JPH10200557A - Data transmission equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manage which device each device performs synchronous communication with in the case of communication by using a parallel interface by holding a flag that shows the input-output of synchronous communication data and a node, etc., of a device that is an object of the input-output of the synchronous communication data. SOLUTION: For instance, a device A requests a device B 102 to transfer synchronous communication data. When the device B 102 receives a transfer request for the synchronous communication data from the terminal A 101, first, it acquires a channel and a band for synchronous communication from a device D 104 that is a bus manager. Later, it retrieves a register whose flag part shows an unconnected state. The flag part of the register that is selected as an empty register is changed from the state that shows an unconnectedness to a state that shows connectedness (e.g. '1') and stores the node ID of the device A 101 in an area, where the node ID of the register is stored. And it starts a transfer of the synchronous communication data with the device A101.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission apparatus for transmitting video, audio, and computer data in real time.

[0002]

2. Description of the Related Art Devices for real-time transmission of data such as video and audio via digital transmission lines have been developed. In order to transmit a video signal or an audio signal as a digital signal, a transmission path capable of synchronous communication is required to guarantee real-time data.

[0003] At present, IEEE 1394 attracts attention as a high-speed serial bus interface. IEEE1
At 394, synchronous communication data such as video and audio can be transmitted using synchronous communication packets.

[0004] In IEEE1394, an identifier (node ID) for identifying each device is allocated. A maximum of 63 devices can be connected to one bus, and each device is assigned a node ID from 0 to 62 in order.
The addition of the node ID is automatically performed by the initialization of the bus that occurs when a new node is added to the bus or when the node is disconnected. When the bus is initialized, the devices connected to the bus transmit packets (self-ID packets) indicating the connection status of the devices to the bus in a predetermined order. The node ID is determined by the order of transmission of the self ID packet. The self ID packet includes the node ID determined at the time of transmission and information indicating whether or not another node is connected to each device. . The devices on the bus can know the tree structure of the bus by receiving and analyzing all the self ID packets sent from each device.

[0005] IEEE 1394 has a capacity of 125 μsec.
It operates based on each cycle (cycle), and can perform two types of transfer, synchronous transfer performed in the first half of each cycle and asynchronous transfer performed in the remaining time after performing the synchronous transfer. . Transfer of data that requires real-time properties such as video data and audio data is transferred using this synchronous transfer, while control information that does not require real-time properties is transferred using asynchronous transfer. Up to 64 synchronous communication packets can be transmitted in one cycle. For identification of the synchronous communication packet, a channel number from 0 to 63 is added to each synchronous communication packet. Also, in order to perform synchronous communication on a plurality of channels, one of the devices connected to the bus manages synchronous communication. Devices that perform this synchronous communication management
Called the bus manager. The bus manager manages the channel numbers used for the synchronous communication and the remaining bands available for the synchronous communication. In order to perform synchronous communication, a channel number and a band to be used must be secured from the bus manager.

[0006]

SUMMARY OF THE INVENTION The above-mentioned IEEE
When performing communication using 1394, it is convenient if each device can easily manage which device is performing synchronous communication.

[0007]

In order to solve the above problems, a data transmission apparatus according to the present invention is a data transmission apparatus in which a plurality of devices are connected and connected to a bus for transmitting synchronous communication data of a plurality of channels. A flag indicating whether or not synchronous communication data is being input / output, and a node ID of a device for which synchronous communication data is to be input / output.
And a channel number of the synchronous communication data to be input / output, and an information management unit that holds at least a band used by the synchronous communication data to be input / output.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings.

First, a first embodiment will be described. FIG.
Are devices A101, B102, C103, and D10 which are data transmission devices via the serial bus 105.
FIG. 4 is a schematic diagram when 4 is connected. Here, it is assumed that the device D is a bus manager that performs synchronous communication management.

First, a case where data transfer is performed between the device A and the device B via the serial bus 105 will be considered. At this time, it is assumed that the device A issues a request for transfer of synchronous communication data such as reading and writing to the device B. FIG. 12 shows the configuration of the devices A and B. FIG. 12 shows a digital interface 1201, a register group 201, and a signal processor 120.
4 is a block diagram of a data transmission device including a recording medium 1203, which is connected to the serial bus 105. The data transmission device 1201 reads out the data recorded on the recording medium 1203, processes the data with the signal processor 1204, and sends out the data to the serial bus 105 via the digital interface 1202. Conversely, after data received from the serial bus 105 via the digital interface 1202 is subjected to signal processing by the signal processor 1204, the data is recorded on the recording medium 1203.
Is performed.

The data transmission device 1201 (device B)
Has a register group 201 which is information management means for managing data transfer with another device. This register group 20
1 will be described below. The structure of this register is shown in FIG.
Shown in As shown in FIG. 3, one register includes a flag unit 301 and an area 302 for storing a node ID. At the time of initialization, the flag portions 301 of all registers are in a state indicating that they are not connected (for example, “0”).

Here, the case where the device A requests the device B to transfer the synchronous communication data will be described. Upon receiving the synchronous communication data transfer request from the device A, the device B first obtains the channel and band of the synchronous communication from the device D which is a bus manager.

Thereafter, the flag unit 301 searches for a register indicating an unconnected state. In the initial state, the flag sections 301 of all the registers indicate an unconnected state. For example, it is assumed that the register 202 is selected as an empty register. Then, the flag unit 301 of the register 202 is changed from a state indicating non-connection to a state indicating connection (for example, “1”), and the area 30 storing the node ID of the register 202 is changed.
2 stores the node ID of the device A. Then, transfer of synchronous communication data with the device A is started.

Next, a case where the device C requests the device B to transfer synchronous communication data during the transfer of the synchronous communication data between the devices A and B will be described. Upon receiving the synchronous communication data transfer request from the device C, the device B acquires a new synchronous communication channel and band from the device D which is a bus manager. Then, the register group 201 is inspected to find a register in which the flag unit 301 indicates an unconnected state. Now, since the flag portion of the register 202 is in the connected state, the register 203 is set as an empty register.
I will use. Then, the flag unit 301 of the register 203 is changed to the connection state, and the node ID of the device C is stored in the area 302 of the register 203 where the node ID is stored. Then, the transfer of the synchronous communication data with the device C is started.

Next, a case where the synchronous communication data between the devices A and B is terminated will be described. In this case, first, device B
Returns the used channel number and band to the device D. Then, the device B finds a register that manages synchronous communication data with the device A by searching for a node ID stored in each register. Register 20
Since the node ID stored in 2 is the node ID of the device A, it can be understood that the register managing the connection with the device A is the register 202. Then, the flag unit 301 of the register 202 is changed from the connected state to the unconnected state. As a result, the register 202 becomes an empty register.

Next, a second embodiment will be described. The second embodiment differs from the first embodiment in that the register group 20
1 is that the configuration of each register is similar to the configuration of the register 401 in FIG. That is, the flag unit 301 is eliminated and only the area for storing the node ID is provided.

At the time of initialization, a value "63" is set as a node ID in each register 401 of the register group 201. Since only a value from 0 to 62 is used as the value of the node ID, the value “63” indicates that the register is unused.

A case where the device A requests the device B to transfer synchronous communication data will be described. Device B is device A
When a request for transferring synchronous communication data is received from the CPU, a search is made for a register in which the register is not connected, that is, a register having a value of "63". In the initial state, all the registers are in the unconnected state. For example, assume that the register 202 is selected as an empty register. Then, the node ID of the device A is stored in the register 202. Then, transfer of synchronous communication data with the device A is started.

Next, a case where the synchronous communication data between the devices A and B is terminated will be described. In this case, the device B can find the register managing the synchronous communication data with the device A by searching the node ID stored in each register. Since the node ID stored in the register 202 is the node ID of the device A,
The register managing the connection with the device A is the register 20
It turns out that it is 2. Then, the value of the register 202 is changed to “63”. As a result, the register 202 becomes an empty register.

As described above, by using the embodiments of the first and second embodiments of the data transmission apparatus of the present invention, it is possible to easily determine which one apparatus is transmitting synchronous communication data with another apparatus. Can be managed. Also, by reading the register that manages the synchronous communication data from a device other than the device that is performing the synchronous communication, it is possible to determine with which device the device having the register is transmitting the synchronous communication data. You can easily find out.

Next, a third embodiment will be described with reference to FIG. 1, FIG. 2, FIG. 5, and FIG. As in the first embodiment,
It is assumed that data is transferred between the device A and the device B via the serial bus 105. The device B has a configuration like the data transmission device 1201 of FIG. 12, and has a register group 201 for managing data transfer with another device. FIG. 2 shows the configuration of this register. As shown in FIG. 5, one register has a flag section 501, an area 502 for storing a node ID, and an area 50 for storing a channel number.
3 At the time of initialization, the flag portions 501 of all the registers are in a state (for example, “0”) indicating no connection.

Here, the case where the device A requests the device B to transfer the synchronous communication data will be described. Upon receiving the synchronous communication data transfer request from the device A, the device B acquires a channel and a band of the synchronous communication from the device D which is a bus manager. Then, the device B searches for a register in which the flag unit 501 indicates an unconnected state. In the initial state, the flag sections 501 of all the registers indicate an unconnected state. For example, it is assumed that the register 202 is selected as an empty register.

The flag section 501 of the register 202 is changed from a state indicating non-connection to a state indicating connection (for example, "1").
And the node ID of the device A is stored in the area 502 of the register 202 where the node ID is stored. In addition, the channel number acquired from the device D is stored in the channel number storage area 503 of the register 202. Then, transfer of synchronous communication data with the device A is started.

Next, when the device C requests the device B to transfer the synchronous communication data during the transfer of the synchronous communication data between the device A and the device B, the device B becomes the empty register 203.
To perform the same operation as the above operation.

Next, a case where the synchronous communication data between the device A and the device B ends will be described. The device B returns to the device D the channel and band used for transferring the synchronous communication data with the device A. Then, the device B finds a register that manages synchronous communication data with the device A by searching for a node ID stored in each register. Since the node ID stored in the register 202 is the node ID of the device A, it is understood that the register managing the connection with the device A is the register 202. Then, the flag unit 501 of the register 202 is changed from the connected state to the unconnected state. This allows register 20
2 is an empty register.

As described above, by using the form of the third embodiment of the data transmission apparatus of the present invention, it is possible to determine which one apparatus is transmitting synchronous communication data with another apparatus, and It is possible to easily manage which channel is used for transmission. Also, from a device different from the device performing the synchronous communication, by reading the register that manages the synchronous communication data, to which device the device having the register is transmitting the synchronous communication data, And you can easily know which channel you are using.

Next, a fourth embodiment will be described with reference to FIG. 1, FIG. 2, FIG. 6, and FIG. As in the first embodiment,
It is assumed that data is transferred between the device A and the device B via the serial bus 105. The device B has a configuration like the data transmission device 1201 of FIG. 12, and has a register group 201 for managing data transfer with another device. FIG. 2 shows the configuration of this register. Register group 20
One of the registers is a flag unit 6 as shown in FIG.
01, an area 602 for storing the node ID, and an area 603 for storing the used bandwidth. At initialization,
The flag sections 601 of all the registers are in a state indicating that they are not connected (for example, “0”).

Here, the case where the device A requests the device B to transfer the synchronous communication data will be described. Upon receiving the synchronous communication data transfer request from the device A, the device B acquires a channel and a band of the synchronous communication from the device D which is a bus manager. Then, the device B searches for a register in which the flag unit 601 indicates an unconnected state. Now, assume that the register 202 is selected as an empty register. Then, the flag unit 601 of the register 202 is changed from a state indicating non-connection to a state indicating connection (for example, “1”), and
The node ID of the device A is stored in the area 602 for storing the node ID of the second device.

The band obtained from the device D is stored in the area 603 of the register 202 for storing the used band.
Then, transfer of synchronous communication data with the device A is started.

Next, when the device C requests the device B to transfer the synchronous communication data during the transfer of the synchronous communication data between the device A and the device B, the device B becomes the empty register 203.
To perform the same operation as the above operation.

Next, a case where the synchronous communication data between the devices A and B is ended will be described. The device B returns to the device D the channel and band used for transferring the synchronous communication data with the device A. Then, the device B finds a register that manages synchronous communication data with the device A by searching for a node ID stored in each register. Since the node ID stored in the register 202 is the node ID of the device A, it is understood that the register managing the connection with the device A is the register 202. Then, the flag unit 601 of the register 202 is changed from the connected state to the unconnected state. This allows register 20
2 is an empty register.

As described above, by using the data transmission apparatus according to the fourth embodiment of the present invention, it is possible to determine which one device is transmitting synchronous communication data with another device, The bandwidth used for transmission of data can be easily managed. Also, from a device different from the device performing the synchronous communication, by reading the register that manages the synchronous communication data, to which device the device having the register is transmitting the synchronous communication data, And you can easily know the band used.

Next, a fifth embodiment will be described with reference to FIGS. 1, 2, 7, and 12. FIG. As in the first embodiment,
It is assumed that data is transferred between the device A and the device B via the serial bus 105. The device B has a configuration like the data transmission device 1201 of FIG. 12, and has a register group 201 for managing data transfer with another device. FIG. 2 shows the configuration of this register. Register group 20
One of the registers is a flag unit 7 as shown in FIG.
01, an area 702 for storing a node ID, an area 703 for storing a channel number, and an area 704 for storing a used band. At the time of initialization, the flag portions 701 of all the registers are in a state indicating no connection (for example, “0”).
It has become.

Here, the case where the device A requests the device B to transfer the synchronous communication data will be described. Upon receiving the synchronous communication data transfer request from the device A, the device B acquires a channel and a band of the synchronous communication from the device D which is a bus manager. Then, the device B searches for a register in which the flag unit 701 indicates an unconnected state. Now, assume that the register 202 is selected as an empty register.

Then, the flag unit 701 of the register 202 is changed from a state indicating non-connection to a state indicating connection (for example, "1").
And the node ID of the device A is stored in the area 702 of the register 202 where the node ID is stored. Also, device D
The channel number of the synchronous communication obtained from
The bandwidth acquired from the device D is stored in the area 704 storing the used bandwidth in the area 703 storing the channel number 2. Then, transfer of synchronous communication data with the device A is started.

Next, when the device C requests the device B to transfer the synchronous communication data during the transfer of the synchronous communication data between the device A and the device B, the device B becomes the empty register 203.
To perform the same operation as the above operation.

Next, a case where the synchronous communication data between the devices A and B is ended will be described. The device B returns to the device D the channel and band used for transferring the synchronous communication data with the device A. Then, the device B finds a register that manages synchronous communication data with the device A by searching for a node ID stored in each register. Since the node ID stored in the register 202 is the node ID of the device A, it is understood that the register managing the connection with the device A is the register 202. Then, the flag unit 701 of the register 202 is changed from the connected state to the unconnected state. This allows register 20
2 is an empty register.

As described above, by using the fifth embodiment of the data transmission apparatus of the present invention, it is possible to determine which one device transmits synchronous communication data with another device, Channels and bands used for transmission of data can be easily managed. Also, by reading the register that manages the synchronous communication data from a device other than the device performing the synchronous communication,
It is possible to easily know with which device the device having the register is transmitting synchronous communication data, and the channel and band used.

In this embodiment, the node ID has been described as a 6-bit value indicating a value from 0 to 62.
This is a 10-bit bus ID in IEEE1394
16-bit value may be added. For example,
When a 16-bit ID is stored in the register configuration of FIG. 3, the configuration becomes as shown in FIG. Further, in this case, the empty register in the second embodiment stores the value of the lower 6 bits of the 16-bit ID as “11111” in binary notation.
1 "or the like.

In this embodiment, for example, when the device A requests the device B to start synchronous communication data, the case where the device B acquires a channel and a band for transmitting the synchronous communication data from the bus manager will be described. However, this may be performed by the device A before requesting the start of synchronous communication data.

In this embodiment, an apparatus for recording and reproducing data from the recording medium 1203 as shown in FIG. 12 has been described as a data transmission apparatus. However, this may be a data transmission apparatus having another configuration. For example, data received from a broadcast system is transmitted to the digital interface 12.
A data transmission device that outputs the data to the serial bus 105 via the communication bus 02 may be used.

In the third, fourth, and fifth embodiments, the case where the register has the flag portion and the area for storing the node ID has been described. However, this is the same as in the second embodiment. Alternatively, a register configuration without a flag section may be adopted. In this case, the register configurations in FIGS. 5, 6, and 7 are as shown in FIGS. 9, 10, and 11, respectively. In this case, as in the method described in the second embodiment, the value of the area storing the node ID is set to “6” in the empty register.
3 ". When storing a 16-bit ID, a method of setting the lower 6 bits to “111111 (binary representation)” or the like is used.

Further, for example, the positional relationship between the flag 301 and the node ID 302 in FIG. 3 is not limited to this, and the flag 301 may be provided after the node ID 302. In addition, regarding these positional relationships, FIGS.
The same applies to FIG.

[0044]

As described above, the data transmission apparatus of the present invention has a register for managing the transmission of synchronous communication data. When transmitting synchronous communication data, the node ID of the transmitting device, the band used for transmission, and the channel are stored in the management register.

As a result, it is possible to easily manage which device is transmitting synchronous communication data with which other device, and the channel and band used for transmitting the synchronous communication data.

Also, by reading a register that manages synchronous communication data from a device other than the device performing the synchronous communication, the device having the register transmits the synchronous communication data to any device. You can easily find out which channels and bands you are using.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a device connection state for explaining an embodiment of the present invention.

FIG. 2 is a schematic diagram of a register group for explaining an embodiment of the present invention;

FIG. 3 is a schematic diagram of a register configuration for explaining an embodiment of the present invention.

FIG. 4 is a schematic diagram of a register configuration for explaining an embodiment of the present invention;

FIG. 5 is a schematic diagram of a register configuration for explaining an embodiment of the present invention.

FIG. 6 is a schematic diagram of a register configuration for explaining an embodiment of the present invention.

FIG. 7 is a schematic diagram of a register configuration for explaining an embodiment of the present invention.

FIG. 8 is a schematic diagram of a register configuration for explaining an embodiment of the present invention.

FIG. 9 is a schematic diagram of a register configuration for explaining an embodiment of the present invention.

FIG. 10 is a schematic diagram of a register configuration for explaining an embodiment of the present invention.

FIG. 11 is a schematic diagram of a register configuration for explaining an embodiment of the present invention.

FIG. 12 is a diagram showing the configuration of the device shown in FIG.

[Explanation of symbols]

 101, 102, 103, 104 Equipment 105 Bus 1201 Data transmission device 1202 Digital interface 1203 Recording medium 1204 Signal processor

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hidetoshi Takeda 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A plurality of devices are connected to a bus for transmitting communication data of a plurality of channels, each of the devices has a node ID which is an identifier determined by a connection mode, and one of the bandwidths of the bus. A data transmission device for acquiring a part prior to the transmission of the communication data, wherein a flag indicating whether or not the communication data is being input / output, and a target for the communication data input / output. A data transmission device comprising: an information management unit that holds at least the node ID of a device. 2. A plurality of devices are connected to a bus for transmitting communication data of a plurality of channels, each of the devices individually has a node ID which is an identifier determined by a connection mode, and one of the bandwidths of the bus. A data transmission device for acquiring a part before transmitting said communication data, wherein a flag indicating whether or not synchronous communication data is being input / output, and a target for synchronous communication data input / output. A data transmission device comprising: information management means for holding at least a node ID of a device and a channel number of synchronous communication data to be input / output. 3. A plurality of devices are connected to a bus for transmitting communication data of a plurality of channels, each of the devices individually has a node ID which is an identifier determined by a connection mode, and one of the bandwidths of the bus. A data transmission device for acquiring a part before transmitting said communication data, wherein a flag indicating whether or not synchronous communication data is being input / output, and a target for synchronous communication data input / output. A data transmission device comprising: an information management unit that holds at least a node ID of a device and band information used by input / output synchronous communication data. 4. A plurality of devices are connected to a bus for transmitting communication data of a plurality of channels, each of the devices has a node ID which is an identifier determined by a connection mode, and one of the bandwidths of the bus. A data transmission device for acquiring a part before transmitting said communication data, wherein a flag indicating whether or not synchronous communication data is being input / output, and a target for synchronous communication data input / output. A data transmission device comprising: an information management unit that holds at least a node ID of a device, a channel number of synchronous communication data to be input / output, and a band used by the synchronous communication data to be input / output.