JPH10290247A - Data communication method, apparatus, system, and storage medium - Google Patents

Abstract

(57) Abstract: Provided is a data communication method in which a communication protocol for performing data communication between a host device and a target device is not limited by the target device. SOLUTION: In response to a request from a host device using an initial protocol, capability information including information indicating a plurality of communication protocols is returned, and a communication protocol specified by the host device is set based on the capability information, According to the communication protocol, data (print data) from the host device is received.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a data communication method,
The present invention relates to a data communication device, a data communication system, and a computer-readable storage medium storing processing steps for executing the data communication device. In particular, a communication protocol for performing data communication between a host device and a target device includes The present invention relates to a data communication method, a data communication device, a data communication system, and a storage medium that are not limited by devices.

[0002]

2. Description of the Related Art Conventionally, various types of systems have been known as systems for sending data to a printer via a general-purpose interface. For example, SCSI (Sm
2. Description of the Related Art A technique of outputting data from a computer to a printer using a de facto standard interface, which has been widely used in general, such as All Computer System Interface) or Centronics, is known.

[0003]

However, a printer protocol for transferring print data to a printer using these interfaces is limited to a printer manufacturer-specific one and lacks expandability.
The problem has arisen. In particular, when print data is transferred using an interface for connecting various types of devices, for example, a serial interface such as IEEE1394, the problem of lack of expandability is a major problem to be solved. In addition, how to quickly set a protocol used for transferring the print data is a major issue.

Accordingly, the present invention has been made to eliminate the above-mentioned disadvantages, and a communication protocol for performing data communication between a host device and a target device is not limited by the target device. Data communication method, data communication device, data communication system,
And a storage medium. Another object of the present invention is to provide a suitable data communication method, data communication device, data communication system, and storage medium using a serial interface such as the IEEE1394 standard. Further, the present invention provides a data communication method, a data communication device, a data communication system, and a storage medium suitable for transferring image data directly from a host device to a target device without going through a host computer. Aim.

[0005]

For such a purpose,
A first invention is a data communication method for performing data communication using a serial bus, comprising: an information acquisition step of acquiring capability information of a target device by communication using an initial protocol; and a capability acquired by the information acquisition step. A setting step of setting a communication protocol usable for data communication to the target device based on the information; and a communication step of performing data communication with the target device based on the communication protocol set in the setting step. And characterized in that:

According to a second aspect, in the first aspect,
The target device is capable of supporting a plurality of communication protocols, and the capability information includes information indicating the plurality of communication protocols.

[0007] A third invention is the above-mentioned first invention, wherein:
The target device includes a printer, and the data communicated by the communication protocol includes image data.

[0008] In a fourth aspect based on the first aspect,
The target device includes an inkjet printer, and the plurality of communication protocols supported by the target device include those adapted for image formation by the inkjet printer.

A fifth aspect of the present invention is a data communication method for performing data communication using a serial bus, comprising: an information returning step of returning capability information in response to a request from a host device using an initial protocol; A setting step of setting a communication protocol to be used for data communication according to an instruction from the host device based on the capability information returned by the host device, based on the communication protocol set by the setting step, And a communication step for performing data communication.

In a sixth aspect based on the fifth aspect,
A plurality of communication protocols can be supported, and the capability information includes information indicating the plurality of communication protocols.

In a seventh aspect based on the fifth aspect,
The data communicated by the communication protocol includes image data.

According to an eighth aspect, in the sixth aspect,
The plurality of communication protocols include one adapted for image formation by an inkjet printer.

In a ninth aspect based on the first or fifth aspect, the data communicated by the communication protocol is:
It is characterized by including image data obtained by imaging.

According to a tenth aspect, in the first or fifth aspect, the serial bus includes a bus conforming to or conforming to the IEEE 1394 standard.

In an eleventh aspect based on the first or fifth aspect, the serial bus includes a bus conforming to or conforming to the IEEE 1394 standard, and the capability information includes
The setting step includes information stored in a CSR register of an address space in the EEE1394 standard, and the setting step includes a step of setting the communication protocol by the CSR register.

In a twelfth aspect based on the first or fifth aspect, the serial bus is a Universal Serial Bus.
It is characterized by including a bus conforming to or conforming to the serial bus standard.

According to a thirteenth aspect, in the first or fifth aspect, the initial protocol includes a protocol executed in a layer higher than the data link layer of the OSI model.

A fourteenth invention is a data communication method for performing data communication using a serial bus, wherein the receiving step of receiving a connection request from a host device and the host device do not support a predetermined protocol. When recognizing that, a setting step of setting a communication protocol used for data communication, a trial step of trying to communicate with the host device according to the communication protocol set in the setting step, and the host device by the trial step A communication step of performing data communication with the host device using the communication protocol set in the setting step when communication with the host device is established.

A fifteenth aspect of the present invention is a data communication apparatus for performing data communication using a serial bus, comprising: a communication means capable of supporting an initial protocol and a plurality of communication protocols for data communication; Storage means in which capability information including information indicating the information is stored, and setting means for setting a communication protocol of the communication means, wherein the communication means, based on a request from a host device using the initial protocol, The capability information stored in the storage unit is sent to the host device, and the setting unit sets a communication protocol of the communication unit according to the instruction of the host device using the initial protocol.

According to a sixteenth aspect, there is provided a data communication apparatus for performing data communication using a serial bus, comprising: a communication unit capable of supporting an initial protocol and a plurality of communication protocols for data communication; Control means for controlling data communication, the control means, when the communication means recognizes that the host device does not support the initial protocol by a connection request received from the host device, the communication means A predetermined communication protocol is set, communication with the host device is attempted using the communication protocol, and when communication with the host device is established, data communication is performed with the host device using the set communication protocol. Control as described above.

A seventeenth invention is a data communication system for performing data communication using a serial bus.
14. The at least one host device, the at least one host device, and the at least one target device, comprising at least one target device, the at least one host device, and the at least one target device according to a data communication method according to any of Data communication is performed with one target device.

An eighteenth invention is a data communication system including first and second devices and a serial bus defining a predetermined address space for each of the devices. The first device includes first protocol capability storage means for storing information independently presenting a plurality of data transport protocols which can be supported and present in an address space defined by a bus, and wherein the second device includes: A second confirmation means for confirming the contents of the first protocol capability storage means by designating and reading an address space defined by the serial bus; and a contents of the first protocol capability storage means. Second determining means for determining a data transport protocol, wherein the second confirming means comprises: Prior to the determination in the second determination means, characterized in that to check a plurality of compatible data transport protocol.

In a nineteenth aspect based on the eighteenth aspect, the first device is located in an address space defined by the serial bus and stores lock information for storing information indicating a resource occupation state. Is further included.

According to a twentieth aspect, in the eighteenth aspect, the first device is a lock storage means which is present in an address space defined by the serial bus and stores information indicating a resource occupation state. The second device further comprises: a lock content confirmation unit that confirms the content of the lock storage unit by a read or lock transaction that specifies an address space defined by the serial bus; and a lock content confirmation unit. Determining means for determining whether or not the first device is occupied by the confirmation result.

According to a twenty-first aspect, in the eighteenth aspect, the data transport protocol includes a printer protocol.

According to a twenty-second aspect, in the twenty-first aspect, the printer protocol includes a protocol for transferring data to be printed.

According to a twenty-third aspect, in the eighteenth aspect, the second device includes a device for outputting image data.

According to a twenty-fourth invention, in the twenty-third invention, the second device is a computer, a digital camera, a scanner, a DVD, a Set-top-Box, a digital television, a conference camera, a digital video, and And a device including at least one of the multifunction peripherals.

According to a twenty-fifth aspect, in the eighteenth aspect, the first device further includes protocol storage means for storing the data transport protocol determined by the second determination means. I do.

According to a twenty-sixth aspect, in the eighteenth aspect, the serial bus includes a bus conforming to or conforming to the IEEE 1394 standard.

According to a twenty-seventh aspect, in the eighteenth aspect, the serial bus includes a bus for modulating and transferring data by a DS-link system.

According to a twenty-eighth aspect, in the eighteenth aspect, the second confirming means stores the contents of the first protocol capability storing means in a read transaction for designating an address space defined by the serial bus. It is characterized by confirmation by an action.

According to a twenty-ninth aspect, in the twenty-eighth aspect, the read transaction is executed in a layer lower than a transport protocol layer of the serial bus.

According to a thirtieth aspect, in the eighteenth aspect, the first device includes a device to which image data is input.

According to a thirty-first aspect, in the thirtieth aspect, the first device includes at least one of a monitor, a computer, an external storage device, a set-top-box, a printer, and a multifunction peripheral including these. It is a device.

According to a thirty-second aspect, in the eighteenth aspect, in the second device, the second device exists in an address space defined by the serial bus, and independently supports a plurality of data transport protocols that can be supported. And a second protocol capability storage unit for storing information indicated by the protocol capability.

In a thirty-third aspect, in the eighteenth aspect, the first device confirms the contents of the protocol capability storage means by designating an address space defined by the serial bus. First
And first determining means for determining a data transport protocol based on the contents of the protocol capability storing means, wherein the first determining means determines the data transport protocol by the first determining means. Prior to this, a plurality of compatible data transport protocols are confirmed.

A thirty-fourth invention is at least one of the plurality of devices for configuring a data communication system including a plurality of devices and a serial bus defining a predetermined address space for each device. A data communication device, wherein information independently indicating a plurality of compatible data transport protocols stored in an address space defined by the serial bus is specified, and an address space defined by the serial bus is designated. And confirmation means for confirming by reading, and determining means for determining a data transport protocol based on the confirmation result in the confirmation means, wherein the confirmation means,
Prior to the determination by the determining means, a plurality of compatible data transport protocols are confirmed.

A thirty-fifth aspect of the present invention is the first device for configuring the data communication system according to any one of claims 18 to 33.

According to a thirty-sixth aspect, the present invention is a second device for constituting the data communication system according to any one of claims 18 to 33.

A thirty-seventh invention is a data communication method for performing data communication between a first device and a second device via a serial bus defining a predetermined address space for each device. Reading information stored in a protocol capability register existing in an address space defined by the serial bus, in which information indicating a specific data transport protocol is stored, by designating the address space defined by the serial bus; And a determining step of determining a data transport protocol based on the result of the checking in the checking step, wherein the checking step is performed before the determination by the determining step. Including the step of verifying the transport protocol. And butterflies.

A thirty-eighth invention is a data communication method for a device connected to a serial bus which defines a predetermined address space for each device, wherein information indicating a data transport protocol which can be supported is stored in the serial bus. And reading from a protocol capability register existing in an address space defined by

A thirty-ninth aspect of the present invention is a data communication method for a device connected to a serial bus which defines a predetermined address space for each device, wherein the protocol capability register of another device connected to the serial bus is provided. And a determining step of determining a data transport protocol based on the result of the confirmation in the confirmation step. The checking step includes a step of checking a plurality of compatible data transport protocols prior to the determination by the determining step.

A fortieth aspect of the present invention relates to a first device and a second device.
A computer-readable storage medium storing processing steps for performing data communication in a system including a device and a serial bus defining a predetermined address space for each device, the processing step comprising: Specifies the storage contents of the protocol capability register existing on the address space defined by the serial bus, in which information indicating a data transport protocol that can be supported is stored, and specifies the address space defined by the serial bus. And a determining step of determining a data transport protocol based on the result of the checking in the checking step, wherein the checking step includes a plurality of steps prior to the determination by the determining step. Compatible data transport protocols Characterized in that it comprises a step of checking.

[0045] A forty-first invention is a storage medium in which computer-readable processing steps for performing data communication of devices connected to a serial bus that define a predetermined address space for each device are stored. The processing step includes a step of reading information indicating a compatible data transport protocol from a protocol capability register existing in an address space defined by the serial bus.

A forty-second invention is a storage medium in which processing steps for performing data communication of a device connected to a serial bus defining a predetermined address space for each device are readable by a computer. The processing step includes a confirmation step of confirming contents stored in a protocol capability register of another device connected to the serial bus by designating and reading an address space defined by the serial bus. Deciding a data transport protocol based on the confirmation result in the confirming step, wherein the confirming step confirms a plurality of available data transport protocols prior to the decision by the deciding step. It is characterized by including a step.

A forty-third invention is a storage medium in which processing steps for performing data communication using a serial bus are stored so as to be readable by a computer, and the processing steps are described in claims 1 to 14 and 37. 39. A data communication method according to any one of the above-described items,

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the first and second embodiments described below, as a digital interface for connecting each device, for example, IEEE 1394-1995 (High P
(hereinafter, simply referred to as "1394 serial bus"), the outline of the 1394 serial bus will be described first.

[Outline of 1394 Serial Bus]

Digital Video Cam Recorder for Consumers (VC
R) and digital video disc (DVD) players, real-time and high-data-content data such as video data and audio data (hereinafter collectively referred to as "AV data") are transferred. Need to be done. In order to transfer AV data to a personal computer (PC) or other digital devices in real time and capture it, an interface capable of high-speed data transfer is required. An interface developed from such a viewpoint is the 1394 serial bus.

FIG. 1 shows an example of a network system configured using a 1394 serial bus.

This system comprises devices A, B, C, D,
E, F, G, and H, between A and B, A to C
, B-D, D-E, C-F, C-G, and C
−H are connected by a twisted pair cable for 1394 serial bus. An example of these devices A to H is a host computer device such as a personal computer, and a computer peripheral device. Computer peripherals include digital VCRs, DVD players, digital still cameras, storage devices using media such as hard disks and optical disks, CRT and LCD monitors, tuners, image scanners, film scanners, printers, MODEMs, and terminal adapters (TA). And all computer peripherals.

The connection between the devices can be a mixture of the daisy chain method and the node branch method, and a highly flexible connection can be made. Also, each device has an ID, and by recognizing the ID with each other, the 1394
One network is configured in a range connected by a serial bus. For example, each device has one
By simply daisy-chaining with a 394 serial bus cable, each device plays a role of relay, so that one network can be configured as a whole.

The 1394 serial bus is provided by Plug and
It supports Play function and has a function to automatically recognize the device just by connecting the cable to the device and recognize the connection status.

In the system shown in FIG.
When a device is removed from the network or newly added, for example, the bus is automatically reset (the configuration information of the existing network is reset) to reconstruct a new network. With this function, the configuration of the network at that time can be constantly set and recognized.

The data transfer speed of the 1394 serial bus is defined as 100/200/400 Mbps, and compatibility is maintained by supporting devices having higher transfer speeds to support lower transfer speeds. .

The data transfer mode includes an asynchronous transfer mode (ATM) for transferring asynchronous data such as a control signal, and an isochronous transfer mode for transferring synchronous data of real-time AV data. The asynchronous data and the synchronous data are stored in each cycle (typically 125 μS
/ Cycle), the transfer of the cycle start packet (CSP) indicating the start of the cycle is followed by the transfer of the synchronous data, and the transfer is performed in a mixed manner within the cycle.

FIG. 2 is a diagram showing components of the 1394 serial bus.

The 1394 serial bus has a layer structure. As shown in FIG. 2 above, there is a connector port 810 to which a connector at the end of a 1394 serial bus cable 813 is connected. Connector port 810
There are a physical layer 811 and a link layer 812 that are configured by the hardware unit 800 at a higher level.

The hardware section 800 is composed of an interface chip, of which a physical layer 811 performs coding, connection-related control, and the like.
The link layer 812 performs packet transfer, cycle time control, and the like.

The transaction layer 814 of the firmware unit 801 manages data to be transferred (transacted), and performs Read, Write, Loc
Issue k instructions. The management layer 815 of the firmware unit 801 manages the connection status and ID of each device connected to the 1394 serial bus, and manages the configuration of the network.

The above hardware and firmware are the substantial configuration of the 1394 serial bus.

The application layer 816 of the software unit 802 differs depending on the software used, and how data is transferred on the interface is defined by a protocol such as a printer or an AV / C protocol. .

FIG. 3 is a diagram showing an address space in the 1394 serial bus.

Each device (node) connected to the 1394 serial bus always has a 64-bit address unique to the node. This address is stored in the memory of the device, and by constantly recognizing the node address of itself or the other party, it is possible to perform data communication specifying the other party.

Addressing of the 1394 serial bus is based on the IEEE 1212 standard, and the first 10 bits are used to specify the bus number.
The next 6 bits are used for specifying the node ID. The remaining 48 bits become the address width given to the device, and can be used as a unique address space. Last 28
The bit is a data area unique to the device, and stores identification of each device, designation information of use conditions, and the like.

The above is the outline of the 1394 serial bus. Next, the features of the 1394 serial bus will be described in more detail.

[Electrical Specifications of 1394 Serial Bus]

FIG. 4 is a diagram showing a cross section of a cable for a 1394 serial bus. The 1394 serial bus cable is provided with a power supply line in addition to the two twisted pair signal lines. As a result, power can be supplied to a device having no power supply, a device whose voltage has been reduced due to a failure, or the like. The voltage of the DC power supplied by the power supply line is specified to be 8 to 40 V, and the current is specified to be a maximum current of 1.5 A.

In a standard called a DV cable, the cable is composed of four wires without a power supply line.

[DS-Link system]

FIG. 5 shows a DS-Link (Data / Strob) of the data transfer system adopted in the 1394 serial bus.
FIG. 3 is a diagram for explaining an eLink) method. DS-Lin
The k method is suitable for high-speed serial data communication and requires two sets of signal lines. That is, a data signal is transmitted by one of the two pairs and a strobe signal is transmitted by the other pair. The receiving side has a feature that a clock can be generated by taking an exclusive OR of this data signal and the strobe signal. For this reason,
Since it is not necessary to mix a clock signal into a data signal using the DS-Link method, transfer efficiency is higher than other serial data transfer methods, and a clock signal can be generated, so that a phase locked loop (PLL) circuit is not required. Therefore, the circuit scale of the controller LSI can be reduced accordingly, and since there is no need to send information indicating the idle state when there is no data to be transferred, the transceiver circuit of each device is set to the sleep state. Power consumption can be reduced.

[Bus Reset Sequence]

Each device (node) connected to the 1394 serial bus is given a node ID and recognized as a node constituting a network. For example, when the number of nodes increases or decreases due to connection / disconnection of network devices, power ON / OFF, and the like, that is, there is a change in the network configuration, and when it is necessary to recognize a new network configuration, each node that has detected the change sends a A bus reset signal is sent up to enter a mode for recognizing a new network configuration. Detection of this change in network configuration
This is done by detecting a change in the bias voltage at connector port 810. When a bus reset signal is transmitted from a certain node, the physical layer 811 of each node transmits the bus reset signal to the link layer 812 upon receiving the bus reset signal, and transmits the bus reset signal to another node. I do. After all the nodes finally receive the bus reset signal, the bus reset sequence is started.

The bus reset sequence is started when a cable is connected or disconnected, or when the hardware detects a network error or the like, and directly issues a command to the physical layer 811 such as host control using a protocol. It is also activated by giving. When the bus reset sequence is activated, the data transfer
The bus is temporarily suspended, waited during the bus reset, and resumed under the new network configuration after the bus reset is completed.

[Node ID Determination Sequence]

After the bus reset, each node starts an operation of giving an ID to each node in order to construct a new network configuration. At this time, from the bus reset to the node I
A general sequence up to the determination of D will be described with reference to the flowcharts shown in FIGS.

FIG. 6 is a flowchart showing a series of sequences from the generation of the bus reset signal to the determination of the node ID and the start of data transfer.

Each node constantly monitors the bus reset signal in step S101. When the bus reset signal is generated, the process proceeds to step S102, where the nodes are directly connected to each other to obtain a new network configuration in a state where the network configuration is reset. A parent-child relationship is declared between each node. Then, according to the determination in step S103,
Until it is determined that the parent-child relationship has been determined between all nodes,
Step S102 is repeated. When the parent-child relationship is determined, the process proceeds to step S104, and a route is determined.

At step S105, a node ID setting operation for giving an ID to each node is performed. Node IDs are set in the order of predetermined nodes from the root, and step S1
In step 06, it is determined that IDs have been assigned to all nodes, and step S105 is repeated. When the setting of the node ID is completed, the new network configuration has been recognized by all the nodes, so that data transfer between the nodes can be performed.
7, the data transfer is started, and the sequence returns to step S101, and the occurrence of the bus reset signal is monitored again.

In FIG. 7, the route is determined from the monitoring of the bus reset signal (step S101) (step S104).
FIG. 8 is a flowchart showing the details up to FIG.
It is a flowchart which shows the detail of ID setting (step S105, S106).

In FIG. 7, the generation of the bus reset signal is monitored in step S201, and when the bus reset signal is generated, the network configuration is reset once.

In step S202, as the first stage of the operation of re-recognizing the reset network configuration, each device resets the flag FL with data indicating a leaf (node). In step S203, each device checks the number of ports, that is, the number of other nodes connected to itself.
In order to start the declaration of the parent-child relationship, the number of undefined (parent-child relationship has not been determined) ports is examined. Here, the number of undefined ports is equal to the number of ports immediately after the bus reset, but as the parent-child relationship is determined, the number of undefined ports detected in step S204 decreases.

Immediately after the bus reset, the declaration of the parent-child relationship can be made only on actual leaves. Whether it is a leaf or not can be known from the result of checking the number of ports in step S203. That is, if the number of ports is "1", it is a leaf. In step S205, the leaf declares a parent-child relationship with respect to the connection partner node "I am a child and the other is a parent."
And terminate the operation.

On the other hand, the node whose number of ports is “2” or more in step S 203, that is, the branch is “undefined port number> 1” immediately after the bus reset, so the process proceeds to step S 206 to branch to the flag FL. Is set, and in step S207, the process waits for declaration of a parent-child relationship from another node.

The parent-child relationship is declared from another node, and the branch that has received the declaration returns to step S204 to check the number of undefined ports. If the number of undefined ports is "1", the remaining ports are determined. In step S205, a parent-child relationship of "I am a child and the other party is a parent" can be declared for the other nodes connected to the. If the number of undefined ports is “2” or more, the branch is executed again in step S207.
Then, it waits for another node to declare the "parent-child relationship" again.

If the number of undefined ports of any one branch (or, in exceptional cases, a leaf that could not be operated quickly despite being able to make a child declaration) becomes “0”, the parent-child relationship declaration of the entire network is made. Has ended, and the only node whose undefined port number has become “0”, that is, the node that has been determined to be the parent of all nodes, is determined in step S208.
In step S209, data indicating a route is set in the flag FL, and the flag FL is recognized as a route.

Thus, the procedure from the bus reset to the declaration of the parent-child relationship between the nodes in the network is completed.

Next, a procedure for giving an ID to each node will be described. First, the ID can be set.
It is a leaf. Then, an ID is set from a young number (node number: 0) in the order of leaf → branch → root.

In FIG. 8, in step S301,
Based on the data set in the flag FL, the type of the node,
That is, the process branches to a process corresponding to a leaf, a branch, and a route.

First, in the case of a leaf, step S302
Then, after setting the number (natural number) of leaves existing in the network to the variable N, in step S303, the leaf requests a node number from the root. If there are a plurality of such requests, the root performs arbitration in step S304, assigns a node number to one node in step S305, and notifies another node of a result indicating that acquisition of the node number has failed.

If the node number could not be obtained by the determination in step S306, the leaf returns to step S303.
Repeats the request for the node number.

On the other hand, the leaf from which the node number can be obtained is
In step S307, all nodes are notified by broadcasting ID information including the acquired node number. When the broadcasting of the ID information ends, the variable N representing the number of leaves is decremented in step S308. Then, according to the determination in step S309, the variable N
From step S303 to step S
After the procedure of step 308 is repeated and the ID information of all leaves is broadcast, the process proceeds to step S310,
Move on to branch ID setting.

The setting of the branch ID is performed in substantially the same manner as that of the leaf.

First, in step S310, the number (natural number) of branches existing in the network is set as a variable M, and then in step S311, the branch requests a node number from the root. In response to this request, the root performs arbitration in step S312, and in step S313 gives a certain branch a smaller number following the leaf, and notifies a branch that could not acquire the node number a result indicating acquisition failure. I do.

The branch that has determined that the acquisition of the node number has failed by the determination in step S314 repeats the request for the node number again in step S311.

On the other hand, the branch from which the node number has been obtained is determined in step S315 by the I branch including the obtained node number.
All nodes are notified by broadcasting D information.

When the broadcasting of the ID information ends,
In step S316, the variable M indicating the number of branches is decremented by. Then, the procedure from step S311 to step S316 is repeated until the variable M becomes “0” based on the determination in step S317, and after the ID information of all the branches is broadcast, step S3
Then, the process proceeds to step 18 where the route ID is set.

When the process is completed so far, since only the root node has not acquired the ID information in the end, step S
At 318, the lowest number not assigned to another node is set as its own node number, and at step S319, the ID information of the route is broadcast.

Thus, the procedure until all node IDs are set is completed.

Next, a specific procedure of a node ID determination sequence will be described with reference to a network example shown in FIG.

In the network shown in FIG. 9, the nodes A and C are directly connected below the node B, which is the root, and the node D is directly connected below the node C.
Has a hierarchical structure in which nodes E and F are directly connected. The procedure for determining the hierarchical structure, the root node, and the node ID is as follows.

After the occurrence of the bus reset, a parent-child relationship is declared between the directly connected ports of each node in order to recognize the connection status of each node. Here, the parent and child means that the upper level of the hierarchical structure is “parent” and the lower level is “child”. In FIG. 9, it is the node A that first declared the parent-child relationship after the bus reset. As described above, the declaration of the parent-child relationship can be started from a node (leaf) to which only one port is connected. This means that if the number of ports is "1", the end of the network,
In other words, it is recognized that the node is a leaf, and the parent-child relationship is determined from the node that operates first among the leaves. In this way, the port of the node that has declared the parent-child relationship is set as the “child” of the two nodes connected to each other, and the node of the partner node is set as the “parent”. Thus, between nodes AB, between nodes E and D,
“Child-parent” is set between the nodes FD.

Further, the hierarchy is moved up by one, and a node having a plurality of ports, that is, a branch that has received a declaration of a parent-child relationship from another node among branches is sequentially declared a parent-child relationship with respect to an upper node. In FIG. 9, first, after the parent-child relationship between the nodes DE and DF is determined, the node D declares the parent-child relationship to the node C, and as a result, “ A child-parent relationship is set.
The node C, which has received the declaration of the parent-child relationship from the node D, declares a parent-child relationship to the node B connected to another port.
A "parent" relationship is set.

In this way, a hierarchical structure as shown in FIG. 9 is formed, and the parent node B in all finally connected ports is determined as the root. Note that there is only one route in one network configuration. Further, when the node B, which has been declared the parent-child relationship from the node A, promptly declares the parent-child relationship to another node, for example, there is a possibility that another node such as the node C becomes the root. That is, depending on the timing at which the declaration of the parent-child relationship is transmitted, there is a possibility that any node may become the root, and even if the network configuration is the same, a specific node does not always become the root.

When the route is determined, the process enters a mode for determining each node ID. All nodes have their own IDs
It has a broadcast function of notifying information to all other nodes. Note that the ID information includes a node number, information on a connected position, the number of connected ports, the number of connected ports, and information on the parent-child relationship of each port.
It is broadcast as D information.

As described above, the assignment of the node numbers is started from the leaf, and the node numbers = 0, 1,.
2,... Are assigned. Then, by broadcasting the ID information, it is recognized that the node number has been allocated. When all the leaves have acquired the node numbers, the process moves to the branch, and the node numbers following the leaves are assigned. Like the leaf, the ID information is broadcast in order from the branch to which the node number is assigned, and finally the root broadcasts its own ID information. Therefore, the root always owns the highest node number.

As described above, the ID setting for the entire hierarchical structure is completed, the network configuration is reconstructed, and the bus initialization operation is completed.

[Bus Arbitration]

The 1394 serial bus always arbitrates for the right to use the bus prior to data transfer.
Each device connected to the 1394 serial bus relays signals transferred on the network,
Since a logical bus network that transmits the same signal to all devices in the network is configured, bus arbitration is necessary to prevent packet collision. This allows only one node to transfer at a given time.

FIGS. 10A and 10B are views for explaining arbitration, and FIG.
FIG. 10 shows the operation for requesting the right to use the bus.
(B) shows an operation of permitting use of the bus.

When the bus arbitration starts, one or more nodes respectively request the right to use the bus toward the parent node. In FIG. 10A, the nodes C and F are requesting the right to use the bus.
The parent node (node A in FIG. 10A) that has received this request further requests the parent node for the right to use the bus, thereby relaying the request for the right to use the bus by the node F. This request is finally delivered to the arbitration route.

The route receiving the request for the right to use the bus determines which node is to be given the right to use the bus. This arbitration work can be performed only by the route, and the node that wins the arbitration is given a bus use permission. FIG. 10 above
(B) shows a state in which the node C is given a bus use permission and the node F request for the bus use right is rejected.

The route sends a DP (data prefix) packet to the node that has lost the bus arbitration to notify that the request for the right to use the bus has been rejected. The request for the right to use the bus of the node that has lost the bus arbitration is kept waiting until the next bus arbitration.

As described above, the node that has won the bus arbitration and obtained the bus use permission can start data transfer thereafter.

Here, a flowchart of a series of bus arbitration flows will be described with reference to FIG.

In order for a node to be able to start data transfer,
The bus must be idle. In order to recognize that the bus is in an idle state after the previous data transfer is completed, a gap length of a predetermined idle time individually set in each transfer mode (for example, By detecting the elapse of the action gap, each node determines that the bus is idle.

Each node determines in step S401 whether a predetermined gap length has been obtained according to the asynchronous data or synchronous data to be transferred. Unless the predetermined gap length is obtained, the node cannot request the right to use the bus required to start the transfer, and thus waits until the predetermined gap length is obtained.

When a predetermined gap length is obtained in step S401, each node determines whether there is data to be transferred in step S402, and if so, in step S403, sends a signal requesting the right to use the bus to the root. To send. The signal indicating the request for the right to use the bus is shown in FIG.
As shown in (a), it is finally delivered to the route while being relayed to each device in the network. Step S
If it is determined in step 402 that there is no data to be transferred, the process returns to step S401.

If at least one signal requesting the right to use the bus is received in step S404, the route proceeds to step S4.
At step 05, the number of nodes requesting the use right is checked. If it is determined in step S405 that there is only one node that has requested the right to use, the immediately subsequent bus use permission is given to that node. If there are a plurality of nodes requesting the right to use, in step S406, an arbitration operation is performed to narrow down the number of nodes to which the right to use the bus immediately after to one. This arbitration work does not always grant the use of the bus only to the same node, but equally grants the right to use the bus (fair arbitration).

The route process branches in step S407 according to one node that has won the arbitration in step S406 and another node that has lost the arbitration. If one node has won the arbitration or one node has requested the right to use the bus, a permission signal indicating permission to use the bus is sent to the node in step S408.

The node that has received the permission signal starts transferring data (packets) to be transferred immediately in step S410. In step S409, a DP (data prefix) packet indicating that the request for the right to use the bus has been rejected is sent to the node that has lost the arbitration. The process of the node that has received the DP packet returns to step S401 to request the right to use the bus again. The processing of the node that has completed the data transfer in step S410 also returns to step S401.

[Asynchronous transfer]

FIG. 12 shows a temporal transition state in the asynchronous transfer. The first sub-action gap shown in FIG. 12 indicates the idle state of the bus. When the idle time reaches a predetermined value, it is determined that the node desiring data transfer can request the right to use the bus, and bus arbitration is executed. When bus arbitration permits the use of the bus,
Next, a data transfer is packetized, and the node receiving this data, after a short gap of ack gap,
Data transfer is completed by returning a response code for acknowledgment or sending a response packet. ack
Is composed of 4 bits of information and 4 bits of a checksum, and includes information indicating a success, busy state, or pending state, and is immediately returned to the data transmission source node.

FIG. 13 is a diagram showing a packet format for asynchronous transfer. The packet has a header part in addition to the data part and the data CRC for error correction. In the header part, a destination node ID, a source node ID, a transfer data length, various codes, and the like are written. Asynchronous transfer is one-to-one communication from a self-node to a partner node. The packet sent from the transfer source node is distributed to each node in the network, but since each node ignores packets other than its own, only the node designated as the destination receives the packet.

[Isochronous transfer]

The isochronous transfer, which can be said to be the greatest feature of the 1394 serial bus, is particularly suitable for the transfer of multimedia data that requires real-time transfer of AV data and the like. While the asynchronous transfer is a one-to-one transfer, the isochronous transfer can uniformly transfer data from one transfer source node to all other nodes by a broadcast function.

FIG. 14 is a diagram showing a temporal transition state in the isochronous transfer.

The isochronous transfer is executed at regular intervals on the bus, and this time interval is called an isochronous cycle. The isochronous cycle time is 125 μS. A cycle start packet (CSP) indicates the start of each synchronization cycle and synchronizes the operation of each node. To send the CSP,
A node called a cycle master, which transmits a CSP notifying the start of this cycle after a transfer in the previous cycle is completed and a predetermined idle period (subaction gap) has passed. That is, the time interval for transmitting the CSP is 125 μS.

As shown in FIG. 14 as channels A, B, and C, a plurality of types of packets are given channel IDs in one synchronization cycle, so that the packets are distinguished and transferred. be able to. As a result, real-time transfer can be performed substantially simultaneously between a plurality of nodes, and the receiving node only needs to receive data of the channel ID desired by itself. This channel ID does not represent the address of the receiving node or the like, but is merely a logical number for data. Therefore, the transmitted packet is distributed from one source node to all other nodes, that is, broadcast.

Prior to packet transmission in isochronous transfer, bus arbitration is performed in the same manner as in asynchronous transfer. However, since it is not one-to-one communication as in asynchronous transfer, there is no acknowledgment return code acknowledgment in isochronous transfer.

In addition, the iso gap shown in FIG.
(Isochronous gap) represents an idle period necessary for recognizing that the bus is in an idle state before performing isochronous transfer. After the lapse of the predetermined idle period, arbitration of the bus with respect to the node that is to perform the isochronous transfer is performed.

FIG. 15 is a diagram showing a packet format for isochronous transfer. Each packet divided into each channel has a header portion in addition to a data portion and an error correction data CRC, and the header portion includes a transfer data length and a channel number as shown in FIG. . , Other codes and header CR for error correction
C and the like are written.

[Bus cycle]

Actually, in the 1394 serial bus, isochronous transfer and asynchronous transfer can coexist, and FIG. 16 shows a state of a temporal transition of a transfer state on the bus at that time.

Here, the isochronous transfer is executed prior to the asynchronous transfer. The reason is CSP
After that, the isochronous transfer can be started with a gap length (isochronous gap) shorter than the gap length (subaction gap) of the idle period required to start the asynchronous transfer. Therefore,
Isochronous transfer is executed with priority over asynchronous transfer.

In the general bus cycle shown in FIG. 16, CSP is transferred from the cycle master to each node at the start of cycle #m. By CSP,
The operation of each node is synchronized, and a node that attempts to perform isochronous transfer after waiting for a predetermined idle period (isochronous gap) participates in bus arbitration and starts packet transfer. In FIG. 16, the channel e, the channel s, and the channel k are sequentially subjected to isochronous transfer. After the operations from the bus arbitration to the packet transfer are repeatedly performed for the given channel, when all the isochronous transfers in the cycle #m are completed, the asynchronous transfer can be performed.

That is, when the idle time reaches the subaction gap in which asynchronous transfer is possible, a node wishing to perform asynchronous transfer participates in bus arbitration.

However, the asynchronous transfer can be performed only when the sub-action gap for starting the asynchronous transfer is obtained after the completion of the isochronous transfer and before the time (cycle synch) to transfer the next CSP. Limited to

In the cycle #m shown in FIG. 16, after isochronous transfer for three channels, two packets including ack (packet 1,
Packet 2) has been transferred. After the asynchronous packet 2, it is time to start cycle m + 1 (cycle synch), and the transfer in cycle #m ends therewith.

However, during asynchronous or synchronous transfer, the next CS
When the time to transmit P arrives (cycle synch), the transfer is not forcibly interrupted, and after the transfer is completed, the CSP of the next cycle is transmitted after an idle period. That is, 1
If one cycle lasts more than 125 μS, the next cycle is shortened by 125 μS as much as the extension. Thus, the isochronous cycle can be exceeded or shortened on the basis of 125 μS.

However, the isochronous transfer is executed every cycle if necessary in order to maintain the real-time transfer, and the asynchronous transfer may be postponed to the next and subsequent cycles due to the shortened cycle time. The cycle master also manages such delay information.

(First Embodiment)

FIG. 17 is a diagram in which the interface of the 1394 serial bus is compared with each layer of the OSI model often used in LAN. The physical layer 1 and the data link layer 2 of the OSI model correspond to a physical layer 811 and a link layer 812, which are lower layers 4 of the interface of the 1394 serial bus. 1394 existing on the lower layer 4
The transport protocol layer 5 and the presentation layer 6 in the serial bus interface are OSI
It corresponds to the upper layer 3 including the network layer, transport layer, session layer, and presentation layer of the model. The LOGIN protocol 7, which is a feature of the present invention, operates between the lower layer 4 of the 1394 serial bus interface and the transport protocol layer 5.

In Example 1 shown in FIG. 17, a device conforming to the serial bus protocol (SBP-2) 8 for peripheral devices such as a printer is provided with a LOGIN protocol 7 so that a device of a partner can be provided. The user can be notified that data is to be exchanged using a protocol conforming to SBP-2.
Further, in Example 2 shown in FIG.
By providing the LOGIN protocol 7 for the device protocol 9 specialized on the interface of the 94 serial bus, it is possible to determine whether the devices support each other's protocol.

FIG. 18 is a diagram showing a basic operation of the LOGIN protocol. When the printer device executes the print task 10 from the host device, first, the printer protocols A, B, and C prepared for the printer are prepared. Of which print data is exchanged
The print data is determined based on the communication based on the GIN protocol 7, and thereafter, print data is exchanged according to the determined printer protocol. That is, when connecting to a host device, a printer device that supports several printer protocols first determines the transport protocol 5 provided in the host device by the LOGIN protocol 7, and then determines the transport protocol of the host device. The print task 10 is processed by selecting a printer protocol that matches the port protocol 5 and exchanging print data and commands in accordance with the selected printer protocol.

FIG. 19 is a diagram showing a connection form in the 1394 serial bus. Devices in which the LOGIN protocol 7 is mounted on the printer 11 corresponding to a plurality of printer protocols (PC 12, scanner 13, VCR 14).
) Indicates a connected state. The printer 11
By switching the printer protocol according to the transport protocol 5 of the partner device requesting the connection, determined by the LOGIN protocol 7, the printing task from each device can be processed without any problem.

FIG. 20 is a diagram showing a flow of the login operation. In the first step: the host device locks the target device (in this case a multi-protocol printer). The target device checks the capabilities (including the transport protocol and the like) of the host device, and the capabilities are stored in a register 503 described later. -The target device sets the capabilities (including the transport protocol etc.) of the host device. In the second step:-The print data is communicated using the protocol determined in the first step. In the third step, the host device disconnects the connection with the target device.

FIG. 21 shows the CSR of the 1394 serial bus provided in the printer which is the target device for the LOGIN protocol, and shows a lock register 501, a protocol register 502, and a capability register 503.

The capability register 503 of FIG. 21 stores information indicating a protocol that can be supported by each device, and each bit indicates a data transport protocol that can be independently supported. In the protocol register 502, a protocol actually used for communication is written.

These registers are arranged at predetermined addresses in the initial unit space in the address space of the 1394 serial bus. That is, as shown in FIG. 3, 0xFFFFF in the first 20 bits of the 48 bits of the address width given to the device is called a register space, and the first 512 bytes of the register (which is the core of the CSR architecture) CSR core).

In the register space, information common to the devices connected to the bus is stored. Also, 0 to 0xFFFF
D is called the memory space, and 0xFFFFE is called the private space. The private space is an address that can be used freely in the device, and is used for communication between the devices.

The lock register 501 indicates the locked state (exclusive state) of the resource. A value “0” indicates a state in which a login is possible, and a value other than “0” indicates that the user has already logged in the locked state. The capability register 503 has a plurality of bits, and independently indicates a data transport protocol that can be set for each bit. That is, a value “1” indicates that a protocol corresponding to a bit can be set, and a protocol corresponding to “0” cannot be set. The protocol register 502 indicates the currently set protocol, and the value of a bit corresponding to the bit of the capability register 503 corresponding to the set protocol becomes “1”.

FIG. 22 is a flowchart showing a login process in the host device.

In order to start login, first, the target device to be logged in, for example, the lock register 501 and the protocol register 50 of the printer
2 and the data of the capability register 503 are confirmed by a read transaction, that is, by specifying and reading the address space defined by the serial bus. Here, it is confirmed from the data of each bit of the capability register 503 whether the target device supports the protocol that the host device intends to use for communication (step S601). If the protocol of the host device is not supported by the target device, the login is stopped in the next step S602. That is, in the present embodiment, the host device can easily determine a plurality of protocols supporting the printer simultaneously by checking a plurality of bits of the capability register of the printer. Therefore, the protocol can be determined at high speed. Specifically, the host device can easily and quickly recognize a protocol that can be supported, as compared with a method of sequentially inquiring for a protocol that can be supported by the printer.

If the data in the lock register 501 is other than "0", it is assumed that another device is logging in and the login is stopped. Login register 501
If the data is "0", it is determined that the current login is possible (step S602). The contents of the lock register 501 can be confirmed by reading the contents by a read or lock transaction, as described above.

If the login is possible, the process proceeds to the resource lock process, where "1" is written into the lock register 501 of the printer using a lock transaction, and login is set (step S603). In this state, the target device is locked, control from other devices is impossible, and register change is also impossible.

As described above, with the resources of the target device locked, protocol setting is performed next. Therefore, as described above, each of the plurality of data transports has been confirmed. Since the printer according to the present embodiment, which is a target device, supports a plurality of printer protocols, it is necessary to know a protocol that can be used by the host device before receiving print data. In the present embodiment,
By setting the corresponding bit of the protocol register 502 of the printer by the write transaction of the host device, the protocol to be used is notified to the printer (step S604).

At this point, the protocol used by the host device for communication is notified to the target device, and the target device is in the locked state.
In this case, the print data is transmitted (step S
605).

When the data transmission is completed, the host device logs out of the printer by clearing the lock register 501 and the capability register 503 of the target device (step S60).
6).

FIG. 23 is a diagram showing a login process of a printer as a target device.

The printer normally waits for the host device to log in. The print request from the host device is transmitted to the printer lock register 50.
1, since it is started by reading the protocol register 502 and the capability register 503, it is necessary to keep the register readable from other devices at all times. It is assumed that the printer is locked by the host device that is to execute printout (step S701).

The printer waits for the next notification of the used protocol from the host device (step S70).
2). The reason for waiting for the notification of the used protocol after the printer is locked is to prevent the protocol register 502 from being rewritten by a request from another device during login.

When the printer is notified of the used protocol (step S703), the printer switches its own protocol to the notified used protocol (step S70).
4, S706, S708), communication is performed according to the protocol of the host device (steps S705, S70)
7, S709).

When the communication is completed, the printer confirms that the lock register 501 and the capability register 503 have been cleared (step S710), and returns to a state of waiting for login (step S701).

(Second Embodiment)

FIG. 24 is a diagram showing an operation in the second embodiment. Compared with the first embodiment shown in FIG. 18, the second embodiment has a protocol D in which the LOGIN protocol 7 is not mounted. The feature is that it also supports devices. That is, LOGIN protocol 7
In order to guarantee the printing operation not only for the device having the “A” but also for the device corresponding only to the existing protocol D (for example, the AV / C protocol), the printer is required to have the LO.
A printer protocol corresponding to a device not having the GIN protocol 7 is added.

To explain this operation, if the printer recognizes that the host device does not support the LOGIN protocol 7 by a print request made at the beginning of the connection, the printer communicates with the host device using the protocol D. If the communication is established, the print task 10 is executed according to the protocol D.

FIG. 25 is a diagram in which the second embodiment is compared with the OSI model. In Example 3, the third embodiment conforms to the current AV / C protocol in which the LOGIN protocol 7 is not implemented. The AV device 15 is a model. In Example 4, a model is a scanner 16 in which a non-standard protocol for a scanner without the LOGIN protocol 7 is installed. That is, even for a device having a protocol that does not implement the LOGIN protocol 7, if the printer can support the protocol of the device, the types of devices that can use the printer can be expanded.

In each of the above embodiments, I
Although the network is configured using the EEE1934 serial bus, the present invention is not limited to this. For example, the network is configured using an arbitrary serial interface such as a serial interface called Universal Serial Bus (USB). It can also be applied to networks that

The host device in each of the above-mentioned embodiments is, for example, a computer, a digital camera, a scanner, a DVD, a Set-top-Bo.
x, a digital television, a conference camera, a digital video, and a multifunction peripheral including them. On the other hand, target devices include monitors,
Computer, external storage device, Set-top-Bo
x, a printer, a multifunction peripheral including these, and the like can be used.

The present invention may be applied to a system composed of a plurality of devices as shown in FIG. 19, or to a data processing method in a device composed of one device.

An object of the present invention is to supply a storage medium storing program codes of software for realizing the functions of the host and terminal of each of the above-described embodiments to a system or an apparatus, and to provide a computer for the system or the apparatus. Needless to say, this can also be achieved by a program (or CPU or MPU) reading and executing a program code stored in a storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R,
A magnetic tape, a nonvolatile memory card, a ROM, or the like can be used. The functions of the above-described embodiments are realized by executing the program codes read by the computer, and the operating system running on the computer based on the instructions of the program codes.
It goes without saying that the present invention includes a case where the functions of the embodiments are implemented by performing part or all of the actual processing. Further, after the program code read from the storage medium is written to a memory provided in an extension function board inserted into the computer or a function extension unit connected to the computer, the function extension is performed based on the instruction of the program code. It goes without saying that a CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0176]

As described above, according to the present invention, a highly scalable data communication in which a communication protocol when performing data communication between a host device and a target device is not limited by the target device. Apparatus and systems can be provided. Particularly, since it is possible to support protocols of a plurality of types of devices (such as printers), the scalability is extremely high. In addition, IEEE 139
Such effects can be obtained in a data communication device or system using a serial interface such as the four standards. Further, data (image data and the like) can be directly transferred from the host device to the target device without going through the host computer.

Further, according to the present invention, a plurality of data transport protocols that can be supported on the device side are checked in advance, and thereafter, which data transport is used is determined. Protocol can be determined.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a network system configured using an IEEE 1394 serial interface.

FIG. 2 is a diagram illustrating a configuration of an IEEE 1394 serial interface.

FIG. 3 is a diagram for explaining an address space in the IEEE 1394 serial interface.

FIG. 4 is a diagram illustrating a cross section of a cable for an IEEE 1394 serial interface.

FIG. 5 is a diagram for explaining a DS-Link system.

FIG. 6 is a flowchart for explaining a network construction procedure in the IEEE 1394 serial interface.

FIG. 7 is a flowchart for explaining a route determination method.

FIG. 8 is a flowchart illustrating a procedure from determination of a parent-child relationship to setting of all node IDs.

FIG. 9 is a diagram illustrating an example of a network.

FIG. 10 is a diagram for explaining bus arbitration.

FIG. 11 is a flowchart illustrating a procedure of arbitration.

FIG. 12 is a diagram for explaining a temporal transition state in asynchronous transfer.

FIG. 13 is a diagram illustrating a packet format for asynchronous transfer.

FIG. 14 is a diagram for describing a temporal transition state in isochronous transfer.

FIG. 15 is a diagram for explaining a packet format for isochronous transfer.

FIG. 16 is a diagram for explaining a state of a temporal transition of a transfer state on a bus when asynchronous transfer and isochronous transfer are mixed.

FIG. 17 is a diagram illustrating a comparison between an IEEE 1394 serial interface and an OSI model.

FIG. 18 is a diagram for explaining a basic operation of the LOGIN protocol.

FIG. 19 is a diagram illustrating an IEEE 139 according to the first embodiment.
FIG. 4 is a diagram for explaining a connection form in a 4-serial interface.

FIG. 20 is a diagram illustrating a flow of a login operation.

FIG. 21 is a diagram for explaining a CSR provided in the printer for the LOGIN protocol.

FIG. 22 is a flowchart illustrating a LOGIN process in the host device.

FIG. 23 is a flowchart illustrating a LOGIN process in the target device.

FIG. 24 is a diagram for explaining an operation in the second embodiment.

FIG. 25 is a diagram for explaining a comparison with an OSI model.

[Explanation of symbols]

 1 Physical layer of OSI model 2 Data link layer 3 Upper layer 4 Upper layer 5 Transport protocol layer 6 Presentation layer 7 LOGIN protocol 8 Serial bus protocol (SBP-2) 9 Device protocol

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Atsushi Nakamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Naohisa Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (43)

[Claims] 1. A data communication method for performing data communication using a serial bus, comprising: an information acquisition step of acquiring capability information of a target device by communication using an initial protocol; and a capability information acquired in the information acquisition step. On the basis of,
Setting a communication protocol that can be used for data communication to the target device; anda communication step of performing data communication with the target device based on the communication protocol set in the setting step. Characteristic data communication method. 2. The data communication method according to claim 1, wherein the target device is capable of supporting a plurality of communication protocols, and the capability information includes information indicating the plurality of communication protocols. . 3. The data communication method according to claim 1, wherein the target device includes a printer, and the data communicated by the communication protocol includes image data. 4. The apparatus according to claim 1, wherein the target device includes an inkjet printer, and the plurality of communication protocols supported by the target device include those adapted for image formation by the inkjet printer. Data communication method. 5. A data communication method for performing data communication using a serial bus, comprising: an information returning step of returning capability information in response to a request from a host device using an initial protocol; A setting step of setting a communication protocol used for data communication according to an instruction from the host device based on the capability information; and performing data communication with the host device based on the communication protocol set in the setting step. And a communication step. 6. The data communication method according to claim 5, wherein said capability information is compatible with a plurality of said communication protocols, and said capability information includes information indicating said plurality of communication protocols. 7. The data communication method according to claim 5, wherein the data communicated by the communication protocol includes image data. 8. The data communication method according to claim 6, wherein said plurality of communication protocols include ones adapted for image formation by an ink jet printer. 9. The data communication method according to claim 1, wherein the data communicated by the communication protocol includes image data obtained by imaging. 10. The serial bus is an IEEE 139
6. A data communication method according to claim 1, further comprising a bus conforming to or conforming to four standards. 11. The serial bus is an IEEE 139
4 includes a bus conforming to or conforming to the 4 standards, the capability information includes information stored in a CSR register of an address space in the IEEE 1394 standard, and the setting step includes a step of setting the communication protocol by the CSR register. 6. The data communication method according to claim 1, further comprising: 12. The system according to claim 12, wherein the serial bus is a Universals.
The data communication method according to claim 1, further comprising a bus conforming to or conforming to an al SerialBus standard. 13. The data communication method according to claim 1, wherein said initial protocol includes a protocol executed in a layer higher than a data link layer of an OSI model. 14. A data communication method for performing data communication using a serial bus, comprising: a receiving step of receiving a connection request from a host device; and recognizing that the host device does not support a predetermined protocol. In the case, a setting step of setting a communication protocol used for data communication, a trial step of trying to communicate with the host device using the communication protocol set in the setting step, and a communication with the host device by the trial step A communication step of performing data communication with the host device using the communication protocol set in the setting step when the condition is satisfied. 15. A data communication device for performing data communication using a serial bus, comprising: communication means capable of supporting an initial protocol and a plurality of communication protocols for data communication; and information indicating the plurality of communication protocols. Storage means for storing capability information; and setting means for setting a communication protocol of the communication means. The communication means stores the communication information in the storage means based on a request from a host device using the initial protocol. The data communication apparatus according to claim 1, wherein the setting information is transmitted to the host device, and the setting means sets a communication protocol of the communication means in accordance with an instruction of the host device using the initial protocol. 16. A data communication device for performing data communication using a serial bus, comprising: communication means capable of supporting an initial protocol and a plurality of communication protocols for data communication; and controlling data communication between the host device and the communication means. Control means for recognizing that the communication means recognizes that the host device does not support the initial protocol by the connection request received from the host device, Is set, and communication with the host device is attempted using the communication protocol. When communication with the host device is established, control is performed to perform data communication with the host device using the set communication protocol. A data communication device, characterized in that: 17. A data communication system for performing data communication using a serial bus, wherein at least one host device and at least one target device according to the data communication method according to claim 1. A data communication system comprising: performing data communication between the at least one host device and the at least one target device based on a set communication protocol. 18. A data communication system including first and second devices and a serial bus defining a predetermined address space for each device, wherein the first device is defined by the serial bus. A first protocol capability storage unit that stores information independently presenting a plurality of data transport protocols that can be supported and that are present on the same address space, and wherein the second device has the first protocol Second confirmation means for confirming the contents of the capability storage means by designating and reading the address space defined by the serial bus; and a data transport protocol based on the contents of the first protocol capability storage means. And second determination means for determining the second determination means. A data communication system characterized by confirming a plurality of available data transport protocols prior to a decision at a stage. 19. The device according to claim 18, wherein the first device further includes a lock storage unit that exists in an address space defined by the serial bus and stores information indicating a resource occupation state. A data communication system as described. 20. The first device, further comprising: a lock storage unit that exists in an address space defined by the serial bus and stores information indicating a resource occupation state. The first device is occupied exclusively by the lock content confirmation means for confirming the contents of the lock storage means by a read or lock transaction designating an address space defined by the serial bus, and the confirmation result of the lock content confirmation means. 19. The data communication system according to claim 18, further comprising: a determination unit configured to determine whether the data communication is performed. 21. The data communication system according to claim 18, wherein said data transport protocol includes a printer protocol. 22. The data communication system according to claim 21, wherein said printer protocol includes a protocol for transferring data to be printed. 23. The data communication system according to claim 18, wherein said second device includes a device that outputs image data. 24. The second device, a computer, a digital camera, a scanner, a DVD, a Set-t
24. The data communication system according to claim 23, wherein the data communication system is a device including at least one of an op-box, a digital television, a conference camera, a digital video, and a multifunction peripheral including the same. 25. The data communication system according to claim 18, wherein said first device further includes protocol storage means for storing a data transport protocol determined by said second determination means. 26. The serial bus is an IEEE 139
19. The data communication system according to claim 18, including a bus conforming to or conforming to four standards. 27. The serial bus includes a DS-link.
The data communication system according to claim 18, further comprising a bus that modulates and transfers data according to a scheme. 28. The apparatus according to claim 28, wherein said second confirmation means confirms the contents of said first protocol capability storage means by a read transaction specifying an address space defined by said serial bus. 19. The data communication system according to 18. 29. The data communication system according to claim 28, wherein said read transaction is executed in a layer lower than a transport protocol layer of said serial bus. 30. The device according to claim 18, wherein the first device includes a device to which image data is input.
A data communication system as described. 31. The device according to claim 30, wherein the first device is a device including at least one of a monitor, a computer, an external storage device, a set-top-box, a printer, and a multifunction peripheral including these devices. A data communication system as described. 32. A second protocol capacitor which is present in an address space defined by the serial bus and stores information independently indicating a plurality of data transport protocols which can be supported. 19. The data communication system according to claim 18, further comprising an ability storage unit. 33. The first device, wherein the first device confirms the contents of the protocol capability storage by designating an address space defined by the serial bus, and the protocol capability. First determining means for determining a data transport protocol based on the contents of the storage means, wherein the first confirming means determines a plurality of compatible data prior to the determination by the first determining means. 19. The data communication system according to claim 18, wherein a transport protocol is confirmed. 34. A data communication apparatus which is at least one of the plurality of devices for configuring a data communication system including a plurality of devices and a serial bus defining a predetermined address space for each device. Reading information independently indicating a plurality of compatible data transport protocols stored in the address space defined by the serial bus, by designating the address space defined by the serial bus; And a determining means for determining a data transport protocol based on the result of the confirmation by the confirming means. The confirming means comprises a plurality of compatible data prior to the decision by the deciding means. A data communication system characterized by confirming a transport protocol. 35. A data communication device, which is a first device for configuring the data communication system according to claim 18. 36. A data communication device, which is a second device for configuring the data communication system according to claim 18. 37. A data communication method for performing data communication between a first device and a second device via a serial bus defining a predetermined address space for each device, comprising: Confirmation that the information indicating the protocol is stored in the protocol capability register existing on the address space defined by the serial bus by confirming by reading by specifying the address space defined by the serial bus. And a determining step of determining a data transport protocol based on a result of the confirmation in the confirming step. The confirming step includes, prior to the determination by the determining step, a plurality of available data transport protocols. Confirming the data. Data communication method. 38. A data communication method for a device connected to a serial bus that defines a predetermined address space for each device, wherein information indicating an applicable data transport protocol is defined by the serial bus. A data communication method comprising a step of reading from a protocol capability register existing in an address space. 39. A data communication method for a device connected to a serial bus that defines a predetermined address space for each device, wherein the data communication method is stored in a protocol capability register of another device connected to the serial bus. A confirmation step of confirming contents by designating and reading an address space defined by the serial bus; and a determination step of determining a data transport protocol based on a confirmation result in the confirmation step, wherein the confirmation The data communication method characterized in that the step includes a step of confirming a plurality of applicable data transport protocols prior to the determination by the determining step. 40. A computer reads out processing steps for performing data communication in a system including a first device, a second device, and a serial bus defining a predetermined address space for each device. A storage medium capable of storing the information indicating a data transport protocol which can be supported, wherein the content of the protocol capability register existing in an address space defined by the serial bus is stored. And a determination step of determining a data transport protocol based on a result of the confirmation in the confirmation step. Prior to the decision in the decision step above, Confirming an available data transport protocol. 41. A computer-readable storage medium storing, in a computer-readable manner, processing steps for performing data communication of a device connected to a serial bus that defines a predetermined address space for each device. A storage medium characterized by including a step of reading information indicating a compatible data transport protocol from a protocol capability register existing in an address space defined by the serial bus. 42. A computer-readable storage medium storing processing steps for performing data communication of a device connected to a serial bus that defines a predetermined address space for each device, wherein the computer-readable storage medium stores the processing steps. A step of confirming contents stored in a protocol capability register of another device connected to the serial bus by designating and reading an address space defined by the serial bus; Determining a data transport protocol based on the result of the check in the step, wherein the checking step includes a step of checking a plurality of available data transport protocols prior to the determination by the determining step. A storage medium characterized by the following. 43. A storage medium in which processing steps for performing data communication using a serial bus are stored in a computer readable manner, wherein the processing steps are performed in accordance with claim 1 to claim 14, and claim 37 to claim 3.
9. A storage medium, comprising a processing step of the data communication method according to any one of 9.