JP2006311614A - Data communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform data communication between apparatuses by connecting a plurality of electronic apparatuses by using a data communication bus capable of performing communication by making a control signal and data coexist. <P>SOLUTION: The communication of the information data is performed by using first ID information indicating a virtual communication relation composed of N-pieces of apparatuses included in a plurality of apparatuses and second ID information for discriminating information data communicated among the N-pieces apparatuses. Thus, the inconvenience of a conventional communication system is eliminated, and multicast transfer can simply be achieved at high speed even in the data transfer without the need of real time performance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a data communication system, a data communication apparatus, a data communication method, and a storage medium, and in particular, a plurality of electronic devices (hereinafter referred to as devices) using a data communication bus capable of communicating by mixing control signals and data. The present invention relates to a data communication system that connects devices and performs data communication between devices, and an apparatus and method that configure the data communication system.

  Among personal computer peripherals, hard disks and printers are most frequently used. These peripheral devices are general-purpose interfaces for small computers, such as SCSI, which is a typical digital interface (hereinafter referred to as digital I / F). In this way, connections between personal computers are made and data communication is performed.

  In addition, recording and playback devices such as digital cameras and digital video cameras are one of the peripheral devices as input means to a personal computer (hereinafter referred to as “PC”). In recent years, images such as still images and videos taken with digital cameras and video cameras have been recorded. The technology in the field of importing to a PC, storing it on a hard disk, or editing with a PC and then printing with a printer is advancing, and the number of users is increasing.

  When the captured image data is output from a PC to a printer or hard disk, data communication is performed via the SCSI or the like. In such a case, information with a large amount of data such as image data is used. In order to send data, these digital I / Fs must have a high transfer data rate and versatility.

  FIG. 8 shows a block diagram when a digital camera, a PC, and a printer are connected as a conventional example. In FIG. 8, 101 is a digital camera, 102 is a personal computer (PC), and 103 is a printer. Further, 104 is a memory that is a recording unit of the digital camera, 105 is an image data decoding circuit, 106 is an image processing unit, 107 is a D / A converter, 108 is an EVF that is a display unit, and 109 is a digital I / O of the digital camera. An O unit, 110 is a digital I / O unit with a PC digital camera, 111 is an operation unit such as a keyboard or a mouse, and 112 is an image data decoding circuit.

  113 is a display, 114 is a hard disk drive, 115 is a memory such as RAM, 116 is an MPU of an arithmetic processing unit, 117 is a PCI bus, 118 is a digital interface SCSI interface (board), 119 is connected to a PC via a SCSI cable The printer SCSI interface, 120 is a memory, 121 is a printer head, 122 is a printer controller of the printer control unit, and 123 is a driver.

  This section describes the procedure for importing images taken with a digital camera into a PC and outputting them from a PC to a printer. When the image data stored in the memory 104 of the digital camera 101 is read, one of the read image data is decoded by the decoding circuit 105 and image processing for display by the image processing circuit 106 is performed. Is displayed on the EVF 108 via the D / A converter 107. On the other hand, from the digital I / O unit 109 for external output, the digital I / O unit 110 of the PC 102 reaches the digital I / O unit 110 via the cable.

  In the PC 102, the image data input from the digital I / O unit 110 is stored in the hard disk 114 when stored using the PCI bus 117 as a mutual transmission bus, and is decoded by the decoding circuit 112 when displayed. Thereafter, the image is stored in the memory 115 as a display image, converted into an analog signal by the display 113, and then displayed. Operation input such as editing on the PC 102 is performed from the operation unit 111, and processing of the entire PC 102 is performed by the MPU 116.

  When printing an image, the image data is transmitted from the SCSI interface board 118 in the PC 102 on the SCSI cable, received by the SCS I interface 119 on the printer 103 side, and formed as a print image in the memory 120. The printer head 121 and the driver 123 operate under the control of the printer controller 122 and print image data read from the memory 120 is printed. The above is the procedure until the conventional image data is taken into the PC or printed.

  As described above, conventionally, each device is connected to a host PC, and image data captured by the recording / reproducing apparatus is printed through the PC. In addition, AV devices such as digital VTRs, TVs and tuners, personal computers (hereinafter referred to as PCs), etc. are connected to each other using an IEEE 1394 serial bus (hereinafter referred to as 1394), and digital devices are connected between them. Communication systems that transmit and receive video signals, digital audio signals, and the like have been proposed.

  In these systems, since it is important to transfer data in real time, data communication is performed by so-called synchronous communication (hereinafter referred to as isochronous communication). In this case, the real-time property of data transfer is guaranteed, but it is not guaranteed whether communication is performed reliably.

  However, the problems with the digital interface mentioned in the above-mentioned conventional example are that the transfer data rate of SCSI is low, the cable is thick for parallel communication, the types and number of connected peripheral devices, the connection method, etc. There are limitations and many inconveniences have been pointed out.

  Further, in the case of conventional IEEE 1394 communication, since synchronous communication is performed, it is not guaranteed that the communication is reliably performed. Therefore, when it is desired to transfer data reliably, conventional 1394 isochronous communication cannot be used.

  Further, in the conventional 1394 isochronous communication, the total number of communication is limited to 64 even when there is a free communication band. For this reason, there has been a problem that conventional 1394 isochronous communication cannot be used when it is desired to perform many communications that do not require much communication bandwidth. Further, in the conventional 1394 communication system, it is conceivable that the data transfer is interrupted due to a bus reset or an error during the data transfer.

  In this case, the conventional 1394 communication method cannot know what data content has been lost. Therefore, the conventional 1394 communication system has a problem that it is required to take a very complicated communication procedure in order to recover from the interruption of the data transfer.

The present invention has been made in order to solve the above-mentioned problems. It is an object of the present invention to solve the inconvenience of the conventional communication method, to easily transfer data at high speed and to enable reliable data transfer. 1 purpose.
In addition, a second object of the present invention is to enable a large number of communications simultaneously when a communication band is not used much.
A third object of the present invention is to make it possible to easily detect data lost due to data transfer interruption and to reliably and easily recover from the data transfer interruption. .
Further, in the present invention, when there are a plurality of control nodes on the network, there is no means for identifying the logical connection set by each control node. A fourth object is to provide means for transmitting data from one source node to a plurality of destination nodes.
A fifth object of the present invention is to prevent a multicast packet from being received by a conventional 1394 standard device in realizing multicast transfer.

  In order to solve the conventional problems, the present invention eliminates the problems of conventional digital I / F as much as possible, and is a general-purpose digital I / F (for example, IEEE1394) that is integrated and installed in each digital device. -1995 High-Performance Serial Bus) enables inter-device data communication when a PC, printer, other peripheral device, digital camera, digital VTR recording / playback device, etc. are connected in a network configuration. Import video data to a PC and transfer video data directly to a printer for printing. In such a network, a protocol is provided for transmitting various data by dividing each data into a plurality of data by an asynchronous transaction.

  An ID, which is unique node information possessed by the control node and does not change due to a bus reset or the like, is added to the payload. The control node announces the number of destinations logically connected to the source.

  The source node waits for a reception acknowledgment packet from the destination for each buffer size from the destination, and transmits the next segment packet. In response to a packet indicating the end of transmission data from the source node, each destination returns a reception confirmation response packet.

  A destination Destination Bus ID bus address from the source node in multicast transmission is set not to be 3 FF (h) which is a local bus, but an address of 0 to 3 FE or less is set.

The data communication system according to the present invention is a data communication system configured by a plurality of devices, and includes first information indicating a virtual communication relationship configured by N devices included in the plurality of devices, and the N The information data is communicated using second information for determining information data communicated between individual devices. Here, the first information corresponds to the multicast ID described in the embodiment. The second information corresponds to the connection ID described in the present embodiment.
Another feature of the data communication system of the present invention is that the data communication system includes a management device having a function of managing the first and second information, and the management device is used to It is characterized by controlling communication between N devices.
Another feature of the data communication system according to the present invention is that the management device transmits the first information and the second information to each of the N devices.
According to another feature of the data communication system of the present invention, the management device transmits unique ID information unique to the management device together with the first and second information to each of the N devices. It is characterized by transmitting.
According to still another feature of the data communication system of the present invention, the N devices identify the management device in which the first and second information are set using the unique ID information. It is said.
Another feature of the data communication system according to the present invention is that the management device communicates with each of the N devices using an asynchronous transfer method compliant with the IEEE 1394 standard. Yes.
Another feature of the data communication system according to the present invention is that the N devices manage additional information related to the first and second information using a table.
According to another feature of the data communication system of the present invention, the N devices transmit the information data using a communication packet constituted by the first and second information. It is said.
According to another feature of the data communication system of the present invention, the first information is stored in a header portion of the communication packet, and the second information is stored in a data portion of the communication packet. It is characterized by having.
Another feature of the data communication system of the present invention is that the information data is stored in a memory space corresponding to the second information.
Another feature of the data communication system according to the present invention is that the first information indicates a logical connection relationship constituted by one transmitting device and a plurality of receiving devices. .
Another feature of the data communication system of the present invention is that the second information is information for determining each of a plurality of different information data communicated between the N devices. It is said.
Another feature of the data communication system according to the present invention is that information data output from each of the N devices is transferred to all the devices constituting the data communication system. Yes.
Another feature of the data communication system according to the present invention is that information data output from each of the N devices is transferred using an Asynchronous transfer method compliant with the IEEE 1394 standard. Yes.
Another feature of the data communication system of the present invention is that the management device terminates communication of the information data by an end flag transmitted from the device that transmits the information data. .
Another feature of the data communication system of the present invention is that the virtual communication relationship is released by the management device or a device that receives the information data.
Another feature of the data communication system according to the present invention is that a device that receives the information data responds to a request that configures the virtual communication relationship with a size of a reception buffer and a predetermined amount in a memory space. A packet including at least one of address information indicating the area, a sequential number indicating a data start pointer, and information indicating completion of preparation is transmitted.
According to another feature of the data communication system of the present invention, the device that transmits the information data measures a response from the device that receives the information data for a predetermined period, and detects a communication abnormality in the period. It is characterized by that.
Another feature of the data communication system of the present invention is that a device that transmits the information data automatically starts a retransmission operation of the information data when the communication abnormality is detected. It is said.
Another feature of the data communication system of the present invention is that information indicating a virtual communication relationship constituted by N devices included in the plurality of devices and communication between the N devices. The information data is communicated using information designating a virtual memory space for storing the information data to be stored. Here, the information indicating the virtual communication relationship corresponds to the multicast ID described in the present embodiment. The information specifying the virtual memory space corresponds to the destination offset described in this embodiment.
Another feature of the data communication system of the present invention is that a virtual communication environment is set using a plurality of pieces of ID information. Here, the plurality of ID information includes any one of the multicast ID, the connection ID, and the destination offset described in the present embodiment.

The data communication apparatus according to the present invention is a data communication apparatus connectable to a data communication system configured by a plurality of devices, and indicates a virtual communication relationship configured by N devices included in the plurality of devices. Using setting means for setting information 1 and second information for determining information data communicated between the N devices, and using the first and second information set by the setting means And communication means for performing communication of the information data. Here, the first information corresponds to the multicast ID described in the embodiment. The second information corresponds to the connection ID described in the present embodiment.
Another feature of the data communication apparatus according to the present invention is that the data communication apparatus is connectable to a data communication system configured by a plurality of devices, and is configured by N devices included in the plurality of devices. Receiving means for receiving the information data including first information indicating a virtual communication relationship and second information for determining information data communicated between the N devices; and And determining means for determining whether or not the information data received by the receiving means is data transmitted to itself using the information of the second information.
In addition, the other feature of the data communication device of the present invention is a data communication device connectable to a data communication system constituted by a plurality of devices.
Information indicating a virtual communication relationship constituted by N devices included in the plurality of devices, information specifying a virtual memory space for storing information data communicated between the N devices, and And a communication means for communicating the information data using the first and second information set by the setting means. Here, the information indicating the virtual communication relationship corresponds to the multicast ID described in the present embodiment. The information specifying the virtual memory space corresponds to the destination offset described in this embodiment.
Another feature of the data communication apparatus according to the present invention is that the data communication apparatus is connectable to a data communication system including a plurality of devices, and is configured by N devices included in the plurality of devices. Receiving means for receiving information data including information indicating a virtual communication relationship and information designating a virtual memory space for storing information data communicated between the N devices; And determining means for determining whether or not the information data received by the receiving means is data transmitted to itself using the second information. Here, the information indicating the virtual communication relationship corresponds to the multicast ID described in the present embodiment. The information specifying the virtual memory space corresponds to the destination offset described in this embodiment.

The data communication method of the present invention is a data communication method applicable to a data communication system constituted by a plurality of devices, and shows a virtual communication relationship constituted by N devices included in the plurality of devices. The information data is communicated using the first information and the second information for determining the information data communicated between the N devices. Here, the first information corresponds to the multicast ID described in the embodiment. The second information corresponds to the connection ID described in the present embodiment.
According to another aspect of the data communication method of the present invention, the data communication method is applicable to a data communication system including a plurality of devices, and is configured by N devices included in the plurality of devices. The information data is communicated using a communication packet including information indicating a virtual communication relationship and information designating a virtual memory space for storing information data communicated between the N devices. It is characterized by that. Here, the information indicating the virtual communication relationship corresponds to the multicast ID described in the present embodiment. The information specifying the virtual memory space corresponds to the destination offset described in this embodiment.
Another feature of the data communication method of the present invention is that, in a data communication method applicable to a data communication system composed of a plurality of devices, a virtual communication environment is set using a plurality of ID information. It is characterized by doing.
According to another aspect of the data communication method of the present invention, the data communication method is applicable to a data communication system including a plurality of devices, and is configured by N devices included in the plurality of devices. The information data is data transmitted to itself using first information indicating a virtual communication relationship and second information for determining information data communicated between the N devices. It is characterized by determining whether or not. Here, the plurality of ID information includes any one of the multicast ID, the connection ID, and the destination offset described in the present embodiment.
According to another aspect of the data communication method of the present invention, the data communication method is applicable to a data communication system including a plurality of devices, and is configured by N devices included in the plurality of devices. The information data is transmitted to itself using information indicating a virtual communication relationship and information specifying a virtual memory space for storing information data communicated between the N devices. It is characterized by determining whether or not. Here, the information indicating the virtual communication relationship corresponds to the multicast ID described in the present embodiment. The information specifying the virtual memory space corresponds to the destination offset described in this embodiment.

The storage medium of the present invention is characterized in that a program for causing a computer to function as each of the means is stored. Here, the first information corresponds to the multicast ID described in the embodiment.
Another aspect of the storage medium of the present invention is a storage medium storing a program for causing a computer to execute the procedure of the data communication method.
Since the present invention has the above technical means, the controller node sets an independent connection ID uniquely determined in the network, establishes a logical connection between the source and destination nodes, and sets each logical connection. Assign the connection ID. Thereafter, in handshake communication between the source and destination nodes, communication is performed using a so-called broadcast asynchronous transaction in which the connection ID number set by the controller is included in a field in the payload.

  Each node determines the connection ID in the payload, determines whether or not the connection is set between its own nodes, and excludes all other than the set connection ID by itself.

  The source node transmits a broadcast packet having a connection request flag to the destination node, and the destination node receives buffer size information that can be received as soon as the node is ready to receive data, and the start of the data packet. The data sequence number indicating the order is included, the Ack bit is set, and communication is performed using a so-called broadcast asynchronous transaction.

  The source node receives the packet transmitted by broadcast, determines the connection ID, and confirms that it is an Ack response from the destination node. Thus, data transfer is started.

  In addition, the source and destination nodes identify logical connections individually set between the source and destination based on the unique ID of the control node in the payload and the connection ID set by the control node. .

  In addition, data is transmitted to a plurality of connected destinations using a single connection ID. Since the conventional 1394 device is not 3 FF (h) indicating that the destination bus ID is local, even if the destination physical ID is 3 F (h), a packet that has been easily transferred by multicast is not used. Can be deleted.

According to the present invention, it is possible to solve the inconvenience caused by the conventional communication method.
In addition, even in data transfer that does not require real-time properties, an effect that data can be transferred easily at high speed can be obtained.
In addition, according to the present invention, there is an effect that a large number of communications can be performed simultaneously when a communication band is not used much.
Further, according to the present invention, it is possible to easily detect data lost due to interruption of data transfer, and it is possible to reliably and easily return from interruption of the data transfer. Is obtained.
Further, according to the present invention, there is no need to adjust so that connection IDs do not overlap among a plurality of controls, so that the controller can easily and surely set an effect.
Further, according to the present invention, even when a plurality of control nodes individually set a plurality of logical connections between a source and a destination, each node is the node-specific information on the controller that sets the connection. Since it is possible to discriminate by a unique node ID such as a world wide unique ID, an effect is obtained in which each node can reliably identify a logical connection.
In addition, according to the present invention, data can be easily transmitted to a plurality of destinations with a single logical connection ID as a single segment packet, so that an effect of reducing traffic on the bus is obtained. It is done.
In addition, since there is no need to set a plurality of connection IDs, an effect of facilitating initial setting of the connection ID of the controller can be obtained.
Further, according to the present invention, even if the reception buffers of the respective destinations are different, the source only needs to manage and transmit only the reception buffer size of the respective destinations. The flow may be sufficient, and the effect of facilitating mounting can be obtained.
Further, according to the present invention, even when the same object is transferred from one source node to a plurality of N destinations, it is not necessary to send N segments to each destination. Since the transfer can be performed efficiently in the segment, the effect of not increasing the traffic on the 1394 bus can be obtained.
Further, according to the present invention, since a Bus ID other than the local bus is used for multicasting, unnecessary processing that a conventional 1394 standard device recognizes and receives as a local broadcast is eliminated. The effect that there is no influence on the equipment is obtained.
In addition, according to the present invention, since an individual multicast ID is used, a device conforming to the present invention has a multicast ID written in the destination ID of the Asynchronous Write packet as compared with the case of using a broadcast Asynchronous Write transaction. Since it is possible to determine whether or not to capture a packet by simply comparing the multicast ID notified from the controller, an effect of reducing the processing can be obtained.
In addition, according to the present invention, it is possible to set 63 or more logical connections by associating the destination offset address with the connection ID.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, 10 is a computer, 12 is an arithmetic processing unit (MPU), 14 is a first 1394 interface, 16 is a first operation unit such as a keyboard, 18 is a first decoder, 20 is a CRT display, etc. A display device, 22 is a hard disk, 24 is a first memory, the internal memory of the computer 10 according to the present invention, and 26 is a computer internal bus such as a PCI bus.

  28 is a VCR, 30 is an imaging optical system, 32 is an analog-digital (A / D) converter, 34 is a video processing unit, 36 is a compression / decompression circuit, 38 is a first memory, and 40 is a second memory. Memory, 42 is a first data selector, 44 is a second 1394 interface, 46 is a first memory control circuit, 48 is a second memory control circuit, 50 is a system controller, 52 is a second operation unit, 54 is a viewfinder, 56 is a D / A converter, and 58 is a recording unit.

  Further, 60 is a printer, 62 is a third 1394 interface, 64 is a second data selector, 66 is a third operation unit, 68 is a printer controller, 70 is a second decoder, and 72 is a third memory. 74 denotes an image processing unit, 76 denotes a driver, and 78 denotes a printer head.

  The computer 10, the VCR 28, and the printer 60 constitute a 1394 serial bus node by the first to third 1394 interfaces 14, 44, 62, and the first to third 1394 interfaces 14, 44, 62. Are connected to each other via a network, and data can be exchanged or controlled by commands.

  In the present embodiment, for example, the computer 10 operates as a controller for image signal transmission / reception on the 1394 serial bus. In the computer 10 according to the present embodiment, for example, by a computer internal bus 26 such as a PCI bus, 12 is an arithmetic processing unit (MPU), 1394 interface 14, keyboard 16, decoder 18, CRT display 20, hard disk 22, internal Internal devices such as the memory 24 are connected to each other.

  An arithmetic processing unit (MPU) 12 executes software recorded on the hard disk 22 and moves various data to the internal memory 24. Reference numeral 12 denotes an arithmetic processing unit (MPU) that performs arbitration operations of devices connected by the PCI bus 26 together. The 1394 interface 14 receives an image signal transferred on the 1394 serial bus, and transmits an image signal recorded on the hard disk 22 and an image signal stored in the internal memory 24.

  The 1394 interface 14 transmits command data to other devices connected on the 1394 serial bus. The 1394 interface 14 transfers a signal transferred on the 1394 serial bus to another 1394 node.

  The operator causes the MPU 12 to execute the software recorded on the hard disk 22 through the operation unit such as the keyboard 16. Information such as the software is presented to the operator by a display device 20 such as a CRT display.

  The decoder 18 decodes the image signal received from the 1394 serial bus through the software. The decoded image signal is also presented to the operator by a display device 20 such as a CRT display.

  In the present embodiment, for example, the VCR 28 operates as an image signal input device. The video luminance signal (Y) and color difference signal (C) input from the image pickup optical system 30 are converted into digital data by the A / D converter 32, respectively.

  The digital data is multiplexed by the video processing unit 34. Thereafter, the compression / decompression circuit 36 compresses the data amount of the image information. In general, the compression processing circuit is provided independently for YC, but here, for the sake of simplification of explanation, an example of compression processing in YC time division is shown.

  Next, shuffling is performed for the purpose of making the image data resistant to transmission path errors. The purpose of this process is to convert a burst error, which is a continuous code error, into a random error, which is a discrete error that can be easily corrected and interpolated. In addition, if importance is attached to the purpose of uniforming the bias in the generation of information amount due to density in the image screen, if this processing step is brought before the compression processing, a variable length code such as run length can be added. Convenient when used.

  In response to this, data identification (ID) information for restoring data shuffling is added. The ID added by the ID adding operation is used as auxiliary information in the reverse compression processing (information amount expansion processing) at the time of reproduction together with the mode information of the system recorded at the same time. In order to reduce errors during reproduction of these data, error correction (ECC) information is added. Up to the addition of such a redundant signal is processed for each independent recording area corresponding to information such as video and audio.

  As described above, the image signal to which ID information or ECC information is added is recorded on a recording medium such as a magnetic tape by the recording unit 58 and temporarily stored in a first memory 38 to be described later.

  On the other hand, the image data multiplexed in the video processing unit 34 is converted from digital to analog by the D / A converter 56 and observed by the operator in the electronic viewfinder 54.

  The operator transmits various operation information to the system controller 50 via the second operation unit 52, and the system controller 50 controls the entire VCR based on the operation information.

  The image data multiplexed by the video processing unit 34 is output to the second memory 40 and temporarily stored. The operation of the first memory 38 and the second memory 40 is controlled by the system controller 50 via the first memory control circuit 46 and the second memory control circuit 48, respectively.

  The first data selector 42 selects the data from the first memory 38 and the second memory 40 described above and transfers the selected data to the second 1394 interface 44, or the data from the second 1394 interface 44. Is transferred to either the first memory 38 or the second memory 40.

  By the above operation, compressed image data and uncompressed image data can be selected and output from the second 1394 interface 44 in the VCR 28 by the operator.

  The second 1394 interface 44 receives command data for controlling the VCR 28 through the 1394 serial bus. The received command data is input to the system controller 50 through the first data selector 42.

  The system controller 50 creates response data for the command data and sends the data to the 1394 serial bus through the first data selector 42 and the second 1394 interface 44.

  In the present embodiment, for example, the printer 60 operates as an image printout apparatus. The third 1394 interface 62 receives an image signal transferred onto the 1394 serial bus and command data for controlling the printer 60 through the 1394 serial bus. The third 1394 interface 62 transmits response data for the command.

  The received image data is input to the second decoder 70 through the second data selector 64. The second decoder 70 decodes the image data and outputs it to the image processing unit 74. The image processing unit 74 temporarily stores the decoded image data in the third memory 72.

  On the other hand, the received command data is input to the printer controller 68 through the second data selector 64. The printer controller 68 performs various printing-related controls such as paper feed control by the driver 76 and position control of the printer head 78 based on the command data.

  In addition, the printer controller 68 transmits the image data temporarily stored in the third memory 72 as print data to the printer head 78 to perform a printing operation. As described above, the first to third 1394 interfaces 14, 44, 62 according to the present embodiment each constitute a 1394 serial bus node.

  The first 1394 interface 14 operates as a control node or a controller, the second 1394 interface 44 operates as a source node of image data, and the third 1394 interface 44 operates as a destination node.

  The operation of each node according to the present embodiment will be described below with reference to FIG. In FIG. 2, 200 is a controller, 202 is a source node, 204 is a destination node, 206 is a subunit inside the source node, 208 is an object such as image data, 210 is a first memory space inside the destination node, 212 Is the first connection, 214 is the nth memory space of the destination, and 216 is the nth connection.

The controller 200 is a node that manages a connection ID for establishing a connection between the source node 202 that performs data transfer and the destination node 204.

  The controller 200 may be a node independent of the source node 202 and the destination node 204, or the source node or the destination node and the controller may be the same. In the latter case, a transaction between the controller, which is the same node as the controller or the source node or the destination node, is unnecessary.

  In this embodiment, an example in which the controller 200 exists in a node different from the source node 202 and the destination node 204 is shown. In the communication apparatus according to the present embodiment, a plurality of connections can be established.

  The source node 202 writes the object 208 such as image data from the internal subunit 206 into the first memory space 210 inside the destination node through the first connection 212, for example. In addition, data exchange through the above-described connection is performed using, for example, an Asynchronous packet.

  Next, the operation of each node of the controller 200, the source node 202, and the destination node 204 will be described with reference to FIG. The controller transmits a data packet for connection to the source node and the destination node selected by the user.

  This packet is an Asynchronous packet, and the connection ID for identifying this connection is written in the payload. Following this packet, the controller sends a send command packet to the source node. When the transmission command packet is received, the source node and the destination node perform a broadcast transaction using the assigned connection ID and start data transfer.

  When the data transfer ends, the source sends a broadcast packet indicating segment end, and the controller that receives this packet releases the connection ID, and the data transfer ends.

  Here, the connection ID indicates a logical connection between the source node and the destination node, and has a meaning of discriminating a plurality of objects transmitted from the subunits included in the source node. Therefore, when a plurality of different objects are transmitted from the same source node to the same destination node, the destination node can discriminate each object by detecting the connection ID included in the Asynchronous packet. .

  Further, even when the same object is transmitted from the same source node to a plurality of different destination nodes, each destination node can determine the Asynchronous packet to be received by this connection ID.

  Upon receiving the connection ID notification packet and the transmission command packet from the controller, the source node transmits an Asynchronous broadcast packet for an inquiry to the destination node.

  In this packet, the connection ID designated by the controller is written. The destination node receives this packet and sends out a response broadcast packet. The same connection ID is also written in this packet, and the source node compares this ID to identify whether the packet is addressed to this source node.

  In the response packet, the buffer size and the offset address of the destination node are written, and subsequent data transfer is performed by a write transaction for the address.

  The source node writes to the offset address received from the destination node using an Asynchronous broadcast packet. In this packet, the connection ID and the data sequence number are written.

  After transmitting the broadcast packet, the source node waits for a response from the destination node. From the destination node, a response packet in which the connection ID and sequence number are written is transmitted as an Asynchronous broadcast packet. Upon receiving this packet, the source node increments the sequence number and transmits the next data in the same manner.

  By repeating this procedure, the source node performs data transfer. The maximum time for waiting for a response from the destination node is determined in advance, and if the response does not return after that time, the same data is retransmitted using the same sequence number. If a response packet for a retransmission request is transmitted from the destination node, the data of the specified sequence number is retransmitted by broadcasting. When the transfer of all data is completed, the source node transmits a broadcast packet indicating segment end and ends the data transfer.

  Upon receiving the connection ID notification packet from the controller, the destination node waits for an Asynchronous broadcast packet for an inquiry from the source node. The destination node that has received the broadcast packet collates the connection ID written in the packet with the connection ID notified from the controller, and determines whether this packet is a packet from the source node.

  When receiving the inquiry packet from the source node, the destination node broadcasts a response packet in which the connection ID, the buffer size for data reception and the offset address are written. Data from the source node is written to this address.

  When data is written from the source node, the destination node verifies the connection ID in the payload. If this ID matches the ID notified from the controller, data is received, and a response packet in which the connection ID and the sequence number in the received data are written is transmitted by broadcast. When inconsistency is detected in the sequence number of the received data, a response indicating a retransmission request can be sent out and the data can be requested again from the source node. When all the data transfer is completed, a broadcast packet indicating segment end is transmitted from the source node. When this packet is received, the data transfer process is terminated.

  In order to transfer data reliably, it is desirable that the data transfer be resumed promptly even when the data transfer is interrupted due to the occurrence of a bus reset or some error. In the present embodiment, this problem is solved by providing a retransmission request procedure.

Next, the retransmission request procedure will be described with reference to FIG.
If a bus reset occurs during data transfer, each node follows the procedure specified by the standard.For example, if the data transfer is interrupted when the sequence number is i, each node first starts the procedure specified by the standard. To rebuild the bus.

  After the bus reconstruction is completed, the destination node transmits a resend request packet (resend request) in which the connection ID and the sequence number i are written as a broadcast packet. If the data transfer can be resumed, the source node returns an ack response. Thereafter, the source node collates the connection ID of the received packet and sequentially transmits the data of the data sequence starting from the requested sequence number, that is, the sequence number (i + 1) starting from the broadcast packet.

  According to the above-described procedure, the source node, the destination node, and the controller node can restart the subsequent data transfer easily and reliably even if the data transfer is interrupted without considering the node ID. Further, as described above, the present embodiment has an effect that the control procedure of the controller can be simplified even when the data transfer is interrupted.

  Next, the aforementioned asynchronous packet will be described with reference to FIG. The Asynchronous packet according to the present embodiment is, for example, a data packet in units of 4 bytes (32 bits, hereinafter referred to as a quadlet). In the Asynchronous packet, the first 16 bits is a destination ID field, which indicates the node ID of the reception destination.

  In the 1394-1995 standard, the first 16 bits indicate the upper 10 bits indicate a destination bus ID, and the lower 6 bits indicate a destination physical ID, a so-called node ID. When the upper 10 bits are 3FFh, this indicates transmission to the local bus, and from 0h to 3Fe h indicates transmission to other buses.

  When the lower 6 bits are 3Fh, it indicates a broadcast packet, and from 0 h to 3Eh indicates transmission to a specific node ID. When broadcasting to the local bus as in the present embodiment, the value of this field is FFFF 16.

The next 6 bits field is a transaction label (tl) field, which is a tag unique to each transaction.
The next 2 bits field is a retry (rt) code, which specifies whether the packet will retry.

  The next 4 bits field is the transaction code (tcode). tcode specifies the format of the packet and the type of transaction that must be performed.

In this embodiment, for example, a transaction of a data block write request whose value is 0001 2 is used.
The next 4 bits field is a priority (pri) field, which specifies the priority. In this embodiment, since an Asynchronous packet is used, the value of this field is 00002.

The next 16 bits are a source ID field, which indicates the node ID of the transmitting side.
The next 48 bits is the destination offset field, and the lower 48 bits of the packet destination node address are specified by this field.

The next 16 bits is a data length field, which indicates the length of the data field described later in bytes.
The next 16 bits are an extended tcode field, and this value is $ 0000 16 $ in the data block write request transaction used in this embodiment.

The next 32 bits are a header CRC field. The above-described destination ID field to extended tcode field are called a packet header and are used for error detection of the header packet.
The next field is a variable length data field, which is referred to as the packet payload. In the present embodiment, if the data field is not a multiple of a quadlet, the bits that are less than the quadlet are filled with 0.

  The next 32 bits field is a data CRC field, which is used for error detection of the data field in the same manner as the header CRC field. FIG. 5 is a diagram in which fixed data is added in the Asynchronous packet header used in the present embodiment in the above-described field. FIG. 6 is a diagram showing the structure of the data field of the Asynchronous packet used in this embodiment.

  In FIG. 6, data having the same function as in FIG. 4 will not be described. The first six quadlets are header information, in which the connection ID for identifying the connection is written.

  The sixth and subsequent quadlets are variable-length data blocks. In the present embodiment, when the data block is not a multiple of a quadlet, bits less than the quadlet are filled with 0.

  FIG. 7 shows the structure of the header information. The first two quadlets are the worldwide unique ID of the control node, and the source and destination identify the control node that established the connection based on the data. This worldwide unique ID conforms to the 1394-1995 standard.

Here, a worldwide unique ID based on 1394-1995 is used to identify individual control nodes, but any unique information that can identify individual nodes that do not change even if a bus reset occurs. Anything.
The next 16 bits are the above-described connection ID (connection ID) field, which identifies the connection by the data.

  Even when a plurality of controllers set the same connection ID, each node identifies an absolute logical connection based on the unique ID of the control node and the connection ID.

  In addition, each controller may allow duplication of connection ID numbers set by other controllers, and the controllers may use IDs set by other controllers.

  The next 8 bits are a protocol type field, which indicates a data exchange procedure using the header information. In the figure, it is shown as Reserved.

  For example, a value of 01 16 is used in the exchange procedure of the present embodiment. The next 8 bits are a control flags field in which control data is written. The most significant bit of the control flag field is, for example, a resend request flag. When the value of this bit is 1, it indicates that a data resend request has occurred.

  The next 16 bits are a sequence number field. As described above, in the sequence number field, a continuous value is used for data packets transmitted and received with a specific connection ID. The destination node monitors significant continuity of data by the sequence number field, and if a mismatch occurs, makes a retransmission request to the source node.

  The next 16 bits are a reconfirmation number field. This field is meaningful only when the value of the above-mentioned retransmission request flag is 1.

  When the value of the above-mentioned retransmission request flag is 1, this field indicates the sequence number of the start packet for which a retransmission request has occurred. The next 16 bits indicate the buffer size of the destination node. The next 48 bits indicate an offset address of a virtual address space (CRS space) compliant with the destination node IEEE1212 standard.

(Explanation of terms)
In the above-described embodiment, the following segment refers to a segment obtained by dividing the source node data by the value obtained by subtracting the header size value provided in the payload from the payload data value. Is called segment data. The segment data size is called segment data size.

  FIG. 9 shows a configuration in which two controllers set the same connection ID on the network. The controller node 1 in FIG. 9 has a node unique identification ID that does not change even if a bus reset or the like occurs. Here, it is assumed that the IEEE1394-1995 standard worldwide unique ID = 1.

  Similarly, the controller node 2 in the figure indicates that the controller node 2 has a node-unique identification ID that does not change even when a bus reset or the like occurs as in the controller node 1. Here, it is assumed that the worldwide unique ID of the IEEE1394-1995 standard is 4. Each controller sets a logical connection between the source destinations, and here, each logical connection ID is 0.

  Thus, even when each controller sets the same connection ID, there is no need to negotiate so that connection IDs do not overlap between control nodes.

  In connection setting, the controller notifies the connection ID and the controller node unique identification ID between the source destinations in advance. Each of the source and destination identifies here the controller that established the connection by the above procedure.

FIG. 10 shows a rough flow between the entire controller, source, and destination of the present embodiment supplementing the flow described in FIG. 3 (a).
(1) The controller first asks each destination for the max_rec size that conforms to the IEEE1394-1995 standard indicating the payload size of the largest Asynchronous Write transaction that each destination can accept, and at the same time, a unique connection ID set by the controller. Announce. Each destination notifies the max rec size in response to the command from the controller, and returns a response that the connection ID is set.

(2) Next, the controller sets the unique connection ID set by the controller with respect to the source, the total number N of destinations to which the controller logically connects between the source and the destination, and the broadcast asynchronous transmitted by the source. Announce the size of the payload of the Write transaction. Regarding the size of the payload notified from the controller to the source node, the smallest max rec size among the max rec sizes from each destination is the payload size from the source node.

  The source node selects the data size of one segment as the data size obtained by subtracting only the header size of the fixed data size provided in the payload of each Asynchronous Write transaction from the payload size from the controller. The created object.

  Here, the controller notifies the source of the payload data size, and the source node calculates the segment data size. However, the controller may notify the source node of the result of calculating the segment size in advance. Good. In response to the command from the controller, the source returns a response indicating that each has been set.

(3) The controller selects one object from the object data of the source desired to be transmitted to the source. The source returns to the controller that the object has been selected as a response. The selected object may be a still image or a moving image. Moreover, text data and binary data may be used.

(4) When the controller knows that the source can send an object in response to the response from the source, the controller sends a command instructing the source to start sending the selected object to the source.

(5) Upon receiving the transmission start command from the controller, the source starts transmission of the selected object.

(6) When the transmission of the object from the source is completed, the controller releases the selected object to the source.

(7) At this time, the controller repeats the procedure (3) to the procedure (6) if it is desired to transmit another object.

(8) When all the objects have been transmitted, the controller may release the previously set unique connection ID.

  FIG. 11 shows a configuration in which one controller sets the same connection ID on one network between one source and N destinations. Here, the unique connection ID is FFFF (h), but other numbers may be used. The controller performs the procedure (1) of the entire flow shown in FIG. 10 for each destination and repeats it N times for convenience.

  FIG. 12 shows a case where, in the network configuration as shown in FIG. 11, each destination has the same reception buffer size, and the object data size is equal to the reception buffer. Here, for simplicity, the number of destinations is N = 3. The source has already been notified from the controller that the number of destinations connected by the same connection ID is 3 from the controller.

(A) When a transmission start command from the controller is transmitted to the source, the source transmits a connection request according to the procedure described in FIG.
(B) Each of the three destinations returns an Ack response with its own reception buffer size added when reception preparation is completed.
(C) After confirming that three Acks have returned, the source divides the object into the specified payload size from the reception buffer size in the Ack response until the buffer size of the destination is reached. Send.

(D) A segment end flag indicating the end of the segment is set and transmitted in the last segment where all data has been transmitted.
(E) Upon receiving the segment end packet, each destination returns a segment end receive response indicating that all the data has been received.
(F) The controller and the source recognize that the segment end receive response has returned from all the destinations, and recognize that the data transfer has been completed.

  FIG. 13 shows a model of object data transfer described in FIG. In this figure, the object data is a still image with a data size of 128 Kbytes, and the segment size is an example showing that the segment size is divided into 500 by 256 bytes and transferred to the destination.

  FIG. 14 shows a flow of data transfer in the network shown in FIG. 11 in which each of the three destinations has different reception buffer sizes. Here, for simplicity, the number of destinations is N = 3. The source has already been notified from the controller that the number of destinations connected by the same connection ID is 3 from the controller.

(G) When a transmission start command from the controller is transmitted to the source, the source transmits a connection request according to the procedure described in FIG.
(H) Each of the three destinations returns an Ack response with its own reception buffer size added when reception preparation is completed.

(Re) After confirming that the three Ack returned, the source divides the object into the specified payload size from the field indicating the reception buffer size in each Ack response, and It transmits until it reaches the minimum buffer size, and waits for the receive response from the destination having the minimum buffer size to be transmitted.
(Nu) Upon receiving a receive response from the destination having the smallest reception buffer, the source continues to transmit up to the buffer size of the destination node having the next largest reception buffer, and the receive response from the destination is transmitted. Wait for.

(L) Upon receiving a receive response from the destination, the source continues to transmit up to the buffer size of the destination node having the next largest reception buffer, and waits for a receive response from the destination to be transmitted. .
(W) When all the data has been transmitted, the source transmits the last segment with the segment end flag and waits until receiving a segment end receive response from each destination.

  (W) When all the segment end receive responses have been received, the controller and the source recognize that the data transmission has been completed. FIG. 15 shows the case of the different reception buffers shown in FIG. 14, where the number of destinations N = 2 for simplicity.

  Here, the source object is a still image having a data size of 128 Kbytes, but the data size is variable and is not specified. Also, the object may be not only a still image but also a moving image, text, binary data, or the like.

  The source divides the object into 500 segments with a segment size of 256 bytes and sends it up to the buffer size of destination # 1. The destination returns a receive response until the source continues to be the receive buffer for destination # 2. Continue sending. Here, the buffer size of the destination of # 2 is twice the buffer size of # 1, but the buffer size between the destinations is not mutually defined.

  The destination of # 1 will conveniently return 3 send / receive responses, and the destination of # 2 will return 1 send / receive response.

(Second Embodiment)
This embodiment relates to broadcast in multicast.
In the first embodiment shown in FIG. 5, in the Asynchronous Write packet, the first 16 bits are a destination ID field, and this field indicates a destination node ID. When broadcasting to the local bus as in the first embodiment, the value of this field is FFFF 16.

  FIG. 16 shows the destination ID field. As described above, in the IEEE1394-1995 standard, the first 16 bits of this first field indicate the destination bus ID, and the lower 6 bits indicate a destination physical ID, a so-called node ID.

  When the upper 10 bits are 3FFh, this indicates transmission to the local bus, and from 0h to 3Feh indicates transmission to other buses. When the lower 6 bits are 3Fh, it indicates a broadcast packet, and from 0h to 3Eh indicates transmission to a specific node ID.

  Here, the total of 16 bits of the upper 10-bit destination Bus ID and lower-order destination Physical ID defined using one specific value from 0h to 3FEh used to indicate transmission to other buses. This is defined as a multicast ID. In the second embodiment, the lower 6 bits use 3Fh indicating broadcast. When the lower 6 bits are 3Fh, it is defined as broadcast ID.

  In the second embodiment, among the first 16-bit fields described above, the 10-bit destination Bus ID is conventionally used to indicate transmission to other buses from 0h to 3FEh. One specific value is dedicated to multicast data transfer, and the lower 6 bits use a destination physical ID of 3Fh indicating a so-called node ID as a broadcast packet. An example of this is shown in FIG.

(Third embodiment)
Here, in the second embodiment, the high-order 10-bit destination bus ID defined using one specific value from 0h to 3FEh used to indicate transmission to other buses. In the same way as in the second embodiment, a multicast ID is defined by a field of a total of 16 bits that is a combination of the lower destination physical ID and the lower destination physical ID.

  In the third embodiment, among the first 16-bit fields described above, the lower 6-bit destination Physical ID shown in the second embodiment uses a value indicating an ID addressed to a specific node. . In 1394, this indicates the node ID determined after the bus reset. It takes a value from 0h to 3Eh and can specify 63 node IDs for convenience.

  Here, since the upper 10 bits are designated as a destination bus ID dedicated to multicast data transfer as shown in the second embodiment, the ID shown by the lower 6 bits is a specific for multicast data transfer. The node ID is indicated. This is shown in FIG.

  As in the first embodiment, as shown in FIG. 10, the controller notifies the source and the destination of the multicast ID indicated by 16 bits described in the present embodiment in advance in connection setting. . In addition, since the upper 10 bits specify multicast because the multicast is specified, it is possible to notify only the lower 6 bits.

  At the same time, the controller notifies the source and destination of the 48 bits destination offset field of the CSR space of the destination. The controller can specify a 48 bits destination offset field in multiple arbitrary CSR spaces for each multicast ID.

  The controller may have a 48 bits destination offset field in the CSR space of the destination as a table. The controller sets a connection between the source and destination for each 48 bits destination offset field in the CSR space of these multiple destinations.

  As described above, the lower 48 bits of the packet receiving node address are designated by this field. In this way, each destination recognizes the 6-bit ID set by the controller and the 48-bit destination offset field in the CSR space and captures the data.

  The controller manages the combination of the multicast ID and the offset address as the connection ID for the multicast ID and the offset address of the destination. FIG. 19 shows an example of a table format. FIG. 20 shows a connection table held by the controller when the controller has set five independent connections between the source and destination.

  Here, it can be seen that the controller secures three multicast IDs, and a different destination offset address is set for each multicast ID = 3FE00 (h).

  One destination offset address is set for multicast ID = 3FE01 (h). Similarly, for the multicast ID = 3fE04 (h), one destination offset address is set.

  In this way, a mechanism is provided for setting a plurality of destination offset addresses for one multicast ID. For this reason, even if the multicast ID is only 63, a plurality of connections can be set.

  The response packet sent back to the source from the destination is set with the 16-bit multicast ID and destination offset address set by the controller, written in the destination ID of Asynch Write shown in FIG. 4, and sent in the Asynchronous Write transaction. To do.

  The controller sets the 48-bit destination offset field in the CSR space of the source node for each connection in advance, and the destination node is notified of the 48-bit destination offset in the CSR space of the source node when setting the connection. Have already explained.

  In addition, the controller notifies the source and destination of the WWUID of the controller in the same manner as in the first embodiment and the second embodiment. In addition, the total number of destinations set for each connection ID with the same connection ID is 6 bits in word length, and the total number of connections for which connection setting has been completed is shown in the Total number of destination field.

  Even when a bus reset occurs by writing the connection ID managed by the controller in the field indicating the WWUID shown in FIG. 21 and using the multicast ID, the source and destination are as shown in the first embodiment. The connection can be automatically restored as shown in FIG.

(Fourth embodiment)
In this embodiment, the node having the multicast ID table is an isochronous resouce manager. The controller that sets the connection reads the multicast ID held at a specific offset address to the isochronous resource manager once with an asynchronous read transaction, and writes the desired multicast ID with a compare / swap lock transaction. To obtain the desired multicast ID.

  These procedures are the same as the acquisition procedure for Isochronous Ch in the IEEE1394-1995 standard. Similarly, when the node having the multicast ID is a ROOT node, the procedure for the controller to acquire the multicast ID is the same.

  Since the number of nodes managing the multicast ID is limited to one on the bus and the controller that desires the connection secures the ID to the node managing the multicast ID, the multicast IDs overlap. Nothing will happen.

  For each connection, a multicast ID and a 48 bits destination offset of the CSR space of each of the source and destination are specified. Therefore, the connection ID in the header provided in the payload as shown in FIG. , WWUID is added and the source and destination may not be added. A header in the case of the fourth embodiment is shown in FIG.

  The example of the header shown in FIG. 23 shows a case where the controller inquires of the destination about the buffer size of the destination and notifies the source in the general flow described in FIG. In this case, it is not necessary to provide a field indicating the destination buffer size in the header in each payload.

  The example shown in FIG. 24 shows a connection configuration between the controller and the source destination. The controller sets a connection between the source and the destination and is managed by the connection ID. As for the source and destination, it is the same as in the first embodiment that the connection is determined based on the connection ID notified in advance.

  Each destination has a connection ID, a multicast ID, and an offset address set as a table, as shown in the figure. Although not shown in FIG. 24, it goes without saying that the source also has a similar table.

  FIG. 24 shows a connection configuration between the controller and the source destination. As for the source and destination, it is the same as in the first embodiment that the connection is determined based on the connection ID notified in advance.

  The controller indicates that a connection is set up between one source and N destinations. The controller has as a table all connections currently set by the controller.

  The controller sets connection with the source node for a total of three nodes of destination nodes 0, 1, and 2 with connection ID = 0 (h). The total number of destinations connected by the same connection ID = 3 (h) is recorded in the Total number of destination field of the table. In addition, a connection is set to the destination node #n with another connection ID = 4 (h). Similarly, the total number of connected destinations = 1 (h) is recorded in the Total nuber of destination field of the table.

  Each of the destination nodes 0, 1 and 2 shown in FIG. 24 indicates that the destination has a connection set in the destination by the controller as a table.

  As shown in FIG. 24, since the same connection ID is set for each of the destination nodes 0, 1, and 2, all the connection tables of the destination nodes 0, 1, and 2 are the same. .

  When the source transmits the same data to the destination nodes 0, 1, and 2 at the same time, the connection ID = 0 (h) in the connection table of the source changes to the destination ID in the header of the Asynchronous Write packet. In the payload defined in the present embodiment, a multicast ID of 0 (h) = 3FE00 (h) is added, and the destination offset address field = FFFF E000 0000 (h) is also added to the destination offset address. The same Asynchoronous White packet is transmitted with the connection ID = 0 (h) added to the header.

  At the time of reception, the destination nodes 0, 1, and 2 compare the multicast ID = 3FE00 (h) with the destination ID = 3FE00 (h) of the acquired Asynchronous Write packet from the connection table that they have, and are the same. Therefore, the data is captured as a packet addressed to itself.

  Next, the destination offset address of the same packet is compared with the destination offset address field of its own table = FFFF E000 0000 (h). And the data is taken into the internal buffer for connection ID = 0 (h).

  The destination node #n compares the multicast ID = 3FE04 (h) with the destination ID = 3FE00 (h) of the captured Asynchronous Write packet from its own connection table, and captures data as a packet because they are not the same. Absent.

  Further, when data is transmitted from the source to the destination node #n, the connection ID = 4 (h) from the connection ID = 4 (h) in the connection table of the source to the destination ID in the header of the Asynchronous Write packet. ) Multicast ID = 3FE04 (h) is added, and the destination offset address field = FFFF E000 0000 (h) is also added to the destination offset address, and a connection is made to the header in the payload defined in this proposal. Asynchronous Write packet is transmitted with ID = 4 (h).

  The reception destination node #n compares the multicast ID = 3FE04 (h) with the destination ID = 3FE04 (h) of the acquired Asynchronous Write packet from its own connection table. Next, the destination offset address of the packet is compared with the destination offset address field = FFFF E000 0000 (h) of its own table, and since it is the same, data is fetched as a packet addressed to itself, and connection ID = 4 ( h) Load the data for the buffer.

  At this time, the destination nodes 0, 1, and 2 compare multicast ID = 3FE00 (h) with the destination ID = 3FE04 (h) of the acquired Asynchronous Write packet from their connection tables, and are not the same. Do not capture data as packets. Although not shown in FIG. 24, it goes without saying that the source also has a similar table.

  FIG. 25 shows a connection configuration between the controller and the source destination. As for the source and destination, it is the same as in the first embodiment that the connection is determined based on the connection ID notified in advance.

  The controller indicates that a plurality of different connections are set up between one source and one destination. The controller has as a table all connections currently set by the controller.

  The controller sets the connection with the source node for the destination node with a total of three connection IDs = 0 (h), 1 (h), and 2 (h). The total number of destinations connected by each connection ID = 1 (h) is recorded in each Total number of destination field of the table.

The destination node shown in FIG. 25 indicates that the controller has a connection set as the destination as a table.
As shown in FIG. 25, since the connection ID = 0 (h), 1 (h), 2 (h) is set in the destination node, the connection table of the destination node is multicast for each connection ID. The ID is the same, but the destination offset address is different.

The source may send different data for each connection to the destination node. Hereinafter, such a case will be described.
First, when data is transmitted using connection ID = 0 (h) in the connection table of the source, the multicast ID = 3FE00 (connection ID = 0 (h) is set as the destination ID of the header of the Asynchronous Write packet. h) and the destination offset address field = FFFF E000 0000 (h) of the table is added to the destination offset address, and the connection ID = 0 (h) is added to the header in the payload defined in the present embodiment. ) To send the same Asynchronous Write packet.

At the time of reception, the destination node compares the multicast ID = 3FE00 (h) with the destination ID = 3FE00 (h) of the acquired Asynchronous Write packet from its own connection table, and is the same. Capture data as packets. Next, the destination offset address of the packet is compared with the destination offset address field = FFFF E000 0000 (h) of its own table, and since it is the same as the connection ID = 0, it is determined that the connection is set. The data is taken into the buffer for connection ID = 0 (h).
Hereinafter, connection ID = 1 (h) and 2 (h) are processed in the same manner.

(Other embodiments of the present invention)
The present invention may be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.) or an apparatus composed of one device.

  In addition, software for realizing the functions of the above-described embodiments is provided to an apparatus or a computer in the system connected to the various devices so that the various devices are operated so as to realize the functions of the above-described embodiments. What is implemented by supplying the program code and operating the various devices in accordance with a program stored in a computer (CPU or MPU) of the system or apparatus is also included in the scope of the present invention.

  In this case, the program code of the software itself realizes the functions of the above-described embodiments, and the program code itself and means for supplying the program code to the computer, for example, the program code is stored. The storage medium constitutes the present invention. As a storage medium for storing the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code supplied by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) or other application software in which the program code is running on the computer, etc. It goes without saying that the program code is also included in the embodiment of the present invention even when the functions of the above-described embodiment are realized in cooperation with each other.

  Further, after the supplied program code is stored in the memory provided in the function expansion board of the computer or the function expansion unit connected to the computer, the CPU provided in the function expansion board or function expansion unit based on the instruction of the program code Needless to say, the present invention includes a case where the functions of the above-described embodiment are realized by performing part or all of the actual processing.

It is a block diagram showing embodiment of this invention. It is a block diagram which shows operation | movement of each node which concerns on this invention. It is a figure which shows the diagram which shows transmission / reception of the command in between each node which concerns on this invention, and data. It is a figure which shows the Asynchronous packet concerning this invention. It is a figure which shows the Asynchronous packet used by embodiment of this invention. It is a figure which shows the structure of the data field of Asynchronous packet used by embodiment of this invention. It is a figure which shows the structure of the header in the data field used by embodiment of this invention. It is a figure which shows a prior art example. It is a figure which shows the specific identification information which the control node used by embodiment of this invention has. It is a figure which shows the whole flow which supplements the flow demonstrated in FIG. 3A used by embodiment of this invention. It is a figure which shows the structure which one controller used by embodiment of this invention set the same connection ID on the network between one source and N destinations. It is a figure which shows the case where each destination used by embodiment of this invention has the same receiving buffer size, and object data size is equal to this receiving buffer. It is a figure which shows the model of transfer of the object data used by embodiment of this invention. It is a figure which shows the flow of the data transfer in the network in which each 3 destination used by embodiment of this invention has a different receiving buffer size. The case of different reception buffers used in the embodiment of the present invention is shown. Here, for simplicity, the number of destinations is set to N = 2. It is a figure which shows Asynchronous DestinationID shown by IEEE1394-1995. It is a figure which shows the example of broadcast ID in the multicast used by the 2nd Embodiment of this invention. It is a figure which shows multicast ID used by embodiment of this invention. It is a figure which shows the connection ID table which a controller, a source, and a target used in the 2nd-4th embodiment of this invention have. It is a figure which shows the connection ID table which the controller used by the 2nd-4th embodiment of this invention has. It is a figure which shows the header structure in the payload used by 1st-3rd embodiment of this invention. It is a figure which shows the header structure in the payload used in the 4th Embodiment of this invention. It is a figure which shows the header in the payload used by the 4th Embodiment of this invention. It is a figure which shows the table of connection ID, multicast ID, and destination offset address which a controller and a destination used in the 2nd-4th embodiment of this invention have. It is a figure which shows the connection structure of a controller and a source destination.

Explanation of symbols

10 computer
12 Processing unit (MPU)
14 First 1394 interface
16 First operation unit such as keyboard
18 First decoder
20 Display devices such as CRT displays
22 Hard disk
24 First memory
26 Computer internal bus such as PCI bus
28 VCR
30 Imaging optics
32 A / D converter
34 Video processing section
36 Compression / decompression circuit
38 First memory
40 second memory
42 First data selector
44 Second 1394 interface
46 First memory control circuit
48 Second memory control circuit
50 System controller
52 Second control section
54 Electronic viewfinder
56 D / A converter
58 Recording section
60 Printer
62 Third 1394 interface
64 Second data selector
66 Third control
68 Printer controller
70 Second decoder
72 Third memory
74 Image processor
76 drivers
78 Printer head
200 control nodes
202 source node
204 Destination node
206 Subunit in source node
208 Object such as image data
210 First memory space inside the destination node
212 First connection
214 nth memory space inside the destination node
216th connection

Claims (32)

In a data communication system composed of a plurality of devices,
Using first information indicating a virtual communication relationship constituted by N devices included in the plurality of devices and second information for determining information data communicated between the N devices. A data communication system for communicating the information data. The data communication system according to claim 1, wherein
The data communication system includes a management device having a function of managing the first and second information, and controls communication between the N devices using the management device. system. The data communication system according to claim 2, wherein
The data communication system, wherein the management device transmits the first and second information to each of the N devices. The data communication system according to claim 3,
The data management system, wherein the management device transmits unique ID information unique to the management device together with the first and second information to each of the N devices. The data communication system according to claim 4,
The data communication system, wherein the N devices identify management devices that have set the first and second information using the unique ID information. The data communication system according to any one of claims 2 to 5,
A data communication system, wherein the management device communicates with each of the N devices using an asynchronous transfer method compliant with the IEEE 1394 standard. The data communication system according to any one of claims 2 to 6,
The data communication system, wherein the management device manages additional information related to the first and second information using a table. The data communication system according to any one of claims 2 to 7,
The data communication system, wherein the N devices transmit the information data using a communication packet configured by the first and second information. The data communication system according to claim 8,
The data communication system, wherein the first information is stored in a header portion of the communication packet, and the second information is stored in a data portion of the communication packet. The data communication system according to any one of claims 2 to 9,
The data communication system, wherein the information data is stored in a memory space corresponding to the second information. The data communication system according to any one of claims 1 to 10,
The data communication system characterized in that the first information indicates a logical connection relationship constituted by one transmitting device and a plurality of receiving devices. The data communication system according to any one of claims 1 to 11,
The data communication system, wherein the second information is information for distinguishing each of a plurality of different information data communicated between the N devices. The data communication system according to any one of claims 1 to 12,
A data communication system, wherein information data output from each of the N devices is transferred to all devices constituting the data communication system. The data communication system according to any one of claims 1 to 13,
A data communication system, wherein information data output from each of the N devices is transferred using an Asynchronous transfer method compliant with the IEEE 1394 standard. The data communication system according to any one of claims 2 to 14,
The data communication system, wherein the management device ends communication of the information data by an end flag transmitted from the device that transmits the information data. The data communication system according to any one of claims 2 to 15,
The data communication system according to claim 1, wherein the virtual communication relationship is released by the management device or a device that receives the information data. The data communication system according to any one of claims 1 to 16,
The device that receives the information data, in response to the request constituting the virtual communication relationship, the size of the reception buffer, the address information indicating a predetermined area in the memory space, the sequential number indicating the data start pointer, the preparation A data communication system, wherein a packet including at least one piece of information indicating completion is transmitted. The data communication system according to any one of claims 1 to 17,
A data communication system, wherein the device that transmits the information data measures a response from the device that receives the information data for a predetermined period, and detects a communication abnormality in the period. The data communication system according to claim 18,
A data communication system, wherein a device that transmits the information data automatically starts a retransmission operation of the information data when the communication abnormality is detected. In a data communication system composed of a plurality of devices,
Information indicating a virtual communication relationship constituted by N devices included in the plurality of devices, information specifying a virtual memory space for storing information data communicated between the N devices, and A data communication system, wherein communication of the information data is performed using a computer. In a data communication system composed of a plurality of devices,
A data communication system, wherein a virtual communication environment is set using a plurality of ID information. In a data communication device connectable to a data communication system configured by a plurality of devices,
Setting first information indicating a virtual communication relationship constituted by N devices included in the plurality of devices and second information for determining information data communicated between the N devices Setting means to
A data communication apparatus comprising: communication means for performing communication of the information data using the first and second information set by the setting means. In a data communication device connectable to a data communication system configured by a plurality of devices,
Including first information indicating a virtual communication relationship constituted by N devices included in the plurality of devices, and second information for determining information data communicated between the N devices. Receiving means for receiving the information data;
A data communication unit comprising: a determination unit configured to determine whether the information data received by the reception unit is data transmitted to itself using the information of the first and second information; apparatus. In a data communication device connectable to a data communication system configured by a plurality of devices,
Information indicating a virtual communication relationship constituted by N devices included in the plurality of devices, information specifying a virtual memory space for storing information data communicated between the N devices, and A setting means for setting
A data communication apparatus comprising: communication means for performing communication of the information data using the first and second information set by the setting means. In a data communication device connectable to a data communication system configured by a plurality of devices,
Information indicating a virtual communication relationship constituted by N devices included in the plurality of devices, information specifying a virtual memory space for storing information data communicated between the N devices, and Receiving means for receiving information data including:
A data communication apparatus comprising: a determination unit configured to determine whether the information data received by the reception unit is data transmitted to itself using the first and second information. In a data communication method applicable to a data communication system composed of a plurality of devices,
Using first information indicating a virtual communication relationship constituted by N devices included in the plurality of devices and second information for determining information data communicated between the N devices. A data communication method characterized by performing communication of the information data. In a data communication method applicable to a data communication system composed of a plurality of devices,
Information indicating a virtual communication relationship constituted by N devices included in the plurality of devices, information specifying a virtual memory space for storing information data communicated between the N devices, and A data communication method comprising performing communication of the information data using a communication packet including: In a data communication method applicable to a data communication system composed of a plurality of devices,
A data communication method characterized by setting a virtual communication environment using a plurality of ID information. In a data communication method applicable to a data communication system composed of a plurality of devices,
Using first information indicating a virtual communication relationship constituted by N devices included in the plurality of devices and second information for determining information data communicated between the N devices. And determining whether or not the information data is data transmitted to itself. In a data communication method applicable to a data communication system composed of a plurality of devices,
Information indicating a virtual communication relationship constituted by N devices included in the plurality of devices, information specifying a virtual memory space for storing information data communicated between the N devices, and And determining whether or not the information data is data transmitted to itself.   A storage medium storing a program for causing a computer to function as each means according to any one of claims 22 to 25.   A storage medium storing a program for causing a computer to execute the procedure of the data communication method according to any one of claims 26 to 29.

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