FR3048098A1 - DEVICE FOR ANALYZING A BI-DIRECTIONAL VIDEO NETWORK BY OBSERVING INTERCHANGEED FRAMES BETWEEN ORGANS - Google Patents

Abstract

An analysis device (DA) is coupled to a communication network (RC) adapted for bidirectional transmission of non-video data frames and for unidirectional transmission of video data frames between (OM, OE1-OE3) members. This device (DA) comprises control means (MCT) enabling a user to select at least a part of at least one frame to be analyzed transmitted by one of the members (OM, OE1-OE3), and means for detection (MD) arranged to observe the frames transmitted on the communication network (RC) and to deliver on an output, during a first selected duration, an alert signal of a chosen value in case of detection of this frame part selected.

Description

The invention relates to communication networks that are suitable for the bidirectional transmission of non-video data frames and the unidirectional transmission of video data frames, and the invention relates to communication networks that are suitable for bidirectional transmission of non-video data frames and for unidirectional transmission of video data frames, and more precisely the analysis of frames flowing in such communication networks.

Certain communication networks of the aforementioned type, and in particular those called "Low Voltage Differential Signaling" (LVDS), comprise a master member and at least one slave member that can exchange frames of bidirectionally non-video data, in slots (or slices) temporally (or) slots (or "slots"), and frames of video data unidirectionally.

The electrical layer (layer 1 in the OSI model) of networks of the aforementioned type is generally standardized. This is for example the case of LVDS networks whose standard is defined in the document TIA / EIA-644 of the ANSI (American National Standards Institute). But this is not the case for the upper layers, and especially for layer 2 (data link) and layer 3. As a result, it is not possible today to analyze in advance. the frames exchanged to determine if they conform to what is expected or if their generation is justified. Therefore, it may happen that once the communication network has been installed, for example in a vehicle, its organs exchange frames erroneous or unplanned, which can be dangerous.

Similarly, it is not possible to determine in an after-sales service if certain failures or malfunctions result from erroneous or unforeseen frames. The invention is therefore particularly intended to improve the situation.

It proposes for this purpose an analysis device for analyzing a communication network adapted to the bidirectional transmission of non-video data frames and the unidirectional transmission of frames of video data between organs.

This analysis device is characterized in that it comprises: control means arranged to enable a user to select at least a part of at least one frame to be analyzed transmitted by one of the organs, and detection means arranged to observe the frames transmitted on the communication network and to deliver on an output, during a first selected duration, an alert signal of a chosen value in case of detection of this selected frame part.

Thanks to the invention, a user can now analyze in advance frames exchanged between organs in order to determine whether they comply with what is expected or if their generation is justified, in order to detect the erroneous or unforeseen frames and to make arrangements to avoid their generation.

The device according to the invention can comprise other characteristics that can be taken separately or in combination, and in particular: its control means can be arranged to allow a user to select a frame portion constituting a sequence of consecutive bits. In this case, its detection means can be arranged to deliver on the output, during the first selected duration, the alert signal of a chosen value in case of detection of this sequence; its control means can be arranged to enable a user to select a frame to be analyzed in a list of frames transmitted by the members and a frame portion constituting a sequence of consecutive bits. In this case, its detection means can be arranged to trigger a delay of a second duration chosen in case of detection of the selected frame, and to deliver on the output, during the first selected period, the warning signal of a value chosen in case of detection of this sequence before the expiration of the timer; > its detection means can be arranged to trigger the delay in case of detection of at least one chosen field defining the selected frame; • each field can be selected from (at least) "ACK", "SYNC", "DEV ADDR", and "ID"; its control means can be arranged to enable a user to select a frame to be analyzed in a list of frames transmitted by the members and a position representing a time shift, in number of bits, of a generation instant of the signal of alert after detection of this selected frame. In this case, its detection means can be arranged to deliver on the output, during the first selected duration, the alert signal of a value chosen at the end of this time offset, defined by this selected position, after detection. of this selected frame; the detection means may be arranged to detect at least one chosen field defining the selected frame; • each field can be selected from (at least) "ACK", "SYNC", "DEV ADDR", and "ID"; its detection means can be part of an electronic card chosen from (at least) an integrated circuit card of the FPGA (Field Programmable Gate Array) type, a microcontroller card, and a specialized circuit card of the type ASIC ("Application-Specific Integrated Circuit"); it can be arranged to analyze an LVDS type communication network, possibly intended to equip a vehicle, possibly of automobile type. Other characteristics and advantages of the invention will appear on examining the following detailed description, and the accompanying drawings, in which: FIG. 1 diagrammatically and functionally illustrates a communication network to which a master unit is connected and at least one slave member, as well as an exemplary embodiment of an analysis device according to the invention, - Figure 2 schematically illustrates a first example of a timing diagram embodying the generation of an alarm signal consecutively to the detection of a sequence of consecutive bits selected in a frame being transmitted, - Figure 3 schematically illustrates a second example of a timing diagram materializing the generation of an alarm signal following the detection of a sequence of consecutive bits selected during a delay triggered following the detection of a frame s lectionnée during transmission, and - Figure 4 schematically illustrates a third exemplary timing diagram embodying the generation of an alarm signal after a selected time offset with respect to the detection of a selected frame. The object of the invention is in particular to propose an analysis device DA capable of being connected to an RC communication network adapted to the bidirectional transmission of non-video data frames and to the unidirectional transmission of video data frames.

In the following, we consider, by way of non-limiting example, that the communication network RC is LVDS type ("Low Voltage Differential Signaling"). But the invention is not limited to this type of communication network. In general, the invention relates to any communication network adapted to bidirectional transmission of non-video data frames and unidirectional transmission of video data frames.

Furthermore, it is considered in the following, by way of non-limiting example, that the RC communication network is intended to be installed in a motor vehicle, such as a car. But the invention is not limited to this application. It concerns any system, installation or apparatus that may comprise at least one communication network adapted to bidirectional transmission of non-video data frames and unidirectional transmission of video data frames. It therefore relates in particular to vehicles, whether terrestrial, maritime (or fluvial), or air, facilities, possibly of industrial type, and buildings.

FIG. 1 schematically shows a nonlimiting example of a (communication) network RC. In this example, the RC network (LVDS type) comprises a bus to which are connected a master member (or node) OM and three members (or nodes) slaves OE1 to OE3 (j = 1 to 3). But the number of slave organs OEj can take any value greater than or equal to one (1). The master organ OM and the slave organs OEj can be of any type, as long as they are involved in the acquisition or use of video data. For example, in the case of a car it can be a multimedia calculator, a touch screen or a camera.

Once connected to an RC network, the master device OM and the slave devices OEj can transmit frames of non-video data in time slots (or slots) that are predefined in a (programming) table, known to each of them. between them.

It is recalled that in an LVDS network the master unit OM can transmit either frames of non-video data called "write frames" Te, or frames of non-video data called headers (or "frames"). header frames ") Th, while each slave organ OEj can transmit frames of non-video data called read frames (or" read frames ") TL respectively in response to frames of non-video data header Th. Th header frame and the associated reading frame T1 are transmitted in the same time slot defined by the table.

A TE write frame is intended to transmit non-video data to a slave member OEj and contains the following fields, always transmitted in the same order: - a synchronization field ("SYNC"), indicating the beginning of the frame, a field ("DEV ADDR"), indicating to which component (serializer, deserializer or slave microcontroller) the frame is addressed, - an identifier ("ID"), allowing the application of the slave organ OEj receiver to know how to decode the functional data field, - a frame length ("DLC"), indicating the size of the frame or the size of the functional data field (in bytes), - the functional data field ("Di"), containing control data (for example the setting of a screen), - a checksum ("CRC" or "CHECKSUM"), to allow the slave member OEj receiver to verify that the received frame has not been altered during the trans mission.

A Th header frame contains the following fields, always transmitted in the same order: - a synchronization field (SYNC), indicating the beginning of the frame, - a field (DEV ADDR), indicating to which component (serializer, deserializer or slave microcontroller) the frame is addressed, - an identifier (ID), allowing the application of the slave member OEj receiver to know how to decode the functional data field, - a frame length (DLC), indicating the size the requested frame (in bytes).

A read frame T1 contains the following fields, always transmitted in the same order: - a first field (ACK), indicating the beginning of the frame, - a functional data field (Di), containing command data (for example data generated by a touch screen indicating which part of the screen is touched by a user), - a checksum (CRC or (CHECKSUM)), to allow the receiving OM master member to verify that the received frame n has not been altered during transmission.

As illustrated in FIG. 1, an analysis device DA according to the invention comprises at least MCT control means and MD detection means.

In the example shown non-limitatively in FIG. 1, the analysis device DA is an "external" device that is temporarily connected to the network RC to be analyzed and to an electronic equipment EE comprising a human / machine interface (keyboard) and a display screen to allow its control by a user. Here, the EE electronic equipment is a personal computer (or PC). But it could be a laptop or an electronic tablet, for example. In this case, the connection between the electronic equipment EE and the analysis device DA may, for example, be of the Ethernet type.

In an alternative embodiment, the analysis device DA could be part of EE electronic equipment (computer (possibly portable) or electronic tablet). In another variant embodiment, the analysis device DA could comprise a human / machine interface (keyboard) and a display screen to allow its direct control by a user.

The MCT control means are arranged to allow a user to select at least a portion of at least one frame to be analyzed transmitted by one of the OM and OEj organs.

In the non-limiting example, the MCT control means must communicate with the electronic equipment EE, in particular to know each selection made by the user. As illustrated without limitation, this communication can be done via an element E1 which is coupled to the control means MCT and the electronic equipment EE. By way of nonlimiting example, this element E1 can be a PXI type chassis ("PCI extensions for Instrumentation"). Alternatively, it could be a VXI type chassis ("VME extensions for Instrumentation"), for example.

Moreover, and as illustrated without limitation, the electronic equipment EE may comprise an interface software Ll providing the interface between the MCT control means and its man / machine interface. By way of non-limiting example, this interface software L1 may be Labview or TestStand.

Also by way of non-limiting example, the MCT control means may be part of an electronic card CE, and more specifically an integrated circuit card type FPGA ("Field Programmable Gaste Array"). But in alternative embodiments, this electronic card CE could be of another type. Thus, it could be a microcontroller card or a specialized circuit card ASIC type ("Application-Specific Integrated Circuit").

It will be noted that in an alternative embodiment the MCT control means could be part of the electronic equipment EE.

The detection means MD are arranged to observe the frames transmitted on the communication network RC and to deliver on an output SD, during a first selected duration of, an alert signal sa of a value chosen in case of detection of the frame part selected by the user.

In the example shown non-limitatively in FIG. 1, the output SD preferably belongs to the electronic card CE.

The frames flowing over the communication network RC are received by an MCN communication module (here of type LVDS) that comprises the analysis device DA and which is coupled to the detection means MD and temporarily connected to the communication network RC . In this case, the connection between the detection means MD (and more precisely here the electronic card CE) and the communication module MCN may, for example, be of UART ("Universal Asynchronous Receiver Transmitter") type-asynchronous transmitter-receiver universal).

In the case of an LVDS type RC communication network, the MCN communication module may be what one skilled in the art calls an LVDS card. This is advantageous because such an LVDS card comprises a subpart ("LVDS MASTER >>) dedicated to the OM master member and a subpart (" LVDS SLAVE >>) dedicated to the slave members OEj. In addition, it allows the LVDS components to be changed in the event of future evolution of the LVDS technology without having to modify the other components of the DA analysis device, which gives the latter (DA) an evolutionary character.

Thanks to the DA analysis device, the user can now analyze in advance frames that are exchanged between OM and OEj organs to determine whether they are what is expected or whether their generation is justified. It can detect frames that are incorrect (that is, contain abnormal information) or that are not expected (that is, that should not be generated due to the living situation ongoing), to try to make arrangements to avoid the generation of these frames.

In order to allow the user to observe the warning signal sa of a chosen value, the output SD of the analysis device DA may, as shown in non-limiting manner in FIG. 1, be connected via a cable to an oscilloscope. OA. The user can thus observe the warning signal sa on the screen of the oscilloscope OA.

It will be noted that the alert signal sa may, for example, have a value chosen chosen as "high" value in the event of detection of the frame portion selected by the user, and have a "low" value in the absence of detection of the frame portion selected by the user. The opposite situation is also possible. For example, if the warning signal sa is analog, its high value can be +5 volts and its low value can be 0 volts. Now, if the warning signal sa is digital, its high value can be equal to 1 and its low value can be equal to 0.

For example, the first selected duration of may be between 0.5 ms and 5 ms. Thus, it may be equal to 1 ms, for example. The chosen value may possibly be configurable.

As illustrated without limitation, the detection means MD may be part of the same electronic card CE that may be part of the MCT control means. But this is not obligatory.

Several observation and detection modes can be implemented by the analysis device DA. Three of these modes are described hereinafter by way of nonlimiting examples with reference to FIGS. 2 to 4 respectively. It will be noted that the same DA analysis device may possibly offer several observation and detection modes among which 'user makes a choice, here via EE electronic equipment. In this case, the MCT control means here provide the electronic equipment EE with an environment enabling the user to choose from a list the mode that he wants to use for his analysis via the human / machine interface of the computer. EE electronic equipment. The identifier of the selected mode is then stored by the MCT control means in a dedicated field c4.

In a first mode of observation and detection the MCT control means are arranged to allow a user to select, here via the electronic equipment EE, a frame portion which constitutes a sequence of consecutive bits seq. Each bit can take the value 0 or 1, and the number of consecutive bits of a seq sequence can be variable. For example, it can be between 1 and 760.

There is therefore no selection here by the user of a particular frame. The goal is indeed to detect the selected sequence seq in any frame.

The MCT control means here provide the electronic equipment EE with an environment enabling the user to manually enter the sequence of consecutive bits that he wants to detect via the man / machine interface of the electronic equipment EE. . It will be noted that, alternatively or in addition, the MCT control means can provide here, to the electronic equipment EE, a list of sequences from which the user can make his choice. This avoids having to perform the seizure of the bits of the seq sequence.

The selected sequence seq is then stored by the control means MCT in a dedicated field c1.

In this first mode, the detection means MD are arranged to deliver on the output SD, during the first selected duration of, the warning signal sa of the chosen value (for example a high value) in case of detection of the sequence selected seq stored in the dedicated field c1 provided by the MCT control means.

A life situation corresponding to the first mode described above is diagrammatically illustrated in the timing diagram of FIG. Frames circulate in the communication network RC and are observed by the detection means MD. At a time t1, the detection means MD detect that the seq sequence selected by the user has just been transmitted in full and in the right order. Consequently, the detection means MD deliver on the output SD, during the first chosen duration of (for example 1 ms), the warning signal sa of a chosen value (here high), which is then displayed, here , on the oscilloscope OA screen.

In a second observation and detection mode, the control means MCT are arranged to enable a user to select, here via the electronic equipment EE, a frame to be analyzed ts in a list of frames transmitted by the OM and OEj members. and a frame portion which constitutes a sequence of consecutive bits seq.

There is therefore here not only a selection by the user of a particular frame ts in a list, but also a selection of a particular sequence seq. The objective is therefore to detect the selected sequence seq in the selected frame ts.

The number of consecutive bits of a sequence seq can be variable. For example, it can be between 1 and 760.

The MCT control means here provide the electronic equipment EE with not only a list of frames from which the user can make a choice via the man / machine interface of the electronic equipment EE, but also an environment allowing the user to manually enter the sequence of consecutive bits seq he wants to detect via the man / machine interface of the electronic equipment EE. It will be noted that, alternatively or in addition, the MCT control means can also provide here, to the electronic equipment EE, a list of sequences from which the user can make his choice. This avoids having to perform the seizure of the bits of the seq sequence.

The selected frame ts is then stored by the control means MCT in a dedicated field c2. Similarly, the selected sequence seq is then stored by the control means MCT in a dedicated field c1.

In this second mode, the detection means MD are arranged to trigger a delay of a second duration chosen dtp in case of detection of the selected frame ts, and to deliver on the output SD, during the first chosen duration of (for example equal to 1 ms), the warning signal sa of a chosen value (for example a high value) in case of detection of the selected sequence seq before the expiry of the time delay dtp. It will be understood that if the selected sequence seq is not detected by the detection means MD during the time delay dtp, then the latter (MD) deliver on the output SD continuously the warning signal sa with another chosen value (by example a low value).

For example, the second chosen duration dtp of the delay time can be between 1 s and 5 s. By way of example, it may be equal to 3 s. This second duration dtp may possibly be previously chosen by the user, for example via the human / machine interface of the electronic equipment EE.

It will be noted that the detection means MD may, for example, be arranged to trigger the time delay dtp if at least one selected field defining the selected frame ts is detected.

In the case of an LVDS type RC communication network, each field may be chosen from at least "ACK", "SYNC", "DEV ADDR", and "ID". It will be understood that the choice of field (s) depends on the type of the selected frame ts. Thus, in the case of a Ts or Th type frame, the detection can, for example, be done on a set ec comprising the first three fields SYNC, DEV ADDR and ID (ie 24 bits), whereas in the case of a Tl-type frame, the detection may, for example, be done on a set ec 'comprising only the first ACK field (ie 8 bits). The bits of the field set (s) ec or ec 'are therefore stored in the dedicated field c2.

A life situation corresponding to the second mode described above is diagrammatically illustrated in the timing diagram of FIG. Frames circulate in the communication network RC and are observed by the detection means MD. At a time t0, the detection means MD detect that the set of fields ec, defining the frame ts selected by the user, has just been transmitted, and therefore they trigger the delay dtp. At a time t1, the detection means MD detect that the seq sequence selected by the user has just been transmitted in full and in the right order before the expiry of the time delay dtp. Consequently, the detection means MD deliver on the output SD, during the first chosen duration of (for example 1 ms), the warning signal sa of a chosen value (here high), which is then displayed, here , on the oscilloscope OA screen.

In a third mode of observation and detection the MCT control means are arranged to allow a user to select, here via the electronic equipment EE, a frame to be analyzed ts in a list of frames transmitted by the OM and OEj organs. and a bit position pb defining a start of the frame portion to be detected.

There is therefore here not only a selection by the user of a particular frame ts in a list, but also a selection of a position pb representing a time shift, in number of bits, of the moment of generation of the signal by the detection means MD after the detection of the particular frame ts.

The MCT control means here provide the electronic equipment EE with not only a list of frames from which the user can make a choice via the man / machine interface of the electronic equipment EE, but also an environment allowing the user to choose a particular position pb defining a time shift of the generation time of the warning signal sa, via the man / machine interface of the electronic equipment EE.

The selected frame ts is then stored by the control means MCT in a dedicated field c2. Similarly, the particular position pb associated with this selected frame ts is then stored by the control means MCT in a dedicated field c3.

In this third mode, the detection means MD are arranged to deliver on the output SD, during the first chosen duration of (for example equal to 1 ms), the warning signal sa of a chosen value (for example a value high) at the end of the time offset, defined by the particular position pb, with respect to the detection of the selected frame ts.

It should be noted that the detection means MD may, for example, be arranged to detect at least one chosen field defining the selected frame ts.

As in the example of the second mode, in the case of an LVDS type RC communication network, each field can be chosen from at least ACK, SYNC, DEV ADDR, and ID. It will be understood that the choice of field (s) depends on the type of the selected frame ts. Thus, in the case of a Ts or Th type frame, the detection can, for example, be done on a set ec comprising the first three fields SYNC, DEV ADDR and ID (ie 24 bits), whereas in the case of a Tl-type frame, the detection may, for example, be done on a set ec 'comprising only the first ACK field (ie 8 bits). The bits of the field set (s) ec or ec 'are therefore stored in the dedicated field c2.

A life situation corresponding to the third mode described above is diagrammatically illustrated in the timing diagram of FIG. Frames circulate in the communication network RC and are observed by the detection means MD. At a time t0, the detection means MD detect that the set of fields ec, defining the frame ts selected by the user, has just been transmitted, and therefore they start counting the bits that follow the last bit of this set ec to the position pb. At a time t2, the detection means MD detect a bit corresponding to the selected position pb, and thus they deliver on the output SD, during the first selected duration of (for example 1 ms), the warning signal sa of a chosen value (here high), which is then displayed here on the oscilloscope OA screen.

It will be noted that the control means MOT may possibly provide, here, for the electronic equipment EE an environment enabling the user to activate or deactivate at any moment the observation and detection function offered by the device. DA analysis via the human / machine interface of EE electronic equipment. The invention advantageously makes it possible to analyze a communication network during its design phase or in an after-sales service as part of a search for failure or malfunction.

Claims (9)

An analysis device (DA) for a communication network (RC) adapted for bidirectional transmission of non-video data frames and unidirectional transmission of frames of video data between organs (OM, OEj), characterized in that it comprises i) control means (MCT) arranged to allow a user to select at least a part of at least one frame to be analyzed transmitted by one of said bodies (OM, OEj), and ii) detection means (MD) arranged to observe the frames transmitted on said communication network (RC) and to deliver on an output, during a first selected duration, an alert signal of a chosen value in case of detection of said part selected frame. 2. Device according to claim 1, characterized in that said control means (MCT) are arranged to allow a user to select a frame portion constituting a sequence of consecutive bits, and said detection means (MD) are arranged to delivering on said output, during said first selected duration, said alert signal of a chosen value in case of detection of said sequence. 3. Device according to one of claims 1 and 2, characterized in that said control means (MCT) are arranged to allow a user to select a frame to be analyzed in a list of frames transmitted by said bodies (OM, OEj ) and a frame portion constituting a sequence of consecutive bits, and said detecting means (MD) are arranged to trigger a delay of a second duration selected in the event of detection of said selected frame, and to deliver on said output, during said first duration chosen, said alert signal of a value chosen in case of detection of said sequence before the expiry of said timer. 4. Device according to claim 3, characterized in that said detection means (MD) are arranged to trigger said timer in case of detection of at least one chosen field defining said selected frame. 5. Device according to one of claims 1 to 4, characterized in that said control means (MCT) are arranged to allow a user to select a frame to be analyzed in a list of frames transmitted by said organs (OM, OEj ) and a position representing a time shift, in number of bits, of an instant of generation of said alert signal after the detection of said selected frame, and said detection means (MD) are arranged to deliver on said output, during said first duration chosen, said alert signal of a value chosen at the end of said time offset, defined by said selected position, after the detection of this selected frame. 6. Device according to claim 5, characterized in that said detection means (MD) are arranged to detect at least one chosen field defining said selected frame. 7. Device according to one of claims 4 and 6, characterized in that each field is selected from a group comprising "ACK", "SYNC", "DEV ADDR", and "ID". 8. Device according to one of claims 1 to 7, characterized in that said detection means (MD) are part of an electronic card selected from a group comprising an FPGA type integrated circuit card, a microcontroller card and a specialized circuit board of the ASIC type. 9. Device according to one of claims 1 to 8, characterized in that it is arranged to analyze a communication network (RC) type LVDS.