FR3050087A1 - DEVICE AND METHOD FOR SELECTIVE SIGNAL COMMUNICATION - Google Patents

Abstract

Device for selective communication of signals embedded in a motor vehicle, comprising: - a plurality of transmitters (T1, T2, T3) each comprising an output arranged to transmit a digitized signal, - a receiver (R) connected to the outputs for receiving the signal digitized of each of said transmitters (T1, T2, T3), characterized in that: - the receiver (R) comprises a single acquisition path (VA) arranged to receive the digitized signal of each of said transmitters (T1, T2 , T3), - each of said transmitters (T1, T2, T3) comprises a switch arranged between its output and said acquisition channel (VA), - the receiver (R) comprises a control output connected to a control line ( LC) connected to said switches, for controlling each of said switches, so that only one of the outputs is connected to said acquisition path (VA) at the same time.

Description

DEVICE AND METHOD FOR SELECTIVE COMMUNICATION

OF SIGNALS

The present invention generally relates to a device and a method of selective communication of embedded signals in a motor vehicle. In particular, the invention relates to a device comprising transmitters responsible for measuring motor parameters (temperature, pressure, ...) of a motor vehicle, and comprising a receiver arranged to receive the measurement of these parameters via unidirectional lines. from the transmitters, the device being organized to transmit the measurements in the form of digital signals defined according to a SAE J2716 standard, otherwise called "SENT" protocol. The invention also relates to the method of communication between the transmitters and the receiver.

WO2015126539 discloses an architecture comprising measurement units arranged to create a digital signal from the measurements made, and a digital signal receiving unit, but this document does not propose any solution to simplify a system with lines unidirectional communications, the main feature of a system operating under SAE J2716.

An object of the present invention is to meet the disadvantages of the documents of the prior art mentioned above and in particular, first, to provide a device comprising transmitters arranged to send digital signals to a receiver via unidirectional lines, which remains simple in its architecture, and a communication method for such a device.

For this a first aspect of the invention relates to a signal communication device embedded in a motor vehicle, comprising: - a plurality of transmitters each comprising an output arranged to transmit a digitized signal, - a receiver connected to the outputs to receive the digitized signal of each of said transmitters.

And furthermore: the receiver comprises a single acquisition channel arranged to receive the digitized signal of each of said transmitters, each of said transmitters comprises a switch arranged between its output and said acquisition channel; the receiver comprises a control output connected to a control line connected to said switches, for controlling each of said switches, so that only one of the outputs is connected to said acquisition channel at the same time.

The receiver includes an acquisition channel, to which are connected all the outputs of the transmitters. The electrical diagram is then simpler. However, the transmission of the measurement is guaranteed, since only one output is electrically connected to said acquisition channel at a time, because the other switches are open. This hardware modification (the addition of a switch to each transmitter) is not very heavy, and the receiver must undergo only a small software modification to control the command lines. It should be noted that the outputs and the acquisition channel are only unidirectional lines: the data only passes from the transmitter to the receiver. Command lines can be considered as analog channels. It is understood that the receiver is also embarked on the vehicle.

Advantageously, the receiver comprises a single command line, and / or includes a single acquisition channel. These implementations simplify the electrical architecture and the wiring.

[0006] Advantageously, said switch of each transmitter is a transistor. Such a transistor, of the NPN type, for example, is effective in imposing an infinite impedance on the output and acting as a switch.

Advantageously, each transmitter comprises a controller or a microcontroller controlled by said control line and arranged to saturate the corresponding transistor to connect the corresponding output to said acquisition channel.

Advantageously, said transistor of each transmitter comprises a base, a collector and an emitter, and the output of each transmitter is connected to the collector of each corresponding transistor, and / or the emitter of each transistor is connected to said trunk channel. acquisition, and / or the base of each transistor is connected to said control line.

Advantageously, each transmitter comprises a resistor arranged upstream of the transistor, to limit the current in the transistor.

Advantageously, the output of each transmitter is a unidirectional channel for transmitting the digitized signal to the receiver, and each transmitter and the receiver are arranged to respectively transmit and receive a digitized signal according to a "SENT" protocol defined by the SAE standard. J2716. This architecture of the acquisition device according to the present invention simplifies the conventional wiring diagram of a "SENT" system operating according to the SAE J2716 standard of January 27, 2010.

A second aspect of the invention is a method of selective signal communication between: - a plurality of transmitters each comprising an output with a switch, arranged to transmit a digitized signal, - a receiver comprising a single channel of an acquisition connected to the outputs for receiving the digitized signal of each of said transmitters, and a control output connected to a control line connected to said switches, the method comprising the steps of: - controlling each of said switches, so only one of the outputs is connected to said acquisition channel; - transmitting a digital signal to the receiver from the transmitter whose output is connected to said acquisition channel.

Advantageously, the transmission step by a transmitter is: - initiated by an initial step of sending by the receiver to said transmitter a specific command sequence of a particular time length and / or a number particular of state changes, sent via said command line, and / or - terminated by a final step of sending by said transmitter to the receiver a specific closing sequence of a particular time length and / or a particular number of state changes, sent via the output. It is conceivable to use only one command line for all transmitters, and to encode a specific command sequence sent on the command line to specifically control a switch of a particular transmitter. Similarly, it may be envisaged to encode an end of transmission message to inform the receiver that all the digitized signal is transmitted.

Advantageously, the transmission step by a transmitter is performed according to a protocol "SENT" defined by the SAE J2716 standard, and wherein the specific command sequence and / or specific closing sequence is a unit of 4 bits. Such a message, similar in form to that of the protocol "SENT" (transmission by nibbles) is well suited, since the transmitters and the receiver are all designed to operate according to this standard.

A third aspect of the invention relates to a motor vehicle comprising at least one device according to the first aspect of the invention, and / or whose measurement data are exchanged according to the method according to the second aspect of the invention.

Other features and advantages of the present invention will appear more clearly on reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the accompanying drawings, in which: - Figure 1 shows an onboard transmitter signal acquisition device of the prior art; FIG. 2 represents an on-board selective signal communication device according to the invention, arranged to transmit digital signals to a receiver; FIG. 3 represents an on-board transmitter of FIG. 2; FIG. 4 represents an operating diagram of the receiver of FIG. 2, according to a transmission control method with pulse counting and message reception; FIG. 5 represents an operating diagram of a first transmitter of FIG. 2 according to the transmission control method with pulse counting and message reception; FIG. 6 represents an operating diagram of a second transmitter of FIG. 2 according to the transmission control method with pulse counting and message reception; FIG. 7 represents an operating diagram of a third transmitter of FIG. 2 according to the transmission control method with pulse counting and message reception; FIG. 8 represents an operating diagram of the receiver of FIG. 2, according to a transmission pulse width transmission and message reception method; FIG. 9 represents an operating diagram of a transmitter of FIG. 2 according to the method of control of transmission in pulse width and reception of message

FIG. 10 represents an operating diagram of the receiver of FIG. 2, according to a method of control of transmission in pulse width and receiver decision; FIG. 11 represents an operating diagram of a transmitter of FIG. 2 according to the method of control of transmission in pulse width and receiver decision.

FIG. 1 represents a diagram of an on-board transmitter signal acquisition device T1 to T3 of the prior art, arranged to transmit a digital signal to a receiver R according to a transmission protocol according to SAE J2716 of January 2010, known as "SENT" standard for "Single Edge Nibble Transmission" in English. The on-board transmitters T1 to T3 are typically responsible for transmitting temperature or pressure values of components of a vehicle engine. These embedded transmitters T1 to T3 and the receiver R are embedded on the motor vehicle, in a space under the hood for example. However, the invention is not limited to under hood sensors or transmitters.

The communication protocol or transmission according to SAE J2716 is a point-to-point protocol: a transmitter communicates to the receiver in a one-way communication. The communication is done by nibbles (nibbles in English) or half byte, the coding of a quartet (nibble in English) is determined between 2 fronts, amounts or descendants. Two fields of communication are possible: either a "Slow channel" in English or "slow channel" via a quartet (nibble in English) on 16 or 18 frames, or a "Fast channel" in English or "fast channel" on one to six quartets (nibble in English) on all frames.

A frame according to this protocol "SENT" is composed of: -1 field synchronization / calibration, -1 field status & communication (slow channel or slow channel nibble), -1 data field (fast channel nibbles or fast channel nibbles), -1 CRC (cyclic redundancy check) field for the fast channel or "fast channel" fast channel "in English, -1 optional pause field.

According to the SAE J2716 standard, each transmitter T1 to T3 sends digital signals to a dedicated output S1 to S3, and is powered by a power path (five volts here), and has a connection to the ground of vehicle.

The onboard device for selective signal communication according to the invention shown in Figure 2 simplifies the architecture of the device of Figure 1, while ensuring operation according to SAE J2716. Indeed, all the onboard transmitters T1 to T3 are connected to a single acquisition channel VA receiver R, and through a switch shown in Figure 3, their output can be connected or not to this acquisition channel VA, by the via an LC command line connected to a control output of the receiver R.

Figure 3 shows a transmitter Ti according to the invention. A resistor R2 and a transistor T are added to the resistor RI and microcontroller MC already present. Via the command line LC, the microcontroller receives from the receiver R the information whether or not to connect the output VSi to the acquisition channel VA. For this purpose, it is sufficient to control the transistor T via its base and the resistor R2 by the microcontroller so that the electrical signals of the output VSi pass on the acquisition channel VA or not.

In other words, via the LC command line, the receiver R can select which of the onboard transmitters T1 to T3 will have its output connected to the acquisition channel, the transistor T of each of the onboard transmitters T1 to T3 acting as a switch.

Several possibilities are offered to control the transistors of each transmitter. It is possible to envisage, in a nonlimiting manner, a control of the transmission towards the receiver R with pulse counting and message reception, or else a control of the transmission towards the receiver in pulse width and message reception, or else in the width of the message. impulse and receiver decision.

Figure 4 shows an operating diagram of the receiver R when the transmission to the receiver R is driven with pulse counting and message reception.

A message (via the slow channel) informing the receiver R of the end of the communication is sent to validate the consistency of the communication and thus change the state of the LC command line to allow another sensor-transmitter Ti to communicate.

The transmitter counts the number of high or low states of the LC control line to know whether it has permission to communicate or not, and control the transistor T accordingly.

After a start DR of the receiver R, the control line LC is set to a high state (LC = 1), the transmitter T1 connects to the acquisition channel VA and starts transmitting to the receiver R, and the receiver R waits for the end of communication of the transmitter T1.

Once the end of the message received from the transmitter T1, the receiver R passes the command line LC to a low state (LC = 0), and then the transmitter T1 disconnects, the transmitter T2 connects to the acquisition channel VA and starts transmitting to the receiver R, and the receiver R waits the end of communication of the transmitter T2.

Once the end of the message received from the transmitter T2, the receiver R passes the command line LC to a low state (LC = 1), and then the transmitter T2 disconnects, the transmitter T3 connects to the acquisition channel VA and starts transmitting to the receiver R, and the receiver R waits the end of communication of the transmitter T3. And another cycle can start again after a delay "temp" for example.

FIG. 5 shows the operating diagram of the transmitter T1, when it is controlled by the receiver R according to the method of FIG. 4. The transmitter T1 comprises a counter CT1 which records the changes in state of the line of LC command (from low state, or said "zero" ("0"), to the high state, or said "a" ("1")). When starting the transmitter T1 (step DT1), the counter CT1 is set to zero.

When the control line LC goes to 1 and the counter CT1 is 0, and the transmitter T1 can connect its output on the VA acquisition channel. A transmission step "T1-comm" begins, and the counter CT1 goes to 1. When the entire digital message has been transmitted, then the transmitter T1 sends an end message ("END").

If the control line LC is ironed to 0, then the transmitter T1 controls its transistor T to go into infinite impedance, to have an open switch status (step "Tr1 open" in Figure 4). If the LC control line remains high, the transistor remains closed.

If the command line goes back to the high state (LC = 1), then the counter CT1 goes to 2 and can then go back to 0, to start a transmission step again if the command line goes back to 1 again. .

FIG. 6 shows the operating diagram of the transmitter T2, when it is controlled by the receiver R according to the method of FIG. 4. During the start DT2 of the transmitter T2, it comprises a counter CT2 of state change. from the control line set to 0, and its transistor is open ("Tr2 open"). During the first change of state of the command line, the counter CT2 goes to 1, and during the change of state of the command line LC to a low state, transmitter T2 can connect its output on the acquisition channel GOES. A transmission step "T2-comm" begins, and when the entire digital message has been transmitted, then the transmitter T2 sends an end message ("END").

When the control line LC goes back to 1, the transmitter T2 controls its transistor T to go into infinite impedance, to have an open switch status (step "open Tr2" in Figure 5) and the counter CT2 to 2 and can then return to 0 at the next change of state of the command line LC, to return to the same state as the start step DT2.

FIG. 7 represents the operating diagram of the transmitter T3, when it is controlled by the receiver R according to the method of FIG. 4. During the DTS start of the transmitter T3, it comprises a counter CTS of change of state of the control line set to 0, and its transistor is open ("Tr3 open"). During the first change of state of the command line, the counter CTS goes to 1, and during the second change of state, the counter CTS does not change, it passes to 1 only during the third change of state (the one to the high state). At this time, the transmitter T3 can connect its output to the VA acquisition channel. A transmission step "T3-comm" begins, and when the entire digital message has been transmitted, then the transmitter T3 sends an end message ("END") and then the command line LC goes low. , and the counter CTS goes to 0 and the transmitter T3 can return to the same state as the start step DTS.

This example is based on three transmitters, but we can of course implement the invention with more than three transmitters. It is sufficient to adapt the counters of the following transmitters.

Figure 8 shows an operating diagram of the receiver of Figure 2, according to a transmission control method pulse width and message reception. The receiver R, on the command line LC sends a given pulse width. Each transmitter measures this pulse width in order to know if it has the authorization or not to communicate. The selected transmitter then sends its messages and the receiver R waits for the reception of an end of communication message to transmit another specific pulse width to another transmitter.

By analogy with the protocol "SENT", it would be possible to compare this pulse width to a width of a quartet which would thus allow a maximum of 15 transmitters on the same line in this configuration.

A pulse width may have several time format (ps or ms), such as for example 3 ps and evolve every 3ps: this gives a pulse width min of 3ps and a maximum pulse width of 45ps. with 15 transmitters.

When starting the receiver R, it comprises a CR counter set to 1. The receiver R sends a first pulse via the LC command line of a first length LLC1 of 3ps, which allows the transmitter Tl to connect its output to the VA acquisition path. Once all the message has been transmitted, the transmitter T1 sends an end of communication message "END Tl". At this moment, the receiver R increases its counter CR by one unit and sends on the command line a pulse of length increased by 3ps. So, that arrived at transmitter Ti, the length of the pulse launched on the command line is LLCi = LLC (i-1) -i-3ps. Or else the length of the pulse launched on the command line LC is LLCi = CR * 3ps, to indicate to the transmitter Ti to communicate with the acquisition channel VA.

As long as the receiver R has not received the end of transmission FIN Ti of the transmitter Ti, it is possible to consider relaunching a pulse length LLCi.

Once all instrucers instructed, the CR counter is at CR = n (total number of transmitters), we can reset the CR counter to 1 and return to the start step DR.

FIG. 9 represents an operating diagram of a transmitter Ti of FIG. 2 according to the pulse width and reception message transmission control method. During the start step DTi, the transistor of this transmitter Ti is open (Tr (i) open). When the transmitter Ti recognizes on the control line LC the pulse width corresponding to its rank, then the transistor Tr (i) is closed to connect the output of this transmitter Ti with the acquisition channel VA, which allows to initiate a communication step "Ti-Comm". Once the digital signal is transmitted in its entirety, an end message is sent, and the transistor goes back to infinite impedance (Tr (i) open).

Figure 10 shows an operating diagram of the receiver of Figure 2, according to a transmission control method pulse width and receiver decision. The receiver R, on the control line LC sends a pulse of a predetermined pulse width for a specified duration (eg 200ms). Each transmitter measures this pulse width continuously to determine whether or not it has permission to communicate.

If he has the authorization, he sends his frames according to SAE J2716 ("SENT") until he no longer see this pulse width on the command line.

At a start step DR, the receiver R begins to send 200ms on the command line LC pulses which all have a width of LLC1 3ps. The first transmitter recognizes this pulse width and connects its output to the acquisition channel.

Then, during a subsequent period of 200ms, the pulse width LLCi is increased by 3ps, and so on until all the transmitters are reviewed.

FIG. 11 represents an operating diagram of a transmitter of FIG. 2 according to the pulse width transmission control method and receiver decision, where after a start step DTi with the transistor Tr (i) open. , the transmitter Ti monitors the command line LC (step SLC). If the pulse width LLCi is detected, then the transmitter T1 closes its switch (the transistor Ti) and starts a transmission step Ti-Comm, until the pulse width on the command line changes and does not change. corresponds more to that of the transmitter Ti.

It will be understood that various modifications and / or improvements obvious to those skilled in the art can be made to the various embodiments of the invention described in this description without departing from the scope of the invention defined by the appended claims. In particular, reference is made to systems with three transmitters, or pulse widths of 3ps, or transmission times of 200ms, but other values for these parameters can be envisaged without departing from the scope of the present invention. invention.

Claims (10)

1. Apparatus for selective signal communication on board a motor vehicle, comprising: - a plurality of transmitters (T1, T2, T3) each comprising an output arranged to transmit a digitized signal, - a receiver (R) connected to the outputs for receiving the digitized signal of each of said transmitters (T 1, T2, T3), characterized in that: - the receiver (R) comprises a single acquisition channel (VA) arranged to receive the digitized signal of each of said transmitters ( T1, T2, T3), - each of said transmitters (T1, T2, T3) comprises a switch arranged between its output and said acquisition channel (VA), - the receiver (R) comprises a control output connected to a line control unit (LC) connected to said switches, for controlling each of said switches, so that only one of the outputs is connected to said acquisition path (VA) at the same time. 2. Device according to the preceding claim, wherein said switch of each transmitter (T 1, T3, T3) is a transistor (T). 3. Device according to the preceding claim, wherein each transmitter (T1, T3, T3) comprises a controller controlled by said control line (LC) and arranged to saturate the corresponding transistor (T) to connect the corresponding output to said channel acquisition (VA). 4. Device according to one of claims 2 or 3, wherein said transistor (T) of each transmitter (T 1, T3, T3) comprises a base, a collector and a transmitter, and wherein the output of each transmitter ( T1, T3, T3) is connected to the collector of each corresponding transistor (T), and / or in which the emitter of each transistor (T) is connected to said acquisition channel (VA), and / or in which the The base of each transistor (T) is connected to said control line (LC). 5. Device according to the preceding claim, wherein each transmitter (T1, T3, T3) comprises a resistor (R2) arranged upstream of the transistor (T), to limit the current in the transistor (T). 6. Device according to one of the preceding claims, wherein the output of each transmitter (T1, T3, T3) is a unidirectional channel for transmitting the digitized signal to the receiver (R), and wherein each transmitter (T1, T3 , T3) and the receiver (R) are arranged respectively for transmitting and receiving a digitized signal according to a "SENT" protocol defined by the SAE J2716 standard of January 27, 2010. 7. A method of selective communication of signals between: a plurality of transmitters (T1, T2, T3) each comprising an output with a switch, arranged to transmit a digitized signal, - a receiver (R) comprising a single channel of FIG. acquisition (VA) connected to the outputs for receiving the digitized signal of each of said transmitters (T1, T2, T3), and a control output connected to a control line (LC) connected to said switches, the method comprising the steps of to: - controlling each of said switches, so that only one of the outputs is connected to said acquisition channel (VA), - transmitting a digital signal to the receiver (R) from the transmitter (T1, T3, T3 ) whose output is connected to said acquisition channel (VA). 8. Communication method according to the preceding claim, wherein the step of transmission by a transmitter (T1, T3, T3) is: - initiated by an initial step of sending by the receiver (R) to said transmitter (Tl, T3, T3) of a specific command sequence of a particular time length and / or a particular number of state changes, sent via said command line (LC), and / or - terminated by a final step sending by said transmitter (T1, T3, T3) to the receiver (R) a specific closing sequence of a particular time length and / or a particular number of state changes, sent via the output . 9. The communication method according to the preceding claim, wherein the step of transmission by a transmitter (T1, T3, T3) is performed according to a protocol "SENT" defined by the SAE J2716 January 27, 2010, and in which the specific command sequence and / or closing specific sequence is a 4-bit unit. 10. Motor vehicle comprising at least one device according to one of claims 1 to 6, and / or whose measurement data are exchanged according to the method according to one of claims 7 to 9.