FR3036244A1 - SLAVE ORGAN WITH MEANS FOR VERIFYING COMMUNICATION PROTOCOL CHARACTERISTICS, FOR A BIDIRECTIONAL VIDEO NETWORK - Google Patents

Abstract

A slave member (OEj) 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 slave device (OEj) comprises verification means (MV) arranged, in the event of reception of a test configuration frame, for activating and configuring the slave device (OEj) in a state enabling the realization 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 slaves 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 slave 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 exchanging frames of non-video data bi-directionally in time slots (or slices) which are defined by a 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 data frames substantially simultaneously, 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 slave member consecutively upon receipt of a non-video data frame. said writing from the master organ. As is known to those skilled in the art, it is currently very difficult, or even impossible, to verify whether a slave 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 master organ transmits a write frame to a slave member, it can not be certain that the control data it contains are correctly received by this slave member (for example, this write frame perhaps ignored or misinterpreted).

The invention is therefore particularly intended to improve the situation. It proposes, for this purpose, a slave device adapted to be 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 video data frames, according to a protocol defined by characteristics. This slave organ 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 slave 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, and then to control the execution of this test. Thus, it can now be verified whether a slave member can actually take into account (or "consume") at least one characteristic of the protocol, even before it is connected to a communication network. The slave device according to the invention may comprise other characteristics that 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 slave device following a reception a non-video data frame called write, and a second action performed by the slave member at the end of a time delay triggered at the beginning of a transmission time slot allocated to the slave member 3036244; it can be arranged, in the event of reception of a test frame simulating a write frame containing control functional data, to generate, to the external tool, a frame of non-video data called read data. containing this control functional data; its verification means can be arranged, in the event of reception of a test frame relating to the time delay, to order it to transmit, consecutively to this test frame, to the external tool and with a temporal offset. defined in this test frame, a frame of non-video data said reading in the time slot allocated to it and in response to a next header frame transmitted by the external tool; its verification means can be arranged, in the event of reception of a test frame relating to the time delay, to check its reaction at the end of this time 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 the features, and, secondly, at least one slave 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 be apparent from the following detailed description and the accompanying drawings, in which: - Figure 1 schematically and functionally illustrates a vehicle 3036244 4 comprising a communication network to which master and slave members are connected, and FIG. 2 schematically illustrates a test bench comprising an external tool for testing slaves before they equip a system. The object of the invention is notably to propose a slave member OEj 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 frames of video data, according to a protocol defined by characteristics. In the following, we consider, by way of non-limiting example, each slave member OEj is intended to be connected to a communication network RC type LVDS ("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 V, such as a car. But the invention is not limited to this application. It concerns any system, installation or apparatus which may comprise at least one communication network adapted to the bidirectional transmission of non-video data frames and the 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 shows schematically a vehicle V 30 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 bodies 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 may be a multimedia calculator 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) 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 member OEj can transmit read non-video data frames (or" read 15 frames ") TL in response to frames of non-video data header 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 write frame TE 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 receiving slave member OEj 25 to know how to decode the field functional data, - 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 enable the slave member OEj receiver to verify that the received frame has not been altered during the transmission. A TH header frame contains the following fields, always transmitted in the same order: - a synchronization field (SYNC), indicating the start of the frame, 5 - 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 10 bytes). A read frame TL contains the following fields, always transmitted in the same order: - a first field (ACK), indicating the start of the frame, - a functional data field (Di), containing data of 15 commands (by example of the data generated by a touch screen 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 has been impaired during transmission.

As illustrated in FIGS. 1 and 2, a slave device OEj, according to the invention, comprises verification means MV which are arranged, in the event of reception of a test configuration frame, to activate and configure it. in a state allowing 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 realization 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 slave member OEj. 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 FPGA type (" Field Programmable Gate Array "). It should be noted that these verification means MV can be considered as an automaton.

The external tool OX is, for example, a laptop. In the example shown without limitation in FIG. 2, the external tool OX is part of a test bench BT which is able to check the operation of slave members OEj, at least, before they are installed in V vehicles (or systems). But in a variant not illustrated it could be intended to 1 o verify the operation of slave organs OEj, 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 a slave member OEj following receipt of a TE write frame, and a second action performed by a slave member OEj at the end. a delay triggered at the beginning of a transmission time slot allocated to this slave member OEj. 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 external tool OX may initiate a test of a slave organ OEj by transmitting it an initiation test frame similar to a write 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 values: invalid values 2.0 to 2.7 IDENTIFIER 0x00 to Ox3F: identifier of test frame 3036244 8 OxFF: all frames are treated 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 slave member OEj 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 a slave member OEj actually receives the write frames transmitted to it and that it is able to extract the data from these write frames. order they contain. The delayed response service (or "master delay") is intended to verify that a slave organ OEj is actually able to trigger at the beginning of each time slot (of a first duration dl and dedicated to the transmission of 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 slave member OEj in a state allowing the performance of a test of at least one characteristic of the protocol relating to this return and / or for activate their delayed response service and configure their slave member OEj in a state allowing the performance of a test of at least one characteristic of the protocol relating to this deferred response. Of course, other features of the protocol can be tested, and in this case the MV verification means must include an activatable service dedicated to each other feature.

For example, when the forwarding service has been activated and the slave device OEj configured for the return test, the latter (OEj) can be arranged, when it receives a test frame simulating a write frame containing control functional data, for generating, to the external tool OX, a read frame containing these control functional data. We thus test here the characteristic constituting the first aforementioned action. This test frame may, for example, have no test input parameters, and the read frame generated by the slave unit OEj 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 (DO) of the last received test frame (0xFF in the absence of received data) 5 DATA _1 data of byte 1 (D1) of the last 3036244 10 received test frame (0xFF in the absence of received data) ... N DATA_i data of the N-4 byte (DN-4) of the last received test frame (OxFF in the absence of received data) 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 response service has been activated and the slave device OEj configured for the delayed response test, the verification means MV can be arranged, when they receive a test frame relating to the response. timing, to order their slave member OEj to transmit, consecutively to this test frame, to the external tool OX and with a time offset defined in this frame of the test, a reading frame in the time slot which him has been allocated and in response to a next header frame transmitted by the OX external tool. Here we test the characteristic constituting the second action mentioned above. In other words, the verification means MV force their slave member OEj to start the transmission of a read frame (in response to the next header frame) late in the time slot allocated to it. so that at the end of the time associated with this time slot this reading frame has not been fully transmitted and therefore the slave member OEj interrupt its transmission and possibly generates an error frame.

For this service, the test frame may, for example, be a write frame containing as a test input parameter a deferred value ("Slave_DELAY"), for example. For example, if SLAVE_DELAY = 2 and IDENTIFIER = 0x02, the slave member OEj will defer the transmission of its reading frame by 25.6 us (= 2 * 12.8 us) in response to the next frame 25 received header (here of the OX external tool). This read frame generated by the slave member OEj in response to the next received header frame may, for example, be defined as indicated in the following table: Byte Signal Code 1 SERVICE TYPE 0x02: Activation of the service of deferred response (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 Also, for example, when the delayed answer service has been activated and the The slave device OE j configured for the delayed response test, the verification means MV can be arranged, when they receive a timing test frame, to check the reaction of their slave member OEj at the end of the test. timing corresponding to the next header frame transmitted by the external tool OX, 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). It should be noted that the same test can relate to several characteristics. In this case, a first characteristic with at least one dedicated test frame is tested, 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 slave member OEj 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 slave member OEj an end of test frame similar to a write 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 slave member and allowing 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 duration of the validation phases of the slave organs and the skills necessary to analyze the test results of the slave organs.

Claims (9)

REVENDICATIONS1. A slave organ (OEj) 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 frames of video data, 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 slave device (OEj) 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. slave organ according to claim 1, characterized in that each characteristic of said protocol is selected from a group comprising a first action performed by said slave member (OEj) consecutively to a receipt of a non-video data frame called writing , and a second action performed by said slave member (OEj) at the end of a time delay triggered at the beginning of a transmission time slot allocated to said slave member (OEj). 3. Slave organ according to claim 2, characterized in that, in the case of receiving a test frame simulating a write frame containing control functional data, it is arranged to generate, destined for said external tool ( OX), a read non-video data frame containing said control functional data. 4. Slave member according to one of claims 2 and 3, characterized in that said verification means (MV) are arranged, in case of reception of a test frame relative to said delay, for ordering said slave member (OEj ) to transmit, consecutively to this test frame, to said external tool (OX) and with a time offset defined in said test frame, a frame of non-video data called read in the time slot which has been allocated to it and in response to a next header frame transmitted by said external tool (OX). 3036244 14 5. Slave member according to one of claims 2 to 4, characterized in that said verification means (MV) are arranged, in case of reception of a test frame relative to said delay, to check the reaction of said slave member (OEj) at the end of a delay corresponding to a next header frame transmitted by said external tool (OX), and record a result of this reaction. 6. Slave organ 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 slave member (OEj) in 10 a state of operation said normal and to turn off. A vehicle (V) comprising a communication network (RC) adapted for the bidirectional transmission of non-video data frames, in time slots defined by a table, and the unidirectional transmission of video data frames, according to a defined protocol by characteristics, characterized in that it comprises at least one slave member (OEj) 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. 20 9. Vehicle according to one of claims 7 and 8, characterized in that said communication network (RC) is of type LVDS.