Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F13/00—Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
  • G06F13/38—Information transfer, e.g. on bus
  • G06F13/40—Bus structure
  • G06F13/4063—Device-to-bus coupling
  • G06F13/4068—Electrical coupling
  • G06F13/4086—Bus impedance matching, e.g. termination
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L25/00—Baseband systems
  • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
  • H04L25/0264—Arrangements for coupling to transmission lines
  • H04L25/0278—Arrangements for impedance matching
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L25/00—Baseband systems
  • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
  • H04L25/0264—Arrangements for coupling to transmission lines
  • H04L25/0298—Arrangement for terminating transmission lines

Definitions

• the invention relates to an electronic control unit with line termination, as well as to a digital communication network comprising such an electronic control unit, allowing electrical equipment or subassemblies of electrical equipment, to communicate between them, with a reduced number of electrical wires.
• Such communications networks are used, for example, for applications in the field of automobiles, industrial installations, railways, the military or even consumer electronics.
• Some digital communication networks have line terminations designed to match the impedance of the network and comply with network topology rules.
• the CAN HS communication network comprises two line terminations generally located on the furthest nodes of the network.
• FIG. 1 represents an exemplary topology of such a network.
• the bus line 10 interconnects several electronic control units ECU_A, ECU_B, ECU_C and ECU_D, two of which, ECU_A and ECU_B, are equipped with T line terminations, it being understood that said bus line can be composed of 1 wire or more.
• FIG. 2 represents an electronic control unit 20 (ECU) with line termination, in the nonlimiting example of a 2-wire bus line.
• a unit comprises a computer 22 ( ⁇ ), for example a microcontroller, and a line termination 24 defined by a termination circuit, R T A, RTB and CT, connected between the signal transmission wires CAN_H and CAN_L forming the bus line 10.
• Each termination can thus, for example, be integrated into a control unit present on the vehicle network.
• FIG. 3 represents a first example of application on a vehicle 30 comprising a communication network 32 with three electronic control units 34, 36 and 38, for example a Multifunction Motor Calculator (MMC), a Programmed Electro-Stabilizer (ESP) and an Intelligent Service Enclosure (BSI).
• MMC Multifunction Motor Calculator
• ESP Programmed Electro-Stabilizer
• BSI Intelligent Service Enclosure
• FIG. 4 represents a second example of application on a vehicle 40 comprising a communication network 42 with four electronic control units 44, 46, 48 and 49.
• ESP and BSI units shown in FIG. network also includes a fourth Electric Parking Brake unit (ESF) generally arranged at the rear end of the vehicle.
• ESF Electric Parking Brake unit
• the line termination T integrated in the BSI unit in the example of Figure 3 can be advantageously moved in the FSE unit.
• the first solution is to manage diversity on the BSI unit, creating two variants with and without line termination.
• This first solution has the disadvantage of doubling the diversity of the BSI units compared to the existing diversity related to other factors, resulting in an additional cost in the management of diversity, the number of references at the edge of the assembly line and in spare parts.
• the second solution consists in managing the diversity by the use of a network configurable line termination electronic control unit 50, that is to say by integrating the termination components of the network. line 54 to the BSI unit and planning to connect them to CAN_H and CAN_L transmission wires not internally of the control unit 50 but via two additional pins 56a and 56b and a "bridge" 58 made by two additional wires.
• This second solution has the disadvantage of requiring the addition of two pins in the connection of the BSI unit, and the addition of a two-wire "bridge” in the wiring on the vehicles without FSE unit, generating extra cost due to the additional pins and wires.
• an electronic bus system for fixed or mobile applications, such as a CAN bus system for use in the automotive industry.
• the bus system comprises a bus line with at least two signal transmission wires and two ends, each being defined by a terminating resistor connecting the signal transmission wires to each other, and a plurality of electronic control units, which between the two ends are connected to the signal transmission wires and are adapted to transmit and receive electrical signals via the signal transmission wires.
• the line is divided into a plurality of sections, which are interconnected by means of connection circuits and form an annular unit.
• Each connection circuit comprises relay means by means of which each connection circuit is adapted, in coordination with the other connection circuits, for connecting at least one of the electronic control units to the signal transmission wires and / or for connecting to the least one terminating resistor to the signal transmission wires to define the ends of the bus line.
• Such an annular topology electronic bus system makes it possible to disconnect a defective section of the annular unit and to redefine the new ends excluding the defective section by switching the termination resistors of the remaining sections according to the modified topology of the bus line.
• Such a system does not, however, adapt to different configuration of the bus line depending on the presence or absence of some electronic control units.
• such a system requires the use of a plurality of electronic control units provided with connecting circuit means communicating with each other to detect the malfunction or otherwise of a control unit. neighboring electronics. Such a solution is therefore restrictive in its applications and expensive in its implementation.
• the invention aims to overcome the drawbacks of the state of the art and in particular to provide a configurable line termination electronic control unit capable of adapting to different configurations of a digital communication network.
• a configurable line termination electronic control unit for digital communication network to at least one transmission line formed of two signal transmission wires, said electronic control comprising a line termination essentially defined by an equivalent terminating resistor capable of connecting the signal transmission wires to each other, and characterized in that the electronic control unit further comprises a line termination switching device for enable line termination.
• Such an electronic control unit allows the switching of the line termination if necessary. Thus, if the communication network includes the correct line terminations, the electronic control unit will command not to activate its termination, whereas if the communication network still requires line termination then the electronic control unit will control the termination of the line. activation of its termination.
• the control unit may be connected to a diagnostic tool, such as another digital communication network or a diagnostic line, so as to telecode the control unit by example according to the nomenclature of the vehicle.
• a diagnostic tool such as another digital communication network or a diagnostic line
• the electronic control unit further comprises a device for determining the presence of other line terminations on the communication and self-adaptation network to control the activation of the line termination. depending on the presence or absence of other line terminations on the communication network.
• a device for determining the presence of other line terminations on the communication and self-adaptation network to control the activation of the line termination. depending on the presence or absence of other line terminations on the communication network.
• the electronic control unit will command not to activate its termination, whereas if the communication network still requires line termination then the electronic control unit will control the termination of the line. activation of its termination.
• Such an electronic control unit by virtue of its self-adaptation function, makes it possible to dispense with a configuration of telecoding switching requiring another communication network to communicate with the unit.
• the device for determining the presence of other line terminations is a device for measuring a polarization magnitude of the communication network comprising two sources of a reference polarization magnitude, two bias for respectively connecting a source of a reference bias magnitude to the equipotential of the line termination and the other source of a reference bias magnitude to a signal transmission wire for biasing the communication network with adequate voltages, and means for measuring the polarization magnitude of the communication network to determine the situation in terms of line termination.
• a configurable line termination electronic control unit can thus measure a magnitude such as the bias voltage of the communication network to determine the network situation in terms of line termination present on the network.
• the measurement of the bias voltage is performed via an analog input of a calculation unit of the control unit.
• Such a measure is simple and inexpensive to implement.
• the configurable line termination electronic control unit further comprises a power source, and a power switch adapted to control the power supply of the other electronic control units of the communication network.
• a power device makes it possible to measure a magnitude of the communication network without mutual disturbance with the other electronic control units if they were fed during the measurement phase.
• the switching device comprises a first terminating switch located between a transmission wire and a first line terminating resistor, and a second terminating switch located between the other transmission wire and the resistor. line termination, and a calculation unit programmed to control the termination switches.
• the switching device further comprises a logic flip-flop between the computation unit and the termination switches. This makes it possible to mitigate a possible failure of the control unit during a critical phase such as the rolling of the vehicle in which it would be integrated and maintain a correct polarization of the network allowing the other control units to continue exchanging data. In the vehicle standby phases, the terminating switches will preferably be uncontrolled to reduce power consumption of the control unit.
• the present invention relates to a digital communication network comprising at least two signal transmission wires, a plurality of electronic control units. connected to the signal transmission wires and adapted to transmit and receive electrical signals via said signal transmission wires, at least two line termination electronic control units of said plurality of electronic control units, each line termination being essentially defined by an equivalent terminating resistor connecting the signal transmission wires to each other, and of which at least one electronic control unit is a configurable line termination electronic control unit according to the first aspect of the invention.
• a communication network makes it possible to self-adapt the configurable line termination electronic control unit according to the termination situation of the network, such as the number of non-configurable line terminations present on the network.
• the configurable line termination control unit should detect the presence or absence in the rest of the network.
• the digital communication network comprises at least one non-configurable line termination electronic control unit, and a single configurable line termination electronic control unit.
• the invention relates to a method of configuring the line terminations of a digital communication network equipped with at least one configurable line termination electronic control unit, the method comprising the steps of: ) determine the presence or absence of other line terminations in the communication network; (ii) self-adapting the impedance of the communication network by controlling the activation of the configurable line termination according to the presence or not of other line terminations.
• the determination step consists of: (it) cutting the power supplies of the other units of electronic control of the network, (i2) closing the termination switches, and the polarization switches, (i3) measuring the magnitude of polarization and deriving the network situation in terms of termination, and the self-adaptation step consists in : (ii1) controlling the activation or not of the termination switches according to said situation.
• FIG. 1 represents an exemplary topology of a communication network according to the prior art
• FIG. 2 represents a line-termination electronic control unit according to a first prior art
• FIG. 3 represents a first application of a communication network in an automobile according to the prior art
• FIG. 4 represents a second application of a communication network in an automobile according to the prior art
• - Figure 5 shows a line termination control unit according to a second prior art
• - Figure 6 shows a communication network according to an embodiment of the present invention.
• the communication network comprises at least one transmission line formed by two signal transmission wires L H and L L and a plurality of electronic control units ECUAUTO, ECUT-I, ECUT2, ECUs connected to the signal transmission wires.
• the network comprises an ECUAUTO configurable line termination electronic control unit, two control units electronic ECUn and ECUT2 non-configurable line termination according to two modes of implementation and a plurality of electronic control units ECUs without line termination.
• a first ECUn implementation consists in connecting in addition to a calculation unit ⁇ - ⁇ , two RT-IA and RT-I B resistors in series and a CTi capacitor between the equipotential between said two resistors in series and a reference potential.
• a second implementation ECUT2 consists in connecting a simple resistor RT 2 between the two transmission wires L L and L H.
• the ECUAUTO electronic control unit with configurable line termination comprises a computing unit ⁇ C which can be for example a microprocessor, a microcontroller, or any other equivalent device.
• This computing unit ⁇ C comprises a protocol manager of the multiplexed network as well as inputs / outputs for controlling the state of the network.
• the ECUAUTO control unit comprises a switch SWALIM controlled by an output of the calculation unit ⁇ , possibly via a logic latch BL1, thus allowing the ECUAUTO control unit to control the power supply of the other ECUn control units, ECUT2, ECUS of the network, and compensate for a possible failure of the ECUAUTO control unit during a rolling phase.
• the switch SWALIM is preferably not controlled in order to reduce the consumption of the ECUAUTO control unit.
• the ECUAUTO control unit further comprises a non-volatile memory MNV and a transmitter / receiver. Multiplexed trunk E / R including in particular a data TX port to be transmitted and an RX port of received data.
• the switchable line termination of the network consists of the resistors RT A and RT B and the optional capacity CT.
• a switching device makes it possible to activate or not the line termination of the network.
• This switching device is formed for example by two switches SW H and SW L respectively connected to the transmission lines L H and L L and controlled by the calculation unit possibly via a flip-flop BL2.
• the switching device for enabling or not the line termination of the network is then formed for example by a single switch SW H or SW L connected respectively to one of the transmission son L H or L L and controlled by the calculation unit possibly via a flip-flop BL2.
• the control unit ECUAUTO further comprises a device for determining the presence of other line terminations on the network and self-adaptation to control the activation or not of its line termination according to the presence or not other line terminations.
• This determination and self-adaptation device comprises two polarization switches SW PO L_H and SW PO L_L controlled by the calculation unit possibly via a flip-flop BL3, to polarize the network, as well as two biasing voltages of reference V ref. i and V ref2 .
• the flip-flop BL3 makes it possible to alleviate a possible failure of the control unit ECU AUTO during a rolling phase and to maintain a correct polarization of the network allowing the other control units ECU-pi, ECUT2, ECUS to continue exchanging data.
• the switches SW PO L_H and SW PO L_L are preferably not controlled in order to reduce the consumption of the ECUAUTO control unit.
• the voltage V ref2 can be directly connected to ground.
• the analog input V PO L of the calculation unit ⁇ C makes it possible to measure the bias voltage of the network for determining the network situation in terms of line termination of the network.
• the switching device of the line termination consists of a first switch SW H located between the line L H and the line termination resistor RTA, of a second switch SW L located between the line L L and the line termination resistor RTB and a command of the switches SW H and SW L by the calculation unit ⁇ C programmed for this purpose.
• the SW H and SW L switches are controlled by the calculation unit ⁇ C as a function of the configuration with or without line termination required by the vehicle configuration, that is to say according to the presence or not of the good number line terminations.
• This command is carried out on the basis of a measurement of the polarization situation of the network by an integrated measuring device V PO L in the computing unit ⁇ C.
• V PO L integrated measuring device
• the switches SW H and SW L will preferably be uncontrolled in order to reduce the consumption of the control unit ECUAUTO-
• the determination and self-adaptation device comprises a means for measuring a magnitude, for example a voltage V PO L, of polarization of the communication network which makes it possible to detect the situation of the network in terms of termination, as for example, whether or not the network has the right number of line terminations, and thus to perform a self-adaptation function.
• the device for measuring a bias voltage comprises two sources of reference bias voltage V ref i and V ref2 , the second V ref2 being the ground.
• the measuring device also comprises a first bias switch SW PO L_H for forcing the reference bias voltage V ref i the equipotential between the resistors RTA and RTB, and a second polarization switch SW PO L_L to force the line L L at the reference bias voltage V ref2 .
• the polarization switches SW PO L_H and SW PO L_L are preferably controlled by the calculation unit ⁇ .
• the measurement of the bias voltage V PO L is performed via an analog input of the calculation unit ⁇ connected to the line L H.
• a switching device of the power supplies (VALIM; SWALIM) of the other electronic control units ECU-pi, ECUT2, ECUS of the network allowing a measurement of the polarization of the network in the absence is also provided.
• the calculation unit ⁇ C is programmed to determine the polarization situation of the network, so that the device for measuring a bias voltage can advantageously cut off the power supplies of the other electronic control units ECU-pi, ECUT2, ECU of the network, close the switches SW H , SW L , SW PO L_H and SW PO L_L, and measure the voltage V PO L whose value makes it possible to deduce the situation of the network in terms of termination, ie the number of other units electronic controllers with line terminations, as explained below.
• two examples of line terminations are shown, with or without a "common mode" CT capacitor in the middle point.
• Vpo L V Ref1 * RT 1 / (RT A + RT 1 )
• VPOL V REF1 * (RT-i // RT 2 ) / (RT A + (RT-i // RT 2 )) ,.
• the voltage difference obtained according to the number of line terminations present enables the ECUAUTO configurable line termination electronic control unit to determine the number of these line terminations and to decide whether or not to switch the activation of its termination. line as needed to self-adapt to the communication network.

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• Computer Hardware Design (AREA)
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• 2012
  • 2012-05-02 FR FR1254023A patent/FR2990311B1/fr not_active Expired - Fee Related
• 2013
  • 2013-04-25 WO PCT/FR2013/050927 patent/WO2013164533A1/fr active Application Filing
  • 2013-04-25 CN CN201380023201.7A patent/CN104380675B/zh not_active Expired - Fee Related
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