Transmission / reception apparatus and method for selectively waking up subscriber station of serial bus system

Abstract

A transmitting / receiving apparatus and a corresponding method for selectively waking up a subscriber station of a serial bus system. The transmission / reception device has a transmission module for transmitting, as an analog signal, a transmission signal created on the basis of the frame for communication in the bus system to a bus of the bus system; the receiving module is used for receiving an analog signal from a bus of the bus system and generating a digital receiving signal according to the analog signal received from the bus; and a wake-up module for waking up the subscriber station after the subscriber station has been put into sleep to save energy wherein the wake-up module is designed to serially perform at least two different evaluations to determine whether the digital received signal corresponds to a wake-up frame indicating activation of the transmitting module to wake up the subscriber station, and the wake-up module is designed to determine whether the digital reception signal corresponds to the wake-up frame, in which the digital reception signal is decoded in a format different from that in the transmission signal that has been encoded in the predetermined region.

Description

Technical Field

[0001] The invention relates to a transmitting / receiving device for selectively waking up a subscriber station of a serial bus system and a method for selectively waking up a subscriber station of a serial bus system. Background Art

[0002] Bus systems are used in many technical fields for communication between technical devices such as sensors and control devices. In some bus systems, the technical devices are to communicate with one another and should be able to switch between different standards and / or rates for data transmission or communication between user stations of the bus system, if necessary and as required.

[0003] At present, the communication between the devices in the vehicle and / or between the devices of other technical devices is carried out using the classic CAN and / or CAN FD, both of which are standardized in the international standard ISO11898-1:2015. In addition, CAN XL can be used, which is described in detail in CiA610-1 and is currently integrated into ISO11898-1. In such a communication based on the CAN bus, frames are used to generate a transmission signal, which is divided into an arbitration phase and a data phase. In the arbitration phase, it is negotiated between the user stations of the bus system: which user stations of the bus system can exclusively access the bus in the subsequent data phase, and then their data can be sent to the bus. Compared with the arbitration phase, in the data phase, the bits of the transmission signal are generated with a shorter bit time, in other words, with a higher bit rate in the case of CAN FD and CAN XL, and sent to the bus. With the SIC and SIC XL transceiver devices (also called transceivers), bit rates of up to 8 Mbit / s are possible in the data phase in CAN FD and up to 20 Mbit / s in CAN XL. In the arbitration phase, however, the bit rate remains at approximately 500 kbit / s in order to enable arbitration.

[0004] In order to reduce the energy consumption of systems (e.g. vehicles) etc., subscriber stations that are not currently needed on the CAN bus should be put to sleep and woken up again when needed. The wake-up can either be carried out using a predetermined wake-up pattern, which all subscriber stations of the bus recognize and participate in the communication on the bus again due to the wake-up pattern, or the wake-up signal is sent by the management subscriber station and is designed so that at least individual subscriber stations of the bus can be woken up individually or selectively. The wake-up is usually carried out using a CAN send / receive device (transceiver), which generates such a wake-up signal with the help of a classic CAN frame. This is described in the international standard ISO 111898-2:2016.

[0005] Selective waking up can be carried out in a resource-efficient implementation using Classical CAN frames and clock sources available for this purpose which have a high tolerance and are therefore cost-effective.

[0006] However, problems arise when bit rates of more than 8 Mbit / s are to be used in the bus system, for which (one or more) transmit signals based on CAN XL frames are to be used. However, for such bit rates, CAN XL must be operated with SIC XL transceivers and error signaling must be disabled for CAN XL communication. As a result, CANXL automatically loses compatibility with CAN FD and Classical CAN. As a result, only CAN XL communication is still used on the bus. This has the disadvantage that selective wake-up with Classical CAN frames can no longer be used.

[0007] Another problem is that using CAN XL frames for selective wake-up is very expensive compared to classic CAN frames. The reason for this is that CAN XL requires a precise clock and the complexity of the CAN XL protocol is significantly higher. Summary of the invention

[0008] Therefore, the object of the present invention is to provide a transmitting / receiving device for selectively waking up a subscriber station of a serial bus system and a method for selectively waking up a subscriber station of a serial bus system, which solve the above-mentioned problems. In particular, a transmitting / receiving device for selectively waking up a subscriber station of a serial bus system and a method for selectively waking up a subscriber station of a serial bus system should be provided, wherein even when different communication standards and bit rates are used in the arbitration and data phases for all (currently) possible bit rates, individual subscriber stations can be selectively woken up in an easy and cost-effective manner.

[0009] This object is achieved by a transmitting / receiving device for selectively waking up a subscriber station of a serial bus system, having the features of claim 1. The transmitting / receiving device has a transmitting module for transmitting a transmit signal as an analog signal to a bus of the bus system, the transmit signal being created on the basis of frames for communication in the bus system; a receiving module for receiving the analog signal from the bus of the bus system and for generating a digital receive signal based on the analog signal received from the bus; and a wake-up module for waking up the subscriber station after the subscriber station has been put to sleep to save energy, wherein the wake-up module is designed to perform at least two different evaluations in series in order to determine whether the digital receive signal corresponds to a wake-up frame, the wake-up frame indicating that the transmitting module is activated for waking up the subscriber station, and wherein the wake-up module is designed to decode the digital receive signal in a predetermined area in a format different from that in which the predetermined area was encoded in the transmit signal in order to determine whether the digital receive signal corresponds to the wake-up frame.

[0010] The described embodiment of the transmitting / receiving device makes it possible to selectively wake up at least one subscriber station of a serial bus system using an embodiment that can be used independently of a possible bit rate in the bus system.

[0011] The described transmitting / receiving device can therefore use the same frames in the bus system at bit rates below 8 Mbit / s and at bit rates above 8 Mbit / s. Therefore, even at higher bit rates, there is no need to switch the selective wake-up mode.

[0012] Selective waking can be realized in an uncomplicated and therefore cost-effective manner, since the described transmitting / receiving device does not have to be able to decode the short bits of the CAN XL data phase individually.

[0013] The costs of the described transmitting / receiving device (wake-up transceiver) are very advantageously kept low. One reason for this is that the complexity of the method executed by the transmitting / receiving device for wake-up corresponds approximately to the complexity in the case of the classic CAN. Another reason is that a clock source with a high tolerance (i.e. low precision) is sufficient for the transmitting / receiving device.

[0014] Thus, in the data phase, CAN XL can be operated with SIC XL transceivers for high bit rates of up to 20 Mbit / s and error signaling can be disabled in the case of CAN XL. In this case, however, the previously described options for cost-effective selective wake-up are still available.

[0015] Furthermore, the previously described techniques of the transmitting / receiving device (wake-up transceiver) can also be used when using CAN FD communication. It also applies that the previously known method for generating a wake-up signal by means of a Classical CAN frame described in the international standard ISO 111898-2:2016 can be used in the case of CAN FD.

[0016] Overall, therefore, the bus system can be operated very energy-efficiently and therefore cost-effectively due to the high bit rate that can be used in the data phase and the resulting more frequent possibility for selectively putting individual subscriber stations of the bus system to sleep.

[0017] The described subscriber station also enables at least two subscriber stations to be present in the bus system, which send messages to the bus according to different CAN standards. Thus, for example, in addition to the two CAN-XL subscriber stations, at least one further subscriber station can be present in the bus system, which sends messages to the bus according to another / different CAN standard.

[0018] Advantageous further embodiments of the subscriber station are described in the dependent claims.

[0019] The wake-up module can be designed for decoding in different formats to decode the digital received signal in at least a portion of a predetermined area using at least one first bit duration, wherein the first bit duration is a multiple of a second bit duration, wherein the predetermined area has already been encoded with the second bit duration in the transmitted signal.

[0020] Possibly, the wake-up module is designed to perform decoding of pulse width modulation in at least a part of the predetermined area for decoding in different formats.

[0021] According to an embodiment, the predetermined region comprises a preamble and a pulse width modulation region, wherein the preamble is designed to mark the beginning of the pulse width modulation region.

[0022] According to one embodiment, the predetermined area has a field for a data length code, a data field corresponding to the data length code, and a check field for verifying the correctness of at least a part of the predetermined area, wherein the wake-up module is designed to perform decoding in the predetermined area for evaluating the content of the field of the predetermined area.

[0023] The frame can be divided into a first communication phase and a subsequent second communication phase, so that in the first communication phase it is possible to negotiate between the user stations: which user station of the bus system has at least temporarily exclusive and conflict-free access to the bus in a subsequent second communication phase, wherein a predetermined area is arranged in the second communication phase of the frame, in particular in the data field of the frame.

[0024] The wake-up module is designed, for example, to check at least one of the wake-up conditions before decoding the predetermined area in order to determine whether the digital received signal corresponds to a wake-up frame, wherein the wake-up module is designed to switch the receiving module from a first operating mode to a second operating mode different from the first operating mode if at least one wake-up condition exists.

[0025] At least one wake-up condition may be a priority ID that determines with which time priority a frame may be sent onto the bus.

[0026] The at least one wake-up condition may be a single bit arranged in the received frame (460) immediately after the priority ID.

[0027] In one design, the received frame is a CAN XL frame and the single bit is an RRS bit.

[0028] According to one embodiment, the wake-up module has a decoding block for decoding a received signal output by the receiving module based on a frame, wherein an analog signal has been created on the bus of the bus system (1) according to the frame; and an evaluation block for evaluating the result output by the decoding block to determine whether the digital received signal corresponds to a wake-up frame.

[0029] Possibly, the aforementioned sending / receiving device also has a configuration block for storing at least one wake-up condition of the at least two wake-up conditions, wherein the evaluation block is designed to perform its evaluation when accessing the configuration block, and wherein the evaluation block is designed to generate a signal for activating the energy supply to the sending module when the digital received signal corresponds to a wake-up frame.

[0030] The aforementioned sending / receiving device can be part of a user station, which also has a communication control device, which is designed to sample and evaluate the received signal generated by the sending / receiving device according to a predetermined frame, wherein the communication control device is designed to control the communication between the user station of the bus system and at least one other user station and to evaluate the received signal, wherein the bit time in the first communication phase can be different from the bit time in the second communication phase.

[0031] It is conceivable that the communication control device is designed to negotiate with other subscriber stations in a first communication phase which of the subscriber stations of the bus system has at least temporarily exclusive, conflict-free access to the bus in a subsequent second communication phase.

[0032] The aforementioned (first) subscriber station is designed to send a wakeup frame to the bus of the bus system in order to selectively wake up at least one other (second) subscriber station of the bus system after being put into sleep mode.

[0033] The aforementioned subscriber station may be a first subscriber station and at least one second subscriber station of a bus system, the bus system further comprising a bus, wherein the at least one second subscriber station is connected to the first subscriber station via the bus (40) so that the subscriber stations can communicate with one another serially.

[0034] The aforementioned object is also achieved by a method for selectively waking up a subscriber station in a serial bus system according to claim 17. The method is performed with a transmitting / receiving device having a transmitting module, a receiving module and a waking up module, wherein the method comprises the following steps: using the transmitting module to transmit a transmit signal as an analog signal to a bus of the bus system, the transmit signal being created on the basis of frames for communication in the bus system; using the receiving module to receive the analog signal from the bus of the bus system; using the receiving module to generate a digital receive signal from the analog signal received from the bus; using the waking up module to wake up the subscriber station after the subscriber station has been put to sleep to save energy, wherein the waking up module serially performs at least two different evaluations in order to determine whether the digital receive signal corresponds to a wake-up frame, which indicates activation of the transmitting module to wake up the subscriber station, and wherein the waking up module, in order to determine whether the digital receive signal corresponds to the wake-up frame, decodes the digital receive signal in a predetermined area in a format different from that in which the predetermined area was encoded in the transmit signal.

[0035] This method offers the same advantages as mentioned previously with respect to the transmitting / receiving device.

[0036] Other possible implementations of the present invention also include combinations not explicitly mentioned of features or embodiments described above or below with respect to the embodiments. Here, those skilled in the art will also add individual aspects as improvements or supplements to the corresponding basic forms of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be described in more detail below based on embodiments with reference to the accompanying drawings.

[0038] Figure 1 shows a simplified block diagram of a bus system according to a first embodiment;

[0039] Figure 2 The format of a CAN FD frame according to the aforementioned standard ISO 11898-1:2015 is shown for a message that can be sent by a transmitting / receiving device of a user station for a bus system according to the first exemplary embodiment;

[0040] Figure 3 For can be replaced by Figure 2 A CAN FD frame message transmitted by a transmitting / receiving device of a user station of a bus system according to the first embodiment shows the format of a CAN XL frame according to the aforementioned standard CiA610-1;

[0041] Figure 4 A simplified schematic block diagram shows a user station of a bus system according to a first embodiment;

[0042] Figure 5 shows the time course of the bus signals CAN_H and CAN_L in the case of a subscriber station according to the first exemplary embodiment;

[0043] Figure 6 shows the time course of the voltage difference VDIFF of the bus signals CAN_H and CAN_L in the case of a subscriber station according to the first exemplary embodiment;

[0044] Figure 7 Show Figure 4 A more detailed block diagram of a user station is provided to illustrate the structure of its wake-up module;

[0045] Figure 8 An example of a portion of a digital transmission signal is shown, which a management subscriber station as a first subscriber station creates over time based on a wake-up frame determined for waking up a second subscriber station of the bus system;

[0046] Fig. 9 shows a portion of a received signal, a second user station of the bus system receives a signal from a Figure 8 Decoding the received signal from a signal transmitted via a bus;

[0047] Fig.10 A flow chart showing a method that can be performed in a bus system according to a first embodiment;

[0048] Fig.11 shows a wake-up frame according to a second embodiment; and

[0049] Fig.12 A wake-up frame according to a fourth embodiment is shown.

[0050] In the figures, identical or functionally identical elements are provided with the same reference symbols unless otherwise indicated. DETAILED DESCRIPTION

[0051] Figure 1 As an example, a bus system 1 is shown, which is in particular designed essentially for a CAN bus system, a CAN FD bus system, a CAN XL bus system and / or modifications 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.

[0052] exist Figure 1 In the embodiment, the bus system 1 has a large number of user stations 10, 20, 30, 50, which are connected to the bus 40 using a first bus core 41 and a second bus core 42. The bus cores 41 and 42 can also be called CAN_H and CAN_L, and are used for electrical signal transmission after a dominant level is input for signal coupling or a recessive level or other level is generated in the sending state. Messages 45 and 46 can be transmitted serially in the form of signals between the individual user stations 10, 20, 30, 50 via the bus 40. If an error occurs on the bus 40 during communication, such as in Figure 1 As shown by the jagged black block arrow in FIG. 4 , an error frame (ErrorFrame) 47 having an error flag (Error Flag) and an error delimiter (Error Delimiter) may be optionally sent. Figure 1 The user stations 10 , 20 , 30 are, for example, control devices, sensors, display devices, etc. of a motor vehicle or other technical facilities.

[0053] The user station 50 may also be referred to as a manager user station or a manager node or a selectively awakened user station. The user station 50 is further configured to send a wake-up frame 48 via the bus 40 as required for selectively waking up one of the user stations 10, 20, 30. The wake-up frame 48 may also be referred to as a Wake-Up-Frame or WUF for short. The user station 50 may have an encoding module 58 for encoding the wake-up frame 48. Optionally, the user station 50 is further configured to send a sleep frame 49 via the bus 40 as required for selectively putting one of the user stations 10, 20, 30 into sleep.

[0054] like Figure 1 As shown in FIG. 1 , the user station 10 has a communication control device 11, a transmitting / receiving device 12, and a wake-up module 15. The user station 20 has a communication control device 21, a transmitting / receiving device 22, and a wake-up module 25. The user station 30 has a communication control device 31, a transmitting / receiving device 32, and a wake-up module 35. The user station 50 has a communication control device 51, a transmitting / receiving device 52, and a management module 55. The transmitting / receiving devices 12, 22, 32, 52 of the user stations 10, 20, 30, 50 are directly connected to the bus 40, even if this is Figure 1 Not clarified.

[0055] The communication control device 11, 21, 31, 51 is used to control the communication of the corresponding user station 10, 20, 30, 50 with at least one other user station of the user stations 10, 20, 30, 50 connected to the bus 40 via the bus 40. To this end, the communication control device 11, 31 creates and / or reads a first message 45, which is, for example, a CAN FD message 45. The CAN FD message 45 is constructed based on the CAN FD format, which refers to the CAN FD format. Figure 2 Described in more detail.

[0056] The communication control device 11, 31, 51 can also be designed to provide a CAN FD message 45 or a CAN XL message 46 to the associated transceiver device 12, 32, 52 or to receive a CAN FD message 45 or a CAN XL message 46 from the transceiver device 12, 32, 52 as required. The CAN XL message 46 is constructed based on the CAN XL format, which refers to the Figure 3 The communication control device 11 , 31 , 51 thus creates and reads a first message 45 or a second message 46 , wherein the first and second messages 45 , 46 are differentiated by their data transmission standard, ie in this case by CAN FD or CAN XL.

[0057] The communication control device 21 can be implemented as a conventional CAN controller according to ISO11898-1:2015, that is, as a CAN FD-tolerant classic CAN controller or a CAN FD controller. The communication control device 21 creates and reads a first message 45, for example a CAN FD message 45. In the case of a CAN FD message 45, a number of 0 to 64 data bytes can be included, which are also transmitted at a significantly faster data rate than in the case of a classic CAN message. In particular, the communication control device 21 is implemented as a conventional CAN FD controller.

[0058] The transmitting / receiving device 12, 32, 52 can be designed to provide messages 45 in the CAN FD format or messages 46 in the CAN XL format to the associated communication control device 11, 31, 52 as required or to receive messages 45 in the CAN FD format or messages 46 in the CAN XL format from the associated communication control device 11, 31, 52. In addition, a wake-up module 15, 35 is present, which will be described in more detail below.

[0059] The transmitting / receiving device 22 can be implemented as a conventional CAN transceiver or a CAN FD transceiver according to ISO 11898-1:2015. In addition, there is a wake-up module 25 which can be implemented according to the international standard ISO 11898-2:2016, as explained in more detail below.

[0060] The wake-up module 15 , 35 may also be designed to receive and read a wake-up frame implemented according to the international standard ISO 11898-2:2016.

[0061] The formation of messages 46 in the CAN XL format and the subsequent transmission and reception of such messages 46 can be realized by means of the subscriber stations 10 , 30 , 50 .

[0062] Figure 2 4 shows a frame 450 created by one of the user stations 10, 20, 30, 50 for a message 45 with up to 64 data bytes in the CAN FD format FEFF. The CAN FD frame 450 is transmitted by one of the communication control devices 11, 21, 31, 51, namely by encoding in the digital transmission signal TxD ( Figure 4 ) is provided to the associated sending / receiving device 12, 22, 32, 52 for sending to the bus 40.

[0063] The frame 450 is divided into two communication phases, which are called arbitration phase 451 and data phase 452. The frame 450 starts and ends in the arbitration phase 451. The frame 450 starts with an SOF bit and has an arbitration field 453 ((Arbitration field), a control field 454 (Control field), a data field 455 (Data field), a checksum field 456 (CRC field), an acknowledgement field 457 (ACK=Acknowledge) and a frame end field EOF (EOF=End of Frame). The bits in the arbitration phase 451 of the frame 450 have a longer bit time than the bits in the data phase 452, as shown in FIG. Figure 2 As illustrated by example.

[0064] exist Figure 2 The bits shown in bold at the bottom line in FIG. 4 are sent as dominant or "0" in frame 450. Figure 2 The bit shown in bold at the top line in FIG. 4 is sent as a recessive or "1" in frame 450. Figure 2 Such bits shown with bold dashes in FIG. 4 have predetermined fixed values ​​or prescribed values ​​in frame 450 .

[0065] The arbitration field 453 includes an identifier of the frame 450 in the basic ID field and the ID-ext field. The identifier has 29 bits. The SRR bit and the IDE bit are set between the basic ID field and the ID-ext field. The RRS bit is arranged at the end of the arbitration field 453.

[0066] The control field 454 begins with the FDF bit, followed by the res bit. This is followed by the BRS bit and the ESI bit. The control field 454 ends with the DLC field, in which the length of the subsequent data field 455 is encoded. For the frame 450, the res bit must be sent with a logical value of 0, in other words as a (logical) 0, i.e., dominant. However, if the user station 20 receives the res bit with a logical value of 1, in other words as a (logical) 1, i.e., recessive, the receiving user station 20 sees the protocol abnormal event PAE and enters a re-integrated state or operating mode.

[0067] If the DLC field of the control field 453 has a value of 0, the data field 455 does not exist. The data field 455 has a length corresponding to the value encoded in the DLC field. As mentioned previously, this value can be up to 64 bytes.

[0068] The checksum field 456 contains in the field SBC the number of filling bits modulo 8 that have been inserted into the frame 450 according to the bit filling rule, i.e., a bit inverted thereto should be inserted after each of five identical bits. In addition, the checksum field 456 contains in the CRC field a CRC checksum (also referred to as CRC-Checksumme) and ends with the subsequent CRC delimiter CRC-Del.

[0069] The acknowledgement field 457 contains a bit ACK slot in which a subscriber station that is currently only a receiver of the frame 450 and not a transmitter of the frame may or may not acknowledge the correct reception of the frame 450 from the bus 40. The acknowledgement field 457 ends with a bit ACK-Del, which is also called an ACK delimiter.

[0070] A bit sequence marking the end of the frame 450 is set in the end-of-frame field EOF. Therefore, the bit sequence of the end-of-frame field (EOF) is used to characterize the end of the frame 450. The end-of-frame field (EOF) together with the ACK delimiter causes a number of 8 recessive bits to be sent at the end of the frame 450. This is a bit sequence that cannot appear within the frame 450. As a result, the end of the frame 450 can be reliably recognized by the user station 10, 20, 30.

[0071] After the end-of-frame field (EOF), the inter-frame space (IFS) follows in frame 450. Figure 2 In the case of CAN FD, the interframe space (IFS) is designed in accordance with ISO 11898-1:2015. The interframe space (IFS) has at least 3 bits.

[0072] Furthermore, the mentioned fields and bits are known from ISO 11898-1:2015 and are therefore not described in more detail here.

[0073] In the arbitration phase 451, in the case of CAN FD, by means of an identifier (ID) with, for example, bits ID28 to ID18 in an arbitration field 453, it is negotiated bit by bit between the subscriber stations 10, 20, 30 which subscriber station 10, 20, 30 wants to send a message 45, 46 with the highest priority and can therefore exclusively access the bus 40 of the bus system 1 for the next transmission in the subsequent data phase 452. In the arbitration phase 451, the physical layer is used as in the case of CAN and CAN-FD. The physical layer corresponds to the bit transmission layer or layer 1 of the known OSI model (Open Systems Interconnection Model 1).

[0074] An important point during phase 451 is the use of the known CSMA / CR method, which allows user stations 10, 20, 30 to access bus 40 simultaneously without destroying higher priority messages 45, 46. This makes it relatively easy to add further bus user stations 10, 20, 30 to bus system 1, which is very advantageous.

[0075] The CSMA / CR method requires that a so-called recessive state must be present on the bus 40, which can be overwritten by other subscriber stations 10, 20, 30 with a dominant state on the bus 40. In the recessive state, high-ohmic conditions exist at the individual subscriber stations 10, 20, 30, which, combined with the parasitics of the bus circuit, lead to longer time constants. This results in the maximum bit rate of the current CAN FD physical layer being limited to approximately 2 megabits per second in real vehicle use. With the new CAN SIC physical layer, 5 megabits per second and up to 8 megabits per second are also possible.

[0076] In the data phase 452, in addition to part of the control field 454 of the frame 450, the useful data of the CAN FD frame 450 or message 45 from the corresponding data field 455 and the associated checksum field 456 are transmitted. Then there is a switch from the data phase 452 back to the arbitration phase 451.

[0077] Only when the subscriber station 10 as sender has won the arbitration and therefore has exclusive access to the bus 40 of the bus system 1 for sending, the subscriber station 10 as sender of the message 45, 46 starts to send the bits of the data phase 452 to the bus 40. If the subscriber station 20, 30 wants to send a message 45 or 46 to the bus 40, the same applies to the subscriber station 20, 30.

[0078] Figure 3 For message 46, a CAN XL frame 460 is shown as provided by communication control device 11, i.e., encoded in digital transmission signal TxD, to transmitting / receiving device 12 to bus 40. In this case, communication control device 11 creates frame 460 in the present exemplary embodiment as CAN FD-compatible, as also shown in FIG. Figure 3 The same applies analogously to the communication control devices 31 , 51 of the subscriber stations 30 , 50 and the associated transmission / reception devices 32 , 52 .

[0079] according to Figure 3 , the CAN XL frame 460 for CAN communication on the bus 40 is also divided into different communication phases 451, 452, namely the arbitration phase 451 and the data phase 452. The frame 460 includes an arbitration field 463, a control field 464 having an ADS field for switching between the communication phases 451, 452, a data field 465, a checksum field 466, and a frame end field 467 after the start bit (SOF). This is followed by the frame end field EOF, as in the Figure 2 As in the case of frame 450.

[0080] In the arbitration phase 451, arbitration is also performed for the frame 460 by means of the identifier (ID), as previously described with reference to Figure 2 In the data phase 452, in addition to a portion of the control field 464 of the frame 460, the useful data of the CAN-XL frame 460 or message 46 from the data field 465 and the checksum field 466 are also transmitted. Figure 3 In the case of CAN XL, it is the DAS field that is used to switch back from the data phase 452 to the arbitration phase 451 .

[0081] like Figure 3 As shown in FIG. , the user station 10 partially uses the format known from CAN / CAN-FD according to ISO 11898-1:2015, in particular up to (including) the FDF bit, in the arbitration phase 451 as the first communication phase, such as Figure 2 4 and described above. However, starting from the FDF bit, the user station 10 uses the CAN XL format described below in the first communication phase and in the data phase 452 as the second communication phase. In the CAN XL data phase 452, symmetrical "1" and "0" levels are used for transmission on the bus 40 instead of recessive and dominant levels as in the case of CAN FD.

[0082] Generally speaking, two different stuffing rules are applied when generating the frame 460. Until the FDF bit in the arbitration field 453, the CAN FD or Figure 2 The dynamic bit stuffing rule of the frame 450 of FIG. 4 applies, so that after 5 identical bits, a stuffing bit of inverse phase to this can then be inserted. In the data phase 452 until before the FCP field, the fixed stuffing rule applies, so that after a fixed number of bits, a fixed stuffing bit of inverse phase to the previous bit can be inserted. Alternatively, instead of only one stuffing bit, a number of 2 or more bits can be inserted as fixed stuffing bits.

[0083] In the present exemplary embodiment, the res bit known from CAN FD, which is represented by the XLF bit in frame 460, is used to switch from the CAN FD format to the CAN XL format. The frame formats of CAN FD and CAN XL are therefore identical up to the res bit and the XLF bit. The receiver recognizes in which format the frame 460 is sent only at this bit. CAN XL user stations, i.e., here user stations 10, 30, also support CAN FD. If this bit is sent as 1, i.e., recessive, it is an XLF bit and thus identifies the frame 460 as a CAN XL frame. For Figure 2For a CAN FD frame, the communication control device 11 sets this bit to 0, that is, sets it to the dominant res bit.

[0084] In frame 460, the XLF bit is followed by the resXL bit, which is an explicit bit for future use. For frame 460, resXL must be sent as 0, i.e. explicitly. However, if the user station 10 receives the resXL bit as 1, i.e. implicitly, the receiving user station 10 sees, for example, a protocol exception event PAE (also called Protocol ExceptionEvent) and proceeds as in the case of the CAN FD message 46 for res=1. If the resXL bit is not required for synchronization from the implicit XLF bit to the explicit ResXL bit, the resXL bit can be defined in exactly the opposite way, i.e. the resXL bit must be sent as 1, i.e. implicitly. In this case, in the case of an explicit resXL bit, the receiving user station sees the protocol exception event PAE and changes its operating mode to reintegration.

[0085] In frame 460, after the resXL bit there is a sequence ADS (Arbitration Data Switch), in which a predetermined bit sequence is encoded. This bit sequence allows a simple and safe switch from the bit rate of the arbitration phase 451 (arbitration bit rate) to the bit rate of the data phase 452 (data bit rate). Optionally, within the ADH bit, the operating mode of the transmitting / receiving device 12, 32 is switched from the operating mode B_451 (SLOW) of the arbitration phase 451 to one of the two operating modes B_452_TX, B_452_RX of the data phase 452. The two operating modes of the data phase 452 are the operating mode B_452_TX (FAST_TX) for a transmitting node that can send its signal to the bus 40 in the data phase 452 and the operating mode B_452_RX (FAST_RX) for a receiving node that is only a recipient of signals from the bus 40.

[0086] The subsequent fields until the start of the data field 465 are not described in further detail here. The data field 465 may have up to 2048 bytes.

[0087] After the data field 465, in the frame 460 there is a checksum field 466 with a frame checksum FCRC and an FCP field. In this case, FCP=Frame Check Pattern applies. The FCP field consists of 4 bits with, in particular, the bit sequence 1100. The receiving node uses the FCP field to check whether the receiving node is bit-synchronized with the transmit data stream. In addition, the receiving node is synchronized to the falling edge in the FCP field.

[0088] Following the FCP field is the frame termination field 467. The frame termination field 467 consists of two fields, namely a DAS field and an acknowledgement field or ACK field having at least one bit ACK and a bit ACK-Dlm.

[0089] The DAS field contains the sequence DAS (Data Arbitration Switch), in which a predetermined bit sequence is encoded. The bit sequence DAH, AH1, AL1 allows a simple and reliable switch from the data bit rate of the data phase 452 to the arbitration bit rate of the arbitration phase 451. In addition, during the DAS field, the operating mode of the transmitting / receiving device 12, 32 is optionally switched from the operating mode B_452_TX or B_452_RX (FAST) to the operating mode B_451 (SLOW). In the bit DAH, the operating mode of the physical layer, that is, the transmitting / receiving device 12, 32, is switched from FAST_TX or FAST_RX to SLOW. Bit AH1 is followed by bit AL1 (logic 0) and bit AH2 (logic 1). The two bits DAH and AH1 ensure that there is sufficient time for the operating mode switch of the transmitting / receiving device 11 and that all user stations 10, 30 see a recessive level of significantly more than one arbitration bit time before the edge at the beginning of the AL2 bit (logic 0). This ensures reliable synchronization for the user stations of the bus system.

[0090] The sequence of DAS fields is followed by an acknowledgement field (ACK) in the frame end field 467. A bit for acknowledging or not acknowledging correct reception of the frame 460 is set in the acknowledgement field.

[0091] After the frame termination field 467 in the frame 460 is the frame end field (EOF = End of Frame), as in the Figure 2 This is not the case with CAN FD.

[0092] For a user station for which error signaling is not active and which sends a CAN XL frame, the end-of-frame field (EOF) has a different length depending on whether a dominant or recessive bit is seen in the ACK bit. If the sending user station receives the ACK bit as dominant, the end-of-frame field (EOF) has a number of recessive bits of 7. Otherwise, the end-of-frame field (EOF) is only 5 recessive bits long.

[0093] After the End of Frame field (EOF), in frame 450 is the Inter Frame Space (IFS), as previously described with respect to Figure 2 450 as explained in the frame.

[0094] The following applies to CAN XL.

[0095] - Unlike CAN FD, in the case of CAN XL the identifier ID of the frame 460 is called “priority ID”.

[0096] - Unlike CAN FD, CAN XL can send the RRS bit as a (logical) 0 or a (logical) 1. In CAN FD, the RRS bit is always sent as a logical 0.

[0097] In the case of CAN XL, the bit rate in the data phase 452 must be at least 2 times the bit rate in the arbitration phase 451 .

[0098] Figure 4 The basic structure of a subscriber station 10 is shown, which has a communication control device 11, a transmitting / receiving device 12 and a wake-up module 15, which is part of the transmitting / receiving device 12. Figure 4 is constructed in a similar manner as shown in , but according to Figure 1 The wake-up module 35 is arranged separately from the communication control device 31 and the transmitting / receiving device 32. Therefore, the user station 30 will not be described separately.

[0099] according to Figure 4In addition to the communication control device 11, the transmission / reception device 12 and the wake-up module 15, the user station 10 also has a microcontroller 13 and a system ASIC 16 (ASIC=application-specific integrated circuit), to which the communication control device 11 is assigned, and the system ASIC 16 can alternatively be a system basis chip (SBC), on which a plurality of functions required by the electronic components of the user station 10 are combined. In addition to the transmission / reception device 12, an energy supply device 17 is also installed in the system ASIC 16, which supplies the transmission / reception device 12 with electrical energy. The energy supply device 17 usually provides a voltage CAN_Supply of 5V. However, according to requirements, the energy supply device 17 can provide other voltages with other values. Additionally or alternatively, the energy supply device 17 can be designed as a current source.

[0100] Communications control device 11 may optionally have a coding module 18 which is designed like coding module 58 of subscriber station 50 .

[0101] The transmitting / receiving device 12 also has a transmitting module 121 and a receiving module 122. Even if the transmitting / receiving device 12 is always mentioned below, the receiving module 122 can alternatively be arranged in a separate device outside the transmitting module 121. The transmitting module 121 and the receiving module 122 can be constructed as in the case of a conventional transmitting / receiving device 22. The transmitting module 121 can have at least one operational amplifier and / or a transistor in particular. The receiving module 122 can have at least one operational amplifier and / or a transistor in particular.

[0102] The transmitting / receiving device 12 is connected to the bus 40, more precisely to a first bus core 41 for CAN_H and a second bus core 42 for CAN_L of the bus 40. The voltage supply for the energy supply device 17 is carried out via at least one terminal 43 for supplying electrical energy, in particular the supply voltage CAN-Supply, to the first and second bus cores 41, 42. The connection to ground or CAN_GND is realized via a terminal 44. The first and second bus cores 41, 42 are terminated with a terminating resistor 409.

[0103] Even if the connection is Figure 4 Although not shown for the sake of simplicity, first and second bus cores 41 , 42 are also connected in transmitting / receiving device 12 both to transmitting module 121 (also called transmitter) and to receiving module 122 (also called receiver).

[0104] During operation of the bus system 1, the transmission module 121 can convert the transmission signal TxD of the communication control device 11 transmitted via the terminal TXD into corresponding signals CAN_H, CAN_L for CAN or CAN FD and signals CAN_XL_H, CAN_XL_L for bus cores 41, 42 in the case of CAN XL, and transmit these signals to the bus 40 at the terminals for CAN_H and CAN_L. The digital transmission signal TxD is based on Figure 2 CAN FD frame 450 or Figure 3 The CAN XL frame 460, as mentioned before.

[0105] The receiving module 122 receives Figure 5 The signals CAN_H and CAN_L received from the bus 40 shown in FIG. 4 constitute a digital reception signal RxD, and the digital reception signal is forwarded to the communication control device 11, as shown in FIG. Figure 4 As shown in .

[0106] according to Figure 5 In the example of CAN_H, at least in the arbitration phase 451, the signals CAN_H and CAN_L have dominant and recessive bus levels 401, 402, as is known from CAN. A difference signal VDIFF = CAN_H - CAN_L is formed on the bus 40, which is Figure 6 4 is shown for the arbitration phase 451. In order to identify the individual bits of the signal VDIFF with the bit time t_bt1, the receiving module 122 uses a receiving threshold value T_a of, for example, 0.7 V in the arbitration phase 451. In the data phase 452, the bits of the signals CAN_H and CAN_L can be sent faster than in the arbitration phase 451, i.e. with a shorter bit time t_bt2. Therefore, in the data phase 452, in the case of CAN FD and CAN XL, the signals CAN_H and CAN_L differ from the conventional signals CAN_H and CAN_L at least in their faster bit rate. If required, the receiving module 122 uses at least one receiving threshold value in the data phase 452 that is different from that in the arbitration phase 451.

[0107] against Figure 5 The sequence of states 401 and 402 of the signals CAN_H and CAN_L in Figure 6 The course of voltage VDIFF serves only to clarify the function of subscriber station 10. The sequence of data states for bus states 401, 402 can be selected as required.

[0108] In other words, when the sending module 121 switches to the first operating mode B_451 (SLOW), the sending module Figure 5A first data state is generated as bus state 402 with different bus levels for the two bus cores 41 , 42 of the bus line and a second data state is generated as bus state 401 with the same bus level for the two bus cores 41 , 42 of the bus line of bus 40 .

[0109] Furthermore, the transmission module 121 transmits bits with a higher bit rate to the bus 40 in the second operating mode B_452_TX (FAST_TX) for the time course of the signals CAN_H, CAN_L in the case of CAN FD and CAN XL, which includes a data phase 452. Furthermore, the CAN_H and CAN_L signals can be generated in the data phase 452 of CAN XL using a different physical layer than in the case of CAN FD. As a result, the bit rate can be increased even further in the data phase 452 than in the case of CAN FD. At least in the case of CAN XL, if a user station (receiving node) is not the sender of the frame 450, i.e., not a sending node, in the data phase 452, the user station sets a third operating mode B_452_RX (FAST_RX) in its transmitting / receiving device.

[0110] In operating mode B_LB (idle), the communication control device 11 is switched to an idle or standby state. That is, the communication control device waits for the reception of messages 45, 46. In this state, no communication takes place on the bus 40. In other words, in Figure 4 No signal is received or the value logic 1 is applied to the RXD terminal of the communication control device 11, because the recessive level on the bus 40 corresponds to the bit value = 1 or logic 1 in the received signal RxD.

[0111] In the following, according to Figure 7 The operation of the wake-up module 15 is described in contrast to the current communication standards for Classical CAN, CAN FD and CAN XL.

[0112] Figure 7 The basic structure of a wake-up module 15 for a transmitting / receiving device 12 of a subscriber station 10 is shown. Figure 7 In FIG. 1 , only signals and blocks related to the wake-up module 15 are shown, as follows: The wake-up module 15 has a received signal decoding block 151 , a clock block 152 , an evaluation block 153 and a configuration block 154 .

[0113] The received signal decoding block 151 optionally has a timing element 1511 , which is in particular a counter and / or a clock.

[0114] If the subscriber station 10 is optionally used as the sender of the frame 48, the subscriber station 10 has the already mentioned Figure 4The encoding module 18 shown in FIG. The encoding module 18 can be constructed like the encoding module 58 of the user station 50.

[0115] The clock block 152 outputs a clock pulse T1 with a frequency f to the received signal decoding block 151. When the receiving module 122 is to switch its operating mode from the operating mode B_451 (SLOW) of the arbitration phase 451 to the operating mode B_452_RX of the data phase 452, the received signal decoding block 151 outputs a signal SW2 to the receiving module 122. In the operating mode B_452_RX, the receiving module 122 is set to receive the bit duration t_bt2 ( Figure 5 The evaluation block 153 can output the signal SW1 to the energy supply device 17.

[0116] During operation of the bus system 1, the user station 10 can be put into sleep mode by means of a frame 49, as mentioned above. In other words, the user station 10 is put into sleep mode by means of a frame 49. Whether a frame 49 for putting the user into sleep mode has been received can be evaluated by software, which is implemented in particular in an evaluation block 153 or in a block not shown.

[0117] In the sleep mode, the transmission module 121 is deactivated in the case of the transmission / reception device 12. In the sleep mode, the transmission / reception device 12 does not drive the signals CAN_H and CAN_L onto the bus 40.

[0118] In order to recognize when the sleep mode should be exited again, the wake-up module 15 acts as follows.

[0119] The receiving module 122 decodes the digital receiving signal RxD from the signals CAN_H and CAN_L by means of the receiving threshold value, as described above. The receiving module 122 outputs the digital receiving signal RxD to the receiving signal decoding block 151 .

[0120] The received signal decoding block 151 decodes the digital bit stream in the received signal RxD and outputs the result to the evaluation block 153. The received signal decoding block 151 uses the clock pulse T1 received from the clock block 152 for decoding the bit stream.

[0121] The evaluation block 153 is designed to filter and compare the results received from the block 151. In this case, the evaluation block 153 evaluates whether the CAN frames 45, 46, 47, 48, 49 received from the bus 40 correspond to the previously specified format for the wake-up frame 48. To this end, the evaluation block 153 uses at least one of the wake-up conditions 1541, 1542, 1543 stored in the configuration block 154. For example, the wake-up conditions 1541, 1542, 1543 may include at least one of the following conditions / parameters, namely the identifier ID (priority ID) of the wake-up frame 48, the value of the RRS bit, the combination of the identifier ID (priority ID) of the wake-up frame 48 and the value of the RRS bit. Of course, other or additional conditions / parameters 1541, 1542, 1543 may be used.

[0122] For evaluation by block 153, block 151 decodes the CAN XL frame 460 in the incoming receive signal RxD up to bit resXL ( Figure 3 ). Alternatively, the block 151 decodes the CAN XL frame 460 in the incoming receive signal RxD only up to the bit RRS.

[0123] Furthermore, the evaluation block 153 evaluates the incoming CAN XL frame 460 or the corresponding receive signal RxD up to the bit resXL ( Figure 3 ), the bit resXL previously referenced Figure 3 Alternatively, the evaluation block 153 performs the evaluation until the bit RRS ( Figure 3 ).

[0124] Until the bit resXL, ie before the start of the data phase 452 and thus before the start of the data field 465, the decoding block 151 and / or the evaluation block 153 recognizes whether it is a wake-up frame 48 in principle. The recognition is made according to one of the following conditions, namely

[0125] a) Depending on the value of the bit RRS, the value is either logic 0 or logic 1

[0126] b). According to the value of priority ID.

[0127] According to a first modification of the evaluation block 153 , the evaluation block 153 is designed to evaluate a combination of the aforementioned conditions a). and b). in order to detect whether a wake-up frame 48 is involved.

[0128] In order to detect whether a CAN frame 45 , 46 , 47 , 48 , 49 received from the bus 40 corresponds to a previously defined format of a wakeup frame 48 determined for the subscriber station 10 , the evaluation module 15 proceeds as follows.

[0129] Figure 8The transmitter, for example the user station 50, in particular the encoding module 58 thereof, is explained Figure 3 The digital transmission signal TxD of frame 48 of the CAN-XL frame 460 is encoded. The serially transmitted transmission signal TxD has logic values ​​0 and 1. Figure 8 4 , only some parts at the beginning of the frame 48 at the start bit SOF and at the transition between the arbitration phase 451 and the data phase 452 of the transmit signal TxD are shown in more detail. In the data phase 452, fixed filling bits FS_Bt are inserted between the bits SEC and DLC10. The sender switches after the bit ADH in order to generate bits with a bit duration t_bt2 of the data phase 452. In addition, the sender can switch the operating mode of its transmit / receive device, in particular its transmit module, from the operating mode B_451 (SLOW) of the arbitration phase 451 to the operating mode B_452_TX of the data phase 452 after the bit ADH in order to drive the bits with a bit duration t_bt2 in the data phase 452 to the bus 40 accordingly.

[0130] according to Fig. 9 , receiving based on Figure 8 The receiver of the signal transmitted via the bus 40 interprets or decodes the content of the received signal RxD after the resXL bit and thus in a different way than is usual for the CAN-XL frame 460 in the data phase 452. The receiver thus generates a signal RxD such as Fig. 9 The receiving party is, for example, a user station 10.

[0131] exist Fig. 9 In the example of , the receiver is designed to perform the interpretation or decoding of the PWM symbols starting from bit ADH. Here, PWM stands for pulse width modulation. The three PWM symbols PWM1_1, PWM2_0, PWM3_1 are Fig. 9 . That is, the first and third PWM symbols PWM1_1, PWM3_1 shown have a logic value of 1. The second PWM symbol PWM2_0 shown has a logic value of 0. The length of the PWM symbols PWM1_1, PWM2_0 corresponds to the bit duration t_bt3. The length of the PWM symbol PWM3_1 corresponds to the bit duration t_bt4. Each of the bit durations t_bt3, t_bt4 is a multiple of the bit duration t_bt2 of the data bit.

[0132] To produce Figure 8 The sender, for example, is a user station 50.

[0133] To this end, the sender of the frame 48 encodes a relatively long PWM symbol with a plurality of short bits of the data phase 452 in the transmission signal TxD. The sender can select how many data bits should be used for each PWM symbol (bit duration t_bt2). In other words, the number of data bits used for each PWM symbol can be selected. In this case, however, it is more advantageous if the PWM symbol consists of fewer data bits so that the length of the wake-up frame 48 (WUF) to be sent is as short as possible. Independently of this, the length of the PWM symbol can vary within the wake-up frame 48, e.g. Fig. 9 The size of the PWM symbol can be determined in this way so that the fixed filling bits FS_Bt in the data phase 452 do not interfere with the decoding of the PWM symbol.

[0134] The transmitter basically considers that the PWM symbol starts and ends with a predetermined edge. The predetermined edge can be a falling edge or a rising edge. Furthermore, if, for example, it is applicable that the PWM symbol has a longer 0 phase that is more than 50% longer than the 1 phase, the PWM symbol corresponds to a bit with a logical value of 0 and, for example, corresponds to one of the symbol lengths / bit durations t_bt3, t_bt4. Conversely, if it is applicable that the PWM symbol has a longer 1 phase that is more than 50% longer than the 0 phase, the PWM symbol corresponds to a bit with a logical value of 1 and, for example, corresponds to one of the symbol lengths / bit durations t_bt3, t_bt4.

[0135] If the sender encodes a PWM symbol using, for example, four data bits, where two falling edges delimit a PWM symbol, the PWM symbol starts with a 0 phase and ends with a 1 phase, so that a bit with a value of "0" corresponds to the PWM symbol: "0001", and a bit with a value of "1" corresponds to the PWM symbol: "0111". The sender knows at which positions in the frame 450 to insert the fixed stuffing bits and is designed to take this into account when encoding the PWM. As previously described, the fixed stuffing bits are always inverted with respect to the previous bit.

[0136] Thus, due to the padding bits, the four data bits encoded by the transmitter as a PWM symbol in the transmit signal TxD can have a total of five bits. If the length ratio between the 0 phase and the 1 phase is shifted by no more than the 50% limit and no additional edges are inserted, the receiver can correctly decode the PWM symbol generated by the transmitter.

[0137] For the case where additional edges will be generated by the fill bits in the four data bits encoded by the transmitter as a PWM symbol, the transmitter acts as follows. That is, the transmitter is designed to insert additional fill bits under the precondition that the length ratio shift between the 0 phase and the 1 phase does not exceed the 50% limit. The fill bits shift the fill bit edges so that the fill bit edges coincide with the PWM symbol edges.

[0138] For example, the sender encodes a PWM symbol, which starts from the bit sequence "0111" in the transmission signal TxD, and is encoded into a bit sequence "10111" using the padding bits added at the beginning, wherein the bit sequence "0111" will become the bit sequence "01o11" when the fixed padding bit o (logical value 0) is inserted, and then the bit sequence "10111" is changed into the bit sequence "10I111" using the fixed padding bit I (logical value 1).

[0139] That is to say,

[0140] Instead of "01o11", the sender encodes the bit sequence "0111" through "10111" as "10I111", and

[0141] Instead of "011o1", the sender encodes the bit sequence "0111" through "10011" to "100I11", and

[0142] Instead of "0I001", the sender encodes the bit sequence "0001" through "10001" as "1o0001".

[0143] In the three cases mentioned, since the falling edge is a symbol limit, the previous symbol is extended by "1". This results in the bit sequence "0001" as "00011" and the bit sequence "01111" as "01111", but can be correctly decoded by the receiver.

[0144] If the previous symbol is "0111", then the following applies:

[0145] Instead of "00I01", the sender encodes the bit sequence "0001" through "11001" as "11o001".

[0146] The previous symbol is extended here by two "1s", which results from "0111" to "011111", which can be correctly decoded by the receiver.

[0147] However, if the previous symbol is "0001", the transmitter is designed to re-encode two PWM symbols, that is, also re-encode the previous symbol "0001". That is:

[0148] Instead of "0001" "00I01", re-encode the two symbols as "00001" "1o0001".

[0149] In this way, the PWM symbol is (re)coded so that the stuffing bits become part of phase 0 or phase 1 and so that the edge caused by the stuffing bits coincides with a falling edge at the PWM limit or with a rising edge within the PWM symbol. On the one hand, the stuffing bits may shift the (relative) position of the stuffing bits and may be inverted with respect to the stuffing bits if the stuffing bits are located directly before the stuffing bits.

[0150] This prevents the filling bits set in the symbol from generating one or even two additional edges in the symbol and thus possibly causing erroneous decoding at the receiver.

[0151] Instead of using the falling edge as the delimitation of the PWM symbol, the rising edge may be used as the delimitation of the PWM symbol.

[0152] Of course, other encodings for the PWM symbols are also conceivable, in particular if the transmitter is designed to generate or encode symbols from more than 4 data bits. If the PWM symbol is based on 5 data bits, for example, two PWM symbols fit between two padding bits, and there is one padding bit at the end of every two PWM symbols. Re-encoding with padding bits is then not necessary.

[0153] In contrast, the receiver acts as follows to generate and evaluate Fig. 9 The receiving end is, for example, the user station 10.

[0154] The reception signal decoding block 151 outputs the signal SW2 to the reception module 122 at the beginning of the ADH bit so that the reception module 122 ( Figure 7 ) switches to the operating mode FAST_RX. Therefore, block 151 can correctly receive the Figure 8 The subsequent bus level is formed or has been formed on the bus 40 due to the transmit signal TxD.

[0155] The received signal decoding block 151 also does not decode the subsequent bits in the data phase 452 of the CAN XL wake-up frame 48 according to the CAN XL protocol, which was previously decoded according to Figure 3 Instead, the received signal decoding block 151 uses an alternative decoding, such as Fig. 9 That is, in the case of this example, block 151 is designed to interpret or decode the PWM symbols. Of course, other alternative decodings may be used.

[0156] The receiver of frame 48, more precisely its block 151, will Fig. 9 The PWM symbols PWM1_1, PWM2_0, PWM3_1 in the frame 48_1 are decoded back into bits of the frame 48_1 with a logic value of 0 or 1. The decoding block 151 outputs the decoded data or the frame 48_1 to the evaluation block 153. Thus, the evaluation block 153 can evaluate whether the received frame 48_1 should wake up the subscriber station 10.

[0157] Therefore, the transmitting / receiving device 12, in particular its wake-up module 15, carries out a two-stage method, in which first or at the beginning of a signal / frame it is checked whether the signal received from the bus 40 is based in principle on a wake-up frame 48, and in a second stage of the data phase 452 of the wake-up frame 48 it is checked whether the wake-up frame 48 is intended for the associated subscriber station 10. However, in the second stage, a decoding corresponding to the encoding with which the wake-up frame 48 was encoded is not used, but a different decoding method is used.

[0158] Furthermore, the sender of the frame 48 sets the value of the short bits (high data rate) in the data phase 452 so that a lower bit rate is simulated thereby. As a possibility for alternative bit decoding (lower bit rate) in the data phase 452, the receiver can therefore decode each PWM symbol consisting of a plurality of data bits into a bit with a longer bit duration than the bit duration t_bt2 of one data bit, i.e., into a bit with, for example, the symbol length or bit duration t_bt3 or the symbol length or bit duration t_bt4. This results in a lower bit rate in the data phase 452 at the receiver.

[0159] If the evaluation of the evaluation block 153 shows that the CAN frame 45, 46, 47, 48, 49 received from the bus 40 corresponds to the previously specified format of the wake-up frame 48, the evaluation block 153 outputs a corresponding signal SW1 to the energy supply device 17. The signal SW1 can be, for example, a switching signal designed to switch on the energy supply device 17.

[0160] The sender and the receiver may furthermore be designed to send or recognize the sleep frame 49 using the aforementioned method.

[0161] If the evaluation block 153 evaluates that the CAN frame 45, 46, 47, 48, 49 received from the bus 40 corresponds to the previously specified format of the sleep frame 49, the evaluation block 153 outputs a corresponding signal SW1 to the energy supply device 17. The signal SW1 can be, for example, a switching signal designed to switch off the energy supply device 17.

[0162] A great advantage of the above-mentioned method for selective wake-up is that the start and end of a PWM symbol can be very easily identified at a rising (or falling) edge. For this purpose, a clock pulse with a high tolerance is sufficient.

[0163] Another great advantage of the above-described method for selective awakening is that the length of the PWM symbol has no influence on the decoding of the frame 48_1. Therefore, the wake-up frame 48_1 (WUF) is independent of the bit rate of the data phase 452 or the length t_bt2 of the data bits. Therefore, the sender can send the same frame 48 (WUF) regardless of the bit rate of the data phase 452 or the length t_bt2 of the data bits. For this purpose, the resulting temporal PWM symbol length should remain the same within a tolerance range. In this case, for example, 500 ns to 5000 ns are possible as a tolerance.

[0164] Another great advantage of the above-described method for selective wake-up is that the sender can very well “hide” the fixed stuff bits FS_Bt in the data phase 452 of the CAN XL frame 48 in the PWM symbols, so that the fixed stuff bits FS_Bt do not interfere with the decoding by the receiver.

[0165] If CAN FD communication takes place at the bus 40 instead of CAN XL communication, the wake-up module 25 of the user station 20 can also be put to sleep or woken up, as described in ISO standard 11898-2:2016. For this purpose, the wake-up module 25 is constructed partly identically to the wake-up module 15. However, the configuration of the configuration block 154 is designed differently from that described previously with respect to the wake-up module 15. However, the wake-up module 25 can additionally or alternatively have a design and configuration as described below.

[0166] In the case of a user station 20, the wake-up module 25 acts as follows to check whether the user station 20 should be put to sleep or woken up, as specified in the standard ISO 11898-2:2016. Therefore, the wake-up module 25 can be configured to check the following aspects for wake-up:

[0167] - whether the CAN identifier (also referred to as frame identifier) ​​of the received frame 45 , 46 , 48 , 49 corresponds to the CAN identifier provided for the wake-up frame 48 .

[0168] - whether the data length of the received frame 45 , 46 , 48 , 49 in the DLC code corresponds to the data length specified for the wake-up frame 48 .

[0169] - Whether the data mask of the received frame 45, 46, 48, 49 corresponds to the data mask or a "1" bit in the data field 465 of the wake-up frame 48 in which the subscriber station 20 should wake up.

[0170] If the wake-up module 25 determines that all the conditions mentioned are met for the received frames 45, 46, 48, 49, i.e. frame 48 has been received, the wake-up module 25 performs a wake-up. As a result, the transmission module 121 is activated again. This method is described more precisely in the ISO 11898-2:2016 standard.

[0171] Fig.10 The method is explained in a bus system 1, wherein the transmitting / receiving devices 10, 30, 50, in particular their wake-up modules 15, 35, 55, are designed for selective wake-up, as described above. In addition, it is assumed below that the user station 20 is also designed for sending and receiving CAN XL frames. Alternatively, at least one additional further user station 10 and / or at least one additional CAN FD user station 20 may also be present. The user station 50 is a management user station.

[0172] In this case, the following process can be generated.

[0173] In a first step, all subscriber stations 10 , 20 , 30 , 50 on the bus 40 are awake and communicating.

[0174] In a second step, which occurs at an arbitrary later time, the subscriber station 50 sends a sleep signal to the subscriber stations 20 , 30 using a CAN XL frame (ie, a sleep frame 49 ).

[0175] In the third step, even if the user stations 20, 30 are asleep, the user stations 10, 50 can continue to communicate without the user stations 20, 30 waking up.

[0176] In a fourth step which occurs at an arbitrary later time, the functionality of the subscriber station 30 is again required, so that the subscriber station 30 should be woken up.

[0177] Therefore, the user station 50, in particular its wake-up module 55, performs the following Fig.10 The method shown in .

[0178] according to Fig.10 , the method first reaches step S1 after its start. At step S1, the user station 50 creates a wake-up frame 48 for the user station 30 and sends it via the bus 40. In the case of this example, the wake-up frame 48 is a CAN XL frame, in which the bit RRS=1 and / or the priority ID has the value as expected by the wake-up module 35 according to the configuration for the wake-up frame 48 in the associated configuration block. In addition, there is a data phase 452 as previously referred to Figure 8 The method then proceeds to step S2.

[0179] At step S12, the user station 30 receives the wake-up frame 48, as previously described with reference to Figures 7 to 9Thus, the subscriber station 30 wakes up, since its evaluation module 25, 30 recognizes the wake-up frame 48 from the value of the bit RRS and / or from the value of the priority ID and the encoding in the data phase 452. The method then continues with step S3.

[0180] At step S3, the subscriber station 10, 30, 50 is awake and can communicate. The method then ends.

[0181] Alternatively, the method can return to step S1. According to another alternative, the method continues with a further step in which the subscriber station 50 sends a wakeup frame 48 for waking up other subscriber stations of the bus system 1 or a sleep frame 49 for putting other subscriber stations of the bus system 1 to sleep.

[0182] Fig.11 The structure of a wakeup frame 48A over time t according to a second exemplary embodiment is explained, wherein transceiver devices 10 , 30 , 50 , in particular wakeup modules 15 , 35 , 55 thereof and at least one of encoding modules 18 , 58 , are designed for selective wakeup.

[0183] Frame 48A is constructed as closely as possible from CAN XL frame 460, as previously described with reference to Figure 3 and as described in the first embodiment.

[0184] However, in the present exemplary embodiment, the transmitter, for example the user station 50, in particular its encoding module 58, is designed to insert the preamble 481 and the pulse width modulation area 482 into the frame 48A. The preamble 481 marks the beginning of the pulse width modulation area of ​​the CAN XL frame 48A. Fig.11 In the case of the example shown in , the preamble 481 and the pulse width modulation area 482 are inserted in the data field 465. In particular, the preamble 481 and the pulse width modulation area 482 are inserted at the beginning of the data field 465. However, the preamble 481 and the subsequent pulse width modulation area 482 may be arranged at other positions in the data field 465.

[0185] The preamble 481 may have multiple, but at least two, PWM symbols, as previously described with reference to Figure 8 and Fig. 9 The preamble 481 is constructed accordingly as described for the first embodiment. The preamble 481 consisting of 8 PWM symbols can be, for example, 11110000 or 00001111. Of course, the value of the preamble 481 can be selected to be different from the mentioned values. In particular, the preamble 481 itself does not have to be pulse width modulated, i.e., it does not have to have PWM symbols.

[0186] The value and / or arrangement of the preamble 481 in the frame 48A is selected so that the preamble 481 unambiguously marks the beginning of the data field 465 (Data Field) and cannot have previously appeared randomly.

[0187] Thus, the received signal decoding block 151 is designed to decode the resXL bit ( Figure 3 ) and ignore everything after that until block 151 has identified Fig.11 The received signal decoding block 151 then passes the decoded PWM symbols to the evaluation block 153 so that the block 153 can evaluate whether the frame 48A should wake up the subscriber station 10.

[0188] The preamble 481 has the following advantage: the predetermined field in the CAN XL frame 460 on which the frame 48A is based is omitted or skipped by the decoding block 151 during decoding. Such a predetermined field is, on the one hand, a field that the sender cannot easily determine, such as Figure 3 The SBC field, checksum field PCRC, etc. shown in FIG. On the other hand, such a predetermined field is also Figure 3 The sender of the CAN XL frame 460 can only freely determine the fields such as the DLC field, the VCID field, the SDT field, and the AF field in a limited manner.

[0189] In the third exemplary embodiment of bus system 1, transmitting / receiving device 12 is designed as follows. Fig.11 The transmission / reception device 12, in particular the reception signal decoding block 151, is designed to start the timing element from the resXL bit, for example Figure 7 The timing element 1511 of the receiving signal is then used. Then, the receiving signal decoding block 151 decodes the data stream of the receiving signal RxD with the aid of the PWM symbol only after the timing element 1511 has expired.

[0190] Fig.12 The structure of a wakeup frame 48B over time t according to a fourth exemplary embodiment is explained, wherein transceiver devices 10 , 30 , 50 , in particular wakeup modules 15 , 35 , 55 thereof and optional encoding module 18 are designed for selective wakeup.

[0191] Frame 48B is constructed as closely as possible from CAN XL frame 460, as previously described with reference to Figure 3 However, for a bit stream that may be encoded alternatively, there is a frame format of its own in the data field 465 of frame 48B.

[0192] exist Fig.12 In the example case, the frame format in the data field 465 of frame 48B is constructed as follows.

[0193] The first X bits, for example the first 4 bits, etc., encode the DLC 483 (Data Length Code), so that the data length can be M bytes, that is, 0 to 15 bytes in the example mentioned with X=4. M and X are natural numbers including 0. This is followed by a data field 484, in which 0 to 15 bytes corresponding to the value in the DLC 483 are arranged. This is followed by a check field 485.

[0194] For example, the checksum CRC may be included in the check field 485. Alternatively, the check field 485 includes one or more parity check bits. The check field 485 is used to check whether the received RXD data stream is consistent. The check may be performed by the received signal decoding block 151 or the evaluation block 153.

[0195] According to a modification of the fourth embodiment, frame 48B comprises only fields 483 , 484 , 485 .

[0196] The use of the above-described method to identify the wakeup frame 48 has the following advantages: It is possible to selectively wake up individual subscriber stations 10, 20, 30. The selective awakening that is possible thereby avoids unnecessary awakening and reset to sleep and the resulting data traffic on the bus 40. As a result, not only can the energy consumption of the bus system 1 be minimized, but the net data rate that can be transmitted on the bus 40 can also be increased.

[0197] All previously described embodiments of the subscriber stations 10, 20, 30, the bus system 1 and the methods executed therein can be used individually or in all possible combinations. In particular, all features of the previously described embodiments and / or modifications thereof can be combined as desired. Additionally or alternatively, in particular the following modifications are conceivable.

[0198] Even though the invention has previously been described using a CAN bus system as an example, the invention can be used in any communication network and / or communication method in which two different communication phases are used, in which different bus states are generated for different communication phases.

[0199] In particular, the bus system 1 according to the exemplary embodiment can be a communication network in which data can be transmitted serially at two different bit rates. It is advantageous, but not a mandatory prerequisite, that in the case of the bus system 1, exclusive, conflict-free access to a common channel for a user station 10, 20, 30 is guaranteed at least for a certain period of time.

[0200] The number and arrangement of the user stations 10, 20, 30, 50 in the bus system 1 of the exemplary embodiment are arbitrary. In particular, the user station 20 in the bus system 1 can be omitted. It is possible that one or more of the user stations 10 or 30 are present in the bus system 1. It is conceivable that all the user stations in the bus system 1 are designed identically, that is, only the user station 10 or only the user station 30 is present.

Claims

1. A transmitting / receiving device (12; 32; 52) for selectively waking up a user station (10; 30) of a serial bus system (1), comprising: a transmission module (121) for transmitting a transmission signal (TxD) as an analog signal (VDIFF) to a bus (40) of the bus system (1), the transmission signal being created based on a frame (450; 460) for communication in the bus system (1), a receiving module (122) for receiving the analog signal (VDIFF) from a bus (40) of the bus system (1), and for generating a digital receiving signal (RxD) according to the analog signal (VDIFF) received from the bus (40), and a wake-up module (15; 35; 55) for waking up the user station (10; 30) after the user station (10; 30) has been put to sleep to save energy, wherein the wake-up module (15; 35; 55) is designed to perform at least two different evaluations in series in order to determine whether the digital receive signal (RxD) corresponds to a wake-up frame (48; 48A; 48B) indicating activation of the transmit module (121) in order to wake up the user station (10; 30), and The wake-up module (15; 35; 55) is designed to decode the digital received signal (RxD) in a predetermined area (481, 482; 483, 484, 485) in a format different from that in which the predetermined area (481, 482; 483, 484, 485) has been encoded in the transmitted signal (TxD) in order to determine whether the digital received signal (RxD) corresponds to a wake-up frame (48; 48A; 48B).

2. A transmitting / receiving device (12; 32; 52) according to claim 1, wherein the wake-up module (15; 35; 55) is designed for decoding in different formats to decode the digital received signal (RxD) in at least a part of the predetermined area (481, 482) using at least one first bit duration (t_bt3; t_bt4), wherein the first bit duration (t_bt3; t_bt4) is a multiple of a second bit duration (t_bt2), wherein the predetermined area (481, 482) is encoded with the second bit duration in the transmitted signal (481, 482).

3. The transmitting / receiving device (12; 32; 52) according to claim 1 or 2, wherein the wake-up module (15; 35; 55) is designed to perform pulse width modulation decoding in at least a part of the predetermined area (481, 482) for decoding in different formats.

4. The transmitting / receiving device (12; 32; 52) according to any one of the preceding claims, wherein the predetermined area (481, 482) has a preamble (481) and a pulse width modulation area (482), and The preamble (481) is designed to mark the beginning of the pulse width modulation region (482).

5. The transmitting / receiving device (12; 32; 52) according to claim 1, wherein the predetermined area (483, 484, 485) has a field (483) for a data length code, a data field (484) corresponding to the data length code, and a check field (485) for checking the correctness of at least a part of the predetermined area (483, 484, 485), and The wake-up module (15; 35; 55) is designed to perform decoding in the predetermined area (483, 484, 485) for evaluating the content of the field of the predetermined area (483, 484, 485).

6. The transmitting / receiving device (12; 32; 52) according to any one of the preceding claims, The frame (460) is divided into a first communication phase (451) and a subsequent second communication phase (452), so that in the first communication phase (451) it is possible to negotiate between the user stations (10; 20; 30): which of the user stations (10, 20, 30) of the bus system (1) has exclusive, conflict-free access to the bus (40) at least temporarily in the subsequent second communication phase (452); and The predetermined area (481, 482; 483, 484, 485) is arranged in a second communication phase (452) of the frame (460), in particular in a data field (465) of the frame (460).

7. The transmitting / receiving device (12; 32; 52) according to any one of the preceding claims, wherein the wake-up module (15; 35; 55) is designed to check at least one of the wake-up conditions (1541; 1542; 1543) before decoding the predetermined area (481, 482; 483, 484, 485) in order to determine whether the digital reception signal (RxD) corresponds to the wake-up frame (48; 48A; 48B), and The wake-up module (15; 35; 55) is designed to switch the receiving module (122) from a first operating mode (B_451) to a second operating mode (452_RX) different from the first operating mode (B_451) if the at least one wake-up condition (1541; 1542; 1543) exists.

8. The sending / receiving device (12; 32; 52) according to claim 7, wherein the at least one wake-up condition (1541; 1542; 1543) is a priority ID, which determines with what time priority the frame (460) can be sent to the bus (40).

9. A transmitting / receiving device (12; 32; 52) according to claim 7 or 8, wherein the at least one wake-up condition (1541; 1542; 1543) is a single bit arranged in the received frame (460) immediately after the priority ID.

10. The transmitting / receiving device (12; 32; 52) according to claim 9, wherein the received frame (460) is a CAN XL frame (460) and the single bit is an RRS bit.

11. The transmitting / receiving device (12; 32; 52) according to any one of the preceding claims, wherein the wake-up module (15; 25; 35) comprises: a decoding block (151) for decoding a received signal (RxD) output by the receiving module (122) based on the frame (460) from which the analog signal (VDIFF) has been created on the bus (40) of the bus system (1), and An evaluation block (153) for evaluating the result output by the decoding block (151) to determine whether the digital reception signal (RxD) corresponds to the wake-up frame (48; 48A; 48B).

12. The transmitting / receiving device (12; 32; 52) according to any one of the preceding claims, Furthermore, a configuration block (154) is provided for storing at least one of the at least two wake-up conditions (1541; 1542; 1543), wherein the evaluation block (153) is designed to perform its evaluation when accessing the configuration block (154), and The evaluation block (153) is designed to generate a signal (SW1) for activating the energy supply to the transmission module (121) when the digital reception signal (RxD) corresponds to the wake-up frame (48; 48A; 48B).

13. A user station (10; 20; 30; 50) having A transmitting / receiving device (12; 32; 52) according to any one of the preceding claims, and a communication control device (11; 21; 31) which is designed to sample and evaluate a reception signal (RxD) generated by the transmission / reception device (12; 32; 52) according to a predetermined frame (450; 460), The communication control device (11; 21; 31; 51) is designed to control the communication between a user station (10; 20; 30; 50) of the bus system (1) and at least one other user station (20; 30; 10) and to evaluate the received signal (RxD), wherein the bit time (t_bt1) in a first communication phase (451) can be different from the bit time (t_bt2) in a second communication phase (452).

14. A user station (10; 20; 30) according to claim 13, wherein the communication control device (11; 21; 31) is designed to negotiate with other user stations (10; 20; 30) in the first communication phase (451): which user station (10, 20, 30) of the bus system (1) has at least temporarily exclusive and conflict-free access to the bus (40) in a subsequent second communication phase (452).

15. A user station (50) according to claim 13 or 14, wherein the user station is designed to send a wake-up frame (48; 48A; 48B) to a bus (40) of the bus system (1) in order to selectively wake up at least one other user station (10; 30) of the bus system (1) after being put into hibernation.

16. A bus system (1) having Bus(40), A first user station (50) according to claim 15, and At least one second subscriber station (10; 20; 30) according to claim 13 or 14, which is connected to the first subscriber station (50) via the bus (40), so that the subscriber stations (10; 20; 30; 50) can communicate with each other serially.

17. A method for selectively waking up a user station (10; 30) in a serial bus system (1), wherein the method is performed using a transmitting / receiving device (12; 32; 52), the transmitting / receiving device having a transmitting module (121), a receiving module (122) and a waking up module (15; 25; 35), wherein the method comprises the following steps: The transmitting module (121) transmits a transmission signal (TxD) as an analog signal (VDIFF) to a bus (40) of the bus system (1), wherein the transmission signal (TxD) is created based on a frame (450; 460) for communication in the bus system (1), receiving the analog signal (VDIFF) from the bus (40) of the bus system (1) by means of the receiving module (122), generating a digital receiving signal (RxD) using the receiving module (122) according to the analog signal (VDIFF) received from the bus (40), After the user station (10; 30) has been put to sleep to save energy, waking up the user station (10; 30) using the wake-up module (15; 35; 55), wherein the wake-up module (15; 35; 55) performs at least two different evaluations in series in order to determine whether the digital reception signal (RxD) corresponds to a wake-up frame (48; 48A; 48B) indicating activation of the transmission module (121) in order to wake up the user station (10; 30), and The wake-up module (15; 35; 55) decodes the digital received signal (RxD) in a predetermined area (481, 482; 483, 484, 485) in a format different from that in which the predetermined area (481, 482; 483, 484, 485) has been encoded in the transmitted signal (TxD) in order to determine whether the digital received signal (RxD) corresponds to a wake-up frame (48; 48A; 48B).

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