JPH11317755A - Data communication system, its method, its equipment and digital interface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain technique capable of consecutively and surely transferring object data unnecessitating real time property by differentiating a memory space housing information data on a data communication system communicating through the use of a logical connection relation by each logical connecting relation. SOLUTION: A first memory space 310 and an n-th memory space 314 are inside of a destination node 304 and designated by a prescribed destination offset. In this case, at least one connection can be set between a source node 302 and at least one destination node 304. In a case when the transferring request of some object data exists, one or plural controllers 200 set these connections based on a communication protocol. In addition, one or plural usable destination offsets can be set in one connection.

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, a data communication method, a data communication device, and a digital interface, and more particularly, to a network for performing high-speed communication by mixing information data (including image data) and command data. It relates to a communication protocol applicable to the network.

[0002]

2. Description of the Related Art Conventionally, personal computers (hereinafter, referred to as personal computers).
Among the peripheral devices of the personal computer (PC), hard disk drives and printers were the most frequently used. These peripheral devices are provided with a dedicated input / output interface or SCSI (smaller
l Computer system interface) It was connected to a PC by a versatile digital interface such as an interface.

On the other hand, in recent years, AV (Audio / Visual) devices such as digital cameras and digital video cameras have attracted attention as one of the peripheral devices of PCs. These AVs (Au
dio / Visual) devices were also connected to a PC via a dedicated interface.

FIG. 15 is a diagram showing a conventional communication system composed of a PC and AV equipment. In FIG. 15, 101 is an AV device (digital camera), and 102 is a P
C and 103 are printers.

In the digital camera 101, reference numeral 104 denotes a memory for compressing and recording a captured image, and 105 denotes a memory 1
A decoding unit for expanding and decoding the compressed image data recorded in 04, an image processing unit 106, a D / A converter 107, a display unit 108 including an EVF, and a digital camera 109 for connecting the camera 101 and the PC 102 It is a dedicated digital I / O unit.

In the PC 102, 110 is the PC 102
Dedicated digital I that connects the camera to the digital camera 101
/ O unit, 111 is an operation unit including a keyboard and a mouse, 112 is a decoding unit for expanding and decoding compressed image data, 113 is a display, 114 is a hard disk,
115 is a memory such as a RAM, 116 is an MPU, 117 is a PCI bus, and 118 is a SCSI interface connecting the PC 102 and the printer 103.

In the printer 103, 119 is a SCSI interface for connecting the printer 103 and the PC 102, 120 is a memory, 121 is a printer head, 12
Reference numeral 2 denotes a printer controller for controlling the operation of the printer 103, and reference numeral 123 denotes a driver.

In a conventional communication system, the digital interface (digital I / O unit 109) of the digital camera 101 and the digital interface (SCSI interface 110) of the printer 103 are not compatible, and it is not possible to connect them directly. could not. Therefore, the digital camera 101
In addition, for example, when a still image is to be communicated, the communication must be performed via a PC.

In addition, conventional dedicated interfaces and SCSI
The interface has a low data transfer rate, a thick communication cable for parallel communication, and a small number and types of peripheral devices that can be connected, particularly when handling large-capacity data such as still images and moving images of AV devices. There are many problems, such as limitations on connection methods and the inability to perform real-time data transfer.

As one of the next-generation high-speed, high-performance digital interfaces that solves these problems, the IE
EE (The Institute of Electrical and Electronics
Engineers, Inc.) 1394-1995 standard is known.

A digital interface (hereinafter, 1394 interface) conforming to the IEEE 1394-1995 standard has the following features. (1) The data transfer speed is high. (2) Real-time data transfer method (that is, Isochron
ous transfer method) and Asynchronous transfer method. (3) A highly flexible connection configuration (topology) can be constructed. (4) Supports plug-and-play function and hot-swap function.

[0012]

SUMMARY OF THE INVENTION However, the IEEE
The E1394-1995 standard defines the physical and electrical configuration of the connector, the two most basic data transfer methods, and the like. However, what kind of data is used in what data format, The communication protocol based on which transmission / reception is not defined.

[0013] Also, according to the IEEE 1394-1995 standard,
In the sochronous transfer method, since a response to an outgoing packet is not specified, each isochronous transfer method
There is no guarantee that the ous packet has been received reliably.
Therefore, when it is desired to reliably transfer a plurality of continuous data, or when it is desired to divide one file data into a plurality of data and transfer them reliably, Isochronous is used.
The transfer method could not be used.

Further, according to the IEEE 1394-1995 standard,
In the sochronous transfer method, the total number of communications is limited to 64 even if there is a vacancy in the transfer band. For this reason, if you want to perform many communications with a small transfer band,
The Isochronous transfer method could not be used.

According to the IEEE 1394-1995 standard, when a bus reset occurs in response to ON / OFF of a power supply of a node, connection / disconnection of a node, or the like, data transfer must be interrupted. However, IEEE13
In the 94-1995 standard, when data transfer was interrupted due to a bus reset or transmission error, it was not possible to know what kind of data was lost. Further, in order to recover the transfer once interrupted, it was necessary to take a very complicated communication procedure.

Here, the bus reset is a function for automatically recognizing a new topology and setting an address (node ID) assigned to each node. With this function, the IEEE1394-1995 standard uses plugs
An AND play function and a hot-swap function can be provided.

In a communication system conforming to the IEEE 1394-1995 standard, real-time properties are not required, but object data (for example, still image data, graphics data, text data, etc.) that requires a relatively large amount of data that requires reliability. A communication protocol for dividing data, file data, program data, and the like into one or more segment data and continuously transferring the data has not been specifically proposed.

In a communication system conforming to the IEEE 1394-1995 standard, a communication protocol for realizing data communication between a plurality of devices using a communication system for asynchronously broadcasting data has not been proposed. .

The present invention has been made in view of the above problems, and has been made in view of the above circumstances. A technique capable of continuously and reliably transferring object data that does not require real-time processing in a data communication system, a data communication method, a data communication device, and a digital interface. The purpose is to provide. Another object of the present invention is to provide a data communication system, a data communication method, a data communication device, and a digital interface, wherein a logical connection relationship between a source node and one or more destination nodes, It is an object of the present invention to provide a technology capable of associating a memory space of a destination node with an offset address commonly designating the offset address, simplifying the offset address, and simplifying the determination of the connection ID of the received data. Another object of the present invention is to provide a data communication system, a data communication method, a data communication device, and a digital interface, wherein a delay time that occurs until data communication between a source node and a plurality of destination nodes is started. It is an object of the present invention to provide a technique capable of suppressing an increase in the number of images.
Another object of the present invention is to solve the inconvenience of the conventional communication system, to transfer data at high speed and easily, and to ensure that data can be transferred. . Another object of the present invention is to enable a large number of communications to be performed simultaneously when a communication band is not used much. Another object of the present invention is to make it possible to easily detect data lost due to interruption of data transfer and to reliably and easily recover from the interruption of data transfer. The purpose is to:

[0020]

A data communication system according to the present invention uses a logical connection established between a transmitting device for transmitting information data and a receiving device for receiving the information data. A data communication system that performs
A memory space for storing the information data is different for each logical connection relationship. Another feature of the data communication system of the present invention is a data communication system including a plurality of devices, wherein communication between a plurality of different devices is determined by a plurality of different ID information, and the communication is performed. Is stored in a plurality of different memory spaces corresponding to the ID information. Another feature of the data communication system of the present invention is that a data communication device includes a transmitting device that transmits information data, a receiving device that receives the information data, and a management device that manages communication of the information data. In the communication system, after the transmission device, the reception device, and the management device set a logical connection relationship between the transmission device and the reception device, the transmission device sets the logical connection relationship. The information data is transmitted to a corresponding memory space. Another feature of the data communication system of the present invention is that a source node that transfers data including at least one segment using at least one asynchronous communication, and that the data transferred from the source node is transmitted. One or more destination nodes for receiving, and a controller for setting a logical connection relationship between the source node and the one or more destination nodes; and at least one of the source node and the controller. One is characterized in that the timing for performing the asynchronous communication is controlled. Another feature of the data communication system of the present invention is that a source node transfers data including one or more segments using at least one broadcast, and receives the data transferred from the source node. And one or more destination nodes, wherein the source node and the one or more destination nodes are:
The transfer of the data is managed based on a logical connection relationship set between the source node and the destination node.

A data communication device according to the present invention is a data communication device connectable to a communication system constituted by a plurality of devices, and includes a transmitting device for transmitting information data and a receiving device for receiving the information data. Communication means for performing communication using a logical connection relationship set therebetween, and storage means for storing a memory space for storing the information data in association with the logical connection relationship. .

A data communication method according to the present invention is a data communication method for performing communication using a logical connection established between a transmitting device for transmitting information data and a receiving device for receiving the information data. The information data is stored in different memory spaces depending on each logical connection relationship. Another feature of the data communication method of the present invention is a data communication method using a communication method of continuously and asynchronously transmitting a plurality of communication packets, wherein a memory space of the plurality of devices is used. The information transmitted by the communication method is stored in the same area. Another feature of the data communication method of the present invention is a data communication method applicable to a data communication system including a plurality of devices, wherein communication between a plurality of different devices is performed using a plurality of different IDs. It is characterized by discriminating based on information and storing information transmitted by the communication in a plurality of different memory spaces corresponding to the ID information. Another feature of the data communication method of the present invention is that the data communication method includes a transmitting device that transmits information data, a receiving device that receives the information data, and a management device that manages communication of the information data. A data communication method applicable to a communication system, wherein after setting the logical connection relationship between the transmitting device and the receiving device, controlling the transmitting device, the receiving device, and the management device. The transmitting device is controlled to transmit the information data to a memory space corresponding to the logical connection relationship. Another feature of the data communication method of the present invention is that a logical connection relationship is established between a source node and one or more destination nodes, and the data communication method comprises one or more segments. Transferring to the one or more destination nodes using at least one asynchronous communication, and receiving the data transferred using the asynchronous communication using the logical connection relationship. It is characterized by: Another feature of the data communication method of the present invention is that the source node and the
Establishing a logical connection relationship with one or more destination nodes; and transferring data comprising one or more segments to the one or more destination nodes using at least one asynchronous communication. And performing a step of receiving data transferred using the broadcast communication based on the logical connection relationship.

[0023] The digital interface of the present invention establishes a logical connection relationship between means for packetizing data comprising one or more segments into at least one communication packet and one or more destination nodes. Means for asynchronously transferring the communication packet by using the digital interface.
Further, another feature of the digital interface of the present invention is that a means for receiving at least one communication packet asynchronously transferred using a logical connection relationship set with a source node, Means for writing data contained in the packet into a common memory space with other devices. According to another feature of the digital interface of the present invention, a means for setting a logical connection between a source node and one or more destination nodes is provided, and the logical connection is identified. Means for notifying the connection ID to the source node and the one or more destination nodes.

[0024]

Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram illustrating an example of a configuration of a data communication system according to the present embodiment. As shown in FIG. 1, the data communication system according to the present embodiment includes a computer 10, a digital video recorder 28 integrated with a camera, and a printer 60.

First, the configuration of the computer 10 will be described. An arithmetic processing unit (MPU) 12 controls the operation of the computer 10. 14 is IEEE1394-
This is a 1394 interface having a function based on the 1995 standard and a function related to a communication protocol defined in the present embodiment.

An operation unit 16 includes a keyboard, a mouse, and the like. A decoder 18 decodes compression-coded digital data (moving image data, still image data, audio data, and the like). Reference numeral 20 denotes a display unit (display) including a display device such as a CRT display or a liquid crystal panel.

Reference numeral 22 denotes a hard disk (HD) for recording various digital data (moving image data, still image data, audio data, graphics data, text data, program data, etc.). 24 is an internal memory. Reference numeral 26 denotes an internal bus, such as a PCI bus, for connecting each processing unit inside the computer 10 to each other.

Next, the configuration of a camera-integrated digital video recorder (hereinafter referred to as DVCR) 28 will be described. An imaging unit (opt) 30 converts an optical image of a subject into an electric signal and converts the electric signal into an electric signal. 32 is an analog-digital (A / D) converter.

Reference numeral 34 denotes an image processing unit for converting a digitized moving image or still image into digital image data of a predetermined format. A compression / decompression processing unit 36 has a function of decoding compression-encoded digital data (moving image data, still image data, audio data, and the like), and performs highly efficient encoding of digital image data (for example,
Like the MPEG system and the DV system, a function of performing orthogonal transformation for a predetermined image unit, quantizing the image, and performing variable-length encoding is provided.

Numeral 38 is a memory for temporarily storing digital image data which has been encoded with high efficiency. Reference numeral 40 denotes a memory for temporarily storing digital image data that has not been encoded with high efficiency. 42 is a data selector. 4
Reference numeral 4 denotes a 1394 interface having a function based on the IEEE 1394-1995 standard and a function related to a communication protocol defined in the present embodiment.

Memory control units 46 and 48 control writing and reading of the memory 38 and the memory 40. 5
Reference numeral 0 denotes a control unit (system controller) that controls the operation of the DVCR 28, and includes a microcomputer.
An operation unit 52 includes a remote control, an operation panel, and the like.
Reference numeral 54 denotes an electronic viewfinder (EVF). 56 is a D / A converter.

Reference numeral 58 denotes a recording / reproducing unit comprising a recording medium such as a magnetic tape, a magnetic disk, and a magneto-optical disk, which records and reproduces various digital data (moving image data, still image data, audio data, etc.).

Next, the configuration of the printer 60 will be described. Reference numeral 62 denotes a 1394 interface having a function based on the IEEE 1394-1995 standard and a function related to a communication protocol defined in the present embodiment. 64
Is a data selector. An operation unit 66 includes operation buttons, a touch panel, and the like.

A printer controller 68 controls the operation of the printer 60. 70 is a decoder. 72
Is an internal memory. An image processing unit 74 processes still image data, text data, graphics data, and the like received via the 1394 interface. 7
6 is a driver. Reference numeral 78 denotes a printer head.

As shown in FIG. 1, a computer 10, D
Each communication device (hereinafter, referred to as a node) of the VCR 28 and the printer 60 includes 1394 interfaces 14, 44,
(Hereinafter, a network configured by a 1394 interface is connected to a 139 interface).
4 serial bus).

Each node transmits and receives various types of object data (for example, moving image data, still image data, audio data, graphics data, text data, program data, etc.) and defines commands by defining a predetermined communication protocol. Remote operation by data becomes possible. In the present embodiment, a communication protocol using the Asynchronous transfer method is defined.

Next, the operation of each node constituting the communication system of this embodiment will be described with reference to FIG. First,
The function and operation of each processing unit included in the computer 10 will be described. In this embodiment, the computer 10
For example, a controller that controls transmission and reception of image data between the DVCR 28 and the printer 60, or a DV
It operates as a controller for remotely controlling the CR 28 and the printer 60.

The MPU 12 executes software recorded on the hard disk 22 and moves various data to the internal memory 24. Also, MPU12
Performs the arbitration operation of each processing unit connected by the internal bus 26, and the like.

The 1394 interface 14 is a 1394 interface.
While receiving the image data transferred on the serial bus, the image data recorded on the hard disk 22 or the internal memory 24 can be transmitted on the 1394 serial bus. Also, the 1394 interface 14
It is also possible to transmit command data for remotely controlling another node on the 394 serial bus. Furthermore,
The 1394 interface 14 also has a function of transferring a signal transferred via the 1394 serial bus to another node.

The user selects desired software via the operation unit 16 and causes the MPU 12 to execute the software recorded on the hard disk 22. Here, information on the software is presented to the user by the display unit 20. The decoder 18 decodes the image data received from the 1394 serial bus based on the software. The decoded image data is
The information is presented to the user by the display unit 20.

Next, the function and operation of each processing unit constituting the DVCR 28 will be described. In this embodiment, DVC
The R28 operates as an image transmission device (source node) for asynchronously transferring image data based on the communication protocol of the present embodiment, for example. Imaging unit 3
0 converts the optical image of the subject into an electric signal composed of a luminance signal (Y) and a color difference signal (C), and converts the electric signal to A
/ D converter 60. A / D converter 32 digitizes the electric signal.

The image processing section 34 performs predetermined image processing on the digitized luminance signal and color difference signal, and multiplexes them. The compression / expansion processing unit 36 compresses the data amount of the digitized luminance signal and color difference signal. Here, the compression / expansion processing unit 36 may process the luminance signal and the color difference signal in parallel using independent compression processing circuits. Alternatively, they may be processed in a time sharing manner using a common compression processing circuit.

The compression / decompression processing section 36 performs shuffling processing on the compressed image data in order to make the transmission image error-resistant. This makes it possible to convert a continuous code error (ie, a burst error) into a discrete error (ie, a random error) that can be easily corrected or interpolated. Here, when it is desired to equalize the deviation of the information amount due to the density of the image within the screen, if this processing step is brought before the compression processing, it is convenient to use variable length coding such as run length. .

The compression / expansion processing section 36 adds data identification information (ID) for restoring shuffling to the compressed image data. The compression / expansion processing unit 36 adds an error correction code (ECC) to the compressed image data in order to reduce errors during recording and reproduction.

The image data compressed by the compression / expansion processing unit 36 is supplied to the memory 38 and the recording / reproducing unit 58. The recording / reproducing unit 58 records the compressed image data to which the ID and the ECC are added on a recording medium such as a magnetic tape. Here, the compressed image data is recorded in an independent recording area different from the audio data.

On the other hand, the D / A converter 56
The image data supplied to is subjected to D / A conversion. EVF
54 displays the analog image signal supplied from the D / A converter 56. The image data processed by the image processing unit 34 is also supplied to the memory 40. Here, the memory 40 stores uncompressed image data.

The data selector 42 selects the memory 38 or the memory 40 based on a user's instruction, and supplies compressed image data or uncompressed image data to the 1394 interface 44. Also, the data selector 42
4 supplies the image data supplied from the interface 44 to the memory 38 or the memory 40.

The 1394 interface 44 transfers compressed image data or uncompressed image data asynchronously based on a communication protocol of the present embodiment described later. Also, the 1394 interface 44 is
A control command for controlling the DVCR 28 is received via the serial bus. The received control command is
The data is supplied to the control unit 50 via the data selector 42. The 1394 interface 44 returns a response to the control command.

Next, the function and operation of each processing section constituting the printer 60 will be described. In the present embodiment, the printer 60 is, for example, an image receiving apparatus (destination / image receiving apparatus) that receives and prints image data transferred asynchronously based on the communication protocol of the present embodiment.
Node).

The 1394 interface 62 is
Asynchronously transferred image data and control commands are received via a serial bus. 139
The four interface 62 transmits a response to the control command.

The received image data is supplied to the decoder 70 via the data selector 64. Decoder 7
0 decodes the image data and outputs the result to the image processing unit 74. The image processing unit 74 temporarily stores the decoded image data in the memory 72.

The image processing section 74 converts the image data temporarily stored in the memory 72 into print data.
It is supplied to the printer head 78. The printer head 78 executes printing based on the control of the printer controller 68.

On the other hand, the received control command is input to the printer controller 68 via the data selector 64. The printer controller 68 performs various controls related to printing based on the control data. For example,
The paper feed by the driver 76, the position of the printer head 78, and the like are controlled.

Next, the configuration of the 1394 interfaces 14, 44 and 62 of this embodiment will be described in detail with reference to FIG. The 1394 interface is functionally composed of a plurality of layers (layers).

In FIG. 8, the 1394 interface is connected to a 1394 interface of another node via a communication cable 801 conforming to the IEEE 1394-1995 standard. The 1394 interface is 1
One or more communication ports 802, each communication port 802
Is the physical layer 803 included in the hardware unit
Connected to

Referring to FIG. 8, the hardware section includes a physical layer 803 and a link layer 804. The physical layer 803 includes a physical / electrical interface with other nodes, detection of bus reset and associated processing, encoding / decoding of input / output signals,
Arbitrates the right to use the bus. Also, link layer 804
Performs generation of communication packets, transmission and reception of various communication packets, control of a cycle timer, and the like. In addition, the link layer 804 includes an asynchronous broadcast packet described later.
It provides functions for generating, transmitting and receiving.

In FIG. 8, the firmware section
It includes a transaction layer 805 and a serial bus management 806. The transaction layer 805 manages the asynchronous transfer method and provides various transactions (read, write, lock).

The transaction layer 805 includes:
Provides the Asynchronous broadcast transaction function described later. The serial bus management 806 controls the own node, manages the connection state of the own node, and manages the ID of the own node based on the IEEE1212 CSR standard described later.
Provides functions for information management and serial bus network resource management.

The hardware section and the firmware section shown in FIG. 8 substantially constitute a 1394 interface, and the basic configuration thereof is based on IEEE1394-1.
995 standard.

The application layer 807 included in the software unit differs depending on the application software used, and controls what kind of object data is transferred and how.

The communication protocol of this embodiment described later is 1
The extension of the functions of the hardware section and the firmware section constituting the 394 interface provides a new transfer procedure to the software section.

(First Embodiment) Next, a basic configuration of a communication protocol defined in this embodiment will be described with reference to FIG. In FIG. 2, 300 is a controller,
302 is a source node, 304 is n (n ≧ 1) destination nodes, 306 is a subunit (subunit) of the source node, 308 is still image data, graphics data, text data,
Object data such as file data and program data.

310 is the destination node 30
4 is a first memory space inside a predetermined destination offset (destination # o).
ffset # 0). 312 is the source
This is a first connection indicating a logical connection relationship (ie, connection) between the node 302 and the destination node 304. Here, the destination offset is an address that commonly specifies the memory space of the n destination nodes 304.

314 is the destination node 30
4 is an n-th memory space inside a predetermined destination offset (destination # o).
ffset # n). 316 is the source
This is an n-th connection indicating a logical connection relationship (that is, connection) between the node 302 and the destination node 304.

In this embodiment, each node stores the first memory space 310 to the n-th memory space 314 in the IEEE.
1212 CSR (Control Status)
It is managed in a 64-bit address space that conforms to the Register Architecture (Register Architecture) standard (or ISO / IEC 13213: 1994 standard).
The IEEE 1212 CSR standard is a standard that specifies control, management, and address allocation for a serial bus.

FIG. 6 is a diagram for explaining the address space of each node. FIG. 6A shows a logical memory space represented by a 64-bit address.
Also, FIG. 6 (b), a part of the memory space shown in FIG. 6 (a), for example, an address space the upper 16 bits are FFFF _16. First memory space 310 shown in FIG.
The nth memory space 314 uses a part of the memory space shown in FIG. Each memory space 310-314
Is specified by a destination offset indicating the lower 48 bits of the address.

In FIG. 6B, for example, 00000
00000000 _{16 to} 000000003 FF ₁₆ are reserved areas, and the area where the object data 308 is actually written has the lower 48 bits of the address as FF.
FFF0000400 ₁₆ or later to become the region.

In FIG. 2, a source node 302 is a node having a function of transferring object data 308 in accordance with a communication protocol described later, and a destination node 304 is a source node 302.
Is a node having a function of receiving the object data 308 transferred from. The controller 300 is
Source node 302 according to the communication protocol described below.
A node having a function of setting a logical connection relationship (that is, a connection) between and one or more destination nodes 304 and managing the logical connection relationship.

Here, the controller 300, the source node 302, and the destination node 304 may function as independent and separate nodes. or,
Controller 300 and source node 302 may function in one and the same node. Also, the controller 300 and the destination node 304
It may work in two same nodes. In this case, a transaction between the controller 300 and the source node 302 or the destination node 304 becomes unnecessary, and the communication procedure is simplified.

In this embodiment, the controller 300, the source node 302, and the destination node 304
Will function in independent and separate nodes. For example, 1394 interface 1
4 having a controller 300
Function as The DVCR 28 having the 1394 interface 44 is connected to the source nodes 302 and 1394.
The printer 60 including the interface 62 functions as the destination node 304.

In this embodiment, as shown in FIG. 2, one or more connections can be set between the source node 302 and one or more destination nodes 304. These connections are set by one or more controllers 300 based on a communication protocol to be described later, when there is a transfer request for certain object data.

In this embodiment, one or more destination offsets that can be used in one connection can be set. The value of the destination offset may be a preset value or a value variably set by the controller 300 or the source node 302. Note that the relationship between the connection and the destination offset is set based on a communication protocol described later.

When a plurality of destination offsets are set in one connection, a plurality of forms of data communication can be simultaneously realized by one connection. For example, by assigning different destination offsets for each form of data communication,
One-to-one, one-to-one, and N-to-N data communications can be simultaneously realized by one connection.

In this embodiment, the controller 30
The computer 10 that is 0 may operate as the destination node 304. In this case, a connection is established between one source node 302 and two destination nodes 304, and object data 308 is transferred.

In this embodiment, the computer 10
Has been described as operating as the controller 300, but the computer 10 does not necessarily need to be the controller 300. The DVCR 28 or the printer 60 may operate as the controller 300.

Next, a basic transfer procedure of the communication protocol defined in the present embodiment will be described. FIG.
4A is a sequence chart illustrating a procedure up to transfer of one object data using a connection set by a certain controller 300. FIG. 3B is a sequence chart illustrating a transfer procedure when a bus reset or a transmission error occurs during transfer of one object data.

In the communication protocol of this embodiment, after a certain controller 300 sets the above-mentioned connection, one controller 300 converts one object data into one or more “Asynchronous browsing”.
adcast transaction ”. Asynchronous b
Figure 3 shows the detailed communication procedure of the roadcast transaction.
This will be described with reference to FIG.

Asynchronous broadcast transaction
Packets used in
An adcast packet will be described with reference to FIG. The above-mentioned Asynchronous broadcast transaction
And Asynchronous broadcast packet are completely new communication procedures and packet formats defined in the communication protocol of the present embodiment.

The basic transfer procedure based on the communication protocol of this embodiment will be described below with reference to FIGS. Controller 300 is the source node 3
A connection ID for identifying a logical connection relationship (connection) between the 02 and one or more destinations 304 is set. Next, the controller 300
Notifies each node of the connection ID and its own world wide unique ID, and sets one connection (401, 402 in FIG. 3A).

After the notification of the connection ID, the controller 300 instructs the source node 302 to start the transfer of the object data 308 (FIG. 3).
(A) and 403 in FIG. 4).

After receiving the instruction to start the transfer, the source node 302 sends one or more destination nodes 3
Negotiated with Asynchronous broad
Initial setting of casttransaction is performed (404 in FIG. 3A and 405 in FIG. 4).

After completing the initialization, the source node 302
Executes Asynchronous broadcast transaction and
The object data 308 consisting of one or more segment data is broadcast sequentially (406-409 in FIG. 3A and FIG. 4).

Here, the transfer model of the object data in this embodiment will be described with reference to FIG. In FIG. 7, the object data is, for example, still image data having a data size of 128 Kbytes.

The source node 302 converts the object data 308 to, for example, 50 in accordance with the receiving capability of each destination node 304 recognized in the initial setting.
0 segment data (1 segment data is 256
byte).

Here, the data size of one segment data is variably set by the source node 302 according to the size of the internal buffer of each destination node 304. FIG. 7 shows a case where an internal buffer having the same data size as the object data 308 is secured.

The source node 302 stores one or more segment data in at least one asynchronous brochure.
Transfer using adcast transaction. In FIG. 7, one segment data is transmitted by one asynchronous broadcast t.
Transfer using ransaction. After the transfer of all segment data, the source node 302 ends data communication with one or more destinations 304 (FIG. 3).
(A) and 410, 411 in FIG. 4).

Next, the operation of the controller 300 will be described in detail with reference to FIGS. The controller 300 includes the source node 30 selected by the user.
2 and one or more destination nodes 304, a packet for setting up a connection (hereinafter referred to as a packet).
Asynchronous connection setting packet)
s transfer (401, 402 in FIG. 3A). The connection ID and the world wide unique ID of the controller 300 are stored in the payload of this packet.

Next, the controller 300 sends a transmission command packet (transaction
command packet) is asynchronously transferred (403 in FIG. 3A and FIG. 4).

The source that has received the transmission command packet
The node 302 performs an initial setting using the connection ID and the world wide unique ID notified from the controller 300, and performs the asynchronous broadcast transac
is executed (404 of FIG. 3A and 404 to 40 of FIG. 4).
9). With this Asynchronous broadcast transaction, the source node 302 can sequentially transfer object data 308 including one or more segment data.

In the communication protocol of the present embodiment,
The controller 300 provides a function of managing connection connection and disconnection. Therefore, the transfer of the object data 308 after the connection is set is executed by negotiation between the source node 302 and the destination node 304.

A series of Asynchronous broadcast transacti
After the on ends, the source node 302
Asynchronous broadcast packet indicating d (segmen
(end packet) is broadcasted (410 in FIG. 3A and FIG. 4). After receiving the segment end packet from the source node 302, the controller 300
Release the connection and end the data transfer (Fig. 3
(A) and 411 in FIG. 4).

Here, since the segment end packet is broadcast, the contents of the packet can be detected at the destination node 304 as well. Therefore, the destination node 304 itself, not the controller 300,
It may be configured to release the connection with.

Next, the operation of the source node 302 will be described in detail with reference to FIGS. Source node 302 that has received a connection setting packet and a transmission command packet from controller 300
Is an asynchronous broadcast packe for requesting each destination node 304 to transfer data.
t (hereinafter, send request packet) (FIG. 3
(A) and 404 in FIG. 4).

Here, the send request packet is obtained by converting the object data 308 into an asynchronous broadcast transact.
This is a request packet for obtaining necessary initial information before executing ion. The connection ID specified by the controller 300 and the world wide unique ID of the controller 300 are written in this packet.

[0095] The destination node 304
Asynchronous broadcast packet indicating that the response corresponds to the nd request packet (hereinafter ack respo
nsepacket) (405 in FIG. 3A and FIG. 4).

Here, the ack response packet includes send
The same connection ID and world wide unique ID as the request packet are stored. Therefore, the source node 302 confirms the connection ID and the world wide unique ID of the received packet to determine which connection the ack response
Packets can be identified.

Here, in the ack response packet, the size of an internal buffer that can be secured in each destination node 304 and an offset address that specifies a predetermined memory space are stored. ack response packet
, The source node 302 sets a destination offset specifying the memory space of each destination node 304 in common, and
Start a roadcast transaction.

Here, the destination offset is equal to the ack response of each destination node 304.
This is set using the offset address included in the se packet.

In the present embodiment, Asynchronous broadca
Although the destination offset used in the st transaction is set using the offset address included in the ack response packet, the present invention is not limited to this.

For example, the controller 300 may have a function of managing the destination offset used by each connection, and may be configured to set the destination offset together with the setting of the connection ID. In this case, the destination offset corresponding to each connection is notified from the controller 300 to the source node 302.

Next, the source node 302
The asynchronous broadcast packet is written into the memory space indicated by the destination offset (406 in FIG. 3A and FIG. 4). This packet contains
Connection ID, World Wide Unique ID,
Stores the sequence number of the segment data.

After transmitting the first Asynchronous broadcast packet, the source node 302 waits for a response packet from the destination node 304. A response packet storing the connection ID, the world wide unique ID, and the sequence number is transmitted from the destination node 304 to the Asynch.
It is sent out in the form of a ronous broadcast packet. After receiving this response packet, the source node 3
02 is an asynchronous broadcast packet that increments the sequence number and includes the next segment data.
Is transferred (407 in FIG. 3A and FIG. 4).

By repeating this procedure, the source node 3
02 sequentially performs Asynchronous broadcast transaction (408 in FIG. 3A and 408 to 409 in FIG. 4). The maximum time for waiting for a response from the destination node 304 is predetermined, and if no response returns after that time, the same data is retransmitted using the same sequence number.

When a response packet requesting retransmission is transferred from the destination node 304, the source node 302 can broadcast the data of the designated sequence number again. Asynchronous b
After a roadcast transaction, source node 302
Broadcasts a segment end packet and ends data transfer (410 and 41 in FIG. 3A and FIG. 4).
1).

Here, the source node 302 divides the object data 308 into one or more segment data as necessary, as described above. The above-mentioned response packet describes each segment data as Asyn
This will occur when performing a chronous broadcast transaction. In the present embodiment, one segment data is transferred by one asynchronous broadcast transaction. The destination node 304 has a buffer having a capacity indicated by the buffer size described above.

In the above-described embodiment, the response packet is always transmitted in accordance with the asynchronous broadcast transaction of one segment data. However, the present invention is not limited to this. Destination·
The destination node 304 may transmit a response packet after the data buffer of the node 304 is filled with a plurality of continuous segment data.

Next, the operation of the destination node 304 will be described in detail with reference to FIGS. Destination node 304 that has received a connection setup packet from controller 300
Is a send request packet from the source node 302
(FIG. 3A and 404 in FIG. 4).

Upon receiving the send request packet, the destination node 304 confirms the connection ID and the world wide unique ID written in the packet, and this packet is transmitted to the source node 30.
Then, it is determined whether or not the packet is from packet 2.

Send request from source node 302
After receiving the packet, each destination node 304 wrote the connection ID, the world wide unique ID, the size of the internal buffer that can be reserved, and the offset address that specifies the predetermined memory space.
Broadcast an ack response packet (Fig. 3
(A) and 405 in FIG. 4).

Asyn transferred from source node 302
After writing the chronous broadcast packet to the memory space, the destination node 304 determines the connection ID of the packet and the world wide unique I
Confirm with D. If the connection ID and the world wide unique ID match the value set by the controller 300, a response packet (including the connection ID, the world wide unique ID, and the sequence number included in the received packet) is broadcast. (FIGS. 3A and 406 to 40 in FIG. 4)
9).

In this case, the segment data included in the received packet is stored in the internal buffer. Here, the connection ID and the world ID included in the received packet
If the wide unique ID is different from the connection ID and the world wide unique ID set for itself, the destination node 304 discards the received packet.

The destination node 304
Can detect the mismatch of the sequence numbers of the received packets and send out a response packet indicating a retransmission request. In that case, the destination node 304 notifies the source node 302 of the sequence number requesting retransmission.

All Asynchronous broadcast transacti
When on is completed, the source node 302 sends segment en
d packet is broadcast. Upon receiving this packet, the destination node 304 ends the data transfer process (41 in FIG. 3A and FIG. 4).
0).

After receiving the segment end packet, the destination node 304 broadcasts a response packet indicating that the segment end packet has been normally received (411 in FIG. 3A and 411 in FIG. 4).

As described above, the communication system according to the present embodiment can solve the inconvenience of the conventional communication system. Further, even in data transfer that does not require real-time properties, data can be transferred easily and at high speed.

In this embodiment, after the controller 300 sets the connection, the transfer processing of the object data is not controlled by the controller 300 and the source node 300 and each destination node 30 are not controlled.
4 is executed. Thus, it is possible to reduce the load on the controller 300 and provide a simple communication protocol that does not take complicated communication procedures.

In this embodiment, the destination
Node 304 transmits each Asynchronous broadcast transacti
It is configured to always return a response to on. This makes it possible to provide a communication protocol that can reliably transfer data that does not require real-time properties.

In order to realize more reliable data transfer, when data transfer is interrupted due to a bus reset or some kind of transmission error, it is necessary to restart the data transfer promptly without losing data. . Hereinafter, the restart procedure defined by the communication protocol of this embodiment will be described with reference to FIG.

For example, Asynchronou of sequence number i
s If a bus reset occurs after receiving a broadcast packet, each node suspends the transfer process and
The bus initialization, the recognition of the connection configuration, the setting of the node ID, and the like are executed in accordance with the procedures defined in the 94-1995 standard (420 and 421 in FIG. 3B).

After the completion of the bus reconstruction, each destination node 304 broadcasts a resend request packet storing a connection ID, a world wide unique ID, and a sequence number i (see FIG. 11). 422 of 3 (b)).

When the Asynchronous broadcast transaction can be resumed, the source node 302
send request packet connection ID and world
Check the wide and unique ID and ac
Broadcast k response packet (Fig. 3
(423 of (b)).

Thereafter, the source node 302 sequentially broadcasts the segment data subsequent to the sequence number requested by the received send request packet, ie, the segment data starting with the sequence number (i + 1) (FIG. 3 (b)). 424).

According to the above-described procedure, the controller 300,
Source node 302, destination node 3
04, even if the data transfer is interrupted without considering each node ID,
And it can be reliably restarted.

Further, as described above, the present embodiment has an effect that the control procedure of the controller 300 can be simplified even when the data transfer is interrupted. Next, Asynchronous broadcast packet specified in this embodiment with reference to FIG.
Will be described. Asynchronous broadcast pac
ket is, for example, 1 Quadlet (4 bytes = 3 bytes)
2 bits).

First, a packet header (packet
(header) 521 will be described. In FIG.
Field 501 (16 bits) is destination # ID
And the destination (ie, destination node 3
04). In the communication protocol of this embodiment, the asynchronous broadband of the object data 308 is used.
In order to realize a cast transaction, the value of this field is set as a broadcast ID (that is, “FFFF ₁₆ ”).

A field 502 (6 bits) indicates a transaction label (tl) field, and is a tag unique to each transaction. Field 503 (2b
Its) indicates a retry (rt) code, and specifies whether the packet attempts a retry.

A field 504 (4 bits) indicates a transaction code (tcode). tcode specifies the format of the packet and the type of transaction that must be performed. In this embodiment, the value of this field is set to, for example, “0001 ₂ ”, and a request is made to write the data block 522 of this packet into the memory space indicated by the destination_offset field 507 (ie, write transaction).

A field 505 (4 bits) indicates a priority (pri) and specifies a priority. In this embodiment, the value of this field is “0000 ₂ ”.
The field 506 (16 bits) indicates the source_ID, and indicates the node I of the transmitting side (that is, the source node 302).
D is shown.

The field 507 (48 bits) contains de
Indicates the destination_offset, and commonly specifies the lower 48 bits of the address space of each destination node 304. Here, destination_offset may be set to the same value for all connections, or may be set to a different value for each connection. However, it is better to set different values for asynchronous browsing from multiple connections.
The efficiency is high because adcast packets can be processed in parallel.

The field 508 (16 bits) contains da
ta_length, which indicates the length of a data field described later in bytes. Field 509 (16 bits)
Indicates extended # tcode. In the present embodiment, the value of this field is “0000 ₂ ”.

Field 510 (32 bits) contains he
Indicates an ader_CRC, and stores an error detection code for the fields 501 to 509 described above. Next, the configuration of the data block (datablock) 522 will be described. In the present embodiment, data block 522 includes:
Header information (packetinfor
523) and a data field (data)
field) 524.

[0132] Header information 523 includes
Logical connection relationship between each node (that is, connection)
Is stored.
Note that the configuration of the header information 523 differs depending on the purpose of use.

The data field 524 is a variable length field and stores the above-described segment data. Here, when the segment data stored in the data field 524 is not a multiple of the quadlet, “0” is filled in the portion less than the quadlet.

Field 511 (2 quadlets, 64
bits) is the world
This is a wide unique ID. The 1394 interface of the present embodiment identifies the controller 300 that has set the connection between the source node 302 and the destination node 304 by using the world wide unique ID.

Here, this world wide unique ID conforms to the IEEE 1394-1995 standard.
This is an ID unique to each node. In the present embodiment, the world wide unique ID is used as information for identifying the controller that has set each connection. However, the present invention is not limited to this. Other information may be used as long as the information can uniquely identify each node without being changed by the bus reset or the like.

The field 512 (16 bits) contains co
nnection # ID, and stores the connection ID of the present embodiment. The 1394 interface of this embodiment identifies a connection set between the source node 302 and one or more destination nodes 304 based on the connection ID stored in this field.

In this embodiment, one controller can establish 2 ¹⁶ × (the number of nodes) connections. This makes it possible to set a plurality of connections until the total amount of communication bandwidth used by each connection reaches the capacity of the transmission path.

Further, the 1394 interface of the present embodiment uses the world wide unique ID and the connection ID described above to set an absolute value between a certain source node 302 and one or more destination nodes 304. Connection can be identified.

Therefore, a plurality of controllers 300
It is also possible to set the same connection ID for two different logical connection relationships. That is, each controller is connected to the connection I set by the other controller.
It is possible to set and manage its own connection ID without worrying about D.

The field 513 (8 bits) contains prot
Indicates ocol # type and header information 523
(Ie, the type of communication protocol) based on the communication protocol. When indicating the communication protocol of the present embodiment, the value of this field is, for example, “01 ₁₆ ”.

The field 514 (8 bits) is cont
rol_flags, and predetermined control data for controlling the communication procedure and the like of the communication protocol of the present embodiment are set. In the present embodiment, the most significant bit of this field is, for example, a restart request (resend_request) flag. Therefore, when the value of the most significant bit of this field is “1”, it indicates that a restart request based on the communication protocol of this embodiment has occurred.

The field 515 (16 bits) contains
quence # number, and a continuous value (ie, sequence number) is set for a packet transferred based on a specific connection ID (the connection ID specified in the field 512).

According to the sequence number, the destination node 304 sequentially transmits the asynchronous broadband.
The continuity of the segment data that is cast transaction can be monitored. If a mismatch occurs, the destination node 304 may request retransmission based on this sequence number.

The field 516 (16 bits) contains re
Indicates confirmation # number. In this embodiment, this field is meaningful only when the value of the above-mentioned retransmission request flag is 1. For example, when the value of the above-described retransmission request flag is 1, a sequence number of a packet requested to be retransmitted is set in this field.

Field 517 (16 bits) contains bu
Indicates ffer # size. In this field, the buffer size of the destination node 304 is set. Field 518 (48 bits) is offset # add
Indicates ress. This field contains the lower 48 bits of the address space of the destination node 304.
s is stored. As a result, one of the first memory space 310 to the n-th memory space 314 shown in FIG. 2 is designated.

The field 519 (32 bits) contains da
ta_CRC, header information 523 (fields 511 to 518) as in header_CRC described above.
And an error detection code for the data field 524 are stored.

(Second Embodiment) In a second embodiment, an example will be described in which the memory space of the destination node 304 can be used efficiently even when a plurality of connections are set. In the present embodiment, the destination node 304
When the destination offset stored in the header of t specifies a predetermined address in the memory space,
The data block of the packet is directly stored in the internal buffer without being written to the memory space indicated by the address.

With this configuration, even if a plurality of connections are set for one destination node 304, the memory space of the destination node 304 can be used efficiently. Further, even when the available memory space area is limited, a plurality of connections can be set.

First, a configuration different from that of the first embodiment will be described. In the second embodiment, each node on the network has a connection ID, as shown in FIG.
It has a table that associates the destination offset with the buffer size of the internal buffer, and has a function of automatically managing them. With this function, the node serving as the destination node 304 can specify a destination offset that does not overlap with the memory space used by the already set connection.

Each node on the network is connected to the
As shown in (1), a destination offset designating a predetermined memory space 1301 is used as a pointer indicating a predetermined area 1302 on the internal buffer. Therefore, the destination node 304
Asynchronous broadca with us broadcast transaction
Write st packet directly to the internal buffer without writing it to memory space. This allows multiple Asynch
The area in the address space occupied by the ronous broadcast transaction can be significantly reduced.

Next, a transfer procedure based on the communication protocol of the second embodiment will be described with reference to FIG. The second
The communication protocol of this embodiment is basically processed in the same manner as the communication protocol of the first embodiment. Accordingly, in FIG. 9, the same processes as those in FIG.
A detailed description thereof will be omitted. The processing up to the above-mentioned connection setting is performed in the same manner as 401 to 403 in FIG. 3 (401 to 403 in FIG. 9).

After receiving the transfer start instruction, the source node 302 sets one or more destination nodes 3
A negotiation is performed with the H.04 to initialize data communication (1101, 1102 in FIG. 9).

Here, each destination node 3
04 is an ack storing the buffer size of the internal buffer and an offset address designating a predetermined memory space.
Broadcast a response packet. The source node 302 sets a destination offset that commonly specifies the memory space of each destination node 304 using the offset address included in the ack response packet.

After the initialization, the source node 302
Executes Asynchronous broadcast transaction and
The object data 308 composed of one or more segment data is sequentially broadcasted (1103 to 1103 in FIG. 9).
1106).

Here, the destination node 30
4 is each Asynchronous broadcast transaction
Write the asynchronous broadcast packet directly to the internal buffer without writing it in the memory space. After transferring all the segment data, the source node 302
The data communication with one or more destinations 304 ends (410 and 411 in FIG. 9).

As described above, in the second embodiment,
Even if a plurality of connections are set for one destination node 304, the memory space can be used efficiently. Further, even when the available memory space area is limited, a plurality of connections can be set.

(Third Embodiment) In a third embodiment, an example in which the procedure of the communication protocol of this embodiment is simplified will be described. In the third embodiment, each node on the network has a table in which a connection ID and an offset address are associated in advance. This allows
The source node 302 sends the above-mentioned send request packet to one or more destination nodes 304.
Asynchronous broadcast transac without forwarding
can be started.

First, a configuration different from that of the first embodiment will be described. In the third embodiment, each node on the network holds a table in which connection IDs and offset addresses are associated in advance as shown in FIG.

Each node refers to this table, automatically sets an offset address corresponding to the connection ID set by the controller 300, and sets Asynch
Execute ronous broadcast transaction. Here, the offset address is set to be different depending on the connection ID.

At the time of the above initial setting (404, 4 in FIG. 3)
05), the buffer size notified from one or more destination nodes 304 depends on the data transfer speed between the source node 302 and the one or more destination nodes 304 in the third embodiment. Set automatically. Each node holds a table as shown in FIG. 14 in which the data transfer speed and the maximum value of the buffer size are associated in advance, and determines an optimal buffer size according to this table.

Here, the network of this embodiment is the same as that shown in FIG.
As shown in FIG. 4, 100 Mbps, 200 Mbps,
It corresponds to 00Mbps. The maximum value of each buffer size is different depending on the data transfer speed. For example, the size is set such that the larger the data transfer speed, the larger the size.

As described above, by using a predetermined table, Asynchronous broadcast transacti
The initial setting before executing on can be omitted. This makes it possible to greatly simplify the transfer procedure and improve communication efficiency. In particular, destination 3
It is effective when the number of 04 is large.

Next, a transfer procedure based on the communication protocol of the third embodiment will be described with reference to FIG. Note that the communication protocol of the third embodiment is basically processed in the same manner as the communication protocol of the first embodiment. Therefore, FIG.
, The same processes as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, the operation of the controller 300 of the embodiment will be described in detail with reference to FIG. The controller 300 includes the source nodes 302 and 1 as in FIG.
For one or more destination nodes 304,
Asynchronous connection setting packet
Transfer (401, 402 in FIG. 12).

Next, the controller 300 sends a transmission command packet (transactio
n command packet) is transmitted asynchronously (403 in FIG. 12).

Thereafter, the above-mentioned As is described between the source node 302 and one or more destination nodes 304.
An asynchronous broadcast transaction is executed. Controller 300 receives the segmen from source node 302.
After receiving the t end packet, the connection is released and the data transfer ends (410 in FIG. 12).

Next, referring to FIG.
02 will be described in detail. Controller 30
The source node 302 that has received the connection setting packet from 0 and the transmission command packet sets the offset address using the connection ID notified from the controller 300 and the table shown in FIG. Also, the buffer size is set using the available data transfer speed and the table shown in FIG.

Next, the source node 302 uses the set offset address and the buffer size to
Generate one or more asynchronous broadcast packets and send
Execute nchronous broadcast transaction (FIG. 12)
406). Where each Asynchronous broadcast packe
In t, a connection ID and a sequence number of segment data are stored.

After transmitting the Asynchronous broadcast packet, the source node 302
It waits for a response packet from the node 304.
From the destination node 304, a response packet storing the connection ID and the sequence number is transmitted in the form of an asynchronous broadcast packet.

After receiving this response packet, the source node 302 increments the sequence number and sends the next segment data to the asynchronous node.
A us broadcast packet is transmitted (407 in FIG. 12).

By repeating the above procedure, the source node 3
02 sequentially transmits each asynchronous broadcast packet (408 and 409 in FIG. 12).

All of the object data 308 is Asynch
After performing a ronous broadcast transaction, the source node 302 broadcasts a segment end packet,
The data transfer ends (410 and 411 in FIG. 12).

Next, the operation of the destination node 304 will be described in detail with reference to FIG. The destination receiving the connection setting packet and the transmission command packet from the controller 300
The node 304 sets an offset address using the connection ID notified from the controller 300 and the table shown in FIG. Also, the buffer size is set using the available data transfer speed and the table shown in FIG.

Next, the destination node 304
Is Asynchro for the set offset address.
It waits until a nous broadcast packet is written in the above address space. Asynchronous broadcast packet
Is written in the address space, the destination node 304 checks the connection ID.

Connection ID included in received packet
Is the same as its own connection ID, the destination node 304 broadcasts a response packet storing the connection ID and the sequence number included in the received packet (40 in FIG. 12).
6-409). Here, the segment data included in the received packet is stored in an internal buffer.

After receiving the segment end packet, the destination node 304 broadcasts a response packet indicating that the segment end packet has been normally received (410 and 411 in FIG. 12).

As described above, the source node 302 of the fifth embodiment has one or more destination nodes.
Asynchronous broadcast transac without transmitting the above connection setup packet to the node 304.
can be performed. In addition, when multiple connections are synchronized with the same offset address,
Execution of a broadcast transaction can be prevented.

(Other Embodiments) The communication protocol described in each of the above embodiments and various processing operations required to realize the communication protocol can be realized by software. For example, a storage medium storing a program code for realizing the functions of the above-described embodiments may be used as a control unit (for example, the MPU 12, the system controller 50, and the printer controller 68 of FIG. ).

Then, the control unit reads out the program code stored in the storage medium, and controls the operation of the communication system or the apparatus itself so as to realize the function of each embodiment according to the program code. Even so, the above-described embodiment can be realized.

A storage medium storing a program code for realizing the functions of the above-described embodiments is supplied to the 1394 interfaces 14, 44, and 62 provided in the respective devices. A control unit for controlling the operation (for example, serial bus management 806 in FIG. 8) is configured to control the processing operation so as to realize the function of each embodiment according to the program code stored in the recording medium. You may.

In this case, the program code itself read from the above-described storage medium realizes the function of each embodiment, and the program code itself and a means for supplying the program code to the control unit (for example, , The storage medium itself) constitutes the present invention.

As a storage medium for storing such a program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, magnetic tape, nonvolatile memory card, ROM and the like can be used.

The program code read from the storage medium is stored in the operating system running on the control unit.
It goes without saying that the present invention includes a case where the functions of the respective embodiments are realized in cooperation with an (operating system) or various application software.

Further, after storing the program code read from the storage medium in the memory provided in the function expansion unit connected to the control unit, the control unit provided in the function expansion unit stores the program code in the memory. Perform some or all of the actual processing according to the stored program code,
It goes without saying that a case where the functions of the respective embodiments are realized by the processing is also included in the present invention.

The present invention can be embodied in various other forms without departing from the spirit or main characteristics. For example, in the present embodiment, IEEE1394-19
Although the communication protocol applicable to a network conforming to the 95 standard has been described, the present invention is not limited to this. The communication protocol of this embodiment is IEEE1394-199.
The present invention can also be applied to a bus-type network such as the five standards or a network that can virtually configure a bus-type network.

Therefore, the above-described embodiments are merely examples in every aspect, and should not be construed as limiting. The scope of the present invention is defined by the appended claims, and is not limited by the text of the specification. Furthermore, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

[0187]

According to the present invention, as described above, according to the present invention, a logical connection relationship independent of a physical connection form can be constructed in a bus type network such as the IEEE1394-1995 standard. .

According to another feature of the present invention, the IEEE
In a communication system compliant with the E1394-1995 standard, real-time properties are not required, but object data (for example, still image data, graphics data, text data, file data, Program data, etc.)
It is possible to provide a completely new communication protocol in which the data is divided into one or more segment data and transferred continuously.

Also, according to another feature of the present invention, I
In a communication system conforming to the IEEE 1394-1995 standard, a completely new communication protocol for realizing data communication between a plurality of devices using a communication method of asynchronously broadcasting data can be provided.

According to another feature of the present invention, the I
Isochronou of the IEEE 1394-1995 standard
A plurality of continuous data can be reliably transferred without using the s transfer method. Also, one object data can be divided into a plurality of data and transferred reliably.

Further, according to another feature of the present invention, by managing communication between a plurality of devices by one connection, it is possible to simultaneously perform a large number of communications that do not use much communication band.

Further, according to another feature of the present invention, even when data transfer is interrupted due to a bus reset or an error during transmission, it is possible to know which segment of data has been lost, and it is very complicated communication. Transfer can be resumed without taking any steps.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a communication system according to an embodiment;

FIG. 2 is a conceptual diagram illustrating a basic configuration of a communication protocol according to the first embodiment.

FIG. 3 is a sequence chart illustrating a basic communication procedure of a communication protocol according to the first embodiment.

FIG. 4 is a sequence chart illustrating a basic communication procedure of a communication protocol according to the first embodiment.

FIG. 5 Asynchronous broadcast packe of the first embodiment.
FIG. 3 is a diagram illustrating a configuration of t.

FIG. 6 is a diagram illustrating an address space of each node.

FIG. 7 is a diagram illustrating an example of a transfer model of object data according to the first embodiment.

FIG. 8 is a diagram illustrating a configuration of a 1394 interface according to the present embodiment.

FIG. 9 is a sequence chart illustrating a communication procedure of a communication protocol according to the second embodiment.

FIG. 10 is a diagram illustrating the relationship between a connection ID, an offset address, and the size of an internal buffer according to the second embodiment.

FIG. 11 is a diagram illustrating a relationship between an address space and an internal buffer.

FIG. 12 is a diagram illustrating a transfer procedure based on a communication protocol according to a third embodiment.

FIG. 13 is a diagram showing an example of a table in which connection IDs and offset addresses are associated with each other.

FIG. 14 is a diagram illustrating an example of a table in which a data transfer speed and a maximum value of a buffer size are associated in advance.

FIG. 15 is a block diagram illustrating a conventional system.

[Explanation of symbols]

 Reference Signs List 10 computer 12 arithmetic processing unit (MPU) 14 1394 interface 16 operation unit 18 decoder 20 display unit (display) 22 hard disk (HD) 24 internal memory 26 internal bus 28 camera digital video recorder 30 imaging unit (opt) 32 analog-digital (A / D) converter 34 Image processing unit 36 Compression / decompression processing unit 38 Memory 40 Memory 42 Data selector 44 Interface 50 Control unit (system controller) 52 Operation unit 54 Electronic viewfinder (EVF) 56 D / A converter 58 Recording / playback unit 60 Printer 62 1394 interface 64 Data selector 66 Operation unit 68 Printer controller 70 Decoder 72 Internal memory 74 Image processing unit 76 Driver 78 Printer head

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mitsuo Niida Canon Inc. 3- 30-2 Shimomaruko, Ota-ku, Tokyo

Claims (57)

[Claims] 1. A data communication system for performing communication using a logical connection relationship set between a transmitting device for transmitting information data and a receiving device for receiving the information data, wherein the information data The data communication system is characterized in that the memory space for storing the data is different for each logical connection relationship. 2. The data communication system includes a management device having a function of managing the logical connection relationship, and the management device connects the transmission device and the reception device in a logical connection relationship. The data communication system according to claim 1, wherein: 3. The data communication system according to claim 2, wherein the management device notifies the transmitting device and the receiving device of information for identifying the logical connection relationship. 4. The information for identifying the logical connection relationship includes Asynch compliant with the IEEE 1394 standard.
The data communication system according to claim 3, wherein the notification is made using a robust transfer method. 5. The data communication system according to claim 1, wherein memory spaces corresponding to respective logical connection relationships do not overlap. 6. The transmitter and the receiver have a table in which the logical connection relationship is associated with an offset address indicating a predetermined area of the memory space, and the information data is stored using the table. The data communication system according to any one of claims 1 to 5, wherein a memory space to be selected is selected. 7. The data communication system according to claim 1, wherein a size of said memory space varies according to a transfer speed of said information data. 8. The data communication system according to claim 1, wherein the information data is broadcast. 9. The information processing apparatus according to claim 1, wherein the information data is transferred using an Asynchronous transfer method based on the IEEE 1394 standard.
A data communication system according to item 9. 10. The data communication according to claim 1, wherein the information data is transmitted using a communication packet including information for identifying the logical connection relationship. system. 11. The data communication system according to claim 2, wherein the management device can set one or more logical connection relationships between a pair of transmission device and reception device. 12. The data communication system according to claim 2, wherein the management device can set one or more logical connection relationships between one transmitting device and a plurality of receiving devices. 13. The management device includes a plurality of transmission devices and one
3. The data communication system according to claim 2, wherein one or more logical connection relationships can be set between two receiving devices. 14. The data communication system according to claim 2, wherein the management device can set one or more logical connection relationships between a plurality of transmission devices and a plurality of reception devices. 15. The data communication system according to claim 1, wherein the logical connection specifies a predetermined memory space of the receiver. 16. The data communication system according to claim 1, wherein a different area is designated in said memory space for each of said logical connection relationships. 17. The data communication according to claim 2, wherein the release of the logical connection between the transmitting device and the receiving device is performed by the management device or the receiving device. system. 18. The data communication system according to claim 1, wherein said receiving device is provided with a bit indicating that data has been normally received. 19. The data communication system according to claim 1, wherein the transmitting device measures a response from the receiving device for a predetermined period, and detects a communication abnormality based on the period. 20. The data communication system according to claim 19, wherein, when detecting the communication abnormality, the transmitting device automatically starts an operation of retransmitting information data to the receiving device. 21. A data communication system using a communication system for continuously and asynchronously transmitting a plurality of communication packets, wherein information transmitted by the communication system is in the same area of a memory space of the plurality of devices. A data communication system characterized by being stored in a data communication system. 22. The data communication system according to claim 21, wherein said communication packet is broadcast. 23. The data communication system according to claim 21, wherein a size of an area of a memory space for storing information transmitted by the communication method varies according to a data communication speed. 24. A data communication system comprising a plurality of devices, wherein communication between a plurality of different devices is determined by a plurality of different ID information, and information transmitted by the communication corresponds to the ID information. A data communication system storing data in a plurality of different memory spaces. 25. The data communication system according to claim 24, wherein the ID information includes a connection ID indicating a logical connection relationship between the plurality of different devices. 26. The memory device according to claim 24, wherein a size of a memory space for storing information transmitted by communication of the plurality of devices differs according to a data transfer speed of the communication.
Or the data communication system according to 25. 27. A data communication device connectable to a communication system constituted by a plurality of devices, comprising: a logical device set between a transmitting device for transmitting information data and a receiving device for receiving the information data. A data communication apparatus comprising: a communication unit that performs communication using a logical connection relationship; and a storage unit that stores a memory space for storing the information data in association with the logical connection relationship. 28. A data communication system including a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing communication of the information data, wherein the transmitting device and the receiving device After the device and the management device set a logical connection relationship between the transmission device and the reception device, the transmission device transmits the information data to a memory space corresponding to the logical connection relationship. A data communication system, comprising: 29. A data communication method for performing communication using a logical connection relationship set between a transmitting device for transmitting information data and a receiving device for receiving the information data, the data communication method comprising: A data communication method for storing the information data in different memory spaces according to different connection relationships. 30. A data communication method using a communication system for continuously and asynchronously transmitting a plurality of communication packets, wherein information transmitted by the communication system is stored in the same area of a memory space of the plurality of devices. A data communication method characterized by storing 31. A data communication method applicable to a data communication system constituted by a plurality of devices, wherein a communication between a plurality of different devices is identified by a plurality of different ID information, and information transmitted by the communication is determined. In a plurality of different memory spaces corresponding to the ID information. 32. A data communication method applicable to a data communication system including a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing communication of the information data. After controlling the transmitting device, the receiving device, and the management device so as to set a logical connection relationship between the transmitting device and the receiving device, a memory space corresponding to the logical connection relationship To transmit the information data to
A data communication method comprising controlling the transmitting device. 33. A source node for transferring data comprising one or more segments using at least one asynchronous communication, one or more destination nodes for receiving data transferred from the source node, A data communication system, comprising: a controller that sets a logical connection relationship between a source node and the one or more destination nodes. 34. The data communication system according to claim 33, wherein the source node transfers the data based on a logical connection relationship with the one or more destination nodes. 35. The data communication system according to claim 33, wherein the source node performs the at least one asynchronous communication continuously. 36. The one or more destination nodes according to claim 33, wherein the one or more destination nodes transfer the data based on a logical connection relationship with the source node. A data communication system according to claim 1. 37. The method according to claim 33, wherein the one or more destination nodes return a response to data transferred using the asynchronous communication.
7. The data communication system according to any one of 6. 38. The controller according to claim 33, wherein the controller can set one or more logical connection relationships between the source node and the one or more destination nodes. The data communication system according to claim 1. 39. The logical connection according to claim 33, wherein the logical connection is released by the controller or the destination node after the transfer of the data.
38. The data communication system according to any one of the items 38. 40. The data communication system according to claim 33, wherein an initialization necessary for transferring the data is performed between the source node and the one or more destination nodes. The data communication system according to claim 1. 41. The data communication system according to claim 40, wherein said controller can set a part of initial information set in said initial setting. 42. The data communication system according to claim 40, wherein the one or more destination nodes notify the source node of initial information necessary for the initial setting. 43. The data communication system according to claim 40, wherein the source node performs the initial setting using initial information notified from the one or more destination nodes. 44. In the initial setting, at least one of a destination node address for specifying a memory space of the one or more destinations and a receiving buffer size is set. 44. The data communication system according to any one of -43. 45. The data communication system according to claim 33, wherein the source node broadcasts the data using the asynchronous communication. 46. The method according to claim 33, wherein the source node writes the data to a common memory space of the one or more destinations using the asynchronous communication. A data communication system according to claim 1. 47. The data communication according to claim 33, wherein the one or more destination nodes store the data in a common memory space of the destination node. system. 48. The asynchronous transfer according to IEEE 1394
48. The method according to any one of claims 33 to 47, which is based on an Asynchronous transfer system of the -1995 standard.
A data communication system according to item 9. 49. The data communication system according to claim 33, wherein said data communication system is a bus type network. 50. The data communication system according to claim 50, wherein:
50. The data communication system according to any one of claims 33 to 49, wherein the data communication system is a network based on the 1394-1995 standard. 51. The data according to claim 33, wherein the data comprising one or more segments is at least one of still image data, file data, and program data. Communications system. 52. establishing a logical connection relationship between a source node and one or more destination nodes; and transmitting the data comprising one or more segments using at least one asynchronous communication. A data communication method, comprising: transferring data to one or more destination nodes; and receiving data transferred using the asynchronous communication using the logical connection relationship. 53. A source node for transferring data comprising one or more segments using at least one broadcast, and one or more destination nodes for receiving data transferred from the source node. The source node and the one or more destination nodes manage the data transfer based on a logical connection relationship set between the source node and the destination node. Data communication system. 54. Establishing a logical connection between a source node and one or more destination nodes; and transmitting the data comprising one or more segments using at least one broadcast communication. A data communication method, comprising: transferring data to one or more destination nodes; and receiving data transferred using the broadcast communication based on the logical connection relationship. 55. A means for packetizing data consisting of one or more segments into at least one communication packet, and said communication packet using a logical connection relationship established between one or more destination nodes. Means for asynchronously transferring the data. 56. A means for receiving at least one communication packet asynchronously transferred using a logical connection relationship established with a source node, and sharing data included in the communication packet with another device. Means for writing to a memory space of the digital interface. 57. A means for setting a logical connection between a source node and one or more destination nodes, and a connection I for identifying the logical connection.
Means for notifying D to the source node and the one or more destination nodes.