JP3045326B2 - In-vehicle data communication system - Google Patents

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 as a connection network for an on-vehicle AV (audio visual) system.

[0002]

2. Description of the Related Art In recent years, on-board audio systems have been developed from systems that merely listen to music to systems that include visual elements. Such a system having not only audio but also visual functions is known as an AV system. An in-vehicle AV system is constructed by various elements. For example, audio elements include a cassette tape deck, a radio tuner, a CD (compact disc) player, and the like.
The visual elements include a TV (television) tuner, a navigation device, and the like. 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 for each of the above elements to operate systematically, it is necessary to control each element collectively. 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 the above-described in-vehicle AV system, in order for the master device to transmit and access communication data to the slave device or to return data from the slave device to the master device, the controller of each device must be identified or specified. Must be performed, and an address indicating the controller is assigned to each controller.

Further, in order for the master device to access the slave device, the master device needs to register the addresses of all slave devices on the communication bus. Cannot perform any access, and may not function even if the slave device is physically or electrically connected to the communication bus.

In order to solve this problem, when a master device receives a connection confirmation request from a slave device, the master device issues connection information regarding the other slave devices connected to the communication bus and the master device to the slave device. It is configured to be. Further, since this connection information changes depending on the operation state of each slave device, the slave device transmits its own connection information to the master device at predetermined time intervals, and receives the connection information of each slave device. The master device is configured to transmit connection information of all slave devices and its own connection information to each slave device.

FIG. 29 shows a timing chart for exchanging connection information of a conventional in-vehicle AV system. When the slave device A makes a connection confirmation at time t _1, the master device after the predetermined time Δt transmits the connection information of all slave devices own connection information and current the master device is placed under the control the slave apparatus A . Thereafter, the slave device A checks the connection at predetermined time intervals (for example, every two seconds), and the master device transmits the above-described connection information to the slave device A in one-to-one correspondence.

In parallel with this, the master device determines, for all slave devices, whether or not connection has been confirmed from a slave device within a predetermined time interval (for example, 5 seconds), thereby determining the number of connected slave devices. The type is monitored, and the presence or absence of a dropped slave device or a newly added slave device is checked. For example, assuming that the slave device B that has been connected is disconnected at time t ₂ , the master device determines that there is no connection confirmation from the slave device B at the timing of confirming the number of connected slave devices (time t ₃ ). After that, the slave device B will be treated as if it has been dropped, and will be transmitted after removing the connection information of the slave device B from the connection information to be transmitted next time. Conversely new slave device to the slave device A is connected at time t _1, in the case that has the connection confirmation is to determine the master device that the slave device has not been connected confirmed until then Then, the transmission is performed by adding the connection information of the slave device A to the connection information to be transmitted next time.

[0008]

As described above, in the above-mentioned conventional vehicle-mounted communication bus system, it is necessary to frequently exchange data for connection confirmation. The communication bus is occupied for a long time, and there is a problem that the original data communication cannot be performed efficiently.

Accordingly, an object of the present invention is to provide a vehicle-mounted data communication system capable of performing necessary connection confirmation and efficiently performing data communication.

[0010]

FIG. 1 is a diagram illustrating the principle of the present invention. In the on-vehicle data communication system 100, at least one master device 101 (101 ′) and a plurality of slave devices 102-1 to 102 _{- n} are connected to the same communication bus 10.
3 and the slave devices 102 _{-1 to} 102 _-n
In the first storage means 104 for storing the connection information, the own connection information stored in the first storage means 104 is the same as the previous connection information transmitted to the master device 101 (101 ') last time. A first connection information transmitting unit 105 that transmits first change information indicating whether or not the connection information is present to the master device 101 (, 101 ′), and the master device 101 (, 101 ′) stores second connection information that stores the connection information. and 106, based on the first change information of the slave devices, the connection information stored in the second storage unit 106 the slave device 102 _-1 to 102 _-n
And the second connection information transmitting means 107 for transmitting to the user.

[0011]

The first storage means 104 stores connection information.
The first connection information transmission unit 105 stores the connection information stored in the first storage unit 104 and the previous master device 10.
1 (, 101 ′), the first change information indicating whether or not the own connection information is the same as the connection information of the master device 101 (, 101 ′).
101 ').

[0012] The second storage means 106 stores connection information. Second connection information transmitting means, based on the first change information of the slave devices, some or all of the connection information stored in the second storage unit 106 the slave device 102 _-1 to 1
02 _-n . Therefore, in the in-vehicle data communication system, the master device and the slave device can always know the latest connection status, and only need to transmit the connection information when the connection status changes. It can be performed.

[0013]

Next, a preferred embodiment of the present invention will be described with reference to the drawings. Power system of AV system The present invention is preferably 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 linked to the engine key of the automobile.
By turning to the position of the switch 112,
Power is supplied to the accessories in the car, and A
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 shown in FIG. 3, a tape deck 6 for reproducing a recording signal from the cassette tape 1, a tuner 7 such as an FM for reproducing a radio wave received by the antenna 2, and a CD player 8 for reproducing a recording signal from the CD 3 are used as the audio reproducing apparatus.
And a multi-CD player 9 including an autochanger 5 for reproducing a recording signal from each CD of the multi-CD 4. As the visual reproduction device, a TV tuner (supposed to be built in the tuner 7) for reproducing TV electric waves received by the antenna 2 or a still image recorded when the CD player 8 is a CD-ROM. CD
A display 12 for outputting images via the player 8 is included. A typical example of using a CD-ROM is a navigation device. The external commander 10 includes a keyboard for inputting various operation commands from outside. The input device 13 can be incorporated in the external commander 10.

Each of the above devices has a controller for controlling its own operation.
They are connected to each other via US14 to form a bus-type control network. The configuration of this network is shown in FIG. 3, and the details will be described later. On the other hand, the reproduced signal S ₁ of the audio reproducing apparatus is selectively input to the digital amplifier 16 as the reproduced signal S ₂ via the selector 15, and after being amplified by a predetermined amount, the reproduced signal S ₂ is output from the speaker 17. It is emitted as S _3. 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 14.

[0016] control network 4 of an AV system, an example of a control network of the AV system.
Here, for convenience of explanation, in FIG.
Each device connected to 4 is referred to as a “unit” as a general expression. As shown in FIG.
Each unit is connected to US14 in parallel. One of the units is referred to as a “master” in order to control the network in general, and this is indicated by a master unit 200. The other remaining units are all "slaves" and these are
_-1 to 200 _-n .

The master controller 18 built in the master unit 200 is connected to the communication BUS 14 via the communication interface IC 25. In this example,
The master controller 18 also controls the tape deck 6 and the tuner 7. Similarly, the slave controllers 18 _-1 to 18 _-n built in the slave units 200 _-1 to 200 _-n are also connected to the communication BUS 14 via the communication interface ICs 25 _{-1 to} 25 _-n .

FIG. 5 shows a specific example of a connection state between the master unit 200 and the slave units 200- _n . As shown in FIG. 5, the master unit 200 and the slave unit 200- _n are connected by the communication BUS14. The communication BUS 14 uses a twisted pair line composed of two lines. Communication data DT transmitted and received via the communication BUS 14 is transmitted and received by the communication interface IC 25 and the communication interface IC 31 of the master unit 200 and the slave unit 200- _n . The communication interface IC 25 includes a communication driver / receiver I
C32 and communication control IC33,
Similarly, the communication interface IC 31 includes a communication driver /
It is separated into a receiver IC 35 and a communication control IC 36. In this regard, heretofore, the IC has conventionally been provided integrally in one IC. The communication control IC 33 is formed of a CMOS transistor, and includes a communication driver / receiver IC 32
Are formed of bipolar transistors having high current driving capability. The same applies to the communication driver / receiver IC 35 and the communication control IC 36.

Thus, the communication interface IC2
With regard to 5, the communication control IC 33 and the communication driver / receiver IC 32 are separated so that it is 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 S14, as shown in FIG. 6, when an optical communication cable 40 is used as the communication BUS 14, another configuration is obtained by using an electro-optical converter 38 instead of the communication driver / receiver IC 32. We can respond without changing. Also, the master unit 20
The operation failure occurring at 0 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, only the communication driver / receiver IC 32 often fails. It is advantageous for maintenance, for example, by replacing the. In particular, in the case of an in-vehicle AV system, noise generated from the engine system of the automobile is often mixed, which is effective.

From the viewpoint of IC manufacturing, Bi-C
Rather than having a MOS IC configuration, the CMOS transistor and bipolar transistor I
Separation into C facilitates production and is advantageous in terms of cost. The above description is based on the communication interface I.
Although C25 has been described, other slave units 20
Communication interface IC 25 _-1 to 2 of 0 _-1 to 200 _-n
5 _n is similarly separated into a communication control IC and a communication driver / receiver IC.

The transmission format of the communication data DT will be described transmission format of the communication data DT to be used in the present invention. FIG. 7 shows an example of a transfer format of the communication data DT. As shown in FIG. 7, the communication data DT includes master address data MA indicating the address of the master unit 200 and the slave unit 20 from the top.
Slave address S indicating an address from 0 _-1 to 200 _-n
A, 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 differs depending on the contents of the communication data DT, that is, the classification data TP, and is roughly classified into three types of format structures. As shown in FIG. 8, the first format is a format for confirming connection, the second format is a format for keys and display data, and the third format is a format for transmitting the result of the checksum CS. It is. In FIG. 8, the format of the key and the display data is the same from the physical status PS to the logical mode LM in the data configuration, so that the illustration is omitted.

The classification data TP is a data area arranged at the head of the communication data DT and representing 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 large classification data indicates the type of the data D as shown in FIG. If the entire classification data TP is 8 bits, the bit allocation
Bits are allocated. As shown in FIG. 10, the small classification data is mainly used for identifying the format of the data D, and the lower 4 bits are allocated. For example, when the classification data TP = “21H”, the upper 4 bits are “2”.
Since it is "H", it means that key data is transferred from the slave unit to the master unit, and since the lower 4 bits are "1H", the transferred key data is the remote control data itself.

The physical address data PA is shown in FIGS.
As shown in FIG. 2, the master unit 20 is a communication address for specifying the communication interface ICs 25 _{-1 to} 25 _-n of each of the master unit 200 to the slave units 200 _-1 to 200 _-n on the communication BUS 14.
0 is an address indicating 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. Basically, one unit of the physical address data PA is assigned one physical address data PA. FIG. 14 shows an example in which physical address data PA is allocated in association with the unit configuration in FIG. In FIG. 14, the physical address data PA is also set in the master controller 18. This is because the two functional elements of the tape deck 6 and the tuner 7 are provided in one controller master controller 18 like the master unit 200. Is connected. 1
In the combination of one controller and one function, as in the slave controllers _18-1 , _18-2 , _18-5 ,
The physical address data PA and the logical address data LA have the same address.

The physical status data PS is
Master unit 200, slave unit 200 _-1 to 2
00- _n is status information on the unit,
This data indicates the number of function addresses (that is, logical address data LA described later) of the unit. As shown in FIG. 13, the logical address data LA includes a master unit 200 and slave units 200 _-1 to 200 _-1.
-n is data indicating a function of the unit (that is, a function of a tuner, a tape deck, or the like), and is assigned to each function. The number of the logical address data LA is not a fixed number because the number of functions assigned to the controller determined by the physical address data PA, such as LA ₁ , LA _2, ... FIG. 14 shows an example in which logical address data LA is allocated in association with the unit configuration of FIG.

The talker address data TL indicates an address of a transmission source (speaker) for transmitting the communication data DT. The listener address data LN is the communication data DT
Indicates the address of the transmission destination (listener) for receiving. The logical status data LS indicates a state of a function corresponding to each logical address 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.

Connection Information Transfer Operation In the AV system described above, the master unit 2
An operation of transferring connection information between the slave unit 200 and the slave units 200 _-1 to 200 _-n will be described. In this AV system, the slave unit 20 is provided at predetermined time intervals.
It is assumed that the connection information of the own unit is self-reported (periodic communication) from the 0 _-1 to 200 _-n side to the master unit 200.

FIG. 15 is a timing chart for exchanging connection information of the on-vehicle AV system according to the present invention.
The new slave device A makes a connection confirmation at time t _1. Thereafter, the slave device A checks the connection every predetermined time interval (for example, 2 seconds), but the master device stores all the connection confirmations performed within the predetermined time interval (for example, 5 seconds). At the timing when the connection information is transmitted (time t ₂ ), the connection information is transmitted to all the slave devices including the slave device A for the first time.

In parallel with this, the master device determines whether or not the connection from the slave device has been confirmed within a predetermined time interval (for example, 5 seconds) for all the slave devices. The type is monitored, and a lost slave device or a newly added slave device is checked. For example, if the previously connected slave device B is dropped at time t ₃ , the master device determines that there is no connection confirmation from the slave device B at the timing of checking the number of connected slave devices (time t ₂ ). Knowing that, the slave device B is determined to have dropped out, and then transmits the next connection information at the next transmission time (time t ₂ ), excluding the connection information for the slave device B. Conversely new slave device to the slave device A is connected at time t _1, in the case that has the connection confirmation is to determine the master device that the slave device has not been connected confirmed until then Then, at the timing of transmitting the next connection information (time t ₂ ), the connection information on the slave device A is added and transmitted.

Hereinafter, the transfer sequence of the present invention will be described in detail with reference to FIGS. The transfer sequence of the connection information in the present invention is roughly divided into a communication sequence at the time of regular communication, and a communication sequence when the number or type of connected slave units changes.

(1) Periodic Communication At the time of the periodic communication, the basic algorithm at the time of the periodic communication is roughly classified into a communication sequence when the connection information of the slave unit does not change, and a communication when the connection information of the slave unit changes. It consists of a sequence and a communication sequence when a change occurs in the connection information of the master unit.

A) The basic algorithm of the communication sequence when there is no change in the connection information of the slave unit is as follows. A1) The slave controller of the slave unit functions as first connection information transmitting means, transfers the classification data TP including the first change information as communication data, and does not transfer its own connection information.

A2) The master controller, which has received the first change information, knows that there is no change in the connection information of the slave unit, and functions as a second connection information transmitting means.
The classification data TP including the change information is transmitted to all slave units. B) The basic algorithm of the communication sequence when a change occurs in the connection information of the slave unit is as follows.

B1) The slave controller of the slave unit functions as first connection information transmitting means, transmits the classification data TP including the first change information, and transmits the changed own connection information as communication data. B2) The master controller that has received the first change information and the connection information of the slave unit stores the connection information of the slave unit in the memory as the second storage unit, and functions as the second connection information transmission unit, and functions as the second connection information transmission unit. The classification data TP including the information, its own connection information, and the connection information of all the slave units stored in the storage means are transmitted to all the slave units.

C) The basic algorithm of the communication sequence when the connection information of the master unit changes is as follows. C1) The master controller of the master unit transmits the classification data TP including the second change information, and transfers its own connection information after the change as communication data.

(2) Number or type of connected slave units
Basically the algorithm of a communication sequence when a change is changed when connected slave unit number or type caused occurs broadly includes a communication sequence when the slave unit is dropped, when a slave unit is connected to the new And a communication sequence. D) The basic algorithm of the communication sequence when the slave unit drops out is as follows.

D1) If the master unit of the master unit does not perform regular communication from the slave unit that has received the connection information last time, it determines that the slave unit has dropped out, and as a second connection information transmitting means. Currently, the classification data TP including the second change information, the connection information of its own stored in the memory as the second storage means, and the connection information of all slave units other than the dropped slave unit are currently connected. Send to all slave units.

E) The basic algorithm of the communication sequence when a slave unit is newly connected is as follows. E1) The slave controller of the slave unit functions as first connection information transmitting means, transmits the classification data TP including the first change information, and transfers its own connection information as communication data.

E2) Upon receiving the first change information and the slave unit connection information, the master controller newly stores the slave unit connection information in the memory as the second storage unit and functions as the second connection information transmission unit. Then, the classification data TP including the second change information, the connection information of the self, and the connection information of all the slave units including the newly connected slave unit stored in the storage means are transmitted to all the slave units.

These sequences correspond to the master unit 20
0 and the slave units 200 _-1 to 200 _-n are stored as control programs in the controllers. (I) Detailed operation at the time of periodic communication Here, referring to the communication sequence of FIG. 16 to FIG.
The connection information transfer process in the regular communication will be described in detail.

(I) When there is no change in the connection information of the slave unit This sequence is for the case where there is no change in the connection information of the slave unit. Only the data corresponding to the first change information is transferred, This is a case where the connection information of the unit is not transferred. Now, in FIG. 16, the slave unit (PA = “124H”) issues communication data DT ₁ to transfer its own connection information and
Is transmitted to the master unit via. At this time, the communication data DT ₁ has its own physical address data PA = “1”.
24H ", the physical address PA of the transfer destination master unit =" 100H ", the number of data to be transferred is two, the message length N =" 02H ", and the classification data indicates that the connection information is to be transferred. Upper 4 bits of TP are set to “0H”
, The lower 4 bits of the classification data TP are set to “0H” to indicate that there is no change in the connection information transferred as the first change information, and the checksum data CS is added.

Thus, the master unit issues return data RDT1 indicating that the checksum is correct and returns it to the slave unit to indicate that the connection information has been received. Further, the master unit issues communication data DT ₂ corresponding to the second change information indicating no change to each slave unit at a predetermined connection information transfer timing in order to notify that the connection state of the entire system has not changed. To each slave unit. In this case, communication data D is transmitted to all slave units.
Although to issue T _2, for simplicity of description, only the case of transmitting the communication data DT ₂ in the aforementioned slave unit. At this time, the communication data DT ₂ is
The own physical address data PA = “100H”, and the physical address PA = “124” of the transfer destination slave unit.
H, indicating that the number of data to be transferred is two by a message length N = “02H”, indicating that the connection information is to be transferred by setting the upper 4 bits of the classification data TP to “0H”, No change in the connection information transferred as the first change information is indicated by setting the lower 4 bits of the classification data TP to “0H”, and the checksum data CS is added.

As a result, the slave unit issues return data RDT ₂ indicating that the checksum is correct and returns it to the master unit to indicate that the connection information has been received. By the communication operation as described above, the master unit and each slave unit continue to hold the connection information held up to now without updating, and perform data communication based on the held connection information. .

(Ii) When the connection information of the slave unit has changed. —Part 1— This sequence is for the case where the connection information of the slave unit has changed, and the connection information of the master unit has changed. This is a case in which connection information of all slave units is transferred after receiving communication data from the slave units. The aforementioned slave unit (PA = “124
H ”), the connection information may be changed, for example, when the display (logical address data LA =
If “01H”) fails and becomes inoperable, and only the function of the external commander (logical address data LA = “09H”) alone operates, the slave unit transmits the changed connection information to the master unit. 17, the communication data DT ₃ is issued and transmitted to the master unit via the communication bus 14 as shown in FIG.
At this time, the communication data DT ₃ has its own physical address data PA = “124H”, the physical address PA of the transfer destination master unit = “100H”, and the message length N = 4 that the number of data to be transferred is four. This is indicated by “04H”, indicating that the connection information is to be transferred by setting the upper 4 bits of the classification data TP to “0H”, and indicating that the connection information to be transferred has changed by the lower 4 bits of the classification data TP. “1
"H" to indicate that the slave unit has one function by setting the upper 4 bits of the physical status data PS to "1H", indicating that the function currently possessed is an external commander. Logical address data LA = "09H" is shown, and checksum data CS is added.

As a result, the master unit issues return data RDT ₃ to indicate that the connection information has been received, and returns it to the slave unit. The master unit knows that there is a change in the connection information of the slave unit since the lower 4 bits of the classification data TP is "IH", by issuing a communication data DT ₄ including the second information indicating the presence of change Transfer to each slave unit via the communication bus. Here, a description will be given only when transmitting the communication data DT ₄ in the aforementioned slave unit for simplicity of explanation.

At this time, the communication data DT ₄ has its own physical address data PA = “100H”, the physical address PA of the destination slave unit = “124H”, and the message length N corresponding to the number of data to be transferred. In addition, the transfer of connection information is indicated by setting the upper 4 bits of the classification data TP to “0H”, and the lower 4 bits of the classification data TP are set to “1” to indicate that the connection information to be transferred has changed.
H ”to indicate the connection information MS of the master unit.
And connection information SL _{1 to} SL _n of all slave units, and checksum data CS.

In this case, the connection information MS of the master unit indicates that the master unit has three functions, the upper four of the physical status data PS.
By setting the bit to “3H”, the first logical address data LA ₁ = “00” indicates that the current function is the master, the cassette tape deck, and the tuner, respectively.
H ”, the second logical address data LA ₂ =“ 03 ”
H ”, third logical address data LA ₃ =“ 07H ”
Is shown.

[0048] Further, the connection information of the aforementioned slave units (physical address data PA = "124H") is transmitted as the connection information SL _1. At this time, the connection information SL ₁
Indicates that the lower 8 bits = "24H" of the physical address data PA of the slave unit is connection information of the slave unit, and indicates that the slave unit has only one function. The upper four bits are set to “1H”, and the logical address data LA = “09H” indicates that the current function is an external commander. The same applies to the connection information SL ₂ to SL _n of other slave units.

As a result, the slave unit issues return data RDT ₄ to indicate that the communication data DT ₄ has been received, and returns it to the master unit. By the above-described communication operation, each slave unit updates the communication information held so far, and performs the subsequent communication operation based on the new connection information.

(Iii) When there is a change in the connection information of the slave unit—part 2—This sequence is when there is a change in the connection information of the slave unit, and the master unit has a change in the connection information. In this case, only the connection information of the slave unit is transferred to all slave units. If a situation occurs that changes the connection information of the slave unit described above, for example, as described above (see the description of FIG. 17), and if the display fails and becomes inoperable, the slave unit: for transferring the connection information after the change to the master unit, the communication data DT ₅ as shown in FIG. 18
Is transmitted to the master unit via the communication bus 14.

As a result, the master unit issues return data RDT ₅ to indicate that the connection information has been received, and returns it to the slave unit. Since the lower 4 bits of the classification data TP are “1H”, the master unit knows that the connection information of the slave unit has changed, and issues the communication data DT ₆ including the second information indicating the change. Transfer to each slave unit via the communication bus. Here, for simplification of description, only the case where the communication data DT ₆ is transmitted to the above-described slave unit will be described.

At this time, the communication data DT ₆ has its own physical address data PA = “100H”, the physical address PA of the slave unit of the transfer destination = “124H”, and the number of data to be transferred is five. Message length N =
"05H" indicates that the transfer of the connection information is indicated by setting the upper 4 bits of the classification data TP to "0H", and indicates that the connection information to be transferred has changed. lower 4 bits indicated by the "IH", adds the connection information SL ₁ of there slave unit of change in the connection information, adds the check sum data CS.

In this case, the connection information SL ₁ is the lower 8 bits of the physical address data PA of the slave unit.
Bit = “24H” indicates the connection information of the slave unit, and indicates that the slave unit has only one function.
Are set to “1H”, and the logical address data LA = “09H” indicates that the current function is an external commander.

As a result, the slave unit issues return data RDT ₆ to indicate that the communication data DT ₆ has been received, and returns it to the master unit. By the communication operation as described above, each slave unit updates only the newly notified part of the connection information held so far, and the subsequent communication operation is performed based on the new connection information. .

According to this method, the master unit does not need to transmit all the connection information, and suffices to transmit only the connection information of the slave unit whose connection information has changed, so that the master unit occupies the communication bus. The time can be further reduced. (Iv) When the connection information of the master unit changes
-Part 1- This sequence is for the case where there is a change in the connection information of the master unit, and in the case of transferring the changed connection information of itself and the connection information of all the slave units.
The master unit transfers the connection information after the change to all the slave units, and as shown in FIG.
To transmit to the master unit via the communication bus 14 by issuing T _7. At this time, the communication data DT ₇ sets its own physical address data PA = “100H”, sets the physical address PA of the transfer destination slave unit = “124H”, and adds a message length N corresponding to the number of data to be transferred. The transfer of connection information is indicated by setting the upper 4 bits of the classification data TP to “0H”, and the lower 4 bits of the classification data TP are indicated by “1” to indicate that the connection information to be transferred has changed.
H ”to indicate the connection information MS of the master unit.
And connection information SL _{1 to} SL _n of all slave units, and checksum data CS.

In this case, the connection information MS of the master unit indicates that the connection information of the master unit has been changed by, for example, the lower 8 bits = “00H” of the physical address data PA of the master unit. By setting the upper 4 bits of the physical status data PS to “2H”, it is indicated that the tuner function of the master unit having two functions has failed and the current function has two functions. The first logical address data LA ₁ = “00H” and the second logical address data LA
₂ = “03H”.

Further, in the same manner as described above,
Unit connection information SL₁~ SL _nIs added.
As a result, the slave unit transmits the communication data DT₇
Return data RDT to indicate that₇To
Issue and reply to master unit. Like above
Communication, each slave unit keeps
Update the connection information of the master unit that was
Communication operation with the master unit is based on the new connection information
Will be performed.

(V) When there is a change in the connection information of the master unit—part 2—This sequence is when there is a change in the connection information of the master unit, and the own connection information after the change is transferred. However, the connection information of all the slave units is not transferred. In order to transfer the changed connection information to all the slave units, the master unit issues communication data DT ₈ and transmits it to the master unit via the communication bus 14 as shown in FIG. At this time, the communication data DT ₈ is
The own physical address data PA = “100H”, and the physical address PA = “124” of the transfer destination slave unit.
H, indicating that the number of data to be transferred is 6 by a message length N = “06H”, indicating that the connection information is to be transferred by setting the upper 4 bits of the classification data TP to “0H”, The change of the connection information to be transferred is indicated by setting the lower 4 bits of the classification data TP to “1H”, the connection information MS of the master unit is added, and the checksum data CS is added.

In this case, the connection information MS of the master unit indicates that the connection information of the master unit has been changed by, for example, the lower 8 bits = "00H" of the physical address data PA of the master unit. The upper four bits of the physical status data PS are set to "2H" to indicate that the function of the tuner of the master unit having the three functions has failed and that the current function has two functions. The fact that the disc is a cassette tape deck is indicated by setting the first logical address data LA ₁ = “00H” and the second logical address data LA ₂ = “03H”.

Thus, the slave unit issues return data RDT ₈ to indicate that the communication data DT ₈ has been received, and returns it to the master unit. With the above communication operation, each slave unit updates only the connection information of the master unit that has been held up to that point, and the subsequent communication operation with the master unit is performed based on the new connection information.

(II) Change to the number or type of slave units
Detailed Operation in Case of Change of Connection Next, with reference to FIGS. 21 to 25, a connection information transfer process in the case where the number or type of connected slave units has changed will be described in detail. i) When the slave unit is dropped. Now, assuming that n slave units 200 _-1 to 200 _-n are connected to the communication bus as shown in FIG.
Normally, communication data DT ₉ as shown in FIG. 23 is transmitted to all slave units as connection information. At this time, the communication data DT ₉ contains its own physical address data P
A = “100H”, the physical address PA of the slave unit of the transfer destination = “124H”, the message length N corresponding to the number of data to be transferred is added, and the transfer of connection information is indicated by the upper 4 By setting the bit to “0H”, the connection information to be transferred is changed by setting the lower 4 bits of the classification data TP to “1H” to indicate the connection information MS of the master unit and all slave units. Connection information SL _{1 to} SL _n−1 and SL _n of
Checksum data CS is added.

Thus, the slave unit issues return data RDT ₉ to indicate that the communication data DT ₉ has been received, and returns it to the master unit. Thereafter, as shown in FIG. 22, the slave unit 200- _n-1 is dropped due to, for example, an abnormal operation of the slave controller, and the regular communication from the slave unit 200- _n-1 is performed after the previous regular communication ends. If not performed within the time, the master unit compares the slave unit 200 _-n-1 with the previously stored connection information.
There deemed to fall off from the communication bus, to transmit the total slave unit issues a communication data DT ₁₀ as a change in the connection status has occurred (see FIG. 23). At this time, the communication data DT ₁₀ has its own physical address data PA = “1”.
00H ", for example, the physical address PA of the slave unit of the transfer destination is set to" 124H ", and a message length N corresponding to the number of data to be transferred is added. "0H" indicates that the connection information to be transferred has changed by setting the lower 4 bits of the classification data TP to "1H",
Master unit connection information MS and all slave unit connection information SL _{1 to} SL _n (however, connection information SL
_n-1 ) and checksum data CS.

[0063] Thus the slave unit, to indicate that it has received the communication data DT _10, by issuing a return data RDT _10, replies to the master unit. ii) When a slave unit is newly connected. Now, assuming that n slave units 200 _-1 to 200 _-n are connected to the communication bus as shown in FIG.
Typically, the communication data DT ₁₁ as shown in FIG. 25 is transmitted individually for all slave unit as connection information. At this time, the communication data DT ₁₁ has its own physical address data PA = “100H”, for example, the physical address PA = “124H” of the transfer destination slave unit, and adds a message length N corresponding to the number of data to be transferred. The transfer of connection information is indicated by setting the upper 4 bits of the classification data TP to “0H”, and the transfer of connection information is not changed by setting the lower 4 bits of the classification data TP to “0H”. shows, adds connection information SL ₁ to SL _n connection information MS and all slave units in the master unit, adds a checksum data CS.

As a result, the slave unit issues return data RDT ₁₁ to indicate that the communication data DT ₁₁ has been received, and returns it to the master unit. Thereafter, for example, as shown in FIG.
_Assuming that 00- _NEW is newly connected to the communication bus and that there is a connection confirmation from the slave unit 200- _NEW , the master unit compares the slave unit 200- _NEW with the previously stored connection information, and determines that the newly connected to the communication bus to transmit the total slave unit issues a communication data DT ₁₂ as a change in the connection status has occurred (see FIG. 25). At this time, the communication data DT ₁₂ has its own physical address data PA = “100”.
H ", for example, the physical address PA of the slave unit of the transfer destination is set to" 124H ", and a message length N corresponding to the number of data to be transferred is added. "0H" indicates that there is a change in the connection information to be transferred by indicating the lower 4 bits of the classification data TP by "1H", and indicates the connection information MS of the master unit and the connection of all the slave units. adds information SL ₁ to SL _n and connection information SL _nEW of the newly connected slave unit 200 _-NEW, adds a checksum data CS.

[0065] Thus the slave unit, to indicate that it has received the communication data DT _12, by issuing a return data RDT _10, replies to the master unit. In this way, all the slave units know that the slave unit 200- _NEW is newly connected to the communication bus, and
The communication operation can be performed mutually. In the above description, the number of slave units changes, but if the number of slave units does not change and only the type of slave unit changes, one of the slave units is dropped and a new slave unit is added. Since the connection has been made, the above-described process of dropout and new connection is performed.

Other Embodiments In the above embodiments, the case where connection information is individually transferred to each slave unit has been described. However, the case where connection information is simultaneously transferred to all slave units or a plurality of predetermined slave units is described. Another embodiment will be described in detail. In Figure 26, the communication data DT ₁₃ includes a format for sending simultaneously connection information to a plurality of slave units by the master unit selects, such communication data hereinafter referred to broadcast data. In this case, it is assumed that the physical address data PA representing each slave unit is represented by 12 bits.

For example, if the upper 4 bits of all 12 bits of the physical address data PA of all the slave units are all “1H”, the broadcast data of the master unit contains the physical address of the slave unit of the receiving destination. The connection information is transmitted as address data PA = "1FFH". As a result, each slave unit determines whether or not the upper 4 bits are equal using the lower 8 bits of the physical address data PA = “FFH” as the mask data. In this case, since all the slave units recognize that the upper 4 bits are equal, all the slave units receive the connection information.

Therefore, the master unit can transmit the same connection information to all the slave units by one transmission, and the occupation time of the communication bus can be further reduced. After this, each slave unit
Return the return data indicating that the connection information has been received. In the above-described embodiment, the connection information is transmitted to all the slave units. However, if a plurality of slave units having different upper 4 bits of the physical address data PA are connected to the same communication bus, any The connection information can be transmitted at the same time only to the slave units constituting the slave unit group in which the upper 4 bits of the physical address data PA are the same.

For example, as shown in FIG. 27, the first group (A
V group), the upper 4 bits of the physical address data PA are “1H”, the second group (telephone group) has the upper 4 bits of the physical address data PA “2H”, and the third group (navigation group) is the physical address data PA. When the upper 4 bits of the physical address data PA are “4H” and the upper 4 bits of the fourth group (FAX group) are “4H” in the broadcast data of the master unit, the physical address data PA If the connection information is transmitted as "2FFH", it is possible to simultaneously transmit the connection information only to the slave units belonging to the second group, the telephone group.

In each of the above embodiments, the return data is returned after receiving the connection information. However, in a system with high communication reliability, the return data can be omitted. Furthermore, in each of the above embodiments, only one master unit has been described. However, the present invention can be applied to a case where there are a plurality of master units. In this case, as shown in FIG. 28, address setting is also performed for each controller of the master unit to specify which master unit is the communication operation or which master unit is the communication operation. There is a need to.

[0071]

According to the present invention, the first connection information transmitting means of the slave device has the same connection information stored in the first storage device and its own connection information previously transmitted to the master device. The first change information indicating whether or not there is any information is transmitted to the master device, and the second connection information transmitting means of the master device stores the connection information stored in the second storage means based on the first change information of each slave device. Is transmitted to the slave device, the master device and the slave device can always know the latest connection state based on the latest connection information, and the communication bus is occupied for transmitting the connection information. And the original data communication can be performed efficiently.

[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 the AV system.

FIG. 3 is an overall configuration diagram of an 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 an explanatory diagram of the contents (major classification) of the classification data TP.

FIG. 10 is an explanatory diagram of contents (small classification) of classification data TP.

FIG. 11 is an explanatory diagram of an example (1) of a physical address.

FIG. 12 is an explanatory diagram of an example (2) of a physical address.

FIG. 13 is an explanatory diagram of an example of a logical address.

FIG. 14 is a block diagram illustrating an example of assignment of physical addresses and logical addresses.

FIG. 15 is a timing chart of data communication of the present invention.

FIG. 16 is an explanatory diagram (1) illustrating an example of a communication operation;

FIG. 17 is an explanatory diagram (2) illustrating an example of a communication operation;

FIG. 18 is an explanatory diagram (3) illustrating an example of a communication operation;

FIG. 19 is an explanatory diagram (4) illustrating an example of a communication operation;

FIG. 20 is an explanatory diagram (5) illustrating an example of a communication operation;

FIG. 21 is an explanatory diagram (1) of a connection state of the communication system.

FIG. 22 is an explanatory diagram (2) of a connection state of the communication system.

FIG. 23 is an explanatory diagram (6) showing an example of a communication operation (when dropped out).
It is.

FIG. 24 is an explanatory diagram (3) of a connection state of the communication system.

FIG. 25 is an explanatory diagram (7) illustrating an example of a communication operation (at the time of new connection);

FIG. 26 is an explanatory diagram (8) (broadcast communication) illustrating an example of communication operation;

FIG. 27 is an explanatory diagram (4) of the connection state of the communication system.

FIG. 28 is an explanatory diagram (5) of the connection state of the communication system.

FIG. 29 is a timing chart of the conventional data communication.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 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, 16A ... digital amplifier 17 ... speaker 18 ... master controller 18 _-1 ~ 18 _-n ... slave controller 25 ... communication interface IC 32 ... communication driver / receiver IC 33 ... communication control IC 34 ... the controller 35 ... communication driver / receiver IC 36 ... communication control IC 37 ... the controller 38 ... electric / optical converter 39 ... electric / optical converter 100 ... vehicle data communication system 101 and 101 ... master device 102 _-2 to 102 _{- n} ... Slave device 1 03 communication bus 104 first storage unit 105 first connection information transmission unit 106 second storage unit 107 second connection information transmission unit 200 master unit 200 _-1 to 200 _-n 200 _NEW slave unit ADR address data B ... communication BUS CS ... checksum data D ... data DT ... communication data LA, LA ₁ ~LA _n ... logical address data PA, PA ₁ ~PA _n ... physical address data PS ... physical status data TP ... classification data

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hiroshi Shimoma 25-1, Nishimachi, Yamada, Kawagoe-shi, Saitama Prefecture Pioneer Corporation Kawagoe Factory (56) References JP-A-63-215239 (JP, A) 63-284944 (JP, A) JP-A-2-2279 (JP, A) JP-A 64-67661 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12 / 28

Claims (9)

(57) [Claims] 1. A bus type vehicle-mounted data communication system in which at least one master device and a plurality of slave devices are connected to the same communication bus, wherein the slave device stores first connection means for storing connection information; The first
First connection information transmitting means for transmitting to the master device first change information indicating whether or not its own connection information stored in the storage means is the same as its own connection information transmitted to the master device last time; The master device transmits the connection information stored in the second storage device to the slave device based on the first change information of each slave device. And a second connection information transmitting means. 2. The in-vehicle data communication system according to claim 1, wherein said first connection information transmitting means is configured to determine whether said own connection information is not the same as said last transmitted connection information. Along with the first change information, the first
An in-vehicle data communication system, wherein the self-connection information stored in the storage means is transmitted to the master device. 3. The in-vehicle data communication system according to claim 1, wherein the second connection information transmitting unit has already transmitted the connection information stored in the second storage unit to the slave device. An in-vehicle data communication system, wherein second change information indicating whether or not the information is the same as connection information is transmitted to the slave device. 4. The in-vehicle data communication system according to claim 3, wherein when transmitting the second change information, the second change information is connected to the own connection information stored in the second storage means and the communication bus. An on-vehicle data communication system, wherein at least one of connection information of a slave device is transmitted to the slave device. 5. The in-vehicle data communication system according to claim 1, wherein the second connection information transmitting unit changes a total number or types of slave devices connected to the communication bus. Transmitting the connection information stored in the second storage means to the slave device when detecting that there has been an error. 6. The in-vehicle data communication system according to claim 3, wherein said second connection information transmitting means is capable of simultaneous reception by a plurality of slave devices connected to said communication bus. Transmitting at least the second change information of the connection information and the second change information to the in-vehicle data communication system. 7. The in-vehicle data communication system according to claim 3, wherein said second connection information transmitting means is a predetermined one of a plurality of slave devices connected to said communication bus. Wherein at least the second change information of the connection information and the second change information is transmitted only to slave devices belonging to the group of. 8. The in-vehicle data communication system according to claim 1, wherein the first connection information transmitting unit transmits at least the first change information to the master device at predetermined time intervals. An in-vehicle data communication system for transmitting. 9. The in-vehicle data communication system according to claim 3, wherein said second connection information transmitting means transmits at least said second change information to said slave device at predetermined time intervals. An in-vehicle data communication system for transmitting.