JP2000032010A - Data communication system, data communication method, data communication device, digital interface and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid deterioration in the transmission efficiency by reducing a time to restart a transfer and a data quantity to be duplicated and transferred. SOLUTION: In the data communication system that includes a source 402 that transmits information data, a destination 403 that receives the information data, and a controller 401 that manages communication between the source 402 and the destination 403, the controller 401 inquires of the source 402 about the transmitted parts of the data after a bus is reset, and the controller 401 instructs the source 402 to re-transmit according to the result of the inquiry, and the destination 403 does not clear contents already received in a buffer at resetting so as to reduce a time required to restart the transfer and reduce the data quantity to be duplicated and transferred.

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, a digital interface, and a storage medium, and more particularly, to a high-speed operation by mixing information data (including image data) and command data. The present invention relates to a communication network and a communication protocol technology 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.

The conventional dedicated interface or SCSI interface has a low data transfer rate and a thick communication cable for parallel communication, especially when handling a large amount of data such as a still image or a moving image of an AV device. There have been many problems such as a limited number and types of peripheral devices that can be performed, limitations on connection methods, and inability to perform real-time data transfer.

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

A digital interface (hereinafter, referred to as a 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.

[0007]

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.

[0008] 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 is not specified.
There is no guarantee that the ous packet has been received reliably.
Therefore, if it is desired to reliably transfer a plurality of continuous data, or if one file data is to be divided into a plurality of data and transferred reliably, Isochrono is used.
Us transfer method could not be used.

[0009] Also, 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.

In 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, and 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.

Further, in a communication system conforming to the IEEE 1394-1995 standard, object data (for example, still image data, graphics data, text data, etc.) which does not require real-time processing but requires a relatively large amount of reliability. , File data, program data, etc.) has not been specifically proposed for dividing the data into one or more segment data and continuously transferring the data.

In such a communication system, when a bus reset occurs, the segment being transferred must be restarted from the beginning. In particular,
If the destination buffer capacity is large and most of the segments have been transferred,
There is a problem that it takes time to restart the transfer, and the same data is transferred uselessly.

In order to solve the above-mentioned problem, it is conceivable to set a small destination buffer size in advance to reduce the amount of discarded data and the amount of retransmitted data. However, even in such a configuration, there is a problem that communication of a control command transferred in segment units and a response to the control command increase, and transmission efficiency deteriorates.

[0015] In view of the above background, an object of the present invention is to provide a data communication system and a data communication method which reduce the time required for resuming the transfer and the amount of data transferred redundantly and which do not reduce the transmission efficiency. , A data communication device, a digital interface and a storage medium.

[0016]

SUMMARY OF THE INVENTION A data communication system according to the present invention includes a source for transmitting information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. In the data communication system including, the transmission of the information data interrupted due to the initial setting of the network,
Based on negotiations between the source and the destination, the information data is restarted from a part of the information data. Another feature of the data communication system of the present invention is that a source for transmitting the information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. In the data communication system including the above, transmission of the information data interrupted due to network initialization is restarted from a part of the information data based on negotiation between the controller and the source. . Another feature of the data communication system of the present invention is that a source that transmits information data, a destination that receives the information data, and a controller that manages communication between the source and the destination. In the data communication system including, the information data interrupted transmission due to the initial setting of the network, to specify between the source and the destination, to resume transmission from the specified information data Features. Another feature of the data communication system of the present invention is that a source for transferring information data by using an address designating a part of a memory space of the destination, and a memory space designated by the address. A destination that stores the information data, and a controller that manages data transfer between the source and the destination, wherein the transfer of the information data is interrupted in accordance with the initial setting of the network. In this case, the transfer is restarted from a part of the information data using the address managed by the source. Another feature of the data communication system of the present invention is that a source for transferring information data by using an address designating a part of a memory space of the destination, and a memory space designated by the address. A destination that stores the information data, and a controller that manages data transfer between the source and the destination, wherein the transfer of the information data is interrupted in accordance with the initial setting of the network. In this case, the transfer is restarted from a part of the information data using the address specified by the destination.

A data communication method according to the present invention includes a source for transmitting information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. Wherein the transmission of the information data interrupted due to network initialization is restarted from a part of the information data based on negotiation between the source and the destination. And Another feature of the data communication method of the present invention is a data communication method applicable to a data communication device for transmitting information data to a destination, wherein the data communication method includes a predetermined area of a memory provided in the destination. , And a part of the information data to be transmitted is selected by using the first information designating the information and the second information notified from the destination after the initial setting of the network. Another feature of the data communication method of the present invention is a data communication method applicable to a data communication device that receives information data transmitted from a source, wherein the information data is transmitted after initial setting of a network. The source is notified of an address designating a memory space in which a part of is stored. Another feature of the data communication method of the present invention is a data communication method applicable to a data communication device for transmitting information data to a destination, wherein a predetermined amount of memory space of the destination is provided. Information data to be transmitted using first information specifying an area and second information specifying a memory space in which a part of the information data whose transmission has been interrupted after network initialization is stored. Is selected. Another feature of the data communication method of the present invention is a data communication method applicable to a data communication device that receives information data transmitted from a source, wherein reception is interrupted after network initialization. It is characterized in that control is performed so as to wait for a part of the information data transmitted from the source without discarding the information data. Another feature of the data communication method of the present invention is that, in a data communication method applicable to a data communication device in which communication with a destination is managed by a controller, transmission is resumed after initial setting of a network. An address for designating a memory space for storing data is notified to the controller, and transmission from data corresponding to the address is restarted in response to an instruction from the controller. Further, other features of the data communication method of the present invention include a source for transmitting information data,
In a data communication method applicable to a data communication system including a destination for receiving the information data and a controller for managing communication between the source and the destination, the data communication method is interrupted due to network initialization. The transmission of the data is restarted from a part of the information data based on negotiation between the source and the controller. Another feature of the data communication method of the present invention is that a source for transmitting the information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. In a data communication method applicable to a data communication system including, the information data whose transmission has been interrupted due to the initial setting of a network, is specified between the source and the destination, and the specified information data is specified. It is characterized in that the transfer is restarted from. Another feature of the data communication method of the present invention is that the step of transferring information data by using an address designating a part of the memory space of the destination comprises the steps of: Storing the information data in a part of the information data, and transferring the information data from a part of the information data using an address managed by a source when the transfer of the information data is interrupted due to network initialization. And restarting. Another feature of the data communication method of the present invention is that, using an address designating a part of a memory space of the destination, the step of transferring information data;
When the transfer of the information data is interrupted due to the initial setting of the network, a step of restarting the transfer from a part of the information data using an address managed by the source. Another feature of the data communication method of the present invention resides in that the information data transferred from the source is stored in a part of a memory space designated by the source, and the information is transmitted along with the initial setting of the network. And restarting the transfer from a part of the information data without notifying an address necessary for restarting the transfer of the information data when the transfer of the information data is interrupted. . Another feature of the data communication method according to the present invention is that, in addition to the step of notifying the source of an address designating a part of the memory space of the destination and instructing the start of transfer of information data, When the transfer of the information data is interrupted due to the initial setting of the network, the transfer is restarted from a part of the information data without notifying the address necessary for resuming the transfer of the information data. And the step of performing the control. Another feature of the data communication method of the present invention is that the step of transferring information data by using an address designating a part of the memory space of the destination comprises the steps of: Storing the information data in a part of the information data, and when the transfer of the information data is interrupted due to the initial setting of the network, a part of the information data is used by using an address designated by the destination. And restarting the transfer. Also,
Other features of the data communication method of the present invention include a step of transferring information data using an address designating a part of a memory space of the destination, and a step of transferring the information in accordance with an initial setting of a network. And restarting the transfer from a part of the information data using the address specified by the destination when the transfer of the data is interrupted. Another feature of the data communication method of the present invention resides in that the information data transferred from the source is stored in a part of a memory space designated by the source, and the information is transmitted along with the initial setting of the network. And when the transfer of the information data is interrupted, notifying the source of an address designating a part of the memory space. Another feature of the data communication method according to the present invention is that, in addition to the step of instructing the source to specify an address specifying a part of the memory space of the destination, the step of instructing the start of the transfer of information data. When the transfer of the information data is interrupted due to the initial setting of the network,
And instructing the source to notify the source of an address designating a part of the memory space.

[0018] The data communication apparatus of the present invention comprises: a transmitting means for transmitting information data to a destination; a storing means for storing first information specifying a predetermined area of a memory provided in the destination; a bus reset; And selecting means for selecting a part of the information data to be transmitted, using the second information notified from the destination and the first information in response to the first information. Another feature of the data communication device of the present invention is that a receiving unit for receiving information data transmitted from a source and a memory space in which a part of the information data is stored after initial setting of a network. And notifying means for notifying the specified address to the source. Another feature of the data communication device of the present invention is that a transmitting unit for transmitting information data to a destination and first information for specifying a predetermined area of a memory provided in the destination are stored. After the storage means and network initialization,
Selecting means for selecting a part of the information data to be transmitted using second information specifying a memory in which a part of the information data whose transmission has been interrupted is stored and the first information; It is characterized by doing. Further, other features of the data communication device of the present invention, the receiving means for receiving information data transmitted from the source, after the initial setting of the network, without discarding the information data interrupted reception, And control means for controlling to wait for a part of the information data transmitted from the source. Another feature of the data communication device of the present invention is that, in a data communication device in which communication with a destination is managed by a controller, a memory space for storing data for interrupting transmission after network initialization is set. It is characterized by comprising a notifying means for notifying the specified address to the controller, and a transmitting means for restarting transmission from data corresponding to the address in response to an instruction from the controller. Another feature of the data communication device of the present invention is that a transmitting unit that transmits information data to a destination and information data whose transmission is interrupted by a bus reset are specified between the destination and the transmitting unit. And control means for performing control so as to restart the transfer from the specified information data. Another feature of the data communication device of the present invention is that the data communication device uses an address for designating a part of the memory space of the destination and transfers information data, and the network is initialized. Means for controlling, when the transfer of the information data is interrupted, to restart the transfer from a part of the information data by using a managed address. Another feature of the data communication device of the present invention is that information data transferred from a source is
Means for storing the information data in a part of a memory space designated by the source, and notifying an address necessary for resuming the transfer of the information data when the transfer of the information data is interrupted due to initialization of the network. Means for controlling so as to restart the transfer from a part of the information data without performing the operation. Another feature of the data communication device of the present invention is that the data communication device uses an address for designating a part of the memory space of the destination and transfers information data, and the network is initialized. Means for controlling, when the transfer of the information data is interrupted, to restart the transfer of the information data from a part of the information data by using an address designated by the destination. Another feature of the data communication device of the present invention resides in that information data transferred from a source is stored in a part of a memory space designated by the source, and the information is transmitted along with the initial setting of a network. Means for notifying the source of an address designating a part of the memory space when the transfer of the information data is interrupted. Further, another feature of the data communication device of the present invention is that, in addition to means for notifying the source of an address designating a part of the memory space of the destination and instructing the start of information data transfer, When the transfer of the information data is interrupted due to the initial setting of the network, control is performed such that the transfer of the information data is resumed without discarding a part of the data stored in the memory space. Means. Further, another feature of the data communication device of the present invention is that, in addition to the means for instructing the source to specify an address specifying a part of the memory space of the destination and the means for instructing the start of the transfer of information data, Means for instructing the source at an address specifying a part of the memory space when the transfer of the information data is interrupted due to the initial setting of the network.

According to the digital interface of the present invention, a step of transferring information data by using an address designating a part of a memory space of a destination, and a step of interrupting the transfer of the information data with initial setting of a network And a step of restarting transfer from a part of the information data using an address managed by the source when the data communication is performed. Another feature of the digital interface of the present invention is that information data transferred from a source is
Storing the data in a part of the memory space specified by the source; and notifying an address necessary for resuming the transfer of the information data when the transfer of the information data is interrupted due to initialization of the network. Without restarting, the step of restarting the transfer from a part of the information data. Also,
Another feature of the digital interface of the present invention is that a source is notified of an address designating a part of a memory space of a destination, and a command to start transfer of information data is provided. When the transfer of the information data is interrupted due to the initial setting, control is performed such that the transfer is restarted from a part of the information data without notifying an address necessary for resuming the transfer of the information data. The method is characterized in that a data communication method for performing the steps can be realized. Also,
Other features of the digital interface of the present invention include: means for transferring information data using an address designating a part of a memory space of the destination; Means for restarting the transfer from a part of the information data by using the address designated by the destination when the transfer of the information data is interrupted. Another feature of the digital interface of the present invention is that the information data transferred from the source is stored in a part of the memory space designated by the source, and the information is transmitted along with the initial setting of the network. Means for notifying the source of an address designating a part of the memory space when the transfer of the information data is interrupted. Another feature of the digital interface of the present invention is that, in addition to the source, an address for designating a part of the memory space of the destination, and a means for instructing the start of information data transfer, Means for instructing the source to notify the source of an address specifying a part of the memory space when the transfer of the information data is interrupted due to network initialization. It is characterized by doing.

A storage medium according to the present invention is a data communication system including a source for transmitting information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. A computer reads a program for realizing a function of restarting transmission of the information data interrupted due to network initialization from a part of the information data based on negotiation between the source and the destination. It is characterized by being memorized as possible. Another feature of the storage medium of the present invention is that, in a data communication device in which communication with a destination is managed by a controller, a memory space for storing data to resume transmission after network initialization is designated. A program for realizing a function of notifying the controller of an address to be transmitted and restarting transmission from data corresponding to the address in accordance with an instruction from the controller, the program being stored in a computer-readable manner. . Other features of the storage medium of the present invention include a source for transmitting information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. In the data communication system including, based on the negotiation between the source and the controller, to realize the function of restarting the transmission of the information data interrupted due to the initial setting of the network from a part of the information data The program is stored in a computer-readable manner. Other features of the storage medium of the present invention include a source for transmitting information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. In a data communication system including: a function of identifying information data whose transmission has been interrupted due to network initialization between the source and the destination, and restarting transfer from the identified information data. The program is stored in a computer readable manner.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a data communication system, a data communication method, a data communication device and a storage medium according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating the configuration of the communication system according to the present embodiment. In FIG. 1, each device includes a digital interface 105 that conforms to the IEEE 1394-1995 standard (hereinafter, 1394 standard).

The communication system shown in FIG. 1 includes a TV 101, a digital video tape recorder (hereinafter, DVTR) 102,
Printer 103, digital camcorder (hereinafter DVC)
R) 104.

In FIG. 1, TV 101, DVTR 10
2. The DVCR 104 includes a control unit 106, a signal processing unit 10
7, and the printer 103 includes a control unit 106 and an image processing unit 109. Each device is connected via a communication cable conforming to the 1394 standard.

Here, there are two types of communication cables: a 4-pin cable and a 6-pin cable. The 4-pin cable is composed of two pairs of shielded twisted pairs used for data transfer and arbitration signal communication. The 6-pin cable includes two twisted pairs and a pair of power supply wires. The data transmitted using the two twisted pairs is D
This is data encoded by the S-Link method.

Next, the configuration of the digital interface 105 of this embodiment will be described in detail with reference to FIG. The digital interface 105 is functionally composed of a plurality of layers (layers). In FIG. 2, a digital interface 105 is an IEEE1394-1995
It is connected to a digital interface 105 of another device via a communication cable 201 conforming to the standard. Also, the digital interface 105 has one or more communication ports 2.
02, and each communication port 202 is connected to a physical layer 203 included in the hardware unit.

In FIG. 2, the hardware section is composed of a physical layer 203 and a link layer 204. The physical layer 203 includes a physical and electrical interface with another node, detection of a bus reset and processing accompanying the reset, encoding / decoding of input / output signals,
Arbitrates the right to use the bus. Also, the link layer 204
Performs generation of communication packets, transmission and reception of various communication packets, control of a cycle timer, and the like. The link layer 204 provides a function of generating, transmitting, and receiving packets specified in a communication protocol described later.

In FIG. 2, the firmware section
It includes a transaction layer 205 and a serial bus management 206. The transaction layer 205 manages the asynchronous transfer system and provides various transactions (read, write, lock).

Also, the transaction layer 205
It provides a function to manage transactions specified in a communication protocol described later. The serial bus management 206 controls the own node, manages the connection state of the own node, and manages the connection state based on the IEEE1212 CSR standard.
It provides functions for managing ID information of its own node and managing resources of the serial bus network. The serial bus management 206 provides a function of controlling various processing operations related to a communication protocol described later.

The hardware section and the firmware section shown in FIG. 2 substantially constitute a 1394 interface, and their basic configuration is based on IEEE1394-1.
995 standard.

The application layer 207 included in the software section differs depending on the application software used, and controls what object data is transferred and how.

A communication protocol according to the present embodiment, which will be described later, extends the functions of the hardware unit and the firmware unit constituting the digital interface 105, and provides a new transfer procedure to the software unit.

In the digital interface 105, when the power is turned on, a bus reset is automatically performed according to a change in the connection configuration such as connection or disconnection of a new device. Here, the bus reset means that each device (hereinafter, a node) constituting the communication system has a connection configuration of the communication system and a communication address of each device (hereinafter, a node I) which have been recognized up to now.
D) is performed to perform re-recognition of a new connection configuration and resetting of a communication address.

Hereinafter, the processing procedure of the bus reset will be briefly described. This procedure consists of recognizing a hierarchical connection configuration in a communication system and assigning a physical communication address to each node.

Recognition of the connection configuration is executed by each node declaring a parent-child relationship after the start of the bus reset. Each node recognizes the communication system as a tree structure (hierarchical structure) by determining a parent-child relationship between the nodes. Note that the parent-child relationship between the nodes depends on the connection state of the communication system and the function of each node, and therefore does not become the same every time the bus is reset.

For example, in the communication system shown in FIG.
3 (hereinafter, node D) and a parent / child relationship are set between the DVTR 102 (hereinafter, node C). Next, DVCR10
4 (hereinafter, node B) and TV 101 (hereinafter, node A)
, And between the node C and the node A.

Finally, the parent (or higher order) of all nodes
The device recognized as a root node manages arbitration of the right to use the bus of the communication system. In the communication system of FIG. 1, node A is the root node.

After the determination of the root node, each node constituting the communication system automatically starts setting a node ID. The setting of the node ID is basically such that the parent node allows the setting of the physical address to the child node connected to the communication port having the lower port number, and the child node sequentially sets the physical address to its own child node. Performed by giving permission. The node that has set its own node ID is
The self-ID packet is transmitted, and the node ID assigned to itself is notified to other nodes. After the ID setting of all the child nodes is completed, the parent node sets its own node ID.

By repeatedly executing the above processing, the node ID of the root node is set last. Since the node ID assigned to each node depends on the parent-child relationship of each device, the same node ID is not set every time the bus is reset.

Next, an automatic node ID setting process will be described with reference to FIG. In the following description, a case where the node A becomes the root node after the recognition of the connection configuration will be described.

In FIG. 1, node A, which is the root node, first permits the node connected to the communication port of "port 1", that is, node B, to set the node ID.

The node B sets its node ID to "# 0".
, And the result is broadcast as a self-ID packet to all nodes constituting the communication system. Here, the broadcast means transmitting predetermined information to an unspecified number of nodes as destinations.

As a result, all nodes have the “node ID”
"# 0" is already allocated ", and the node permitted to set the node ID sets"# 1 ". After the setting of the node B, the node A sends the node I to the node connected to the communication port of "port 2",
Allow setting of D.

The node C further gives the setting permission in order from the communication port with the smallest port number among the communication ports to which the child nodes are connected. That is, permission is given to the node D, and the permitted node D has the node ID
After setting “# 1”, a self ID packet is broadcast.

After the setting of the node D, the node C sets its own node ID to "# 3", and finally the node A, which is the root node, sets its own node ID to "# 4". End recognition of.

By such a bus reset process, the digital interface 105 of each node can automatically recognize the connection configuration of the communication system and set the communication address of each node. Each node can perform communication between the nodes by using the above-described node ID.

Next, a data transfer method provided in the digital interface 105 will be described with reference to FIG. The communication system shown in FIG.
It has a hronous transfer mode and an asynchronous transfer mode. The isochronous transfer mode is effective for real-time transfer of video data and audio data because it guarantees transmission and reception of a fixed amount of packets every communication cycle period (125 μs). Asynchronous transfer mode is
This is a transfer mode in which control commands, file data, and the like are asynchronously transmitted and received as necessary. The priority is set lower than in the isochronous transfer mode.

In FIG. 3, at the beginning of each communication cycle, a communication packet called a cycle start packet 301 for adjusting the cycle time measured by each node is transmitted.

After the transfer of the cycle start packet 301, a predetermined period is set to the isochronous transfer mode. In the isochronous transfer mode, a plurality of isochronous transfers can be executed by assigning a channel number to each of the data transferred based on the isochronous transfer mode.

For example, in FIG. 3, the data 302 transferred isochronously from the DVCR 104 has a channel number "ch0", the data 303 transferred isochronously from the DVTR 102 has a channel number "ch1", and the TV 101
When the channel number “ch2” is assigned to the data 304 that is transferred isochronously from
Isochronous transfer is performed in a time division manner within one communication cycle period.

After the completion of each isochronous transfer, a period until the next cycle start packet 301 is transferred is used for asynchronous transfer. For example, in FIG. 3, the data 305 based on the asynchronous transfer is a DVCR.
The data is transferred from the printer 104 to the printer 103.

FIG. 4 is a sequence chart for explaining the basic configuration of the communication protocol of the present embodiment using the asynchronous transfer mode. In FIG. 4, the node 402 that sequentially transfers object data, for example, a still image, asynchronously, that is, the source 402 is the DVCR 104. The node that receives the object data asynchronously transferred from the source 402, that is, the destination 403 is the printer 103. Further, the node that manages the communication between the source 402 and the destination 403, that is, the controller 401 is the TV 101.

The communication protocol according to the present embodiment has three phases. The first phase 404 is a connection phase, in which the controller 401 inquires about the reception buffer size of the destination 403, a destination offset described later, and whether or not reception is possible, and sets the destination 403 in a reception standby state. Further, the controller 401
02, object data to be asynchronously transferred is selected, and the source 402 is set in a transfer standby state.

The second phase 405 is a transmission phase, in which the controller 401 controls the source 402 and the destination 403, and stores
Asynchronous transfer is sequentially performed by one or more packets.

The third phase 406 is a connection release phase, in which the controller 401 releases the reception buffer of the destination 403 from its own control, and similarly releases the transmission buffer of the source 402 from its own control.

FIG. 5 shows object data and destination 4 asynchronously transferred from the source 402.
FIG. 11 is a diagram for explaining a relationship with a reception buffer of No. 03. The object data 501 asynchronously transferred from the source 402 is equal to the reception buffer size of the destination 403 notified from the controller 401 and is equal to 1
It is divided into one or more segments 502.

The data included in each segment 502 includes a communication packet 503 based on one or more asynchronous transfer modes (hereinafter referred to as an asynchronous packet 50).
The packet is packetized in 3) and is sequentially transferred from the source 402 to the destination 403.

The destination 403 is the source 4
02, sequentially receive Asynchronous packets 503 from
The data is temporarily written to the reception buffer 504. After the transfer of the object data for one segment is completed, the destination 403 sequentially writes the data for one segment stored in the reception buffer 504 to the internal memory 505.

Next, referring to FIG. 6, the reception buffers 50 of all the nodes including the destination 403 will be described.
4 will be described in detail. The reception buffer 504 has I
EEE1212CSR (Control and St)
atus RegisterArchiectur
e) Standards (or ISO / IEC 13213: 1994)
Standards) and is managed by a 64-bit address space. The IEEE1212 CSR standard is a standard that specifies control, management, and address allocation for a serial bus.

FIG. 6A shows a logical memory space represented by a 64-bit address. FIG. 6 (b)
Is part of the address space shown in FIG. 6 (a), for example, an address space the upper 16 bits are FFFF _16. The reception buffer 504 uses a part of the address space shown in FIG. 6B and is designated by a destination offset indicating the lower 48 bits of the address.
This destination offset is calculated for each Async.
Specified by the header part of the Hronous packet.

In FIG. 6B, for example, 00000
00000000 _{16 to} 000000003FF ₁₆ are reserved areas, and in the area where the object data 501 is actually written, the lower 48 bits of the address are FF.
FFF0000400 ₁₆ or later to become the region.

(First Embodiment) Hereinafter, a case where the communication protocol of the first embodiment is applied to the communication system shown in FIG. 1 will be described. Here, the controller 401 in the first embodiment is the TV 101 and the source 4
02 is the DVCR 104, and the destination 403 is the printer 103.

In the first embodiment, the source 402
As shown in FIG. 5, after one object data (for example, image data, audio data, graphics data, text data, etc.) 501 is divided into one or more segments 502, each segment 502 is divided into one or more segments 502. of
Asynchronous transfer is performed using an asynchronous packet 503. The destination 403 is the source 40
One or more Asynchronous transferred asynchronously from 2
The packet 503 is written into the reception buffer 504 and stored in the internal memory 505 for each segment 502.

Further, the controller 401 inquires of the buffer size of the destination 403,
Selection of object data transferred from 2, source 4
The communication between the source 402 and the destination 403 is managed, such as designation of the size of the segment generated at step 02.

As shown in FIG. 4, the communication protocol according to the first embodiment includes three phases, namely, a connection phase, a transmission phase, and a connection release phase.

Here, the connection phase and the connection release phase in the first embodiment
First phase 404, third phase 40 shown in FIG.
6 can be performed. Therefore, in the first embodiment, the transmission phase will be described in detail.

FIG. 7 is a sequence chart for explaining in detail the transmission phase of the first embodiment. In FIG. 7, the controller 401 sends an Asynch message to the destination 403 with some communication packets.
It instructs to receive one segment of data transferred by ronous (704). Also, the controller 401
The source 402 is instructed to divide the object data into one or more segments, and to transfer each segment asynchronously with several communication packets (70).
5).

Here, source 4 from controller 401
The configuration of the command transferred to the H.02 will be described with reference to FIG. This command is, for example, a command for instructing the source 402 to start transfer of one segment (hereinafter, a transfer start command), and is transferred in the asynchronous transfer mode.

In FIG. 8, the first field 801 stores command data for instructing the start of transfer and the like. A field 802 stores a segment number indicating the order of segments to be transmitted. Field 8
In 03, the node ID of the destination 403 is stored.

The field 804 stores the start address of the reception buffer 504 of the destination 403. The field 805 stores the size of the reception buffer included in the destination 403, that is, the size information of one segment. Field 806 stores the maximum size information of the communication packet that can be received by destination 403. A field 807 stores various status information and the like.

In FIG. 8, a predetermined area of field 807 has an area 808 for storing retransmission identification bits.
Is set. The source 402 reads this area 808 to determine whether to perform normal transfer processing or retransmission processing. For example, the controller 401
However, when instructing the source 402 to transfer a normal segment, “0” is stored in this area 808.

In the first embodiment, the source 402 that has received the transfer start command is configured to store the value of the start address of the reception buffer 504 stored in the field 804 in a predetermined internal register. Here, the internal register is the digital interface 105 included in each device or the control unit 1 that controls the operation of each device.
06 (see FIG. 1).

In FIG. 7, after an instruction from the controller 401, the source 402 packetizes one segment 502 into one or more asynchronous packets 503, and
Destination 4 of Asynchronous packet 503
03 sequentially (706).

Here, each Asynchronous packet 503 stores an address (destination offset address) for specifying a predetermined area of the reception buffer 504 provided in the destination 403. For example, the first Asynchronous packet 5 of a certain segment
03 stores the start address of the reception buffer 504 notified by the controller 401. Also,
Subsequent Asynchronous packets store an offset address that sequentially specifies a predetermined area of the reception buffer 504.

If a bus reset 707 occurs during the transfer of a segment 502, the source 402 suspends the transfer of the segment. Destination 4
03 suspends the reception of the segment and the last Asynch normally received before the bus reset occurs.
The offset address contained in the ronous packet is stored in the above-mentioned internal register. In addition, the destination 403 does not discard the data stored in the reception buffer 504 (that is, the segment transferred halfway), and holds the data as it is.

Upon detecting the bus reset 707, the controller 401 terminates the bus reset processing, and
And whether the node ID of the destination 403 has changed. Thereafter, the controller 401 instructs the source 402 and the destination 403 to restart data transfer (708, 709).

Here, the command for instructing the source 402 to resume the transfer transferred includes a bus reset 70
7 stores the node ID of the destination 403 reset. This command is shown in FIG.
And the area 8 in the field 807
“1” is stored in 08 (retransmission identification bit). The source 402 recognizes the execution of the retransmission processing by reading the area 808.

Similarly, in the command for instructing the destination 403 to resume the transfer, the node ID of the source 402 set by the bus reset 707 is stored.

Upon receiving the instruction from the controller 401, the destination 403 notifies the source 402 of the offset address stored in the internal register and waits for a segment retransmitted from the source 402 (710).

Further, the source 402 receiving the instruction from the controller 401 waits for the notification of the offset address from the destination 403. After the notification of the offset address, the source 402 restarts the asynchronous transfer from the middle of the segment (711).

Here, the source 402 compares the value of the start address of the reception buffer 504 of the destination 403 stored in the above-mentioned internal register with the value of the offset address notified from the destination 403, By taking the difference, the data to start the transfer is identified.

For example, as shown in FIG. 9, when the lower 16 bits of the start address of the reception buffer 504 stored in the internal register are “0E00h” and the lower 16 bits of the above-mentioned offset address are “0E04h”, 402
Restarts the asynchronous transfer from the data 901 at the 5th byte in the segment whose transfer was interrupted by the bus reset.

After completion of the asynchronous transfer of this segment, the source 402 notifies the controller 4 of the completion of the transfer.
01 (712). Similarly, the destination 403 reports to the controller 401 that the reception of one segment has been completed (713).

As described above, even if a bus reset occurs during the transfer of one segment of data, 708 to 713 in FIG.
By executing the procedure shown in (1), the transfer of the segment can be restarted without restarting from the beginning.
When starting the transfer of the next and subsequent segments, the controller 401, the source 402, and the destination 4
03 may repeat the steps 704 to 713 again.

As described above, in the first embodiment, after the controller 401 detects a bus reset, it requests the source 402 and the destination 403 to resume transmission. The source 402 uses the offset address notified from the destination 403 that has received the request, selects data to be transmitted from the segment where the transfer was interrupted, and sequentially transfers the data to the asynchronous segment. I have.

Thus, even if a bus reset occurs during the transfer of each segment, it is possible to reduce the time required for resuming the transfer and the amount of data transferred redundantly, and to avoid a decrease in transmission efficiency. be able to.

(Second Embodiment) Hereinafter, the communication protocol of the second embodiment will be described in the same manner as the first embodiment.
A case where the present invention is applied to the communication system shown in FIG. 1 will be described. Here, the controller 4 in the second embodiment
01 is the TV 101, the source 402 is the DVCR 104, and the destination 403 is the printer 103.

Hereinafter, in the second embodiment, members or functions that are the same as or correspond to those in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 4, the communication protocol of the second embodiment is composed of three phases, ie, a connection phase 404, a transmission phase 405, and a connection release phase 406, as in the first embodiment. I have. Hereinafter, in the second embodiment, similarly to the first embodiment, the transmission phase will be described in detail.

FIG. 10 is a sequence chart for explaining in detail the transmission phase according to the second embodiment.
In FIG. 10, a procedure until a bus reset 707 occurs, that is, a procedure from 704 to 706 in FIG. 7 operates in the same manner as in the first embodiment, and a description thereof will be omitted. Hereinafter, processing after the occurrence of the bus reset 707 will be described.

When the bus reset 707 occurs during the asynchronous transfer of a certain segment, the source 702 suspends the transfer of the segment. While interrupting the transfer, the source 702 stores the offset address included in the last asynchronous packet 503 transmitted before the bus reset occurs in the internal register.

Here, the internal register in which the offset address is stored is the digital interface 105 provided in each device or the control unit 106 which controls the operation of each device.
Included in. Note that the above-described offset address is stored in an internal register different from the internal register in which the head address of the reception buffer 504 is stored.

The destination 403 interrupts the reception of the segment and sets the reception buffer 50
4 (that is, a segment that has been transferred halfway) is not discarded and is retained as it is.

After detecting the bus reset 707, the controller 401 sets the source 402
And whether the node ID of the destination 403 has changed. Thereafter, the controller 401 instructs the source 402 and the destination 403 to restart data transfer (1001, 1002).

Here, in the transfer restart command transferred to the source 402, the node ID of the destination 403 reset by the bus reset 707 is stored. This command is configured as shown in FIG. 2, and “1” is stored in an area 808 (retransmission identification bit) in the field 807. Source 40
2 recognizes the execution of the retransmission processing by reading the area 808.

Similarly, in the command for instructing the destination 403 to resume the transfer, the node ID of the source 402 set by the bus reset 707 is stored.

The destination 403 receiving the instruction from the controller 401 waits for data to be retransmitted from the source 402. Further, the source 402 receiving the instruction from the controller 401 reads the offset address stored in the above-described internal register, and resumes the asynchronous transfer from the data corresponding to the address (1003).

Here, the source 402 compares the value of the start address of the reception buffer 504 of the destination 403 stored in the above-mentioned internal register with the value of the above-mentioned offset address, and takes the difference. Identifies a part of the segment from which transfer is to be started.

For example, as shown in FIG. 9, when the lower 16 bits of the start address of the reception buffer 504 stored in the internal register are "0E00h" and the lower 16 bits of the offset address are "0E04h", the source 402
Restarts the asynchronous transfer from the data 901 at the 5th byte in the segment whose transfer was interrupted by the bus reset.

After the completion of the asynchronous transfer of this segment, the source 402 notifies the controller 4 of the completion of the transfer.
01 (712). Similarly, the destination 403 reports to the controller 401 that the reception of one segment has been completed (713).

As described above, even if a bus reset occurs during the transfer of data for one segment, by executing the procedure shown in FIG. 10, it is possible to restart all transfer of the segment without restarting from the beginning. it can.

To start the transfer of the next and subsequent segments, the controller 401, the source 402, and the destination 403 may repeat the procedure shown in FIG. 10 again.

As described above, in the second embodiment, after the controller 401 detects a bus reset, it requests the source 402 and the destination 403 to resume transmission. Then, the source 402 uses the offset address included in the asynchronous packet 503 normally transferred before the bus reset, selects data to be transmitted from the interrupted segment data, and sequentially transfers the data asynchronously. It is configured as follows.

Thus, even if a bus reset occurs during the transfer of each segment, it is possible to reduce the time required for resuming the transfer and the amount of data transferred redundantly, as in the first embodiment. It is possible to avoid a decrease in transmission efficiency.

(Third Embodiment) Hereinafter, a case where the communication protocol of the third embodiment is applied to the communication system shown in FIG. 1 will be described. Here, in the third embodiment, the controller 401 is the TV 101, the source 402 is the DVCR 104, and the destination 403.
Is a printer 103.

In the following, in the third embodiment, members or functions that are the same as or correspond to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the third embodiment, the source 402 divides the object data 501 into one or more segments 502, and transfers each segment 502 as one or more asynchronous packets 503 in an asynchronous manner.

The destination 403 includes one or more Asynchronous transferred from the source 402.
The synchronous packet 503 is received and stored in the internal memory for each segment. Further, the controller 401 queries the buffer size of the destination 403, selects object data transferred from the source 402,
It manages communication between the source 402 and the destination 403, such as specifying the size of a segment generated by the source 402.

Further, the communication protocol of the third embodiment has three phases, that is, the same as the first embodiment, that is, three phases:
It comprises a connection phase 404, a transmission phase 405, and a connection release phase 406. Hereinafter, in the third embodiment, the transmission phase will be described in detail.

FIG. 11 is a sequence chart for explaining in detail the transmission phase of the third embodiment.
In FIG. 11, the procedure up to the occurrence of the bus reset 707, that is, the procedure from 104 to 106 in FIG. 11 operates in the same manner as in the first embodiment, and a description thereof will be omitted. Hereinafter, processing after the occurrence of the bus reset 707 will be described.

When the bus reset 707 occurs during the asynchronous transfer of a certain segment, the source 402 suspends the transfer of the segment. Along with suspending the transfer, the source 402 stores the offset address included in the last asynchronous packet 503 normally transmitted before the bus reset occurs in the internal register.

Here, the internal register in which the offset address is stored is the digital interface 105 provided in each device or the control unit 106 which controls the operation of each device.
Included in. Note that the above-described offset address is stored in an internal register different from the internal register in which the head address of the reception buffer 504 is stored.

The destination 403 interrupts the reception of the segment, and retains the data stored in the reception buffer 504, that is, the segment transferred halfway, without discarding it.

After detecting the bus reset 707, the controller 401 sets the source 402
And whether the node ID of the destination 403 has changed. After that, the controller 401 sends to the source 402 the last successfully transmitted Asynchrono
A query is made for an offset address included in the us packet 503 (1101).

Here, the data part of the inquiry command transferred to the source 402 is configured as shown in FIG. 8, and the area 808 in the field 807 of the command is provided.
“1” is stored in (retransmission identification bit). The source 402 recognizes the execution of the retransmission processing by reading the area 808.

In response to this inquiry, the source 402 reads the offset address stored in the above-described internal register and notifies the controller 401 (110)
2). Controller 4 receiving notification from source 402
01 notifies the node ID of the destination 403 and instructs to restart the asynchronous transfer from the data corresponding to the offset address (1).
103).

The source 402 receiving the transfer restart instruction from the controller 401 restarts the asynchronous transfer from the data corresponding to the above-mentioned offset address (1).
104).

Here, the source 402 compares the value of the start address of the reception buffer 504 of the destination 403 with the value of the above-mentioned offset address, and obtains the difference to determine the segment to be transferred. Some are identified.

For example, as shown in FIG. 9, when the lower 16 bits of the start address of the reception buffer 504 stored in the internal register are “0E00h” and the lower 16 bits of the above-mentioned offset address are “0E04h”, the source 402
Restarts the asynchronous transfer from the data 901 at the 5th byte in the segment whose transfer was interrupted by the bus reset.

After the one-segment asynchronous transfer is completed, the source notifies the controller 401 of the completion of the transfer.
(712). Also, destination 4
03 also reports to the controller 401 that the reception of one segment has been completed (713).

As described above, even if a bus reset occurs during the transfer of one segment of data, by executing the procedure shown in FIG. 11, it is possible to restart all the transfer of the segment without restarting from the beginning. it can.

To start the transfer of the next and subsequent segments, the controller 401, the source 402, and the destination 403 may repeat the procedure shown in FIG. 11 again.

As described above, in the third embodiment, after the controller 401 detects a bus reset, the asynchronous packet 5 normally transferred before the bus reset is executed.
The source 402 is queried for an offset address included in the source address 03. Then, the controller 401 determines that the source 4
Source 402 so as to restart the asynchronous transfer from the data corresponding to the offset address notified from
It is configured to instruct.

Thus, even if a bus reset occurs during the transfer of each segment, it is possible to reduce the time required for resuming the transfer and the amount of data transferred in an overlapping manner, as in the first embodiment. It is possible to avoid a decrease in transmission efficiency.

(Other Embodiments) The above-described first to third embodiments can be realized as follows.
For example, a recording medium on which software program codes for realizing the functions of the above-described embodiments are recorded is supplied to a controller (including a microcomputer) provided in the controller 401, the source 402, and the destination 403 of the present embodiment. It can also be configured to do so.

Then, the controller 40 of the present embodiment
1, a control unit provided in the source 402 and the destination 403 reads the program code stored in the recording medium and controls the operation of the system or the apparatus so as to realize the functions of the above-described embodiment. Even so, the embodiment of the present invention can be realized.

For example, a recording medium storing program codes for realizing the processes and functions shown in FIG. 7 of the first embodiment, FIG. 10 of the second embodiment, and FIG. 11 of the third embodiment. Is supplied to the controller 401 of the controller 401, the source 402, and the destination 403.

Then, the controller 401 and the source 40
2. The control unit 106 of the destination 403 reads out the program code stored in the recording medium,
Each processing circuit provided in the controller 401, the source 402, and the destination 403 shown in FIG. 1 may be operated so as to realize the functions of the embodiments.

In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium storing the program code is a component of the present invention. Become.

As a recording medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

Also, an OS (Operating System) or application software running on the control unit controls the operation of the system or the apparatus according to the present embodiment based on the instruction of the program code read from the recording medium. Accordingly, it is needless to say that a case where the functions of the above-described embodiments are realized is also included in the present invention.

Further, after the program code read from the recording medium is written to the memory provided in the function expansion board or the function expansion unit connected to the control unit,
Based on the instructions of the program code, the control unit of the function expansion board or the function expansion unit controls the operation of the system or the device of the present embodiment,
It goes without saying that a case where the functions of the above-described embodiments are realized is also included in the present invention. It should be noted that the present invention can be implemented in various forms without departing from the spirit or main features thereof.

For example, in the first to third embodiments, a case has been described where the functions of the controller 401, the source 402, and the destination 403 are provided in different devices, but the present invention is not limited to this. For example, the controller 40 shown in the first to third embodiments
One function and the function of the source 402 may be provided in the same device.

With this configuration, the controller 4
01 and the source 402 are performed without passing through a transmission path common to each device, so that the transmission efficiency of the entire communication system can be further improved.

However, the present invention is more effective than the case where the controller 401 and the source 402 exist in the same device.
As shown in the first to third embodiments, the controller 4
01, the source 402, and the destination 403 exist as separate devices, respectively, so that a higher effect can be achieved. This means that the controller 40
The same applies to the case where the function 1 and the function of the destination 403 exist in the same device. Therefore, the above-described embodiment is merely an example in every aspect, and should not be interpreted in a limited manner.

[0133]

As described above, according to the present invention, when one object is divided into a plurality of segments and transferred, even if a bus reset occurs during the transfer of information data for a certain segment, the problem is solved. The transfer can be resumed without restarting the transfer of the segment from the beginning. In addition, it is possible to reduce the time required for resuming the transfer and the amount of data transferred in an overlapping manner, and to avoid deterioration in transmission efficiency.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a configuration of a 1394 interface according to the present embodiment.

FIG. 3 is a diagram illustrating a transfer method of a 1394 interface.

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

FIG. 5 is a diagram illustrating a transfer model of object data.

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

FIG. 7 is a diagram illustrating a communication protocol according to the first embodiment.

FIG. 8 is a diagram showing a configuration of a communication packet transferred from a controller to a source.

FIG. 9 is a diagram illustrating an internal address included in a source.

FIG. 10 is a sequence chart illustrating a communication protocol according to the second embodiment.

FIG. 11 is a sequence chart illustrating a communication protocol according to the third embodiment.

[Explanation of symbols]

 Reference Signs List 101 TV 102 DVTR 103 Printer 104 DVCR 105 Digital interface 106 Control unit 107 Signal processing unit 401 Controller 402 Source 403 Destination

Claims (65)

[Claims] 1. A data communication system comprising: a source for transmitting information data; a destination for receiving the information data; and a controller for managing communication between the source and the destination. The data communication system, characterized in that the transmission of the information data, which has been suspended due to the above, is restarted from a part of the information data based on negotiation between the source and the destination. 2. The data communication according to claim 1, wherein the source divides the information data into one or more segment data, and transmits the segment data in one or more data units. system. 3. The apparatus according to claim 1, wherein the source packetizes the information data into one or more communication packets, and transmits the one or more communication packets asynchronously.
Or the data communication system according to 2. 4. The data communication system according to claim 1, wherein the source holds a head address of a memory space included in the destination. 5. The information processing apparatus according to claim 1, wherein the source identifies a part of the information data to be transmitted by using an address of a memory in which the information data transmitted before the bus reset is stored. The data communication system according to any one of claims 1 to 4. 6. The source according to claim 1, wherein the destination notifies the source of an address of a memory in which information data received before the bus reset is stored. Data communication system. 7. The data communication system according to claim 6, wherein the source identifies a part of the information data to be transmitted by using an address notified from the destination. 8. The destination according to claim 1, wherein even if the bus reset occurs, the destination does not discard information data received before the bus reset.
The data communication system according to claim 1. 9. The data communication system according to claim 1, wherein the bus reset occurs according to a change in a connection configuration of the data communication system. 10. The bus reset is a process for automatically re-recognizing a connection configuration of the data communication system and setting a communication address of a device constituting the data communication system. The data communication system according to any one of claims 1 to 9. 11. The data communication according to claim 1, wherein the function of the source and the function of the controller may be included in the same device. system. 12. The data according to claim 1, wherein the function provided in the destination and the function provided in the controller may be provided in the same device. Communications system. 13. A transmission means for transmitting information data to a destination, a storage means for storing first information for specifying a predetermined area of a memory provided in the destination, and the destination in response to a bus reset. A data communication apparatus, comprising: selecting means for selecting a part of information data to be transmitted using the second information notified from the first information and the first information. 14. A receiving means for receiving information data transmitted from a source, and a notifying means for notifying the source of an address specifying a memory space in which a part of the information data is stored after initial setting of a network. A data communication device comprising: 15. The data communication device according to claim 14, wherein the data communication device does not discard a part of the information data stored in the memory even when the bus reset occurs. 16. A transmitting means for transmitting information data to a destination, a storing means for storing first information for specifying a predetermined area of a memory provided in the destination; Selecting means for selecting a part of information data to be transmitted by using second information specifying a memory in which a part of the interrupted information data is stored and the first information; A data communication device characterized by the above-mentioned. 17. A receiving unit for receiving information data transmitted from a source, and a part of the information data transmitted from the source without discarding the information data whose reception has been interrupted after network initialization. And a control means for controlling to wait for the data communication. 18. A data communication applicable to a data communication system including a source for transmitting information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. The method according to claim 1, wherein the transmission of the information data interrupted by the initialization of a network is restarted from a part of the information data based on negotiation between the source and the destination. 19. A data communication method applicable to a data communication apparatus for transmitting information data to a destination, comprising: first information for specifying a predetermined area of a memory provided in the destination; A data communication method, wherein a part of information data to be transmitted is selected using the second information notified from the destination after the setting. 20. A data communication method applicable to a data communication device for receiving information data transmitted from a source, wherein after a network is initialized, a memory space in which a part of the information data is stored is designated. A data communication method comprising: notifying an address to the source. 21. A data communication method applicable to a data communication device for transmitting information data to a destination, comprising: first information for specifying a predetermined area of a memory space provided in the destination; Selecting a part of the information data to be transmitted by using, after the initial setting, second information designating a memory space in which a part of the information data whose transmission has been interrupted is stored; Communication method. 22. A data communication method applicable to a data communication apparatus for receiving information data transmitted from a source, comprising: after initializing a network, discarding the information data whose reception has been interrupted without discarding the information data. A data communication method comprising: controlling to wait for a part of the information data transmitted from the server. 23. A data communication system comprising: a source for transmitting information data; a destination for receiving the information data; and a controller for managing communication between the source and the destination. A program for realizing a function of restarting transmission of the information data interrupted due to negotiation between the source and the destination from a part of the information data is stored in a computer-readable manner. A storage medium characterized by the above-mentioned. 24. A data communication system comprising: a source for transmitting information data; a destination for receiving the information data; and a controller for managing communication between the source and the destination. Transmitting the information data, which has been interrupted due to the above, from a part of the information data based on negotiation between the controller and the source. 25. In a data communication apparatus in which communication with a destination is managed by a controller, a notifying means for notifying the controller of an address designating a memory space for storing data to be interrupted after initial setting of a network. A data communication device comprising: a transmission unit that restarts transmission from data corresponding to the address in response to an instruction from the controller. 26. A data communication method applicable to a data communication device in which communication with a destination is managed by a controller, wherein after an initial setting of a network, an address designating a memory space for storing data to resume transmission is set. A data communication method comprising: notifying a controller, and restarting transmission from data corresponding to the address in response to an instruction from the controller. 27. Data communication adaptable to a data communication system including a source for transmitting information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. The method of claim 1, wherein the transmission of the data interrupted due to network initialization is restarted from a part of the information data based on negotiation between the source and the controller. 28. A data communication device in which communication with a destination is managed by a controller, after initializing a network, notifying the controller of an address designating a memory space for storing data to resume transmission, A program for realizing a function of restarting transmission from data corresponding to the address in response to an instruction from the computer, the program being stored in a computer-readable manner. 29. A data communication system comprising: a source for transmitting information data; a destination for receiving the information data; and a controller for managing communication between the source and the destination. Based on negotiations between the source and the controller, the transmission of the information data interrupted by the controller is restarted from a part of the information data, and a program for realizing the function is stored in a computer-readable manner. Characteristic storage medium. 30. A data communication system comprising: a source for transmitting information data; a destination for receiving the information data; and a controller for managing communication between the source and the destination. A data communication system characterized in that information data whose transmission has been interrupted due to the above is specified between the source and the destination, and transmission is restarted from the specified information data. 31. A data communication applicable to a data communication system including a source for transmitting information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. A data communication method comprising: identifying information data, the transmission of which has been interrupted due to network initialization, between the source and the destination, and resuming the transfer from the identified information data. Method. 32. A transmitting means for transmitting information data to a destination, and information information whose transmission has been interrupted by a bus reset,
A data communication device comprising: a control unit that specifies between the destination and the destination, and controls to restart the transfer from the specified information data. 33. A data communication system comprising: a source for transmitting information data, a destination for receiving the information data, and a controller for managing communication between the source and the destination. A program for realizing a function of specifying the information data whose transmission has been interrupted due to the above and between the source and the destination and restarting the transfer from the specified information data is stored in a computer-readable manner. A storage medium characterized by the following. 34. A source for transferring information data by using an address specifying a part of a memory space of a destination, and a destination for storing the information data in a part of a memory space specified by the address. And a controller that manages data transfer between the source and the destination, using an address managed by the source when the transfer of the information data is interrupted due to network initialization. A data communication system for restarting transfer from a part of the information data. 35. The data communication system according to claim 34, wherein said information data is transferred by one or more packets for every one or more segments. 36. The data communication system according to claim 34, wherein said packets are transferred continuously. 37. The data communication system according to claim 34, wherein said address is stored in said packet. 38. The data communication system according to claim 34, wherein the address is different for each packet. 39. The data communication system according to claim 34, wherein the transfer of the information data is started using an address specified by the controller. 40. The data communication system according to claim 34, wherein said initial setting is performed when a connection configuration of said network changes. 41. The data communication system according to claim 34, wherein said initial setting includes a process of automatically recognizing a connection configuration of said network. 42. The information data is based on IEEE1394
42. The data communication system according to any one of claims 34 to 41, wherein the data is transferred using an Asynchronous transfer method of -1995 standard. 43. The network as defined in IEEE 139.
43. The data communication system according to claim 34, wherein the data communication system is a network compliant with the 4-1995 standard. 44. The data communication system according to claim 34, wherein said information data is at least one of image data, graphics data, and text data. 45. A source for transferring information data by using an address specifying a part of a memory space of a destination, and a destination for storing the information data in a part of a memory space specified by the address. And a controller for managing data transfer between the source and the destination, and when the transfer of the information data is interrupted due to the initial setting of a network, an address specified by the destination. A data communication system characterized by restarting the transfer from a part of the information data by using the data communication. 46. A step of transferring information data using an address designating a part of a memory space of a destination; and a step of storing the information data in a part of a memory space designated by the address. When the transfer of the information data is interrupted due to the initial setting of the network, the step of restarting the transfer from a part of the information data using an address managed by the source. Communication method. 47. A step of transferring information data by using an address designating a part of a memory space of a destination, comprising the steps of: Restarting transfer from a part of the information data using an address managed by the source. 48. The information data transferred from the source,
Storing in a part of a memory space designated by the source; and notifying an address necessary for resuming the transfer of the information data when the transfer of the information data is interrupted due to initialization of a network. Restarting the transfer from part of the information data without performing the data communication method. 49. A step of notifying a source of an address designating a part of a memory space of a destination, and instructing a start of transfer of information data; and And controlling the transfer so as to restart the transfer from a part of the information data without notifying the address necessary for restarting the transfer of the information data when the transfer of the information data is interrupted. Data communication method. 50. A step of transferring information data using an address designating a part of a memory space of a destination; and a step of storing the information data in a part of a memory space designated by the address. When the transfer of the information data is interrupted due to the initial setting of the network, a step of restarting the transfer from a part of the information data by using the address specified by the destination. Data communication method. 51. A step of transferring information data by using an address designating a part of a memory space of a destination, wherein the transfer of the information data is interrupted by the initial setting of a network. Restarting the transfer from a part of the information data by using the address specified by the destination. 52. The information data transferred from the source,
Storing in a part of a memory space designated by the source; and designating a part of the memory space to the source when the transfer of the information data is interrupted due to network initialization. Notifying an address to be performed. 53. A step of instructing a source to specify an address for designating a part of a memory space of a destination, and instructing a start of transfer of information data; and Instructing the source to notify an address designating a part of the memory space when the transfer of the data is interrupted. 54. A means for transferring information data by using an address designating a part of a memory space of a destination, comprising: Means for controlling so as to restart transfer from a part of the information data by using the managed address. 55. The information data transferred from the source,
Means for storing the information data in a part of a memory space designated by the source; and notifying an address necessary for resuming the transfer of the information data when the transfer of the information data is interrupted due to network initialization. Means for controlling the transfer of a part of the information data without resuming the transfer. 56. A means for transferring information data by using an address designating a part of a memory space of a destination, comprising: Means for controlling to restart transfer from a part of the information data using an address designated by the destination. 57. The information data transferred from the source,
Means for storing in a part of a memory space designated by the source; and designation of a part of the memory space to the source when transfer of the information data is interrupted due to network initialization. And a means for notifying an address to be transmitted. 58. A means for notifying a source of an address designating a part of a memory space of a destination, and instructing a start of transfer of information data; and Means for controlling so as to restart the transfer of the information data without discarding a part of the data stored in the memory space when the transfer of the information is interrupted. apparatus. 59. A means for instructing a source to specify an address for designating a part of a memory space of a destination, and for instructing a start of transfer of information data; Means for instructing the source at an address specifying a part of the memory space when the transfer of the data is interrupted. 60. A step of transferring information data by using an address designating a part of a memory space of a destination, comprising the steps of: Restarting transfer from a part of the information data using an address managed by the source. 61. The information data transferred from the source,
Storing in a part of a memory space designated by the source; and notifying an address necessary for resuming the transfer of the information data when the transfer of the information data is interrupted due to initialization of a network. And a step of restarting transfer from a part of the information data without performing the data communication method. 62. A step of informing a source of an address designating a part of a memory space of a destination, and instructing a start of transfer of information data, wherein the information data is transmitted along with a network initialization. And controlling, when the transfer of the information data is interrupted, to restart the transfer from a part of the information data without notifying an address necessary for resuming the transfer of the information data. Possible digital interface. 63. A means for transferring information data by using an address designating a part of a memory space of a destination, comprising: Means for restarting transfer from a part of the information data using an address designated by the destination. 64. The information data transferred from the source,
Means for storing in a part of a memory space designated by the source; and designation of a part of the memory space to the source when transfer of the information data is interrupted due to network initialization. Means for notifying an address to be performed. 65. A means for instructing a source to specify an address for designating a part of a memory space of a destination, and for instructing a start of transfer of information data; Means for instructing the source to notify the source of an address designating a part of the memory space when the transfer of the data is interrupted.