JPH04326896A - On-vehicle data communication system - Google Patents

Abstract

PURPOSE:To surely set a communication address without taking much time so as to construct easily a network even in the case that plural slave equipments sharing the same controller are connected to a communication bus.. CONSTITUTION:In the on-vehicle communication system 100, one master equipment 101, 101', at least, and plural slave equipments 102-1, 102-2... 102-n are connected to the same communication bus 103, and each slave equipment 102-1, 102-2... 102-n is provided with a storage means 104 to store updatably its own communication address and a connection requesting means 105 to transmit its own connection request information to the master equipment 101, 101' at the time of the start of the network, and the master equipment 101, 101' is provided with a communication address setting means 106 which sets the communication address of the slave equipment when it receives the connection request information, and informs that slave equipment of it.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication system, and more particularly to a data communication system suitable for use in a connection network for a vehicle-mounted AV (audio-visual) system.

0002

2. Description of the Related Art In recent years, in-vehicle audio systems have been evolving from systems that simply 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. An in-vehicle AV system is constructed from a wide variety of elements. For example, audio elements include cassette tape decks, radio tuners, CD (compact disc) players, etc.
Visual elements include a TV (television) tuner, a navigation device, and the like. The audio reproduction signal output from each of these elements is reproduced from a speaker mounted in the vehicle via an amplifier, and the 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, and the control is performed by a controller using a microcomputer.

[0003] In order to operate each of the above elements systematically, it is necessary to control each element in an integrated manner. Therefore, in the in-vehicle AV system, the controllers of each of the above-mentioned elements are connected through a bus-type network, and mutual control data is sent and received via the communication bus that constitutes the network. In this conventional network, when a master device sends communication data to and accesses a slave device, or when a slave device sends data back to the master device, it is necessary to identify or specify each controller. Therefore, each controller is assigned an address (communication address) indicating the controller, and in the conventional communication address assignment method, each controller is assigned a unique communication address.

0004

[Problems to be Solved by the Invention] In the conventional network described above, each controller is assigned a unique communication address. Therefore, it is difficult to connect slave devices having the same functions, such as the same CD player, with the same controller. When a plurality of CD players are connected, there is a problem in that even if an attempt is made to operate one CD player, both CD players end up performing the same operation. To solve this problem, if there are multiple slave devices with the same controller, the user may need to change the settings of a switch, such as a dip switch, provided on each slave device to set the communication address. Therefore, it is necessary to allocate different communication addresses, which is time consuming and difficult to set the communication addresses reliably.

[0005] Therefore, the present invention makes it possible to easily set a communication address and easily construct a network even when a plurality of slave devices having the same controller are connected to a communication bus. The purpose is to provide an in-vehicle data communication system.

[0006]

[Means for Solving the Problems] FIG. 1 is a diagram illustrating the principle of the present invention. The in-vehicle data communication system 100 includes at least one master device 101 (101') and a plurality of slave devices 102-1, 102-2,..., 102-n.
are connected to the same communication bus 103, and each slave device 102-1, 102-2, .
When starting the network, enter your own connection request information to 10
1 (, 101') Connection request means 1 sent to master device
05, and the master device 101 (, 101') is
When receiving the connection request information, the communication address setting means 106 sets the communication address of the slave device to be different from that of other slave devices, and notifies the slave device.

[0007]

[Operation] According to the present invention, a plurality of slave devices 102-
1, 102-2, ..., 102-n each connection requesting means 10
5 transmits its own connection request information to the master device 101 (, 101') when the network is activated. When the communication address setting means 106 receives the connection request information, it sets the communication address of the slave device to be different from that of other slave devices, and notifies the slave device.

[0008] As a result, each slave device 102-1,
Each storage means 104 of 102-2, . . . , 102-n stores its own communication address that has been notified. therefore,
Each slave device 102-1, 102-2,..., 102-
Different communication addresses are set for n.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. Power supply system for AV system In a preferred embodiment, the present invention is applied to a vehicle-mounted AV system. As shown in FIG. 2, the AV device 113
Power is supplied from the car battery 111 via the switch 112. The ACC switch 112 is a switch that is linked to the engine key of the automobile.
By rotating the switch 112 to the position,
Power is supplied to accessories in the car, and
Power is supplied to the V device 113.

Configuration Example of AV System FIG. 3 shows a configuration example of an AV system to which the present invention is applied. In the example of FIG. 3, the audio playback device includes a tape deck 6 that plays back recorded signals from a cassette tape 1, a tuner 7 such as an FM tuner that plays back radio waves received by the antenna 2, and a recorded signal played from each CD of a multi-CD 4A. Multi-CD player 9A including auto changer 5A
and a multi-CD player 9B including an autochanger 5B for reproducing recorded signals from each CD of the multi-CD 4B. As a visual reproduction device, antenna 2
It includes a display 12 that outputs images from a TV tuner (assumed to be built in the tuner 7) that reproduces TV radio waves received by the tuner 7. The external commander 10 includes a keyboard for inputting various operation commands from the outside. The input device 13 can also be incorporated into the external commander 10.

Each of the above devices has a controller for controlling its own operation, and each controller has a communication B.
They are connected to each other via the US 14 to form a bus-type control network. The configuration of this network is shown in FIG. 4, and the details will be described later. On the other hand, the playback signal S1 of the audio playback device is selectively input to the digital amplifier 16 as the playback signal S2 via the selector 15, and the playback signal S2 amplified by a predetermined amount is output from the speaker 17 as the playback signal S3. The digital signal system 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 14.

The control network of the AV system is shown in FIG.
An example of a control network of an AV system is shown. Here, for convenience of explanation, communication BUS1 is shown in FIG.
Each device connected to 4 will be referred to as a "unit" in general terms. As shown in Figure 4, communication B
Each unit is connected in parallel to the US14. One of the units is designated as a "master" in order to collectively control the network, and is designated as a master unit 200. All other remaining units are
slave unit 200-
1 to 200-n.

A master controller 18 built into the master unit 200 is connected to a communication BUS 14 via a communication interface IC 25. In this example,
The master controller 18 is designed to control both the tape deck 6 and the tuner 7. Similarly, each slave controller 18-1 to 18-n built in the slave units 200-1 to 200-n also communicates with B via the communication interface IC25-1 to 25-n.
Connected to US14.

FIG. 5 shows a specific example of the connection state between the master unit 200 and the slave units 200-n. Figure 5
As shown in FIG. 2, master unit 200 and slave unit 200-n are connected by communication BUS14. The communication BUS 14 uses twisted pair wires consisting of two wires. Communication data DT sent and received via communication BUS 14 is sent and received by communication interface IC 25 and communication interface IC 25-n of master unit 200 and slave unit 200-n. The communication interface IC25 is a communication driver/
It is separated into a receiver 32 and a communication control IC 33, and similarly, the communication interface IC 25-n is separated into a communication driver/receiver 35 and a communication control IC 36. Conventionally, these have been provided integrally within one IC. Communication control IC33 is CM
The communication driver/receiver 32 is formed of an OS transistor, and the communication driver/receiver 32 is formed of a bipolar transistor with high current driving ability. The same applies to the communication driver/receiver 35 and communication control IC 36.

[0015] In this way, the communication interface IC2
Regarding 5, by separating the communication control IC 33 and the communication driver/receiver 32, the communication BU
It becomes possible to cope with the change of the transmission medium in S14. For example, in the example of FIG. 5, communication BUS1 is used for differential transmission.
4, a twisted pair wire is used as the communication BUS 14, but as shown in FIG. This can be done without making any changes. Moreover, malfunctions occurring in the master unit 200 are 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 3
In many cases, only the communication driver/receiver 32 needs to be out of order, and it is advantageous in terms of maintenance, as it is easy to restore the status quo by replacing only the communication driver/receiver 32. In particular, in-vehicle AV
In the case of a system, there are many opportunities for noise generated from the engine system of a car to mix in, so this is effective.

[0016] Also, from the viewpoint of IC manufacturing, Bi-C
Rather than using a MOS IC configuration, separating the IC into CMOS transistor and bipolar transistor ICs, which have different manufacturing processes, is easier to manufacture and more cost-effective. Note that although the above explanation has been about the communication interface IC 25, other slave units 2
Communication interface IC25 for 00-1 to 200-n
-1 to 25-n also have communication control ICs.
and communication driver/receiver.

Transmission format of communication data DT Next,
The transmission format of communication data DT used in the present invention will be explained. FIG. 7 shows an example of a transfer format of communication data DT. As shown in FIG. 7, communication data D
T is master address data MA indicating the address of the master unit 200 from the beginning, and slave unit 200-1.
A slave address SA indicating an address of ~200-n,
It consists of message length data N indicating the message length of data D, classification data TP indicating the type of data D, and data D indicating transfer contents.

The structure of the data D varies depending on the content of the communication data DT, that is, the classification data TP, and can be roughly divided into three types of format structures. As shown in Figure 8,
The first format is for connection confirmation, the second format is for keys, display data, etc., and the third format is for checksum C.
This is the format for sending the results of S. Note that in FIG. 8, in the format of keys and display data, the data configurations from physical status PS to logical mode LM are all the same, so illustration is omitted.

The classification data TP is a data area that is placed at the beginning of the communication data DT and represents the type of data D that follows the classification data TP. The classification data TP is composed of major classification data and minor classification data. The major classification data represents the type of data D, as shown in FIG. When the entire classification data TP is 8 bits, the bit allocation is the upper 4 bits.
Bits are assigned. As shown in FIG. 10, the minor classification data is mainly used to identify the format of data D, and the lower 4 bits are assigned to it. For example, if the classification data TP="21H", the upper 4 bits are "2".
Since it is "H", it means that the key data is transferred from the slave unit to the master unit, and the lower 4 bits are "H".
1H'', which means that the key data to be transferred is the remote control data itself.

The physical address data PA is shown in FIGS.
2, each master unit 200 to slave unit 200-1 to 200- on the communication BUS 14
This is a communication address for specifying the communication interface IC 25-1 to 25-n of the master unit 200 and slave units 200-1 to 200-n.
This is the address that indicates. Of this physical address data PA, the physical address data PA that specifies the master unit 200 is always fixed. Physical address data P
Basically, one physical address data PA is assigned to one unit. FIG. 14 shows an example in which physical address data PA is assigned in association with the unit configuration of FIG. 3. In addition, in FIG. 14, the master controller 1
The physical address data PA is also set in 8, but this takes into consideration the case where two functional elements such as the tape deck 6 and the tuner 7 are connected to one controller master controller 18, as in the master unit 200. It is something. In the combination of one controller with one function, slave controllers 18-1, 18-2, 1
As in 8-4 and 18-5, the physical address data PA and the logical address data LA are the same address.

[0021] Physical status data PS is
Master unit 200, slave unit 200-1~
This is status information regarding the unit 200-n, and is data indicating the number of functional addresses (that is, logical address data LA to be described later) that the unit has. The logical address data LA is as shown in FIG.
Master unit 200, slave unit 200-1~
This data indicates the functions of the relevant unit of 200-n (that is, functions such as tuner, tape deck, etc.), and is divided for each function. The number of logical address data LA is equal to the number of functions handled by the controller determined by the physical address data PA, LA1, LA2...
It is not a fixed number because it is added like this. Figure 1
4 shows an example in which logical address data LA is assigned in association with the unit configuration of FIG.

[0022] Talker address data TL indicates the address of the source (speaker) that transmits the communication data DT. The listener address data LN indicates the address of the destination (listener) that receives the communication data DT. Logical status data LS represents the state of the function corresponding to each logical address LA. Logical mode data L
M represents the operating state (mode) of the function corresponding to each logical address. Checksum data CS is data D
This is data for error detection added to improve reliability.

Communication operation In the AV system described above, the master unit 2
00 and the slave units 200-1 to 200-n, the operation when communicating communication data DT for connection confirmation and communication address setting at the time of network startup will be described below. In this network, all slave units 200-1 to 200-n self-report their own units to the master unit 200. The master unit 200 is a slave unit 200-1 to 200
- No active access operation is performed on the n side.

That is, the basic algorithm of the connection confirmation and communication address setting sequence at the time of network activation in the present invention is as follows. 1) The slave controller of the slave unit functions as a connection requesting means, and after detecting power ON, accesses the master unit and requests connection confirmation using a provisional communication address.

2) The master controller of the master unit functions as communication address setting means, and in response to this connection confirmation request, notifies the final address using the provisional communication address. At this time, even if multiple slave devices with the same slave controller are connected to the communication bus, only one slave device has accepted the connection confirmation request, so other slave devices with the same slave controller can , Even if a connection confirmation request is made using the provisional communication address in an attempt to access the master unit after the power is turned on, the connection confirmation request will not be accepted due to the delay in power up. Therefore, only the slave device that has received the connection confirmation request receives the fixed address, stores the notified fixed address in a memory that functions as a storage means, and uses this fixed address for subsequent communication.

3) On the other hand, for the slave device whose connection confirmation request was not accepted, the connection confirmation request is subsequently accepted by the master unit, and the master controller of the master unit notifies the connection confirmation request in advance. A temporary communication address is used to notify a finalized address that is different from the finalized address. As a result, only the slave device receives the fixed address, stores the notified fixed address in a memory functioning as a storage means, and uses this fixed address for subsequent communication.

[0027] In this way, different communication addresses can be assigned to all slave units by utilizing the start-up delay when the power is turned on. This communication sequence is stored as a control program in the controllers that constitute master unit 200 and slave units 200-1 to 200-n. In addition, the slave units 200-1 to 200-n when the power was turned off last time
The connection state of the slave units 200-1 to 200-n shall be stored in a writable memory (RAM) provided in the master unit 200, and each slave unit 200-1 to 200-n shall also store its own fixed communication address in its respective memory. do.

Next, a specific example is shown in FIG. Figure 15 shows
The following is an example of a sequence between two slave units including a multi-CD player and a master unit, when the slave unit accesses to check the connection to its own AV system and set the communication address when starting the network. It is something that Now, in Figure 15,
The multi-CD player 9A, which is a slave unit, issues communication data DT1 and transmits it to the master unit via the communication BUS 14 in order to request connection confirmation (self-report). At this time, the communication data DT1 sets its own physical address data PA to the provisional communication address "1FFH" (H is hex in hexadecimal), the physical address data PA of the destination master unit to "100H", and the own slave unit The logical address data LA=06 indicates that the configuration includes a multi-CD player. The temporary communication address can be set arbitrarily, but for example, "1FFH" for audio equipment, "2FFH" for navigation equipment, "3FFH" for telephone-related equipment, and "3FFH" for facsimile-related equipment. By grouping by function, such as "4FFH", it becomes easy to use this to set communication addresses for each group.

With this communication data DT1, the master unit sets provisional physical address data PA="1FFH".
It is known that the slave unit having the function of logical address data LA="06H", that is, the slave unit having the function of a multi-CD player, is connected to the communication BUS 14. Accordingly, when the communication data DT1 is transmitted, the master unit transmits the communication data DT1.
1 is received, the return data RDT
1 to the slave unit.

Next, the master unit determines whether a slave unit having the function of a multi-CD player is currently connected. In this case, there is still a multi-CD
Since the slave unit with the player function is not connected, the physical address data PA is used as the first slave unit with the multi-CD player function.
="106H" is set and registered as a confirmed communication address. The setting of this confirmed communication address includes, for example, "1H" which is the upper 4 bits of the provisional communication address "1FFH", "0H" indicating that it is the first slave unit, and logical address data indicating the function of the device. LA=“
The lower 4 bits of “06H” are arranged “6H” and “106
Set it like "H".

Accordingly, in order to notify the slave unit of the confirmed communication address, communication data DT2 is issued and transmitted to the slave unit via the communication BUS14. At this time, communication data DT2 sets its own physical address data PA to "100H", sets the physical address data PA of the destination slave unit to provisional communication address "1FFH", and indicates that the number of data to be transferred is 3 in the message length. N=“03H” and address data ADR=“0” indicating the lower 8 bits of the fixed physical address data PA as the fixed communication address of the slave unit.
6H" is added, and checksum data CS is added.

From now on, the master unit will handle the slave unit as a member of the AV system. Accordingly, when the communication data DT2 is transmitted, the slave unit receives the communication data DT2.
Return data RDT2 is sent to indicate that RDT2 has been received.
to the master unit.

Based on this communication data DT2, the slave unit generates a physical address PA="106H" as a fixed communication address, and performs subsequent communication operations using the physical address data PA="106H". The generation of physical address data PA as a fixed communication address is based on "1H" which is the upper 4 bits of provisional communication address "1FFH" and address data ADR="06H".
are arranged to generate "106H".

On the other hand, the slave unit Multi-CD
The player 9B issues communication data DT3 for a connection confirmation request (self-report), but it is not received during the above communication, and after the above communication ends, the communication data DT3 is sent to the master unit via the communication BUS 14. conduct. At this time, the communication data DT3 is issued to the communication BUS 14 in the same manner as the multi-CD player 9A.
Sends to the master unit via. At this time, the communication data DT3 should have its own physical address data PA set to the provisional communication address "1FFH", the physical address data PA of the other party's master unit set to "100H", and its own slave unit configured to include a multi-CD player. is indicated by logical address data LA="06H".

With this communication data DT3, the master unit sets provisional physical address data PA="1FFH".
In this case, the unit with the function of logical address data LA="06H", that is, the function of a multi-CD player, communicates with B.
I know that it is connected to US14. Accordingly, when the communication data DT3 is transmitted, the master unit returns return data RDT3 to the slave unit to indicate that it has received the communication data DT3.

Next, the master unit determines whether a slave unit having the function of logical address data LA="06H", that is, the function of a multi-CD player, is currently connected. In this case, since one slave unit with the multi-CD player function is already connected, the physical address data PA="116H" is confirmed as the second slave unit with the multi-CD player function. Register as an address.

Accordingly, in order to notify the slave unit of the confirmed communication address, communication data DT4 is issued and transmitted to the slave unit via the communication BUS14. At this time, communication data DT4 sets its own physical address data PA to "100H", sets the physical address data PA of the destination slave unit to provisional communication address "1FFH", and indicates that the number of data to be transferred is 3 in the message length. N="03H" and address data ADR="16H" indicating the lower 8 bits of the determined physical address data as the determined communication address of the slave unit.
” is added, and checksum data CS is added.

[0038] From now on, the master unit will handle the slave unit as a member of the AV system. Accordingly, when the communication data DT4 is transmitted, the slave unit receives the communication data DT4.
Return data RDT4 is sent to indicate that RDT4 has been received.
to the master unit.

Based on this communication data DT4, the slave unit generates a physical address PA="116H" as a fixed communication address, and performs subsequent communication operations using the physical address data PA="116H". In the above embodiment, only the case when starting the network was described, but when connecting a new slave unit to an already established network, the same procedure as for setting the communication address of the second slave unit described above can be used. It is possible to set a communication address for the new slave unit.

In the above embodiment, only the case where there is one master unit has been described, but slave units may be divided into groups such as audio equipment, navigation equipment, etc., and provisional communication addresses may be set for each group. If this is done, it is also possible to use a plurality of master units, each of which determines the slave unit to be controlled based on a provisional communication address, and sets the communication address of the slave unit to be controlled.

[0041]

As described above, according to the present invention, the communication address setting means uses the lag in reception of connection request information due to the lag in the start-up of the power supply to set the communication address of a slave device to be different from that of other slave devices. Since the settings are different from each other, even if multiple slave devices with the same function are connected to the communication bus, you can easily set the communication address for each slave device without any trouble and easily establish the network. This has the effect of making it possible to construct.

[Brief explanation of drawings]

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

FIG. 2 is a power supply system diagram of the 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.

FIG. 5 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 a basic data format.

FIG. 9 is a diagram illustrating the contents (major classification) of classification data TP.

FIG. 10 is a diagram illustrating the contents (minor classification) of classification data TP.

FIG. 11 is a diagram illustrating an example (1) of physical addresses.

FIG. 12 is a diagram illustrating an example (2) of physical addresses.

FIG. 13 is a diagram illustrating an example of logical addresses.

FIG. 14 is an explanatory diagram showing an example of allocation of physical addresses and logical addresses.

FIG. 15 is an explanatory diagram showing an example of communication operation.

[Explanation of symbols]

1...Cassette tape 2...Antenna 3...CD 4...Multi-CD 5...Autochanger 6...Tape deck 7...Tuner 9A, 9B...Multi-CD player 10...External commander 11...Display 12...Display 13...Input device 14...Communication BUS 15 ...Selector 16...Digital amplifier 17...Speaker 18...Master controller 18-1 to 18-n...Slave controller 25, 25
-1 to 25-n...Communication interface IC32...Communication driver/receiver 33...Communication control IC 34...Controlled section 35...Communication driver/receiver 36...Communication control IC 37...Controlled section 38...Electronic/optical converter 39... Electrical/optical converter 100...In-vehicle data communication system 101, 101'...Master device 102-1 to 102-n...Slave device 103...Communication bus 104...Storage means 105...Connection request means 106...Communication address setting means 111... Car battery 112...ACC switch 113...AV device 200...Master unit 200-1 to 200-n...Slave unit ADR...Address data B...Communication BUS CS...Checksum data D...Data DS1 to DS2...Connection request information DT...Communication Data LA, LA1 to LAn...Logical address data PA,
PA1 ~PAn...Physical address data PS...Physical status data TP...Classification data

Claims (4)

[Claims] Claim 1: A bus-type in-vehicle data communication system comprising at least one master device and a plurality of slave devices connected to the same communication bus, wherein each slave device is capable of updating its own communication address. and a connection requesting means for transmitting its own connection request information to the master device when the network is activated, and upon receiving the connection request information, the master device transmits the communication address of the slave device. 1. An in-vehicle data communication system comprising communication address setting means for setting a communication address to be different from that of other slave devices and notifying the slave device. 2. The in-vehicle data communication system according to claim 1, wherein each of the slave devices stores a provisional communication address in the storage means before starting up the network. Data communication system. 3. The in-vehicle data communication system according to claim 2, wherein said storage means stores the same provisional communication address for each predetermined group. 4. The in-vehicle data communication system according to claim 2 or 3, wherein the communication address setting means sets the communication address based on the provisional communication address. Communications system.