FR3036243A1 - MASTER ORGAN WITH MEANS FOR VERIFYING COMMUNICATION PROTOCOL CHARACTERISTICS, FOR A BIDIRECTIONAL VIDEO NETWORK - Google Patents

Abstract

A master organ (OM) is adapted to be connected to a communication network adapted for bidirectional transmission of non-video data frames, in time slots defined by a table, and for unidirectional transmission of video data frames, according to a protocol defined by characteristics. This master organ (OM) comprises verification means (MV) arranged, in the event of reception of a test configuration frame, for activating and configuring the master device (OM) in a state enabling the production of a test of at least one selected characteristic of the protocol, defined by at least one test frame transmitted by an external tool (OX), and then to control the execution of the test.

Description

The invention relates to master devices intended to be connected to communication networks adapted to the bidirectional transmission of non-video data frames and to the transmission of data. unidirectional video data frames, and more specifically the verification of the operation of such master organs. In certain communication networks of the above-mentioned type, and in particular in so-called "low voltage differential signaling" (LVDS), a master member and at least one slave member are arranged in such a way that exchange non-video frames of data bidirectionally, in slots (or slices) temporal (s) (or "slots") that are defined (s) by a schedule table (or "schedule table"), and frames of video data unidirectionally. This (programming) table advantageously makes it possible to prevent two members (or nodes) transmitting substantially non-video frames of data at the same time, which would lead to their loss. For example, the loss of a non-video screen parameter data frame between a multimedia computer and a touch screen of a vehicle could, for example, induce a failure to take account of a setting controlled by a passenger and therefore an undesirable effect on the touch screen. The bidirectional transmission of non-video data frames is done according to a communication protocol which is defined by characteristics, such as the action that is performed by the master member consecutively upon receipt of a so-called non-video data frame. reading. As is known to those skilled in the art, it is currently very difficult, or even impossible, to verify whether a master organ is actually able to take into account (or "consume") a characteristic of the communication protocol, including before it is connected to a communication network. As a result, certain requirements of the communication network can not be guaranteed. For example, when a slave unit transmits a read frame to a master member, it can not be certain that the control data it contains is correctly received by that master member (for example, this read frame may to be ignored or misinterpreted).

The object of the invention is, in particular, to improve the situation. It proposes for this purpose a master device capable of being connected to a communication network adapted to the bidirectional transmission of non-video data frames, in time slots defined by a table, and to the unidirectional transmission of 15 frames of video data. according to a protocol defined by characteristics. This master device is characterized by the fact that it comprises verification means arranged, in the event of reception of a test configuration frame, to activate and configure the master device in a state which allows the realization of a test of at least one chosen characteristic of the protocol, defined by at least one test frame transmitted by an external tool, then to control the realization of this test. Thus, it can now be verified whether a master organ can actually take into account (or "consume") at least one characteristic of the protocol, even before it is connected to a communication network. The master member according to the invention may comprise other characteristics which may be taken separately or in combination, and in particular: each characteristic of the protocol may be chosen from at least one first action performed by the master member consecutively to a receiving a read non-video data frame, and a second action performed by the master member at the end of a triggered delay at the beginning of a transmit time slot allocated to the master member; it can be arranged, in the case of receiving a test frame simulating a read frame containing control functional data, to generate, to the external tool, a non-video data frame called a write frame containing this control functional data; its verification means can be arranged, in the event of reception of a test frame relating to the delay, to order it to transmit, in response to this test frame, to the external tool and with an offset time defined in this test frame, a frame of non-video data called writing in the time slot that has been allocated to it; its verification means can be arranged, in the event of reception of a test frame relating to the delay, to check its reaction at the end of this delay, and record a result of this reaction; its verification means can be arranged, in the event of reception of an end-of-test frame, to reconfigure it into a state of normal operation and to deactivate. The invention also proposes a vehicle, possibly of automobile type and comprising, on the one hand, a communication network adapted to the bidirectional transmission of non-video data frames, in time slots defined by a table, and to the transmission unidirectional video data frames, according to a protocol defined by characteristics, and, secondly, at least one master member of the type shown above and connected to the communication network. The invention is particularly well suited, although not exclusively, in the case where the communication network is of the LVDS type. Other features and advantages of the invention will become apparent upon examination of the detailed description below, and the accompanying drawings, in which: FIG. 1 schematically and functionally illustrates a vehicle comprising a communication network to which are connected master and slave members, and - Figure 2 schematically illustrates a test bench comprising an external tool for testing master bodies before they equip a system.

The object of the invention is notably to propose a master OM capable of being connected to an RC communication network adapted to the bidirectional transmission of non-video data frames, in time slots defined by a (programming) table, and to unidirectional transmission of video data frames, according to a protocol defined by characteristics. In the following, it is considered, by way of non-limiting example, that each OM master member is intended to be connected to an LVDS type communication network ("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 for 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 V, such as for example 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 vehicle comprising 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 0E1 to 0E3 (j = 1 to 3). But the number of slave organs OEj can take any value greater than or equal to one (1).

The master member OM and the slave members 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 may be a multimedia computer or a touch screen.

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) which 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 referred to as header (or " header frames ") TH, while each slave member OEj can transmit frames of non-video read data (or" read frames ") TL in response to frames of non-video data 15 head TH respectively. Furthermore, a header frame TH and the associated read frame TL 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 field of functional data, 25 - 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 adjustment of a screen), - a checksum (CRC), to allow the slave member OEj 30 receiver to verify that the received frame has not been altered during transmission.

3036243 6 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 of the requested frame (in bytes).

A read frame TL 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 (by example of the data generated by a touch screen 15 indicating which part of the screen is touched by a user), - a checksum (CRC), to allow the receiving OM master member to verify that the received frame has not not been impaired during transmission. As illustrated in FIGS. 1 and 2, an OM master member, according to the invention, comprises MV verification means which are arranged, in the event of reception of a test configuration frame, to activate and configure it. in a state enabling the performance of a test of at least one chosen characteristic of the (communication) protocol, defined by at least one test frame transmitted by an external tool OX, then to control the execution of this test. These verification means MV may, for example, be made in the form of software modules (or computer or "software") stored in a memory of a master member OM. But in a variant they could be made in the form of a combination of electronic circuits (or "hardware") and software modules, as is for example the case of an integrated circuit of the FPGA type (" Field Programmable Gate Array "). It should be noted that these verification means MV can be considered as an automaton. The OX external tool is, for example, a laptop. In the example illustrated nonlimitingly in FIG. 2, the external tool OX is part of a test bench BT which is able to verify the operation of OM master organs, at least, before they are implanted in V vehicles (or systems). But in a variant not illustrated it could be intended to verify the operation of OM master organs, at least after they have been implanted in vehicles V (or systems). Each characteristic of the protocol may, for example, be chosen from at least one first action performed by the OM master member following a reception of a read frame TL, and a second action performed by the master unit OM at the end. a time delay triggered at the beginning of a transmission time slot allocated to the master member OM. The first action is associated with the return service (or "loopback") described below, and the second action is associated with the service of delayed response (or "master delay") also described below. For example, the OX external tool may initiate a test of an OM master member by transmitting to it an initiation test frame similar to a read frame. This initiation test frame may, for example, be defined as indicated in the following table: Bit Signal Code 1.0 to 1.7 SERVICE TYPE 0x00: deactivation of the test service 0x01: activation of the return service 0x02: activation of the deferred service response other: invalid values 2.0 to 2.7 IDENTIFIER 0x00 to Ox3F: identifier of the test frame OxFF: all the frames are processed 3036243 8 as test frames 3.0 to 8.7 Test input parameters defined for each service In this case table, a service is a function that is provided by the MV verification means during a test. Preferably, if the service defines less than six bytes of test input parameters, the frame is completed up to eight bytes of data with 0xFF stuffing bytes. The return service (or "loopback") is intended to constrain the OM master member to send back to the external tool OX data contained in a corresponding test frame transmitted by the latter (OX). This service, which corresponds to a characteristic of the protocol, is intended to verify that an OM master member actually receives the read frames transmitted to it and that it is able to extract the control data from these read frames. they contain. The delayed response service (or "master delay") is intended to verify that an OM master member is actually capable of triggering at the beginning of each time slot (of a first duration d1 and dedicated to the transmission of time). less than one non-video data frame) allocated to it, a time delay of a second duration d2 strictly less than d1, and to terminate transmission when the end of this time delay occurs while the non-video data frame has not been fully transmitted. This characteristic of the protocol makes it possible to avoid the collision between a part of a first frame likely to be transmitted in the next time slot and a second frame transmitted in this next time slot, thanks to the interruption of the transmission of the end. of the first frame. This makes it possible to lose only the first frame, and no longer the second frame. Thus, the verification means MV may be arranged to activate their forwarding service and configure their OM master member in a state 3036243 9 allowing the realization of a test of at least one characteristic of the protocol relating to this reference and / or for activate their delayed response service and configure their OM master member in a state allowing the performance of a test of at least one protocol characteristic relating to this deferred response. Of course, other characteristics of the protocol can be tested, and in this case the means of verification must include an activatable service dedicated to each other characteristic. For example, when the forwarding service has been activated and the master unit OM configured for the return test, the latter (OM) can be arranged, when it receives a test frame simulating a read frame TL containing control functional data, for generating, to the external tool OX, a TE write frame containing this control functional data. The characteristic constituting the first aforementioned action is tested here. This test frame may, for example, have no test input parameters, and the write frame generated by the master unit OM in response to this test frame may, for example, be defined as indicated in FIG. following table: Byte Signal Code 1 SERVICE TYPE 0x01: activation of the forward service _ (SERVICE TYPE of the last received test frame) 2 IDENTIFIER identifier of the last received test frame 3 LENGTH length of the last received test frame 4 DATA 0 data of byte 0 (OD) of the last received test frame (0xFF in the absence of received data) 5 DATA _1 data of byte 1 (D1) of the last received test frame (0xFF in l absence of 3036243 10 received data) ... N DATA_i data of the N-4 byte (DN-4) of the last received test frame (OxFF in the absence of data received) In this last table N is the total number of bytes of control data contained in the last received test frame. Also, for example, when the delayed answer service has been activated and the OM master configured for the delayed response test, the verification means MV can be arranged, when they receive a test frame relating to the response time. timing, to order their master member OM to transmit, in response to this test frame, to the external tool OX and with a time offset defined in this test frame, a write frame in the time slot which has been allocated to him. Here we test the characteristic constituting the second action mentioned above. In other words, the verification means MV force their master unit OM to late start the transmission of a write frame in the time slot allocated to it, so that at the end of the associated delay 15 at this time slot this write frame has not been fully transmitted and therefore the master member OM interrupts its transmission. For this service, the test frame may, for example, be a write frame or a header frame containing as a test input parameter a deferred value ("MASTER_DELAY"), for example. By way of example, if MASTER_DELAY = 2 and IDENTIFIER = 0x02, the master unit OM will defer the transmission of its write frame by 200 ps (= 2 * 100 us). This write frame generated by the master unit OM in response to the test frame may, for example, be defined as indicated in the following table: Byte Signal Code 3036243 11 1 SERVICE TYPE 0x02: activation of the answer deferred service (SERVICE_TYPE of the last received test frame) 2 IDENTIFIER identifier of the last received test frame 3 not used OxFF ... N not used OxFF In this last table N is the total number of bytes of control data contained in the last test frame received. Also, for example, when the delayed answer service has been activated and the OM master configured for the delayed response test, the verification means MV can be arranged, when they receive a test frame relating to the response time. timing, to check the reaction of their OM master member at the end of this delay, and record a result of this reaction. This result can, for example, be represented by a code 10 whose first value represents a successful test (in the case of taking into account the deferred response), and a second value represents a failed test (in the case of a response). a failure to take into account the deferred answer). The result can also, for example, be observed by analyzing frames sent by the master OM.

It should be noted that the same test may relate to several characteristics. In this case, a first characteristic is tested with at least one dedicated test frame, then the second characteristic is tested with at least one dedicated test frame, and so on. It will also be noted that the verification means MV may possibly be arranged, in the event of reception of an end-of-test frame from the external tool OX, for reconfiguring their master device OM in a so-called normal operating state and for disable yourself. For example, the external tool OX can trigger the deactivation of the verification means MV by transmitting to their master device OM a test end frame similar to a read frame. This end of test frame can, for example, be defined as indicated in the following table: Bit Signal Code 1.0 to 1.7 SERVICE TYPE 0x00: deactivation of the test service 2.0 to 2.7 IDENTIFIER OxFF 3.0 to 8.7 data of padding bytes OxFF command The invention advantageously makes it possible to test any characteristic of the communication protocol used for transmitting the control frames to the master device and enabling the latter to perform internally certain functions that are useful for managing the transmissions within its body. communication network. This makes it possible to significantly reduce the durations of the validation phases of the master organs and the skills necessary for the analysis of the test results of the master organs.

Claims (9)

REVENDICATIONS1. A master organ (OM) adapted to be connected to a communication network (RC) adapted for bidirectional transmission of non-video data frames in time slots defined by a table and unidirectional transmission of video data frames according to a protocol defined by characteristics, characterized in that it comprises verification means (MV) arranged, in case of reception of a test configuration frame, to activate and configure said master member (OM) in a state allowing the performance of a test of at least one selected characteristic of said protocol, defined by at least one test frame transmitted by an external tool (OX), and then to control the realization of said test. 2. Master member according to claim 1, characterized in that each characteristic of said protocol is selected from a group comprising a first action performed by said master member (OM) consecutively to a reception of a non-video data frame called read, and a second action performed by said master member (OM) at the end of a time delay triggered at the beginning of a transmission time slot allocated to said master member (OM). 3. Master member according to claim 2, characterized in that it is arranged, in the case of receiving a test frame simulating a read frame containing control functional data, to generate, to said external tool (OX ), a non-video data frame called writing containing said control functional data. 4. Master member according to one of claims 2 and 3, characterized in that said verification means (MV) are arranged, upon receipt of a test frame relative to said delay, to order said master member (OM ) to transmit, in response to this test frame, to said external tool (OX) and with a time offset defined in said test frame, a non-video data frame said writing in the time slot that has been allocated. 5. Master member according to one of claims 2 to 4, characterized in that 3036243 14 said verification means (MV) are arranged, in case of reception of a test frame relative to said delay, to verify the reaction of said master unit (OM) at the end of this delay, and record a result of this reaction. 5 6. Master member according to one of claims 1 to 5, characterized in that said verification means (MV) are arranged, in case of reception of an end of test frame, to reconfigure said master member (OM) in a state of operation said normal and to turn off. 7. Vehicle (V) comprising a communication network (RC) adapted for bidirectional transmission of non-video data frames, in time slots defined by a table, and for unidirectional transmission of video data frames, according to a protocol defined by characteristics characterized in that it comprises at least one master member (OM) according to one of the preceding claims, connected to said communication network (RC). 8. Vehicle according to claim 7, characterized in that it is automotive type. 9. Vehicle according to one of claims 7 and 8, characterized in that said communication network (RC) is of type LVDS.