JPH11313091A - System, device and method for data communication and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conveniently transfer data at a high speed and also to surely transfer the data by connecting between a transmitting device which transmits information data and a receiving device which receives the information data by using a connection ID, which shows logical connection, and performing communication. SOLUTION: 1st to 3rd 1394 interfaces 13, 44 and 62 operate as a control node, the source of image data and a node destination node. The control node sets an independent ID that is uniquely decided in a network, makes logical connection between the source and the node destination node and applies connection IDs respectively. After that, in handshake communication between the source and the node destination node, a connection ID number that is set by the controller is communicated by using a broadcast asynchronous transaction including a field in payload.

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, an apparatus, a method, and a storage medium, and more particularly, to a plurality of electronic devices using a data communication bus capable of communicating control signals and data in a mixed manner. Hereinafter, the present invention relates to an apparatus that has a system that connects devices and performs data communication between the devices.

[0002]

2. Description of the Related Art Among personal computer peripheral devices, hard disk drives and printers are most frequently used, and these peripheral devices are digital interfaces (hereinafter referred to as digital interfaces) which are typical general-purpose interfaces for small computers.
A connection between personal computers is made through SCSI (I / F) or the like, and data communication is performed.

A recording / reproducing device such as a digital camera or a digital video camera is one of the peripheral devices as an input means to a personal computer (hereinafter, referred to as a PC). Such images are imported to a PC and stored on a hard disk,
Or the technology in the field of color printing on a printer after editing on a PC has advanced, and the number of users is increasing.

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

FIG. 8 shows a conventional digital camera,
FIG. 2 shows a block diagram when a PC and a printer are connected. In FIG. 8, 801 is a digital camera, 802 is a personal computer (P
C) and 803 are printers. Further, 804 is a memory which is a recording unit of the digital camera, 805 is an image data decoding circuit, 806 is an image processing unit, 807 is a D / A converter, 808
Is the display section of the EVF, 809 is the digital camera digital
The I / O section 810 is a digital I / O section for a PC digital camera.

Reference numeral 811 denotes an operation unit such as a keyboard or mouse; 812, a decoding circuit for image data; 813, a display; 814, a hard disk device; 815, a memory such as a RAM; PCI bus, 818 is a digital I / F SCSI interface (board), 819 is
A SCSI interface of a printer connected to a PC via a SCSI cable, 820 is a memory, 821 is a printer head, 822 is a printer controller of a printer control unit, and 823 is a driver.

[0007] Images captured by the digital camera 801
2 and the procedure for output from the PC 802 to the printer 803 will be described. Digital camera 801 memory
When the image data stored in 804 is read, one of the read image data is decoded by a decoding circuit 805, and image processing for display is performed by an image processing circuit 806. The data is displayed on the EVF 808 via the A converter 807. On the other hand, digital I / O
From the O section 109, the digital I /
It reaches O section 810.

In the PC 802, the image data input from the digital I / O unit 810 is stored in the hard disk 814 when the PCI bus 817 is used as a bus for mutual transmission.
In the case of displaying, after being decoded by the decoding circuit 812, it is stored as a display image in the memory 815 and displayed on the display 81.
Displayed after being converted to analog signal by 3.

An operation input at the time of editing on the PC 802 is performed by the operation unit 81.
The processing from 1 is performed, and the whole process of PC802 is performed by MPU816. Also,
When printing an image, the image data is transmitted from the SCSI interface board 818 in the PC 802 via a SCSI cable and transmitted to the SCSI interface 81 in the printer 803.
9, is formed as a print image in the memory 820, and is controlled by the printer controller 822.
21 and the driver 823 operate to print the print image data read from the memory 820. The above is the procedure up to the point where the conventional image data is taken into the PC or printed.

As described above, conventionally, respective devices are connected to a PC serving as a host, and image data captured by a recording / reproducing apparatus is printed via the PC. AV equipment such as digital VTRs, TVs, tuners, etc., and personal computers (hereinafter, referred to as PCs) are connected to each other using an IEEEP1394 serial bus (hereinafter, referred to as 1394). Communication systems for transmitting and receiving digital audio signals and the like have been proposed.

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

Also, AV devices such as digital VTRs, TVs, tuners, etc., and personal computers (hereinafter, referred to as personal computers) are connected to each other using an IEEEP1394 serial bus (hereinafter, referred to as 1394). A communication system for transmitting and receiving digital video signals, digital audio signals, and the like has been proposed.

In these systems, since it is important to transfer data in real time, so-called synchronous communication (hereinafter referred to as isochronous communication) is used.
Data communication is being performed. Isochronous communication is a communication method suitable for real-time transmission because it is guaranteed that data can be transmitted without fail in each data transmission cycle.

The isochronous communication is a communication system using a channel number. By setting the receiving side to receive data of the channel number, one-to-N communication can be easily performed. The channel used for isochronous communication is Isochronous Resource Manag
An er node (hereinafter referred to as IRM) manages, and a transmitting node checks a register for channel management of the IRM, and secures a set channel number before transmitting data.

According to the conventional 1394-1995 standard, in order to perform Asynchronous communication, one-to-one communication is performed by designating a node address of a specific node, or data is transmitted to all nodes using a broadcast address. There was no other way. The broadcast is used not for application data transfer but for notification of a bus reset or the like, so that substantially only one-to-one data communication can be performed. Currently, the 1394.a standard uses As
An asynchronous Streaming Transfer is under discussion. This is because the form of the data bucket is the same as that of the isochronous packet, and the communication path uses asynchronous.
Similar to the isochronous communication, the communication method uses a channel number, and thus is a communication method suitable for 1: N communication.

In the case of transferring data using Asynchronous Streaming Transfer, similarly to the isochronous communication, the transmitting node checks the IRM channel management register and starts data transmission after securing the set channel number.

[0017]

However, as the problems of the digital interface mentioned in the prior art, SCSI has a low transfer data rate, a thick cable for parallel communication, and a peripheral device to be connected. There are restrictions on types, numbers, connection methods, etc., and inconveniences in many aspects have been pointed out.

In the case of the conventional 1394 communication, since synchronous communication is performed, it is not guaranteed that the communication is reliably performed. Therefore, there is a problem that the conventional 1394 isochronous communication cannot be used when data transfer is to be performed reliably.

In the conventional 1394 isochronous communication,
The total number of communications is also limited to 64, even if there is a vacancy in the communications band. For this reason, when it is desired to perform a large number of communications that do not require much communication bandwidth, the conventional 1394 isochrono
There was a problem that us communication could not be used.

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

The problems of the digital interface mentioned in the above-mentioned conventional example are: SCSI having a low transfer data rate, SCSI having a thick cable for parallel communication, types and number of peripheral devices to be connected, and connection. There are also restrictions on the method, and the inconvenience in many aspects has been pointed out.

In addition, the conventional 13-to-N communication is performed.
Although isochronous communication of 94 is suitable, in this case, it is necessary to secure a band before the transmission side starts transmission, and there is a problem that a limited band is occupied.

Now, consider a case where the same data is transmitted to a plurality of destination nodes # 1 to # 3 as shown in FIG. In such a case, as shown in FIG. 25, when the object held by the source node is divided into a plurality of segments and transmitted, as shown in the flow of FIG. 26, when the Asynchronous Write transaction is used, the Source Since it is necessary to write the same data to 1, # 2 and # 3 respectively,
There is a problem that the transaction procedure becomes complicated and the traffic on the bus increases.

Also, Asynchronous Streaming Transfer
In this case, there is no mechanism for returning a response from the destination node to the source node, and there is a problem that it is not guaranteed that transmitted data can be reliably received by the destination node.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. It is an object of the present invention to solve the inconvenience of the conventional communication system, to transfer data easily and at high speed, and to surely transfer data. As a first object.

A second object of the present invention is to perform a large number of communications simultaneously when a communication band is not used much.

Further, the present invention makes it possible to easily detect data lost due to interruption of data transfer, and to reliably and easily recover from the interruption of data transfer. As a third object.

A fourth object is to enable one-to-N communication with a simple procedure.

Further, Asynchronous Streaming Transfer
It is a fifth object of the present invention to ensure that data communication can be performed.

[0030]

SUMMARY OF THE INVENTION In order to solve the conventional problems, the present invention solves the problems of the conventional digital I / F as much as possible. General-purpose digital I / F (for example, IEEE1394-1
995 High Performance Serial Bus)
, Printers, other peripheral devices, and digital cameras and digital VTR recording / reproducing devices, etc., realize data communication between devices when connected in a network configuration, capture video data from the recording / reproducing device to a PC, and Data is transferred directly to a printer to perform printing. In such a network, Asynch
It provides a protocol for dividing each data into a plurality of pieces by a ronous transaction and transmitting the data.

In the data communication system of the present invention, in a data communication system constituted by a plurality of devices, a logical connection is established between a transmitting device for transmitting information data and a receiving device for receiving the information data. Connection I shown
It is characterized by connecting and communicating using D.

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 connection ID, and the plurality of management devices are used to manage the plurality of connection IDs. It is characterized in that a logical connection between devices is set.

Another feature of the data communication system of the present invention is that the management device includes a node ID included in a plurality of devices constituting the data communication system.
And transmitting the connection ID to the transmitting device and the receiving device using

Another feature of the data communication system of the present invention is that the management device is an IEEE 1
Using Asynchronous transfer method based on 394 standard,
It is characterized in that the connection ID is transmitted.

Another feature of the data communication system of the present invention is that communication between the transmitting device and the receiving device is performed using the connection ID.

Another feature of the data communication system of the present invention is that information data output from the transmitting device is transferred to all devices constituting the data communication system. .

Another feature of the data communication system of the present invention is that the information data output from the transmitting device is an Asynch compliant with the IEEE 1394 standard.
It is characterized by being transferred using the ronous transfer method.

Another feature of the data communication system according to the present invention is that the transmitting device is a communication system comprising a broadcast ID for designating all devices constituting the data communication system and the connection ID. The information data is transmitted using a packet.

Another feature of the data communication system of the present invention is that the management device is configured to be able to set a plurality of connection IDs between a pair of transmission device and reception device. It is characterized by:

Another feature of the data communication system of the present invention is that the management device includes a plurality of connections I between one transmission device and a plurality of reception devices.
D is settable.

Another feature of the data communication system of the present invention is that the management device manages additional information relating to the plurality of connection IDs using a table.

In another feature of the data communication system of the present invention, the management device recognizes that the communication of the information data has been completed based on an end flag transmitted from the transmission device. Features.

Another feature of the data communication system of the present invention is that the logical connection between the transmitting device and the receiving device is released by the management device or the receiving device. I have.

Another feature of the data communication system of the present invention is that the receiving device responds to the connection request of the transmitting device by receiving a buffer size, an offset address in a predetermined memory space, and starting data. A packet including a sequential number indicating a pointer of the above and information indicating completion of preparation is returned.

Another feature of the data communication system of the present invention is that the receiving device is provided with a bit indicating that data has been normally received.

Another feature of the data communication system of the present invention is that the transmitting device measures a response from the receiving device for a predetermined period, and detects a communication abnormality based on the period. .

Another feature of the data communication system of the present invention is that, when the transmitting device detects the communication abnormality, the transmitting device automatically starts the information data retransmission operation. I have.

Another feature of the data communication system of the present invention is that the amount of data that can be transmitted by the transmitting device at one time is equal to or less than the capacity of a communication buffer included in the receiving device. .

Another feature of the data communication system of the present invention is that the receiving device sends a response signal indicating completion of reception preparation every time the transmitting device receives data to be transmitted. It is characterized by transmitting to a transmitting device.

Another feature of the data communication system of the present invention is that, after the communication buffer is filled, the receiving device sends a response signal indicating completion of reception preparation to the transmitting device. It is characterized by being transmitted to.

Another feature of the data communication system of the present invention is that the transmitting device waits for data transmission to the receiving device at least until a response signal is received from the receiving device. It is characterized by doing.

Another feature of the data communication system of the present invention is that, in a data communication system composed of a plurality of devices, communication performed asynchronously between logically connected devices is performed by the data communication system. It is characterized in that it is performed using a broadcast ID designating all of a plurality of devices constituting a communication system.

Another feature of the data communication system of the present invention is that the communication asynchronously performed with respect to the predetermined communication cycle is an asynchronous transfer system conforming to the IEEE 1394 standard. .

Another feature of the data communication system of the present invention is that a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing the communication of the information data. In the data communication system including, the initial setting in the communication of the information data is performed using the transmitting device, the receiving device, and the management device, and the communication of the information data started after the initial setting is performed with the transmitting device. It is characterized in that it is performed using the receiving device.

Another feature of the data communication system of the present invention is that a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing the communication of the information data. In the data communication system including, the transmitting device, the receiving device, and the management device set a connection ID indicating a logical connection of the communication of the information data, the transmitting device and the receiving device, The communication of the information data is performed using the connection ID.

Another feature of the data communication system of the present invention is that in a data communication system including a transmitting device for transmitting information data and a receiving device for receiving the information data, the receiving device includes: The transmission device is notified to a predetermined memory space of the reception device, and the transmission device transmits the information data together with data designating the predetermined memory space.

[0057] A data communication apparatus according to the present invention is a data communication apparatus connectable to a communication system constituted by a plurality of devices, wherein a data transmission apparatus transmits information data and a reception apparatus receives the information data. It is characterized by comprising storage means for storing a connection ID indicating a logical connection of communication, and transmission means for transmitting the information data using the connection ID stored in the storage means.

Another feature of the data communication device of the present invention is that in a data communication device connectable to a communication system including a plurality of devices, a transmitting device for transmitting information data, ID indicating the logical connection of communication with the receiving device that receives
And receiving means for receiving information data output on the communication system using the connection ID stored in the storage means.

Further, the features of the data communication method of the present invention include a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing the communication of the information data. In a data communication method applicable to a data communication system, an initial setting in the communication of the information data is performed using the transmitting device, the receiving device, and the management device, and the information data started after the initial setting. Is performed using the transmitting device and the receiving device.

Another feature of the data communication method of the present invention is that a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing the communication of the information data. In a data communication method applicable to a data communication system including, the transmitting device, the receiving device, and the management device set a connection ID indicating a logical connection of the communication of the information data, and the transmitting device The receiving device communicates the information data using the connection ID.

Another feature of the data communication method of the present invention is that the data communication method applicable to a data communication system including a transmitting device for transmitting information data and a receiving device for receiving the information data. Wherein the information device notifies the transmitting device to a predetermined memory space of the receiving device, and transmits the information data together with data specified in the predetermined memory space.

Another feature of the data communication method of the present invention is that in a data communication method applicable to a data system composed of a plurality of devices, the data communication method is performed asynchronously between logically connected devices. The communication is performed using a broadcast ID designating all of a plurality of devices constituting the data communication system.

A feature of the storage medium of the present invention is that a program for causing a computer to execute the procedure of the data communication method is stored.

Another feature of the data communication system of the present invention is that, in order to solve the conventional problems, the present invention solves the problems of the conventional digital I / F as much as possible. Using a general-purpose digital I / F that is integrated into digital equipment, it can be used for personal computers PCs, printers, other peripheral devices, digital cameras and digital cameras.
Realizes data communication between devices when a VTR recording / reproducing device is connected in a network configuration, captures video data and other data from the recording / reproducing device to a PC, and transfers video data directly to a printer for printing. Asynchro data in various networks
Nous Streaming Transfer provides a protocol that divides each data into multiple and transmits them.

The controller node is an Asynchronous Str
Channel number used for eaming Transfer and connection to establish logical connection for data communication
When the ID is managed and the connection is set, the source node and the destination node are notified of the channel number and the connection ID.

The source node sets the designated channel
After securing from the IRM, the notified connection ID data is added to the payload, and data transmission is started using the notified channel. The destination node receives the Asynchronous Streaming packet of the notified channel, checks the connection ID in the packet, and if the ID is the same as the ID notified to itself, processes the received data.

To ensure data transfer, data indicating the sequence number of the packet is added to the data packet. If the destination node detects a mismatch of the sequence number in the received packet, the data is transmitted to the source node. The source node transmits a retransmission request packet, and retransmits the specified data.

Then, the data communication system of the present invention
In a data communication system including a transmitting device that transmits information data and one or more receiving devices that receive the information data, the transmitting device and the one or more receiving devices include:
The communication of the information data is performed using channel ID information indicating a predetermined channel allocated on a transmission path and connection ID information indicating a logical connection between the transmitting device and the one or more receiving devices. It is characterized by performing.
Another feature of the data communication system of the present invention is that the transmitting device packetizes the information data into one or more communication packets and sequentially transmits the communication packets. Another feature of the data communication system of the present invention is that the channel ID information is stored in a header part of the communication packet, and the connection ID information is stored in a data part of the communication packet. It is characterized by. Also,
Another feature of the data communication system of the present invention is that the transmitting device stores number information indicating an order of the communication packet in each of the communication packets. Another feature of the data communication system of the present invention is that the channel ID information and the connection ID information are set by a management device that manages communication of the information data. Another feature of the data communication system of the present invention is that the transmitting device sets the channel ID information and the connection ID information based on a predetermined communication protocol. Another feature of the data communication system of the present invention is that the transmission device performs the retransmission processing of the information data according to a change in a connection configuration of the data communication system. Further, as another feature of the data communication system of the present invention, the receiving device receives information data transmitted using predetermined channel ID information, and receives the connection ID information included in the information data. The information data is stored in an internal buffer on the basis of the information data. Another feature of the data communication system of the present invention is that the channel ID information is an IEEE
Isochronous Resource Manag based on 1394-1995 standard
It is characterized by being managed by er. Another feature of the data communication system of the present invention is that the information data is broadcasted on the data communication system. Another feature of the data communication system of the present invention is that the information data is an Asynchrono compliant with the IEEE1394.a standard.
It is characterized by being packetized into us Streaming packet format.

Another feature of the data communication device of the present invention is that the data communication device includes a transmitting device for transmitting information data and one or more receiving devices for receiving the information data. In the communication device, a channel ID indicating a predetermined channel allocated on the transmission path
Setting means for setting information and connection ID information indicating a logical connection between the transmitting apparatus and the one or more receiving apparatuses; and the channel ID information and the connection ID set by the setting means. Communication means for communicating the information data using information.

Another feature of the communication method of the present invention is that in a data communication system including a transmission device for transmitting information data and one or more reception devices for receiving the information data, Channel ID information indicating a predetermined channel assigned to the transmitting device,
The information data is communicated using connection ID information indicating a logical connection with one or more receiving apparatuses.

[0071]

The controller node sets an independent connection ID uniquely determined in the network, establishes a logical connection between the source and destination nodes, and assigns the connection ID to each logical connection. Thereafter, in handshake communication between the source and destination nodes, communication is performed using a so-called broadcast asynchronous transaction that includes a connection ID number set by the controller 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 the connections 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, upon completion of preparation for receiving data, receives information on buffer size that can be received and start of the data packet. It includes a data sequence number indicating the order, sets the Ack bit, and performs communication using a so-called broadcast asynchronous transaction.

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

By performing data transfer between the source and the destination using the channel number and the connection I / D data set by the controller node, a bus reset occurs and the node I / D of each node changes. However, data transfer can be resumed by a simple procedure. Further, one-to-N communication can be performed by a simple procedure without occupying a band.

When a re-data packet is lost due to an error or the like, the destination requests retransmission of the missing packet, and data communication can be reliably performed.

[0076]

Embodiments of the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 10 denotes a computer (hereinafter, referred to as a computer), 12 denotes an arithmetic processing unit (MPU), 14 denotes a first 1394 interface, 16 denotes a first operation unit such as a keyboard (operation), and 18 denotes a first operation unit. One decoder (decode), 20 is a display device (display) such as a CRT display, 22 is a hard disk (HD), 24 is a first memory (memory), which is provided as an internal memory of the computer 10 according to the present embodiment. It is what is being done. 26 is PCI
It is a computer internal bus such as a bus.

Reference numeral 28 denotes a VCR, and reference numeral 30 denotes an image pickup optical system (o
pt), 32 is an analog-to-digital (A / D) converter, 34 is a video processing unit, 36 is a compression / expansion circuit (compres
sion), 38 is the first memory, 40 is the second memory
(memory), 42 is the first data selector
, 44 is a second 1394 interface, 46 is a first memory control circuit (memory control), 48 is a second memory control circuit (memory control), 50 is a system controller (syste
m controller), 52 is a second operation unit (operation), 54 is a finder (EVF), 56 is a D / A converter, and 58 is a recording unit (recor
der).

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

Computer 10, VCR 28, and Printer 6
0 is the first to third 1394 interface 14,44,62
1394 serial bus nodes, and are connected to each other via the first to third 1394 interfaces 14, 44, 62, so that data transmission and reception, control by commands, and the like can be performed. .

In the present embodiment, for example,
Operates as a controller for transmitting and receiving image signals on the 1394 serial bus. Comput according to the present embodiment
In the er10, for example, a computer processing bus (MPU) 12 and an internal processing unit (MPU) 12, such as a 1394 interface 14, a keyboard 16, a decoder 18, a CRT display 20, a hard disk 22, an internal memory 24, etc. Each device is interconnected.

The arithmetic processing unit (MPU) 12 is a hard disk
Run the software recorded in 22 and
Various data is moved to the internal memory 24. The arithmetic processing unit (MPU) 12 also performs an arbitration operation of each device connected by the PCI bus 26 and the like.

The 1394 interface 14 receives an image signal transferred on the 1394 serial bus, and receives an image signal recorded on the hard disk 22 and an internal memory.
The image signal stored in 24 is transmitted.

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

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

The decoder 18 decodes an 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. Imaging optical system (opt) 30
The luminance signal (Y) and the color difference signal (C) of the video image input from the A / D converter 32 are converted into digital data. The digital data is supplied to a video processing unit (video process) 3
4 is multiplexed.

Thereafter, the data amount of the image information is compressed by a compression / expansion circuit (compression) 36. In general, the compression processing circuit is provided independently for YC. Here, for simplification of description, an example of compression processing in YC time division will be described.

Next, shuffling processing is performed to make the image data resistant to transmission path errors. The purpose of this processing 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, when emphasizing the purpose of equalizing the unevenness in the amount of information generated due to the unevenness in the image screen, if this processing step is brought before the compression processing, variable-length codes such as run-length This is convenient when using.

In response to this, data identification (ID) information for restoring data shuffling is added. The ID added by this ID adding operation is used as auxiliary information together with the system mode information and the like recorded at the same time in the decompression processing (information amount expansion processing) at the time of reproduction. Error correction (EC
C) Add information. Processing up to the addition of such a redundant signal is performed for each independent recording area corresponding to each information such as video and audio.

As described above, the image signal to which the ID information and the ECC information have been added is recorded on a recording medium such as a magnetic tape by the recording unit (recorder) 58, and a first memory (memory) described later. Stored temporarily at 38.

On the other hand, the image data multiplexed by the video processing section 34 is digital-to-analog converted by a D / A converter 56 and observed by an operator on an electronic viewfinder (EVF) 54.

The operator operates the second operation unit (operation) 5
2 through the system controller (s
ystem controller) 50
Numeral 50 controls the entire VCR 28 according to the operation information.

The image data multiplexed by the video processing unit 34 is output to a second memory 40 and is temporarily stored. The first memory 38 and the second memory 40 described above each include a first memory control circuit (memory
control) 46 and a second memory control circuit (memory control)
The operation of the system controller 50 is controlled by the system controller 50.

First data selector (data selector) 42
Selects the data from the first memory 38 and the second memory 40 described above and passes the data to the second 1394 interface 44, or selects the data from the second 1394 interface 44 To the first memory 38 or the second memory 40.

By the above operation, the second 13
From the interface 44, compressed image data and uncompressed image data can be selected and output by the operator.

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

The system controller 50 creates response data corresponding to the command data, and generates the first data selector 42 and the second 1394 interface.
The data is transmitted to the 1394 serial bus through 44.

In this embodiment, for example, the printer 60
Operates as an image printout device. The third 1394 interface 62 receives an image signal transferred on the 1394 serial bus and command data for controlling the printer 60 via the 1394 serial bus.

The third 1394 interface 62 is
The response data for the command is transmitted. The received image data is stored in a second data selector (data sele
ctor) 64 to a second decoder (decode) 70. The second decoder 70 decodes the image data and outputs it to an image processing unit (Image process) 74. The image processing unit 74 stores the decoded image data in a third memory (m
emory) Stored temporarily in 72.

On the other hand, the received command data is passed through the second data selector 64 to the printer controller (p
rinter controller) 68. The printer controller 68 sends a driver 76 based on the command data.
Paper feed control and printer head 78
Various printing controls such as position control of the printer are performed.

Further, the printer controller 68 converts the image data temporarily stored in the third memory 72 into
The print data is transmitted to the printer head 78 as print data, and the print operation is performed.

As described above, the first 1394 interface 14, the second 1394 interface 44, and the third 1394 interface 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, and the second 1394 interface 44 operates as a source node for image data. 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 (source), 20
4 is a destination node (destination), 206 is a subunit (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 a first connection (c
onnection # 0), 214 is the nth memory space of the destination, 216 is the nth connection (connection #n)
It is.

The controller 200 is a node that manages a connection ID for establishing a connection between the source node 202 and the destination node 204 that perform data transfer, and transmits and manages a query command.

The controller 200 includes a source node 202,
And the node independent of the destination node 204, or the source node or the destination node and the controller may be the same. In the latter case, it is the same node as the controller.

Note that no transaction is required between the source node or the destination node and the controller. In the present embodiment, the controller 200
Are the source node 202 and the destination node 20
Here is an example of the case where it exists in a different node from 4.

In the communication device according to the present embodiment, it is possible to establish a plurality of connections. The source node 202 transfers the object 208 such as image data from the internal subunit 206 to the first memory space inside the destination node through, for example, the first connection 212.
Write to 210. The transmission and reception of data by the above-described connection is performed using, for example, an asynchronous packet.

Next, the controller 200 and the source node 202 (source) described above with reference to FIG.
The operation of each node of the destination node (destination) 204 will be described.

The controller 200 transmits a data packet for making a connection to the source node and the destination node selected by the user. This packet is an asynchronous packet, and a connection ID for identifying this connection is written in the payload.

Following this packet, the controller 200
Transmits a transmission command packet to the source node 202. When receiving the transmission command packet, the source node
The destination node 204 and the destination node 204 perform a broadcast transaction using the assigned connection ID, and start data transfer.

When the data transfer is completed, the source becomes segment
The controller 200 sends a broadcast packet indicating the end, and upon receiving this packet, the controller 200
Is released, and the data transfer ends.

Here, the packet indicating the segment end is:
Since it is broadcast, the contents of the packet can be detected by the destination node. Therefore,
The destination node 204 itself is the source node 20
The connection with 2 may be released.

The source node 202, which has received the connection ID notification packet and the transmission command packet from the controller 200, transmits an asynchronous broadcast packet (inquiry to the destination node 204).
3 is transmitted. The connection ID specified by the controller is written in this packet.

The destination node 204 receives this packet and sends it out as a response broadcast packet (act response in FIG. 3). The same connection ID is also written in this packet, and the source node 202 checks this ID to determine whether the packet is addressed to this source node.

The buffer size and offset address of the destination node 204 are written in the response packet, and subsequent data transfer is performed by a write transaction for that address.

The source node 202 writes to the offset address received from the destination node 204 by using an asynchronous broadcast packet. This packet contains the connection ID
And the data sequence number.

After transmitting the broadcast packet,
The source node 202 waits for a response from the destination node 204. Destination node 20
From 4, a response packet in which the connection ID and sequence number are written is transmitted as an asynchronous broadcast packet. When this packet is received, the source node increments the sequence number and transmits the next data in the same manner.

The source node performs data transfer by repeating the above procedure, that is, the broadcast transaction (broadcast transaction # 1 to ## in FIG. 3).
n). In the present embodiment, the maximum time to wait for a response from the destination node 204 is predetermined, and if the response does not return after that time, the same sequence number is used.
Retransmit the same data.

When a response packet for a retransmission request is transmitted from destination node 204, data of the designated sequence number is retransmitted by broadcast. When the transfer of all data is completed, the source node transmits a broadcast packet indicating segment end, and ends the data transfer.

Also, in the present embodiment, the source node 202 divides all data to be transmitted into a predetermined amount (segment).
ation), and transmission is performed for each of the divided data. Here, the divided data is referred to as segment data. The above-described response is generated with the transmission and reception of the segment data. Transmission of each segment data is performed for each broadcast transaction.

In the present embodiment, the buffer size included in the above-mentioned response packet indicates the free space of the buffer provided in the destination node 204. In the present embodiment, the transmission of the response packet occurs once with the transmission of the segment data, but the present invention is not limited to this. For example, after the buffer of the destination node 204 is filled,
The destination node 204 may be configured to transmit the response packet.

The destination node, which has received the connection ID notification packet from the controller 200,
It waits for an asynchronous broadcast packet of a query from the source node 202.

Upon receiving the broadcast packet, the destination node 204 compares the connection ID written in the packet with the connection ID notified from the controller, and determines whether or not this packet is a packet from the source node. I do.

Upon receiving the inquiry packet from the source node 202, the destination node 204 broadcasts a response packet in which the connection ID, the buffer size for data reception, and the offset address are written.

Data from source node 202 is written to this address. When data is written from the source node 202, the destination node 204
Checks the connection ID in the payload.

This ID is notified from the controller 200.
If the ID matches, receive the data and connect
The response packet in which the 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 is transmitted, and the source node 202 can request data again.

When all data transfer is completed, a broadcast packet indicating segment end is transmitted from the source node 202. When this packet is received, the data transfer process ends.

By controlling the data transfer process in accordance with the above procedure, the communication system of the present embodiment can solve the inconvenience of the conventional communication system. Further, even in data transfer that does not require real-time properties, data can be easily and quickly transferred.

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

Next, the procedure of the retransmission request will be described with reference to FIG. When a bus reset occurs during data transfer, for example, when the sequence number of the broadcast transaction is i and the data transfer is interrupted, each node reconstructs the bus according to a procedure defined by the standard. .

After the rebuilding of the bus is completed, the destination node 204 determines the connection ID and the sequence number.
The resend request packet (resend request) with i
Send in broadcast packets.

When the data transfer can be resumed, the source node 202 returns an ack response. After that, the source node 202 checks the connection ID of the received packet, and after the requested sequence number, that is,
The data of the data sequence starting with the sequence number (i + 1) is sequentially transmitted in a broadcast packet.

According to the above-described procedure, the source node 202, the destination node 204, and the controller node can easily and reliably restart the subsequent data transfer even if the data transfer is interrupted, without considering the node ID. can do. Further, as described above, in the present embodiment, even when the data transfer is interrupted,
There is an effect that the control procedure of 200 can be simplified.

Next, referring to FIG. 4, the above-mentioned Asynchronous
The packet will be described. Asynch according to the present embodiment
The ronous packet 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, and this field indicates a node ID of a reception destination. As in the present embodiment,
When performing a broadcast, the value of this field is FFFF _16.

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

The next 4 bits field is a transaction code (tcode). tcode specifies the format of the packet and the type of transaction that must be performed. In the present embodiment, for example, this value is 0001 _2, using the transaction write request data block.

The next 4 bits field is a priority (pri) field, and specifies a priority. In this embodiment, because of the use of Asynchronous packets, the value of this field is 0000 _2.

The next 16 bits are a source ID field, and indicate a node ID on the transmission side. The next 48 bits are destin
The lower 48 bits of the destination node address of the packet is specified by this field.

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

The next 32 bits are a header CRC field, which is extended from the destination ID field described above.
The portion up to the tcode field is called a packet header, and is 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, bits less than the quadlet are filled with zeros. Next 32 bits
Is a data CRC field, and the head
Like the er CRC field, it is used for error detection of the data field.

FIG. 5 is a diagram in which fixed data is added to the above-mentioned fields in the asynchronous packet header used in the present embodiment. Also,
FIG. 6 is a diagram showing a structure of a data field of an Asynchronous packet used in the present embodiment.

In FIG. 6, data having the same functions as in FIG. 4 will not be described. The first two quadlets
This is header information, in which a connection ID or the like for identifying the connection described above is written.

The third and subsequent quadlets are variable-length data blocks. In this embodiment, if the data block is not a multiple of a quadlet, bits less than the quadlet are padded with zeros.

FIG. 7 is a diagram showing the structure of the header information. In FIG. 7, the first 16 bits
s is the above-mentioned connection ID (connection ID) field, and the connection is identified by the data. Here, the connection ID can establish 2 ¹⁶ × (the number of nodes) connections. Therefore, a plurality of connections can be set until the total amount of communication bandwidth used for each connection reaches the bus capacity.

The next 8 bits are the protocol type (protoco
l type) field, which indicates a procedure of data transfer using the header information. The procedure of exchanging this embodiment, for example, 01 ₁₆ values are used.

The next 8 bits are a control flag (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 the sequence number (sequence).
nce number) field. As described above, in the sequence number field, a continuous value is used for a data packet transmitted / received with a specific connection ID.

The destination node 204 monitors the continuity of significant data by using the sequence number field, and when a mismatch occurs, the source node 20
Request resend to 2.

The next 16 bits are a confirmation response number (reconfirm
ation number) field. This field is
This field is significant only when the value of the retransmission request flag is 1. When the value of the retransmission request flag is 1,
This field indicates the sequence number of the start packet for which a retransmission request has occurred.

(Second Embodiment) An outline of a data transfer operation will be described below as a second embodiment of the present invention with reference to FIG. In the first embodiment described above, a logical connection relationship between a source and a destination is indicated by using a connection ID, and one source and one destination are determined by using the connection ID and an asynchronous transaction by a broadcast method. The communication protocol for realizing communication with the destination has been described.

In this embodiment, the connection ID
And Asynchronous Streaming conforming to the IEEE1394-a standard
A communication protocol for realizing communication between one source and one or more destinations using packets will be described.

In the following embodiment, Asynchronous
Asynchronous Streaming T is a transfer method for communicating object data (for example, still image data of one screen or more, moving image data or audio data for a predetermined time, or text data for a predetermined number of images) using a streaming packet.
Called ransfer.

Here, the Asynchronous Streaming Transfer
r based communication is Async compliant with IEEE1394-1995 standard.
Executed within the transfer period of the hronous transfer method. Also, A
Communication based on synchronous Streaming Transfer is broadcast on a communication system,
This is a communication method suitable for communication between N devices.

Asynchronous Streaming Transfer
Communication based on the IEEE 1394-1995 standard
As in the communication based on the onous transfer method, it is necessary to set a predetermined channel number. Therefore, in the present embodiment, an Isochronous ResourceMas for managing a channel number used in communication based on the Isochronous transfer method.
nager (hereinafter referred to as IRM)
Processing for setting a channel number for communication based on hronous Streaming Transfer will be described.

Hereinafter, in the present embodiment, similarly to the first embodiment, for example, the communication protocol of this embodiment will be described with the computer 10 of FIG. 1 as a controller, the VCR 28 as a source, and the printer 60 as a destination. I do. Although FIG. 1 illustrates a communication system formed by three communication devices, the present invention is not limited to this. For example, a computer 10 VCR28, a communication system in which a plurality of each of the printers 60 may be connected,
The destination communication device is not limited to one.

In FIG. 2, reference numeral 200 denotes a controller;
Is the source node, 204 is the destination node, 20
6 is a subunit inside the source node, 208 is an object such as image data, 210 is a reception FIFO inside the destination node, 212 is a first connection, and 216 is an nth connection.

The controller 200 is a node for setting connection identification data for establishing a connection between the source node 202 for data transfer and the destination node 204.

The controller 200 includes a source node 202,
Also, the node may be independent of the destination node 204, or the source node or the destination node and the controller may be the same. In the latter case, no transaction between the controller and the source or destination node, which is the same node as the controller, is unnecessary. In the present embodiment, an example in which the controller 200 exists in a node different from the source node 202 and the destination node 204 will be described.

In the communication device according to the present embodiment, it is possible to establish a plurality of connections. The controller sets the same channel number and connection ID data to the destination node and the source node selected by the user using the asynchronous packet. The source node 202 transmits an Object 208 such as image data from the internal subunit 206 to the first connection 212, for example.
, Using the Asynchronous Streaming packet to write to the first memory space 210 inside the destination node.

Asynchronous Streami used at this time
The ng packet is transmitted using the channel number specified by the controller. The payload of this packet contains the connection ID set by the controller
Data is written as data header information.

The destination node determines the Asynchronous Strea of the channel number specified by the controller.
When the ming packet is received, the data is temporarily stored in the reception FIFO 210, and the data header in the data payload is analyzed. If the received packet is a data packet having a connection ID set by the controller, the data with the data header information removed is written to an internal buffer.

When a plurality of destination nodes exist, the connection can be identified using the channel number and the connection ID, so that data can be transferred to a plurality of nodes at the same time.

Next, an Asynchronous packet will be described with reference to FIG. Asynchronous according to the present embodiment
The packet is, for example, a data packet in units of 4 bytes (32 bits, hereinafter referred to as a quadlet). As
There are two types of asynchronous packets, a packet format for specifying a destination node ID and a packet format for specifying a channel number called Asynchronous Streaming.

The packet format shown in FIG.
This format specifies the node ID. As shown in FIG. 3A, the first 16 bits are a destination_ID field, and this field indicates a node ID of a destination. 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 (r
t) A code that specifies whether the packet attempts to 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 (binary number) is used. The next 4bits field is the priority (pri) field,
Specify the priority. In the present embodiment, Asynch
Since ronous packets are used, the value of this field is 0000 (binary).

The next 16 bits are a source_ID field, which indicates a node ID of the transmitting side. The next 48 bits are destinat
It is an ion_offset field, and the lower 48 bits of the destination node address of the packet are specified by this field.

[0171] The next 16 bits are a data_length field, which indicates the length of a data field described later in bytes. The next 16 bits are an extended_tcode field, and in a data block write request transaction used in the present embodiment, this value is 0000 (hexadecimal).

The next 32 bits are a header_CRC field, and extend from the destination_ID field described above.
Up to the ed_tcode field is called a packet header,
Used for error detection of the header packet.

The next field is a variable-length data field, and this data field is called the payload of the packet. In the present embodiment, if the data field is not a multiple of a quadlet, bits less than the quadlet are padded with zeros.

The next 32 bits field is a data_CRC field, and is used for error detection in the data field, similarly to the header_CRC field. The packet format shown in FIG. 3B is an asynchronous streaming format that specifies a channel number.

As shown in FIG. 3B, the first 16 bits are
The data_length field indicates the length of a data field described later in bytes. Next 2 bits
Is the tag field, whose value is 00 (binary). The next 6 bits are a channel field, and represent a channel number of this packet. The receiving node identifies the packet using this channel number.

[0176] The next 4 bits are the transaction code (t
code). In the Asynchronous streaming packet,
A (hexadecimal). The next 4 bits are Synchronization
code (sy) field, the value of which is determined by the application using this packet.

The next 32 bits are a header_CRC field, and a portion from the data_length field to the sy field is referred to as a packet header, and is used for error detection of the header packet.

The next field is a variable-length data field, and this data field is called the payload of the packet. In the present embodiment, if the data field is not a multiple of a quadlet, bits less than the quadlet are padded with zeros. The next 32 bits field is the data_CRC field,
Like the ader_CRC field, it is used for error detection in the data field.

Next, referring to FIGS. 11 and 12, the controller 200, the source node 202, the destination node 204 and the IRM (Is (Is
o performed between ochronous Resource Manager nodes)
The synchronous transaction will be described. In addition,
In the following description, FIG. 11 illustrates a case where a connection is set between one source node and one destination node, and FIG. 12 illustrates a case where a connection is established between one source node and a plurality of destination nodes. The case where the setting is performed will be described.

The controller is the CHANNE of the IRM node.
A Read Request packet for the LS_AVAILABLE register is issued, and the IRM that has received the packet issues a CHANNELS_
Send the data of the AVAILABLE register to the controller as Read Response. The status of use of each channel at that time is set in this register, and an unused channel can be known by checking this data. The controller selects one channel from unused channels.

Next, the controller issues a connection set command to the source node. The channel number selected by the controller and the connection ID managed by the controller are written in this setup command. The source node that has received the setup command transmits a response packet of the setup command to the controller.

The source node notified of the channel number from the controller is the CHANNELS_AVAI of the IRM node.
The IRM that issues a Read Request packet for the LABLE register and receives the packet is CHANNELS_AVAILA
Send the data of the BLE register to the source node as a Read Response.

The source node uses this response data to send a Compare & Swap Lock Request packet to the IRM.
Send to This Lock packet is a packet for rewriting the bit corresponding to the channel number notified from the controller. When the Lock transaction is successful, the channel is secured. IRM is Lock Request
To the source node.

The controller, following the source node,
Send a connection setup command to the destination node. In this setup command, the same data as the channel number and connection ID notified to the source node described above are written. The destination node transmits a response packet to the setup command.

As shown in FIG. 12, when there are a plurality of destination nodes, the above-mentioned setup command is sequentially transmitted to each destination to perform the setup.

By the above procedure, a common Asynchronous Stream channel and a common connection ID are set between the source node and the destination node, and a logical connection is established.

Next, the controller transmits a data reception command to the destination. The destination receiving this command prepares for data reception and transmits a response packet to the controller. As shown in FIG. 12, when there are a plurality of destinations, a data reception command is sequentially transmitted to each destination, and each destination enters a reception standby state.

After setting the destination in the reception standby state, the controller transmits a data transmission command to the source node. The source node receiving this command sends a response packet to the controller. The above transaction is performed by using Read and Write using an Asynchronous packet in the format of FIG.
e, Locked by transaction.

FIG. 13 shows an example of the format of a command packet used for the above-described setup command, data reception command, and data transmission command. The data in the format shown here is set in the data field of FIG. 10A as the payload of the Asynchronous packet, and transmitted to the destination node using a Write transaction. The ctype field indicates the type of command, and specifies the command type shown in Table 1.

[0190]

[Table 1]

In the case of each of the above-mentioned commands, Control is designated. The subunit_type and subunit ID fields are fields indicating which unit in the specified node the command is for. The opcode and operand fields are fields for specifying the contents of the actual command.

FIG. 14 shows a format example of a response packet for each of the above commands. The data in the format shown here is stored in the data field of FIG.
It is set as the payload of the Asynchronous packet and transmitted to the controller node. The response field indicates the type of response, and specifies the response type shown in Table 2.

[0193]

[Table 2]

The subunit_type and subunit ID fields are fields indicating from which unit in the node the response is. The opcode and operand fields are fields for specifying response data. When the node that has received each command from the controller receives the command, it transmits a response packet in which the response field is set to Accepted to the controller using a Write transaction.

The source node that has received the data transmission command divides the previously selected object data into a plurality of segments, and sequentially transmits each segment data. This segment data is stored in Asyn in FIG. 10 (b).
Sent using a chronous Streaming packet. At this time, the channel number secured from the IRM is set in the channel field shown in FIG.

Next, the procedure for dividing and transmitting object data will be described with reference to FIG. At the source node, an object having an image size of 128 KB is selected, and this data is transmitted to the destination.
At the source node, the object data is
Divided into 512 segments of bytes, and each segment is Asyunchronous Streaming Transfer using a predetermined channel
To send to the destination.

At the destination, an Asynchronous Streaming packet of a predetermined channel is fetched into the reception FIFO, and the data payload is checked. Receive image data from a source node.

FIG. 15 shows a format example of the divided object data set in the data field of FIG. 10B. One quadlet at the head of the data is a header field (hereinafter, Stream Info Header
Shown). The control_flags field indicates the type of data transmitted in this packet. Table 3 shows an example of control_flags of a transmission packet.

In FIG. 16, the packet for transmitting the data of Segment 0 to Segment 510 includes “Normal segment data”.
Is set, and the final data of the object is Seg
In the ment 511, “Segment data of object end” is set.

[0200]

[Table 3]

[0201] In the connection_id field, a connection ID set by the controller is set.
In the segmented object data field, divided object data is set.

In the case of the example shown in FIG.
o Total of 4 bytes of Header and 256 bytes of segment data
260 bytes are transmitted from the source node using the channel number as the payload of the Asynchronous Streaming packet.

The destination node is Asynchrono
When a us Streaming packet is received, the packet header
Check the channe1 field, and if the packet has the channel number notified from the controller, fetch the packet into the receive FIFO.

Further, the stream of the fetched packet
Check whether the connection_id field of the Info Header is the connection ID notified by the controller, and if they match, check the Stream Info Head from the payload.
Write the segment data excluding the 4 bytes of er to the internal buffer. Also, control_flag of stream Info Header
Examine s to determine if it is the final data of the object.

In the case of FIG. 16, the data reception starts and the stream of the 512th asynchronous streaming packet is started.
"Segment data of" is added to control_flags of Info Header.
object end "is set, and the transfer of object data ends when segment data is written from the data packet to the internal buffer.

Next, referring to FIG. 17, Data Transfer when there are a plurality of destinations shown in FIG.
The flow will be described. As shown in FIG. 15, each segment data shown in FIG.
It is set in the payload of the ronous Streaming packet and transmitted from the source node on a predetermined channel.

At this time, co of the header information in the payload is
The connection ID notified from the controller is set in the nnection_id field, and the value shown in the flow of FIG. 17 is set in the control_flags field. When transmitting the data of the segment 511, which is the final data, control_fl
In the ags field, 01h indicating “Segment data of object end” is set.

Each destination node transmits the Asynchronous Stream of the channel notified from the controller.
The ng packet is received, the contents of the header information in the payload are confirmed, data is extracted from the packet of the connection ID set in the ng packet, and the data is sequentially copied to the internal buffer.

[0209] Asynchronous S whose control_flags is 01h
Upon receiving the treaming packet, each destination detects that the reception of the object data has been completed, and ends the receiving operation. Each segment packet shown in FIG. 17 is transmitted only once from the source node, and a plurality of destination nodes that have been set up with a logical connection with the source node can simultaneously receive the packet.

When there is only one destination node, there is only one destination in FIG. 17, and the flow of Data Transfer is the same as when there are a plurality of destination nodes.

As described above, the controller sets the same channel number and connection ID to the destination node and the source node, so that a logical connection can be set between the source node and the destination node. Processing can be performed in a transaction only between the source and destination, without the intervention of the controller.

Also, by notifying the same channel number and connection ID to one source node and a plurality of destination nodes, a 1: N logical connection can be set. 1 to N data communication can be performed using the above procedure.

Further, even when there are a plurality of destination nodes, there is no need to individually transmit data to each destination node, and traffic on the bus can be reduced.

(Third Embodiment) A third embodiment described below.
In the embodiment, Asynchronous Streaming Transfer
5 illustrates a system for reliably transferring object data to a destination using the. Since the procedure for the controller to set the logical connection between the source node and the destination node is the procedure shown in FIGS. 11 and 12 as in the second embodiment, the detailed description is omitted.

In this embodiment, as in the second embodiment, a case will be described in which the object data shown in FIG. 16 is transferred from the source node to the destination node.

FIG. 18 shows an example of Asynchronous S in this embodiment.
4 shows a format example of an application header added to the payload of a treaming packet. In the following description, this header is referred to as Common Asynchronous Streaming He
ader and CAP header. This header is variable-length data in units of one quadlet (32 bits).

In FIG. 18, EOH_n (End of CAP hea)
der) indicates whether this is the last quadlet of the CAP header, 0 for this quadlet followed by another quadlet data, 1 for this quadlet ends the header.

Form_n is a combination of EOH and CHF
_N. CHF_n (CAP header field) is n
This is the CAP header field for the quadlet. The structure of this field depends on the value of EOH and Form.

In the present embodiment, as shown in FIG.
A CAP header of one quadlet is added to the beginning of the payload of the asynchronous streaming packet, and the segment-divided data is transmitted. In this example, EOH — 0 = 1, Form
_0 = 0.

Control flags field and connection
The _id field is the same as in the second embodiment. Se
The quence Number field is a serial number of the segment data transmitted in this packet. Se shown in FIG.
When sending gment, 0 for Segment 0, Se
For gment 1, 1 is set in the Sequence Number field. The segmented object data field is set with the segmented object data.

In the present embodiment, Data T shown in FIG.
The detailed flow of ransfer is shown in FIG. Each shown in FIG.
The segment data is set in the payload of the Asynchronous Streaming packet together with the CAP header as shown in FIG. 19, and transmitted from the source node on a predetermined channel. At this time, the connection_id field of the CAP header contains the connection ID notified from the controller.
However, the values shown in the flow of FIG. 21 are set in the control_flags field and the Sequence Number field. When transmitting the data of Segment511 which is the last data, cont
The rol_flags field is “Segment data of object e
01h indicating nd "is set.

[0222] The destination node transmits the Asynchronous Streaming of the channel notified from the controller.
It receives the packet, checks the contents of the CAP header, extracts data from the packet with the connection ID set for itself, and sequentially copies it to the internal buffer. control
When the Asynchronous Streaming packet whose _flags is 01h is received, the destination sends a Response packet indicating that the reception of the object data has been completed to Asynchro.
Send using nous Streaming Transfer. FIG. 20 shows an example of the format of this packet.

The data shown in FIG. 20 is in the CAP header format.
nous Set as the payload of the Streaming packet and transmitted. The channel at this time is the same as the channel used by the source node for transmitting the object, and the connection_id in the CAP header is also the same as the connection ID used by the source node for transmitting the object.

The control_flags field is data indicating the type of response, and Table 4 shows an example thereof. Indicates "Receive success" if data was successfully received 10
h is set. If reception is successful, Sequence N
In the umber field, Sequence N of the last data received
Set umber.

[0225]

[Table 4]

When the source node transmits the final data of the object data, the source node waits for a response, and waits for a response from the destination to be transmitted. When an Asynchronous Streaming packet of the same channel as the channel used for data transmission is received,
Check the CAP header in the packet, confirm that the packet was received normally, and end the transfer of the object data.

Next, FIG. 22 shows a flow when an error occurs during data transmission. As in the example shown in FIG. 21, the source node starts transmitting data. Se
If the destination node cannot receive the data of gment n due to some failure, the destination node will receive the data of Segment n + 1 at the destination node.
Detects missing data of gment n. At this point, the destination node sends a response packet requesting the source node to retransmit data asynchronously.
Send using us Streaming Transfer.

The format of this packet is the same as that of the Response packet transmitted when the object data can be normally received, and is transmitted using the channel and connection ID used by the source node for transmitting the object. The control_flags field in the CAP header is set to 11h indicating "Reasend request", and the Sequence Number field is set to the Sequence Number of data that could not be received.

The source node is an Asynchronous Streami of the same channel as the channel used for data transmission.
When an ng packet is received, the CAP header in the packet is checked, and if it is a Response of “Resend request”, the segment corresponding to the specified Sequence Number is confirmed.
Start retransmission from data. The subsequent data transfer flow is the same as when the object is normally transferred.

Next, FIG. 23 shows a flow when a bus reset occurs during data transfer. As in the example shown in FIG. 21, the source node starts transmitting data. Se
When a bus reset occurs after transmitting data of gment n, each node on the bus reconstructs the bus in a predetermined procedure.

When the bus reconstruction is completed, the source node and the destination node resume the transfer of the object data using the channel and the connection ID set by the controller before the bus reset, as in the case before the bus reset. At this time, the source sword resumes data transmission from the segment data next to the segment data transmitted before the bus reset.

[0231] The destination node receives the data received after the bus reset from the Se which could be received before the bus reset.
If it is the next data after the gment data, the reception continues as it is.
If the segment data has not been received, a retransmission request packet for the segment n is transmitted as in the case of the above-described float at the time of error, and the source starts data retransmission again from the data of the segment n. The subsequent data transfer flow is the same as when the object is normally transferred.

As described above, by providing a header in the payload and adding the information of the Segment data,
Reliable data communication can be performed using the asynchronous streaming transfer, and data can be retransmitted even when received data is lost due to an error or a bus reset.

(Other Embodiments of the Present Invention) The present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but also to an apparatus composed of one device. You may.

In order to realize the functions of the above-described embodiments, a device connected to the above-described various devices or a computer in a system is operated so as to operate various devices so as to realize the functions of the above-described embodiments. The present invention also includes a program that is implemented by supplying the program code of the software described above and operating the various devices according to a program stored in a computer (CPU or MPU) of the system or apparatus.

Further, in this case, the program code of the software implements the functions of the above-described embodiment, and the program code itself and means for supplying the program code to a computer are provided.
For example, a storage medium storing such a program code constitutes the present invention. As a storage medium for storing such a program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM,
A magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the supplied program code, not only the functions of the above-described embodiment are realized, but also the OS (operating system) or other operating system running on the computer. Needless to say, the program code is also included in the embodiment of the present invention when the functions of the above-described embodiment are realized in cooperation with application software or the like.

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 function expansion board or the function expansion unit is stored based on the instruction of the program code. It is needless to say that the present invention also includes a case where a CPU or the like provided in the first embodiment performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0239]

As described above, the present invention has the effect of solving the inconvenience of the conventional communication system. In addition, even in data transfer that does not require real-time processing, there is an effect that data can be transferred easily and at high speed. According to the present invention,
When the communication band is not used much, there is an effect that a large number of communications can be performed simultaneously. Further, according to the present invention, it is possible to easily detect data lost due to interruption of data transfer, and to reliably and easily return from interruption of data transfer. There is.

According to another feature of the present invention, since a logical connection uniquely determined by a combination of a channel number and connection ID data can be set, data is transmitted in a single segment packet to a plurality of destinations. It has the effect of reducing traffic on the bus.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of the present invention.

FIG. 2 is a block diagram showing the operation of each node according to the present invention.

FIG. 3 is a diagram showing a diagram illustrating transmission and reception of commands and data between nodes according to the present invention.

FIG. 4 is a diagram showing an asynchronous packet according to the present invention.

FIG. 5 shows an Asynchronous used in the embodiment of the present invention.
It is a figure showing a packet.

FIG. 6 shows an Asynchronous used in the embodiment of the present invention.
FIG. 3 is a diagram illustrating a structure of a data field of a packet.

FIG. 7 is a diagram showing a structure of a header in a data field used in the embodiment of the present invention.

FIG. 8 is a diagram showing an example of the related art.

FIG. 9 is a diagram for explaining an outline of a data transfer operation according to the present invention.

FIG. 10 is a diagram showing a packet used for an asynchronous transaction.

FIG. 11 is a diagram showing a diagram illustrating transmission and reception of commands and data between nodes according to the embodiment of the present invention.

FIG. 12 is a diagram illustrating transmission and reception of commands and data between nodes when a plurality of destinations exist according to the embodiment of the present invention.

FIG. 13 is a diagram showing an example of a data format used for a command packet according to the present invention.

FIG. 14 is a diagram showing an example of a data format used for a response packet to a command packet according to the present invention.

FIG. 15 is a diagram illustrating an example of a format of a payload of an Asynchronous Streaming packet transmitted from a source node according to the first embodiment of this invention.

FIG. 16 is a diagram for describing an example of transferring object data according to the embodiment of this invention.

FIG. 17 is a diagram showing a flow of object data transfer in the embodiment of the present invention.

FIG. 18 shows an embodiment of Asynchronous S in the embodiment of the present invention.
It is a figure showing an example of the format of the header data added to the payload of the treaming packet.

FIG. 19 is a diagram showing an example of a payload format of an Asynchronous Streaming packet transmitted from a source node in the embodiment of the present invention.

FIG. 20 is a diagram illustrating an example of a payload format of an Asynchronous Streaming packet transmitted from a destination node according to the embodiment of the present invention.

FIG. 21 is a diagram showing a flow of object data transfer in the embodiment of the present invention.

FIG. 22 is a diagram showing a flow when an error occurs during transfer of object data according to the embodiment of the present invention.

FIG. 23 is a diagram showing a flow when a Bus Reset occurs during the transfer of object data according to the embodiment of the present invention.

FIG. 24 is a diagram for explaining conventional one-to-N communication.

FIG. 25 is a diagram illustrating a method of transferring an object.

FIG. 26 is a diagram showing a flow of a conventional one-to-N object transfer.

[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 device such as CRT display 22 Hard disk 24 First memory 26 Internal bus of computer such as PCI bus 28 VCR 30 Imaging optical system 32 A / D converter 34 Video processing unit 36 Compression / expansion 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 operation unit 54 Electronic viewfinder 56 D / A converter 58 Recording unit 60 Printer 62 Third 1394 interface 64 Second data selector 66 Third operation unit 68 Printer Controller 70 Second decoder 72 Third memory 74 Image processing unit 76 Driver 78 Printer head 200 Control node 202 Source node 204 Destination node 206 Subunit inside source node 208 Object such as image data 210 First memory space inside destination node 212 First connection 214 nth memory space inside destination node 216 nth connection

Continuation of front page (72) Inventor Mitsuo Niida Canon Inc. 3- 30-2 Shimomaruko, Ota-ku, Tokyo

Claims (50)

[Claims] In a data communication system composed of a plurality of devices, a connection ID indicating a logical connection is used between a transmitting device for transmitting information data and a receiving device for receiving the information data. A data communication system for connecting and communicating. 2. The data communication system according to claim 1, wherein the data communication system includes a management device having a function of managing the connection ID, and uses the management device to perform a logical operation between the plurality of devices. A data communication system characterized by setting a dynamic connection. 3. The data communication system according to claim 2, wherein the management device uses the node IDs of a plurality of devices included in the data communication system to connect the transmission device and the reception device to the connection device. A data communication system for transmitting an ID. 4. The data communication system according to claim 2, wherein the management device is an Asyn compliant with the IEEE 1394 standard.
A data communication system for transmitting the connection ID using a chronous transfer method. 5. The data communication system according to claim 2, wherein communication between the transmitting device and the receiving device is performed using the connection ID. Data communication system. 6. The data communication system according to claim 1, wherein information data output from the transmitting device is transferred to all devices constituting the data communication system. Characteristic data communication system. 7. The data communication system according to claim 6, wherein the information data output from the transmitting device is IEEE1
A data communication system wherein data is transferred using an asynchronous transfer method conforming to the 394 standard. 8. The data communication system according to claim 1, wherein the transmitting device transmits a communication packet configured by a broadcast ID designating all devices constituting the data communication system and the connection ID. And transmitting the information data using the data communication system. 9. The data communication system according to claim 2, wherein the management device is arranged between a pair of a transmission device and a reception device.
A data communication system, wherein a plurality of connection IDs can be set. 10. The data communication system according to claim 2, wherein the management device is configured to be able to set a plurality of connection IDs between one transmission device and a plurality of reception devices. Data communication system. 11. The data communication system according to claim 2, wherein the management device is configured to be able to set a plurality of connection IDs between a plurality of transmission devices and one reception device. Data communication system. 12. The data communication system according to claim 2, wherein the management device is configured to be able to set a plurality of connection IDs between a plurality of transmission devices and a plurality of reception devices. Data communication system. 13. The data communication system according to claim 2, wherein the management device manages additional information on the plurality of connection IDs using a table. 14. The data communication system according to claim 2, wherein the management device recognizes that the communication of the information data has ended based on an end flag transmitted from the transmission device. A data communication system, comprising: 15. The data communication system according to claim 2, wherein the logical connection between the transmitting device and the receiving device is released by the management device or the receiving device. A data communication system, comprising: 16. The data communication system according to claim 1, wherein the receiving device responds to the connection request of the transmitting device by receiving a buffer size and an offset address in a predetermined memory space. A data communication system for returning a packet including a sequential number indicating a data start pointer and information indicating preparation completion. 17. The data communication system according to claim 1, wherein the receiving device is provided with a bit indicating that data has been received normally. 18. The data communication system according to claim 1, wherein the transmitting device measures a response from the receiving device for a predetermined period, and detects a communication abnormality based on the period. Characteristic data communication system. 19. The data communication system according to claim 18, wherein the transmitting device automatically starts a retransmission operation of the information data when detecting the communication abnormality. . 20. The data communication system according to claim 1, wherein an amount of data that can be transmitted by the transmitting device at one time is equal to or less than a capacity of a communication buffer included in the receiving device. Characteristic data communication system. 21. The data communication system according to claim 20, wherein each time the receiving device receives data transmitted by the transmitting device, the receiving device sends a response signal indicating completion of reception preparation to the transmitting device. A data communication system characterized by transmitting data. 22. The data communication system according to claim 20, wherein the receiving device, after the communication buffer is filled,
A data communication system, wherein a response signal indicating that preparation for reception is completed is transmitted to the transmitting device. 23. The data communication system according to claim 20, wherein the transmitting device transmits data to the receiving device at least during a period until a response signal is received from the receiving device. A data communication system which waits for transmission. 24. In a data communication system constituted by a plurality of devices, a broadcast ID designating all of the plurality of devices constituting the data communication system to perform communication performed asynchronously between logically connected devices. A data communication system, wherein the data communication is performed by using the data communication system. 25. The data communication system according to claim 24, wherein the communication performed asynchronously with respect to the predetermined communication cycle is an asynchronous transfer system based on the IEEE 1394 standard. 26. A data communication system including a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing the communication of the information data, comprising: an initial setting in the communication of the information data; Using the transmitting device, the receiving device, and the management device, and performing communication of the information data that is started after the initial setting using the transmitting device and the receiving device. system. 27. A data communication system including a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing communication of the information data, wherein the transmitting device and the receiving device The management device includes a connection I indicating a logical connection of the communication of the information data.
D, wherein the transmitting device and the receiving device perform communication of the information data using the connection ID. 28. A data communication system including a transmitting device for transmitting information data and a receiving device for receiving the information data, wherein the receiving device has a predetermined memory provided in the receiving device for the transmitting device. A data communication system for transmitting the information data together with data designating the predetermined memory space. 29. A data communication device connectable to a communication system constituted by a plurality of devices, comprising: a logical connection for communication between a transmitting device transmitting information data and a receiving device receiving the information data. A data communication device comprising: storage means for storing a connection ID indicating the following; and transmission means for transmitting the information data using the connection ID stored in the storage means. 30. A data communication device connectable to a communication system constituted by a plurality of devices, comprising: a logical connection for communication between a transmitting device for transmitting information data and a receiving device for receiving the information data. A data communication apparatus comprising: a storage unit for storing a connection ID indicating the connection ID; and a reception unit for receiving information data output on the communication system using the connection ID stored in the storage unit. . 31. A data communication method applicable to a data communication system including a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing communication of the information data, Initial setting in communication of information data is performed using the transmitting device, the receiving device, and the management device, and the communication of the information data started after the initial setting is performed by the transmitting device and the receiving device. A data communication method characterized in that the data communication method is performed by using the data communication method. 32. A data communication method applicable to a data communication system including a transmitting device for transmitting information data, a receiving device for receiving the information data, and a management device for managing communication of the information data, The transmission device, the reception device, and the management device are connected by a connection I indicating a logical connection of the communication of the information data.
A data communication method, wherein D is set, and the transmitting device and the receiving device communicate the information data using the connection ID. 33. A data communication method applicable to a data communication system including a transmitting device for transmitting information data and a receiving device for receiving the information data, wherein a predetermined value included in the receiving device with respect to the transmitting device is provided. And transmitting the information data together with the data specified in the predetermined memory space. 34. A data communication method applicable to a data system constituted by a plurality of devices, wherein communication performed asynchronously between logically connected devices is performed by a plurality of devices constituting the data communication system. A data communication method characterized in that the data communication method is performed using a broadcast ID that designates all of them. 35. A storage medium storing a program for causing a computer to execute the procedure of the data communication method according to claim 31. 36. A data communication system including a transmitting device for transmitting information data and one or more receiving devices for receiving the information data, wherein the transmitting device and the one or more receiving devices are on a transmission path. Performing communication of the information data using channel ID information indicating a predetermined channel assigned to the communication device and connection ID information indicating a logical connection between the transmitting device and the one or more receiving devices. A data communication system, comprising: 37. The data communication system according to claim 36, wherein the transmitting device packetizes the information data into one or more communication packets and sequentially transmits the communication packets. system. 38. The data communication system according to claim 37, wherein the channel ID information is stored in a header part of the communication packet, and the connection ID information is stored in a data part of the communication packet. Characteristic data communication system. 39. The data communication system according to claim 37, wherein the transmission device stores number information indicating an order of the communication packet in each of the communication packets. 40. The data communication system according to claim 36, wherein the channel ID information and the connection ID information are set by a management device that manages communication of the information data. A data communication system, comprising: 41. The data communication system according to claim 36, wherein the transmitting device sets the channel ID information and the connection ID information based on a predetermined communication protocol. Characteristic data communication system. 42. The data communication system according to claim 36, wherein the transmission device performs retransmission processing of the information data according to a change in a connection configuration of the data communication system. A data communication system, comprising: 43. The data communication system according to claim 36, wherein the receiving device receives the information data transmitted using predetermined channel ID information and includes the information data in the information data. And storing the information data in an internal buffer based on the connection ID information. 44. The data communication system according to claim 36, wherein the channel ID information conforms to an IEEE1394-1995 standard.
A data communication system managed by an Isochronous ResourceManager. 45. The data communication system according to any one of claims 36 to 44, wherein the information data is broadcast on the data communication system. 46. The data communication system according to any one of claims 36 to 45, wherein the information data is an Asynch compliant with the IEEE1394.a standard.
A data communication system characterized by being packetized in a ronous Streaming packet format. 47. A data communication device used for a data communication system including a transmitting device for transmitting information data and one or more receiving devices for receiving the information data, the data communication device indicating a predetermined channel allocated on a transmission path. Setting means for setting channel ID information and connection ID information indicating a logical connection between the transmitting device and the one or more receiving devices; andthe channel ID information set by the setting device and the A data communication device for communicating the information data using connection ID information. 48. In a data communication system including a transmitting device for transmitting information data and one or more receiving devices for receiving the information data, channel ID information indicating a predetermined channel allocated on a transmission path; A data communication method, wherein the information data is communicated using connection ID information indicating a logical connection between the transmitting device and the one or more receiving devices. 49. A storage medium storing a program for causing a computer to function as each of the means according to claim 36. 50. A storage medium storing a program for causing a computer to execute the procedure of the data communication method according to claim 48.