FR3125343A1 - Transmission/reception facility and method for detecting manipulation of the Bus system of a Serial Bus system - Google Patents

Abstract

TITLE: Transmission/reception installation and method for detecting manipulation of the Bus system of a Serial Bus system Transmission/reception installation (12) of a participant station (10) comprising: - a first comparator (151) to exploit the signals (CAN_H, CAN_L) from a Bus (40) with a first reception threshold (T1; T3), - a second comparator (152) to exploit the signals (CAN_H, CAN_L) received from the Bus (40) with a second reception threshold (T2) or a manipulation detection reception threshold (T4), and the second threshold (T2) to determine whether the communication is in a first or a second phase to send a frame on the Bus ( 40), - a driver (1221) for a digital signal (RxD) to a communication control (11), - a logic circuit (1222) for transmitting the output signals (CA1, CA2) of the comparators (151,152) to the driver (1221) for the second reception threshold (T2) in the second comparator, the communication being without its first phase and transmit only the output signal (CA1) of the comparator (151) if the threshold (T4) has been set in this comparator (152). Figure 5

Description

Transmission/reception facility and method for detecting manipulation of the Bus system of a Serial Bus system

FIELD OF THE INVENTION

The present invention relates to a transmission/reception transmission and to a manipulation detection method in a serial bus system in which communication is carried out in particular by differential signals.

STATE OF THE ART

Serial Bus systems are used to transmit messages or data in technical installations. For example, a serial bus system can be used for communication between sensors and control devices in a vehicle or in a production or other technical installation. For data transmission, different standards or data transmission protocols are available. Also known are in particular CAN Bus systems, LVDS Bus systems (low voltage differential signals LVDS), MSC Bus systems (MSC=micro seconds channel) or a 10 base-T1S ethernet.

In the case of a CAN bus system (serial system bus also called Controller Area Network), the information is transmitted by a CAN protocol and/or a CAN FD protocol as defined in the ISO-11898-1:2015 standard. as a specification of the CAN protocol described by CAN FD. In the case of the CAN protocol, for transmission on the Bus, a switch is made between a slow operating mode in a first communication phase (arbitration phase) and a fast operating mode in a second communication phase (data phase ). In the case of the CAN FD Bus system, the data transmission rate is greater than 1 Mbit per second (MDPS) in the second phase of communication. The CAN FD protocol is applied by most manufacturers in a first step with a rate of 500 K bits/s for the arbitration rate and a rate of 2 Mbits/s for the data transmission rate in a vehicle.

To have even higher data rates in the second communication phase, there are following systems for the CAN FD protocol like CAN-SIC and CAN XL. In the CAN-SIC protocol according to the CiA601-4 standard, in the second communication phase a data rate of approximately 5-8 Mbit/s is achieved. In the case of the CAN XL protocol we have a data rate in the second phase of communication which is 10 Mbps; the standard (CiA610-3) is currently set by the CAN organization in “CiA automation”. The CAN XL protocol must assist in addition to the simple transport of data by the CAN bus and also other functions such as safety functions (Safety) and data security (Security) and quality of service (QoS=Quality of Service). These are the elementary properties necessary for a vehicle circulating in autonomous mode.

For communication in a Bus system, the risk is that of manipulation of the network. Such manipulation exists when, in an unauthorized manner, a participating station (node) is removed from the Bus system and/or one is added and/or the length of the lines is modified at points in the network. Such manipulations are at least undesirable and constitute above all, but not exclusively, for a vehicle traveling in autonomous mode, a great safety risk. However, currently, in the standardized standards for CAN Bus system such as ISO11898-2:2016, IEC62228-3, CiA601-4, CiA610-3, there is no network tampering detection function (failure detection). an intrusion).

PURPOSE OF THE INVENTION

The aim of the present invention is to develop a transmission/reception installation and a manipulation detection method in a serial Bus system to solve the problems mentioned above, in particular, to develop a transmission/reception installation and a method of detecting manipulation in a serial Bus system which makes it possible to ensure the security of the Bus system and to increase the communication in the Bus system.

DESCRIPTION AND ADVANTAGES OF THE INVENTION

To this end, the subject of the invention is a transmission/reception installation of a station participating in a serial Bus system comprising a first comparator for exploiting the signals received from a Bus of the Bus system with a first threshold reception, a second comparator to exploit the signals received from the Bus with a second reception threshold or a manipulation detection reception threshold, the reception thresholds used by the comparators being different and the second reception threshold being provided to determine whether the communication on the Bus is in a first or a second phase of communication, for sending a frame on the Bus, a driver for driving a digital reception signal to a communication control facility of the participant station, a logic circuit for transmitting a output signal of the first comparator and an output signal of the second comparator to the pilot if the second reception threshold has been set in the second comparator and that e communication on the Bus is in the first phase of communication, and to transmit only the output signal of the first comparator to the driver if the manipulation detection reception threshold has been set in the second comparator and a connection to transmit the signal output from the second comparator to the communication control facility.

The described send/receive installation is designed to allow reliable and simple detection of manipulations by monitoring Bus signals when the Bus system is operating. This also applies to a communication in which the physical layer switches between two communication phases to communicate with the Bus.

Advantageously, the transmitting/receiving installation uses the existing components to detect the signals of a normal communication in the Bus system. Thus, the transmission/reception installation according to the invention is carried out with reduced means and in a relatively economical manner.

The transmission/reception installation according to the invention makes it possible to meet the conditions of communication according to the requirements of differential signals, in particular by the CAN XL protocol. The conditions for the CAN XL protocol are described in particular in the CiA610-3 standard.

The transmission/reception installation thus guarantees that the certain detection of the connection or removal of a participant station or a modification of a line from the network of the Bus system. This makes it possible to decide whether the addition or deletion of a participant set is authorized or not. Such authorized addition or deletion of a participant station may be made, for example, for the maintenance of components of the Bus system.

In addition, the transmission/reception installation is designed so that the level of the Bus signals can be converted with simultaneous use of two reception thresholds into a digital reception signal. The two reception thresholds used in the different communication phases are different depending on the communication phase. At least one reception threshold will be used to detect manipulations in the Bus system.

The transmission/reception installation according to the invention allows different reception thresholds for operation, for arbitration and the data phase as well as for manipulation detection. This not only allows communication with higher bit rates in the Bus system, but also transmittable bit rates which are not reduced by faults in the communication and/or by manipulation of the Bus system.

The input of the second comparator is less low-pass filtered than the input of the first comparator and the output of the second comparator is less low-pass filtered than the output of the first comparator.

According to a variant, the connection is exclusively provided for transmitting the output signal of the second comparator to the communication control installation.

According to another variant, the connection functions as a connection of the multiplex method for at least two functions of the transmission/reception installation.

The transmission/reception installation comprises a control circuit for switching the reception threshold of the second comparator from the second reception threshold to the manipulation detection reception threshold for a predefined duration in a frame sent in the Bus of the system.

The transmission/reception installation further comprises a protocol controller which seizes a certain predefined moment in the frame so that the control circuit switches the reception threshold of the second comparator.

The transmission/reception installation further comprises an operating mode capture block which captures a predefined instant in the frame at which the control circuit switches the reception threshold of the second comparator.

According to another characteristic, the control circuit switches the reception threshold of the second comparator if the transmission/reception installation is the receiver of the frame.

According to an exemplary embodiment, the transmission/reception installation also has a voltage divider connected to the Bus to supply the signal received from the Bus to the first comparator and to the second comparator, the first and the second comparator being connected to the voltage divider. voltage to simultaneously operate the signals.

According to another characteristic, the transmission/reception installation has a first voltage divider to adjust the first reception threshold or a third reception threshold, the first comparator being connected to the first voltage divider to exploit the signals received from the Bus of the Bus system with the first or the third reception threshold set by the first voltage divider, a second voltage divider for setting the second reception threshold or the manipulation detection reception threshold as the fourth reception threshold, the second comparator being connected to the second voltage divider to exploit the signals received from the Bus with the second or the fourth reception threshold set by the second voltage divider, the first and the second voltage divider being connected to the Bus. The first and the second voltage divider are a resistor circuit to which the first and the second comparators are connected, the first and the second comparator simultaneously exploiting the signals. Additionally or alternatively, at least one voltage divider among the first and the second voltage divider comprises at least one switching unit for switching between the second and the fourth reception threshold for the second comparator, depending on the mode of operation of the transmission/reception installation in which this transmission and reception installation is switched for the first or the second phase of communication for its communication on the Bus. At least one switching unit connects the voltage divider to ground or cuts the connection of the voltage divider to ground.

As an option, there is at least a second comparator.

The transmitting/receiving installation described above may be part of a participant station of a serial Bus system, the participant station further having a communication control installation for controlling communication in the Bus system and generating a transmit digital signal for the transmitter module.

The communication control facility includes a protocol controller to operate the output signal of the second comparator through the branch.

The communication control facility may include a clock to time control the protocol controller, the clock further being arranged to operate the output signal of the second comparator on the tap.

Optionally, the participant station is designed to communicate in a Bus system in that, at least occasionally, it guarantees exclusive, collision-free access of the participant station to the Bus of the Bus system.

The problem is also solved by a manipulation detection method in a Serial Bus system having the characteristics defined above. The method is applied by a transmit/receive facility of a participant station in a Serial Bus system, the transmit/receive facility having a first comparator, a second comparator, a driver and a tap. The method includes the operating steps that the first comparator operates the signals received from the Bus of the Bus system with a reception threshold, a second comparator which operates the received signals with a second reception threshold or a detection reception threshold manipulation, the reception thresholds used by the comparators being different and the second reception threshold being provided or designed to determine whether the communication on the Bus is in its first or its second phase of communication to transmit a frame on the Bus, to transmit with the logic circuit, an output signal from the first comparator and an output signal from the second comparator to the driver if in the second comparator the second reception threshold is set and the communication on the Bus is in its first communication phase and transmit by the logic circuit only the output signal of the first comparator to the driver if in the second comparator is set the manipulation detection reception threshold and control with the pilot, a digital reception signal to the communication control installation of the participant station and send to the connection, the output signal of the second comparator to the control installation Communication.

The process offers the same advantages as those already developed for the transmission/reception installation.

The present invention will be described below in more detail using embodiments shown in the accompanying drawings in which:

simplified block diagram of a Bus system according to a first exemplary embodiment,

diagram explaining the structure of a message which can be sent by a station participating in the Bus system according to the first example embodiment,

example of the ideal timing diagram of the CAN_H, CAN_L signals in the Bus system of the ,

timing diagram of a VDIFF voltage difference that develops on the Bus System Bus as a result of Bus signals from the ,

simplified block diagram of a participant station of the Bus system with a communication control installation and a transmission/reception installation according to the first example embodiment,

diagram of a receiver circuit for a receiver module of the transmission/reception installation according to the first example embodiment,

diagram of a comparator of the receiver module according to the first example embodiment,

simplified block diagram of a participant station of the Bus system with a communication control installation and a transmission/reception installation according to a second embodiment,

example of timing diagram of a digital transmission signal converted according to a first example of embodiment in arbitration phase (SIC mode) into signals CAN_H, CAN_L for a Bus of the Bus system of the ,

timing diagram of the signals CAN_H, CAN_L on change between a recessive Bus state and a dominant Bus state and on return from a recessive Bus state these signals having been transmitted in the arbitration phase (SIC mode) by the transmission signal of the on the Bus,

example of a timing diagram of a digital transmission signal converted according to the second embodiment in data phase, into signals CAN_H, CAN_L for the Bus of the Bus system of the ,

timing diagram of the CAN_H, CAN_L signals which were sent in the data phase with the transmission signal of the on the Bus,

simplified block diagram of a participant station of the Bus system with a communication control installation and a transmission/reception installation according to a third example embodiment,

simplified block diagram of a participant station of the Bus system with a communication control installation and a transmission/reception installation according to a fourth example embodiment,

simplified block diagram of a participant station of the Bus system with a communication control installation and a transmission/reception installation according to a fifth exemplary embodiment and,

simplified block diagram of a station participating in the Bus system with a communication control installation and a transmission/reception installation according to a sixth example embodiment.

In the figures, the same references will be used for the same elements or functionally identical elements.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

There shows a Bus system 1 which is, for example, in segments, in the form of a CAN Bus system, a CAN-FD Bus system or the like. The Bus system can equip a vehicle, in particular a motor vehicle, an airplane or the like, or even be installed in a hospital or other installation of this type.

There shows the Bus system 1 with a set of participating stations 10, 20, 30 which are respectively connected to a Bus 40 or a Bus conductor with a first Bus strand 41 and a second Bus strand 42. The Bus strands 41 , 42 can also be called CAN_H and CAN_L for the signals on the Bus 40. The Bus 40 makes it possible to transmit the messages 45, 46, 47 in the form of signals between the various participating stations 10, 20, 30. The participating stations 10 , 20, 30 can be, for example, control devices or display devices of a vehicle.

According to , the participating stations 10, 30 respectively have a communication control installation 11 and a transmission/reception installation 12. The transmission/reception installation 12 has a transmitter module 121 and a receiver module 122.

The participant station 20 has a communication control installation 21 and a transmission/reception installation 22. The transmission/reception installation 22 has a transmitter module 221 and a receiver module 222.

The transmission/reception installation 12 of the participant stations 10, 30 and the transmission/reception installation 22 of the participant station 20 are respectively connected directly to the Bus 40 although this is not shown in .

The communication control installations 11, 21 serve respectively to control a communication of the respective participant station 10, 20, 30 via the Bus 40 with at least one other participant station among the participant stations 10, 20, 30 connected to the Bus 40.

The communication control facilities 11 establish and read the first messages 45, 47 which are, for example, CAN messages, modified 45, 47. The CAN messages 45, 47, modified are, for example, based on the CAN XL format . Transmit/receive facility 12 is used to transmit and receive messages 45, 47 from bus 40. Transmit module 121 receives a TxD digital transmit signal established by communication control facility 11 for communication. one of the messages 45, 47 and applies this signal to the Bus 40. The reception module 121 receives the signals transmitted by the Bus 40 according to the messages 45 to 47 and generates, from there, a digital reception signal RxD. The receiver module 122 transmits the receive signal RxD to the communication control facility 11.

The communication control installation 21 can be realized as a usual CAN controller according to the ISO 11898-1:2015 standard, i.e. a classic CAN controller accepting CAN-FD or a CAN FD controller. The communication control installation 21 establishes and reads second messages 46, for example, CAN-FR messages 46. The transmission/reception installation 22 is used to transmit and receive the messages 46 from the Bus 40. The module transmit module 221 receives the TxD transmit digital signal established by the communication control facility 21 and puts it into signals in the message 46 on the Bus 40. The receiver module 221 receives the signals transmitted on the Bus 40 according to messages 45 to 47 to generate, from there, a digital reception signal RxD. Otherwise, the transmission/reception installation 22 can be made like a usual CAN transmitter/receiver.

To transmit messages 45, 47 with CAN SIC or CAN XL, the confirmed properties which make CAN and CAN FD robust and user-friendly are taken up, in particular, the frame structure with an identifier and an arbiter according to the known CSMA/CR protocol. The CSMA/CR method or protocol has the consequence that recessive states are required on the Bus 40 which are overwritten by other participating stations 10, 20, 30 with dominant levels or dominant states.

The formation and transmission of messages 45 to different CAN formats, in particular, the CAN FD format or the CAN SIC format or the CAN XL format with the two participating stations 10, 30 as well as the reception of such messages 45 will be described below. later, more precisely.

If an error occurs during communication in the Bus 1 system, at least one of the participating stations 10, 20, 30 can send at least one error frame 48 on the Bus 40 to inform the other participating stations 10 , 20, 30 from default.

There shows a frame 450 which is in particular a CAN XL frame for the message 45, as supplied by the communication control installation 11 to the transmission/reception installation 12 for transmitting on the Bus 40. The control installation 11 establishes frame 450 in this exemplary embodiment as compatible with CAN FD. Alternatively, frame 450 is compatible with CAN SIC.

According to , the frame 450 for the CAN communication on the bus 40 is subdivided into different communication phases 451, 452 namely an arbitration phase 451 (first communication phase) and a data phase 452 (second communication phase). Frame 450 has, after the SOF start bit, an arbitration field 453, a command field 454, a data field 455, a checksum field 456 and an end of frame field 457. In the field end of frame 457, an AL1 bit is sent after the transmission/reception installation 12 has passed from the data phase operating mode 452 to the arbitration phase operating mode 451.

In the arbitration phase 451, using an identifier (ID) with, for example, Bits ID28 to ID18 in the arbitration field 453, it is negotiated between the participating stations 10, 20, 30 which participating station 10, 20, 30 would like to send message 45, 46 with the highest priority and thus have exclusive access to Bus 40 of Bus 1 system to transmit in the next data phase 452. In the arbitration phase 451 a physical layer is used as for CAN and CAN-FD. The physical layer corresponds to the bit transmission layer or layer 1 of the known OSI model (Open Systems Interconnection module).

An important point in phase 451 is that the known SCMA/CR method is used which allows simultaneous access of the participating stations 10, 20, 30 to the bus 40 without the higher priority message 45, 46 being disturbed. . This makes it possible to advantageously use other relatively simple bus 10, 20, 30 participant stations which can be added to the Bus 1 system.

The SCMA/CR method results in recessive states on Bus 40 which will be oversubscribed by the other participating stations 10, 20, 30 at dominant level or dominant state on Bus 40; in the recessive state, in the various participating stations 10, 20, 30 there is a strongly ohmic situation which results in longer time constants in combination with the parasites of the Bus circuit. This results in a limitation of the maximum bit rate of the current CAN-FD physical layer to approximately 2 Megabits per second in actual use in a vehicle.

In the data phase 452, next to a part of the control field 454, the useful data of the CAN-XL frame 450 is sent, that is to say the message 45 of the data field 455 as well as the field checksum field 456. In the checksums field 456 one can have a checksum for the data of the data phase 452 including the padding bits which are inserted by the sender of the message 45, each time after a determined number of identical bits, in particular 10 identical bits as inverting bits. At the end of the data phase 452, we return to the arbitration phase 451.

At least one acknowledgment bit may be in the final field in the end of frame phase 457. In addition, there may be a sequence of 11 identical bits which indicate the end of the CAN XL frame 450. With at least one minus one acknowledgment bit, it can be indicated whether or not the receiver has detected an error in the received CAN XL 450 frame or the received message 45.

The sender of the message 45 begins the transmission of bits of the data phase 452 on the first Bus 40 only when the participant station 10 has won the arbitration as sender and the participant station 10 as sender thus has exclusive access. to Bus 40 of Bus System 1 for transmission.

Thus, the participating stations 10, 30 use in the arbitration phase 451 as the first communication phase, in part and in particular up to the FDF bits (inclusive), a known CAN/CAN-FD format according to the ISO11898-1 standard: 2015. However, compared to CAN or CAN-FD in data phase 452 as the second communication phase, there is a marked increase in data transmission speed, in particular, beyond 10 Megabits per second. In addition, the size of the useful data per frame can be increased, in particular, by 2K bytes or any other value.

There shows on the left side that the participating stations 10, 20, 30 emit in arbitration phase 451 the signals CAN_H, CAN_L on the Bus 40 which alternate with at least one dominant state 401 or at least one recessive state 402. After the arbitration in the arbitration phase 451, one of the participating stations 10, 20, 30 is the winner. Assuming that the participant station 10 has won the arbitration, the transmission/reception installation 12 switches the participant station 10 into its physical layer at the end of the arbitration phase 451 from a first slow mode of operation ( SLOW) in a second operating mode (FAST_TX) because the participant station 10 is the transmitter of the message 45 in the data phase 452. The transmitter module 121 then generates, in the data phase 452, that is to say say in the second operating mode (FAXT_TX) according to a TxD transmission signal, successively and thus in series the L0 and L1 states for the CAN_H, CAN_L signals on the Bus 40. The frequency of the CAN_H, CAN_L signals can be augmented in data phase 452 as seen on the right side of the . Thus, the net speed of data transmission in the data phase 452 is increased compared to that of the arbitration phase 451. On the other hand, the transmission/switching installation 12 switches the participant station 30 from its physical layer at the end of the arbitration phase 451, from the first slow operating mode (SLOW) to a third operating mode (FAST_RX) since the participant station 30 is only a receiver in the phase 452, i.e. say that he is not a sender in the frame 450. At the end of the arbitration phase 451, all the transmission/reception installations 12 switch the mode of operation of the participating stations 10, 30 to the first mode of slow operation (SLOW). Thus, all the transmission/reception installations 12 also switch their physical layer.

According to , in the ideal case, in the arbitration phase 451 there will be on the Bus 40 a difference signal VDIFF=CAN_H-CAN_L with values of VDIFF=2V for the dominant states 401 and VDIFF=0V for the recessive states 402. This appears on the left side of the . On the other hand, in the data phase 452 we will have on the Bus 40 a difference signal VDIFF=CAN_H-CAN_L with states L0, L1 as it appears on the right side of the . State L0 has a value VDIFF=1V. State L1 has a value VDIFF=-1V.

The receiver module 122 can distinguish the states 401, 402 or L0, L1 respectively with two of the reception thresholds T1, T2, T3 which are located in the ranges TH_T1, TH_T2, TH_T3. In addition, a reception threshold T4 can be used. To distinguish the states or the voltage levels on the Bus 40, it is possible to operate the receiver module 122 continuously over time or even to detect the signals of the or the at times t_A. Alternatively or additionally, detection of the RxD receive signal generated by the receiver module 122, more specifically the RxD/Bits levels in the communication control facility 11 at the instant of the detection point (Sample- Dot) t_A. To exploit the VDIFF and/or CAN_H, CAN_L signals, the receiver module 122 uses, in the arbitration phase 451, the reception threshold T1, for example, equal to 0.7 V and the reception threshold T2, for example, equal to at -0.35V or else the reception threshold T4 equal, for example to +0.35 V.

The reception threshold T2 is used at least for a predefined duration TA which corresponds to the arbitration. On the other hand, the receiver module 122 in data phase 452 uses the reception threshold T3 to exploit the VDIFF and/or CAN_H, CAN_L signals. When switching between the first to the third operating mode (SLOW, FAST_TX, FAST_RX), which have been previously described with reference to the , the receiver module 122 respectively switches the reception thresholds T1, T2, T3, T4 as described. It is also possible to switch between the reception thresholds T2, T4 during the arbitration phase 451. For example, the thresholds of the reception module 122 can be switched by an installation, in particular the control circuit 158 of the . The system recognizes a change in the data coding of the TxD send signal. In particular, an NRZ coding can be marked in the transmission signal TxD indicating that it is necessary to switch to arbitration phase 451 (SLOW). In particular, a PWM coding in the TxD transmission signal can indicate the operating mode to which the data phase 452 must be switched, namely the FAST TX operating mode if the participant station is the transmitter of the frame 450 or the FAST RX operating mode if the participant station is only the receiver of frame 450.

The reception threshold T2 is used to recognize if the Bus 40 is free, when the participant station 10 is new in communication on the Bus 40 and tries to integrate the communication of the Bus 40. The reception threshold T2 is called in the standard of CAN OOB (=Out-of-Boundary=Out-of-Boundary). The conditions for a non-circulating CAN-XL Bus are that there is no dominant state 401 which typically has a voltage difference VDIIF=2V. Thus, the reception threshold T1 must not be exceeded, for example equal to 0.7 V. In addition, there must not be a level according to the state L1 and which corresponds, characteristically, to a voltage difference VDIFF=-1V. Thus, the reception threshold T2 must, for example, not be exceeded downwards to -0.35V.

Each participant station 10, 30 switches the mode of operation of the transmission/reception installation 12 to the mode of operation of the arbitration phase 451 if the participant station 12 is new in communication on the Bus 40.

The connection of the participant station 10 may be, on the one hand, necessary if the participant station 10 was initially started and must be integrated into the communication on the Bus 40. On the other hand, the connection of the participant station 10 may be necessary if the participant station 10 seeks after a Bus communication fault, to reintegrate a communication with the Bus 40. It is only when it has detected that the Bus is free that the participant station 10 will be able to transmit in the cases indicated , itself data, in particular messages 45, 47 on the Bus 40.

The reception threshold T4 is used to recognize manipulations in the Bus system 1 as will be described more precisely below. The reception threshold T4 is activated in the arbitration phase 451 when the arbitration is finished or at the end of a frame 450 before the arbitration begins for a new frame 450.

Table 1 given below indicates the values that can be set for the various reception thresholds on Bus 40 according to the CiA610-3 standard for CAN XL. The VDIFF_min value sets the lower limit for the different ranges TH_T1, TH_T2, TH_T3; this lower limit is the minimum for the corresponding reception thresholds T1, T2, T3 in volts V. The VDIFF_typ value indicates the value that is set, typically in V or usually for the corresponding reception thresholds T1, T2, T3. DIFF_max indicates the upper limit for the various ranges TH_T1, TH_T2, TH_T3, upper limit which is the maximum setting of the corresponding reception thresholds T1, T2, T3 in V.

Table 1: Tolerance ranges of reception thresholds T1, T2, T3

In addition, the transmission/reception installation 12 of the can branch as a variant of the reception threshold T2, the reception threshold T4 of the . The reception threshold T4 can have a value of the order of VDIFF=+0.35V. In particular, the reception threshold T4 has a value in a range from VDIFF_min=+0.25 V up to VDIFF_max=+0.45V.

The receiver module 122 captures the reflections and/or the oscillations on the bus strands 41, 42 using the reception threshold T4. The reception threshold T4 is chosen so that the reflections can be recognized in Bus 40. If there is an intervention in the direction of manipulation in the Bus 1 system, the signal curves vary on the CAN_H- CAN_L. This also changes the voltage difference VDIFF=CAN_H-CAN_L. Exploiting variation is the basis for capturing and detecting network manipulations described above. For operation, the reflections and/or oscillations on the Bus strands 41, 42 are compared with the manipulations with reflections and/or oscillations on the Bus strands 41, 42 after the manipulation. The differences in the voltage difference VDIFF before and after a manipulation can be presented in simulation and/or by measurements. Participant station 10 is designed for this.

There shows the basic structure of the participant station 10 with the communication control installation 11 and the transmission/reception installation 12.

The communication control facility 11 has a protocol controller 111 and a clock 112 which can receive signals from the transmission/reception facility 12. The protocol controller 111 and the clock 112 are respectively provided to detect the signals in communication with the Bus system 1 and for measuring and exploiting the pulse widths of the signals for the communication in the Bus system 1. The clock 112 indicates the cadence for the communication in the Bus system 1.

The protocol control 111 establishes and interprets the messages 45, 46, 47 of the Bus 40 with a communication standard. The communication standard may in particular be CAN SIC or CAN LX as described above. For this, the communication control installation 11, in particular its protocol controller 111 generates the TxD signal and sends this TxD signal to the transmission/reception installation 12 as described previously. The communication control installation 11 exploits the RxD signal as described above. The protocol controller 111 has an operation block 1111 for a CA2 signal from the transmit/receive facility 12, a memory block 1112 for a CA2 signal from the transmit/receive facility 12, a memory block 1112 and a manipulation reaction block 1113. Memory block 1112 saves, for example, signal CA2 as a reference value CA2_0 upon receipt of a signal CA2 from Bus 40 after the Bus 1 system is powered up. The reference CA2_0 corresponds to the emission spectrum of the unmanipulated Bus 40.

Clock 112 may also have an operating block 1121 for the CA2 signal from transceiver 12, a memory block 1122, and a manipulation feedback block 1123. Operating block 1121 has the same function as operating block 1111. Memory block 1122 has the same function as memory block 1112. Handling reaction block 1123 has the same function as handling reaction block 1113. Thus, the signal CA2 of the transmit/receive facility 12 can be transmitted for operation to protocol controller 111 and/or clock 112.

The transmitter module 121 of the transmission/reception installation 12 is represented in a very simplified way. The transmitter module 121 is connected directly to the Bus 40 to send the TxD transmitter signal from the communication control facility 11 to the Bus 40, to generate the signals according to the on Bus 40.

The receiver module 122 of the transmission/reception installation 12 has a driver 1221 for the RxD digital reception signal, a logic circuit 1222, a driver 1225 for a CA2 signal and a reception circuit 15. The reception circuit 15 has a first receive comparator 151 which outputs signal CA1, a second receive comparator 152 which outputs signal CA2, a receive stage 153, a bus pre-voltage source (Bus-biasin) 154, terminals 155, 156 and a control circuit 158. The receive comparators 151, 152 are each a low voltage comparator.

Receiver circuit 15 is connected between bus B0 and logic circuit 1222. Driver 1221 is connected to the output of logic circuit 1222.

38 The 1221 driver drives or sends the RxD receive digital signal to the communications control facility 11. The 1225 driver drives or outputs the CA2 signal to the communications control facility 11. The CA2 signal can be transmitted to a additional connection C2 of the transmission/reception installation 12 and an additional connection of the communication control installation 11 via installation 12 to installation 11.

The output signal CA2 can be transmitted directly or filtered to the additional connection C2 of the transmission/reception installation 12 to the communication control installation 11. The connection C2 can be an additional connection C2 of the installation of transmit/receive 12. As a variant, branch C2 can be an existing branch, for example, the standby branch (STB) used in multiplexing.

In the receiver circuit 15, the receiver stage 153 is connected to the Bus 40. In Bus 1 operation, the receiver stage 153 generates the signals S_1, S_2 from the CAN signals to transmit them to the first reception comparator 151. The first reception comparator 151 generates a comparison output signal CA1 from the signals S_1, S_2. Signal CA1 is sent at connection 155 to logic circuit 1222.

Furthermore, in operation of the Bus 1 system, the receiver stage 153 additionally generates the signals S_3, S_4 from the signals CAN_H, CAN_L and transmits these to the second receiver comparator 152. The second receiver comparator 152 generates a signal comparison output CA2 from signals S_3, S_4. Signal CA2 is output from branch 156 to logic circuit 1222. In addition, signal CA2 is output from branch C2 to communication control facility 11 as previously indicated.

The comparator output signal CA1 depends on the reception threshold which has been activated in the first comparator 151. For this, the reception circuit 15 has a control circuit 158 which sets the reception threshold T1 ( ) or the reception threshold T3 ( ) in the receiver comparator 151. This will be described more precisely using the and some with reference to the second comparator 152.

The comparator output signal CA2 depends on the mode of operation of the transmission/reception installation 12, more precisely on the second comparator 152. The control circuit 158 or a second control circuit 158 controls the adjustment of the reception threshold T2 ( ) or the reception threshold T4 ( ) in the receive comparator 152. This will be further described with the aid of Figures 6 and 7.

The logic circuit 1222 is produced according to the mode of operation of the transmission/reception installation 12 to transmit the signal CA1 and the signal CA2 to the driver 1221 or only the signal CA1 to the driver 1221. For this, the logic circuit 1222 has at least one AND gate. Alternatively, logic circuit 1222 has other logic components to perform the function described below for receiver module 122.

As shown in , the receiver stage 153 further has a first input filter 1531 for the first comparator 151, a second input filter 1532 for the second comparator 152 and a voltage divider 1533. The voltage divider 1533 is a resistive voltage or resistor voltage divider.

The voltage divider 1533 is supplied with electrical voltage by the Bus voltage source (Bus-biasing) 154. The Bus voltage source 154 usually supplies a CAN_SUPPLY/2 voltage to the receive stage 153; more precisely it is about the tension divider 1533. Usually, one has CAN_SUPPLY=5V. In this case, the Bus voltage source 154 provides a voltage of 2.5 V to the receiver stage 153. The voltage of the Bus voltage source 154 can notably be set to 2.5 V for the recessive state. 402 ( ).

Voltage divider 1533 has first and second resistors R_CH1, R_CH2 for the CAN_H Bus signal. Additionally, voltage divider 1533 has a third and a fourth resistor R_CL1, R_CL2 for the CAN_L Bus signal. The voltage divider 1533 divides the Bus voltages generated from the CAN_H, CAN_L signals to values that the comparators 151, 152 can process. The resistor circuit of the voltage divider resistor network 1533 has a symmetrical structure.

The first resistor R_CH1 is connected by its end to the bus strand 41 (CANH). The other end of resistor R_CH1 is connected in series with the second resistor R_CH2. The third resistor R_CL1 is connected by one end to the Bus strand 42 (CANL). Its other end of the third resistor R_CL1 is connected in series with the fourth resistor R_CL2. The junction of the resistors R_CH é, R_CL2 is connected to the source of Bus 154.

The junction of resistors R_CH1, R_CH2 is connected to a resistor R_filter_CH_A of input filter 1531 and a resistor R_filter_CH_B of input filter 1532 for the CAN_H signal path. The link between the resistors R_CL1, R_CL2 is connected to a resistor R_filter_CL_A of the input filter 1531 and to a resistor R_filter_CL_B of the input filter 1532 for the CAN L signal path.

The first input filter 1531 for the first comparator 151 has a first RC element for the CAN_H signal path and a second RC element for the CAN_L signal path. The first element has, in addition to the resistor R_filtre_CH_A, a capacitor C_filtre_CH_A. The second element RC has, in addition to the resistor R_filtre_CL_A, a capacitor C_filtre_CL_A. Capacitors C_Filtre_CH_A, C_filtre_CL_A are connected by one end to ground or to connection 44 of CAN_GND.

The second input filter 1532 for the second comparator 152 has a first RC element for the CAN_H signal path and a second RC element for the CAN_L signal path. The first element RC has, in addition to the resistor R_filtre_CH_B, a capacitor C_filtre_CH_B. The second element RC has, in addition to the resistor R_filtre_CL_B, a capacitor C_filtre_CL_B. Capacitors C_filtre_CH_B, C_filtre_CL_B are connected by one end to ground or to connection 44 of CAN_GND.

Thus, the two comparators 151, 152 use the same voltage divider 1533. This common use of the voltage divider 1533 allows the simultaneous exploitation or at the same time of two voltage thresholds. The control circuit 158 makes it possible to switch the reception thresholds T1, T3 in the first comparator 151 using a signal sw_th1. Furthermore, the control circuit 158 allows the switching of the reception thresholds T2, T4 in the second comparator 152 using the signals sw_th2. This is represented in Table 2 as the association of the output signals CA1, CA2 of the comparators 151, 152 with the voltage thresholds T1, T2, T3, T4.

Table 2: Example of an association of output signals CA1, CA2 of comparators 151, 152 and voltage thresholds T1, T2, T3, T4.

The receiver circuit 15 exploits the receiver thresholds T1, T2 or the receiver thresholds T1, T4 in the arbitration phase 451 at the same time, for which the transmission/reception installation 12 is switched to slow operating mode ( SLOW). After the switching of the reception threshold in the first and the second comparator 151, 152, the reception thresholds T3, T2 are simultaneously exploited in the data phase 452 for which the transmission/reception installation 12 is switched in the one of the operating modes FAST_TX, FAST_RX.

The first comparator 151 can be a known CAN receiver comparator. The signal CA1 at the output of the comparator 151 is sent only by the logic circuit 1222 by the connection of the signal RxD. In addition, the first comparator 151 can be switched as described more precisely below for the second comparator 152.

The second input filter 1532 of the second comparator 152 performs less strong low-pass filtering than the first input filter 1531 for the first comparator 151. In other words, the second input filter 1532 has for the path CAN_H signal path, a larger bandwidth than the first comparator 151. Thus, the second input filter 1532 has, for the CAN_H signal path, a higher frequency limit than that of the first comparator 151. In addition, the second input filter 1532 for the CAN_L signal path has a larger bandwidth than the first comparator 151. Thus, the second input filter 1532 has for the CAN_L signal path a higher cutoff frequency than that of the first comparator 151. In addition, the output of the second comparator 152 is not filtered or is less low-pass filtered than the output of the first comparator 151. This is possible because the main function of the second comparator 152 is to process, in the phase of data 452, the CAN-XL signals from another transmitting participant station with the bus states L0, L1 according to the . Bus states L0, L1 are transmitted with a higher bit rate and by the transmission/reception facilities 12 with a lower impedance. The property of the comparator 152 is additionally used in the arbitration phase 451 to detect manipulations in the Bus system 1. A participant station 10, 30 sender proceeds as follows:

The participating station 10, 30 verifies by arbitration during the time TA whether it will be able to send its frame 450 in the following data phase 452. For this, with the comparators 151, 152 it is checked whether another participating station would like to send a message 45, 46, 47 of higher priority. If this is not the case, Bus 40 is free. If it is guaranteed that the Bus 40 is free, the transmitting/receiving installation 12 can begin to transmit the frame 450 on the Bus 40. The second comparator 152 no longer has to check whether the Bus 40 is free. This is why before the data of the frame 450 is transmitted to the Bus 40 in the data phase 452, the second comparator 152 is only used to compare the evolution of the voltage difference VDIFF of greatest width of band has a reference value between 0V and 2V. For this, the control circuit 158 controls, using the signal sw_th2, the switching of the reception threshold of the receiver comparator 152 at T2=-0.35V to the receiver threshold T4 equal, for example, to +0.35V. The resulting CA2 signal is transmitted to the installation 11.

The comparison of the signal CA2 and the reference value CA2_0 is recorded in at least one of the memory blocks 1112, 1122 of the which detects the variations of the network of the bus system 1. The variations detected by the comparison with the reference value CA2_0 supposes manipulations of the network.

Thus, the signal CA2 of at least one of the operating blocks 1111, 1121 is exploited. This results in the exploitation of at least one of the operating blocks 1111, 1121, indicating the existence of a manipulation to cause at least one reaction in the corresponding manipulation reaction block 1112 , 1122 . The reaction is, for example, that the communication control device 11 switches off the transmission of the transmission signal TxD. An alternative or an additional reaction would be, for example, that the transmitting/receiving installation 12 cut off the transmission of the frame 450 on the bus 40. An alternative or an additional reaction could be, for example, also that the communication control unit 11 sends at least one fault frame 48. A variant or an additional reaction could, for example, also have the communication control unit 11 signal the manipulation to a microcontroller of a higher control unit of the participant station 10.

This makes it possible to recognize, in safety, the manipulations in the Bus 1 system. In addition, one can react, according to the case, to the manipulation.

There shows an example of the structure of the second comparator 152. The first comparator 151 could be made in the same way.

According to , the second comparator 152 has an operation mode unit 1520, a two-stage circuit which has a first pair of differential inputs 1521, a second pair of differential inputs 1522 as well as a first to third current mirror 1525, 1526, 1527 as well as an output buffer 1528. The output buffer 1528 drives the output signal CA2.

The operating mode setting unit 1520 is controlled with the switching signal sw_th2 by the control circuit 158. The switching signal sw_th2 switches the comparator 152 according to the operating mode by which the receiver stage 153 receives the signals CAN_H , CAN_L and more precisely, interprets them as described above.

The circuit with two stages of the has the following elements, namely a first to fifth current source I1, I2, I3, I4, I5, a first and a second transistor TR1, TR2 which form a first pair of differential inputs 1521, a resistor Rdiff, a first and a second collector resistor RC1, RC2, a third and a fourth transistor TR5, TR6 as emitter-followers, a fifth and sixth transistor TR7, TR8 as level switch, a seventh and eighth transistor TR9, TR10 which form the second pair of differential inputs 1522, the first current mirror 1525 with the transistors TR11, TR12, the second current mirror 1526 with the transistors TR13, TR14, the third current mirror 1527 comprising the transistors TR15, TR16. The transistors TR1, TR2, TR5, TR5, TR7, TR8 are npn bipolar transistors according to the example of the . The transistors TR9, TR10 in this example of the are pnp bipolar transistors. The transistors TR11, TR12, TR13, TR14, TR15, TR16 of this example of the are field effect transistors. The transistors TR11, TR12, TR13, TR14 of the first and of the second current mirror 1525, 1526 of this example of the are NMOS transistors, in particular, normally-blocking n-channel MOSFET metal-oxide field-effect transistors. The transistors TR15, TR16 of the third current mirror 1527 of this embodiment of the are PMOS transistors, in particular normally blocking p-channel MOSFET metal-oxide field-effect transistors.

The circuit with two stages of the is supplied with CAN_SUPPLY voltage by terminal 43. Each of the collector resistors RC1, RC2 is connected by one of its ends to terminal 43. In addition, the collectors of transistors TR5, TR6 are connected to terminal 43. Furthermore, the fifth current source 15 and the third current mirror 1527 are connected by the transistors TR15, TR16 to terminal 43. The fifth current source I5 feeds the second pair of differential inputs 1522 from the seventh and eighth transistor TR9, TR10.

The first current source I1 is connected to ground and its other end is connected to the emitter of the first transistor TR1 as well as to one end of the resistor Rdiff. The second current source I2 is connected to ground and by its other end, to the emitter of the second transistor TR2 and to the other end of the resistor Rdiff. Current sources I1, I2 correspond to the operating point of transistors TR1, TR2. The reception threshold T2 or the reception threshold T4 are set according to the value of the switching signal sw_th2 of the current sources I1, I2 and of the resistor Rdiff as well as according to table 2 indicated above.

The base of the third transistor TR5 resides in the connection between the first transistor TR1 and the first collector resistor RC1. The base of the fourth transistor TR6 is connected to the junction between the second transistor TR2 and the second collector resistor RC2. The emitter of the third transistor TR5 is connected to the fifth transistor TR7 by its collector and its base. The emitter of the fourth transistor TR6 is connected to the sixth transistor TR8 by its collector and its base. The emitter of the third transistor TR5 is connected to the current source I3. The transmitter of the fourth transmitter is connected to the current source I4.

The base of the seventh transistor TR9 is connected to the junction between the fifth transistor TR7 and the third current source I3. The base of the eighth transistor TR10 is connected to the junction between the sixth transistor TR8 and the fourth current source I4. The emitters of transistors TR9, TR10 are connected to current source I5. The collector of the seventh transistor TR9 is connected to the transistor T11 of the first current mirror. The collector of the eighth transistor TR10 is connected to the transistor T13 of the second current mirror.

Transistor T12 of first current mirror 1525 is connected between transistor T15 of third current mirror 1527 and ground. Transistor T14 of second current mirror 1526 is connected between transistor T16 of third current mirror 1527 and ground. Output buffer 1522 is connected by its input to transistor TR14 of the second current mirror and to transistor TR16 of the third current mirror.

In the example of figures 5 to , the control circuit 158 is made as a transistor and comprises at least one transistor. The transistor is in particular an NMOS transistor. The abbreviation “NMOS” designates an n-channel MOSFET transistor; the abbreviation "MOSFET" stands for a metal-oxide field effect transistor. The control circuit 158 controls the operation mode setting unit 1520 by a "high" level signal sw_th2 so that the operation mode setting unit 1520 sets the reception threshold T2 of the , as already described.

This means that, according to FIGS. 5 to FIG. 7, the first comparator 151 provides, independently of the mode of operation of the transmission/reception installation 12, a signal CA1 indicating that in the two communication phases, a message 45 has been operated with different reception thresholds. Thus, the signals S_1, S_2 will be exploited in the first comparator 151 by using the reception threshold T1 in the arbitration phase 451 and by using the reception threshold T3 in the data phase 452. On the other hand, for the second comparator 152, the signal CA2 must have at least for a given duration TA an arbitration phase 451 and a data phase 452 to exploit a message 45 with the reception threshold T2 and only if, for a duration which is outside the preset time TA ( ) and of the arbitration phase 451, there is a message 45 which is exploited with the reception threshold T4. If the “high” level signal sw_th2 is applied to the operating mode setting unit 1520, the second comparator 152 provides a signal CA2 for which the signals S_3, S_4 will be exploited using the reception threshold T2. On the other hand, the first comparator 151 supplies, independently of the signal sw_th2 in arbitration phase 451, a signal CA1 for which the signals S_1, S_2 will be exploited by using the reception threshold T1. In other words, the first comparator 151 supplies, in arbitration phase 451, the recognition of the threshold T1 and the second comparator 152 supplies either the recognition of the threshold T2 or that of the threshold T4. The reception threshold T4 is applied if, in the arbitration phase 451, there has been no arbitration. In particular, the reception threshold T4 is activated only if, in arbitration phase 451, the arbitration is terminated, but not switched to data phase 452.

If the signal sw_th2 of the operating mode setting unit 1520 has, on the other hand, the value "low", the second comparator 152 supplies a signal CA2 for which the signals S_3, S_4 will be exploited using the reception threshold T4 . On the other hand, the first comparator 151 again supplies, independently of the signal sw_th2, a signal CA1 for which the signals S_1, S_2 have been exploited by using the reception threshold T1. In other words, the first comparator 151 provides the detection of a threshold T1 and the second comparator 152 provides the detection of the threshold T4.

If, on the other hand, the signal sw_th1 of the operating mode setting unit 1520 of the comparator 151 has the value "low", the first comparator 151 supplies a signal CA1 for which the signals S_1, S_2 have been evaluated. using the reception threshold T3. On the other hand, the second comparator 151 again supplies, independently of the signal sw_th1, a signal CA2, for which the signals S_3, S_4 have been exploited by using the reception threshold T2. In other words, the first comparator 151 provides the detection of the threshold T3 and the second comparator 152 provides the detection of the threshold T2.

The embodiment described of the receiver circuit 15 makes it possible to check two different reception thresholds for the reception thresholds T1, T2, T3, T4 independently of each other and thus and at the same time. In addition, with the exploitation circuit 158 it is possible to switch between two reception thresholds among the reception thresholds T1, T2, T3, T4. This makes it possible either to check simultaneously and independently of each other, the reception thresholds T1, T2 according to the , or to check independently and at the same time the reception thresholds T1, T4 according to the or even the reception thresholds T3, T2 according to the , independently of each other and at the same time.

The operating mode adjustment unit 1520 thus adjusts the reception thresholds T2, T3 according to the operating mode used hitherto (SLOW, FAST_TX, FAST_RX) of the transmission/reception installation 12 and/or the mode of operation thus requested for the second comparator 152.

According to a first modification of the previous embodiment, at least one of the exploitation blocks 1111, 1121 not only exploits the signal CA2 by using the reference value CA2_0. But, in addition, at least one of the exploitation blocks 1111, 1121 also exploits the reception signal RxD by using the reference value CA2_0. The timing of CA2, RxD signal input for network manipulation determination may be the same. As the moment of the capture of the signals CA2, RxD to determine the manipulations of the network is located in the arbitration phase 451, the signal RxD has been established using the reception threshold T1. The reception threshold T1 is typically located at 0.7 V, as described above with reference to Table 1. Thus, it is possible to have an even more precise determination of the existence or not of manipulations. If the exploitation of at least one of the exploitation blocks 1111, 1121 shows that there is a manipulation, the corresponding manipulation reaction block 1112, 1122 produces at least one corresponding reaction as described above. -above.

According to a second modification of the previous embodiment, a signal sw_th1 applied to the operating mode setting unit 1520 sets the reception threshold T1 in the comparator 151 with the low value "low" and a signal sw_th1 of value high "high" sets the reception threshold T3 in the comparator 151. The signal sw_th2 can be modified as described previously.

According to a third modification of the previous example embodiment, a signal sw-th2 fixed by the rate adjustment unit 1520, a “low” value for the reception threshold T2 in the comparator 152 and a signal sw_th2, of value "high", sets the reception threshold T4 in the comparator 152. The signal sw_th1 can be modified as described above.

There shows a transmission/reception installation 12A according to a second exemplary embodiment. Transmit/receive installation 12A can be used instead of a transmit/receive installation 12 in the Bus 1 system of the .

The transmission/reception installation 12A has a transmitter module 1210 and a receiver module 122. The transmitter module 1210 is composed of four parts in the same way as the transmitter module 121 of the first example embodiment. Under these conditions, the remainder of the description will be limited to the differences with respect to the first example embodiment.

Unlike the first exemplary embodiment, the transmitter module 1210 generates the signals CAN_H, CAN_L for the two communication phases 451, 452 on the Bus 40, as will be described below, with the aid of FIGS. 9 to 12 Thus the transmission/reception installation 12A is in the arbitration phase 451, in an SIC operating mode. Alternatively, the transmitter module 1210 can, however, from time to time generate the signals CAN_H, CAN_L for the two communication phases 451, 452 on the Bus 40 as described above using the and some . The transmission/reception installation 12A is in the arbitration phase 451 in the “low” SLOW operating mode.

There shows an example of part of the digital transmission signal TxD which the transmitter module 121 receives in the arbitration phase 451 from the communication control installation 11 and generates, from this, signals CA_H, CAN_L for the Bus 40. In , the transmit signal TxD varies from an LW state (low state) to the high state HI and again a return to the LW state (low state).

In the ideal case, the RxD receive signal is identical to the TxD transmit signal. In such an ideal case, there is no transmission delay/travel time, in particular via Bus 40, and thus there is no possible reception error.

As shown more precisely by , the transmitter module 121 can generate, with the transmission signal TxD of the in the CAN SIC or CAN XL operating modes, the CAN_H, CAN_L signals of the for the bus strands 41, 42. Unlike the , for the signals of the , we also have a 403 (sic) state. State 403 (sic) can have a different duration as for state 403_0 (sic) when going from state 402 (rec) to state 401 (dom) and for state 403_1 when going from state 401 (dom) to state 402 (rec). The 403_0 (sic) state is shorter in time than the 403_1 (sic) state. To generate the signals according to the , the transmission module 1210 is switched to operating mode sic (mode).

Passing the brief sic state 403_0 is not necessary according to the CiA610-3 standard for CAN XL and the state independent of the nature of the implementation. The duration of the "long" state 403_1 (sic) for CAN-SIC and also for the operating mode SIC for CAN-XL is defined as follows: t_sic 530ns starting with the rising edge of the TxD transmission signal from the .

In the "long" state 403-1 (sic), the 1210 transmitter module must match the impedance between Bus strands 41 (CANH) and 42 (CANL) as well as possible to the characteristic wave resistance Zw of the Bus line used. We have Zw=100Ohm or 120Ohm. This adaptation avoids reflections and thus allows operation at higher bit rates. For simplicity, we will always mention the 403 (sic) state or the 403 security sic state below.

There shows an example of another portion of the TxD digital transmit signal received by transmitter module 1210 in data phase 452 from communications control facility 11 ( ) and generates with them the signals CAN_H, CAN_L for Bus 40. At the , the transmit signal TxD changes several times from state HI (High) to low state LW (low) and back to state HI (high) and so on.

As shown more specifically by the , the transmitter module 1210 generates for the TxD transmission signal of the , the signals CAN_H, CAN_L, for the Bus strands 41, 42 so that the L0 state develops for an LW (low=Low) state and the L1 state for a (high) HI state.

It is possible to use for both Bus states L0, L1 at least from time to time in the absence of a dominant and recessive Bus state, but, instead, a first Bus state and a second Bus state Bus, which operates both Buses. An example of such a Bus system is a CAN XL Bus system.

The receiver module 122 can also receive the signals according to the and the in the two different switching phases, namely the SIC operating mode or the arbitration phase 451 and the data phase 452. For this, the receiver module 122 switches the reception thresholds T1, T12, T3, T4 for the different modes of operation as described by way of example.

The operating mode control unit 1537 thus controls the adjustment of the reception thresholds T1, T2, T3, T4 according to the operating mode requested at the moment (SIC, FAST_TX, FAST_RX) of the transmission/reception installation 12A and/or the operating mode of the second comparator 152.

In addition, the transmitter module 1210 is designed to improve the evaluation of the network manipulation in a fixed area or bit of the arbitration phase 451 to send the stateless CAN_H, CAN_L signals sic 403. A first example of the range fixed is the range after the end of the arbitration has been completed in the arbitration phase 451, however the data phase 452 is not completed. A second example of the fixed range is a bit of the arbitration phase 451, in particular the AL1 bit of the .

In a participant station 10, the communication control installation 11, the protocol controller 111 and/or the clock 113 guarantee that the participant station 10 is the only transmitter of the Bus system 1. The communication control installation communication 11, in particular the protocol controller 111 and/or the clock 113 thus check whether the arbitration in the arbitration phase 451 is finished. In addition, it is guaranteed that the 12A transmission/reception installation, in particular the 1210 transmitter module, is in SIC operating mode.

If the transmit/receive installation 12A changes from the data phase 452 operating mode, that is to say from the Fast-TX-/Fast-RX operating mode or SIC operating mode, the installation transmit/receive 12A knows that frame 450 is coming to an end. The transmission/reception installation 12A which arrives from the Fast-TX operating mode is controlled by the communication control installation 11, in particular by the protocol controller 111 or the clock 113 so that after the change of mode from Fast-TX operating mode to SIC operating mode, it still sends the AL1 bit as previously indicated with reference to the . At the end of this bit AL1, there is a rising blank in the TxD transmission signal which exceptionally generates a recessive state (rec) 402 without sic state 403. In this fixed transition from state (dom) 401 to (rec ) 402, the transmission/reception installation 12A, in particular the transmitter module 1210 will not use the sic function. Instead, only a 403_0 transition is generated or the CAN_H, CAN-L signals are generated for the AL1 bit as shown in .

During the "slow" arbitration phase (max. 1 Mbit/s) the stateless transmission (sic) 403 does not create any recognition problem in the communication control installations 11, 21 of the Bus system 1 in particular for the protocol controller 111 or clock 113.

In the fixed range or the bit of the arbitration phase 451, in particular for the falling edges of the signals CAN_H, CAN_L for the bit AL1, when the transmitter module 1210 emits the signals CAN_H, CAN_L without state 403, the typical reflections of network are emphasized more strongly. Thus, the blocks 1111, 1121 can more easily recognize a variation in the behavior of the Bus 40 by manipulation. In the fixed range or in bit of the arbitration phase 451, when the transmitter module 1210 emits the signals CAN_H, CAN_L without state sic 403, we have signal curves as for the classic CAN/CAN-FD.

There shows a transmission/reception installation 12B according to a third embodiment. The transmission/reception installation 12B can be used instead of a transmission/reception installation 12A of the in the Bus 1 system of the .

Unlike the previous exemplary embodiment, the transmit/receive facility 12B has a protocol controller 159 equipped to interpret part of the protocol of the frame 450. The protocol controller 159 has reduced functional significance compared to to that of the protocol controller 1111.

The protocol controller 159 is designed to determine the instant of control and the transmission of the (rec) state 402 without the (sic) state 403 by the transmitter module 1210. The protocol controller 159 monitors the receive signal RxD. In the example of the , the protocol controller 159 monitors for this purpose the output of the first controller 151.

In this embodiment, the protocol controller 159 commands the transmit module 1210 so that the transmit module 1210 transmits within the fixed range or the bit of the arbitration phase 451, the signals CAN_H, CAN_L without the state sic 403. The protocol controller 159 commands the transmission module 1210 in a corresponding manner, in particular for the falling edges of the signals CAN_H, CAN_L for the bit AL1, to generate no state (sic) 403 or only a transition 403_0.

In this way, blocks 1111, 1121 can also detect a variation in the behavior of Bus 40 by manipulation as previously described. Thus, with at least one of the blocks 1113, 1123, the desired reaction can be triggered as described above.

There shows a transmission/reception installation 12C according to a fourth exemplary embodiment. The transmission/reception installation 12C can be used instead of one of the transmission/reception installations 12A, 12B of the or the in the Bus 1 system of the .

Unlike the previous embodiment, the transmission/reception installation 12C has a logic block 160 connected to the outputs of the comparators 151, 152. The logic block 160 uses the signals CA1, CA2 of the comparators 151, 152 to recognize a modification of the course of the signal of the voltage difference VDIFF. If the two comparators 151, 152 are in good agreement, this makes it possible to detect the random falsifications which occur as intrusions or manipulations, in order to eliminate them. However, the comparators 151, 152 are set to different reception thresholds among the reception thresholds T1, T2, T3, T4 as described above using table 2.

The logical combination of the signals CA1, CA2 of the comparators 151, 152 which are set to different reception thresholds among the reception thresholds T1, T2, T3, T4 makes it possible to detect four different states. Logic block 160 thus forms a 2-bit AD converter.

Thus, the blocks 1111, 1121 exploit the output signal CA_160 of the logic block 160. The output signal CA_160 contains the information of the reception signal RxD and of the signal CA2.

In this way, blocks 1111, 1121 can also detect a change in the behavior of Bus 40 as a result of manipulations as previously described. Thus, with at least one of the blocks 1113, 1123, the desired reaction can be triggered as described previously.

There shows a 12D transmission/reception installation corresponding to a fifth embodiment. The transmission/reception installation 12D can be used instead of any one of the transmission/reception installations 12A, 12B, 12C of the or the or the in the Bus 1 system of the .

Unlike the previous example embodiment, the transmission/reception installation 12D has an operating mode input block 161 connected to the output of the first comparator 151. The operating mode input block 161 uses the signal CA1 from the comparator 151 to capture the mode of operation of the transmission/reception installation 12D.

The operating mode input block 161 is equipped to determine the instant of control and the transmission of the state (rec) 402 without the state (sic) 403 by the transmitter module 1210. For this, the block of operating mode input 161 monitors the RxD receive signal. In the example of the , the operation mode input block 161 monitors the output of the first comparator 151.

In this variant, the operating mode input block 161 inputs the transmitter module 1210 so that the transmitter module 1210 transmits in the fixed range or in at least one bit of the arbitration phase 451 the signals CAN_H, CAN_L without the sic state 403. In particular, at least one bit of the phase of arbitration 451 is bit AL1 so that at least for the falling edges of the signals CAN_H, CAN_L there is no transmission for the bit AL1 or only a shortened state (sic) 403.

Also, in this way, the blocks 1111, 1121 make it possible to detect a modification of the behavior of the Bus 40 by manipulation as described above. Thus, with at least one of the blocks 1113, 1123 the desired reaction is triggered as described.

There shows a reception circuit 150 of the transmission/reception installation 12 or 12A, 12B, 12C, 12D according to a sixth exemplary embodiment. The receiver circuit 150 can be used instead of the receiver circuit 15 of the in the Bus 1 system of the .

Unlike the first exemplary embodiment, the receiver stage 153 of the example of the has a first voltage divider 1535, a second voltage divider 1536, a first switching unit Sw1, a second switching unit Sw2, a third switching unit Sw3 and an operation mode setting unit 1537. The switching unit Operating mode setting 1537 may be equal to control circuit 158 of previous exemplary embodiments. The first and the second voltage divider 1535, 1536 are respectively supplied with the same voltage by the Bus voltage source 154 in particular a voltage of 2.5V for the recessive state 402 ( Or ).

The first voltage divider 1535 and the second voltage divider 1536 are resistive voltage dividers or resistance voltage dividers.

The first voltage divider 1535 has a first through seventh resistor R_CH1_A through R_CH_7_A for the CAN_H Bus signal. The first resistor R_CH_1_A is connected by one end to the Bus line 41 (CANH). Via its other end, the first resistor R_CH1_A is connected in series with the parallel circuit made up of the second resistor R_CH2_A and a series circuit of the third and fourth resistors R_CH_3_A, R_CH4_A. The junction of resistors R_CH3_A, R_CH4_A is connected to the end of the fifth resistor R_CH5_A. Moreover, the fourth resistor R_CH4_A is connected by its other end to one end of the sixth resistor R_CH6_A. The resistors R_CH5_A, R_CH6_A are connected by their other end to the seventh resistor R_CH7_A. The other end of resistor R_CH7_A is connected to the first switching unit Sw1. Switching unit Sw1 is also connected to ground and thus to connection 44.

The 1535 voltage divider has an eighth through twelfth resistor R_CL1_A through R_CL5_A for the CAN_L Bus signal. The eighth resistor R_CL1_A is connected by one end to the Bus line 42 (CANL). Its other end of the resistor R_CL1_A is connected in series with the parallel connection made up of the ninth resistor R_CL2_A and the series connection of the tenth and eleventh resistors R_CL3_A, R_CL4_A. The junction of resistors R_CL3_A, R_CL4_A is connected to one end of the twelfth resistor R_CL5_A. In addition, resistors R_CL2_A, R_CL4_A, R_CL5_A are respectively connected to the junction of resistors R_CH2_A, R_CH4_A, R_CH6_A.

The first input of the first comparator 151 is connected to the junction between the first and the second resistors R_CH1_A, R_CH2_A. The second input of the first comparator 151 is connected to the junction between the eighth and ninth resistors R_CL1_A, R_CL2_A.

The resistive path is connected to ground (terminal 44) by resistor R_CH7_A and adjusts the reception threshold T1 of the . To be able to switch to the reception threshold T3 according to Table 2 above, the first switching unit Sw1 controls the operating mode setting unit 1537 as will be described more precisely below. In this case, the logic circuit 1222 is designed so that in the arbitration phase 451, the two comparator signals CA1, CA2 are transmitted to the pilot 1221. In the data phase 452, only the comparator signal CA1 is transmitted to the pilot 1221.

The receiver module 122 of the uses the signals CAN_H, CAN_L, always with two reception thresholds, simultaneously, namely either with the reception thresholds T1, T2, or with the reception thresholds T1, T4 or with the reception thresholds T3, T2. It is also possible to have simultaneous operation with the reception thresholds T1, T3 as will be described below, more precisely. Moreover, the two reception thresholds operated simultaneously are operated independently of each other.

The second voltage divider 1536 of the has between one and seven resistors R_CL1_B to R_CL7_B for the CAN_H Bus signal. The first resistor R_CL_1_B is connected by one end to the Bus line 41 (CANL). The other end of the first resistor R_CL1_B is connected in series with the parallel circuit made up of the second resistor R_CL2_B and the series circuit of the third and fourth resistors R_CL3_B, R_CL4_B. The junction of resistors R_CL3_B, R_CL4_B is connected to one end of the fifth resistor R_CL5_B. The fourth resistor R_CL4_B is connected by its other end to a first end of the sixth resistor R_CL6_B. Resistors R_CL5_B, R_CL6_B are connected by their other end to one end of resistor R_CL7_B. The other end of resistor R_CL7_B is connected to second switching unit Sw2. The switching units Sw2 are additionally connected to ground via terminal 44.

The second voltage divider 1536 includes eight to fourteen resistors R_CH1_B through R_CH7_B for the CAN_L Bus signal. The first resistor R_CH1_B is connected by one end to the bus line 42 (CANH). Its other end of the first resistor R_CH1_B is connected in series to the parallel circuit made up of the ninth resistor R_CH2_B and a series circuit of the seventh and eleventh resistors R_CH3_B, R_CH_4B. The junction of resistors R_CH3_B, R_CH4_B is connected to one end of the twelfth resistor R_CH5_B. The junction of resistors R_CH2_B, R_CH4_B is connected to one end of the third resistor R_CH6_B. Moreover, resistors R_CH5_B, R_CH6_B are connected by their junction to one end of resistor R_CH7_B. The other end of resistor R_CH7_B is connected to the third switching unit Sw3. Switching unit Sw3 is additionally connected to ground and thus to terminal 44.

The first input of the second comparator 152 is connected to the junction of the first and the second resistors R_CH1_B, R_CH2_B. The second input of the second comparator 152 is connected to the junction between the eighth and ninth resistors R_CL1_B, R_CL2_B.

When the switching units Sw2, Sw3 are switched correspondingly, we will have the reception thresholds T2 or T4 or T3 of the for the resistive path with resistor R_CL7_B to ground or to terminal 44 and the second resistive path with resistor R_CH7_B to ground or to terminal 44.

For example, if switch unit Sw2 is switched so that the path from resistor R_CL_7_B to terminal 44 conducts and switch unit Sw3 is switched so that the path from resistor R_CH7_B to terminal 44 is not conductive, then the reception threshold T2 of the is set.

If, in this example, switch unit Sw2 is switched so that the path from resistor R_CL_7_B to terminal 44 is cut, and switch unit Sw3 is switched so that the path from resistor R_CH7_B to terminal 44 is conductive, then we have adjusted the reception threshold T4 of the .

Thus, the receiver circuit 150 can be controlled to adjust the reception thresholds T1 to T4 for the comparators 151, 152 as described above in relation to table 2.

It is possible, in the second voltage divider 1536, to adjust the reception threshold T3 of the . For this, switching unit Sw2 is switched so that the path from resistor R_CL7_B to terminal 44 is cut and switching unit Sw3 is switched so that the path from resistor R_CH7_B to terminal 44 is not driver. In this case, the receiver circuit 150 or the receiver module 122 can simultaneously verify the reception thresholds T1, T3. If switching between less receive threshold is requested than the above, receiver circuit 150 and/or receiver stage 153 will normally have a number other than three switching units Sw1, Sw2, Sw3. In particular, it is possible that the reception stage 153 comprises only one switching unit Sw1. Then, for one of the voltage dividers 1535, 1536 it is possible to switch between two reception thresholds and for the other voltage divider 1535, 1536 it is possible to set, in a fixed manner, a reception threshold. A few other combinations can also be considered.

If you want to switch between the switching thresholds with at least one of the switching units Sw1, Sw2, Sw3, you can connect at least one of the switching units Sw1, Sw2, Sw3 alternatively to ground via a resistor .

The resistor circuit in the resistor network of voltage dividers 1535, 1536 is a symmetrical structure.

To meet the input resistance requirement Rin on CANH and CANL, the paths of the resistors of the voltage dividers 1535, 1536 are halved due to the doubled structure. Thus, we have Rin_CANH and Rin_CANL=25kOhm..50kOhm. Typically, an input resistance Rin of 37.5 kOhm is chosen for the connection (pin) of the CAN_H signal and for the connection (Pin) for the CAN_L signal. In this case, the described resistance paths of the voltage dividers 1535, 1536 are implemented as follows. The path from CANH through resistor R_CH1_A of the first voltage divider 1535 to ground or to terminal 44 for CAN_GND has a resistance of approximately 2*37.5kOhm. The path from CANH through resistor R_CH1_B of the second voltage divider 1536 to ground or to terminal 44 for CAN_GND has a resistance of approximately 2*37.5kOhm. The path from CANL through resistor R_CL1_A of first voltage divider 1535 to ground or to terminal 44 of CAN_GND has a resistance of approximately 2*37.5kOhm. The path from CANL through resistor R_CL1_B of second voltage divider 1536 to ground or to terminal 44 for CAN_GND has a resistance of approximately 2*37.5kOhm.

As according to the previous table 1, for the thresholds T2, T3 and in particular also for the threshold T4 it takes half the tolerance (+/-100mV) than for the threshold T1 (+/-200mV), the resistances of the first divider resistors 1535, for example, for the first comparator 151 may be different from the resistors of the second voltage divider 1536. (Si surface) than the resistances of the first voltage divider 1535. This results in less dispersion of the reception thresholds as required by Table 1.

If, however, the first voltage divider 1535 is also made to switch between the thresholds T1, T3, as previously described, the resistors of the second voltage divider 1536 can be, for example, designed for the second comparator 152 like the resistors of the first voltage divider 1535. Thus, for example, the dimension of the surface of the semiconductors, in particular the silicon surface (Si surface) of the resistors of the second voltage divider 1536 is equal to the dimension of the surface of the semiconductors. conductors, in particular of the silicon surface (Si surface) of the resistors of the first voltage divider 1535. Thus, the dispersion of the reception thresholds is the same.

In the example of the , the switching units Sw1, Sw2, Sw3 each consist of a transistor, in particular an NMOS transistor. The abbreviation NMOS stands for an n-channel MOSFET transistor; the abbreviation MOSFET designates a metal-oxide field effect transistor. If the operation mode setting unit 1537 controls the switching unit Sw1 with a "high" level signal, the switching unit Sw1 is conductive, that is to say closed. In this case, resistor R_CL7_A is connected to ground (terminal 44). The resistive path passing through resistor R_CL7-A is connected to ground and corresponds to the reception threshold T1 of the as previously described.

If the operation mode setting unit 1537 controls the switch unit Sw1 with a "low" level signal, then the switch unit Sw1 is open, i.e. non-conductive. In this case, resistor R_CH7_A is cut off from ground (terminal 44), i.e. the assembly is cut off, which corresponds to the reception threshold T3 of the . The same remark applies correspondingly for the control of the switching units Sw2, Sw3 with a signal applied by the operating mode setting unit 1537 to set the reception thresholds T2, T3, T4 of the as previously described.

In connection with the comparators 151, 152 and the digital output signals CA1, CA2, generated by these, the same remark applies for an NMOS transistor as switching unit Sw1 or Sw2 or Sw3 as for the first example of realization and description of table 2.

Thus, the voltage dividers 1535, 1536 form a double divider structure. The voltage dividers 1535, 1536 divide the bus voltages generated by the CAN_H, CAN_L signals by reducing their level which will be processed by the comparators 151, 152.

The double divider structure of the receiver stage 150 can also verify at the same time or simultaneously two different reception thresholds among the reception thresholds T1, T2, T3, T4, independently. In addition, using the switching unit Sw1, controlled by the operating mode setting unit 1537, it is possible to switch between two reception thresholds among the reception thresholds T1, T2, T3, T4. This makes it possible to check either the reception thresholds T1, T2 according to the , independently of one another and at the same time or else the reception thresholds T1, T4 according to the , independently of each other and at the same time. Thus, depending on requirements, two of the four reception thresholds T1, T2, T3, T4 can be controlled on a third reception threshold.

The operating mode adjustment unit 1537 thus adjusts the reception thresholds T1, T2, T3, T4 according to the operating mode requested (SLOW, FAST_TX, FAST_RX) of the transmission and reception installation 12 or according to the operating mode (SIC, SLOW, FAST_TX, FAST_RX) requested by the transmission/reception installation 12.

According to a seventh embodiment of the participant station 10, in reception, the control of the network manipulation is done by using the voltage difference VDIFF. In this case, the installation 12, 22, 12A, 12B, 12C, 12D used in data phase 452 is switched to FAST_RX mode. At the end of the FAST_RX operating mode, the installation 12, 22, 12A, 12B, 12C, 12D expects from the participant station 10, 30 issuer the bit AL1 of the which indicates the end of the frame 450 in the data phase 452. The verification of the network manipulation can thus be done at the end of the bit AL1 because the verification of the reception threshold T2 (OOB function) is no longer necessary. As already indicated, the verification is carried out on the falling edge at the end of the bit AL1 in the voltage difference VDIFF, as has already been described for the previous embodiments.

Nevertheless, it is necessary, in this case, that the receiver participant station 10 contains, for each possible transmitter, that is to say for each other participant station 10, 30 of the Bus system 1, a reference value CA2_0 to judge the behavior of Bus 40 with respect to network manipulations. This also means that the receiving participant station 10 must carry out, for a number (n) of participant stations 10, 20, 30 in the Bus system 1, the verification of the network manipulations for (n-1) participant stations. By comparison, the verification with a participant station 10, transmitter, as has been described in the previous embodiments is much less complicated in time and more reduced for the calculation capacity and the memory capacity.

Overall, in order to capture network manipulations and process them or the reaction of the captured network manipulations, it is necessary that the capture and processing or the reaction for all bus systems can be applied at least partially. In particular, the following possibilities can be combined with one another.

The entry of network manipulations can thus determine for which subscriber station 10, 20, 30 of the Bus system 1, the network manipulation is checked by the evaluation of the Bus voltage signal, in particular the voltage difference VDIFF. In this case, the most advantageous solution is to check only on the transmitting participant stations 10, 20, 30 of the Bus system 1, as in embodiments 1 to 6. Alternatively, for all the receiving participant stations 10 , 20, 30 of the bus system is checked, as in the seventh embodiment. This alternative is nevertheless less advantageous because the verification must apply to a number (n-1) of participating workstations 10, 20, 30, which complicates the verification.

The input of network manipulations can be distinguished according to the number of signals of the Bus voltage to be exploited, in particular, of the comparators used for the voltage difference VDIFF; It is possible to use only the comparator which performs the verification of the reception threshold T2 (OOB). In the embodiments described above, this is then the second comparator 152. Alternatively, in addition to the receiver comparator which performs the verification of the reception threshold T2 (OOB), a reception comparator is used which uses the reception threshold typically for VDIFF=0.7V. This is the preferred solution as described for the previous embodiments. However, it is possible, even if it is more complicated, to use additional comparators in addition to the two reception comparators already mentioned.

The network manipulation operation can thus differ depending on where the output signal of at least one comparator is sent, as in the first example embodiment and the following example embodiments. According to the first example, the output signal is transmitted to the protocol controller 111. According to a second example, the output signal is transmitted only to a clock 112 which is controlled by the protocol controller 111. According to a third example, the output signal is transmitted the output signal to both protocol controller 111 and clock 112.

In addition, the detection of the moment of input and then the exploitation of network manipulations may differ, which can also be considered as the moment of evaluation of the manipulations. According to a first example, the moment of the evaluation is determined with a protocol controller 159 having reduced functionality, the protocol controller 159 equipping the transmission and reception installation 12 as in the fourth example embodiment. According to a second example, the moment of the evaluation is entered with a block 161 which enters the mode of operation of the transmission/reception installation 12 as in the fifth embodiment.

The evaluation of the network manipulations can also differ depending on whether an additional connection (Pin) of the transmission/reception installation 12 is used for the signal to be exploited. A connection (Pin) already existing in the transmission installation / reception 12 can be used in a multiplex process as described for the first embodiment.

All the realizations of the transmitter module 121, 1210, of the receiver module 122, of the installations 12, 22, 12A, 12B, 12C, 12D, of the receiver circuits 15, 150, of the participant stations 10, 20, 30 of the Bus system 1 and methods carried out according to the exemplary embodiments and their modifications can be applied separately or in all possible combinations. In addition, the following modifications can be considered.

The Bus system 1 described above according to the example embodiments has been described in the case of the CAN protocol for the Bus system. The Bus system 1 according to the exemplary embodiments can, however, alternatively apply other types of communication networks in which the signals are transmitted as differential signals. It is however advantageous, without this being a necessary condition, to have for the Bus 1 system, at least for certain durations, exclusive collision-free access of a participating station 10, 20, 30 to the Bus 40.

The Bus system 1 according to the exemplary embodiments and the modifications is in particular a CAN Bus system or a CAN-HS Bus system or a CAN-FD Bus system or even a CAN-SIC Bus system or a CAN-XL bus. The Bus 1 system can however correspond to another communication network in which the signals are transmitted in the form of differential signals and in series by the Bus 40.

Thus, the functionality of the example embodiments described above, for example, of the installation 12, 22, 12A, 12B, 12C, 12D can be used operating as a CAN bus system or a CAN-HS bus system or CAN-FD Bus system or CAN-SIC Bus system or CAN-XL Bus system.

The number and the organization of the participating stations 10, 20, 30 in the Bus system 1 according to the first and the second embodiment and their variants are arbitrary. In particular, it is possible to have the participant stations 10 or only the participant stations 30 in the Bus systems 1 of the example embodiments.

Claims (19)

Transmission/reception installation (12; 12A; 12B; 12C; 12D) of a participant station (10; 30) of a serial bus system (1) comprising:
- a first comparator (151) to exploit the signals (CAN_H, CAN_L) received from a Bus (40) of the Bus system (1) with a first reception threshold (T1; T3),
- a second comparator (152) to exploit the signals (CAN_H, CAN_L) received from the Bus (40) with a second reception threshold (T2) or a manipulation detection reception threshold (T4), the reception thresholds (T1 , T2, T4) used by the comparators (151, 152) being different and the second reception threshold (T2) is provided to determine whether the communication on the Bus (40) is in a first or a second phase of communication (451 , 452) to send a frame (450) on the Bus (40),
- a driver (1221) for driving a digital reception signal (RxD) to a communication control installation (11) of the participant station (10; 30),
- a logic circuit (1222) for transmitting an output signal (CA1) from the first comparator (151) and an output signal (CA2) from the second comparator (152) to the driver (1221) if the second reception threshold (T2) has been set in the second comparator and that the communication on the Bus (40) is in the first communication phase (451), and to transmit only the output signal (CA1) of the first comparator (151) to the driver (1221) if the manipulation detection reception threshold (T4) has been set in the second comparator (152) and
- a connection (C2) for transmitting the output signal (CA2) of the second comparator (152) to the communication control installation (11). Transmission/reception installation (12; 12A; 12B; 12C; 12D) according to claim 1,
- the input of the second comparator (152) is weakly low-pass filtered than the input of the first comparator (151) and,
- the output of the second comparator (152) is less strongly low-pass filtered than the output of the first comparator (151). Transmitting/receiving installation (12; 12A; 12B; 12C; 12D) according to Claim 1 or 2,
in which
the connection (C2) is a connection intended exclusively to supply the output signal (CA2) of the second comparator (152) to the communication control installation (11). Transmitting/receiving installation (12; 12A; 12B; 12C; 12D) according to Claim 1 or 2,
in which
the connection (C2) is a connection which operates according to a multiplex method for at least two functions of the transmission/reception installation (12; 12A; 12B; 12C; 12D). Transmitting/receiving installation (12; 12A; 12B; 12C; 12D) according to one of the preceding claims,
including
a control circuit (158) for switching the reception threshold of the second comparator (152) from the second reception threshold (T2) to the manipulation detection reception threshold (T4) for a predetermined duration in a frame (450) sent on a Bus (40) of the Bus system (1). Transmitting/receiving installation (12B) according to claim 5,
further comprising at least one protocol controller (159) for capturing a predefined time in the frame (450), at which the control circuit (158) provides control of switching the reception threshold of the second comparator (152). Transmitting/receiving installation (12D) according to one of Claims 5 or 6,
further comprising
an operating mode input block (161) for inputting into the frame (450) a predefined instant at which the control circuit (158) must control the switching of the reception threshold of the second comparator (152). Transmitting/receiving installation (12; 12A; 12B; 12C; 12D) according to one of Claims 5 to 7,
in which
the control circuit (158) carries out the switching control of the reception threshold of the second comparator (152) if the transmission/reception installation (12; 12A; 12B; 12C; 12D) is the receiver of the frame (450 ). Transmitting/receiving installation (12; 12A; 12B; 12C; 12D) according to one of the preceding claims,
further comprising a voltage divider (1533) connected to the Bus (40) to supply the signals (CAN_H, CAN_L) received from the Bus (40) to the first comparator (151,; 152) and to the second comparator (152; 151),
the first and the second comparator (151, 152) being connected to the voltage divider (1533) to simultaneously exploit the signals (CAN_H, CAN_L). Transmission/reception installation (12; 12A; 12B; 12C; 12D) according to one of Claims 1 to 8,
including
a first voltage divider (1535) to adjust the first reception threshold (T1) or a third reception threshold (T3), the first comparator (151) being connected to the first voltage divider (1535) to exploit the signals (CAN_H , CAN_L) received from the Bus (40) of the Bus system (1), with the first or third reception threshold (T1; T3) set by the first voltage divider (1535),
a second voltage divider (1536) for setting the second reception threshold (T2) or the manipulation detection reception threshold as a fourth reception threshold (T4), the second comparator (152) being connected to the second voltage divider ( 1536) to exploit the signals (CAN_H, CAN_L) received from the Bus (40) with the second or fourth reception threshold (T2; T4) set by the second voltage divider (1536) and,
the first and the second voltage divider (1535, 1536) being respectively connected to the Bus (40). Transmitting/receiving installation (12; 12A; 12B; 12C; 12D) according to claim 10,
in which
the first and the second voltage divider (1535, 1536) comprising a resistor circuit to which the first and the second comparator (151, 152) are connected and
the first and the second comparator (151, 152) simultaneously exploiting the signals (CAN_H, CAN_L). Transmitting/receiving installation (12; 12A; 12B; 12C; 12D) according to claim 10 or 11,
in which
at least one of the first and second voltage dividers (1535, 1536) has at least one switching unit (Sw1; Sw2; Sw3) for switching between the second and the fourth reception threshold (T2, T4) for the second comparator (152) depending on the mode of operation of the transmission/reception installation (12; 12A; 12B; 12C; 12D) …………………………….to switch the first or the second communication phase (451, 452) of a communication on the Bus (40). Transmitting/receiving installation (12; 12A; 12B; 12C; 12D) according to claim 12,
in which
at least one switching unit (Sw1; Sw2; Sw3) is provided to connect the voltage divider (1535; 1536) to ground or to disconnect the voltage divider (1535; 1536) from ground. Transmitting/receiving installation (12; 12A; 12B; 12C; 12D) according to one of the preceding claims,
including
at least one second comparator (152). Participant station (10; 20; 30) for a serial bus system (1) comprising:
- a transmission/reception installation (12; 12A; 12B; 12C; 12D) according to one of the preceding claims and,
- a communication control device (11; 21) for controlling the communication in the Bus system (1) and for generating a digital transmission signal (TxD) for the transmission module (121; 1210). Participant station (10; 20; 30) according to claim 15,
in which
the communication control installation (11; 21) comprises a protocol controller (111) which, in order to exploit the output signal (CA2) of the second comparator (152) is cut off from the connection (C2). Participant station (10; 20; 30) according to claim 16,
in which
the communication control installation (11; 21) comprises a clock (112) for the time control of the protocol controller (111),
- the clock (112) further exploiting the output signal (CA2) of the second comparator (152) via the connection (C2). Participant station (10; 20; 30) according to claim 11 equipped to communicate in a Bus system (1), in that at least from time to time exclusive access without collision is ensured to a participant station (10 ; 20; 30) on the bus (40) of the bus system (1). Method for detecting manipulation in a serial bus system (1),
according to which
The method is executed with a transmission/reception installation (12; 12A; 12B; 12C; 12D) of a participant station (10; 30) of a serial bus system (1),
* the transmission/reception installation (12; 12A; 12B; 12C; 12D) having a first comparator (151), a second comparator (152), a driver (1221) and a connection (C2),
the method consisting in carrying out the following steps:
- exploit with the comparator (151), the signals (CAN_H, CAN_L) received from a Bus (40) of the Bus system (1) with a first reception threshold (T1),
- exploit with the second comparator (152), the signals (CAN_H, CAN_L) received from the Bus (40) with a second reception threshold (T2) or a manipulation detection reception threshold (T4), the reception thresholds ( T1, T2, T4) used by the comparator (151, 152) being different and,
* the second reception threshold (T2) being provided to determine if the communication on the Bus (40) is in a first or a second phase of communication (451, 452) to transmit a frame (450) on the Bus (40) ,
- transmit by the logic circuit (1222), an output signal (CA1) of the first comparator (151) and an output signal (CA2) of the second comparator (152) to the driver (1221) if the second reception threshold (T2 ) is set in the second comparator (152) and if the communication by the Bus (40) is in the first communication phase (451) and,
- transmit, by the logic circuit (1222) only the output signal (CA1) of the first comparator (151) to the driver (1221) if the manipulation detection reception threshold (T4) is set in the second comparator (152) And,
- driving with the pilot (1221) a digital reception signal (RxD) to a communication control installation (11) of the participant station (10; 30), and
- Transmit via the connection (C2) the output signal (CA2) of the second comparator (152) to the communication control installation (11).