FR3145661A1 - Method and device for determining a type of data bus used for transmitting signals between peripherals in a vehicle - Google Patents

Abstract

The invention relates to a method for determining a type of data bus used for transmitting signals between peripherals in a vehicle, said method comprising the following steps: a) receiving (21) a signal transmitted on said data bus; b) extracting (22) a first identifier from said received signal; c) if said first identifier corresponds to a second stored identifier (23), then the type of data bus is determined (24) as being a data bus of a first type; otherwise steps a), b) and c) are iterated until a stop condition is verified (25); if the stop condition is verified (25), the type of data bus is determined (26) as being a data bus of a second type belonging to a set of at least one type of data bus. Abstract: Figure 3

Description

Method and device for determining a type of data bus used for transmitting signals between peripherals in a vehicle

The invention relates to methods and devices for determining a type of data bus of a vehicle, in particular of the automobile type. The invention also relates more particularly to a method and a device for adapting a peripheral connected to a data bus of a vehicle.

Technological background

Contemporary vehicles have a number of peripherals incorporating computers, each of which performs one or more functions, such as, for example, the management of driving assistance, anti-skid, electronic brake distribution, the control of actuators to ensure the optimal operation of a combustion engine or the management of a human-machine interface (HMI).

These computers are connected to each other via a multiplexed serial data bus of the CAN type (from the English "Controller Area Network" or in French "Network of controllers"). CAN data buses exist in different versions, such as the CAN LS bus (from the English "Low Speed", in French "Faible vitesse", the maximum flow rate being approximately 125Kbit/s), the CAN HS bus (from the English "High Speed", in French "Grande vitesse", the maximum flow rate being approximately 1Mbit/s), the CAN FD bus (from the English "Flexible Data-Rate", in French "Débit de données Flexible").

The coding of the signals that pass through it is therefore different depending on the version of the CAN bus. Thus, a device integrating a calculator developed to be installed on a certain version of the CAN bus cannot be installed on a second version of the CAN bus, since the calculators are not compatible with several versions of the CAN bus.

The data bus and calculators together form the vehicle's on-board system. These calculators are also called ECUs ("Electronic Control Units"). These calculators carry software that is executed to perform the functions for which they are responsible.

A computer is installed in a specific device, depending on the type of data bus used for transmitting signals between devices in a vehicle. Such a computer is therefore not compatible with all data buses used in several vehicles.

When configuring the vehicle at the factory, it is then necessary to know the different computers that can equip a vehicle and their compatibility with the different versions of data bus installed in the vehicle in order to be able to configure these different computers.

An object of the invention is to solve at least one of the problems of the prior art, for example to determine the type of a data bus used for the transmission of signals between peripherals in a vehicle.

According to a first aspect, the invention relates to a method for determining a type of data bus used for the transmission of signals between peripherals in a vehicle, the method being implemented by at least one processor on board the vehicle, the method comprising the following steps:
a) reception of a signal transmitted on the data bus;
b) extracting a first identifier from the received signal;
(c) if the first identifier matches a stored second identifier, then the data bus type is determined to be a data bus of a first type;
otherwise steps a), b) and c) are iterated until a stopping condition is met;
if the stop condition is verified, the data bus type is determined to be a data bus of a second type belonging to a set of at least one data bus type.

The method allows the device implementing it to determine the type of data bus to which it is connected. The device thus adapts its communication interface to the data bus to which it is connected and can then communicate with the other peripherals connected to this same data bus. The configuration or update, in particular software, in the factory or in an after-sales service of this device is therefore facilitated compared to the configuration of a device which would not implement this method.

According to a variant of the method, a stopping condition is verified when a predetermined number of signals is received.

According to another variant of the method, a stopping condition is verified when a time interval has elapsed since receipt of a first signal.

These stopping conditions thus prevent the process from being followed indefinitely.

According to a variant of the method, the first and second identifiers correspond to an address of a device.

According to a variant of the method, the first identifier is coded on 11 bits.

According to a variant of the method the data bus is a serial data bus.

According to a variant of the method the data bus is a CAN data bus.

According to a second aspect, the invention relates to a device configured to determine a type of a data bus of a vehicle, the device comprising a memory associated with at least one processor configured to implement the steps of the method according to the first aspect of the invention.

According to a third aspect, the invention relates to a data bus comprising the device as described above according to the second aspect of the invention and one or more computers.

According to a fourth aspect, the invention relates to a vehicle, for example of the automobile type, comprising a device as described above according to the second aspect of the invention or a data bus as described above according to the third aspect of the invention.

According to a fifth aspect, the invention relates to a computer program which comprises instructions adapted for executing the steps of the method according to the first aspect of the invention, in particular when the computer program is executed by at least one processor.

Such a computer program may use any programming language, and may be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other desirable form.

According to a sixth aspect, the invention relates to a computer-readable recording medium on which is recorded a computer program comprising instructions for carrying out the steps of the method according to the first aspect of the invention.

On the one hand, the recording medium may be any entity or device capable of storing the program. For example, the medium may include a storage medium, such as a ROM memory, a CD-ROM or a microelectronic circuit type ROM memory, or a magnetic recording medium or a hard disk.

On the other hand, this recording medium may also be a transmissible medium such as an electrical or optical signal, such a signal being able to be conveyed via an electrical or optical cable, by conventional or terrestrial radio or by self-directed laser beam or by other means. The computer program according to the invention may in particular be downloaded from a network such as the Internet.

Alternatively, the recording medium may be an integrated circuit in which the computer program is incorporated, the integrated circuit being adapted to perform or to be used in performing the method in question.

Brief description of the figures

Other characteristics and advantages of the invention will emerge from the description of the non-limiting embodiments of the invention below, with reference to the appended figures 1 to 4, in which:

schematically illustrates a data bus of a vehicle, according to a particular and non-limiting exemplary embodiment of the invention;

schematically illustrates a frame of a signal transmitted on the data bus of the , according to a particular and non-limiting exemplary embodiment of the invention;

illustrates a flowchart of the different steps of a method for determining a data bus type of the , according to a particular and non-limiting exemplary embodiment of the invention;

schematically illustrates a device configured to determine a data bus type of the , according to a particular and non-limiting exemplary embodiment of the invention;

A method and device for determining a data bus type will now be described in the following with joint reference to Figures 1 to 4. The same elements are identified with the same reference signs throughout the description which follows.

According to a particular and non-limiting example of embodiment of the invention, a signal transmitted on a serial data bus, for example of the CAN LS, CAN HS or CAN FD type of a vehicle is received by a device connected to this data bus, for example a computer of an on-board system of the vehicle connected to other computers of the on-board system via the data bus. The device extracts a first identifier from the received signal. The first identifier identifies a message carried by the first signal. The first identifier is for example coded on 11 bits. The device compares the first identifier to a second identifier stored in the memory of the device. The second identifier advantageously characterizes a first type of data bus. The result of the comparison thus allows the device to detect whether the data bus is of the first type of data bus.

Such a method has the advantage of being simple to implement by requiring only the storage in memory of an identifier characteristic of an identifier transmitted on the data bus of the first type. Thus, no learning phase is necessary to implement the method. The resources in terms of calculation and memory footprint necessary for the implementation of this method are low. The hardware architecture of a standard calculator of an on-board system of a vehicle is adapted to such an implementation.

Such a method is for example suitable for determining a type of serial data bus, for example of type CAN HS, CAN LS or CAN FD.

The device then adapts its communication interface to the type of data bus determined and to which it is connected.

There schematically illustrates a data bus 100 of a vehicle, according to a first particular and non-limiting exemplary embodiment of the invention.

The data bus 100 advantageously corresponds to a multiplexed type data bus connecting several computers 11, 12 and 13. A device 10 configured to determine the type of data bus 100 is also connected to the computers 11 to 13 via the data bus 100. Such a device corresponds for example to a device configured to receive and process data and is for example hosted in a computer in the form of a software module.

The assembly formed by the data bus 100, the computers 11 to 13 and the device 10 form all or part of an on-board system of the vehicle, for example a motor vehicle. The number of computers 11 to 13 is however not limited to 3 and extends to any number, for example 2, 5, 10, 100 or more computers.

The on-board system also comprises, for example, a telematic control unit, called TCU (from the English “Telematic Control Unit”), connected in communication with the computers 11 to 13 via the data bus 100. The TCU is connected to one or more antennas of the vehicle for the communication of data between the vehicle and one or more remote devices, for example via a wireless link based on a cellular network of the LTE type (from the English “Long-Term Evolution” or in French “Evolution à long terme”), LTE-Advanced (or in French LTE-advanced), also called 4G or 5G network.

The data bus is a serial bus, for example of the CAN LS type as defined in the ISO 11898-2 standard, of the CAN HS type as defined in the ISO 11898-3 standard or of the CAN FD type as defined in the ISO 11898-1 standard. The data bus 100 advantageously implements time multiplexing allowing the computers 11 to 13 to transmit signals (also called signal frames) in turn. The signals transmitted may be of several types depending on the data that they transport, each type of signal being identified by a specific and particular identifier. As will be described in more detail with regard to the , the signals transmitted on the data bus 100 are identified via an identifier whose value is known, this value being for example coded on a determined number of bits, for example 11 bits.

The signals have, for example, an event-related nature and are then of a specific type identified by a specific and unique identifier. The signals are said to be event-related in that they are transmitted when an event is detected at the level of a computer, for example the computer 11, or of a sensor associated with a computer for example. The event-related signals are transmitted at irregular intervals which depend on the occurrence of the events to be reported. For example, two consecutive event-related signals can be transmitted with a time interval of 30 ms and the two following consecutive event-related signals can be transmitted on the data bus 100 with a time interval between these signals equal to 10 minutes. An event corresponds, for example, to an alert, for example associated with a threshold being exceeded (rotation speed of the engine shaft greater than a threshold, engine temperature greater than a threshold, etc.).

According to another example, the signals have a periodic character. These periodic signals are of a specific type identified by a specific and unique identifier. The signals are said to be periodic in that they are transmitted at regular intervals (a period) by a computer, for example every 10, 20, 30 ms.

According to an alternative embodiment, the data bus 100 corresponds for example to a FlexRay type bus (according to the ISO 17458 standard) or Ethernet (according to the ISO/IEC 802-3 standard).

There schematically illustrates a frame 3 of a signal transmitted on the data bus 100 by a computer of the on-board system of a vehicle, according to a particular and non-limiting exemplary embodiment of the invention.

According to the illustrative example of the , only a part of the fields of frame 3 of the transmitted signal are described or represented, in particular those relating to the subject of the invention.

• un premier champ 31 correspondant à un début de trame, dit SOF (de l’anglais « Start Of Frame »), comprenant par exemple 1 bit ;
• un deuxième champ 32 correspondant par exemple à un champ d’arbitrage, aussi appelé champ identificateur, et comprenant l’identifiant du message porté par le signal transmis sur 11 ou 29 bits suivi d’un bit RTR (de l’anglais « Remote Transmission Request », en français « demande de télétransmission »). Ce champ comprend par exemple 12 ou 32 bits ; ce champ sert avantageusement d’identifiant pour les données ou types de données transportées par le signal transmis, c’est-à-dire dans la partie appelée champ de données ;
• des troisièmes champs 33 à 36 formant un champ de données et comprenant notamment un compteur et des données utiles du message porté par le signal transmis ; ces champs 33 à 36 comprennent par exemple chacun 8 bits ; le compteur du message est par exemple compris dans le premier de ces champs, c’est-à-dire le champ 33, et les données utiles dans les autres champs, c’est-à-dire les champs 34, 35 et 36 ; selon un autre exemple, le compteur est compris dans le dernier de ces champs, c’est-à-dire le champ 36 ; selon une variante, il y a plus de 4 champs de données, par exemple 8 champs de données ;
• un quatrième champ 37 correspondant à une fin de trame, dit EOF (de l’anglais « End Of Frame »), comprenant par exemple 7 bits.

Frame 3 of the transmitted signal thus includes:

• a first field 31 corresponding to the start of a frame, called SOF (from the English “Start Of Frame”), comprising for example 1 bit;
• a second field 32 corresponding for example to an arbitration field, also called an identifier field, and comprising the identifier of the message carried by the transmitted signal on 11 or 29 bits followed by an RTR bit (from the English “Remote Transmission Request”). This field comprises for example 12 or 32 bits; this field advantageously serves as an identifier for the data or types of data transported by the transmitted signal, that is to say in the part called the data field;
• third fields 33 to 36 forming a data field and comprising in particular a counter and useful data of the message carried by the transmitted signal; these fields 33 to 36 each comprise, for example, 8 bits; the message counter is, for example, included in the first of these fields, i.e. field 33, and the useful data in the other fields, i.e. fields 34, 35 and 36; according to another example, the counter is included in the last of these fields, i.e. field 36; according to a variant, there are more than 4 data fields, for example 8 data fields;
• a fourth field 37 corresponding to the end of a frame, called EOF (from the English “End Of Frame”), comprising for example 7 bits.

Frame 3 of the transmitted signal also possibly includes other fields not described or not shown in the , such as for example a control field (for example on 6 bits), a CRC field (from the English “Cyclic Redundancy Check” or in French “Cyclic redundancy check”) and/or an acknowledgment field.

There illustrates a flowchart of the different steps of a method for determining a type of data bus 100 of the , according to a first particular and non-limiting example of embodiment of the invention.

Such a method is advantageously implemented by the device 10 connected or linked to the data bus 100. The steps of the method below will be described with reference to the reception and processing of a signal. Of course, the same operations apply to the reception and processing of several signals in a manner identical to that described by taking a signal as an example.

In a first step 21, a signal transmitted on the data bus 100 is received by the device 10. The signal (or the frame of the signal) is for example transmitted on the data bus by one of the computers 11 to 13. The structure of the signal corresponds to the frame 3 described previously.

In a second step 22, the device 10 extracts (retrieves or determines) the identifier of the received signal, called the first identifier.

The first identifier is for example obtained from the arbitration field 32 of the signal.

According to a variant of step 22, the first identifier corresponds to a binary code.

According to an exemplary embodiment of this variant, the first identifier corresponds to a binary string for example of length equal to 11 bits, each bit of the string taking the value 0 or 1.

According to another exemplary embodiment of this variant, the first identifier corresponds to a string of length equal to 29 bits, each bit of the string taking the value 0 or 1.

In a third step 23, the first identifier is compared to at least one second identifier stored in a memory.

According to a variant of step 23, the memory is a memory of the device 10.

According to another variant of step 23, the memory is a memory of a device other than the device 10 (for example a memory of one of the computers 11 to 13) accessible by the device 10, for example via the data bus 100.

According to an exemplary embodiment of step 23, the at least one second identifier is advantageously stored in a table.

The at least one second identifier corresponds to an identifier of a signal whose type is known to the device 10, this type of signal circulating specifically on a type of data bus 100.

According to an exemplary embodiment of step 23, the first and second identifiers advantageously correspond to an address of a peripheral present only on a certain type of data bus.

When the first identifier matches the second identifier, then the data bus 100 is determined in a step 24 as being of a first type of data bus.

When the result of the comparison indicates that the first identifier does not match any second identifier, a stopping condition is checked (step 25).

If the stop condition is not met then the device waits for the reception of a new frame of a signal to repeat steps 21 to 23.

If the stop condition is met, the data bus 100 is determined in a step 26 as being of a second type of data bus belonging to a set of at least one type of data bus.

According to an exemplary embodiment of step 25, a stop condition is met when a predetermined number of signals are received.

According to an exemplary embodiment of step 25, a stop condition is met when a time interval has elapsed since a reception of a first signal.

Once the data bus type 100 has been determined, the device adapts, for example, its communication interface to the determined bus type.

According to an exemplary embodiment, a device is connected to a serial data bus of a vehicle equipped with either a CAN HS bus or a CAN FD bus. The second identifier corresponds to the address of a calculator characteristic of a CAN HS bus, its coded address corresponds to E9 in hexadecimal code, or 11101001 in binary code. The device determines the type of bus to which it is connected by following the method previously described in relation to the The first identifier contained in the different frames received by the device via the serial data bus is then compared to the second predetermined identifier.

If a first identifier from a received frame matches the coded address of a CAN HS bus characteristic calculator, then the device determines the serial data bus type as being of the CAN HS type.

If, conversely, after a few hundred milliseconds, no first identifier from several frames received corresponds to the coded address of a calculator characteristic of a CAN HS bus, then the device determines by elimination the type of serial data bus as being of the CAN FD type.

The device thus adapts its communication interface to the data bus to which it is connected and can then communicate with other peripherals connected to the same data bus.

According to a variant of the method, when a stop condition is met, then a new second identifier corresponding to a second type of data bus or a new table of second identifiers is defined and steps 21 to 23 are repeated with these new second identifiers. Thus, a first type of bus is eliminated and the process makes it possible to search for a second type of data bus among a set of data bus types.

There schematically illustrates a device 4 configured to determine a type of a data bus 100, according to a particular and non-limiting exemplary embodiment of the invention. The device 4 corresponds for example to the device 10.

The device 4 is for example configured for the implementation of the steps of the method described with regard to the . The elements of the device 4, individually or in combination, can be integrated into a single integrated circuit, into several integrated circuits, and/or into discrete components. The device 4 can be produced in the form of electronic circuits or software (or computer) modules or even a combination of electronic circuits and software modules. According to various particular embodiments, the device 4 is coupled in communication with other similar devices or systems, for example via a communication bus or through dedicated input/output ports.

The device 4 comprises one (or more) processor(s) 40 configured to execute instructions for carrying out the steps of the method and/or for executing the instructions of the software(s) embedded in the device 4. The processor 40 may include integrated memory, an input/output interface, and various circuits known to those skilled in the art. The device 4 further comprises at least one memory 41 corresponding for example to a volatile and/or non-volatile memory and/or comprises a memory storage device which may comprise volatile and/or non-volatile memory, such as EEPROM, ROM, PROM, RAM, DRAM, SRAM, flash, magnetic or optical disk.

The computer code of the embedded software(s) comprising the instructions to be loaded and executed by the processor is for example stored in the first memory 41.

According to a particular embodiment, the device 4 comprises a communication interface 43 which makes it possible to establish communication with other devices (such as the computers of the on-board system and connected to the data bus) via a communication channel 430. The communication interface 43 corresponds for example to a transmitter configured to transmit and receive information and/or data via the communication channel 430. The communication interface 43 corresponds for example to a wired network of the CAN LS, CAN FS or CAN FD type.

According to an additional particular embodiment, the device 4 can provide output signals to one or more external devices, such as a display screen, one or more speakers and/or other peripherals via respectively output interfaces not shown.

Of course, the invention is not limited to the embodiments described above but extends to a method for determining a type of data bus used for the transmission of signals between peripherals in a vehicle and to the device configured for the implementation of the method.

The invention also relates to a vehicle, for example an automobile or more generally a land motor vehicle, comprising the device 4 of the or the 100 data bus of the .

Claims (10)

Method for determining a type of data bus used for the transmission of signals between peripherals in a vehicle, said method being implemented by at least one processor embedded in said vehicle, said method comprising the following steps:
a) receiving (21) a signal transmitted on said data bus (100);
b) extracting (22) a first identifier from said received signal;
c) if said first identifier corresponds to a second stored identifier (23), then the data bus type is determined (24) as being a data bus of a first type;
otherwise steps a), b) and c) are iterated until a stopping condition is verified (25);
if the stop condition is verified (25), the data bus type is determined (26) as being a data bus of a second type belonging to a set of at least one data bus type. The method of claim 1, wherein a stop condition is met when a predetermined number of signals are received. Method according to one of claims 1 to 2, for which a stop condition is verified when a time interval has elapsed since a reception of a first signal. Method according to one of claims 1 to 3, for which the first and second identifiers correspond to an address of a peripheral. Method according to one of claims 1 to 4, for which said first identifier is coded on 11 bits. Method according to one of the preceding claims, wherein the data bus is a serial data bus. The method of claim 6, wherein said data bus (100) is a CAN data bus. Device (4) configured to determine a type of a data bus (100) of a vehicle, said device (4) comprising a memory (41) associated with at least one processor (40) configured to implement the steps of the method according to any one of claims 1 to 7. Vehicle comprising the device (4) according to claim 8. Computer program comprising instructions for implementing the method according to one of claims 1 to 7, when these instructions are executed by a processor.