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    • 专利摘要:
    -39- 5 Summary Device for a serial bus system and method for communication in a serial bus system. The device has a reception block for receiving a signal from a bus of the bus system, the signal being based on a transmission signal, and the reception block being designed to receive, in a first phase of communication, a signal having a recessive bus state which can be overwritten by receiving a dominant bus state, having a first reception threshold, and receiving the signal in a second phase of communication, wherein the signal contains bus states other than the recessive and dominant bus states, with a second reception threshold, an evaluation block for evaluating the signal of the bus of the bus system with a switchover receive threshold, and a receive threshold switching block for temporarily switching the receive threshold of the receive block from the first receive threshold 20 to the second receive threshold when the evaluation block with the switchover receive threshold exceeds the bus level for data from the transmission signal in it signal. 2 5 Fig. 6
    公开号:NL2026452A
    申请号:NL2026452
    申请日:2020-09-11
    公开日:2021-04-19
    发明作者:Mutter Arthur；Hartwich Florian
    申请人:Bosch Gmbh Robert；
    IPC主号:
    专利说明:

    Technical field The present invention relates to a device for a subscriber station of a serial bus system and a method for communication in a serial bus system operating at a high data rate and high error resistance. State of the art For communication between sensors and control equipment, for example in vehicles, a bus system is often used where data is sent as messages in the standard IS011898-1: 2015 as CAN protocol specification with CAN FD. The messages are sent between the bus subscribers of the bus system, such as sensors, control units, encoders, etc. In order to be able to send data with a higher bit rate than with CAN, the CAN FD message format has an option for switching to a higher bit rate within a message provided. With such techniques, the maximum possible data rate is increased to values above 1MBit / s by using a higher clock rate in the range of the data fields. Such messages are also referred to below as CAN FD frames or CAN FD messages.
    Devices for communication with CAN FD are currently in the introduction phase for vehicles. Most manufacturers use CAN FD in the first step with a data bit rate of 2 Mbit / s and one
    -2- arbitrage bitrate of 500 kbit / s in the vehicle. In addition, with CAN FD, the useful data length has been expanded from 8 to a maximum of 64 bytes and the data transmission rates are significantly higher than with CAN.
    For an even higher data bit rate and useful data length in a message, a successor to the bus system for CAN FD is currently under development, which will be referred to as CAN XL hereinafter. In addition to pure data transport via the CAN bus, CAN XL must also support other functions, such as functional safety, data security and Quality of Service (QoS). These are basic properties that are required in an autonomous driving vehicle. CAN XL should also offer the advantages of arbitration of a CAN or CAN FD based communication network, according to which only one subscriber station in the data phase has exclusive, collision-free access to the bus of the bus system. This offers many advantages with regard to, for example, the error-resistance of communication. In arbitration, there are recessive and dominant bus levels on the bus, where the dominant bus level can override a recessive bus level. Because the recessive and dominant bus levels are driven differently, the bus levels are distorted asymmetrically on the bus. As a result, the recessive and dominant bus levels can only be used for robust data transmission up to a certain data transmission speed, If the data bit rate for CAN XL is higher or higher, i.e. faster than for CAN FD, then there are no recessive and dominant bus levels more in the data phase with CAN XL. Instead, other bus levels are used in the data phase, hereinafter referred to as Data_0 and Data_1. Thus, for a transmitting / receiving device (transceiver) with CAN XL, the operating mode for generating the bus level in the arbitration phase and the operating mode for generating the bus level in the data phase are different.
    This has the major drawback for the transmitting / receiving device (transceiver) in the CAN XL data phase that a first transmitting / receiving
    -3- device of the bus system that has switched to the data phase mode, cannot reliably recognize the level of a second transmit / receive device that has switched to the arbitration mode. In addition, the second transmitting / receiving device of the bus system switched to the arbitration phase operation mode cannot reliably detect the level of the first transmitting / receiving device switched to the data phase operation mode.
    In normal communication there is no problem if all the subscriber stations in the bus system switch their transceivers at the same time, apart from transit times via the bus. However, if one subscriber station of the bus system is turned on while the other subscriber stations are transmitting at least one CAN XL frame, the newly incoming subscriber station cannot clearly identify an idle state (Idle) at the end of a frame. Therefore, such a participant station cannot be properly integrated. The same applies for a subscriber station that is switched to a protocol exception state in accordance with IS011898-1: 2015 to tolerate a transmission of a frame in the bus system for which the subscriber station is not designed. The same also applies to a subscriber station that has lost the connection due to bit errors. This leads to communication errors and thus to a reduction in the transferable net data rate.
    Disclosure of the Invention It is therefore an object of the present invention to provide a device for a subscriber station of a serial bus system and a method of communication in a serial bus system which solves the aforementioned problems. In particular, a device for a subscriber station of a serial bus system and a
    -4- method of communication in a serial bus system, in which with great flexibility in the operation of a technical installation, in which the bus system is used for communication, and with great error robustness of the communication, a high data rate and an increase in the amount useful data per frame can be realized. The object is achieved by a device for a subscriber station of a serial bus system having the features of claim 1. The device has a reception block for receiving a signal from a bus of the bus system, the signal being based on a transmission signal that transmits a message. is exchanged between subscriber stations of the bus system, and the receive block is designed to receive the signal in a first communication phase in which in the signal a recessive bus state can be overwritten by a dominant bus state, to be received with a first receive threshold, and the signal in a second communication phase in which the signal contains bus states other than the recessive and dominant bus states, with a second receive threshold to be received, an evaluation block for evaluating the signal from the bus of the bus with a switchover receive threshold different from the first receive threshold and the second inc capture threshold, and a receive threshold switching block for temporarily switching the reception threshold of the reception block from the first reception threshold to the second reception threshold when the evaluation block with the switching reception threshold in the signal recognizes the bus level for Data_1 of the transmission signal.
    Due to the design of the device, a subscriber station of the bus system that is switched on while the other subscriber stations are sending CAN XL frames, can automatically integrate into an ongoing communication.
    The device can clearly identify the idle state (Idle) so that the subscriber station can be properly integrated into the communication without any problems. This allows the device to enter the subscriber station
    -5- automatically switch to the operating mode that is correct for the current operating state on the bus. This allows the subscriber station to correctly recognize the current bus level.
    The advantage of the device described is that a transmitting / receiving device of the subscriber station automatically adjusts itself to the correct reception threshold with the aid of an easily recognizable switching condition, which requires little effort in the hardware.
    The described arrangement offers the same advantages for subscriber stations that switch to the protocol exception state in accordance with ISO11898-1: 2015 or lose the connection due to bit errors.
    This makes it possible to actively drive the two bus states in a frame in the data phase without losing the robustness of the bus system in the data phase. The device thus makes an important contribution to the fact that the net data rate in the bus system can be increased.
    As a result, the described device prevents the subscriber station of the bus system from disturbing or interrupting any other subscriber station with an error frame just because the integration into the ongoing communication has failed.
    Therefore, with the device, which is in particular a receive block or a transmit / receive device, the reception of the frames with a low error rate can be guaranteed even if the amount of usable data per frame increases. This means that the communication in the serial bus system can also be performed with high error resistance when there is a high data rate and an increase in the amount of user data per frame.
    Therefore, with the device in the bus system, it is especially possible to maintain an arbitration known from CAN in a first communication phase and yet significantly increase the transmission speed compared to CAN or CAN FD.
    This helps to achieve a net data rate of at least 5 Mbit / s to approximately 8 Mbit / s or 10 Mbit / s or higher. At a transmission speed of 10 Mbit / s, one bit is less than 100 ns long. In addition, the size of the useful data in the bus system can be up to 4096 bytes per frame. The method performed by the device can also be used if at least one CAN FD tolerant CAN subscriber station is in the bus system, which is designed in accordance with the ISO 11898-1: 2015 standard, and / or there is at least one CAN FD participant station is present that sends messages according to the CAN protocol and / or CAN FD protocol. Advantageous further embodiments of the device are given in the dependent claims.
    According to an exemplary embodiment of the invention, the reception threshold switching block is designed to temporarily switch from the reception block's reception threshold to the reception block's second reception threshold and thereby switch it to an operating mode different from three other operating modes of the device, where the three other operating modes of the device include: a first operating mode for sending and / or receiving the signal in the first communication phase, a second operating mode for receiving the signal only in the second communication phase and a third operating mode for sending and receiving the signal in the second communication phase.
    According to an exemplary embodiment of the invention, the reception threshold switching block is designed to temporarily switch the reception threshold of the reception block from the first reception threshold to the second reception threshold in a first operating mode in which reception of the signal is performed in the first communication phase. It is conceivable that the evaluation block is a comparator which has an input for connection to two bus lines of the bus, and the output of which is connected to the receive threshold switching block.
    Possibly, the evaluation block is designed to check whether a bus level switchover receive threshold for Data_1 is subscribed to by the transmission signal. Here, the switch receive threshold can be a receive threshold with a negative numerical value. According to a special embodiment, the bus states of the signal received from the bus in the first communication phase are generated with a different Physical Layer than the bus states of the signal received in the second communication phase. According to a further special embodiment variant, the bus states of the signal received from the bus in the first communication phase have a longer bit time than the bus states of the signal received in the second communication phase. Possibly, in the first communication phase, it is negotiated which of the subscriber stations of the bus system in the next second communication phase will have at least temporarily exclusive, collision-free access to the bus.
    The device may also have a transmission block for transmitting messages on a bus of the bus system, the transmission block being designed to switch between a transmission mode for the first communication phase and a transmission mode when transmitting the different communication phases of a message for the second communication phase. The described device may be part of a subscriber station of a serial bus system which further has a communication control device for controlling communication between the subscriber station and at least one other subscriber station of the bus system.
    Here, there is the possibility that the communication controller is designed to switch the device into an operating mode for sending and / or receiving the signal in the first phase of communication when the communication controller has recognized an idle state on the bus.
    The subscriber station described above may form part of a bus system which also comprises a bus and at least two subscriber stations which are connected to each other via the bus in such a way that they can communicate with each other serially. At least one of the at least two subscriber stations is a subscriber station described above.
    In addition, the above object is achieved by a method of communication in a serial bus system according to claim 14. The method is carried out with a device having a receive block for receiving a signal from a bus of the bus system, an evaluation block and a receive threshold switching block, wherein the device performs the steps of receiving, with the receive block, a signal from the bus based on a transmission signal, with which a message is exchanged between subscriber stations of the bus system, wherein the
    29. receive block is arranged to receive the signal in a first communication phase, in which a recessive bus state in the signal can be overwritten by a dominant bus state, with a first receive threshold, and that signal in a second communication phase, in which the signal contains other bus states than the recessive and dominant bus states, to be received with a second receive threshold, of evaluation, with the evaluation block, of the signal from the bus of the bus system having a switchover receive threshold different from the first receive threshold and the second receive threshold, and temporarily switch, with the reception threshold switching block, the reception threshold of the reception block from the first reception threshold to the second reception threshold, if the evaluation block with the switching reception threshold in the signal recognizes the bus level for Data_1 of the transmission signal.
    The method offers the same advantages as mentioned above with regard to the device and / or the subscriber station. Further possible implementations of the invention also include combinations not explicitly mentioned of features or embodiments described above or below with respect to the exemplary embodiments. Those of skill in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.
    Drawings The invention is described in more detail below with reference to the accompanying drawings and with the aid of exemplary embodiments. They show: Fig. 1 shows a simplified block diagram of a bus system according to a first embodiment;
    -10- Fig. 2 shows a diagram illustrating the structure of messages that can be transmitted by a transmitting / receiving device for a subscriber station of the bus system according to the first exemplary embodiment;
    FIG. 3 shows a simplified schematic block diagram of a subscriber station of the bus system according to the first exemplary embodiment; FIG. 4 shows a time profile of bus signals CAN-XL H and CAN-XL Lin the arbitration phase on a bus of the bus system according to the first embodiment; FIG. 5 shows a time profile of a differential voltage VDIFF resulting from the bus signals CAN-XL H and CAN-XL L of FIG. 4;
    FIG. 6 shows a time profile of bus signals CAN-XL H and CAN-XL Lin the data phase on a bus of the bus system according to the first embodiment; FIG. 7 shows a time profile of a differential voltage VDIFF resulting from the bus signals CAN-XL H and CAN-XL L of FIG. 6; FIG. 8 shows a time profile of a differential voltage VDIFF, which arises on the basis of the bus signals CAN-XL._H and CAN-XL L for an extract from the arbitration phase and from the data phase according to the first embodiment; FIG. 9 shows a state diagram for the operating states of the transmitting / receiving device according to the first embodiment; and FIG. 10 shows a state diagram for the operating states of the transmitting / receiving device according to a second embodiment.
    In the figures, identical or functionally identical elements are provided with the same reference symbols, unless otherwise indicated.
    Description of the embodiments
    FIG. 1 shows, by way of example, a bus system 1 which is especially designed fundamentally for a CAN bus system, a CAN FD bus system, a CAN XL 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.
    In Figure 1, the bus system 1 has a number of subscriber stations 10, 20, 30, each of which is connected to a bus 40 with a first bus line 41 and a second bus line 42. The bus lines 41, 42 can also be CAN_H and CAN Lor CAN-XL H and CAN-XL_L and serve for electrical signal transmission after coupling in the differential level or dominant level or generating recessive levels for a signal in the transmission state.
    Via the bus 40, messages 45, 46 in the form of signals can be serially transmitted between the individual subscriber stations 10, 20, 30.
    Subscriber stations 10, 20, 30 are, for example, control devices, sensors, display devices, etc. of a motor vehicle.
    If an error occurs during communication on bus 40, as indicated by the jagged black block arrow in Fig. 1, an error frame 47 (error flag) can be sent.
    Error frame 47 consists of six dominant bits.
    All other subscriber stations 10, 20, 30 recognize these six consecutive dominant bits as a format error or as a violation of the bit padding rule, which determines that an inverse bit is inserted into a message 45, 46 after five identical bits must be inserted.
    -12- An error-free message 45, 46 is acknowledged by the receivers with an acknowledgment bit, which is a dominant bit sent in an acknowledgment time slot sent recessively by the sender.
    Apart from the acknowledgment period, the sender of a message 45, 46 expects to always see the level on bus 40 that he is sending himself.
    Otherwise, the sender recognizes a bit error and considers message 45, 46 invalid.
    Failed messages 45, 46 are repeated.
    As shown in Figure 1, the subscriber station 10 has a communication control device 11, a transmit / receive device 12, and an operating mode setting device 15. In contrast, the subscriber station 20 has a communication control device 21 and a transmit / receive device 22. The subscriber station 30 has a communication control device 31, a transmit / receive device 32 and an operating mode setting device 35. The transmitting / receiving devices 12, 22, 32 of the subscriber stations 10, 20, 30 are each directly connected to the bus 40, even if this is not is illustrated in Figure 1. The communication controllers 11, 21, 31 each serve to control the communication between the respective subscriber station 10, 20, 30 via the bus 40 with at least one other subscriber station of the subscriber stations 10, 20, 30, which are connected to the bus 40. The communication controller 11 creates and reads first messages 45,
    which are, for example, modified CAN messages 45.
    Here, the modified CAN messages 45 are structured on the basis of a CAN XL format, which is described in more detail with reference to Figure 2. The communication control device 21 may be designed as a conventional CAN controller according to ISO 11898-1: 2015. The communication controller 21 creates and reads second messages 46, for example classic CAN messages 46. The classic CAN messages 46 are
    -13- structured according to the classic basic format, in which the message 46 can contain a maximum of 8 data bytes. can.
    Alternatively, the classic CAN message 46 is structured as a CAN FD message, which can include a number of up to 64 data bytes, which are also sent at a significantly higher data rate than the classic CAN message 46. In the latter case, the communication control device 21 designed as a conventional CAN FD controller.
    The communication control device 31 can be designed to support a CAN
    XL message 45 or a classic CAN message 46 for the transmitting / receiving device 32 to be made available or to receive from it.
    The communication controller 31 thus creates and reads a first message 45 or a second message 46, the first and second messages 44, 46 differing in their data transmission standard, namely CAN XL or CAN in this case.
    Alternatively, the classic CAN message 46 is structured as a CAN FD message.
    In the latter case, the communication controller 31 is designed as a conventional CAN FD controller.
    The transmitting / receiving device 12 can be designed as a CAN
    XL transceiver, apart from the differences described in more detail below.
    The transmitting / receiving device 22 can be designed as a conventional CAN transceiver or CAN FD transceiver.
    The transmitting / receiving device 32 can be designed to make messages 45 in accordance with the CAN XL format or messages 46 in accordance with the current CAN basic format available to the communication control device 31 or to receive them from them as required.
    The transmitting / receiving devices 12, 32 may additionally or alternatively be designed as a conventional CAN FD transceiver.
    -14 - With the two subscriber stations 10, 30 it is possible to create messages 45 with the CAN XL format and then send and receive such messages 45.
    FIG. 2 shows a CAN XL frame 450 for the message 45 as transmitted from the transceiver 12 or the transceiver 32. The CAN XL frame 450 is divided for CAN communication on the bus 40 into different communication phases 451 to 453, namely an arbitration phase 451, a data phase 452 and a frame end phase 453. Between two different frames 450, an inactive or standby state (Idle or standby) 410 on the bus 40 in which none of the subscriber stations 10, 20, 30 transmit anything on the bus 40. The idle or standby state (Idle or standby) 410 is referred to briefly below as the idle state 410.
    In the arbitration phase 451, an identifier is used to negotiate bitwise between the subscriber stations 10, 20, 30 which subscriber station 10, 20 30 wants to send the message 45, 46 with the highest priority and therefore gets exclusive access to the bus the next time before transmission. 40 of the bus system 1.
    In the data phase 452 the useful data of the CAN-XL frame or message 45 is sent. Depending on the range of values of a data length code, the useful data may have, for example, up to 4096 bytes or greater value. In data phase 452, only one of the subscriber stations 10, 20, 30 is the transmitter of a frame 450, as described above, in normal operation. Therefore, all other subscriber stations 10, 20, 30 are receivers of the frame 450 and are therefore switched to a receive mode.
    For example, in the frame end phase 453, a checksum may be included in a checksum field on the data of the data phase 452 including the stuff bits, which are extracted from the transmit block of the message 45 after a predetermined
    -15 - number of identical bits, in particular 10 or other number of identical bits, are inserted as inverse bit. In addition, at least one acknowledge bit may be included in an end field in the frame end phase 453. In addition, there may be a sequence of 11 identical bits indicating the end of the CAN XL frame 450. With the at least one acknowledge bit, it can be communicated whether or not a receive block has detected an error in the received CAN XL frame 450 or message 45, as already mentioned.
    In the arbitration phase 451 and the frame end phase 453, a physical layer is used as in CAN and CAN-FD. The physical layer corresponds to the bit transmission layer or layer 1 of the well-known OSI (Open Systems Interconnection Model) model.
    An important point during phases 451, 453 is that the well-known CSMA / CR method is used, whereby the subscriber stations 10, 20, 30 can simultaneously access bus 40 without destroying the higher priority message 45, 46. As a result, further subscriber stations 10, 20, 30 can be added to the bus system 1 relatively easily, which is very advantageous.
    The CSMA / CR method results in so-called recessive states on the bus 40, which can be overwritten by other subscriber stations 10, 20, 30 with dominant states on the bus 40. In the recessive state, prevailing on the individual subscriber stations 10, 20, 30 conditions with high resistance, which in combination with the parasites of the bus circuit leads to longer time constants. This leads to a limitation of the maximum bit rate of the current CAN FD-Physical layer to currently approximately 2 megabits per second in real vehicle use.
    A transmission block of the message 45 only begins to transmit bits of the data phase 452 on bus 40 when the subscriber station 10 if the. transmission block has won the arbitration and the subscriber station 10 if
    The transmission block thus has exclusive access to the bus 40 of the bus system 1 for transmission.
    In general, the following properties deviating from CAN or CAN FD can be implemented in the bus system with CAN XL:
    a) Adoption and, if necessary, adaptation of proven properties responsible for robustness and user-friendliness of CAN and CAN FD, in particular frame structure with identifier and arbitration according to the CSMA / CR method,
    b) increase the net data transmission rate to about 10 megabits per second, ¢) increase the User data per frame to about 4kbyte.
    FIG. 3 shows the basic structure of the subscriber station 10 with the communication controller 11, the transmit / receive device 12 and the operating mode setting device 15. The operating mode setting device 15 has an evaluation block 151 and a receive threshold switching block 152. The subscriber station 30 is constructed in a similar manner. , as shown in FIG. 3, except that the operating mode setting device 35 is not integrated in the transceiver 32, but is separately provided with the communication controller 31 and the transceiver 32. Therefore, the subscriber station 30 and the operating mode setting device 35 are not described separately.
    The functions of the device 15 described below are identical in the device 35.
    According to FIG. 3, the subscriber station has, in addition to a communication control device 11, the transmit / receive device 12 and the operating mode setting device 15, a microcontroller 13, to which the communication control device 11 is assigned, and a system ASIC 16 (ASIC = application-specific integrated circuit). ), which may alternatively be a System Basic Chip (SBC), running multiple for an electronic
    _17 assembly of the participant station 10 necessary functions are summarized. In addition to the transmitting / receiving device 12, an energy supply device 17 is installed in the ASIC 16 system, which supplies the transmitting / receiving device 12 with electrical energy. The power supply device 17 usually supplies a voltage CAN_ Supply of 5 V. However, depending on the need, the power supply device 17 can supply a different voltage with a different value. In addition or as an alternative, the energy supply device 17 can be designed as a power source.
    The transmitting / receiving device 12 also has a transmit block 121 and a receive block 122. Even if the transmitting / receiving device 12 is always referred to below, it is also possible to have the receive block 122 in a separate device external to the transmission block 121 The transmission block 121 and the receive block 122 may be constructed as in a conventional transmission / reception device 22. In particular, the transmission block 121 may have at least one operational amplifier and / or one transistor. In particular, the receive block 122 may have at least one operational amplifier and / or one transistor.
    The sending / receiving device 12 is connected to the bus 40, more precisely its first bus line 41 for CAN_H or CAN-XL_H and its second bus line 42 for CAN_L or CAN-XL_L. The supply voltage for the energy supply device 17 for supplying the first and second bus lines 41, 42 with electrical energy, in particular the CAN supply voltage, takes place via at least one connection 43. The connection to ground or CAN_GND is realized via a connection 44 The first and second bus lines 41, 42 are terminated with a terminating resistor
    49.
    The first and second bus lines 41, 42 are connected in the transmitting / receiving device 12 not only to the transmission block 121, also called a transmitter, and to the receive block 122, also known as the
    A receiver is mentioned even if the connection is not shown in Figure 3 for simplicity. The first and second bus lines 41, 42 are also connected in the transmitting / receiving device 12 to the device 15.
    When the bus system 1 is in operation, the transmitting block 121 can transmit a transmission signal TXD or TxD from the communication control device 11 with digital states 0 and 1, as schematically shown in FIG. 3, convert into corresponding signals Data_0 and Data_1 for the bus lines 41, 42 and send these signals Data_0 and Data_1 on the terminals for CAN _H and CAN _L or CAN-XL_H and CAN-XL_L on bus 40, as shown in figure 4. It receive block 122 forms a differential voltage VDIFF in accordance with the bus signals received from bus 40 on CAN-XL H and CAN-XL_L according to Fig. 5 and converts it into a received signal RXD or RxD with digital states 0 and 1, as schematically illustrated in FIG. 3, and forwards it to the communication control device 11, as shown in FIG. 3. With the exception of the idle state 410, the transmitting / receiving device 12 with the receive block 122 always listens during normal operation for a transmission of data or messages 45, 46 on the bus 40, regardless of whether the transmitting / receiving device 12 is or not. the transmission block of the message is 45.
    According to Figure 4, the signals on CAN-XL H and CAN-XL Lin have the above communication phases 451, 453 have the dominant and recessive bus levels 401, 402 as known from CAN. In contrast, the CAN-XL H and CAN-XL L signals in data phase 452 differ from the conventional signals on CAN_H and CAN_L, as described in more detail below with reference to FIG. On the basis of the signals CAN-XL H and CAN-XL L from figure 4, a difference signal VDIFF = CAN-XL H - CAN-XL_L is formed on bus 40, which is shown in figure 5. The bits of the difference signal VDIFF have a bit duration t_bt1.
    As can be seen in Fig. 4, the transmission block 121 only controls the dominant states 402 of the differential signals CAN-XL_H, CAN-XL_L in the above communication phases 451, 453 differently. In addition, the bus levels on the bus 40 for the recessive states 401 in the above communication phases 451, 453 are equal to half the voltage Vce or CAN supply of, for example, about 5V, so 2.5 V. In the recessive state 401, the bus level is not controlled by the transmission block 121; it is set by the termination resistor 49. The bus levels on bus 40 for the dominant states 402, on the other hand, are about 1.5 V for the signal CAN_XL and 3.5 V for the signal CAN_XL_H. Accordingly, in the example of Figures 4 and 5, a differential voltage VDIFF between about 0V and 2V is established. So for a voltage VDIFF = CAN-XL_H - CAN-XL_L for the recessive states 401 (logic "1" of the transmission signal TxD) a value of approximately 0 V and for the dominant states 402 results (logic "0" of the transmission signal TxD) ) a value of about 2.0 V. The state change between states 401, 402 can be recognized by the receive block 122 in phases 451, 453 using a receive threshold T_a, which is shown in FIG. 5. In the example of FIG. 5, a receive threshold T_a of receive block 122 is set to about 0.7V. In a conventional transceiver module more specifically a module of a transceiver device 12, the receive threshold is in a tolerance range between T_a_min and T_a_max, depending on the operating temperature, operating voltage and manufacturing tolerance.
    FIG. 6 and FIG. 7 show comparable time courses to FIG. 4 and FIG. 5 for the data phase 452. Accordingly, transmission block 121 drives the bus states U_D0, U_D1 of the differential signals CAN-XL_H, CAN-XL_L in the data phase 452 each differently.
    In general, according to FIG. 8 a differential voltage VDIFF between a maximum of 0.05 V = VDIFF 401 max for recessive states 401 in the
    -20 communication phases 451, 453 at the receiver of the frame 450 and at least 1.5 V = VDIFF 402 min for dominant states 402. In addition, according to Figure 8, in general, in the switch block 152, the receive threshold T_a of the receive block 122 is between a minimum receive threshold T_a_min of 0.5 V and a maximum receive threshold
    T_a_max of 0.9 V.
    The value of the reception threshold T_a is adjusted depending on the manufacturing tolerances and the influence of temperature and operating voltage.
    Thus, if the differential voltage VDIFF is less than 0.5 V, as shown by way of example in the left part of Fig. 8, the bus level VDIFF_401 is reliably read as "recessive". If the differential voltage VDIFF level is higher than 0.9 V, the bus level is safely read as dominant.
    If the differential voltage VDIFF level is between 0.5V and 0.9V, the level cannot be reliably identified as "recessive" or
    "dominant". When the transmitting / receiving device 12, in particular its device 15, recognizes the end of the arbitration phase 451, the transmitting / receiving device 12, 22, 32 in the subscriber stations 10, 20, 30 of the bus system 1 is switched to the corresponding mode of operation for the data phase 452, as will be explained in more detail later with reference to FIG. Fig. 9 8 show in its right part the differential voltage VDIFF, which is formed from the signals Data_0 and Data_1, which the transmission block 121 sends to the bus 40 in the operating mode of the data phase 452. The bus levels on bus 40 for the Data_0 states are in the example of Figures 6 to 8 at about 3 V for the signal CAN_XL H and 2 V for the signal CAN_XL L.
    The bus levels U_D1 on the bus 40 for the Data_1 states in the data phase 452 are approximately 2 V for the signal CAN_XL H and 3 V for the signal CAN_XL_L.
    A differential voltage VDIFF of +/- 1 V would also be possible with other bus levels.
    However, the 3V and 2V levels according to Figure 6 are symmetrical with respect to the medium voltage of 2.5V at
    -21- an operating voltage of 5V. The symmetry is beneficial for reducing emissions that degrade the quality of the signals on the bus 40. According to the right-hand part of Fig. 8, in the optionally faster data phase 452 for the bus states Data_9, Data_1, the bus states U_D0, U_D1 or the differential voltages VDIFF_D0, VDIFF_D1 according to the binary data states O and 1 of the transmission signal TXD occur. The minimum differential voltage VDIFF_D0_min for Data_0 bits expected by the receiver in data phase 452 is about 0.6 V in the example of Figures 6 to 8. The maximum differential voltage VDIFF_D1_ max for Data_1 bits is in the example of FIG. 6 to 8 in data phase 452 at approximately 0.6 V.
    For this purpose, the transmission block 121 controls the states of the differential signals CAN-XL_H, CAN-XL L differently again, as in the above communication phases 451, 453. The two bus states U_D0, U_D1 or the differential voltages VDIFF_DO, VDIFF_D1 in data phase 452 become however, driven symmetrically in accordance with data states 0 and 1 of the transmission signal TXD. In addition, the bus levels for the data states Data_0 in the communication phases 451, 453 differ from the data states Data_0 in the communication phase 452. In addition, the bus levels for the data states Data_1 in the communication phases 451, 453 differ from the data states Data_1 in communication phase 452.
    In the data phase 452, the receive block 122 uses, in addition to the receive threshold T_a of the phases 451, 453, a receive threshold T_d which is nominally about 0.0 V and thus between the maximum value of T dmax = 0.1 Ven the minimum value from T d min = -0.1 V. The value of the reception threshold T_d is set depending on the manufacturing tolerances and the influence of temperature and operating voltage.
    222- The nominal differential voltage for the recessive data state, VDIFF 401, is 0V in the range between T_d max and T d min and therefore cannot be clearly identified when the receive threshold T_d is used. However, the nominal differential voltage for the recessive data state, VDIFF_401, can be recognized with the receive threshold T_a. The minimum differential voltage for the data state Data_0, VDIFF_DO_min, is lower than T_a_max and therefore cannot be clearly identified when the receive threshold T_a is used. However, the minimum differential voltage for the data state Data_0, VDIFF_D0_min can be recognized with the receive threshold T_d.
    In addition, the receive block 122 may also use a receive threshold Tc in the data phase 452, which is about -0.4V. To this end, the operating mode setting device converts the reception threshold T_a previously used only in phases 451, 453 and the reception threshold T_d previously used only in phase 452 for the reception block 122 to the three reception thresholds T_a, T_d, T_c or, depending on an evaluation of the reception threshold. T_c, adds one of the receive thresholds T_a or T_d, as described in more detail in Fig. 9.
    For example, even if the numerical value for the receive threshold T_c is 0.4 V, the numerical value can be optimized depending on the CAN bus topology used.
    Thus, the transmit block 121 is switched from a first operating mode in phases 451, 453 to another operating mode in data phase 452, as explained in more detail with reference to Figs. 9. In the first mode of operation, the bits have bit time t_bt1 and there are dominant and recessive bus states or bus levels. In one mode of operation of the data phase 452, the bits have a bit time t_bt2 and there are no dominant and recessive bus states or bus levels, but instead the bus levels Data_0
    223 - and Data_1. The bit time t_bt2 may be shorter than the bit time t_bt1, as shown in Fig. 6. Optionally, the bit time t_bt2, t_bt1 are the same. In other words, in a first mode of operation, the transmission block 121 generates, according to Figure 4, Figure 5 and the left part of Figure 6, a first data state, for example 0, of the transmission signal TxD as bus state 402 with different bus levels for two bus lines 41, 42 of bus 40 and a second data state, and a second data state, for example 1, of the transmission signal TxD as bus state 401 with the same bus level for the two bus lines 41, 42 of bus 40. In addition, for the time characteristic of the signals CAN- XL_H, CAN-XL_L in an operating mode including the data phase 452, the first and second data status 0, of the transmission signal TxD at least partially on, so that the bus levels Data_0, Data_1 of the right part of Fig. 6 for the two bus lines 41, 42 of bus 40 can be formed. The difference between the Physical Layer of CAN in the communication phases 453, 451 and the previously described Physical Layer in the data phase 452 is that the states Data_1 with the differential voltage VDIFF_D1 in the data phase 452 are partially to fully controlled by the transmission block 121 or the transmitting / receiving device 12. At a bit rate of, for example, 10 Mbit / s in the data phase 452, a bit rate is t_bt2 = 100 ns.
    Thus, the bit time t_bt2 in the data phase 452 in the example shown in Figure 6 is shorter than the bit time t_bt1 used in the arbitration phase 451 and the frame end phase 453. Therefore, in the data phase 452 transmission takes place. location at a higher bit rate than in the arbitration phase 451 and the frame end phase
    453. In this way, the transmission speed in bus system 1 can be increased even further than with CAN FD.
    -24- FIG. 9 illustrates in a diagram the switching of the receive block 122 between the communication phases 451, 453, in which a "slow operation mode" B_451 or "Slow-Mode" is optionally used, and the communication phase 452 in which a "fast operation mode" or a "Fast-mode" is used. -Mode ”is used, as explained in more detail below. In addition, the transmit / receive device 12 can be switched to a configuration operating mode B_420, as illustrated with a switchover condition S20 on an arrow between operating mode B_451 and operating mode B_ 420.
    In the configuration mode B_420, at least one setting for communication can be made, such as setting the numerical values for the reception thresholds T_a, T_d, T_c, setting the numerical values for time periods used in the communication in the bus system 1, at at least one IDs are set, or other settings. The downshifting state S21 from the operating mode B_420 to the operating mode B_451 may be that the transmission signal TxD is constant for a predetermined time t of, for example, greater than 5 µs, as illustrated by a downshifting condition S21 on the arrow between the operating modes B_420, B_451. The switch-back condition S21 has the effect that the subscriber station 10 can safely participate again in the communication in the bus system 1 after the predetermined time t. In the communication phase 452 there are three different operating modes for the transceiver 12, more precisely the reception block 122, namely the operating mode B_452_RX, operating mode B _ 452 TX and operating mode B_452 RX_A. This operating mode is only provided for a subscriber station 10, 20, 30 that does not know in which phase the CAN bus 40 is currently being operated and that would like to be integrated into the communication. This is described in more detail below.
    225- To detect the need to switch between the operation modes 451, 452 RX, 452_TX, 452 RX_A, as illustrated in Fig. 9, the operation mode setting device 15, more precisely its evaluation block 151, can be used. The evaluation block 151 can be designed as a comparator. The measurement result of the evaluation block 151 is meaningfully low-pass filtered, so that the switchover by means of the block 152 of the operating mode setting device 15 is not accidentally triggered by overshoots or reflections.
    The receive threshold switching block 152 is equipped, based on the evaluation result of the evaluation block 151, to decide to which of the operating modes 451, 452 RX, 452_TX, 452 RX_A the receive block 122 is to be switched.
    The receive threshold switching block 152 switches from the operating mode B_451 to the operating mode B_452_ RX if, in the normal operation of the subscriber station 10, the end of the arbitration phase 451 for a CAN-XL frame 450 was recognized if the subscriber station 10 has not won the arbitration. In this case, the transceiver 12 can only act as a receiver in the next data stage 452. Alternatively, the transmit / receive device 12 in the next data stage 452 in operating mode B_452_TX functions as both a transmitter and a receiver of a frame. 450 if the participant station 10 has won the arbitration.
    As a result, regardless of whether the subscriber station 10 has lost or won the arbitration, the transmit / receive device 12, in particular the receive block 122, of the operating mode B_451, in the signals of FIG. 4 or the left side of Fig. 6 are displayed for data phase 452 switched to operating mode B_452_RX. Thus, the subscriber station 10 changes from the operating mode B_451 to the operating mode B_452_RX, as illustrated by the arrow S1 in Fig. 9. Accordingly, the receive threshold switching block 152 turns on the receive threshold T_d, instead of
    26 - the reception threshold T_a, as already mentioned with reference to Figures 4 to 6. If the participant station 10 has lost the arbitration, the transmission block 121 is also de-activated or locked so that no signals are sent on the bus 40, since the participant station 10 is only acts as a receiver of the frame 450. If the subscriber station 10 has not lost the arbitration, but has won, then the transmitting / receiving device 12, especially the transmitting block 121, is switched from the operating mode B_452 RX for the data signal. phase 452 to operating mode B_452 TX. Thus, the subscriber station 10 changes from the operating mode B_452 RX to the operating mode B_452 TX, as illustrated by the arrow S2 in Fig. 9. Thus, the transmission block 121 sends signals according to the right part of Fig. 6 on the bus 40. In addition, the receive block 122 receives the signals. from the bus 40, as in the operating mode B_452_RX and as already mentioned above. The receive threshold switching block 152 switches from the operating mode B_452 TX back to the operating mode B_451 if one of the following three cases is present, as illustrated by the downshift conditions S3_1, S3_2, S3_3 on the arrow between the operating modes B_ 452 TX, B_451. The downshift state S3_1 is present when the subscriber station 10, for example, the evaluation block 151, detects in the operating mode B_452 TX that the data phase 452 has ended. The downshift condition S3_2 is present when the received signal RxD contains too long a series of identical bits, for example, an error frame 47 has been received or no fill bit has been incorrectly inserted into frame 450.
    The downshift condition S3_2 is present when the transmitting / receiving device 12 detects that at least one other of the
    227 subscriber stations 20, 30 during the data phase 452 has sent something to the bus 40, so that there is no more exclusive, collision-free access to the bus 40 and a collision occurs on bus 40.
    In addition, the receive threshold switching block 152 switches from the operating mode B_452_RX back to the operating mode B_451 if one of the following two cases is present, such as the downshift conditions S4_1, S4_2 on the arrow between the operating modes B_452_RX, B_451.
    The downshift state S4_1 is present when the subscriber station 10, for example, the evaluation block 151, recognizes in the operating mode B_452_RX that the data phase 452 has ended.
    The downshift condition S4_2 is present when the transmit block 121 again transmits something on the bus 40 after the end of the data phase 452 because the subscriber station 10 next wants to participate in arbitration to send a frame 450 on the bus 40 itself.
    For safety's sake, the receive threshold switching block 152 also switches from the operating mode B_452 RX back to the operating mode B_451 if the transmission block 121 sends something to the bus 40 during the current data phase.
    452. This is illustrated with a downshift state S5 on the arrow between the operating modes B_452 RX, B_451. In the operating mode B_ 452 RX, the transmission block 121 usually does not send anything to the bus 40 until an error is detected, so that the transmission block 121 sends an error frame 47 to the bus 40. The downshift condition S5 represents a safety measure so that. the communication in bus system 1 can be safely restarted from the first operating mode B_451.
    For safety's sake, the receive threshold switching block 152 also switches back from the operating mode B_452_TX to the operating mode B_451 if the transmission signal TxD is constant for a predetermined time t of
    For example, more than 5 ps, as illustrated by a downshift condition S6 on the arrow between the operating modes B_452_TX, B-_ 451. The downshift condition S6 represents a safety measure to make the communication in the bus system 1 robust against fault conditions.
    In addition, the receive threshold switching block 152 is designed to switch from the operating mode B_451 to the operating mode B_452 RX_A if, for example, one of the following three turn-on conditions S1_1, S1_2, S1_3 is present, as illustrated in Figure 9 by the arrow between the operating modes B_451, B 452 RX_A. The operating mode B_452 RX_A can also be referred to as “Auto Fast RX” mode.
    The switch-on condition S1_1 is present when the subscriber station 10 is switched on and must be integrated into a running bus communication.
    The enable condition S1_2 is present when the subscriber station 10 is switched to the protocol exception state.
    The switch-on condition S1_1 is present when a subscriber station 10, 30 has lost synchronization with a sending subscriber station 10, 30.
    In the operating mode B_452 RX_A, the receiving threshold switching block 152 switches between the receive thresholds T_a of the “Slow” operating mode B_451 and the receive threshold T_d of the “Fast RX” operating mode B_452 RX using the receive threshold T_e, as described below.
    In the operating mode B_452_RX_A, the transmitting / receiving device 12 initially operates with the receive threshold T_a of "Slow" operating mode B_451 and the receive threshold T_e. Once the
    -20. reception threshold Tc is undershot, the transmitting / receiving device 12, more precisely its block 152, switches the reception threshold T_a for a predetermined time period t_A (tAuto_Mode) to the reception threshold T_d of the "Fast RX" mode B_452 RX. After the predetermined time period t_A has elapsed, the transmitting / receiving device 12, particularly its block 152, switches the receive threshold T_d back to the receive threshold T_a of the "Slow" operating mode B_451. For example, the time period t_A is set in the configuration mode B_420 so that the transmitting / receiving device 12 operates in the predetermined time period t_A, in which the transmitting / receiving device 12 operates with the receive threshold T_d of the "Fast RX" operating mode B 452 RX, forwards at least one stuff bit to the communication device 11. In this way, the idle state 410 is avoided from being incorrectly recognized during the data phase 452 of a CAN XL frame 450.
    During the data phase 452 of a CAN XL frame 450, the transmitting / receiving device 12 may switch multiple times, as described above. The receive threshold switching block 152 therefore switches back from the operating mode B_452_RX_A to the operating mode B_451 if the receive threshold T_c is not undershot during the predetermined time period t_A, as illustrated by a downshift condition S4_3 on the arrow between the operating modes B_ 452 RX_A, B_451. The downshift occurs when the data phase 452 has ended and therefore no more Data_1 levels are sent on the bus 40. The automatic switch back to the receive threshold T_a of the “Slow” operating mode B_451 ensures that an inactive state 410 after the data phase 452 is reliably detected.
    After the idle state 410 has been recognized, the communication device 11 is integrated into the bus communication and the transceiver 12 switches off the
    -30- “Auto Fast RX” mode or operating mode B_452 RX_A to “Slow” operating mode i.e. operating mode B_451. The downshift condition S4_3 represents a measure to enable the subscriber station 10 to integrate into the bus communication. In the operating mode B_452 RX_A, the subscriber station 10 can use the reception threshold T_c to avoid incorrect recognition of the idle state 410 if the subscriber station 10, for example after switching on, does not yet know in which operating mode B_451, B_452_RX, B_452_TX the other transmitting / receiving devices 22, 32 work in the bus system 1.
    This prevents the subscriber station 10, which switches its transmitting / receiving device 12 to the “Slow mode” or operating mode B_451 for the integration, from ending the integration too early because the subscriber station 10 uses the “Data-0” bits of a cannot reliably recognize current CAN XL frame 450. If the subscriber station 10 terminates the integration too early, the subscriber station 10 may disrupt the communication.
    In addition, it prevents the subscriber station 10, which switches its transceiver 12 to the “Fast-Mode” or the operating mode B_452_RX for integration, from ending the integration too late or not at all, if the subscriber station 10 does not end all recessive bits 401 of a dormant CAN. bus 40. If the participant station 10 never ends the integration, then the participant station 10 cannot participate in the communication.
    FIG. 10 shows a state diagram illustrating an embodiment of the operating mode setting device 15 and of the receive block 122 or of the transmitting / receiving device 12 according to a second embodiment. The operating mode setting device 15 and the receive block 122 or the transmit / receive device 12 are designed in accordance with the present exemplary embodiment,
    With the exception of the differences described below, such as the operating mode setting device 15 and the receive block 122 or the transmit / receive device 12 according to the previous embodiment.
    Unlike the previous embodiment, the operating mode setting device 15 replaces the “Slow” mode or the operating mode B_451 with the “Auto Fast RX” mode or the operating mode B_452 A, as illustrated in Figs. 10. The subscriber station 10 thus uses the "Auto Fast RX" mode or the operating mode B_452 A not only for integration, as previously described with reference to Figure 9, but also during normal communication. In this case, a second predetermined time t_A_10 ((tAuto_Off) is specified in the operation mode setting device 15, in particular its reception threshold switching block 152, in which automatic switching of the reception thresholds T_d, T_c is disabled. The automatic switching is then disabled, for example for the time t_A_10 (tAuto_Off) after the communication controller 11, more specifically its protocol controller, has changed the operating mode or after the TxD input of the transmitter / receiver device 12 of the communication controller 11 is set to "0". In this way, a subscriber station 10, 30, which, for example, cannot recognize the length of a received CAN XL frame 450 due to an error in the header checksum (header CRC error), can use the reintegration pattern at the end of a CAN XL frame 450 without previously misrecognizing the idle state 410. This allows the subscriber stations 10, 30 to recover after errors can be reintegrated without using the classic CAN error frames (error flags) 47. This is very advantageous as it does not affect the ongoing communication
    -32- disrupts and interrupts. This allows the net data rates in bus system 1 to be further increased. All previously described configurations of devices 15, 35, subscriber stations 10, 20, 30, bus system 1 and the method performed therein can be used individually or in all possible combinations. In particular, all features of the exemplary embodiments described above and / or their modifications can be combined as desired. In addition to or as an alternative, the following modifications in particular are conceivable. Also, if the invention is described above with reference to the CAN bus system example, 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 generated for the different communication phases are different. shall. In particular, the invention can be used in the development of other serial communication networks, such as Ethernet and / or 100 Base-T1 Ethernet, field bus systems, etc.
    In particular, the bus system 1 according to the exemplary embodiments can be a communication network on which data can be serially transmitted at two different bit rates. It is advantageous, but not mandatory, that in the bus system 1 an exclusive, collision-free access from a subscriber station 10, 20, 30 to a common channel is guaranteed at least for certain periods of time. The number and arrangement of the subscriber stations 10, 20, 30 in the bus system 1 of the exemplary embodiments is arbitrary. In particular, the subscriber station 20 in the bus system 1 can be omitted. It is possible that one or more of the subscriber stations 10 or 30 are present in the bus system 1. It is conceivable that all subscriber stations in the
    233. bus system 1 are configured identically, i.e. only subscriber station 10 or only subscriber station 30 is present. The number of reception thresholds T_c added to the reception threshold T_d or T_a can also be increased even further than described above. As a result, the plausibility check of the detection of the current operating mode of the ongoing communication can be further improved. However, the effort involved in evaluating the thresholds increases with the number of associated receive thresholds T c.
    All previously described operating mode recognition variants can be time filtered to increase robustness with respect to electromagnetic compatibility (EMC) and against electrostatic charge (ESD), pulses and other disturbances.
    权利要求:
    Claims (14)
    [1]
    -34- Claims 1) Device (12; 32) for a serial bus system (1), having a reception block (122) for receiving a signal (VDIFF) from a bus (40) of the bus system (1), the signal (VDIFF) is based on a transmission signal (TxD), with which a message (45) is exchanged between subscriber stations (10, 20, 30) of the bus system (1), and wherein the receive block (122) is arranged to transmit the signal ( VDIFF) in a first communication phase (451; 453, 451), in which a recessive bus state (401) in the signal (VDIFF) can be overwritten by receiving a dominant bus state (402), with a first receive threshold (T_a), and the signal (VDIFF) in a second communication phase (452), in which bus states other than the recessive and dominant bus states (401, 402) are present in the signal (VDIFF) with a second receive threshold (T_d) to receive, an evaluation block (151) to evaluate the signal (VDIFF) from the bus (40) of the bus system (1) with a switching reception threshold (T_c), which is different from the first reception threshold (T_a) and the second reception threshold (T_d), and a reception threshold switching block (152) for temporarily switching the reception threshold of the reception block (122) from the first reception threshold ( T_a) to the second receive threshold (T_d), when the evaluation block (151) recognizes with the switching receive threshold (T_c) in the signal (VDIFF) the bus level (VDIFF_1) for Data_1 of the transmission signal (TxD).
    [2]
    The device (12; 32) of claim 1, wherein the receive threshold switching block (152) is designed to temporarily switch the receive threshold of the receive block (122) from the first receive threshold (T_a) to the second receive threshold (T_d) in the receive block (122) around a
    -35- switch operating mode (B_452_RX_A) which differs from three other operating modes of the device (12; 32), the three other operating modes of the device (12; 32) including a first operating mode (B_451) for transmitting and / or receiving the signal (VDIFF) in the first communication phase (451; 453, 451), a second operating mode (B_452_RX) only for receiving the signal (VDIFF) in the second communication phase (452), and a third operating mode (B_452_TX) for sending and receiving the signal (VDIFF) in the second communication phase (452).
    [3]
    The device (12; 32) of claim 1, wherein the receive threshold switching block (152) is designed to temporarily switch the receive threshold of the receive block (122) from the first receive threshold (T_a) to the second receive threshold (T_d) in a first operating mode (B_451) in which the reception of the signal (VDIFF) in the first communication phase (451; 453, 451) is performed.
    [4]
    Device (12; 32) according to any one of the preceding claims, wherein the evaluation block (152) is a comparator having an input for connection to two bus lines (41, 42) of the bus (40), and the output of which is connected with the receive threshold switch block (152).
    [5]
    5) Apparatus (12; 32) according to any one of the preceding conelusions, wherein the evaluation block (152) is designed to check whether the handover receive threshold (T_c) through a bus level for
    236 - Data_1 of the transmission signal (TxD) in the signal (VDIFF) is undershot.
    [6]
    The device (12; 32) according to claim 5, wherein the switch reception threshold (T_c) is a reception threshold with negative numerical value.
    [7]
    The device (12; 16; 32) according to any one of the preceding claims, wherein the bus states (401, 402) of the signals received in the first communication phase (451; 453, 451) from the bus (40) are generated with a different Physical Layer then the bus states (VDIFF_D0, VDIFF_D1) of the signal received in the second communication phase (452).
    [8]
    An apparatus (12; 16; 32) according to any one of the preceding claims, wherein the bus states (401, 402) of the signal received from the bus (40) in the first communication phase (451; 453, 451) have a longer bit time (t_bt1) then have the bus states (VDIEF_ DO, VDIFF DI) of the signal received in the second communication phase (452).
    [9]
    Device (12; 32) according to one of the preceding claims, negotiated in the first communication phase (451; 453, 451), which of the subscriber stations (10, 20, 30) of the bus system (1) in the next second communication phase (452) is granted at least temporarily exclusive, collision-free access to the bus (40).
    [10]
    Device (12; 32) according to any one of the preceding claims, including a sending block (121) for sending messages (45) on a bus (40) of the bus system (1), the sending block (121) at the transmission of the different communication phases (451 to 453) of a message (45; 46) is equipped to switch between a transmission mode of operation (B_451) for the
    -37- switch a first communication phase (451; 453, 451) and an operating mode (B_451_TX) for the second communication phase (452).
    [11]
    11) Subscriber station (10; 30) for a serial bus system (1), with a communication controller (11; 31) for controlling the communication between the subscriber station (10; 30) and at least one other subscriber station (10; 20) 30) of the bus system (1) and a device (12; 32) according to any one of the preceding claims.
    [12]
    Subscriber station (10; 30) according to claim 11, wherein the communication control device (11; 31) is designed to switch the device (12; 32) to an operating mode (B_451) for sending and / or receiving the signal ( VDIFF) in the first communication phase (451; 453, 451) when the communication control device (11; 31) recognizes an idle state (410) of the bus.
    [13]
    13) Bus system (1), with a bus (40), and at least two subscriber stations (10; 20; 30), which are connected via the bus (40) in such a way that they can communicate with each other in series and of which at least one subscriber station (10; 30) is a subscriber station (10; 30) according to claim 11 or 12.
    [14]
    14) Method of communication in a serial bus system (1), the method being performed with a device (12; 32) having a receive block (122) for receiving a signal (VDIFF) from a bus (40) of the bus system (1), an evaluation block (151) and a receive threshold switching block (152), and wherein the device (12; 32) performs the steps of,
    -38- receive, with the receive block (122) of a signal
    (VDIFF) of a bus (40) of the bus system (1) based on a transmission signal (TxD) with which a message (45) is exchanged between subscriber stations (10, 20, 30) of the bus system (1) the receiving block ( 122) is designed to transmit the signal (VDIFF) in a first communication phase (451; 453, 451), in which in the signal (VDIFF) a recessive bus state (401) can be overwritten by a dominant bus state (402), with a first receive threshold (T_a), and the signal (VDIFF) in a second communication phase (452), in which bus states other than the recessive and dominant bus states (401, 402) are present in the signal (VDIFF), with a second receive threshold (T_d ) receive,
    evaluate, with the evaluation block (151), the signal
    (VDIFF) of the bus (40) of the bus system (1) with a handover receive threshold (T_c) that differs from the first receive threshold (T_a) and the second receive threshold (T_d), and momentary handover, with the receive threshold
    switching block (152), the reception threshold of the reception block (122) from the first reception threshold (T_a) to the second reception threshold (T_d), if the evaluation block (151) with the switching reception threshold (T_c) in the signal (VDIFF) the bus level (VDIFF_1) for Data_1 of the transmission signal (TxD)
    detects.
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    同族专利:
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    DE102019213926A1|2021-03-18|
    NL2026452B1|2021-09-28|
    WO2021047894A1|2021-03-18|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE102016224961A1|2016-12-14|2018-06-14|Robert Bosch Gmbh|Subscriber station for a bus system and method for data transmission in a bus system|
    DE102018202170A1|2017-12-22|2019-06-27|Robert Bosch Gmbh|Subscriber station for a serial bus system and method for sending a message in a serial bus system|
    DE102018202167A1|2017-12-22|2019-06-27|Robert Bosch Gmbh|Subscriber station for a serial bus system and method for sending a message in a serial bus system|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102019213926.4A|DE102019213926A1|2019-09-12|2019-09-12|Device for a subscriber station of a serial bus system and method for communication in a serial bus system|
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