JP2004064665A - Data transfer device, transmitting device, receiving device, and method for controlling them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data transfer device by which flow control is easily performed, and data is easily divided and re-constituted. <P>SOLUTION: When connection is requested from a transmitting device to a receiving device (2801), the receiving device gives the address and the size of a writable data window in response (2802). The transmitting device writes data in the data window in response to the report (2803, 2804). The receiving device further secures a memory space, and reports it to the transmitting device by a window report 2806. The transmitting device writes data till transmission is completed in response to the data window reported from the receiving device. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data transfer device and method for performing data transfer by connecting via a memory map bus or the like. In particular, the present invention relates to a data transfer device, a transmission device, a reception device, and a control method thereof which are connected via an IEEE 1394 bus and perform data transfer.
[0002]
[Prior art]
Conventionally, as a transfer method using a memory map bus, particularly an IEEE 1394 bus, there have been a thin protocol, an AV / C asynchronous connection, an SBP2, and the like. In the thin protocol, the address and size of the data transfer window are fixed by negotiation. The address size of the segment buffer (Segment Buffer) of the AV / C asynchronous connection is also fixed in advance. In SBP2, the data area and the like are variable because they can be specified by the ORB, but the area is not dynamically changed before the area transfer is completed. Note that the memory map bus is an architecture in which data can be written to and read from a mapped memory space.
[0003]
[Problems to be solved by the invention]
In a case where a continuous block of data, such as a file, on a transmitting device is to be easily transferred to a receiving device, the above-described conventional example has the following problems. In the thin protocol, the address and size of the data transfer window (segment register) are fixed by negotiation, and if the size of the data to be transferred exceeds this size, it is necessary to divide the data into segments. You need to add a header. The address of the segment buffer of the AV / C asynchronous connection is also fixed in advance, and the transmitting device cannot start transferring the next data until the receiving device processes all the data in the segment buffer. In SBP2, the area is variable in the ORB, but the address of that area does not slide dynamically before the transfer of the area specified by the ORB is completed. Requires memory resources.
[0004]
As described above, when transferring a large amount of data, any of the transfer methods causes a problem such as an overhead for a transfer process or a need for a large amount of memory resources.
[0005]
The present invention has been made in view of the above conventional example, and has as its object to provide a data transfer device, a transmission device, a reception device, and a control method thereof, in which flow control is simple and data division and reconstruction are easy.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
[0007]
A data transfer system having a first device and a second device connected by a memory map bus,
The first device comprises:
Arranging means for arranging a data area variably in address and size in a node address space of the memory map bus;
Notifying means for notifying the second device of the address and size information of the area arranged by the arranging means,
The second device performs data transfer with the first device via the data area in the first device based on the address and size information notified by the notifying unit.
[0008]
More preferably, the first device arranges a writable data area by the arrangement means, and notifies the address and size information to the second device by the notifying means, wherein the second device The data is transferred from the second device to the first device by writing data to the data area via the memory map bus based on the address and size information notified by the notification means.
[0009]
More preferably, the second device divides the data so that its address corresponds to the address of the node address space and writes the data into the data area, and the first device writes the data into the data area. The data is reconfigured so that its address corresponds to the address in the node address space.
[0010]
More preferably, the first device writes data in the data area, and notifies the second device of the address and size information by the notifying unit, and the second device transmits the address and size information by the notifying unit. The data is transferred from the first device to the second device by reading data from the data area via the memory map bus based on the notified address and size information.
[0011]
More preferably, the first device divides the data so that its address corresponds to the address of the node address space and writes the data into the data area, and the second device writes the data into the data area. The data is reconfigured so that its address corresponds to the address in the node address space.
[0012]
More preferably, the first device further includes a release unit for releasing the data area allocated by the allocation unit, and the data area is set in the node address space by repeating the allocation by the allocation unit and the release by the release unit. Move within.
[0013]
More preferably, the memory map bus is an IEEE 1394 bus, and the notification by the notification unit and the data transfer are performed by a transaction provided by a transaction layer of an IEEE 1394 interface.
[0014]
Alternatively, a receiving device connected to the transmitting device by a memory map bus,
Arranging means for arranging a writable area by the transmitting device variably in address and size in a node address space of a memory map bus;
Notifying means for notifying the transmitting device of the address and size information of the area,
Receiving means for receiving data written in the area by the transmitting device.
[0015]
Alternatively, a transmitting device connected to the receiving device by a memory map bus,
Receiving means for receiving address and size information from the receiving device;
Transmitting means for transmitting data by writing data in an area specified by the address and size information received by the receiving means.
[0016]
Alternatively, a transmitting device connected to the receiving device by a memory map bus,
Means for arranging a writable area by the transmitting device variably in address and size in a node address space of a memory map bus, and writing transmission data in the area;
Notifying means for notifying the receiving device of the address and size information of the area,
Transmission means for transmitting data written by the transmission device to the area.
[0017]
Alternatively, a receiving device connected to the transmitting device by a memory map bus,
First receiving means for receiving address and size information from the transmitting device;
Second receiving means for receiving data by reading data from an area specified by the address and size information received by the receiving means.
[0018]
With this configuration, the flow control is simplified by notifying the area for data transfer on the node address space of the memory map bus, and the transmission data is made to correspond one-to-one with the address of the transfer data and the address of the node address space. It is possible to provide a simple data transfer device by facilitating data division at the time and data reconstruction after reception.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
(First Embodiment)
As a first embodiment of the present invention, a data transfer system in which a transmitting device and a receiving device are connected by an IEEE 1394 bus will be described. FIG. 1 is a block diagram showing the present embodiment. In the figure, 1 is a transmitting device, 2 is a receiving device, and 3 is an IEEE1394 cable. The transmission device 1 includes a CPU 12, a ROM 13, a RAM 14, an external device 15, and an IEEE 1394 interface 16 connected to each other via a system bus 11. The CPU 12 uses the RAM 13 as a work area based on a program stored in the ROM 13. The file stored in the external device 15 as a storage device is transmitted to the receiving device via the IEEE 1394 interface 16. The receiving device 2 includes a CPU 22, a ROM 23, a RAM 24, an external device 25, and an IEEE 1394 interface 26 connected to each other via a system bus 21, and the CPU 22 uses the RAM 23 as a work area based on a program stored in the ROM 23. The file received from the transmitting device via the IEEE1394 interface 26 is stored in the external device 25 which is a storage device. The IEEE 1394 interface 16 of the transmitting device and the IEEE 1394 interface 26 of the receiving device are connected to each other via an IEEE 1394 cable 3.
[0020]
Here, the outline of the IEEE 1394 technology used in the present embodiment will be described.
[0021]
<Overview of IEEE 1394 Technology>
Hereinafter, the technology of the IEEE 1394-1995 standard applied to the digital interface of the present embodiment will be briefly described. The details of the IEEE 1394-1995 standard (hereinafter referred to as the IEEE 1394 standard) are described in detail in "IEE. Bus ".
[0022]
(1) Overview
FIG. 2 shows an example of a communication system (hereinafter, a 1394 network) including nodes having a digital interface (hereinafter, a 1394 interface) based on the IEEE 1394 standard. The 1394 network constitutes a bus network capable of communicating serial data.
[0023]
In FIG. 2, nodes A to F are connected via a communication cable conforming to the IEEE 1394 standard. These nodes A to H are electronic devices such as a PC (Personal Computer), a digital VTR (Video Tape Recorder), a DVD (Digital Video Disc) player, a digital camera, a hard disk, and a monitor.
The connection method of the 1394 network corresponds to the daisy chain method and the node branch method, and enables connection with a high degree of freedom.
[0024]
In the 1394 network, for example, when an existing device is deleted, a new device is added, or the power of the existing device is turned on / off, the bus is automatically reset. By performing the bus reset, the 1394 network can automatically recognize a new connection configuration and assign ID information to each device. With this function, the 1394 network can always recognize the connection configuration of the network.
[0025]
The 1394 network has a function of relaying data transferred from another device. With this function, all devices can grasp the operation status of the bus.
[0026]
Further, the 1394 network has a function called Plug & Play. With this function, the connected device can be automatically recognized only by connecting without turning off the power of all devices.
[0027]
Further, the 1394 network supports a data transfer rate of 100/200/400 Mbps. A device having a higher data transfer rate can support a lower data transfer speed, so that devices corresponding to different data transfer speeds can be connected.
[0028]
Further, the 1394 network supports two different data transfer schemes (ie, Asynchronous transfer mode and Isochronous transfer mode).
[0029]
The Asynchronous transfer mode is effective when transferring data (that is, control signals, file data, and the like) that is required to be transferred asynchronously as necessary. In addition, the isochronous transfer mode is effective when transferring data (that is, video data, audio data, and the like) required to continuously transfer a predetermined amount of data at a constant data rate.
The Asynchronous transfer mode and the Isochronous transfer mode can be mixed in each communication cycle (usually one cycle is 125 μS). Each transfer mode is executed after transfer of a cycle start packet (hereinafter, CSP) indicating the start of a cycle.
[0030]
Note that in each communication cycle period, the isochronous transfer mode is set to have a higher priority than the asynchronous transfer mode. The transfer band in the isochronous transfer mode is guaranteed in each communication cycle.
[0031]
(2) Architecture
Next, components of the 1394 interface will be described with reference to FIG.
The 1394 interface is functionally composed of a plurality of layers (layers). In FIG. 3, the 1394 interface is connected to a 1394 interface of another node via a communication cable 301 conforming to the IEEE 1394 standard. Further, the 1394 interface has one or more communication ports 302, and the communication ports 302 are connected to a physical layer 303 included in a hardware unit.
[0032]
In FIG. 3, the hardware unit includes a physical layer 303 and a link layer 304. The physical layer 303 performs physical and electrical interfaces with other nodes, detection of bus resets and associated processing, encoding / decoding of input / output signals, arbitration of bus use rights, and the like. The link layer 304 generates and transmits and receives communication packets, controls a cycle timer, and the like.
[0033]
In FIG. 3, the firmware unit includes a transaction layer 305 and a serial bus management 306. The transaction layer 305 manages Asynchronous transfer mode and provides various transactions (read, write, lock). The serial bus management 306 provides functions for controlling the own node, managing the connection state of the own node, managing ID information of the own node, and managing resources of the serial bus network based on a CSR architecture described later.
[0034]
As described above, the hardware section and the firmware section substantially constitute a 1394 interface, and the basic configuration thereof is defined by the IEEE 1394 standard.
[0035]
The application layer 307 included in the software unit differs depending on the application software used, and controls how data is communicated on the network. For example, in the case of moving image data of a digital VTR, it is specified by a communication protocol such as the AV / C protocol.
[0036]
(2-1) Link layer 304
FIG. 4 is a diagram showing services that the link layer 304 can provide. In FIG. 4, the link layer 304 provides the following four services. That is, (1) a link request (LK_DATA.request) for requesting the response node to transfer a predetermined packet, (2) a link notification (LK_DATA.indication) for notifying the response node of reception of the predetermined packet, (3) A) a link response (LK_DATA.response) indicating that an acknowledgment has been received from the responding node; and (4) a link confirmation (LK_DATA.confirmation) confirming the acknowledgment from the requesting node. It should be noted that the link response (LK_DATA.response) does not exist in the case of the broadcast communication and the transfer of the isochronous packet.
Further, the link layer 304 realizes the above-mentioned two types of transfer methods, that is, the asynchronous transfer mode and the isochronous transfer mode, based on the above-mentioned service.
[0037]
(2-2) Transaction layer 305
FIG. 5 illustrates services that can be provided by the transaction layer 305. In FIG. 5, the transaction layer 305 provides the following four services. That is, (1) a transaction request (TR_DATA.request) for requesting a predetermined transaction to the response node, (2) a transaction notification (TR_DATA.indication) for notifying the reception node of the reception of the predetermined transaction request, (3). A transaction response (TR_DATA.response) indicating that status information (including data in the case of write or lock) has been received from the responding node, and (4) a transaction confirmation (TR_DATA.confirmation) confirming status information from the requesting node. ).
[0038]
The transaction layer 305 manages Asynchronous transfer based on the above-described service, and performs the following three types of transactions: (1) read transaction, (2) write transaction, and (3) lock transaction. Realize.
(1) In a read transaction, a requesting node reads information stored at a specific address of a responding node.
(2) In a write transaction, a requesting node writes predetermined information to a specific address of a responding node.
(3) In the lock transaction, the request node transfers the reference data and the update data to the response node, compares the information of the specific address of the response node with the reference data, and specifies the specific address according to the comparison result. Is updated to the update data.
[0039]
(2-3) Serial bus management 306
The serial bus management 306 can specifically provide the following three functions. The three functions are (1) node control, (2) isochronous resource manager (hereinafter, IRM), and (3) bus manager.
(1) The node control provides a function of managing the above-described layers and managing Asynchronous transfer executed with another node.
(2) The IRM provides a function of managing Isochronous transfer performed between other nodes. Specifically, it manages information necessary for assigning a transfer bandwidth and a channel number, and provides this information to other nodes.
The IRM exists solely on the local bus, and is dynamically selected from other candidates (nodes having an IRM function) at each bus reset. The IRM may provide some of the functions (such as connection configuration management, power supply management, and speed information management) that can be provided by a bus manager described later.
(3) The bus manager has an IRM function and provides a more advanced bus management function than the IRM. More specifically, more advanced power management (information on whether or not power can be supplied via a communication cable, whether or not power must be supplied for each node, etc.), more advanced speed information It performs management (management of the maximum transfer rate between each node), management of a more advanced connection configuration (creation of a topology map), optimization of a bus based on the management information, and the like, and further transfers the information to another node. It has a function to provide.
[0040]
Also, the bus manager can provide services for controlling the serial bus network to the application. Here, the services include a serial bus control request (SB_CONTROL.request), a serial bus event control confirmation (SB_CONTROL.confirmation), a serial bus event notification (SB_CONTROL.indication), and the like.
[0041]
SB_CONTROL. The request is a service for requesting a bus reset by an application. SB_CONTROL. The confirmation is defined as SB_CONTROL. This is a service for confirming the request to the application. SB_CONTROL. Indication is a service for notifying an application of an event that occurs asynchronously.
[0042]
(3) Address specification
FIG. 6 is a diagram illustrating an address space in the 1394 interface. The 1394 interface defines a 64-bit address space according to a CSR (Command and Status Register) architecture conforming to ISO / IEC 13213: 1994.
[0043]
In FIG. 6, the first 10-bit field 601 is used for an ID number specifying a predetermined bus, and the next 6-bit field 602 is used for an ID number specifying a predetermined device (node). The upper 16 bits are called “node ID”, and each node identifies another node by this node ID. Also, each node can perform communication in which the other party is identified using the node ID.
[0044]
The remaining 48-bit field specifies the address space (256 Mbyte structure) of each node. This address space is called a node address space. The 20-bit field 603 specifies a plurality of areas constituting the address space.
[0045]
In the field 603, the portion of "0 to 0xFFFFD" is called a memory space. The “0xFFFFE” portion is called a private space, and is an address that can be freely used by each node. The portion of “0xFFFFFF” is called a register space and stores common information between nodes connected to the bus. Each node can manage communication between the nodes by using the information of the register space.
[0046]
The last 28-bit field 604 specifies the address where common or unique information is stored in each node.
For example, in the register space, the first 512 bytes are used for CSR architecture core (CSR core) registers. FIG. 7 shows addresses and functions of information stored in the CSR core register. The offset in the figure is a relative position from “0xFFFFF00000000”.
[0047]
The next 512 bytes are used as a register for the serial bus. FIG. 8 shows addresses and functions of information stored in the serial bus register. The offset in the figure is a relative position from “0xFFFFF0000200”.
[0048]
The next 1024 bytes are used for the Configuration ROM.
[0049]
The configuration ROM has a minimum format and a general format, and is arranged from “0xFFFFF0000400”. FIG. 9 shows a minimum configuration ROM. In FIG. 9, the vendor ID is a 24-bit numerical value uniquely assigned to each vendor by IEEE.
[0050]
FIG. 10 shows a general configuration ROM. In FIG. 10, the above-described vendor ID is stored in the Root Directory 1002. The Bus Info Block 1001 and the Root Leaf 1005 can hold a node unique ID as unique ID information for identifying each node.
[0051]
Here, the node unique ID is set to a unique ID capable of specifying one node regardless of a maker and a model. The node unique ID is composed of 64 bits, the upper 24 bits indicate the above-described vendor ID, and the lower 48 bits indicate information (for example, a node serial number or the like) that can be freely set by a manufacturer that manufactures each node. The node unique ID is used, for example, when a specific node is continuously recognized before and after a bus reset.
[0052]
In FIG. 10, the Root Directory 1002 can hold information on basic functions of the node. Detailed function information is stored in a subdirectory (Unit Directories 1004) offset from the Root Directory 1002. In the Unit Directories 1004, for example, information on software units supported by the node is stored. Specifically, information on a data transfer protocol for performing data communication between nodes, a command set for defining a predetermined communication procedure, and the like are held.
[0053]
In FIG. 10, device-specific information can be stored in the Node Dependent Info Directory 1003. The Node Dependent Info Directory 1003 is offset by the Root Directory 1002.
[0054]
Further, in FIG. 10, Vendor Dependent Information 1006 can hold information unique to a vendor that manufactures or sells a node.
[0055]
The remaining area is called a unit space, and specifies an address in which information unique to each node, for example, identification information (company name, model name, etc.) of each device, use conditions, and the like are stored. FIG. 11 shows addresses and functions of information stored in the serial bus device register in the unit space. The offset in the figure is a relative position from “0xFFFFF0000800”.
[0056]
In general, if it is desired to simplify the design of heterogeneous bus systems, each node should use only the first 2048 bytes of the register space. In other words, it is desirable that the configuration is made up of 4096 bytes including the CSR core register, the serial bus register, the configuration ROM and the first 2048 bytes of the unit space.
[0057]
(4) Communication cable configuration
FIG. 12 is a sectional view of a communication cable conforming to the IEEE 1394 standard.
[0058]
The communication cable includes two twisted pair signal lines and a power supply line. By providing the power supply line, the 1394 interface can supply power to a device whose main power is turned off, a device whose power is reduced due to a failure, and the like. The voltage of the power supply flowing in the power supply line is specified to be 8 to 40 V, and the current is specified to be the maximum current DC 1.5 A.
[0059]
An information signal encoded by a DS-Link (Data / Strobe Link) encoding method is transmitted to the two twisted pair signal lines. FIG. 13 is a diagram illustrating the DS-Link coding scheme.
[0060]
This DS-Link coding scheme is suitable for high-speed serial data communication, and its configuration requires two pairs of twisted pairs. One twisted pair carries a data signal, and the other twisted pair sends a strobe signal. The receiving side can reproduce the clock by taking the exclusive OR of the data signal and the strobe signal received from the two sets of signal lines.
[0061]
By using the DS-Link coding method, the 1394 interface has the following advantages, for example. (1) Transfer efficiency is higher than other encoding methods. (2) No PLL circuit is required, and the circuit size of the controller LSI can be reduced. (3) Since there is no need to send information indicating the idle state, the transceiver circuit can be easily put into the sleep state, and power consumption can be reduced.
[0062]
(5) Bus reset
The 1394 interface of each node can automatically detect that a change has occurred in the network connection configuration. In this case, the 1394 network performs a process called a bus reset according to the following procedure. The change in the connection configuration can be detected by the change in the bias voltage applied to the communication port provided in each node.
[0063]
A node that has detected a change in the network connection configuration (for example, an increase or decrease in the number of nodes due to insertion / removal of a node, power ON / OFF of a node, or the like) or a node that needs to recognize a new connection configuration is connected via the 1394 interface. And transmits a bus reset signal on the bus.
[0064]
The 1394 interface of the node that has received the bus reset signal transmits the occurrence of the bus reset to its own link layer 304 and transfers the bus reset signal to another node. The node that has received the bus reset signal clears the network connection configuration and the node ID assigned to each device that have been recognized so far. After all the nodes finally detect the bus reset signal, each node automatically performs initialization processing (that is, recognition of a new connection configuration and assignment of a new node ID) accompanying the bus reset.
[0065]
The bus reset may be started by the application layer 307 directly issuing a command to the physical layer 303 under the control of the host, in addition to the start by the change in the connection configuration as described above. It is possible.
[0066]
Further, when the bus reset is activated, the data transfer is temporarily suspended, and is resumed under a new network after the completion of the initialization processing accompanying the bus reset.
[0067]
(6) Sequence after starting bus reset
After the start of the bus reset, the 1394 interface of each node automatically recognizes a new connection configuration and assigns a new node ID. Hereinafter, a basic sequence from the start of the bus reset to the node ID assignment processing will be described with reference to FIGS.
[0068]
FIG. 14 is a diagram illustrating a state after activation of the bus reset in the 1394 network of FIG.
[0069]
In FIG. 14, node A has one communication port, node B has two communication ports, node C has two communication ports, node D has three communication ports, node E has one communication port, and node F has one communication port. It has a port. The communication port of each node is provided with a port number for identifying each port.
[0070]
Hereinafter, the process from the start of the bus reset to the assignment of the node ID in FIG. 14 will be described with reference to the flowchart in FIG.
[0071]
In FIG. 15, each of the nodes A to F configuring the 1394 network constantly monitors whether or not a bus reset has occurred (step S1501). When a bus reset signal is output from a node that detects a change in the connection configuration, each node executes the following processing.
[0072]
After the occurrence of the bus reset, each node declares a parent-child relationship between the respective communication ports (step S1502).
[0073]
Each node repeats the processing of step S1502 until the parent-child relationship between all nodes is determined (step S1503).
[0074]
After the parent-child relationship between all nodes is determined, the 1394 network determines a node that performs network arbitration, that is, a route. (Step S1504).
[0075]
After determining the route, each of the 1394 interfaces of each node executes a task of automatically setting its own node ID (step S1505).
[0076]
Until node IDs are set for all nodes, each node executes the processing of step S1505 based on a predetermined procedure (step S1506).
[0077]
After the node IDs are finally set for all the nodes, each node executes Isochronous transfer or Asynchronous transfer (step S1507).
[0078]
While executing the processing in step S1507, the 1394 interface of each node monitors again for the occurrence of the bus reset. If a bus reset has occurred, the processing after step S1501 is executed again.
[0079]
Through the above procedure, the 1394 interface of each node can automatically execute recognition of a new connection configuration and assignment of a new node ID every time a bus reset is activated.
[0080]
(7) Determination of parent-child relationship
Next, the process of step S1502 shown in FIG. 15 (that is, the process of recognizing the parent-child relationship between the nodes) will be described in detail with reference to FIG.
[0081]
In FIG. 16, after the occurrence of the bus reset, each of the nodes A to F on the 1394 network confirms the connection state (connected or not connected) of its own communication port (step S1601).
[0082]
After checking the connection state of the communication ports, each node counts the number of communication ports (hereinafter, connection ports) connected to other nodes (step S1602).
[0083]
If the result of the processing in step S1602 is that the number of connection ports is one, the node recognizes that it is a “leaf” (step S1603). Here, a leaf is a node connected to only one node.
[0084]
The node serving as a leaf declares to the node connected to the connection port that "it is a child (Child)" (step S1604). At this time, the leaf recognizes that the connection port is “parent port (communication port connected to the parent node)”.
[0085]
Here, the declaration of the parent-child relationship is first made between the leaf and the branch, which are the ends of the network, and then sequentially made between the branches. The parent-child relationship between the nodes is determined in order from the communication port that can make the declaration earlier. The communication port that is declared as a child between the nodes is recognized as a “parent port”, and the communication port that has received the declaration is a “child port (communication port connected to the child node)”. It is recognized that there is. For example, in FIG. 14, nodes A, E, and F declare a parent-child relationship after recognizing that they are leaves. As a result, child-parent is determined between nodes AB, child-parent is determined between nodes ED, and child-parent is determined between nodes FD.
[0086]
If the result of the processing in step S1602 is that the number of connection ports is two or more, the node recognizes itself as a “branch” (step S1605). Here, a branch is a node connected to two or more nodes.
[0087]
The branch node receives a declaration of the parent-child relationship from the node of each connection port (step S1606). The connection port that has accepted the declaration is recognized as a “child port”.
[0088]
After recognizing one connection port as a “child port”, the branch detects whether or not there are two or more connection ports for which a parent-child relationship has not yet been determined (that is, undefined ports) (step S1607). As a result, when there are two or more undefined ports, the branch performs the operation of step S1606 again.
[0089]
As a result of step S1607, if there is only one undefined port, the branch recognizes that the undefined port is a “parent port”, and “owns a child” for a node connected to the port. Is declared (steps S1608 and S1609).
[0090]
Here, the branch cannot declare itself as a child to other nodes until the remaining undefined port becomes one. For example, in FIG. 14, nodes B, C, and D recognize that they are branches and accept declarations from leaves or other branches. After the parent-child relationship between DE and DF is determined, the node D declares the parent-child relationship to the node C. Further, the node C that has received the declaration from the node D has declared the parent-child relationship with the node B.
[0091]
If there is no undefined port as a result of the processing in step S1608 (that is, if all the connection ports of the branch have become parent ports), the branch recognizes that it is the root itself. . (Step S1610).
[0092]
For example, in FIG. 14, a node B in which all of the connection ports are parent ports is recognized by another node as a route for mediating communication on the 1394 network. Here, although the node B is determined to be the root, if the timing of declaring the parent-child relationship of the node B is earlier than the timing of declaring the node C, another node may be the root. That is, depending on the timing of declaration, any node may be the root. Therefore, even with the same network configuration, the same node does not always become the root.
[0093]
By declaring the parent-child relationship of all connection ports in this manner, each node can recognize the connection configuration of the 1394 network as a hierarchical structure (tree structure) (step S1611). The above-mentioned parent node is higher in the hierarchical structure, and the child node is lower in the hierarchical structure.
[0094]
(8) Assignment of node ID
FIG. 17 is a flowchart illustrating in detail the process of step S1505 (that is, the process of automatically assigning the node ID of each node) illustrated in FIG. Here, the node ID is composed of a bus number and a node number. In this embodiment, it is assumed that each node is connected to the same bus, and that each node is assigned the same bus number. .
[0095]
In FIG. 17, the root gives the node ID setting permission to the communication port having the smallest number among the child ports to which the node whose node ID is not set is connected (step S1701).
[0096]
In FIG. 17, after setting the node IDs of all the nodes connected to the child port with the smallest number, the root sets the child port as already set, and performs the same control for the next smallest child port. Do. Finally, after the ID setting of all nodes connected to the child port is completed, the node ID of the root itself is set. Note that the node numbers included in the node ID are basically assigned 0, 1, 2,... In the order of leaf and branch. Therefore, the route will have the highest node number.
[0097]
In step S1701, the node that has obtained the setting permission determines whether or not there is a child port including a node whose node ID has not been set among its own child ports (step S1702).
[0098]
If a child port including an unset node is detected in step S1702, the node that has obtained the above setting permission performs control so as to give the setting permission to the node directly connected to the child port (step S1703). ).
[0099]
After the processing in step S1703, the node that has obtained the setting permission determines whether or not there is a child port including a node whose node ID has not been set among its own child ports (step S1704). Here, if the existence of the child port including the unset node is detected after the processing of step S1704, the node executes the processing of step S1703 again.
[0100]
If no child port including an unset node is detected in step S1702 or S1704, the node that has obtained the setting permission sets its own node ID (step S1705).
[0101]
The node that has set its own node ID broadcasts a self-ID packet including its own node number, information on the connection state of the communication port, and the like (step S1706). The broadcast means transferring a communication packet of a certain node to an unspecified number of nodes constituting the 1394 network.
[0102]
Here, each node can recognize the note number assigned to each node by receiving the self ID packet, and can know the node number assigned to itself. For example, in FIG. 14, the node B, which is the root, gives permission for node ID setting to the node A connected to the communication port with the minimum port number “# 1”. The node A assigns its own node number “No. 0” and sets a node ID including a bus number and a node number for itself. Further, the node A broadcasts a self ID packet including the node number.
[0103]
FIG. 18 shows a configuration example of the self ID packet. In FIG. 18, reference numeral 1801 denotes a field for storing a node number of a node which has transmitted a self ID packet; 1802, a field for storing information on a transfer rate that can be supported; 1803, a bus management function (such as the presence or absence of a bus manager's capability); A field 1804 for indicating the presence or absence is a field for storing information on characteristics of power consumption and supply.
[0104]
In FIG. 18, 1805 is a field for storing information (connection, non-connection, parent-child relationship of communication ports, etc.) relating to the connection state of the communication port having the port number "# 0", and 1806 is a port number "# 1". A field 1807 stores information (connection, non-connection, parent-child relationship of communication ports, etc.) related to the connection state of the communication port. This is a field for storing parent-child relationships of ports.
[0105]
If the node transmitting the self ID packet has the ability to become a bus manager, the contender bit shown in the field 1803 is set to “1”.
[0106]
Here, the bus manager refers to the bus power management (whether power can be supplied via a communication cable and whether power supply is necessary or not) based on various information included in the above-described self ID packet. And the like for each node), management of speed information (management of the maximum transfer speed between each node from information on transfer speeds that each node can support), management of topology map information (communication port The node has a function of managing the connection configuration of the network from the parent-child relationship information, optimizing the bus based on the topology map information, and providing the information to other nodes. With these functions, a node serving as a bus manager can perform bus management of the entire 1394 network.
[0107]
After the processing in step S1706, the node that has set the node ID determines whether there is a parent node (step S1707). If there is a parent node, the parent node executes the processing of step S1702 and subsequent steps again. Then, permission is given to a node for which a node ID has not yet been set.
[0108]
If there is no parent node, the node is determined to be the root itself. The root determines whether a node ID has been set for the nodes connected to all the child ports (step S1708).
[0109]
If the ID setting process has not been completed for all nodes in step S1708, the root grants ID setting permission to the child port having the lowest number among the child ports including the node (step S1701). After that, the process from step S1702 is executed.
[0110]
When the ID setting process for all nodes is completed, the root sets its own node ID (step S1709). After setting the node ID, the route broadcasts a self ID packet (step S1710).
[0111]
Through the above processing, the 1394 network can automatically assign a node ID to each node.
[0112]
Here, if a plurality of nodes have the bus manager capability after the node ID setting process, the node with the largest node number becomes the bus manager. That is, when the route having the maximum node number in the network has a function that can be the bus manager, the route is the bus manager.
[0113]
However, if the route does not have the function, the node having the next highest node number becomes the bus manager. Further, which node has become the bus manager can be grasped by checking the contender bit 1803 in the self ID packet broadcast by each node.
[0114]
(9) Arbitration
FIG. 19 is a diagram illustrating arbitration in the 1394 network of FIG.
[0115]
In the 1394 network, arbitration (arbitration) of the right to use the bus is always performed prior to data transfer. The 1394 network is a logical bus network. By relaying a communication packet transferred from each node to another node, the same communication packet can be transferred to all nodes in the network. Therefore, arbitration is required to prevent collision of communication packets. This allows only one node to transfer at a given time.
[0116]
FIG. 19A is a diagram illustrating a case where the node B and the node F have issued a bus use request.
[0117]
When the arbitration starts, the nodes B and F each issue a bus use request to the parent node. The parent node (that is, node C) that has received the request from node B relays the right to use the bus toward its parent node (that is, node D). This request is finally delivered to the arbitrating route (node D).
[0118]
The route receiving the bus use request determines which node uses the bus. This arbitration work can be performed only by the root node, and the node that wins the arbitration is given permission to use the bus.
[0119]
FIG. 19B is a diagram showing that the request of the node F is permitted and the request of the node B is rejected.
[0120]
The route sends a DP (Data prefix) packet to the node that has lost the arbitration to notify that the node has been rejected. The rejected node waits for a bus use request until the next arbitration.
[0121]
By controlling arbitration as described above, the 1394 network can manage the right to use the bus.
[0122]
(10) Communication cycle
The Isochronous transfer mode and the Asynchronous transfer mode can be mixed in a time division manner in each communication cycle period. Here, the period of the communication cycle is usually 125 μS.
[0123]
FIG. 20 is a diagram illustrating a case where the Isochronous transfer mode and the Asynchronous transfer mode are mixed in one communication cycle.
[0124]
The Isochronous transfer mode is executed prior to the Asynchronous transfer mode. The reason is that after the cycle start packet, the idle period (subaction gap) required to start the asynchronous transfer is set to be longer than the idle period (isochronous gap) required to start the isochronous transfer. Because it is. As a result, Isochronous transfer is executed prior to Asynchronous transfer.
[0125]
In FIG. 20, at the start of each communication cycle, a cycle start packet (hereinafter, CSP) is transferred from a predetermined node. Each node can time the same time as the other nodes by adjusting the time using the CSP.
[0126]
(11) Isochronous transfer mode
The Isochronous transfer mode is a synchronous transfer method. Isochronous mode transfer can be executed for a predetermined period after the start of the communication cycle. In addition, the Isochronous transfer mode is always executed in each cycle in order to maintain real-time transfer.
[0127]
The isochronous transfer mode is a transfer mode particularly suitable for transferring data that requires real-time transfer, such as moving image data and audio data. The Isochronous transfer mode is not a one-to-one communication as in the Asynchronous transfer mode, but a broadcast communication. That is, a packet transmitted from a certain node is uniformly transferred to all nodes on the network. The acknowledgment (acknowledgement reply code) does not exist in the isochronous transfer.
[0128]
In FIG. 20, a channel e (ch e), a channel s (ch s), and a channel k (chk) indicate periods during which each node performs Isochronous transfer. In the 1394 interface, different channel numbers are given to distinguish a plurality of different isochronous transfers. This enables Isochronous transfer between a plurality of nodes. Here, the channel number does not specify the transmission destination, but merely gives a logical number for the data.
[0129]
The Isochronous gap shown in FIG. 20 indicates an idle state of the bus. After a certain period of time in the idle state, a node desiring Isochronous transfer determines that the bus can be used and executes arbitration.
[0130]
Next, FIG. 21 shows a format of a communication packet transferred based on the Isochronous transfer mode. Hereinafter, a communication packet transferred based on the Isochronous transfer mode is referred to as an Isochronous packet.
[0131]
In FIG. 21, the Isochronous packet includes a header section 2101, a header CRC 2102, a data section 2103, and a data CRC 2104.
[0132]
The header section 2101 has a field 2105 for storing the data length of the data section 2103, a field 2106 for storing the format information of the isochronous packet, a field 2107 for storing the channel number of the isochronous packet, a format of the packet, and processing to be executed. There is a field 2108 for storing a transaction code (tcode) for identifying, and a field 2109 for storing a synchronization code.
[0133]
(12) Asynchronous transfer mode
The Asynchronous transfer mode is an asynchronous transfer method. Asynchronous transfer can be performed after the end of the Isochronous transfer period until the next communication cycle starts (that is, until the CSP of the next communication cycle is transferred).
[0134]
In FIG. 20, a first subaction gap indicates a bus idle state. After the idle time reaches a fixed value, a node desiring asynchronous transfer determines that the bus can be used and executes arbitration.
[0135]
The node that has obtained the right to use the bus by arbitration transfers the packet shown in FIG. 22 to a predetermined node. The node receiving this packet returns an ack (reception confirmation return code) or a response packet after the ack gap.
[0136]
FIG. 22 is a diagram showing a format of a communication packet based on the Asynchronous transfer mode. Hereinafter, a communication packet transferred based on the Asynchronous transfer mode is referred to as an Asynchronous packet.
[0137]
In FIG. 22, the Asynchronous packet includes a header section 2201, a header CRC 2202, a data section 2203, and a data CRC 2204.
[0138]
In the header section 2201, a field 2205 indicates the node ID of a destination node, a field 2206 indicates a node ID of a source node, a field 2207 indicates a label indicating a series of transactions, and a field 2208 indicates a retransmission status. A code, a field 2209, a transaction code (tcode) for identifying a packet format and processing to be executed, a field 2210, a priority, a field 2211, a destination memory address, and a field 2212, data of a data portion The extended field 2213 stores an extended transaction code.
[0139]
Asynchronous transfer is one-to-one communication from a self-node to a partner node. The packet transferred from the transfer source node is distributed to each node in the network, but the address other than the address addressed to itself is ignored. Therefore, only the destination node can read the packet.
[0140]
When the time to transfer the next CSP is reached during Asynchronous transfer, the transfer is not forcibly interrupted, and after the transfer is completed, the next CSP is transmitted. Thus, when one communication cycle continues for 125 μS or more, the period of the next communication cycle is shortened accordingly. By doing so, the 1394 network can maintain a substantially constant communication cycle.
[0141]
(13) Device map
As means for the application to know the topology of the 1394 network in order to create a device map, there are the following means in the IEEE 1394 standard.
1. Read the bus manager's topology map register
2. Estimate from self ID packet at bus reset
However, in the above-mentioned means 1 and 2, although the topology of the cable connection order based on the parent-child relationship of each node is known, the topology of the physical positional relationship cannot be known (ports that are not mounted can be seen. There is a problem.)
[0142]
In addition, there is a means for storing information for creating a device map as a database other than the configuration ROM. In this case, a means for obtaining various information depends on a protocol for accessing the database.
[0143]
By the way, the configuration ROM itself and the function of reading the configuration ROM are necessarily possessed by devices complying with the IEEE1394 standard. Therefore, by storing information such as device position and function in the configuration ROM of each node and providing a function to read them from an application, each node can be operated independently of a specific protocol such as database access and data transfer. Can implement a so-called device map display function.
[0144]
The configuration ROM can store a physical position, a function, and the like as node-specific information, and can be used to realize a device map display function.
[0145]
In this case, as means for the application to know the 1394 network topology based on the physical positional relationship, the bus reads the configuration ROM of each node at the time of bus reset or at the time of a request from the user to know the 1394 network topology. That method becomes possible. Furthermore, not only the physical position of the node but also various node information such as functions are described in the configuration ROM. By reading the configuration ROM, not only the physical position of the node but also the function information of each node and the like can be obtained. Obtainable. When the application acquires the configuration ROM information of each node, an API that acquires arbitrary configuration ROM information of the designated node is used.
[0146]
By using such means, an application of a device on the IEEE 1394 network can create various device maps according to applications, such as a physical topology map, a function map of each node, and the like. It is also possible to select a device having a function.
[0147]
<Overview of 1394 Bridge>
The configuration of the present embodiment and the connection device will be described.
[0148]
Hereinafter, the technology of the IEEE 1394 bridge applied to the digital interface of the present embodiment will be briefly described. The IEEE 1394 bridge (hereinafter 1394 bridge) standard is being developed by the IEEE 1394.1 subcommittee.
[0149]
According to the 1394 standard, up to 63 nodes can be connected on one 1394 bus, and the number of hops is up to 16.
A 1394 bridge is generally used when 63 or more 1394 nodes are to be connected to the 1394 network, or when it is necessary to connect devices that need to make a connection of 16 hops or more because they are at remote locations.
[0150]
IEEE 1394 uses 64-bit fixed addressing according to the IEEE 1212 standard, and defines 10 bits as a bus ID. Therefore, a maximum of 1023 buses except for an ID 1023 specifying a local bus are connected via a 1394 bridge, and A network can be configured.
[0151]
The main function of the 1394 bridge is to control 1394 node transactions between buses via the bridge.
[0152]
In the case of a 1394 transaction, the node that issues the transaction and the destination node are specified using the node ID as described in the column of <Overview of IEEE 1394 Technology>. The 1394 bridge has, as a table, information such as topology information and node ID information of two buses to be connected, and enables bus-to-bus transactions by disclosing partner bus / node information to the two buses to be connected.
[0153]
Further, in the case of the 1394 bus, a change occurs in a connection form such as additional connection of a device node, or a bus reset occurs when a certain node intentionally gives an instruction. In order to perform the reallocation, a bus reset sequence and a node ID determination sequence are performed, and a new topology is generated. The details of this sequence have been described in the section of <Bus Reset Sequence> and <Node ID Determination Sequence> in <Overview of IEEE 1394 Technology>, and will not be described.
[0154]
Due to this characteristic, the topology / node ID information of the bus to be connected changes dynamically, and the bridge also updates the information.
[0155]
On the other hand, while the 1394 bus reset sequence is being performed, data transfer in the bus is interrupted, and a complicated sequence of reassigning node IDs is performed. Therefore, it is necessary to generate a bus reset sequence. Propagating the bus reset signal to other buses is considered very inefficient, so the 1394 bridge does not propagate one connected bus reset signal to the other bus.
[0156]
Other bridge functions include arbitration between 1394 bridges in a network with a plurality of buses connected to a plurality of bus bridges, and a packet routing function through bridge information exchange.
[0157]
The above is the description regarding the configuration and functions of the communication system configured using the 1394 interface.
[0158]
<Data transfer procedure>
Next, the transmitting device 1 and the receiving device 2 in FIG. 1 will be described. The transmitting device 1 transmits data to the receiving device 2 using the function provided by the transaction layer 305. Of course, both the transmitting device and the receiving device may be equal devices having a transmitting / receiving function. This embodiment discloses an intermediate layer protocol that provides a service to the application layer 307 by using the service of the transaction layer 305 in FIG. In the present embodiment, since the transaction 305 operates as described above, this intermediate layer protocol will be described. The application layer 307 provides data on the transmission side to, for example, a program that realizes the intermediate layer protocol. On the receiving side, for example, an application program specified by the received data is activated and the received data is processed. Hereinafter, the operation of the transmitting device and the receiving device will be described, but the target of the description is the intermediate layer protocol, and the procedures in the application layer and the transaction layer are omitted.
[0159]
FIG. 23 shows a node address space of transmitting apparatus 1 and receiving apparatus 2 shown in FIG. 1 of the present embodiment. The node address space is as described in FIG. 6 and is a memory space specified by a 48-bit address. In FIG. 23, a control window 2301 includes both the transmission device 1 and the reception device 2 and is used for connection control and data transfer flow control. In the present embodiment, the addresses in the node address space are described in the NodeDependentInfoDirectory of the ConfigROM 2300 of each device (not shown), and can be known from other nodes. The data window 2302 is included in the receiving device 2, and the transmitting device 1 transmits data to this area using the write transaction described with reference to FIG. The address and size of the data window 2302 are stored by the receiving device 2 and are updated as the data transfer progresses. Then, the receiving apparatus 2 notifies the transmitting apparatus 1 using the control window 2301 described above. The data image is an image obtained by mapping the file image transmitted from the transmission device 1 to the node address space, and the data window 2302 slides to cover this data image.
[0160]
FIG. 24 shows the data format of the control window. In the figure, a command 2401 describes a command for connection and flow control with 16-bit width data. The window address upper 2402 has a 16-bit width and indicates the upper 16 bits of the address in the node address space of the data window. The window address lower 2403 also indicates the lower 32 bits. The window size 2404 indicates the byte size of the data window in a 64-bit width.
[0161]
Commands of the same format as the control window shown in FIG. 24 are exchanged between the transmitting device and the receiving device. As with the data, this command is exchanged when a certain device writes to the control window 2301 by a write transaction of another device.
[0162]
FIG. 25 shows the values and meanings of the commands. The connection request command (C) 2501 is a command transmitted from the transmitting device to the receiving device for establishing a connection, and does not use a window address or a window size. The connection permission response command (A) 2502 is a response that is sent from the receiving device to the transmitting device and that permits connection in response to the connection request command, and uses a window address and a window size if necessary. The connection rejection response command (B) 2503 for the connection request is sent from the reception device to the transmission device, and is a response for rejecting the connection in response to the connection request command, and does not use the window address and the window size. The window notification command (N) 2504 is a command for notifying the transmitting device of the window address from the receiving device, and uses the window address and the window size. The disconnection request command (T) 2505 is a command for requesting disconnection of the connection from the transmitting device to the receiving device, and does not use the window address and the window size.
[0163]
FIG. 26 shows a state transition of the transmission device 1, which is realized by the CPU 12 executing a program stored in the ROM 13. In the figure, TX0 indicates an initial state, a TX1 connection response waiting state, TX2 indicates a data transmission state, TX3 indicates a window notification waiting state, and TX4 indicates a window detection state. TX0a indicates a state transition to TX1 due to transmission of a connection request to the receiving device 2. TX1a indicates a state transition to TX2 upon receipt of the connection permission response. TX1b indicates a state transition to TX0 due to a timeout due to a failure to receive a connection response or a reception of a connection rejection response. TX2a indicates a state transition to TX3 due to writing to the data window reaching the data window size. TX2b indicates a state transition to TX4 due to reception of the window notification. TX2c indicates a state transition to TX0 due to transmission of the end request. TX3a indicates a state transition to TX4 due to reception of the window notification. TX4a indicates a state transition to TX2 due to detection of a new window address and window size.
[0164]
As described above, once the connection is established, the data transmission state, the window notification waiting state, and the window detection state are changed along the path of TX2a, TX3a, TX4a or TX2b, TX4a until the connection is disconnected by the disconnection request. Transition.
[0165]
That is, the transmitting device stores the address and the size of the data window notified by the window notification from the receiving device in a memory (transmission data management memory). Then, each time data is transmitted, the transmission data management memory is updated according to the transmitted size. That is, the size of the transmitted data is subtracted from the remaining size displayed in the transmission data management memory. Then, if the remaining size becomes 0, that is, if the notified data window has no free space, it enters a window notification waiting state.
[0166]
If there is a window notification in the window notification waiting state or the data transmission state, a window detection state is set. In this state, the address and size of the data window are detected from the window notification, the contents of the transmission data management memory are updated with the detected address and size, and the state shifts to the data transmission state. The transmission data management memory is updated by updating the data window end address obtained from the address information and size information notified by the window notification to the data window end obtained from the data window address and size managed by the transmission data management memory. This is performed by updating the size information so that the address matches the address. This is because, when data transmission and window notification are interchanged, the address of the data window managed by the transmitting device has the latest value.
[0167]
Once the connection is thus set, the transmitting apparatus can repeat the update of the data window size notified of data transmission, and transmit large-sized data according to the data window size. When transmitting data, the receiving side can rearrange the received data in the order in which it was received, because the transmission order represents the data sequence itself, so that the transmitted data can be reconstructed and processed as a group of data. can do.
[0168]
FIG. 27 shows a state transition of the receiving device 2, which is realized by the CPU 22 executing a program stored in the ROM 23. In the figure, RX0 indicates an initial state, RX1 indicates a reception start state, RX2 indicates a data reception state, RX3 indicates a window update waiting state, and RX4 indicates a window update state. RX0a indicates a state transition to RX1 due to reception of a connection request. RX1a indicates a state transition to RX2 due to transmission of a connection permission response including a window notification. RX1b indicates a state transition to RX0 due to transmission of a connection rejection response. RX2a indicates a state transition to RX3 due to the reception data reaching the window size. RX2b indicates a state transition to RX4 due to received data processing. RX2c indicates a state transition to RX0 due to reception of the termination request. RX3a indicates a state transition to RX4 due to received data processing. RX4a indicates a state transition to RX2 due to window update.
[0169]
As described above, once the connection is established, the data reception state, the window update waiting state, and the window update state are changed along the path of RX2a, RX3a, RX4a or RX2b, RX4a until the connection is disconnected by the disconnection request. Transition.
[0170]
That is, the receiving device manages the empty data window based on the address information and the size information of the control window, and if the size is 0, that is, if the notified data window runs out of empty space, the receiving device enters a window update waiting state.
[0171]
In the window update waiting state or the data reception state, if there is a free area available for the data window, or if a new area is available, the state is the window update state. In this state, the address and size of the data window included in the control window are updated, and an updated window notification is issued to the transmitting device. Then, the state returns to the data receiving state.
[0172]
Thus, once the connection is established, the receiving apparatus can repeat data reception, data window update, and window notification, and can transmit even large-sized data according to the data window size. At the time of data reception, since the reception order represents the data sequence itself, the receiving apparatus can process the received data as a set of data by rearranging the received data in the order in which they were received. For example, data received by each window size is stored as a series of data in a buffer specified by the application program, and it is determined that all data in the connection has been received by receiving a disconnection request, and the data is transferred to the application program. .
[0173]
Hereinafter, the data communication process will be described with reference to an example of the data communication flow. The transmitting device 1 transfers a file of size n bytes stored in the external device 15 to the receiving device 2, and the receiving device 2 stores the received file in the external device 25. FIG. 28 shows an example of a data communication flow. The command name is represented by an abbreviated name (shown in parentheses) as shown in FIG. 25, and the numerical value in parentheses following the command name indicates (window upper address: window lower address, window size). As shown in FIG. 25, a command not using a parameter is indicated by (0: 0, 0).
[0174]
In FIG. 28, a command C (0: 0,0) 2801 indicates a connection request from the transmitting device 1 to the receiving device 2 and writes the request into the control window of the receiving device 2 using a write transaction. As a result, the state of the transmitting device 1 changes from the initial state TX0 to the connection response waiting state TX1 (TX1a).
[0175]
The receiving device 2 receives the connection request, and its state transits from the initial state RX0 to the reception start state RX1 (RX1a). To permit transmission, the receiving device 2 writes a connection permission response command A (1: 0, 3072) 2802 in the control window 2301 of the transmitting device 1 using a block write transaction. The state of the receiving device 2 changes from the reception start state RX1 to the data reception state RX2 by transmitting a connection permission response (RX1a). The transmission device 1 receives the connection permission response, detects the upper address 1, the lower address 0, and the size of 3072 bytes of the data window of the reception device 2, and the state transits from the response waiting state TX1 to the data transmission state TX2 ( TX1a). Here, the transmitting device 1 reads out the window size of 3072 bytes from the beginning of the file and prepares for transmission.
[0176]
Command W (1: 0, 1024) 2803 indicates data transfer from transmitting apparatus 1 to receiving apparatus 2. The transmitting device 1 sends the first file read out using the write transaction to the address (010000H: H represents a hexadecimal number) specified by the upper address 1 and the lower address 0 in the node address space of the receiving device 2. 1024 bytes of data are written. The subsequent command W (1: 1024,1024) 2804 also indicates data transfer from the transmitting device 1 to the receiving device 2. The transmitting device 1 uses the write transaction to write the next 1024 bytes to the address (010400H) specified by the upper address 1 and the lower address 1024 in the node address space of the receiving device 2. The same applies to W (1: 2048,1024) 2805. The transmitting device 1 uses the write transaction to write the next 1024 bytes to the address (010800H) specified by the upper address 1 and the lower address 2048 in the node address space of the receiving device 2.
[0177]
Here, the transmitting device 1 completes data transmission of 3072 bytes (1024 bytes × 3 times), which is the data window size notified from the receiving device 2. Then, the state transits from the data transmission state TX2 to the window notification waiting state TX3 (TX2a).
[0178]
On the other hand, receiving apparatus 2 processes the received data after receiving W (1: 1024,1024) 2804, updates the data window to upper address 1, lower address 2048, size 3072 bytes (RX2b), and sends window notification N (1: 2048, 3072) 2806 is transmitted to the control window of the transmitting device 1 using a write transaction (RX4a).
[0179]
Thereafter, the receiving device 2 receives W (1: 2048,1024) 2805 from the transmitting device 1. As a result, of 3072 bytes, which is the size of the data window specified by the upper address 1 and the lower address 2048, the free area becomes 2048 bytes from the address (010C00H) specified by the upper address 1 and the lower address 3072.
[0180]
The transmitting device 1 receives the window notification N (1: 2048, 3072) 2806 after transmitting the W (1: 2048, 1024) 2805 (TX3a), and specifies the data window of the receiving device 2 by the upper address 1 and the lower address 2048. Starting from the address to be detected, it is detected that the size is 3072 bytes. As a result, the state of the transmission device 2 changes from the window detection state TX4 to the data transmission state TX2 (TX4a). Since the transmitting apparatus 1 has already transmitted W (1: 2048,1024) 2805, the next 2048 bytes are read from the file, and the subsequent address (W (1: 2048,1024) 2805) of the memory space written by W (1: 2048,1024) 2805 is read. 010C00H) to perform data transmission. That is, W (1: 3072,1024) 2807 is transmitted using a write transaction. Similarly, W (1: 4096,1024) 2808 is written to the memory space of the receiving device 2 by using a write transaction from the subsequent address written in W (1: 3072,1024) 2807. As a result, data transmission to the data window of 3072 bytes in size whose start address is specified by the upper address 1 and the lower address 2048 of the receiving device 2 is completed, and the transmitting device 1 transits to the window waiting state TX3 (TX2a). ).
[0181]
Upon receiving W (1: 2048,1024) 2805, W (1: 3072,1024) 2807, and W (1: 4096,1024) 2808, the receiving apparatus 2 transitions from the data reception state RX2 to the window update waiting state RX3. (RX2a). Then, the received data is processed, and the address of the data window is added to the address specified by the upper address 1 and the lower address 2048 by the received 3072 bytes, that is, the upper address is set to 1, and the lower address is set to 5120. , The size is updated to 3072 bytes (RX3a). The updated data window address and size are transmitted by writing a window notification command N (1: 5120, 3072) 2809 into the control window of the transmitting device 1 using a write transaction (RX4a).
[0182]
The transmitting device 1 receives the window notification, N (1: 5120,3072) 2809 (TX3a), detects the upper address 1, the lower address 5120, and the size of 3072 bytes of the data window of the receiving device 2, and determines from the window detection state TX4. The state transits to the data transmission state TX2 (TX4a).
[0183]
Thereafter, the transmitting device 1 and the receiving device 2 repeat the above-described processing, and transfer the data from W (1: 4096,1024) 2802808 to the last data W (1: n−r, r) 2811. After that, the transmitting device 1 transmits a disconnection request T (0: 0, 0) 2812 to the control window of the receiving device 2 using a write transaction, and returns to the initial state TX0 (TX2b).
[0184]
When receiving the connection request T (0: 0,0) 2812, the receiving device 2 processes the received data, ends the receiving process, and returns to the initial state RX0 (RX2b).
[0185]
As described above, the transmitting device 1 can transfer a file of a specified size by writing data of a specified byte from a specified address in the node address space of the receiving device 2.
[0186]
That is, the transmitting device first issues a connection request to the receiving device prior to data transmission, and attempts to establish a connection. Upon receiving the connection request, the receiving device notifies the memory space for data reception by its address and size. This establishes a connection. The transmitting device transmits data by writing transmission data to the memory space notified through the connection. At this time, the transmission device compares the remaining size of the transmission data with the notified free space of the memory space, and transmits the data in a size equal to or smaller than the notified free space of the memory space. Further, the receiving apparatus secures a memory space for reception in accordance with the use state of the resource, and notifies the transmitting side of the information so that data reception can be performed regardless of the data size.
[0187]
As a result, a large amount of data can be transmitted using a memory that can be secured by the receiving side for data reception.
[0188]
Since the memory space prepared by the receiving side can be dynamically changed each time data is transmitted by the transmitting side, it is possible to efficiently use the memory space secured by the receiving side according to the use state of the resource.
[0189]
Further, at the time of transmission, there is no need to transmit data for the free space. The transmitting side can control the data flow of the transaction layer by transmitting the data in an appropriate size. In the present embodiment, data transmission is performed in units of 1024 bytes regardless of the size of the reception memory space. Transaction processing is performed using the asynchronous mode, and since the asynchronous mode has a lower priority than the isochronous mode, there is a possibility that a sufficient band for a transaction cannot be secured. Even in such a case, by transmitting data in segments each having a certain size or less, it is possible to prevent timeout of data transmission and retransmission accompanying the data transmission, and suppress unnecessary traffic.
[0190]
In the 1394 network, the nodes are assumed to be various devices such as home appliances. Such devices do not always have sufficient data processing capabilities. In the present embodiment, even in such a case, the receiving device can take the initiative based on the window notification and control the bandwidth of the connection set between the transmitting device and the receiving device.
[0191]
(Second embodiment)
As a second embodiment of the present invention, a case will be described in which the receiving device reads data from an area in the node address space of the transmitting device to perform transfer. The configuration of the present embodiment is the same as the configuration of the first embodiment, and FIGS. 1, 23, 24, and 25 are used in the description of the present embodiment.
[0192]
FIG. 1 is a block diagram showing the present embodiment, and the configuration is the same as that of the above-described first embodiment. Next, the transmitting device 1 and the receiving device 2 will be described.
[0193]
FIG. 23 is a diagram illustrating a node address space of the transmitting device 1 and the receiving device 2 according to the present embodiment. In the figure, a control window is provided for both the transmitting device 1 and the receiving device 2, and is used for connection control and data transfer flow control. In the present embodiment, the address is described in NodeDependentInfoDirectory of the ConfigROM of each device (not shown) and can be known from other nodes. The data window is provided in the transmission device 1, and the reception device 2 receives data from this area using a read transaction. The address and the size are updated as the data transfer progresses, and are notified from the transmitting device 1 to the receiving device 2 using the control window described above. The data image is an image obtained by mapping the file image transmitted from the transmission device 1 to the node address space, and the data window slides the address so as to cover the data image.
[0194]
FIG. 24 shows the data format of the control window. In the figure, the command, the window address upper order, the window address lower order, and the window size are the same as those in the first embodiment. As shown in FIG. 25, the values and meanings of the commands are the same as those in the first embodiment.
[0195]
FIG. 29 shows a state transition of the transmission device 1, which is realized by the CPU 12 executing a program stored in the ROM 13. In the figure, TX10 indicates an initial state, TX11 connection response waiting state, TX12 indicates a window update state, TX13 indicates a data transmission state, and TX14 indicates a window update wait state. TX10a indicates a state transition to TX11 due to transmission of a connection request to the receiving device 2. TX11a indicates a state transition to TX12 due to the reception of the connection response. The TX 11b cannot receive a connection permission response and indicates a state transition to the TX 10 due to a timeout or a reception of a connection rejection response. TX12a indicates a state transition to TX13 due to transmission of the window notification. TX12b indicates a state transition to TX10 due to transmission of a termination request. TX13a indicates a state transition to TX14 when the transmission data reaches the window size. TX13b indicates a state transition to TX12 by updating the data window. TX14a indicates a state transition to TX12 by updating the data window.
[0196]
As described above, once the connection is established, the data transmission state, the window update wait state, and the window update state are changed along the path of TX13a, TX14a, TX12a or TX12a, TX13b until the connection is disconnected by the disconnection request. Transition.
[0197]
That is, the transmitting device stores the transmission data in the data window, and notifies the receiving device of the address and the size through the control window to enter the data transmission state. In this state, each time the receiving device reads data from the data window, the address and size of the control window are updated according to the amount of data read. Then, when the size becomes 0, that is, when the data is completely read from the data window, the state becomes the window update waiting state TX14.
[0198]
In the window update wait state or the data transmission state, when new data is prepared in the data window, the state transits to the window update state TX12, updates the control window with the address and size of the data window, and issues a window notification to the receiving device. I do. Then, the state becomes the data transmission state TX13.
[0199]
Once the connection is set in this way, the transmitting device repeats preparation of transmission data, update of the data window, and window notification, and can transmit even large-sized data according to the data window size. At the time of data transmission, since the transmission order represents the data sequence itself, the receiving side can process the received data as a group of data by rearranging the received data in the received order.
[0200]
FIG. 30 shows a state transition of the receiving device 2, which is realized by the CPU 22 executing a program stored in the ROM 23. In the figure, RX10 indicates an initial state, RX11 indicates a reception start state, RX12 indicates a window notification waiting state, RX13 indicates a window detection state, and RX14 indicates a data reception state. RX10a indicates a state transition to RX11 due to reception of a connection request. RX11a indicates a state transition to RX12 due to transmission of a connection permission response. RX11b indicates a state transition to RX10 due to transmission of a connection rejection response. RX12a indicates a state transition to RX13 due to the reception of the window notification. RX12b indicates a state transition to RX10 upon receipt of the end request. RX13a indicates a state transition to RX14 due to window detection. RX14a indicates a state transition to RX12 due to the reception data reaching the window size. RX14b indicates a state transition to RX13 due to the reception of the window notification in the data reception state.
[0201]
As described above, once the connection is established, the window notification waiting state, the window detection state, and the data reception state are changed along the path of RX12a, RX13a, RX14a or RX14b, RX13a until the connection is disconnected by the disconnection request. Transition.
[0202]
That is, the receiving device stores the address and size of the data window notified by the window notification from the transmitting device in a memory (received data management memory). Each time data is read from the notified data window, the address and size stored in the reception data management memory are updated according to the read size, and the address and size of the remaining data are stored in the reception data management memory. To manage. Then, when the transmitting device has exhausted all the data prepared, that is, when the remaining data size managed becomes 0, the state shifts from the receiving state RX14 to the window notification waiting state RX12.
[0203]
Then, if there is a window notification from the transmitting device in the window notification waiting state RX12 or the data reception state RX14, the state transits to the window detection state RX13. In the window detection state, the address and size of the data window displayed in the window notification are read, the received data display memory is updated, and the process returns to the data reception state RX14.
[0204]
Thus, once the connection is established, the receiving apparatus can repeat data reception, data window update, and window notification, and can transmit even large-sized data according to the data window size. At the time of data reception, since the reception order represents the data sequence itself, the receiving apparatus can process the received data as a set of data by rearranging the received data in the order in which they were received. For example, data received by each window size is stored as a series of data in a buffer specified by the application program, and it is determined that all data in the connection has been received by receiving a disconnection request, and the data is transferred to the application program. .
[0205]
Hereinafter, the data communication process will be described with reference to an example of the data communication flow. The transmitting device 1 transfers a file of size n bytes stored in the external device 15 to the receiving device 2, and the receiving device 2 stores the received file in the external device 25. FIG. 28 shows an example of a data communication flow. The command name is represented by an abbreviated name (shown in parentheses) as shown in FIG. 25, and the numerical value in parentheses following the command name indicates (window upper address: window lower address, window size). As shown in FIG. 25, a command not using a parameter is indicated by (0: 0, 0).
The transmitting device 1 transfers a file of size n bytes stored in the external device 15 to the receiving device 2, and the receiving device 2 stores the received file in the external device 25.
[0206]
FIG. 31 shows an example of a data communication flow.
[0207]
In the figure, C (0: 0,0) 3101 indicates a connection request from the transmitting device 1 to the receiving device 2 and writes the request into the control window of the receiving device 2 using a block write transaction. The state of the transmitting device 1 transits from TX10 to TX11 (TX11a). Upon receiving the connection request, the state of the receiving device 2 transits from RX10 to RX11 (RX11a). A (0: 0,0) 3102 indicates a connection permission response from the receiving device 2 and writes the response to the control window of the transmitting device 1 using a write transaction. The state of the receiving device 2 transmits a connection permission response and transits from RX11 to RX12 (RX11a). Upon receiving the connection permission response, the state of the transmitting device 1 transits from TX11 to TX12 (TX11a). At this time, the transmitting device 1 reads 3072 bytes from the beginning of the file, sets the upper address 1, the lower address 0, and the window size 3072 bytes of the node address space of the transmitting device 1 to be readable, and prepares for transmission.
[0208]
Next, N (1: 0, 3072) 3103 indicates a window notification from the transmitting device 1 to the receiving device 2, and the upper address 1, the lower address 0, and the window size 3072 bytes of the node address space of the transmitting device 1 can be read. Is transmitted to the control window of the receiving device 2 using a block write transaction (TX12a). When receiving the window notification, the receiving device 2 makes a state transition to RX13 (RX12a), and when detecting the updated data window of the transmitting device 1, makes a transition to RX14 (RX13a).
R (1: 0, 1024) 3104 indicates a read request from the receiving device 2 to the transmitting device 1, and is read first from the upper address 1 and the lower address 0 of the node address space of the transmitting device 1 using a block read transaction. Read the first 1024 bytes of data of the file. D (1: 0,1024) 3105 indicates a read response from the transmitting device 1 to the receiving device 2, in response to a 1024-byte read request from the receiving device 2 to the upper address 1 and the lower address 0 of the node address space. , The transmitting device returns the first 1024 bytes of data of the file.
[0209]
The subsequent R (1: 1024, 1024) 3106 also indicates a read request from the receiving device 2 to the transmitting device 1, and uses a block read transaction from the upper address 1 and the lower address 1024 of the node address space of the transmitting device 1. The next 1024-byte data of the file read earlier is read. D (1: 1024,1024) 3107 indicates a read response from the transmitting device 1 to the receiving device 2, in response to a 1024-byte read request from the receiving device 2 to the upper address 1 and the lower address 1024 of the node address space. , The transmitting device returns the next 1024-byte data.
[0210]
Here, the transmission device 1 reads the next 2048 bytes of the 3072 bytes from the beginning of the file, and sets the upper address 1, the lower address 2048, and the window size 3072 bytes of the node address space of the transmission device 1 to be readable. The data window is updated (TX13b). N (1: 2048, 3072) 3108 indicates a window notification from the transmitting device 1 to the receiving device 2, and the upper address 1, the lower address 2048, and the window size 3072 bytes of the node address space of the transmitting device 1 can be read. Is transmitted to the control window of the receiving device 2 using a block write transaction (TX12a). When receiving the window notification, the receiving device 2 makes a state transition to RX13 (RX14b), and when detecting the updated data window of the transmitting device 1, makes a transition to RX14 (RX13a).
[0211]
R (1: 2048,1024) 3109, R (1: 3072,1024) 3111, R (1: 4096,1024) 3113 indicate a read request from the receiving device 2 to the transmitting device 1, and D (1: 2048, 1024) 1024) 3110, D (1: 3072, 1024) 3112, and D (1: 4096, 1024) 3114 indicate a read response from the transmitting device 1 to the receiving device 2. The transmitting device 1 completes the transmission of 3072 bytes of the data window and transits to TX12 (TX14a), and the receiving device 2 completes the reception of 3072 bytes and transits to RX12 (RX14a).
[0212]
The transmitting device 1 reads the next 3072 bytes from the file, sets the upper address 1, the lower address 5120, and the window size 3072 bytes of the node address space of the transmitting device 1 to be readable and prepares for transmission.
[0213]
Next, N (1: 5120,3072) 3115 indicates a window notification from the transmitting device 1 to the receiving device 2, and the upper address 1, the lower address 5120, and the window size 3072 bytes of the node address space of the transmitting device 1 can be read. Is transmitted to the control window of the receiving device 2 using a block write transaction (TX12a). When receiving the window notification, the receiving device 2 makes a state transition to RX13 (RX12a), and when detecting the updated data window of the transmitting device 1, makes a transition to RX14 (RX13a).
[0214]
Thereafter, the transmitting device 1 and the receiving device 2 repeat the above processing, and from R (1: 5120,1024) 3116 and D (1: 5120,1024) 3117 to the last R (1: n−r, r) 3118. , D (1: n−r, r) 3119. Thereafter, the transmitting device 1 transmits the connection request T (0: 0,0) to the control window of the receiving device 2 using a block write transaction, and returns to the initial state TX10 (TX12b). When receiving the connection request T (0: 0,0) 3120, the receiving device 2 processes the received data, ends the receiving process, and returns to the initial state RX10 (RX12b).
[0215]
As described above, the receiving device 2 can transfer the file of the specified size by reading the data of the specified size from the specified address in the node address space of the transmitting device 1.
[0216]
That is, the transmitting device first issues a connection request to the receiving device prior to data transmission, and attempts to establish a connection. When receiving the connection request, the receiving device notifies connection permission. This establishes a connection. The transmitting device first notifies the receiving device of the address and size of the transmission data through the connection, and the receiving device reads the transmission data from the notified memory space by reading the transmission data in all or appropriate segments. Receive. This segment may be determined according to, for example, a receiving memory size that can be prepared by the receiving device, or an appropriate size may be determined in advance, and data may be read by the size regardless of the size of the receiving memory.
[0219]
As a result, a large amount of data can be transmitted using a memory that can be secured by the receiving side for data reception.
[0218]
The receiving side can proceed with data transmission under its initiative, and the memory space prepared by the transmitting side can be dynamically changed while transmitting data. The memory space secured according to the above can be used efficiently.
[0219]
Further, at the time of transmission, it is not necessary for the receiving side to collectively read all the data prepared by the transmitting side. The receiving side can control the data flow by reading out the data in an appropriate size.
[0220]
In the 1394 network, the nodes are assumed to be various devices such as home appliances. Such devices do not always have sufficient data processing capabilities. In the present embodiment, even in such a case, the receiving device can take the initiative based on the window notification and control the bandwidth of the connection set between the transmitting device and the receiving device.
[0221]
As described above, according to the present embodiment, the flow control is simplified by notifying the area for the data transfer, and the address of the transfer data and the address of the node address space are made to correspond one-to-one, so that the transmission Facilitates data division and data reconstruction after reception, and enables data transfer according to the processing capacity of devices by moving the data transfer area according to the resource status for transfer. , A simple data transfer device can be provided.
[0222]
The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but can be applied to a device including one device (for example, a copier, a facsimile machine, etc.). May be applied.
[0223]
Further, an object of the present invention is to supply a storage medium (or a recording medium) recording software program codes for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or a CPU or a CPU) of the system or the apparatus. (MPU) reads and executes the program code stored in the storage medium.
[0224]
In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the program code itself and the storage medium storing the program code constitute the present invention.
[0225]
When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. This also includes a case where some or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.
[0226]
Further, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function of the program is performed based on the instruction of the program code. This includes the case where the CPU provided in the expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.
[0227]
【The invention's effect】
As described above, according to the present invention, the flow control is simplified by notifying the area for data transfer secured on the node address space of the memory map bus.
[0228]
Further, by associating the address of the transfer data with the address of the node address space on a one-to-one basis, data division at the time of transmission and data reconstruction after reception are facilitated.
[0229]
Furthermore, by moving the area for data transfer according to the resource status for transfer, data transfer according to the processing capacity of the device has been made possible.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of first and second embodiments.
FIG. 2 is a diagram showing a configuration of a 1394 serial bus network.
FIG. 3 is a diagram showing components of a 1394 serial bus of the present invention.
FIG. 4 is a diagram showing services that can be provided by a link layer of a 1394 serial bus according to the present invention.
FIG. 5 is a diagram showing services that can be provided by a transaction layer of a 1394 serial bus according to the present invention.
FIG. 6 is a diagram illustrating an address space in a 1394 interface.
FIG. 7 is a diagram showing addresses and functions of information stored in a CSR core register in the 1394 interface.
FIG. 8 is a diagram showing addresses and functions of information stored in a serial bus register in the 1394 interface.
FIG. 9 is a diagram showing a minimum format Configuration ROM in the 1394 interface.
FIG. 10 is a diagram illustrating a general configuration ROM in a 1394 interface.
FIG. 11 is a diagram showing addresses and functions of information stored in a serial bus device register in the 1394 interface.
FIG. 12 is a sectional view of a communication cable conforming to the IEEE 1394 standard.
FIG. 13 is a diagram illustrating a DS-Link coding scheme.
FIG.
FIG.
FIG. 16 is a diagram showing a basic sequence from a start of a bus reset to a process of assigning a node ID.
FIG. 17 is a flowchart illustrating in detail a process of step S1505 (ie, a process of automatically assigning a node ID of each node) illustrated in FIG. 15;
FIG. 18 is a diagram showing a configuration of a self ID packet in the 1394 interface.
FIG. 19 is a diagram illustrating arbitration in a 1394 network.
FIG. 20 is a diagram illustrating a case where the isochronous transfer mode and the asynchronous transfer mode are mixed in one communication cycle.
FIG. 21 is a diagram showing a format of a communication packet transferred based on an isochronous transfer mode.
FIG. 22 is a diagram showing a packet format of asynchronous transfer according to the present invention.
FIG. 23 is a diagram illustrating a node address space according to the first and second embodiments.
FIG. 24 is a diagram illustrating a data format of a control window according to the first and second embodiments.
FIG. 25 is a diagram illustrating command values and meanings according to the first and second embodiments.
FIG. 26 is a state transition diagram of the transmission device 1 according to the first embodiment.
FIG. 27 is a state transition diagram of the receiving device 2 according to the first embodiment.
FIG. 28 is a diagram illustrating an example of a communication flow according to the first embodiment.
FIG. 29 is a state transition diagram of the transmission device 1 according to the second embodiment.
FIG. 30 is a state transition diagram of the receiving device 2 according to the second embodiment.
FIG. 31 is a diagram illustrating an example of a communication flow according to the second embodiment.
[Explanation of symbols]
1 transmitting device
11 System bus
12 CPU
13 ROM
14 RAM
15 External devices
16 IEEE 1394 interface
2 Receiver
21 System bus
22 CPU
23 ROM
24 RAM
25 External device
26 IEEE 1394 interface
3 IEEE1394 cable

Claims (18)

A data transfer system having a first device and a second device connected by a memory map bus,
The first device comprises:
Arranging means for arranging a data area variably in address and size in a node address space of the memory map bus;
Notifying means for notifying the second device of the address and size information of the area arranged by the arranging means,
The second device performs data transfer with the first device via the data area in the first device based on the address and size information notified by the notification means. Characterized data transfer system. The first device arranges a writable data area by the arranging means, notifies the address and size information to the second device by the notifying means, and the second device notifies the second device by the notifying means. The data transfer from the second device to the first device is performed by writing data to the data area via the memory map bus based on the notified address and size information. The data transfer system according to claim 1. The second device divides data so that an address thereof corresponds to an address of the node address space and writes the divided data into the data area, and the first device writes the data written into the data area. 3. The data transfer system according to claim 2, wherein the address is reconfigured so as to correspond to an address in the node address space. The first device writes data in the data area, and notifies the second device of the address and size information by the notifying unit, and the second device notifies the address notified by the notifying unit of the address. 2. The data transfer from the first device to the second device by reading data from the data area via the memory map bus based on the size information and the size information. Data transfer system as described. The first device divides data so that its address corresponds to an address in the node address space and writes the divided data into the data area, and the second device writes the data written into the data area, 5. The data transfer system according to claim 4, wherein the address is reconfigured so as to correspond to an address in the node address space. The first device further includes a release unit that releases the data area arranged by the arrangement unit, and moves the data area in the node address space by repeating the arrangement by the arrangement unit and the release by the release unit. The data transfer system according to any one of claims 1 to 5, wherein: 2. The data transfer system according to claim 1, wherein the memory map bus is an IEEE 1394 bus, and the notification by the notification unit and the data transfer are performed by a transaction provided by a transaction layer of an IEEE 1394 interface. A receiving device connected to the transmitting device by a memory map bus,
Arranging means for arranging a writable area by the transmitting device variably in address and size in a node address space of a memory map bus;
Notifying means for notifying the transmitting device of the address and size information of the area,
Receiving means for receiving data written in the area by the transmitting device. A transmitting device connected to the receiving device by a memory map bus,
Receiving means for receiving address and size information from the receiving device;
A transmitting unit for transmitting data by writing data in an area specified by the address and size information received by the receiving unit. A transmitting device connected to the receiving device by a memory map bus,
Means for arranging a writable area by the transmitting device variably in address and size in a node address space of a memory map bus, and writing transmission data in the area;
Notifying means for notifying the receiving device of the address and size information of the area,
Transmitting means for transmitting data written by the transmitting device to the area. A receiving device connected to the transmitting device by a memory map bus,
First receiving means for receiving address and size information from the transmitting device;
A receiving apparatus comprising: a second receiving unit that receives data by reading data from an area specified by the address and size information received by the receiving unit. A method for controlling a receiving device connected to a transmitting device by a memory map bus,
An arranging step of arranging a writable area by the transmitting device at an address and a size variable in a node address space of a memory map bus;
A notifying step of notifying the address and size information of the area to the transmitting device,
A receiving step of receiving data written in the area by the transmitting device. A method for controlling a transmitting device connected to a receiving device by a memory map bus,
A receiving step of receiving address and size information from the receiving device,
A control unit for transmitting data by writing data in an area specified by the address and size information received in the receiving step. A method for controlling a transmitting device connected to a receiving device by a memory map bus,
Arranging a writable area by the transmitting device at an address and a size variable in a node address space of a memory map bus, and writing transmission data to the area;
Notification step of notifying the address and size information of the area to the receiving device,
Transmitting the data written by the transmitting device to the area. A control process of the receiving device connected to the transmitting device by a memory map bus,
A first receiving step of receiving address and size information from the transmitting device;
A second receiving step of receiving data by reading data from an area specified by the address and size information received in the receiving step. A computer program for realizing a control method of a receiving device according to claim 12 by a computer. A computer program for realizing a control method of a transmission device according to claim 13 by a computer. A computer-readable recording medium on which the computer program according to claim 16 is recorded.

Images