Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F13/00—Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
  • G06F13/38—Information transfer, e.g. on bus
  • G06F13/42—Bus transfer protocol, e.g. handshake; Synchronisation
  • G06F13/4204—Bus transfer protocol, e.g. handshake; Synchronisation on a parallel bus
  • G06F13/4221—Bus transfer protocol, e.g. handshake; Synchronisation on a parallel bus being an input/output bus, e.g. ISA bus, EISA bus, PCI bus, SCSI bus
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F11/00—Error detection; Error correction; Monitoring
  • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
  • G06F11/0703—Error or fault processing not based on redundancy, i.e. by taking additional measures to deal with the error or fault not making use of redundancy in operation, in hardware, or in data representation
  • G06F11/0706—Error or fault processing not based on redundancy, i.e. by taking additional measures to deal with the error or fault not making use of redundancy in operation, in hardware, or in data representation the processing taking place on a specific hardware platform or in a specific software environment
  • G06F11/0745—Error or fault processing not based on redundancy, i.e. by taking additional measures to deal with the error or fault not making use of redundancy in operation, in hardware, or in data representation the processing taking place on a specific hardware platform or in a specific software environment in an input/output transactions management context
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F11/00—Error detection; Error correction; Monitoring
  • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
  • G06F11/0703—Error or fault processing not based on redundancy, i.e. by taking additional measures to deal with the error or fault not making use of redundancy in operation, in hardware, or in data representation
  • G06F11/0793—Remedial or corrective actions
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L25/00—Baseband systems
  • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
  • H04L25/0264—Arrangements for coupling to transmission lines
  • H04L25/0272—Arrangements for coupling to multiple lines, e.g. for differential transmission
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L2012/40208—Bus networks characterized by the use of a particular bus standard
  • H04L2012/40215—Controller Area Network CAN

Definitions

• the present invention relates to a subscriber station for a bus system and a method for improving the error robustness of a subscriber station of a bus system, in which in particular the error robustness in an information transfer on a bus system even under unfavorable
• the CAN bus system has gained wide acceptance for communication between sensors and ECUs.
• messages are transmitted by means of the CAN protocol, as described in the CAN specification in IS011898.
• techniques have recently been proposed for this, such as CAN-FD, in which messages according to the specification "CAN with Flexible Data Rate,
• the bus line should be terminated on both sides with the line impedance, so that the
• a subscriber station of a CAN bus system consists of a
• Communications processor which is usually integrated in a microcontroller, and a transmitter / receiver, which is also called a transceiver and is usually designed as a separate chip with direct connection to the bus line.
• the reception path usually comprises only a comparator with upstream voltage dividers for bias voltage adaptation, which also
• the transmission path consists of a pull-up and pull-down transistor for the two bus wires of the CAN bus system, which are also called CAN high (C_H) and CAN low (C_L) and for coupling in the dominant levels in the CAN bus system
• Transmission state can be used.
• the recessive levels set when both transistors are not switched, so that the input resistance of the
• Error probabilities in the receiver which may also be called receivers, due to the slower transition from dominant to recessive bus level. Since with CAN-FD an increase of the data rate is achieved especially by shortening the symbol duration in the data part, which is sent after arbitration, this property could restrict the application scenarios for the bus system.
• the distance of the received signal to the decision threshold is very greatly reduced, so that a superimposed noise interference with a much higher probability can lead to a false detection in the CAN transceiver.
• a subscriber station for a bus system and a method which solve the aforementioned problems.
• a subscriber station is to be provided for a bus system and a method in which the transmission quality for information transmission on a bus system, which is in particular a CAN bus system, is improved even under the aforementioned unfavorable conditions of a real bus line.
• the object is achieved by a subscriber station for a bus system with the features of claim 1.
• the subscriber station comprises a transmitting / receiving device for transmitting a signal via the bus system to a further subscriber station and for receiving a signal via the bus
• Bus system in which at least temporarily an exclusive, collision-free access of a subscriber station to a bus line of the bus system
• a modification device for modifying the transmission properties of a transmission path of the transmitting / receiving device and / or the reception properties of a receiving path of the transmitting / receiving device.
• an improvement of the signal on the bus line is achieved by additional measures in the transmitting / receiving device.
• the subscriber station offers a great advantage for the transition from dominant to recessive states, which also applies to CAN and possibly also to FlexRay.
• the subscriber station is especially suitable for the problems at higher switching speeds in the data part of CAN-FD.
• the subscriber station is also suitable for use in higher clocked systems, such as CAN-FD, etc.
• the functionality of the subscriber station with respect to the signal to be transmitted and / or the received signal can also be used in one embodiment in particular as preprocessing in a transceiver or a CAN transceiver or a transceiver chip set or a CAN transceiver.
• the considered functionality is embedded either in the transceiver as a separate electronic component (chip) or in an integrated overall solution in which only one electronic component (chip) is present.
• the subscriber station is suitable for improving the transmission quality in the transmission of information on a CAN bus system even under the aforementioned unfavorable conditions of an actual or real bus topology.
• the subscriber station is also suitable for use in higher clocked systems as a standard CAN bus system and can be in one Implementation in the transmit path and / or receive path of a transceiver, in particular a CAN transceiver chipset realize.
• Subscriber station has this for an additional processing level compared to currently available solutions.
• the modification device may comprise a transmitter output stage for predistorting the signal to be transmitted by the transmitter / receiver device in order to achieve a settling of the bus level on a transmission channel within one cycle of the signal to be transmitted, and / or the modification device may be a receiver modification device for changing the
• the transmitter output stage can be designed to predistort the signal to be transmitted by the transmitting / receiving device in such a way that it transmits the
• the transmitter output stage can be designed for predistorting the data section of the signal to be transmitted by the transmitting / receiving device.
• the transmitter output stage for predistorting the signal to be transmitted by the transmitting / receiving device is designed such that it modifies the voltage level of the signal to be transmitted or the output resistance of the transceiver.
• Transmitter output stage be designed such that they both the
• the state change of the transmission signal may in particular be a change from a dominant to a recessive state of the transmission signal.
• the transmitter output stage comprises a first transistor which can be driven by a first drive signal, a second transistor, which can be driven by a second drive signal, a third transistor, which can be driven by a third drive signal, and a fourth transistor, which is a fourth drive signal is controllable, wherein the first and second Transistor are connected to a terminal for a first bus wire, and wherein the third and fourth transistor are connected to a terminal for a second bus wire.
• the transmitter output stage is designed such that it controls the first to fourth transistor in each case linearly to set a level with a defined internal resistance for the first and second bus load.
• the transmitter output stage is designed such that it controls the first to fourth transistor in each case linearly to set a level with a defined internal resistance for the first and second bus load.
• Transmitter output stage designed to be within each
• Bitschreibs predetermined time courses for the first to fourth drive signal for predistortion of the signal to be transmitted and impedance of a transmission path of the transmitting / receiving device is used.
• the subscriber station described above may be part of a bus system having a bus line, and at least two subscriber stations, which are connected to one another via the bus line (4) such that they can communicate with each other.
• at least one of the at least two subscriber stations is a subscriber station described above.
• the aforementioned object is also achieved by a method for improving the error robustness of a subscriber station of a bus system.
• the method comprises the steps of transmitting, with a transmitting / receiving device of the subscriber station, a signal via the bus system to a further subscriber station or receiving, with the transmitting / receiving device of the subscriber station, a signal via the bus system, wherein at least temporarily an exclusive , collision-free access of a subscriber station to a bus line of the bus system is ensured, and predistorting, with a transmitter output stage of the subscriber station, the signal to be transmitted by the transceiver to a settling of the
• Subscriber station are called.
• FIG. 1 is a simplified block diagram of a bus system according to a first embodiment
• Fig. 2 is an electrical circuit diagram of a transmitting / receiving device of
• Fig. 3 shows a waveform of a transmitted signal, which via the
• Bus system is transmitted according to the first embodiment, and a waveform of an associated control signal TX;
• Fig. 5 is an example of an eye diagram corresponding to the waveform of Fig. 4;
• FIG. 7 is a simplified block diagram of a bus system according to a second embodiment
• Fig. 8 is an electrical circuit diagram of a transmitter / Empfangseinrichtu
• Bus system according to the second embodiment is an electrical circuit diagram of a transmitter output stage of the transmitting / receiving device of the bus system according to the second
• FIG. 11 shows an example of a drive signal for the transmitter output stage according to the second embodiment
• FIG. 13 shows a profile of the output signals of the transmitter output stage according to the second exemplary embodiment for the signals from FIGS. 11 and 12;
• bus system 1 shows a bus system 1, which may be, for example, a CAN bus system, a CAN FD bus system, etc.
• the bus system 1 can be used in a vehicle, in particular a motor vehicle, an aircraft, etc., or in the hospital, etc.
• the bus system 1 has a plurality of subscriber stations 10, 20, 30 which are each connected to a bus line 40 having a first bus core 41 and a second bus wire 42.
• the bus wires 41, 42 can also be called CAN high (C_H) and CAN low (C_L) and serve to couple the dominant levels in the transmission state.
• messages 45, 46, 47 may be in the form of signals between each other Subscriber stations 10, 20, 30 are transmitted.
• the subscriber stations 10, 20, 30 may be, for example, control devices or display devices of a motor vehicle. As shown in FIG. 1, the subscriber stations 10, 30 each have one
• the subscriber station 20 has a communication control device 11 and a transmitting / receiving device 14.
• Subscriber stations 10, 20, 30 are each connected directly to the bus line 40, although this is not shown in Fig. 1.
• the communication control device 11 is for controlling a
• Receiver modification device 12 serves to improve the
• Communication controller 11 may be implemented like a conventional CAN controller.
• the transceiver 13 may be implemented in terms of its transmission functionality, like a conventional CAN transceiver.
• Fig. 2 shows the structure of a transmitting / receiving device 13 of
• the transmitting / receiving device 13 has a transmission path 131 and a reception path 132.
• the transmission path 131 serves to transmit a signal to be transmitted, which is based on one of the messages 45, 46, 47.
• the reception path 132 is used to receive the
• the transmission path 131 and the reception path 132 are each constructed as in a conventional CAN subscriber station.
• the transmitting / receiving device 13 in the receiving path 132 has a first and second input terminal C_H, C_L for connecting the bus wires 41, 42.
• the receiving path 132 two resistors 133, 134, a comparator 135, a processing member 136, and a
• Output terminal 137 arranged.
• the resistor 133 is disposed between a first input of the comparator 135, which input is at positive potential, and the first input terminal C_H.
• the resistor 134 is disposed between a second input of the comparator 135, which input is at negative potential, and the second input terminal C_L.
• a pull-up transistor 138 and pull-down transistor 139 are arranged for the two bus wires 41, 42.
• FIG. 3 shows two waveforms over time that result at a subscriber station 20.
• an example of a measured difference signal C_L-C_H between the bus wires 41, 42 of the bus line 40 is shown.
• the associated control signal TX for the transmission path 131 is shown.
• the switching delay are measured in the
• Difference signal C_L-C_H especially the different time constants recognizable, which sets the desired bus level.
• Fig. 4 is an idealized waveform with exponentially decaying
• Receiver modification device 12 the receiving characteristics of the transmitting / receiving device 13. This is shown in Fig. 5, which will be explained in connection with the method shown in Fig. 6 for improving the error robustness of a subscriber station 10, 30.
• step S2 Reception quality of the transmitting / receiving device 13 is sufficient or not. If the answer is YES in step S2, the process is finished. On the other hand, if the answer is NO in step S2, the flow proceeds to step S3.
• Receiver modifier 12 modified so that it is right in the hatched area of the eye diagram of Fig. 5.
• the thus modified detection time T Di would be slightly below 0.6 on the horizontal axis.
• step S4 the receiver modification device 12 modifies the decision threshold E in FIG. 5 by the receiver modification device 12 slightly raising the decision threshold E up to the modified decision threshold E1 in FIG. 5.
• the modified decision threshold E1 at about 0.7 on the vertical axis. Thereafter, the process returns to the step S2.
• the receiver modification device 12 moves the detection time point T D to the right at the modified detection time point T Di and raises the decision threshold E slightly upwards to the modified decision threshold level El.
• the step S3 also after the Step S4 or performed together with this.
• only the step S3 or the step S4 may be performed.
• Fig. 7 shows a bus system 2 according to a second embodiment.
• the bus system 2 comprises, in addition to at least one subscriber station 10, which is constructed as in the first embodiment, at least one
• Subscriber station 50 and at least one subscriber station 60 are subscriber station 50 and at least one subscriber station 60.
• Subscriber stations 10, 50, 60 are each connected to the bus line 40, as in the first embodiment. Via the bus line 40, the messages 45, 46, 47 in the form of signals between the individual
• Subscriber stations 10, 50, 60 are transmitted, as in the first
• the subscriber stations 50, 60 can be any one of Embodiment.
• the subscriber stations 50, 60 can be any one of Embodiment.
• control devices or display devices of a motor vehicle etc., be.
• the subscriber stations 50, 60 each have one in addition to the communication device 11 and the transmitting / receiving device 13
• the subscriber stations 10, 60 also each have a receiver modification device 12, whereas the subscriber station 50 has no receiver modification device 12.
• the receiver modification device 12 is constructed in the same manner as described in the first embodiment.
• FIG. 8 shows the structure of a transmitting / receiving device 13 of FIG.
• the transmitting / receiving device 13 again has a transmission path 131 and a reception path 132, wherein the Receive path 132 is constructed as in the first embodiment.
• the transmission path 131 in this exemplary embodiment has a first transistor 141, which is driven by a drive signal S H + , a second transistor 142, which is driven by a drive signal S H , a third transistor 143, which is driven by a drive signal S L + , a fourth transistor 144, which is driven by a drive signal S L -.
• the first transistor 141 is connected via a resistor 145 to a terminal A.
• the second transistor 142 is connected to a terminal B via a resistor 146.
• the third transistor 143 is connected via a resistor 147 to the terminal A.
• the fourth transistor 144 is connected via a resistor 148 to the terminal B.
• the first and second transistors 141, 142 are connected to a terminal C_H for the first bus wire 41 of the bus line 40.
• the third and fourth transistors 143, 144 are connected to a terminal C_L for the second bus wire 42 of the bus line 40.
• a logic module 149 connects the transmission path 131 with other components of the transceiver 13 which are not described in greater detail here.
• the transistors 141 to 144 and the resistors 145 to 148 form a transmitter output stage 150, which is shown separately in FIG. 9.
• the terminal A is designated by the voltage VDD and the terminal B by the ground GND.
• the transmitter output stage 150 is for modifying a signal to be transmitted, as shown for example in FIG. 4 with respect to the first embodiment.
• the transmitter output stage 150 is set up in such a way that it predistorted the signal to be transmitted, which can also be called a transmission signal, in order to achieve a faster settling of the desired bus level on the bus line 40.
• the predistortion can be achieved by modifying the voltage level of the respective drive signals S H +, S H -, S L +, S L -.
• Voltage level is adjusted depending on the time after a state change of the respective drive signal S H +, S H -, S L +, S L -.
• the transistors 141 to 144 of Fig. 8 and Fig. 9 are not operated hard in saturation, but linearly driven, so that for both terminals C_L and C_H and thus the bus wires 41, 42 of the bus line 40 has a level defined internal resistance can be adjusted.
• the drive signals S H + and S H - are here for the terminal C_H and thus the bus wire
• the desired levels can be achieved as quickly as possible, which brings advantages in particular for the transition from dominant to recessive states in the data part of CAN-FD.
• the signal to be transmitted by the transmission path 131 is determined at a step S10.
• a subsequent step Sil the signal to be transmitted is predistorted by means of the transmitter output stage 150 by the voltage levels of the respective drive signals S H +, S H -, S L +, S L - are modified. Thereafter, the process is completed.
• FIG. 11 shows an example of a drive signal Xi which has been predistorted for the drive signal X 2 shown in FIG.
• the illustrated form of the overshoots of the voltage level in each case at the state change of the voltage level of the signal is only a specific example.
• the amplitude of the overshoots can also each have the same amount.
• the time characteristic of at least one or all overshoots may also be in the form of a sinusoidal arc, in particular one uniform in all overshoots
• the resulting output signals Yi, Y 2 of the transmitter output stage 150 are shown in FIG. 13.
• the signal drawn with a dashed line in FIG. 13 stands for the output signal Yi, which is due to the drive signal of Fig. 11 results.
• the signal drawn with a solid line in FIG. 13 represents the output signal Y 2 , which results from the drive signal of FIG. 12. It follows that in the output signal Y 2 , which consists of a predistortion with the
• Transmitter output stage 150 results in setting levels earlier than the non-predistorted signal.
• the predistortion can occur in the step Sil by modifying the output resistance of the transceiver 13. Also, the output resistance is adjusted depending on the time after a state change.
• the method according to the present embodiment with its two alternatives is particularly suitable for the transition from dominant to recessive states. This applies to both a CAN bus system and FlexRay.
• the method is also particularly suitable for the problem at higher switching speeds in the data part of CAN-FD.
• the present embodiment is easier to achieve the best possible error robustness than the first embodiment, since the transmission path 131 affects the problem to be solved more relevant.
• a predistortion according to the second embodiment is performed. Therefore, the bus system according to the third embodiment is largely constructed in the same manner as the bus system according to the second embodiment.
• Section of a message 45, 46, 47 which is also called CAN frame, the transmitter characteristics of the transceiver 13 adapted to improve the switching edges.
• FIG. 14 shows, as an example of a CAN frame, the message 45.
• the message 45 has a message header 451, a data section 452, and a
• the data section 452 comprises the data intended for the operation of the respective subscriber station 10, 20, 50, 60.
• the transmitter characteristics of the transceiver 13 are adjusted. With regard to the message header 451 and the message end 453, however, the transmitter characteristics of the transceiver 13 remain unchanged.
• This provides the ability to arbitrate at header 451 and message end 453 and improves the quality of the signal on the bus, especially in the higher clocking portion of the data. At the same time, the possibility of transmitting error bursts can be maintained by appropriate design.
• a predistortion according to the second embodiment is also performed. Therefore, the bus system according to the fourth embodiment is largely constructed in the same manner as the bus system according to the second embodiment.
• the predistortion of the drive signals S H +, S H -, S L +, S L - used in addition to the predistortion of the transmission signal for the dynamic adjustment of the impedance of the transmitter output stage 150.
• Subscriber stations 10, 20, 30, 50, 60 and the method according to the first to fourth embodiments can be used individually or in all possible ways
• Embodiment is described based on a based on the CAN protocol bus system.
• the bus system 1, 2 according to the first to fourth
• an embodiment may also be another type of communication network. It is advantageous, but not necessarily a prerequisite, that in the case of the bus system 1, 2, at least for certain periods of time, an exclusive,
• Bus line 40 or a common channel of the bus line 40 is ensured.
• the bus system 1, 2 is in particular a CAN network or a CAN FD network or a LIN network or a FlexRay network.
• the number and arrangement of the subscriber stations 10, 20, 30, 50, 60 in the bus systems 1, 2 according to the first to fourth embodiments is arbitrary. In particular, only subscriber stations 10 or
• Subscriber stations 50 or subscriber stations 60 in the bus systems 1, 2 of the first to fourth embodiments be present.
• the method can be optimized separately for each specific application, for example CAN-FD, FlexRay, etc.
• the application can also be automatically detected and adapted accordingly.
• the method according to the first exemplary embodiment is faster in CAN-FD than in CAN, so that there is no delay longer than that tolerated by the respective protocol.
• the subscriber stations 10, 30, 50, 60 represent a possibility, especially for CAN-FD, of increasing the reception quality of CAN-FD in the range of customary CAN transmissions when using a significantly higher data rate.
• Embodiment also in a communication control device 61, etc. implement. Additionally or alternatively, it can be integrated into existing products.

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• 2013
  • 2013-07-30 DE DE102013214870.4A patent/DE102013214870A1/de active Pending
• 2014
  • 2014-06-27 US US14/909,348 patent/US10268624B2/en active Active
  • 2014-06-27 WO PCT/EP2014/063653 patent/WO2015014550A1/de active Application Filing
  • 2014-06-27 CN CN201480042968.9A patent/CN105409175B/zh active Active
  • 2014-06-27 KR KR1020167005107A patent/KR20160039651A/ko not_active IP Right Cessation
  • 2014-06-27 EP EP14733634.1A patent/EP3028424A1/de not_active Withdrawn
  • 2014-06-27 JP JP2016530395A patent/JP6291050B2/ja active Active

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