JP3026359B2 - Data communication method in in-vehicle communication network - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a data communication method in a vehicle-mounted communication network, and more particularly to a data communication method suitable for use as a connection network for a vehicle-mounted AV (audio-visual) system. Related to the communication method.

[Conventional technology]

In recent years, in-vehicle audio systems have evolved from systems that merely listen to music to systems that include visual elements. A system having not only audio but also visual functions is known as an AV system.

In-vehicle AV systems are constructed with various elements. For example, the audio element includes a cassette tape deck, a radio tuner, a CD (compact disc) player, and the visual element includes a TV.
(Television) A tuner, a navigation device, and the like are included. An audio reproduction signal output from each of these elements is reproduced from a speaker mounted in the vehicle via an amplifier, and an image reproduction signal is similarly output as an image on a display mounted in the vehicle. Today, each of these elements is controlled by digital technology, which is controlled by a microcomputer-based controller.

In order to operate each of the above elements systematically,
It is necessary to control each element comprehensively. Therefore, in the on-vehicle AV system, the controllers of the above elements are connected by a bus network, and mutual control data is transmitted and received via a communication bus constituting the network.

In a conventional network, each controller is controlled by a polling method. The polling method is a method in which one of the controllers is given a priority position, the controller is set as the master, and the remaining controllers are set as the master-slave relationship, and the master is always used when the master collects data from the slave. This is a method for accessing the slave side from the server.

When the master transmits and accesses communication data to the slave by the conventional polling method, or when the slave returns data to the master, it is necessary to identify or specify each controller. Therefore, an address indicating the controller is assigned to each controller.

In the conventional address assignment method, a unique address is assigned to each controller. The control data includes instruction data (for example, a start instruction: O
N data). Therefore,
The communication data transmitted / received on the communication bus is almost the same as the number of connection elements.

[Problems to be solved by the invention]

The problems with the conventional connection network are that there is a lot of communication data transmitted and received on the communication bus and that the data is complicated. That is, as described above, for example, the command system of the communication data transmitted from the master side is a fixed one which is determined in advance corresponding to each connection element corresponding to each connection element, and the number thereof is large. . Therefore, if an attempt is made to extend the AV system by adding a new element, the command for the additional element must be increased accordingly.

An object of the present invention is to provide a data communication method in an in-vehicle communication network capable of simplifying a command system of communication data, improving the expandability of an AV system, and improving the degree of freedom of a connection relationship.

[Means for solving the problem]

 FIG. 1 is a diagram illustrating the principle of the present invention.

As shown in FIG. 1, the present invention provides one master device M
And one or more slave devices S ₁ to S _n is a data communication method in a vehicle communication network of bus method comprising connected to the same communication bus B, the master device M and the slave device S ₁ to S _n is assigned a physical address indicating the device, and the master device M
And an assignment step of assigning a logical address indicating the function of each with the respective device is a slave device S ₁ to S _n, and a data generating step of generating address data ADR in combination with the logical address LA and the physical address PA , by sending the communication data DT including the address data ADR said generated on the communication bus B, and a communication step of performing data communication between the master device M and the slave device S ₁ to S _n mutually The address data ADR is configured to include at least the physical address MA indicating the source of the communication data DT and the physical address SA indicating the destination of the communication data.

[Action]

According to the present invention, in the assignment step assigns a physical address indicating the device to each of the master device M and the slave device S ₁ to S _n, and the each of the master device M and the slave device S ₁ to S _n A logical address indicating the function of each device is assigned.

Next, in a data generation step, address data ADR is generated by combining the physical address PA and the logical address LA.

Then, in the communication process, by sending the communication data DT including the generated address data ADR on the communication bus B, performs data communication between the master device M and the slave device S ₁ to S _n from each other.

At this time, the communication data DT is included in the address data ADR.
, And at least a physical address SA indicating a transmission destination of the communication data.

For example, when the master device M has two functions (for example, a tuner and a tape deck), the communication data including some command from the slave device S1 to _one function (for example, the tuner) of the master device M. When transmitting DT, the communication data DT contains the physical address data PA _M
Address data ADR consisting of logical address data LA _M1
And the data D is added. Further, for example, the other functions of the master device M from the slave device S ₁ (for example, a tape deck) when transmitting the communication data DT respect, the communication data DT is composed of physical address data PA _M and the logical address data LA _M2 The configuration is such that data D is added to the address data ADR.

Thus, even when a plurality of different functions are added to one master device M, the physical address data
The PA is the same, and only the logical address data LA needs to be changed. Therefore, unlike the related art, it is not necessary to set an address in a fixed state from the beginning for each device by the number of functions, and the command system of the communication data DT can be simplified. Also, even when a new device or function is added, the physical address PA and the logical address LA
Alternatively, it is possible to provide the additional device or additional function simply by additionally setting only the logical address LA,
It is possible to improve the expandability of the AV system and further improve the degree of freedom in connecting the devices.

Furthermore, the address data ADR includes at least the physical address MA indicating the transmission source of the communication data DT and the physical address SA indicating the transmission destination of the communication data. On the other hand, when a reply is sent from the transmission destination device, it is possible to quickly recognize the transmission source device and execute the reply without fail.

Furthermore, a physical address MA indicating the transmission source of the communication data DT and a physical address indicating the transmission destination of the communication data DT
Since at least the SA is included, even when a new device is added in the network, the physical address PA of the device is immediately recognized by the destination device by the physical address MA having the source as the source. The destination device can easily and quickly recognize that the new device has been added, and the source device can immediately recognize the source device. Processing corresponding to the transmission source device can be quickly started in the transmission destination device.

〔Example〕

Next, a preferred embodiment of the present invention will be described with reference to the drawings.

Power supply system of AV system The present invention is preferably applied to a vehicle-mounted AV system. As shown in FIG. 2, the AV system 103 receives power supply from the car battery 101 via the ACC switch 102. The ACC switch 102 is a switch that is linked to an engine key of the vehicle. By rotating the engine key to the position of the ACC switch 102, power is supplied to accessories in the vehicle. Therefore, in general, the power supply to the AV system 103 is repeatedly turned on / off each time the engine key is turned.

Example of Configuration of AV System FIG. 3 shows an example of the configuration of an AV system to which the present invention is applied. In the example of FIG. 3, a tape deck 6 for reproducing a recording signal from a cassette tape 1, a tuner 7 such as an FM for reproducing a radio wave received by an antenna 2, and a CD player for reproducing a recording signal from a CD 3 are used as an audio reproducing apparatus. 8
And a multi-CD player 9 including an auto-changer 5 for reproducing a recording signal from each CD of the multi-CD 4.
As the visual playback device, the TV received by antenna 2
A TV tuner (assumed to be built into the tuner 7) for reproducing radio waves or a CD-ROM 8
And a display 12 for outputting the recorded still image via the CD player 8. CD-RO
A typical example of using M is a navigation device. The external commander 10 includes a keyboard for inputting various operation commands from outside. The input device 13 can also be incorporated in the external commander 10.

Each of the above devices has a controller for controlling its own operation, and the controllers are connected to each other via a communication BUS 14 to form a bus-based control network. The structure of this network is shown in FIG. 4, and the details will be described later.

On the other hand, the reproduced signal of the audio reproducing apparatus is selectively input to the digital amplifier 16 via the selector 15 and is amplified by a predetermined amount and then emitted from the speaker 17. A digital signal circuit included in the digital amplifier 16 is also controlled by a built-in controller, and this controller is also connected to the communication BUS.

AV System Control Network FIG. 4 shows an example of an AV system control network. Here, for convenience of explanation, in FIG.
Each device connected to S14 is referred to as a “unit” as a general expression. As shown in FIG. 4, each unit is connected to the communication BUS 14 in parallel. One of the units is referred to as a “master” in order to control the entire network, and this is indicated by a master unit 200. Are all other remaining units "slave", these slave units 200 _-1 to 200
Shown by _-n .

Master controller 1 built in master unit 200
8 is connected to the communication BUS 14 via the communication interface IC25. In this example, the master controller 18 also controls the tape deck 6 and the tuner 7. Each of the slave controllers 19 to 24 built in the slave units 200 _-1 to 200 _-n is similarly connected to the communication BUS 14 via the communication interface ICs 25 to 31.

FIG. 5 shows the master unit 200 and the slave unit 200.
A specific example of the connection state with _-n is shown. As shown in FIG.
Communication BU between master unit 200 and slave unit 200- _n
Connected by S14. The communication BUS 14 uses a twisted pair line composed of two lines. The communication data DT transmitted and received via the communication BUS 14 is transmitted to the communication interface IC 25 of the master unit 200 and the slave unit 200- _n.
And the communication interface IC31. The communication interface IC 25 is a communication driver / receiver 32
Similarly, the communication interface IC31 is separated into a communication driver / receiver 35 and a communication control IC36. In this regard, in the related art, it has been provided integrally in one IC. The communication control IC 33 is formed of CMOS transistors and has a communication driver /
The receiver 32 is formed of a bipolar transistor having a high current driving capability. The same applies to the communication driver / receiver 35 and the communication control IC 36.

Thus, regarding the communication interface IC 25, the communication control IC 33 and the communication driver / receiver 32
This makes it possible to cope with a change in the transmission medium of the communication BUS 14. For example, in the example of FIG.
Although a twisted pair wire is used as the communication BUS 14 for differential transmission, as shown in FIG. 6, when an optical communication cable 40 is used as the communication BUS 14, a communication driver / receiver
By using the electro-optical converter 38 instead of 32, it is possible to cope without changing other configurations. Further, the operation failure generated in the master unit 200 is largely due to disturbance noise mixed in from the communication BUS 14, and even if an excessive signal is mixed in for some reason, the communication driver / receiver 32 alone often fails. /
By replacing only the receiver 32, it is easy to return to the current state, which is advantageous for maintenance. In particular, for automotive
In the case of an AV system, there are many opportunities to mix noise generated from the engine system of an automobile, so that it is effective.

Also, from the viewpoint of IC manufacturing, it is easier to manufacture the IC and the cost is more advantageous if the CMOS transistor and the bipolar transistor having different manufacturing processes are separated from each other than the configuration of the Bi-CMOS IC. .

Incidentally, the above description has described a communication interface IC 25, and is separated into a communication driver / receiver and the communication control IC Similarly for communications interface IC26~31 the other slave units 200 _-1 to 200 DEG _-n.

Next, the transmission format of the communication data DT used in the present invention will be described.

FIG. 7 shows an example of a transfer format of the communication data DT. As shown in FIG. 7, the communication data DT, the master address data MA from the head indicates the address of the master unit 200, slave address SA indicating the addresses of the slave knit 200 _-1 to 200 DEG _-n, the message length of data D It comprises message length data N, classification data TP indicating the type of data D, and data D indicating transfer contents.

The configuration of the data D is the content of the communication data DT,
It differs depending on the classification data TP, and is roughly classified into three types of format configurations. As shown in FIG. 10, the first format is a format for confirming connection, the second format is a format for keys, display data, and the like, and the third format transmits a result of a checksum CS. Format. Furthermore, the format for confirming the connection is to transfer the communication data DT to the slave units _200-1 to 200-2.
The transfer from 00 _-n to the master unit 200 is different from the transfer from the other unit. In FIG. 10, the format of the key and the display data is the same from the physical status data PS to the logical mode data LM in the data configuration, and is not shown.

The classification data TP is a data area which is arranged at the head of the communication data DT and indicates the type of data D following the classification data TP. The classification data TP is composed of large classification data and small classification data. The major classification data is as shown in FIG.
Indicates the type of data D. Bit allocation is classified data TP
If the whole is 8 bits, the upper 4 bits are assigned. As shown in FIG. 9, the small classification data is mainly used to identify the format of the data D, and the lower 4 bits are allocated.

Physical address data PA is Figure 11, as shown in FIG. 12, the communication interface of the master unit 200 to slave unit 200 _-1 to 200 DEG _-n on the communication BUS 14 IC25～
This is an address in communication for specifying 31 and is an address indicating the master unit 200 and the slave units 200 _-1 to 200 _-n . Of the physical address data PA, the physical address data PA that specifies the master unit 200 is always fixed. As for the physical address data PA, basically, one physical address data PA is assigned to one unit. FIG. 15 shows an example in which physical address data PA is assigned in association with the unit configuration in FIG. In addition,
In FIG. 15, the physical address data PA is also set in the master controllers 18 to 24. This is because, like the master unit 200, the two functional elements of the tape deck 6 and the tuner 7 are provided in one controller master controller 18. Is connected. In a combination of one controller and one function, the physical address data PA and the logical address data LA have the same address as in the slave controllers 19 to 24.

The physical status data PS is status information relating to the master unit 200 and the slave units 200 _-1 to 200 _-n , and includes a functional address (that is, logical address data L to be described later) of the unit.
This is data indicating the number of A).

As shown in FIG. 13, the logical address data LA is data indicating the functions (that is, tuners and tape decks) of the units of the master unit 200 and the slave units 200 _-1 to 200 _-n. Assigned for each. The number of logical address data LA is equal to the number of functions assigned to the controller determined by the physical address data PA.
It is not a fixed number because it is added like ₁ , LA ₂ .... FIG. 14 shows an example in which logical address data LA is allocated in association with the unit configuration in FIG.

The talker address data TL indicates the address of the transmission source (speaker) transmitting the communication data DT.

The listener address data LN indicates an address of a transmission destination (listener) for receiving the communication data DT.

The logical status data LS contains each logical address.
Indicates the state of the function corresponding to LA.

The logical mode data LM indicates an operation state (mode) of a function corresponding to each logical address.

The checksum data CS is data for error detection added in order to improve the reliability of the data D.

Communication operation In the AV system described above, the master unit 20
Communication data D between 0 and slave units 200 _-1 to 200 _-n
The operation when communicating T will be described below.

FIG. 15 shows a specific example. FIG. 15 shows an example of a connection confirmation sequence in a case where a slave unit including a TV / FM tuner and a master unit perform access confirmation access to their own AV system from the slave unit side.

In this network, unlike the conventional polling method, all slave units self-declare their own units to the master unit. The master unit does not actively access the slave unit.

Now, in FIG. 15, because the slave unit is connected confirmation request (self-reported), to transmit to the master unit via the communication BUS14 issue the communication data DT _1. At this time, the communication data DT ₁ sets its own physical address data PA to “1”.
23H "(H is hexadecimal hexadecimal), the physical address data PA of the partner master unit is" 100H ", and the logical address data indicates that the own sleeve unit has a configuration including a TV tuner and an FM / AM tuner. This is indicated by LA ₁ = 05 and logical address data LA ₂ = 07. (See Fig. 13.) The communication data DT ₁ allows the master unit 200 to set PA = 123H and LA
It is registered that a unit having the functions of ₁ = 05 and LA ₂ = 07 is connected to the communication BUS 14, and this unit will be handled as an AV system constituent member thereafter. When the communication data DT ₁ is transmitted, the master unit
Return data RDT ₁ is returned to the slave unit to indicate that T ₁ has been received. Then, the slave unit which is newly connected, for notify the constituent members of the AV system, and transmits the system connection information DT ₂ to the slave unit side. The slave unit that has received the system connection information DT ₂ for acknowledgment, and returns the return data RDT ₂ to the master unit side. Then, after a predetermined time has elapsed, the slave unit transmits a connection confirmation request communication data DT ₁ of (self-reported) to the master unit side again. After the elapse of the predetermined time, the communication data of the connection confirmation request
Sending the DT ₁ in the case of vehicle AV system, ON / OFF of the power supply is dependent on the ON / OFF of the ACC switch, there is a need to verify periodically connected.

As described above, the communication data DT always includes the physical address data PA and the logical address data LA, and the physical address data PA and the logical address data LA are mutually independent data. The communication data DT can be transmitted to any destination.

In the above operation example, an example of communication between the slave unit and the master unit has been described, but communication can be similarly performed between other slave units.

In addition, the format of the communication data DT and the assignment of addresses to each unit
By separately performing the PA and the logical address LA, even if the physical address PA is unknown, if the logical address LA is clearly set, it is possible to connect a new unit, and the new unit can be connected. Communication between the main unit and the already connected unit is possible.

That is, it is assumed that a new slave unit 200- _m is connected to the communication BUS 14, as shown in FIG. In this case, even if the physical address data PA of the slave unit 200- _m is not assumed and the physical address data PA is 101, if the function is the “display function”, it is already registered in the slave unit 200. Since the same function exists with the logical address data LA = 01, the logical address data LA can be accessed, so that the slave unit 200- _m can be connected. This means that A
This will contribute to improving the scalability of the V system.

〔The invention's effect〕

As described above, according to the present invention, it is not necessary to set the address data in a state where the master device and the logical address data or the master device and the logical address data are fixed from the beginning for the number of functions as in the related art. The system can be simplified. Also, even when a new device or function is added, the additional device or additional function can be provided simply by additionally setting the physical address data and the logical address data or only the logical address data, thereby improving the expandability of the AV system. Further, the degree of freedom of connection of the device can be improved.

Further, since the address data includes at least a physical address indicating the transmission source of the communication data and a physical address indicating the transmission destination of the communication data, the transmission of the communication data to the transmission source apparatus is performed. When a reply is sent from the destination device, the source device can be quickly recognized and the reply can be reliably executed.

Furthermore, since at least the physical address indicating the transmission source of the communication data and the physical address indicating the transmission destination of the communication data are included, even when a new device is added in the network, the physical The physical address is immediately recognized in the destination device by the physical address having the source as the source, so that the addition of the new device can be easily and quickly recognized in the destination device. Since the transmission destination device can immediately recognize the transmission source device, the transmission destination device can quickly start processing corresponding to the transmission source device.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention, FIG. 2 is a power supply system diagram of an AV system, FIG. 3 is an overall configuration diagram of the AV system, FIG. 4 is a block diagram of a control network of the AV system, and FIG. FIG. 6 is a block diagram showing a specific example of a connection state between a master unit and a slave unit. FIG. 6 is a block diagram showing another example of a connection state between a master unit and a slave unit. FIG. 7 is an explanatory diagram showing a transfer format of communication data. , FIG. 8 is an explanatory diagram showing the contents of the classification data (major classification), FIG. 9 is an explanatory diagram showing the contents of the classification data (small classification), FIG. 10 is an explanatory diagram showing the basic data format, FIG. Is an explanatory diagram showing an example of a physical address, FIG. 12 is an explanatory diagram showing an example of a physical address, FIG. 13 is an explanatory diagram showing an example of a logical address, and FIG. 14 shows an example of allocation of a physical address and a logical address. Block Diagram Figure 15 is an explanatory view showing an example of a communication operation, FIG. 16 is an illustration of an effect of the present embodiment. ADR… Address data B… Communication BUS CS… Check sum data D… Data DT… Communication data LA, LA _{1 to} LA _n … Logical address data M… Master device PA, PA _{1 to} PA _n … ... physical address data PS ...... physical status data S ₁ to S _n ...... slave device TP ...... classification data 101 ...... car battery 102 ...... ACC switch 103 ...... AV system 200 ...... master units 200 _-1 to 200 _-n ...... Slave unit 1 ...... Cassette tape 2 ...... Antenna 3 ...... CD 4 ...... Multi CD 5 ...... Autochanger 6 ...... Tape deck 7 ...... Tuner 8 ...... CD player 9 ...... Multi CD player 10 … External commander 11… Display 12… Display 13… Input device 14… Communication BUS 15… Selector 16, 16 A… Digital amplifier 17… Speaker 18… Master controller 19… Slave controller 20 ... Slave controller 21 ... Slave controller 22 ... Slave controller 23 ... Slave controller 24 ... Slave controller 25 ... Communication interface IC 26 ... Communication interface IC 27 ... Communication interface IC 28 ... Communication interface IC 29: Communication interface IC 30: Communication interface IC 31: Communication interface IC 32: Communication driver / receiver 33: Communication control IC 34: Controlled part 35: Communication driver / receiver 36: Communication control IC 37 Controlled part 38 Electrical / optical converter 39 Electrical / optical converter

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Shimama 25-1, Nishimachi, Yamada, Kawagoe-shi, Saitama Prefecture Pioneer Corporation Kawagoe Factory (56) References JP-A-63-314096 ) Surveyed field (Int.Cl. ⁷ , DB name) H04L 12/40

Claims (1)

(57) [Claims] 1. A data communication method in a bus-type vehicle-mounted communication network in which one master device and one or more slave devices are connected to the same communication bus, wherein each of the master device and the slave device Assigning a physical address indicating the device, and assigning a logical address indicating a function of each device to each of the master device and the slave device; and address data combining the physical address and the logical address. And a communication step of transmitting data including the generated address data onto the communication bus to perform data communication between the master device and the slave device.
Wherein the address data includes at least the physical address indicating a transmission source of the communication data and the physical address indicating a transmission destination of the communication data. Data communication method in a network.