.

[0066] In the figures, identical or functionally equivalent elements are provided with the same reference symbols unless otherwise specified.

[0067] Description of the exemplary implementations

[0068] Fig. 1 shows, as an example, a bus system 1, which is fundamentally designed for a CAN bus system, a CAN FD bus system, and / or variations thereof, as described below. The bus system 1 can be used in a vehicle, in particular a motor vehicle, an aircraft, etc., or in a hospital, etc.

[0069] In Fig. 1, the bus system 1 has a bus 40 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. One to N responder stations 101, 102, 103 ... 10N can be connected to the bus 40. The bus 40 can have a first bus wire 41 (Fig. 3) and a second bus wire 42 (Fig. 3), which are not shown in Fig. 1. The bus wires can also be called CAN_H and CAN_L and serve for electrical signal transmission after coupling in the dominant levels or generating recessive levels or other levels for a signal in the transmit state. R. 416159

[0070] - 11 -

[0071] The Commander subscriber station 100 is, for example, a control unit of a motor vehicle or other technical system, as described in more detail below. The Responder subscriber stations 101, 102, 103 ... 10N can, for example, include at least one sensor, at least one display device, at least one actuator, at least one transmitter, etc., of a motor vehicle or other technical system, as described in more detail below.

[0072] As shown in Fig. 1, the Commander subscriber station 100 has a communication control unit 11, a transmit / receive unit 12 and an LCHB mode module 15. LCHB stands for Light Commander High Bitrate, which will be described in more detail later.

[0073] Each of the responder stations 101, 102, 103 ... 10N has a communication control unit 21, a transmit / receive unit 22, and an LRHB mode module 25. LRHB stands for Light Responder High Bitrate, which will be described in more detail later. The transmit / receive units 12, 22 of the responder stations 101 ... 10N are each directly connected to the bus 40, although this is not illustrated in Fig. 1.

[0074] The Commander substation 100 is configured to generate messages 45 in the form of signals. Furthermore, the Commander substation 100 is configured to send messages 45 in the form of signals to one of the substations 101 ... 10N via bus 40. The LCHB mode module 15 comprises blocks and / or circuit components that can be used to implement an LCHB mode, which enables the substation 100 to operate with FDL at bit rates higher than 2 Mbit / s and up to 8 Mbit / s. The LCHB mode is also called "CAN FD light Commander operation mode for high bit rates" or CAN FD light Commander operating mode for high bit rates.

[0075] The participant stations 101 ... 10N in Fig. 1 are configured to generate messages 45 in the form of signals and send them via bus 40 to the commander participant station 100. Messages 45 can be transmitted serially between participant station 100 and any of the participant stations 101 to 10N. The LRHB mode modules 25 are used to execute the LRHB mode, which is described in R. 416159.

[0076] - 12 -

[0077] Operation of the respective subscriber station 101 ...10N with FDL at bit rates higher than 2 Mbil / s and up to 8 Mbil / s is enabled

[0078] The communication control units 11 and 21 each serve to control communication between the subscriber station 100 and one of the subscriber stations 101 to 10N via bus 40. The communication control units 11 and 21 generate a transmit signal TxD as needed, which is described in more detail below with reference to Fig. 4. In addition, the communication control units 11 and 21 read and decode a receive signal RxD, which is described in more detail below with reference to Fig. 7.

[0079] The communication control unit 11 can be implemented, at least partially, like a conventional CAN controller according to ISO 11898-1:2024, i.e., like a CAN FD controller or a CAN FD-tolerant Classical CAN controller. The CAN FD messages 45 can comprise a number of 0 to 64 data bytes, which, unlike FDL communication, are also transmitted at a significantly faster data rate than a Classical CAN message.

[0080] The communication control unit 11 is also designed to provide a message 45 to one of the subscriber stations 101 ... 101 N or to receive a message 45 from one of the subscriber stations 101 ... 101 N, as required. For sending and receiving the message 45, the LCHB mode module 15 or the LRHB mode module 25 is used, as described in more detail below. The message 45 is based on a CAN FD format, which is usable for CAN FD or FDL, as described in more detail with reference to Fig. 2.

[0081] The communication control unit 11 is thus configured to create or read a message 45 intended for communication on bus 40 according to CAN FD (first data transmission standard) or for communication on bus 40 according to FDL (second data transmission standard). For CAN FD, the communication control unit 11 performs a frame validity check as described in R. 416159.

[0082] - 13 - specified in the standard IS011898-1 :2024 In the LCHB mode of FDL, the communication control unit 11 performs a frame validity check modified with the LCHB mode module 15, as described in more detail below.

[0083] As previously mentioned regarding the state of the art, FDL communication uses only frames without bit rate switching. Furthermore, FDL communication, including LCHB mode, does not perform arbitration, where, during the arbitration phase of message 45, it is negotiated which participating station has exclusive access to bus 40 in the following data phase.

[0084] The communication control unit 21 is implemented as an FDL controller, which, during FDL communication, is configured for frame validity checks as specified in Annex A to the ISO 11898-1:2024 standard. Furthermore, the LRHB mode module 25 is present, which has functions compatible with those of the LCHB mode module 15. The communication control unit 21 also generates messages 45 for FDL communication on bus 40 and is configured to read messages 45 during FDL communication.

[0085] To communicate with one of the subscriber stations 101 ... 100 N, subscriber station 100 sends a send request to the desired subscriber station 101 ... 100 N via bus 40. The send request is made by sending a message 45 with a frame 450 for FDL communication, which is shown in Fig. 2. A responder subscriber station 101 ... 100 N only sends a message 45 for FDL communication via bus 40 to the commander subscriber station 100 if subscriber station 100 has requested subscriber station 101 ... 100 N to do so by sending a send request.

[0086] Thus, station 100 functions as a commander / queryer, and station 101 ... 101 N functions as a responder. Therefore, station 100 is subsequently referred to as the FDL Commander, and station 101 ... 101 N as the FDL Responder. R. 416159

[0087] - 14 -

[0088] Fig. 2 shows a frame 450, created by the subscriber station 100, for a message 45 with up to 64 data bytes in CAN FD FBFF format. The CAN FD frame 450 can be provided by the communication control unit 11, namely encoded in a digital transmit signal TxD, to the associated transmit / receive unit 12 for transmission on bus 40. The CAN FD frame 450 can be sent in an FDL communication to one of the subscriber stations (responders) 101 ... 10N. However, it is also possible for the CAN FD frame 450 to be sent in a CAN FD communication to another CAN FD subscriber station (not shown). This other CAN FD subscriber station (not shown) can, in particular, be connected to the subscriber station 100 via a second bus (not shown).

[0089] If the substation 100 is a CAN FD substation according to the international standard ISO 11898-1:2024, the substation 100 is also configured to send frames in another CAN format, in particular the CAN FD FEFF format. These other CAN formats are known from ISO 11898-1:2024 and are therefore not described below.

[0090] The frame shown in Fig. 2 can also be provided by a responder station 101 ... 10N or its communication control unit 21, encoded in a digital transmit signal TxD, for transmission to the associated transmit / receive unit 22 on the bus 40. In this embodiment, the communication control unit 21 creates the frame 450 as compatible with CAN FD, as illustrated in Fig. 2. The frame 450, which is used for FDL communication between the responder station 100 and one of the responders 101 ... 10N, can also be referred to as an FDL frame. Such FDL frames can be sent and received by any CAN FD responder station at a bit rate of up to 2 Mbit / s.

[0091] As shown in Fig. 2, frame 450 is divided into two communication phases, called arbitration phase 451 (first communication phase) and data phase 452 (second communication phase). Frame R. 416159

[0092] - 15 -

[0093] Frame 450 begins and ends in the arbitration phase 451. Frame 450 begins with a SOF bit and has an arbitration field 453, a control field 454, a data field 455, a checksum field 456, an acknowledgment field 457, and an end of frame field EOF.

[0094] Bits in the arbitration phase 451 of frame 450 may have a longer bit time than bits in the data phase 452, as illustrated in Fig. 2. The switch from the bits with the bit time of the arbitration phase 451 to the bits with the bit time of the data phase 452 occurs in a BRS bit, as labeled SP in Fig. 2.

[0095] Bits represented by a thick line at their lower edge in Fig. 2 are transmitted as dominant or '0' in frame 450. Bits represented by a thick line at their upper edge in Fig. 2 are transmitted as recessive or '1' in frame 450. Such bits, represented by a thick line in Fig. 2, have a predetermined fixed or set value in frame 450.

[0096] The arbitration field 453 includes an identifier from frame 450 in the ID field. The identifier has bits ID 28 to ID 18, totaling 11 bits. An RRS bit is located at the end of the arbitration field 453. Fig. 2 thus shows the FBFF format with the 11-bit identifier.

[0097] Control field 454 begins with an IDE bit, followed by an FDF bit, which in turn is followed by a res bit. These are followed by a BRS bit and an ESI bit. The ESI bit is therefore the first bit in frame 450, with the bit time corresponding to data phase 452.

[0098] The sender of frame 450 in Fig. 2 can decide whether to set the BRS bit to 1 or 0, where BRS stands for Bit Rate Switch. If the BRS bit is set to 1, the bit rate is increased or the bit time is reduced in data phase 452. If the BRS bit is set to 0, the bit rate or bit time is the same in both communication phases 451 and 452. In FDL, it is currently provided that the bit rate within frame 450 is not R. 416159

[0099] - 16 - is switched. Therefore, BRS=O is sent. In this case, the Commander (participant station 100) must set the BRS bit to 0 in a message 45 to the Responder (one of the participating stations 101 ... 10N) so that the Responder understands the Commander.

[0100] Control field 454 ends with a DLC field encoded with the length of the following data field 455. The res bit must be sent with a logical value of 0, in other words (logical) 0, i.e., dominant, for frame 450.

[0101] Data field 455 is not present if the DLC field of control field 453 has the value 0. Data field 455 has a length corresponding to the value encoded in the DLC field. The value can be up to 64 bytes, as mentioned previously.

[0102] The checksum field 456 contains, in a field SBC, the number of stuff bits modulo 8 that were inserted into frame 450 according to the bit stuffing rule, namely, after every five identical bits, an inverse bit is inserted. Additionally, the checksum field 456 contains a CRC checksum in a CRC field, which can also be called a CRC checksum, and ends with a subsequent CRC del bit, also called a CRC delimiter.

[0103] The switch from the bits with the bit time of the data phase 452 to the bits with the bit time of the arbitration phase 451 takes place in the CRC-Del bit, as labelled SP in Fig. 2.

[0104] Acknowledge field 457 contains an ACK bit slot in which participating stations, which are currently only receivers of frame 450 but not transmitters of the frame, can confirm or deny the correct reception of frame 450 from bus 40 during CAN FD communication. Acknowledge field 457 ends with an ACK-Del bit, also called the ACK delimiter.

[0105] The frame end field EOF contains a bit sequence that marks the end of frame 450. Thus, the bit sequence of the frame end field R. 416159

[0106] - 17 -

[0107] The End of Frame (EOF) is used to mark the end of frame 450. Together with the ACK Del bit, the EOF ensures that a set of eight recessive bits is sent at the end of frame 450. This is a bit sequence that cannot occur within frame 450. This allows the end of frame 450 to be reliably detected by the subscriber stations 100, 101 ... 10N.

[0108] Following the end-of-frame field (EOF), which has 7 bits, frame 450 contains an interframe space (IFS), which is not shown in Fig. 2. This interframe space (IFS) is configured in CAN FD according to ISO 11898-1:2024. The interframe space (IFS) has a minimum of 3 bits.

[0109] Furthermore, the fields and bits mentioned are known from ISO11898-1 :2024 and are therefore not described in detail here.

[0110] If frame 450 from Fig. 2 is used for CAN FD communication, in the arbitration phase 451 of CAN FD, the identifier (ID) with, for example, bits ID28 to ID18 in the arbitration field 453 is used to negotiate bitwise between participating stations 100 or other CAN FD participating stations on bus 40 which participating station 100 wants to send the message 45 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 is used, as in CAN and CAN-FD. The physical layer corresponds to the physical layer or layer 1 of the well-known OSI model (Open Systems Interconnection model).The sender station 100 of a message 45 only begins transmitting bits of the data phase 452 to bus 40 once the sender station 100 has won the arbitration and thus has exclusive access to bus 40 of bus system 1 for transmission. The same applies to every CAN FD sender station connected to bus 40 that wants to send a message 45 to bus 40. R. 416159.

[0111] - 18 -

[0112] The subscriber stations 101 ... 10N, acting as FDL responder stations, do not support arbitration, as previously mentioned and described in more detail below. To avoid using CAN arbitration, where the familiar CSMA / CR method resolves a collision when two CAN nodes (subscriber stations) simultaneously initiate a message, the commander must specify when each responder is permitted to send a message. This means that if the commander has requested a specific responder to send a message, the commander waits until the responder has responded before sending any other message. If a responder that has received a send request but has not yet initiated its response sees the beginning of another message on CAN bus 40, it considers its send request complete and does not initiate its message 45.Annex A of ISO 11898-1:2024 specifies the earliest possible time at which a responder may answer a send request with a message. This send start can be delayed if the responder needs more time to prepare the send data. The response times of the various responders in the CAN system are known to the commander.

[0113] Collisions between FDL responders (subscriber stations 101...10N) and the commander (subscriber station 100) or any other CAN FD nodes (e.g., subscriber stations 100) that contain the arbitration function can also be avoided by assigning identifiers with a higher arbitration priority to the responders for sending messages. This causes the other nodes, if they initiate a message simultaneously with a responder, to lose arbitration and become receivers.

[0114] In FDL communication, the communication control unit 11 is configured as an FDL commander and writes the identifier (ID) assigned to the commander and one of the responders into frame 450. The communication control unit 21 is configured as an FDL responder and writes the identifier (ID) assigned to the responder into frame 450. For example, if the subscriber station 101 (responder) receives a send request from the subscriber station 100 (commander), the subscriber station 101 sends an FDL frame 450 as shown in Fig. 2, or a message 45, via bus 40 to the subscriber station 100. R. 416159

[0115] - 19 -

[0116] In CAN communication and FDL, the identifiers (IDs) are sender addresses or content information, but not receiver addresses. Each identifier may only be sent by a predetermined participating station (100 to 10N) so that the commander can recognize the respective sender. If a participating station (100 to 10N) can send different data packets, this participating station, and only this station, may use different identifiers (IDs) to send these data. However, for simplicity, the commander could poll the responders using different identifiers (IDs). Alternatively, the commander could poll the responders using a frame (450) with a general query identifier (ID) and then encode in data field (455) of this frame (450) which responder is meant. The intended responder then replies, each using its own identifier (ID).

[0117] When switching to data phase 452, no bit rate switching occurs within frame 450. This means that the bit time of bits in the arbitration phase 451 and the data phase 452 is the same. However, it is possible that the bit time in the first communication phase (arbitration phase) 451 may differ from the bit time in the second communication phase (data phase) 452.

[0118] As with CAN FD, FDL uses 452 recessive and dominant levels for data transmission on the bus.

[0119] Fig. 3 shows the basic structure of the subscriber station 100 with the communication control unit 11 and the transmit / receive unit 12 as well as with the LCHB mode module 15, which is part of the communication control unit 11.

[0120] According to Fig. 3, the subscriber station 100 has, in addition to the communication control unit 11 and the transmit / receive unit 12, a microcontroller 13 to which the communication control unit 11 is assigned, and a system ASIC 16 (ASIC = Application-Specific Integrated Circuit), which can alternatively be a system base chip (SBC), on R. 416159

[0121] - 20 - which combines several functions necessary for an electronic assembly of the participant station 100. 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, using data from a rain sensor and / or wind sensor and / or speed sensor and / or light sensor, controls the movement of at least one windshield wiper (actuator) and / or a warning light (actuator) can be switched on or off. However, the application is not limited to a windshield washer system or parts thereof.

[0122] Alternatively, the participant station 100, in particular its system ASIC 16, is designed for networking in functional areas. Such an area is also called a "domain." Examples of such areas are engine management, chassis control, lighting, comfort system, etc. The areas are then connected via gateways. A microcontroller 13 of the lighting domain can then be used as an FDL commander for controlling light-emitting diodes (LEDs).

[0123] Alternatively, the subscriber station 100 can be used in a zone architecture, which simplifies the wiring harness that accounts for an ever-increasing proportion of the vehicle's weight and cost. In a zone architecture, for example, a vehicle is spatially divided into zones. The devices located in a zone are interconnected by short cables. The zones are connected via gateways to backbones that communicate at very high bit rates, up to Gigabit Ethernet.

[0124] In addition to the transmitter / receiver unit 12, the system ASIC 16 incorporates a power supply unit 17, which provides electrical power to the transmitter / receiver unit 12. The power supply unit 17 typically provides a CAN_Supply voltage of 5 V. Depending on requirements, the power supply unit R. 416159

[0125] - 21 -

[0126] However, 17 can supply a different voltage with a different value. Additionally or alternatively, the power supply device 17 can be configured as a current source.

[0127] If the communication control unit 11 acts as an FDL commander, the communication control unit 11 may create a frame 450 in which no bit rate switching / bit rate change takes place, as described above, and / or evaluate such a frame 450.

[0128] The LC HB mode module 15 has at least one function block 151, in particular two, as shown in Fig. 3, or more, a configuration block 152, an evaluation block 153, a switching block 154, and a frame validity check block 155. In particular, a value for at least one LCHB mode configuration bit 1521 can be stored in the configuration block 152. The frame validity check block 155 is designed for frame validity checks and has a first frame validity check unit 1551 and a second frame validity check unit 1552 for the LCHB mode. The frame validity check units 1551 and 1552 can thus be activated for the LCHB mode, but are otherwise not required and can therefore be deactivated. However, the frame validity test units 1551 , 1552 do not have to be part of the frame validity test block 155, but can be arranged separately from the frame validity test block 155 in the LCHB mode module 15 and / or the communication control unit 11.

[0129] Frame validity check block 155, regardless of whether LCHB mode is enabled or disabled, performs a validity check on frames 450 received from bus 40 to ensure that only error-free data packets are forwarded to higher protocol layers of the OSI (Open Systems Interconnection) layer model.

[0130] Furthermore, the frame validity check block 155, regardless of whether LCHB mode is enabled or disabled, performs a validity check for frames 450 sent on bus 40 in order to confirm to higher protocol layers of the OSI model that frame 450 was successfully transmitted. R. 416159

[0131] - 22 - could be sent. For unsuccessfully transmitted frames 450, the subscriber station 100 has a retransmission function.

[0132] If the LCHB mode is activated with the LC HB mode module 15, the first and second framework validity test units 1551 and 1552 are activated. Thus, the first and second framework validity test units 1551 and 1552 are used in the LCHB mode. If the LCHB mode is not activated, the framework validity test block 155 performs a framework validity test as described below. Furthermore, the test units 1551 and 1552 for the LCHB mode are described in more detail below.

[0133] The at least one function block 151 can be deactivated for LCHB mode using the LCHB mode module 15. The at least one function block 151 can, in particular, comprise one of the following function blocks: a synchronization block, a bus monitoring block, an error and overload frame transmission block, and an error limitation block. The functions of the aforementioned function blocks 151 are described in more detail below. The synchronization block can comprise or be the bit-timing control unit (BTL) of the communication control device 11.

[0134] The LCHB mode module 15, in particular the evaluation block 153 and the switching block 154, can be implemented at least partially as software.

[0135] The transceiver 12, in addition to the system ASIC 16, also has a transmit module 121 and a receive module 122. Although the following text always refers to the transceiver 12, it is alternatively possible to provide the receive module 122 in a separate unit external to the transmit module 121. The transmit module 121 and the receive module 122 can be constructed like a conventional transceiver 22. In particular, the transmit module 121 can include at least one operational amplifier and / or one transistor. The receive module 122 can also include at least one operational amplifier and / or one transistor. R. 416159

[0136] - 23 -

[0137] 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 supplied 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.

[0138] The first and second bus wires 41, 42 are connected in the transmit / receive device 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, although the connection is not shown in Fig. 3 for the sake of simplicity.

[0139] During operation of bus system 1, the transmitter module 121 of Fig. 3 can serially convert a transmission signal TxD from the communication control unit 11 into corresponding signals CAN_H, CAN_L for CAN or CAN FD for the bus wires 41, 42, and send these signals to bus 40 at the CAN_H and CAN_L terminals. The communication control unit 11 transmits the transmission signal TxD from Fig. 4 serially via terminals TXD to the transmitter module 121 over a time interval t, as shown in Fig. 3. As shown in Fig. 4, the transmission signal TxD has voltage states H (High) and L (Low) with a corresponding voltage U.

[0140] As shown in Fig. 5, the signals CAN_H and CAN_L have the dominant and recessive bus levels 401 and 402, respectively, during arbitration phase 451, as is known from CAN. A differential signal VDIFF = CAN_H - CAN_L is generated on bus 40, as shown in Fig. 6 for arbitration phase 451. The individual bits of the VDIFF signal, with bit time t_bt1, can be detected in both arbitration phase 451 and data phase 452 with a receive threshold T_a of, for example, 0.7 V. During data phase 452 of a frame 450, the bits of the signals CAN_H and CAN_L can be transmitted faster, i.e., with a shorter bit time t_bt2, than during arbitration phase 451, as mentioned previously. Thus, the signals CAN_H and R differ. 416159

[0141] - 24 -

[0142] CAN_L in CAN FD for frame 450 in data phase 452, at least at its faster bit rate, is transmitted faster than the conventional signals CAN_H and CAN_L. In FDL frames, all bits are transmitted with the same bit time, t_bt1 = t_bt2.

[0143] The sequence of states H, L of the transmit signal TxD from Fig. 4 and the resulting states 401, 402 for the signals CAN_H, CAN_L in Fig. 5, as well as the resulting voltage waveform VDIFF from Fig. 6, serve only to illustrate the function of the receiving station 100. The sequence of data states for the bus states 401, 402 can be selected as needed.

[0144] The receiver module 122 generates a receive signal RxD from the CAN_H and CAN_L signals received from bus 40, shown in Fig. 5, or from the differential voltage VDIFF of Fig. 6. The receiver module 122 uses reception thresholds (not shown) to generate the digital receive signal RxD of Fig. 7. The receive signal RxD is shown in Fig. 7 without propagation delay. The receiver module 122 forwards this receive signal RxD to the associated communication control unit 11, as shown in Fig. 3.

[0145] In the operation of bus system 1, the subscriber station 100 (commander), more precisely the communication control unit 11, in particular a bus monitoring block as a function block 151 of at least one function block 151, performs bus monitoring. According to ISO 11898-1:2024, the subscriber station 100, in particular the communication control unit 11, compares its own transmitted bits at a sample point AP (shown in Fig. 5 and Fig. 6), according to a frame 450 and a transmit signal TxD (Fig. 4), with the bits observed on bus 40 according to the receive signal RxD (Fig. 7). A difference is considered an error, except for the arbitration and the ACK bit.

[0146] However, the subscriber station 100 (Commander), more precisely the LCHB mode module 15 of the communication control unit 11, deactivates bus monitoring. The LCHB mode is to be executed for short bit times t_bt1, t_bt2. In particular, the bit times t_bt1, t_bt2 are equal, as described previously. Such shorter bit times occur at bit rates above 2 Mbil / s, as per R. 416159.

[0147] - 25 - where the so-called loop delay of the subscriber station 100 (CAN node) reaches the range of a bit time t_bt1 , t_bt2 or more. The so-called loop delay indicates the time that elapses until the subscriber station 100 can internally see the bit of the transmit signal TxD sent via the TXD port as a bit of the receive signal RxD sent via the RXD port.

[0148] Furthermore, the participant station 100 (Commander), more precisely the communication control unit 11, performs a synchronization function for all frames 450 during the operation of the bus system 1, which have bits with a bit time t_bt1, t_bt2 for bit rates up to 2 Mbil / s. The synchronization function can, in particular, be executed by a synchronization block, which is a function block 151 of at least one function block 151.

[0149] The synchronization block (function block 151) monitors the edges from recessive to dominant or vice versa, i.e., a change between states 401, 402 or 402, 401 in Fig. 5 or Fig. 6. Based on the monitored edges, synchronization block 151 synchronizes the position of the sample point AP within a bit time t_bt1, t_bt2. A receiver thus 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. If an edge occurs between the beginning of a bit time t_bt1, t_bt2 and the sample point, it is called a late edge. This triggers synchronization, in which the current bit time t_bt1, t_bt2 is extended. If an edge occurs between the sample point AP and the end of a bit time t_bt1 , t_bt2, it is called an early edge.This causes a synchronization in which the current bit time t_bt1 , t_bt2 is shortened.

[0150] According to ISO 11898-1:2024 and the FDL specification according to CiA 604-3, which refers to ISO, the senders of a frame 450 also synchronize. However, there is a limitation: a receiving station 100 transmitting a dominant bit does not synchronize to late edges. This is because, due to the loop delay, the sender sees all its own transmitted bits as late. Therefore, synchronization based on these would be impossible. R. 416159

[0151] - 26 - Late edges lengthen these bits and distort the bit rate. Allowed synchronization on early edges stabilizes CAN arbitration at the beginning of frame 450. Synchronization on the ACK edge, at which the sender transmits a recessive bit, synchronizes all participating stations in bus system 1 to the same edge.

[0152] The synchronization function is described in more detail in ISO 11898-1 :2024 and the FDL specification according to the CiA document CiA604-3 for Commander and Annex A for Responder.

[0153] Furthermore, the "Sending Error and Overload Frames" function of ISO 11898-1:2024 can be executed using an error and overload frame transmission block as function block 151. This function includes signaling detected errors using error flags and overload flags to enable fault confinement in the CAN network. This fault confinement is omitted in the subscriber stations 101 ... 10N (FDL responders), as described previously, to allow for smaller implementations. Therefore, FDL responders do not send error flags or overload flags. Moreover, the subscriber stations 101 ... 10N (FDL responders) do not respond to these flags. Therefore, error flags sent by subscriber station 100 (FDL commander) are also not relevant. and overload flags are unnecessary, as these flags only delay the start of data frames.Data frames are frame 450, which contain data in data field 455. Therefore, in LCHB mode, no error flags or overload flags are sent by the participating station 100 (FDL Commander).

[0154] Furthermore, the "Fault Confinement" function of ISO 11898-1:2024 can be executed using a fault confinement block as function block 151. This function includes fault confinement with separate error counters for a sender and a receiver. The counters are incremented in the event of an error and decremented for successful frame 450 transmissions. High error counter values ​​change the behavior of the CAN subscribers on bus 40, particularly the sending of error messages. (R. 416159)

[0155] - 27 -

[0156] Flags. In LCHB mode, no error flags are sent in the CAN FD light Commander; therefore, the "Fault Confinement" function is also switched off or deactivated.

[0157] With the LCHB mode module 15, the previously described function of at least one function block 151 can be switched on as needed, as described below. In particular, all previously described function blocks 151 can be switched on or off together.

[0158] Evaluation block 153 is configured to evaluate the LCHB mode configuration bit 1521 in configuration block 152. The LCHB mode configuration bit 1521 is set when the receiving station 100 (Commander), more precisely the communication control unit 11, is to send frame 450 with a bit time t_bt1 of the first communication phase 451 that corresponds to a bit rate greater than a predetermined bit rate. The predetermined bit rate is, in particular, greater than 2 Mbil / s.

[0159] If the evaluation of evaluation block 153 shows that the LCHB mode configuration bit 1521 is set, evaluation block 153 checks whether the subscriber station 100 (commander), more precisely the communication control unit 11, should (currently) act as a sender, i.e., send a frame 450 for FDL communication to a responder on bus 40. The LCHB mode configuration bit 1521 is set, for example, together with the bit rate configuration, either via software or hardwired. During operation of bus system 1, this bit is then constant. If the evaluation of evaluation block 153 shows 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 for FDL communication on bus 40, the evaluation block 151 instructs the switching block 154 to switch off at least one function block 151.Switching block 154 thus switches off at least one function block 151 and therefore its previously described function for all bits of the frame 450 to be sent by the participant station 100 as commander to bus 40 up to the last bit of the frame end field (EOF). R. 416159.

[0160] - 28 -

[0161] By disabling at least one function block 151, the synchronization function and / or at least one of the other previously mentioned functions of function blocks 151 are deactivated. Disabling the synchronization function prevents the transmitter from synchronizing to its own transmitted edges, which it does not perceive within the transmitted bit, but rather in one of the subsequent bit times. Consequently, synchronization cannot cause reception errors in the other participating stations 101 ... 10N of the bus system.

[0162] After the last bit of the frame end field (EOF) of the transmitted frame, the switching block 154 of Fig. 3 switches the at least one function block 151 and thus its previously described functions back on.

[0163] In the operation of bus system 1, the participant station 100 (Commander), more precisely the communication control unit 11, and in particular the frame validity check block 155, performs different frame validity checks in LCHB mode than those specified in ISO 11898-1:2024 and the FDL specification according to Annex A of ISO 11898-1:2024. Accordingly, with the LCHB mode module 15, the functions of the test units 1551 and 1552 of the frame validity check block 155 can be activated or deactivated as needed using the switching block 154, and thus switched, as previously described for the function blocks 151. In particular, all previously described function blocks 151 and the function of the frame validity check block 155 can be switched on or off together.

[0164] More precisely, the framework validity check block 155 performs the following checks to determine whether the current framework 450 is valid on bus 40 or not.

[0165] If LCHB mode is activated, and the subscriber station 100 (Commander) is currently receiving a frame 450 from bus 40, the frame validity check block 155 uses the first frame validity check unit 1551. The first frame validity check unit 1551 determines whether the frame 450, which R. 416159

[0166] - 29 - currently being transmitted to or received by bus 40, is valid or not.

[0167] The first frame validity check unit 1551 is designed such that the receiving station 100 (Commander) in LCHB mode accepts a frame 450 as valid if the receiving station 100 (Commander), in particular its check block 155, does not detect an error until the receiving station 100 (Commander) reaches the start of the ACK bit slot. Furthermore, the receiving station 100 (Commander), as the receiver, does not send an acknowledgment response (ACK) in the ACK bit slot. The absence of the acknowledgment response (ACK) in the ACK bit slot is not interpreted as an error by the sender of frame 450.

[0168] An advantage of this position for the validity check performed by the first frame validity test unit 1551 is that only a minor modification of the circuitry used by test block 155 for CAN FD frames 450 is required to confirm the validity of the frame 450 at this point in LCHB mode. This is because, when LCHB mode is deactivated, the receiving station 100 (Commander), acting as the receiver, checks the received CRC code at this point when it receives the bit preceding the ACK slot. In the frame 450 shown in Fig. 2 (FBFF format), the bit preceding the ACK slot is the CRC Del bit. At this point, the receiving station 100 (Commander) decides whether to send a dominant or a recessive ACK bit.

[0169] Another advantage of this position for the validity check performed by the first frame validity check unit 1551 is that a dominant level in one of the subsequent bits of the frame 450 received by bus 40 has no effect on the validity of the received frame 450. This improves data consistency between sender and receiver in the event of disturbances in the end-of-frame (EOF) field of frame 450.

[0170] If the subscriber station 100 (Commander), more precisely the communication control unit 11, is not switched to LCHB mode, i.e., the frame validity check unit 1551 is not activated, block 155 R. 416159

[0171] - 30 - The following check, according to the specification in ISO 11898-1:2024, is performed to determine whether the current frame 450 on bus 40 is valid or not. If the subscriber station 100 (Commander) is the receiver for the current frame 450 on bus 40, it must send a response with the ACK bit as receiver. The dominant ACK bit must be successfully transmitted, and there must be no dominant bit in the EOF field afterward for the current frame 450 to be valid on bus 40. However, a dominant level in the last EOF bit does not invalidate the currently checked frame 450 but triggers an overload frame. FDL responders 101 ... 10N can send an ACK bit, but this may be disabled instead.Disabling the ACK bit is useful at high bit rates and therefore short bit times, where the signal propagation delay (loop delay) can be several bits long, meaning that a dominant bit sent in the ACK bit slot is only seen in the EOF field of frame 450. With FDL, the receiving station (FDL commander) 100, acting as the receiver, does not send an ACK bit.

[0172] If LCHB mode is activated, and the subscriber station 100 (Commander) is currently the sender of a frame 450 on bus 40, the frame validity check block 155 uses the second frame validity check unit 1552. The second frame validity check unit 1552 determines whether the frame 450, which is currently being sent to bus 40 and therefore transmitted on bus 40, is valid or not.

[0173] The second frame validity check unit 1552 is designed such that the subscriber station 100 (Commander) in LCHB mode as sender accepts a frame 450 as validly sent when the subscriber station 100 (Commander) reaches the sample point AP of the last bit of the EOF field (frame end field).

[0174] Because the participant station 100 (Commander) has disabled function blocks 151 for bus monitoring (bit monitoring) and synchronization in LCHB mode as a transmitter, the participant station 100 (Commander) cannot detect any errors during transmission, i.e., neither bit errors nor format errors nor ACK errors. Nevertheless, the participant station 100 (Commander) must operate in LCHB- R. 416159

[0175] - 31 -

[0176] In sender mode, the device sends a transmission confirmation to the higher protocol layers of the OSI model so that the control software can track the communication process.

[0177] One advantage of this position for the validity check performed by the second frame validity check unit 1552 is that the subscriber station (Commander) in LCHB mode, acting as a sender, reactivates the bus monitoring (bit monitoring) and synchronizations at the sample point of the last bit of the EOF field (frame end field). Therefore, only a minor modification of the circuit is required to confirm the validity of frame 450 at this point in frame 450 in LCHB mode.

[0178] If station 100 (Commander) is not in LCHB mode and is the sender of the current frame 450 on bus 40, station 100 (Commander) expects a response from the receiver with an ACK bit (Need of ACK Response as Transmitter). The receiver of a CAN frame, especially frame 450, which has received the frame without errors up to the CRC-Del bit, confirms this with a dominant bit in the ACK slot. A tolerance is specified for this in case the ACK bit arrives late, for example, due to long bus lines on bus 40, or if the ACK bit takes longer than one bit time, for example, if the ACK bits of several receivers at different distances overlap. Furthermore, according to ISO 11898-1:2024, all EOF bits must be considered recessive. Therefore, the currently checked frame 450 on bus 40 only becomes valid in the last EOF bit. FDL Responder 101 ... 10N can send an ACK bit, but this may also be disabled.In FDL, the FDL-Commander 100, acting as a transmitter, tolerates a missing ACK bit.

[0179] According to Fig. 8, the responder subscriber station 101, in addition to the communication control unit 21 and the transmit / receive unit 22, 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 is designated as R. 416159

[0180] - 32 -

[0181] a computer program (app) may be designed. Such an application is a technical application 261. The application 261 is, for example, a control for a sensor, a transmitter, an actuator, or the like, which is controlled by the application 161 (Fig. 3) of the Commander subscriber station 100 or is intended to provide data for the application 161.

[0182] In addition to the transmitter / receiver device 22, the system ASIC 26 includes a power supply device 27, which supplies the transmitter / receiver device 22 with electrical energy, usually a voltage CAN_Supply, as is known.

[0183] The communication control unit 21 creates a frame 450 in which no bit rate switching or change occurs, and / or evaluates such a frame 450 based on the frame 450 received by the commander subscriber station 100. The communication control unit 21 can also be referred to as an FDL responder. The units 21 and 22 can only send such a frame 450 to bus 40 upon request (polling) from the commander subscriber station 100.

[0184] The transmitter module 222 of Fig. 8 is otherwise constructed in the same way as previously described for the transmitter module 122 of Fig. 3.

[0185] The LRHB mode module 25 of Fig. 8 has at least one function block 251, one configuration block 252, one evaluation block 253, one switching block 254, and one frame validity check block 255. At least one configuration bit 2521, 2522 is stored in the configuration block 252. The at least one function block 251, the configuration block 252, the evaluation block 253, and the switching block 254 each have the same function as previously described for blocks 151, 152, 153, and 154 of the Commander participant station 100.

[0186] Frame validity check block 255 performs a validity check on frames 450 received from bus 40 to ensure that only error-free data packets are forwarded to higher protocol layers of the OSI model (Open R. 416159).

[0187] - 33 -

[0188] Systems Interconnection Model). For this purpose, the framework validity check block 255 according to Annex A of ISO 11898-1:2024 takes precedence.

[0189] Therefore, if the responder station 101 acts as a receiver, the frame validity check block 255 accepts a received frame 450 as valid if the responder station 101, as receiver, has not seen an error up to the last CRC bit.

[0190] However, according to Annex A of ISO 11898-1 :2024, if the responder subscriber station 101 acts as a sender, the frame validity check block 255 does not perform a validity check for frames 450 received from bus 40.

[0191] The LRHB mode module 25 can also deactivate the functions of blocks 151 for frames 450 or messages 45 sent by the subscriber station 101, as previously described with reference to Fig. 3 for the LCHB mode module 15 for frames 450. Accordingly, the LRHB mode module 25 always deactivates synchronization, bus monitoring (bit monitoring), etc., for frames 450 or messages 45 sent by the subscriber station 101 at high bit rates. High bit rates are, for example, greater than 2 Mbit / s.

[0192] Unlike the LCHB mode module 15 of Fig. 3, the LRHB mode module 25 of Fig. 8 is optionally configured to disable synchronization for frames 450 or messages 45 sent by the subscriber station 101 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 2 Mbit / s. This disabling has no significant impact on communication between the commander subscriber station 100 and the respective responder subscriber stations 101 ... 10N.

[0193] This makes it possible to select that the LRHB mode module 25 of Fig. 8 is optionally designed, its synchronization function for frames 450 or messages 45 sent by the subscriber station 101 both at a low as R. 416159

[0194] - 34 - also switches off at a high bit rate, i.e., regardless of the bit rate. In other words, it is selectable that the LRHB mode module 25 of Fig.

[0195] 8 is designed to disable its synchronization function for frames 450 or messages 45 sent by the subscriber station 101, regardless of the bit rate.

[0196] Participating stations 101 ... 10N can do without these synchronizations because no arbitration takes place with FDL and no ACK bit is sent at higher bit rates.

[0197] The LRHB mode module 25 is otherwise constructed in the same way as previously described for the LCHB mode module 15.

[0198] The LCHB mode module 15 and the LRHB mode module 25 thus enable communication with CAN FD Light or FDL even at bit rates greater than or equal to 2 Mbit / s.

[0199] According to a second embodiment, the participant station 100 (Commander) is configured to perform a different validity check for frame 450 in LCHB mode as a receiver than described in the first embodiment.

[0200] The first frame validity check unit 1551 is designed such that the receiving station 100 (Commander) in LCHB mode accepts a frame 450 as valid if the receiving station 100 (Commander), and in particular its first frame validity check unit 1551, does not detect an error until the receiving station 100 (Commander) has received the last bit of the checksum (CRC code) and the checksum (CRC code) is correct. Furthermore, the receiving station 100 (Commander), as the receiver, does not send an acknowledgment response (ACK) in the ACK bit slot. The absence of the acknowledgment response (ACK) in the ACK bit slot is not interpreted as an error by the sender of frame 450.

[0201] Furthermore, participant station 100 (Commander) performs a validity check for frame 450, as previously described for the first embodiment. R. 416159

[0202] - 35 -

[0203] According to a third embodiment, the participant station 100 (Commander) is configured to perform a different validity check for frame 450 in LCHB mode as a receiver than described in one of the preceding embodiments.

[0204] The first frame validity check unit 1551 is configured such that the receiving station 100 (Commander) accepts a frame 450 as valid in LCHB mode if the receiving station 100 (Commander), specifically its first frame validity check unit 1551, detects no error up to the penultimate bit of the EOF field (end of frame field), i.e., bit E0F6. Furthermore, the receiving station 100 (Commander), as receiver, does not send an acknowledgment (ACK) in the ACK bit slot. The sender of frame 450 does not interpret the absence of the acknowledgment (ACK) in the ACK bit slot as an error.

[0205] Furthermore, participant station 100 (Commander) performs a validity check for frame 450, as previously described for the first embodiment.

[0206] According to a fourth embodiment, the participant station 100 (Commander) is configured to perform a different validity check for frame 450 in LCHB mode as a transmitter than described in one of the preceding embodiments.

[0207] The second frame validity check unit 1552 is designed such that the subscriber station 100 (Commander) in LCHB mode as sender accepts or confirms a frame 450 as valid after the subscriber station 100 (Commander) has sent the last bit of the CRC code.

[0208] Furthermore, participant station 100 (Commander) performs a validity check for frame 450, as previously described for the first to third embodiments.

[0209] According to a fifth embodiment, the subscriber station 100 (Commander) is configured to use another R. 416159 as the transmitter in LCHB mode.

[0210] - 36 -

[0211] Validity testing for frame 450 is to be carried out as described in one of the preceding embodiments.

[0212] The second frame validity check unit 1552 is designed such that the subscriber station 100 (Commander) in LCHB mode as sender accepts or acknowledges a frame 450 as valid at the beginning of the bit ACK slot.

[0213] Furthermore, participant station 100 (Commander) performs a validity check for frame 450, as previously described for the first to third embodiments.

[0214] According to a sixth embodiment, the participant station 100 (Commander) is configured to perform a different validity check for frame 450 in LCHB mode as a transmitter than described in one of the preceding embodiments.

[0215] The second frame validity check unit 1552 is designed such that the subscriber station 100 (Commander) in LCHB mode as sender accepts or confirms a frame 450 as valid in the ACK bit slot.

[0216] Furthermore, participant station 100 (Commander) performs a validity check for frame 450, as previously described for the first to third embodiments.

[0217] 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.

[0218] Although the invention has been previously described using the example of the CAN bus system, the invention can be used in any communication network and / or communication method in which two different communication phases are used, in which the bus states R. 416159

[0219] - 37 - can distinguish which are generated for the different communication phases.

[0220] In particular, according to the embodiments, the bus system 1 can be a communication network in which data can be transmitted serially at two different bit rates. It is advantageous, but not a necessary requirement, that the bus system 1 ensures, at least for certain periods of time, exclusive, collision-free access of a participant station 100, 101 ... 10N to a common channel.

[0221] 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 previously. Therefore, to avoid disrupting the arbitration between the participant stations 100 on bus 40, messages 45 from participant stations 101 ... 10N (responders) have an identifier (ID) with a higher priority than the identifier(s) (ID) of participant station 100 or any other CAN FD participant station.

[0222] In particular, there is only one participant station 100 (Commander) and at least one participant station 101 ...10N (Responder), as shown in Fig. 1.

[0223] It is conceivable that at station 100 (Commander), module 15 is arranged separately from the communication control unit 11. It is also conceivable that at at least one of the stations 100, 101 ... 10N (Responders), module 25 is arranged separately from the communication control unit 21.

[0224] It is conceivable that at least one additional subscriber station 100 is connected to bus 40, which is configured to send and / or receive signals using a frame 450. This at least one additional subscriber station 100 can communicate with the Commander subscriber station 100 via R. 416159

[0225] - 38 -

[0226] Arbitration takes place on bus 40. Therefore, at least one additional subscriber station 100 has a communication control unit 11, which is configured to negotiate with the commander subscriber station 100 in the first communication phase 451 of the frame 450 whether the additional subscriber station 100 or the commander subscriber station 100 will receive at least temporary, collision-free access to bus 40 in a subsequent second communication phase 452. Thus, not only FDL communication but also CAN FD communication is possible on bus 40.

Claims

R. 416159 - 39 - Claims 1) Commander subscriber station (100) for a serial bus system (1), comprising a communication control unit (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), in which the bit time (t_bt1) in a first communication phase (451) may differ from a bit time (t_bt2) in a second communication phase (452), a frame validity check block (155) for checking whether a frame corresponding to the received signal (VDIFF; RxD) is equal to a predetermined frame (450) and thus error-free and therefore valid or not, wherein the frame validity check block (155) is configured to perform a first check to the extent that whether the received signal (VDIFF;to execute a second check to determine whether the frame corresponding to the received signal (VDIFF; RxD) is valid or not, if the bit time (t_bt1) of the first communication phase (451) of the predetermined frame (450) has a predetermined value corresponding to a bit rate equal to or less than a predetermined bit rate, wherein the frame validity check block (155) is configured, to execute a second check to determine whether the frame corresponding to the received signal (VDIFF; RxD) is valid or not, if the bit time (t_bt1) of the first communication phase (451) of the predetermined frame (450) has a predetermined value corresponding to a bit rate greater than the predetermined bit rate, and wherein the first check and the second check are at least partially different. 2) Commander participant station (100) according to claim 1, furthermore with R. 416159 - 40 - a first frame validity check unit (1551) for checking the at least one signal (VDIFF; RxD) received from the bus (40), for which the Commander subscriber station (100) is only a receiver but not the sender, up to a first position in the predetermined frame (450) to determine whether a valid frame has been received or not, and a second frame validity check unit (1552) for checking the at least one signal (VDIFF;RxD), for which the Commander subscriber station (100) is the sender, up to a second position in the predetermined frame (450), or to check a signal (TxD) generated on the basis of the predetermined frame (450) and to be sent to the bus (40) to determine whether a valid frame has been sent or not, wherein the frame validity check block (155) performs a check when the first and second frame validity check units (1551, 1552) are not switched on, and wherein the first and second frame validity check units (1551, 1552) are switched on to perform their check when the bit time (t_bt1) of the first communication phase (451) of the predetermined frame (450) has a predetermined value corresponding to the bit rate which is greater than the predetermined bit rate.; 3) Commander participant station (100) according to claim 2, wherein the second position is arranged later in the predetermined frame (450) than the first position. 4) Commander subscriber station (100) according to any of the preceding claims, wherein the Commander subscriber station (100) is a CAN FD subscriber station, and wherein the predetermined frame (450) is a CAN FD frame in the FBFF format. 5) Commander participant station (100) according to one of claims 2 to 4, wherein the first position is one of the following positions, namely the R. 416159 - 41 - Start of the ACK slot bit, the last bit of a checksum (CRC), the penultimate bit of a frame end field (EOF). 6) Commander participant station (100) according to one of claims 2 to 5, wherein the second position is the sampling time of the last bit of a frame end field (EOF). 7) Commander participant station (100) according to one of claims 2 to 6, wherein the second frame validity check unit (1552) is configured to perform its check until the last bit of a checksum (CRC) of the signal (TxD) to be sent to the bus (40) has been sent. 8) Commander participant station (100) according to one of claims 2 to 6, wherein the second frame validity check unit (1552) is configured to perform its check up to the beginning of the ACK slot bit of the signal (TxD) to be sent to the bus (40). 9) Commander participant station (100) according to one of claims 2 to 6, wherein the second frame validity check unit (1552) is configured to perform its check up to the ACK bit slot of the signal (TxD) to be sent to the bus (40). 10) Commander participant station (100) according to one of the preceding claims, further comprising a configuration block (152) in which a value for at least one LCHB mode configuration bit (1521) is stored, indicating whether the bit rate is greater than the predetermined bit rate. 11) Commander subscriber station (100) according to one of the preceding claims, furthermore comprising an LC HB mode module (15) for activating the first and second frame validity check unit (1551 , 1552) when the bit time (t_bt1) of the first communication phase (451) of the predetermined frame (450) has a predetermined value corresponding to the bit rate which is greater than the predetermined bit rate, and for deactivating the first and second frame validity check unit (1551 , R. 416159 - 42 - 1552), if the bit time (t_bt1) of the first communication phase (451) of the predetermined frame (450) has a predetermined value corresponding to the bit rate which is equal to or less than the predetermined bit rate. 12) Commander subscriber station (100) according to claims 10 and 11, wherein the LC HB mode module (15) further comprises an evaluation block (153) for evaluating the value of the at least one LCHB mode configuration bit (1521), and a switching block (154) for activating or deactivating the first and second frame validity check unit (1551, 1552) based on the evaluation of the evaluation block (153). 13) Commander subscriber station (100) according to any of the preceding claims, wherein the predetermined bit rate is 2 Mbit / s. 14) Bus system (1), comprising a bus (40), and at least two subscriber stations (100; 101 ... 10N) which are interconnected via the bus (40) in such a way that they can communicate serially with each other, and one of which subscriber stations is a commander subscriber station (100) according to one of the preceding claims and at least one subscriber station is a responder subscriber station (101 ... 101 N), wherein the responder subscriber station (101 ; 102; ... 101 N) has a communication control device (21) for controlling communication between the responder subscriber station (101 ; 102; ... 101 N) and the commander subscriber station (100) and for evaluating at least one signal (VDIFF; RxD) received from a bus (40) based on the predetermined frame (450), and wherein each of the at least two subscriber stations (100; 101 ...10N) also includes a transmit / receive device (12; 22) for sending a transmit signal (TxD) to the bus (40) and / or for receiving a signal (VDIFF) from the bus (40). R. 416159 - 43 - 15) 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 1 to 13 and a responder subscriber station (101 ... 101 N), wherein the responder subscriber station (101 ; 102; ... 101 N) has a communication control device (21 ) for controlling communication between the responder subscriber station (101 ; 102; ... 101 N) and the 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 the predetermined frame (450).

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