JPH10229538A - Data communication system, print system and data communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a collision of instructions by an operation part between nodes connected by a network e.g. between a video equipment and a printer. SOLUTION: This system is provided with a 1st node (VTR2) having an image display monitor and an operation part and a 2nd node (printer 1) having an operation part without an image display monitor. In this case, the 1st node and the 2nd node are connected by a Ds-Link method and have a mediation means that mediates instruction from the operation part of the 1st node and instruction from the operation part of the 2nd node.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication system and a print system data communication device, and more particularly to a system for performing data communication between devices.

[0002]

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

A digital camera or a digital video camera is also one of the peripheral devices as an input means to a personal computer (hereinafter, referred to as a PC). In recent years, images such as still images and moving images taken by a digital camera or a video camera have been transmitted to a PC. The technology in the field of importing data to a hard disk, storing the data on a hard disk, or editing the data on a PC, and then performing color printing with a printer is advanced, and the number of users is increasing.

[0004] When outputting the captured image data from a PC to a printer or a hard disk, the above-mentioned SCSI is used.
In such a case, in order to send information having a large data amount such as image data, such a digital I / F has a high transfer data rate and a high data transfer rate. Versatile things are needed.

[0005] As described above, conventionally, each device is connected to a PC serving as a host, and image data captured by a camera is printed via the PC.

However, the SCS described in the above conventional example is
I has a low transfer data rate, a thick cable for parallel communication, the types and number of connected peripheral devices, and the connection method are limited, and many inconveniences are pointed out. ing.

[0007] Also, many of the general home PCs are PCs.
In many cases, a connector for connecting SCSI or other cables is provided on the back of the device, and the shape of the connector is large. Even when connecting a portable or portable device such as a digital camera or a video camera which is not usually fixed, the device must be connected to the rear connector of the PC, which is very troublesome.

In addition, many peripheral devices are usually connected to a personal computer. In the future, the types of peripheral devices will further increase, and further improvements in I / F will not only limit the number of peripheral devices but also many digital devices. When network-based communication becomes possible, it becomes very convenient.On the other hand, communication with a very large amount of data is frequently performed depending on the devices. It may also affect communication between devices. For example, when the user wants to print an image continuously or quickly, communication between devices that are not aware of the user affects data communication between the PC and the printer, affecting the entire network or the PC acting as a host. And printing of the image may not be performed normally or may be delayed. As described above, there are also problems such as a load on the PC due to network congestion and print data communication depending on the operation state of the PC.

In order to solve the conventional problems, the present invention solves the problems of the conventional digital I / F as much as possible, and provides a general-purpose digital I / F that is unifiedly mounted on each digital device. (For example, IEEE1394-1995 high-performance serial bus) using a PC, printer,
In addition, realize data communication between devices when a peripheral device, a digital camera, a camera-integrated digital VTR, etc. are connected in a network configuration, and directly transfer image data from a digital camera or a camera-integrated digital VTR to a printer for printing. , So-called direct printing is realized.

However, in such a case, the operation of the printer and the operation unit of the camera cannot be arbitrated.

[0011]

A system having a first node having an image display monitor and an operation unit, and a second node having an operation unit without having an image display monitor. The first node and the second node are connected by a DS-Link system, and arbitration means for arbitrating an instruction from the operation unit of the first node and an instruction from the operation unit of the second node is provided. It is characterized by having.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 Hereinafter, Embodiment 1 will be described with reference to the drawings.

FIG. 2 shows an example of a network configuration according to an embodiment of the present invention.

In this embodiment, since a digital I / F for connecting each device uses an IEEE1394 serial bus,
The IEEE1394 serial bus will be described in advance.

<< Summary of IEEE 1394 Technology >> With the advent of home digital VTRs and DVDs, it is necessary to support real-time and high information amount data transfer of video data and audio data. In order to transfer such video and audio data in real time, and to transfer it to a personal computer (PC) or other digital devices, an interface capable of high-speed data transfer with the necessary transfer functions is required. The interface developed from such a point of view is IEEE1394-1995 (High Performance Serial
l Bus) (hereinafter 1394 serial bus).

FIG. 7 shows an example of a network system configured using a 1394 serial bus. This system is equipped with devices A, B, C, D, E, F, G, H, between AB, between AC,
, DE, CF, CG, and CH are connected by a twisted pair cable of a 1394 serial bus. The devices A to H are, for example, PCs, digital VTRs, DVDs, digital cameras, hard disks, monitors, and the like.

The connection method between the devices is such that the daisy chain method and the node branch method can be mixed.
A highly flexible connection is possible.

Each device has a unique ID, and recognizes each other to form a single network in a range connected by a 1394 serial bus. By simply connecting each digital device sequentially with a single 1394 serial bus cable, each device plays a role of relay and constitutes one network as a whole. It also has a function of automatically recognizing the device and the connection status when a cable is connected to the device by the Plug & Play function, which is a feature of the 1394 serial bus.

In the system shown in FIG. 7, when a device is deleted from the network or newly added, the bus is automatically reset, and the network configuration up to that point is reset. From
Rebuild a new network. With this function, the configuration of the network at that time can be constantly set and recognized.

The data transfer rate is 100/200/400 Mb
It has ps, and devices with higher transfer speeds support lower transfer speeds and are compatible.

The data transfer mode includes asynchronous data such as control signals (Asynchronous data: hereinafter referred to as As).
Asynchronous transfer mode for transferring synchronous data (Inc data), transferring synchronous data (Isochronous data: hereinafter Iso data) such as real-time video data and audio data
There is an Isochronous transfer mode. This Async data and Iso
In each cycle (usually one cycle of 125 μS), data is transferred together with a cycle start packet (CSP) indicating the start of a cycle, followed by transfer of iso data in a cycle with priority given to transfer of iso data.

Next, FIG. 8 shows the components of the 1394 serial bus.

The 1394 serial bus has a layer (hierarchical) structure as a whole. As shown in FIG. 8, the most hardware is a 1394 serial bus cable, which has a connector port to which a connector of the cable is connected, and a physical layer and a link layer as hardware on the connector port.

The hardware part is a substantial part of an interface chip. The physical layer performs coding and control related to connectors, and the link layer performs packet transfer and cycle time control.

The transaction layer of the firmware section manages data to be transferred (transacted) and issues commands such as Read and Write. The serial bus management is a part that manages the connection status and ID of each connected device and manages the configuration of the network.

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

The software application
The layer differs depending on the software used, and is a part that defines how data is placed on the interface.
It is specified by a protocol such as a protocol.

The above is the configuration of the 1394 serial bus.

Next, FIG. 9 shows a diagram of the address space in the 1394 serial bus.

Each device (node) connected to the 1394 serial bus must have a 64-bit address unique to each node. And by storing this address in ROM, you can always recognize yourself and the other party's node address,
You can also communicate with the other party.

The addressing of the 1394 serial bus is based on the IE
The address is set according to the EE1212 standard. The first 10 bits are used for specifying the bus number, and the next 6 bits are used for the node ID.
Used to specify a number. The remaining 48 bits become the address width given to the device, and can be used as a unique address space. The last 28 bits store information such as identification of each device and designation of use conditions as an area of unique data.

The above is the outline of the technology of the 1394 serial bus.

Next, the technology that can be said to be a feature of the 1394 serial bus will be described in more detail.

<< Electrical Specifications of 1394 Serial Bus >>
1 shows a sectional view of a 1394 serial bus cable.

In the 1394 serial bus, the connection cable
A power supply line is provided 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 dropped due to a failure, and the like.

The voltage of the power supply flowing in the power supply line is 8 to 40 V,
The current is specified as a maximum current of DC 1.5A.

<< DS-Link Encoding >> FIG. 11 is a diagram for explaining the DS-Link encoding method of the data transfer format employed in the 1394 serial bus.

In the 1394 serial bus, DS-Link (Data /
Strobe Link) coding method is adopted. This DS-L
The ink coding scheme is suitable for high-speed serial data communication, and its configuration requires two signal lines. The main data is sent to one of the twisted pairs, and the strobe signal is sent to the other twisted pair.

On the receiving side, the clock can be reproduced by taking the exclusive OR of this communicated data and the strobe.

Advantages of using the DS-Link encoding method include higher transfer efficiency compared to other serial data transfer methods, and the elimination of a PLL circuit, thereby reducing the cost of the controller LSI.
Power consumption because the transceiver circuit of each device can be put into a sleep state because there is no need to send information indicating that the device is in an idle state when there is no data to be transferred. Can be reduced.

<< Bus Reset Sequence >> In the 1394 serial bus, each connected device (node) is given a node ID, and is recognized as a network configuration.

When there is a change in the network configuration, for example, a change occurs due to an increase or decrease in the number of nodes due to insertion / removal of a node or power ON / OFF, etc., and it is necessary to recognize a new network configuration. Each of the detected nodes transmits a bus reset signal on the bus to enter a mode for recognizing a new network configuration. The method of detecting the change at this time is performed by detecting a change in the bias voltage on the 1394 port board.

When a bus reset signal is transmitted from a certain node, the physical layer of each node transmits the bus reset signal to the link layer at the same time as receiving the bus reset signal, and transmits the bus reset signal to another node. . After all the nodes finally detect the bus reset signal, the bus reset is activated.

The bus reset is also activated by the above-mentioned activation by hardware insertion / removal due to a cable disconnection or network abnormality or the like, and also by directly issuing an instruction to the physical layer by host control from a protocol.

Further, when the bus reset is activated, the data transfer is suspended, the data transfer during this period is waited, and after the end, the data transfer is resumed under a new network configuration.

The bus reset sequence has been described above.

<< 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. The general sequence from the bus reset to the determination of the node ID at this time will be described with reference to the flowcharts of FIGS.

The flowchart of FIG. 19 shows a series of bus operations from the occurrence of a bus reset until the node ID is determined and data transfer becomes possible.

First, as step S101, the occurrence of a bus reset in the network is constantly monitored, and if a bus reset occurs due to power ON / OFF of a node, the process proceeds to step S102.

In step S102, from the reset state of the network, a parent-child relationship is declared between the directly connected nodes in order to know the connection status of the new network. When the parent-child relationship is determined between all the nodes as step S103, step S104
One route is decided as. Until the parent-child relationship is determined between all nodes, the parent-child relationship is declared in step S102, and the route is not determined.

When the route is determined in step S104,
Next, in step S105, a node ID setting operation for giving an ID to each node is performed. In a given node order,
The node ID is set, and the setting operation is repeatedly performed until the IDs are given to all the nodes. When the IDs are finally set to all the nodes in step S106, the new network configuration is recognized by all the nodes. Thus, as a step S107, data transfer between nodes can be performed, and data transfer is started.

When the state of step S107 is reached, a mode for monitoring the occurrence of a bus reset is entered again. If a bus reset occurs, steps S101 to S1 are performed.
The setting work up to 06 is repeated.

The above is a description of the flowchart of FIG. 19. The flowchart from FIG. 19 shows the part from the bus reset to the route determination and the procedure from the route determination to the end of the ID setting in a more detailed flowchart. Are shown in FIGS. 20 and 21, respectively.

First, the flowchart of FIG. 20 will be described.

When a bus reset occurs in step S201, the network configuration is reset once. The occurrence of a bus reset is constantly monitored in step S201.

Next, in step S202, as a first step of re-recognizing the reset network connection status, a flag indicating a leaf (node) is set for each device. Further, in step S203, each device checks how many ports of its own are connected to other nodes.

In accordance with the result of the number of ports in step S204, the number of undefined (parent-child relationship is not determined) ports is examined in order to start the declaration of the parent-child relationship.
Immediately after the bus reset, the number of ports is equal to the number of undefined ports. However, as the parent-child relationship is determined, the number of undefined ports detected in step S204 changes.

First, immediately after the bus reset, only the leaves can declare the parent-child relationship first. The fact that the port is a leaf can be known by checking the number of ports in step S203. At step S205, the leaf declares "I am a child and the other is a parent" to the node connected thereto, and ends the operation.

The node which has a plurality of ports in step S203 and is recognized as a branch immediately after the bus reset has the number of undefined ports> 1 in step S204, so the process proceeds to step S206, where a flag of branch is first set. In step S207, the process waits for reception of “parent” in the parent-child relationship declaration from the leaf.

The leaf declares a parent-child relationship, and the branch that has received the declaration in step S207 appropriately checks the number of undefined ports in step S204. It becomes possible to declare "I am a child" in step S205 to the connected node. After the second time, even if the number of undefined ports is confirmed in step S204, for a branch having two or more ports, the process waits again in step S207 to accept a "parent" from a leaf or another branch.

Finally, if any one branch or exceptional leaf (because it did not operate quickly enough to make a child declaration) becomes zero as a result of the number of undefined ports in step S204, The only node for which the declaration of the parent-child relationship of the entire network has been completed and the number of undefined ports has become zero (all are determined as parent ports) is flagged as a root as step S208,
In step S209, the route is recognized.

In this manner, the steps from the bus reset shown in FIG. 20 to the declaration of the parent-child relationship between all the nodes in the network are completed.

Next, the flowchart of FIG. 21 will be described.

First, in the sequence up to FIG. 20, flag information of each node such as leaf, branch, and root is set, and based on this, classification is performed in step S301.

As a task of assigning an ID to each node, an ID can be first set from the leaf. The IDs are set in ascending order of leaf → branch → route (node number = 0).

At step S302, the number N (N is a natural number) of leaves existing in the network is set. Thereafter, in step S303, each leaf requests the root to give an ID. If there are a plurality of such requests, the route performs arbitration (operation of arbitrating one) in step S304, and step S305.
The ID number is given to one of the winning nodes, and a failure result is notified to the losing node. I as step S306
The leaf for which acquisition of D has failed fails issues an ID request again, and repeats the same operation. At step S307, the ID information of the node is broadcast and transferred to all nodes from the leaf whose ID has been acquired. When the broadcast of the one node ID information ends, the number of remaining leaves is reduced by one in step S308. Here, as step S309, when the number of remaining leaves is one or more, the operation from the ID request of step S303 is repeatedly performed.
Eventually, when all the leaves broadcast the ID information, step S309 becomes N = 0, and the process proceeds to the branch ID setting.

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

First, as step S310, the number M (M is a natural number) of branches existing in the network is set. Thereafter, in step S311, each branch requests the root to give an ID. On the other hand, the root performs arbitration in step S312, and gives the branch in order from the winning branch to the next youngest number given to the leaf. In step S313, the root notifies the branch that issued the request of ID information or a failure result. In step S314, the branch whose ID acquisition has failed fails issues an ID request again, and repeats the same operation. In step S315, the ID information of the node is transferred to all nodes by broadcasting from the branch from which the ID has been obtained. When the broadcasting of the one node ID information ends, the number of remaining branches is reduced by one in step S316. Here, as step S317, when the number of the remaining branches is one or more, the operation from the ID request in step S311 is repeated, and the operation is repeated until all the branches finally broadcast the ID information.
When all the branches have acquired the node ID, M = 0 in step S317, and the branch ID acquisition mode ends.

At this point, since only the root node has not acquired the ID information at the end, step S
The lowest number not given as 318
A D number is set, and the route ID information is broadcast in step S319.

Thus, as shown in FIG. 21, the procedure from the determination of the parent-child relationship to the setting of the IDs of all the nodes is completed.

Next, the operation in the actual network shown in FIG. 12 as an example will be described with reference to FIG.

As shown in FIG. 12, a node A and a node C are directly connected below the (root) node B, and a node D is directly connected below the node C.
Further, below the node D, there is a hierarchical structure in which the nodes E and F are directly connected. The procedure for determining the hierarchical structure, the root node, and the node ID will be described below.

After 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. The parent and child can be said to be such that the parent is higher in the hierarchical structure and the child is lower.

In FIG. 12, it is the node A that first declared the parent-child relationship after the bus reset. Basically, a node that has a connection to only one port of a node (called a leaf) can declare a parent-child relationship. This allows the user to first know that there is only one port connection, thereby recognizing that it is at the edge of the network and determining the parent-child relationship from the node that operates earlier in that. Thus, the port on the side that has declared the parent-child relationship (node A between AB) is set as a child, and the port on the other side (node B) is set as a parent.
Thus, a child-parent is determined between the nodes A and B, a child-parent is determined between the nodes ED, and a child-parent is determined between the nodes FD.

Further up in the hierarchy, among nodes having a plurality of connection ports (referred to as branches), the parent-child relationship is declared further higher in order from the node which received the declaration of the parent-child relationship from another node. To go. In FIG. 12, first, after the parent-child relationship between the node D and the node D-F is determined, a parent-child relationship is declared for the node C. As a result, the node D is determined as the child-parent between the nodes D and C. ing.

The node C that has received the declaration of the parent-child relationship from the node D has declared the parent-child relationship to the node B connected to another port. As a result, a child-parent is determined between the nodes C and B.

In this way, a hierarchical structure as shown in FIG. 12 is formed, and the node B which has become the parent in all finally connected ports is determined as the root node. There is only one route in one network configuration.

In FIG. 12, node B is determined to be the root node. This is because node B, which has received the parent-child relationship declaration from node A, makes a parent-child relationship declaration for other nodes at an early timing. If so, the root node may have moved to another node. That is, any node may become a root node depending on the transmission timing, and the root node is not always constant even in the same network configuration.

Once the root node has been determined,
Enter the ID determination mode. Here, all nodes notify their determined node IDs to all other nodes (broadcast function).

The self ID information includes its own node number, information on the connected position, the number of ports it has, the number of connected ports, information on the parent-child relationship of each port, and the like.

The procedure for assigning node ID numbers is as follows:
First, it can be started from a node (leaf) that has connection to only one port, and node number = 0,
1, 2, and so on.

The node that has obtained the node ID transmits information including the node number to each node by broadcast.
As a result, it is recognized that the ID number is “assigned”.

When all the leaves have obtained their own node IDs, the next step is to move to the branch and follow the leaf node ID
A number is assigned to each node. Like the leaf, the node IDs are sequentially assigned from the branch to which the node ID number is assigned.
Broadcast information, and finally the root node
Broadcast ID information. That is, the root always has the largest node ID number.

As described above, the nodes of the entire hierarchical structure
The ID assignment is completed, the network configuration is reconstructed, and the bus initialization is completed.

<< Arbitration >> In the 1394 serial bus, arbitration (arbitration) of the right to use the bus is always performed prior to data transfer. Since the 1394 serial bus is a logical bus-type network in which each device connected individually relays the transferred signal and transmits the same signal to all devices in the network, packet collision occurs. Arbitration is necessary to prevent This allows only one node to transfer at a given time.

As a diagram for explaining arbitration, FIG. 13A shows a bus use request diagram, and FIG. 13B shows a bus use permission diagram.

When arbitration starts, one or more nodes issue a bus use request to the parent node. Node C and node F in Fig. 13 (a)
Is the node issuing the request for the right to use the bus. The parent node (node A in FIG. 13) that has received this further issues (relays) a request for the right to use the bus toward the parent node.
This request is finally delivered to the arbitration route.

The root node that has received 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 has won the arbitration is given permission to use the bus. FIG.
In (b), use permission is given to the node C, and use of the node F is rejected. A DP (data prefix) packet is sent to the node that lost the arbitration,
Notify that they were rejected. The rejected node use request waits until the next arbitration.

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

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

In order for a node to be able to start data transfer,
The bus must be idle. In order to recognize that the data transfer that has been performed earlier is completed and that the bus is currently idle, a predetermined idle time gap length (eg, sub-action. Each node determines that its own transfer can be started by passing the gap.

At step S401, Async data, Iso
It is determined whether or not a predetermined gap length corresponding to data to be transferred, such as data, is obtained. Unless the predetermined gap length is obtained, the request for the right to use the bus required to start the transfer cannot be made, so the process waits until the predetermined gap length is obtained.

If a predetermined gap length is obtained in step S401, it is determined in step S402 whether there is data to be transferred. If so, a request for a bus use right is issued in step S403 to secure a bus for transfer. Emit to the route. At this time, the transmission of the signal indicating the request for the right to use the bus is finally delivered to the route while relaying each device in the network, as shown in FIG. If there is no data to be transferred in step S402, the process stands by.

Next, as step S404, step S4
When the route receives one or more bus use requests of 03, the route checks the number of nodes that have issued use requests in step S405. The selection value in step S405 is the number of nodes = 1
If (the node that has issued the use right request is one), the immediately subsequent bus use permission is given to that node. If the selection value in step S405 is the number of nodes> 1 (the number of nodes requesting use is plural), the route is set to step S406.
Arbitration work to determine one node to which use permission is given. This arbitration work is fair, and the same node does not always obtain permission each time, and the right is equally given.

In step S407, a selection is made to divide the route into one node whose route has been arbitrated and the use of which has been permitted, and another node that has lost the node among the plurality of nodes that have issued the use request in step S406. Here, for one node that has been arbitrated and has obtained use permission, or a node that has obtained use permission without arbitration based on the selection value of step S405 and the number of use request nodes = 1, the route is set to that node as step S408. A permission signal is sent to it. The node that has received the permission signal starts transferring data (packets) to be transferred immediately after receiving the permission signal. In addition, as a step S409, a node that has lost the arbitration in step S406 and is not permitted to use the bus receives a DP (data pre
fix) A packet is sent, and the node that has received the packet returns to step S401 to issue a bus use request to perform transfer again, and waits until a predetermined gap length is obtained.

The above is the description of the flowchart of FIG. 22 for explaining the flow of arbitration.

<< Asynchronous Transfer >> The asynchronous transfer is an asynchronous transfer. FIG. 14 shows a temporal transition state in the asynchronous transfer. The first sub-action gap in FIG. 14 indicates the idle state of the bus. When the idle time reaches a certain value, the node desiring transfer determines that the bus can be used and executes arbitration for acquiring the bus.

When the bus use permission is obtained by arbitration, data transfer is executed in the form of a packet.
After the data transfer, the receiving node acknowledges the ack (reception confirmation return code) of the reception result for the transferred data.
After a short gap of ap, the transfer is completed by returning and responding or sending a response packet. The ack is composed of 4 bits of information and 4 bits of a checksum, and includes information such as success, busy status, and pending status, and is immediately returned to the source node.

Next, FIG. 15 shows an example of the packet format of the asynchronous transfer. The packet has a header part in addition to the data part and the data CRC for error correction, and the header part has a destination node ID as shown in FIG.
The source node ID, transfer data length, various codes, etc. are written and the transfer is performed.

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 its own address is ignored, so that only one destination node reads the packet.

The above is the description of the asynchronous transfer.

<< Isochronous (Synchronous) Transfer >> Isochronous transfer is synchronous transfer. This isochronous transfer, which can be said to be the biggest feature of the 1394 serial bus, is especially
This transfer mode is suitable for transferring data that requires real-time transfer, such as multimedia data such as VIDEO video data and audio data.

Also, if the asynchronous transfer (asynchronous) is 1
In contrast to one-to-one transfer, this isochronous transfer is uniformly transferred from one transfer source node to all other nodes by the broadcast function.

FIG. 16 is a diagram showing a temporal transition state in the isochronous transfer.

The isochronous transfer is executed at fixed time intervals on the bus. This time interval is called an isochronous cycle. The isochronous cycle time is 125 μS. A cycle start packet indicates the start time of each cycle, and plays a role of adjusting the time of each node. The node that transmits the cycle start packet is a node called a cycle master. After a transfer in the previous cycle is completed, a predetermined idle period (subaction gap) is passed, and then the start of this cycle is announced. Send a cycle start packet. The time interval at which this cycle start packet is transmitted is 125 μS.

As shown in FIG. 16 as channel A, channel B and channel C, a plurality of types of packets can be distinguished and transferred by being given channel IDs in one cycle. This allows real-time transfer between a plurality of nodes at the same time, and the receiving node fetches only the data of the channel ID desired by itself. This channel ID does not represent the address of the transmission destination, but merely gives a logical number for the data. Therefore, the transmission of a certain packet is transmitted in a broadcast manner from one source node to all other nodes.

Prior to the packet transmission in the isochronous transfer, arbitration is performed as in the asynchronous transfer. However, since it is not one-to-one communication as in the asynchronous transfer, there is no ack (reception confirmation reply code) in the isochronous transfer.

The iso gap (isochronous gap) shown in FIG. 16 indicates an idle period necessary for recognizing that the bus is empty before performing the isochronous transfer. After the predetermined idle period has elapsed, a node that wishes to perform isochronous transfer determines that the bus is free, and can perform arbitration before transfer.

Next, an example of a packet format for isochronous transfer will be described with reference to FIG.

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 has a transfer data length and a channel length as shown in FIG. NO, other various codes, a header CRC for error correction, and the like are written and transferred.

The above is the description of the isochronous transfer.

<< Bus Cycle >> In actual transfer on the 1394 serial bus, isochronous transfer and asynchronous transfer can coexist. FIG. 18 shows a temporal transition of the transfer state on the bus in which the isochronous transfer and the asynchronous transfer are mixed at that time.

The isochronous transfer is executed prior to the asynchronous transfer. The reason is that after the cycle start packet, 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, the isochronous transfer is executed with priority over the asynchronous transfer.

In the general bus cycle shown in FIG. 18, a cycle start packet is transferred from the cycle master to each node at the start of cycle #m. As a result, each node adjusts the time, and after waiting for a predetermined idle period (isochronous gap), the node that should perform isochronous transfer performs arbitration and starts packet transfer. In FIG. 18, the channel e, the channel s, and the channel k are sequentially isochronously transferred.

After the operations from the 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.

When the idle time reaches the subaction gap in which asynchronous transfer is possible, a node that wishes to perform asynchronous transfer determines that it can start executing arbitration.

However, during the period in which the asynchronous transfer can be performed, a sub-action gap for starting the asynchronous transfer is obtained after the completion of the isochronous transfer until the time (cycle synch) at which the next cycle start packet should be transferred. Only when they are given.

In cycle #m in FIG. 18, two packets (packet 1 and packet 2) of isochronous transfer for three channels and then asynchronous transfer (including ack) are transferred. After the asynchronous packet 2, it is time to start the cycle m + 1 (cycle synch), and the transfer in cycle #m ends here.

However, the time (cy) to transmit the next cycle start packet during asynchronous or synchronous transfer operation
If cle synch is reached, the cycle start packet of the next cycle is transmitted after waiting for an idle period after the transfer is completed without forcibly interrupting the transfer. That is, when one cycle lasts for 125 μS or more, it is assumed that the next cycle is shorter than the reference 125 μS. As described above, the isochronous cycle can be exceeded or shortened on the basis of 125 μS.

However, the isochronous transfer is always executed if necessary every cycle to maintain the real-time transfer, and the asynchronous transfer may be transferred to the next and subsequent cycles due to the shortened cycle time.

The cycle information including such delay information is
Controlled by the master.

The above is the description of the IEEE1394 serial bus.

From this, as Example 1, as shown in FIG.
As an explanation when each device is connected by a serial bus cable 94, a printer device 101 operates as a direct print or a network printer. Reference numeral 102 denotes a VTR (camera-integrated digital video) connected to the printer 101 via a 1394 serial bus.
It is possible to print directly at 101 and to transfer video data and the like to other connected devices via the printer of 101. 103 is a personal computer (hereinafter referred to as PC) connected to the printer via a 1394 serial bus, and 104 is a PC and 1394
Scanner connected by serial bus. In addition,
The network of FIG. 2 is a group of devices as an example,
Further, the configuration may be such that the device is connected further before the PC 103 and the scanner 104. Also, connected devices are external storage devices such as hard disks,
Any device that can form a network with a 1394 serial bus, such as D or DVD, may be used.

The operation of the first embodiment of the present invention using the network configuration as shown in FIG. 2 will be described with reference to FIG.

Next, FIG. 1 (block diagram) will be described.

In FIG. 1, 1 is a printer main body, and 2 is a VTR.
Although the main body 3 is a magnetic tape as a recording medium, the present invention is not limited to such a tape, but may be another medium. 4
Denotes a recording / reproduction head, 5 denotes a reproduction processing circuit, 6 denotes a video decoding circuit, 7 denotes a D / A converter, 8 denotes an EVF for confirming a reproduced image or an image to be printed by a printer,
9 is an external output terminal, 10 is an operation unit for inputting instructions, 11 is a VTR system controller, 12 is a frame memory,
13 is a 1394 interface (I / F) section of the VTR, 14 is a selector for a plurality of types of data, 15 is a display processing circuit for enabling printer information to be displayed on the EVF, 16 is a video synthesizer,
17 is a 1394 interface (I / F) of the printer, 18
Reference numeral denotes an image processing circuit for performing an image forming process on an image to be printed by a printer, and includes a binarizing process, a color correcting process, and the like. 19 is a memory for forming image data as a print image, 20 is a printer head, 21 is a printer head
20, a driver for feeding paper, etc .; 22, an operation unit for controlling the operation of the printer; 23, a printer controller which is a control unit of the printer; The information generation circuit 25 is a data selector. SW1
Is a switch whose connection / disconnection is controlled by the printer controller 23.

Here, in FIG. 1, the VTR shows only the reproduction system. Further, the description of FIG. 1 is omitted to facilitate understanding of the description of the PC and the scanner shown in FIG.

Next, the operation of the block diagram 1 will be described step by step.

First, the video data recorded on the magnetic tape 3 is read out by the recording / reproducing head 4,
Performs a reproduction format process on the read video data. The read video data is converted into DCT (discrete cosine transform) and VLC as a band compression method for home digital video.
After being encoded and recorded by a predetermined compression method based on (variable length encoding), the signal is converted into an analog signal by the D / A converter 7 after the decoding circuit 6 performs a predetermined decoding process. The video signal is displayed on the EVF 8 or is analog-output from the external output terminal 9 to an external device.

When transferring desired video data to another node using the 1394 serial bus, the video data decoded by the decoding circuit 6 is temporarily stored in the frame memory 12, and 1394 I / F via data selector 14
13 and is transferred to the printer 1 from here in the isochronous mode. If the transferred video data is for direct printing, the printer 1 captures the video data into the printer. If the transferred video data is to be transferred to another node, the printer 1 passes through the 1394 I / F unit 17 to the target node. Will be transferred.

The input of a VTR instruction such as a VTR reproducing operation is performed from the operation unit 10. In the direct print operation, the instruction input to the printer is also performed.
Can be done from On the basis of an instruction input from the operation unit 10, the system controller 11 generates a control command to the printer according to a predetermined instruction input together with control of each operation unit such as control of a reproduction processing circuit of the VTR, and as command data. The data is transferred from the 1394 I / F unit 13 to the printer via the data selector 14.

Further, the operation status of the printer, a warning message,
Printer information data such as print image information is 1394I
After processing from the / F unit 13 through the data selector 14 to a displayable form by the printer information display processing circuit 15, the image is combined with the image currently displayed on the EVF by the image combiner 16 and displayed on the EVF 8, Display a message.

Alternatively, a configuration may be adopted in which both display information are selectively displayed by providing a switch circuit instead of the video synthesizer 16.

The data selector 14 and the data selector 25 of the printer 1 select each data to be input or output, and each data is sequentially input / output to a predetermined block while being distinguished for each data type.

Next, the operation of the printer 1 will be described.
Among the data input to the / F unit 17, the data selector 25 classifies the data according to the type of each data, the data to be printed is input to the image processing circuit 18, and the image processing circuit 18 performs image processing suitable for printing. Printer controller 23
The image formed as a print image in the read memory 19 in which the storage and the read are controlled is sent to the printer head 20 and printed. Driving such as head driving and paper feeding of the printer is performed by a driver 21, and operation control of the driver 21 and the printer head 20 is performed by a printer controller 23.

The printer operation unit 22 is used for paper feed, reset,
This is for inputting an instruction such as an ink check and a standby / stop of the printer operation, and the printer controller 23 controls each unit according to the input of the instruction. The switch SW1 is normally in a connected state. However, when a predetermined command is received from the printer controller 23, the operation unit is operated for a certain period or in a predetermined environment.
This is a switch for releasing the connection of all or a part of the key input from 22 to disable the input of all or specific commands. Such a switch S
Even without providing W1, the printer controller 23 may not be able to instruct and input such a specific command by itself.

Next, when the data input to the 1394 I / F unit 17 is data indicating a command for the printer 1 issued from the VTR 2 or the like, the data is transmitted from the data selector 25 to the printer controller 23 as a control command. The printer controller 23 controls each part of the printer.

The printer information generating section 24 outputs a message indicating whether the printer is in an operating state and whether printing is completed or started, a message indicating a paper jam, a malfunction, the presence or absence of ink, and the like. After the image information and the like are input to the data selector 25 as printer information, the data can be output from the 1394 I / F unit 17 to the outside. Based on the output printer information, the printer information display processing circuit 15 performs display processing on the information that can be displayed on the EVF in the VTR 2 as described above.

By viewing the message and the print image information displayed on the EVF 8 based on the printer information, the user inputs a command to the printer 1 from the operation unit 10 so as to take appropriate measures. By transmitting control command data via a bus, it is possible to control the operation of each unit of the printer 1 and control the print image in the image processing unit 18 under the control of the printer controller 23.

As described above, video data, various command data, and the like are appropriately transferred to the 1394 serial bus connecting the VTR 2 and the printer 1.

The transfer format of each data transferred from the VTR 2 is based on the above-mentioned specification of the 1394 serial bus, and video data (and audio data) are mainly transferred as iso data on the 1394 serial bus as iso data. The command data is transferred as asynchronous data by the asynchronous transfer method. However, depending on the type of data, it may be more convenient to send the data by the asynchronous transfer method than by the isochronous transfer in some cases. In such a case, the asynchronous transfer method is used.

The printer information data transferred from the printer 1 is transferred as Async data by the asynchronous transfer method. However, when transferring print image data with a large amount of information, it may be transmitted as iso data by the isochronous transfer method.

The above is the description of the block diagram of FIG. When a network such as that shown in FIG. 2 is formed by the 1394 serial bus, both the VTR 2 and the printer 1
Based on the specifications of the C and 103, the scanner 104, and the 1394 serial bus, bidirectional transfer of each data is possible.

When the direct printing of the video data from the VTR 2 to the printer 1 is realized by adopting the configuration as shown in the block diagram and FIG. 1, the operation of the printer 1 can be generally controlled by operating only the VTR 2. Is desirable, and is a possible configuration in FIG. Therefore, during the direct print operation, each part of the printer 1 can be controlled by operating only the VTR 2, and in the present invention, the instruction input from the operation unit 22 for the operation of the printer 1 is completely or a specific command input is prohibited at this time. The setting is made so that various malfunctions during direct printing can be eliminated by performing (rejecting). For this purpose, the printer 1 receives the data (Async) on the 1394 bus indicating the start of direct printing from the VTR 2 before transferring the video data to be directly printed,
This can be realized by opening the number 1.

The direct print operation (mode)
Mutual recognition between the start VTR 2 and the printer 1 starts with the transmission and reception of the direct print start data, and the VTR 2
Direct print end data on the 1394 bus (Asyn
c) transferred and received by printer 1 or VTR 2
The direct print mode is set to end when the connection of the 1394 serial bus connecting the printer 1 and the printer 1 is released, and the printer controller 23 restarts the connection of the switch SW1 when judging the end of the direct print mode. I do. The disconnection of the 1394 serial bus connection can be automatically determined by the printer device by the occurrence of a bus reset of the 1394 serial bus and the construction of a new bus configuration.

As an example, a switch as shown in FIG. 5 is attached as one of the switch devices of the operation unit 10 of the VTR 2 for instructing the start / end of the direct print and outputting a command. In FIG. 5, "OFF"
Is a power-off state, "photographing" is a position for recording video and audio, and "reproduction" is a position for normal reproduction. "Direct print" is a position for performing a direct print mode. When the switch is switched to this position, the VTR 2 transmits a direct print start command to the printer, and when shifted to another position, a direct print end command is issued. To send. The central "PUSH" key may also serve as a trigger for shooting, a command input switch for arbitrary selection, a switch for starting transmission of video data including during direct printing, and the like.

Further, even if a command for indicating the start / end of direct printing is not transmitted separately from the video data using the switch as shown in FIG. 5, the transmission method of the 1394 serial bus can be used as described above. , When video data is transferred from the VTR 2 to the printer 1, it may be determined from the header information of the packet containing the video data, that the direct print operation is performed, and that the direct print operation is performed.

FIG. 6 is a flowchart showing the sequence of prohibiting the instruction input of the operation unit 22 of the printer in the direct print operation mode, including the flow of the operation of the VTR 2 and the printer 1 at the time of direct printing.
explain.

First, at step S1, since the printer operation unit 22 is in a state in which an instruction can be input in the normal mode, the switch SW1 is in a connected (ON) state. Here, as step S2, when the user shifts to the direct print mode, a direct print start command is transmitted from the VTR 2 in the manner described above. The transmitted start command is transferred as an asynchronous packet through the 1394 serial bus, and when the printer 1 receives this command in step S3, the printer controller 23 starts the direct print mode and opens (OFF) the switch SW1 in step S4. .
Thus, during the direct print mode, the switch SW1 and the operation unit 22 and the printer controller 23 are configured to block, disable, or ignore all instruction inputs from the printer operation unit 22 or only specific instruction inputs.
By configuring any of the functions described above, it is possible to disable, disable, or ignore a specific instruction input.

When the start command is not received in step S3, the connection of the switch SW1 is maintained in the normal mode until the start command is received.

In parallel with the process of shifting the printer 1 to the direct print mode, the VTR 2 selects a video to be printed by the user, and if any one video is designated for transfer in step S5, the process proceeds to step S6. After transferring the specified video data by isochronous (or asynchronous) packet transfer using the 1394 serial bus, the process proceeds to step S9. If any video is not specified in step S5, the process proceeds to step S9 without performing video data transfer.

If the printer 1 receives the video data packet-transferred on the 1394 serial bus in step S7, the printer 1 prints the received video data in a predetermined sequence in step S8, and then proceeds to step S7. Return and receive the next video data.

In the VTR, in step S9, the user selects whether to end the direct print mode or to designate and transfer another image without ending. If it is determined in step S9 that another video is to be specified without terminating the process, the process returns to step S5, and an arbitrary video can be specified again. Here, the image designation in step S5 and the transfer of the designated image data in step S6 are repeatedly performed through step S9.
In particular, when printing a plurality of sheets, the transfer processing is performed while controlling the output while maintaining the balance with the operation processing of the printer 1.

When the user selects to end the direct print mode in step S9,
In step S10, a direct print end command is transmitted, and the end command data is transferred to the 1394 serial bus in an asynchronous packet. Then, the direct print mode of the VTR ends.

If the printer 1 does not receive the video data to be printed from the VTR 2 in step S7,
The process proceeds to step S11, where a direct print end command is received. If the direct print end command from the VTR 2 has not been received in step S11, the process returns to step S7 to receive video data from the VTR 2 to be printed while maintaining the direct print mode.

In step S11, VT is set as step S10.
When the direct print end command data transferred by packet from R2 is received, the printer controller 23 connects (ON) the switch SW1 in step S12 to end the direct print mode in the printer 1 and return to the normal operation mode. To control. Thus, the direct print mode of the VTR 2 and the printer 1 ends.

The above is the description of the flowchart of FIG.

If the cable connection of the 1394 serial bus connecting the VTR 2 and the printer 1 is disconnected for some reason during the direct print mode, as described above, the printer is reset due to the occurrence of a bus reset and the new network configuration. Since the printer 1 can automatically determine that the VTR 2 is not connected, the switch SW1 is connected as the end of the direct print mode, and control is performed so as to return to the normal mode. As a result, the operation as a network printer can be resumed.

The above is the description of the first embodiment.

<Embodiment 2> In Embodiment 2, the present invention is described with reference to FIG.
A description will be given of a case where the digital camera is used instead of the VTR 102.

FIG. 4 is a block diagram showing a case where the digital camera and the printer according to the present invention are connected by a 1394 serial bus cable.

In FIG. 4, reference numeral 1 denotes the printer main body described in the first embodiment, 61 denotes a digital camera main body, 62 denotes an image pickup section, 63
Is an A / D converter, 64 is an image processing unit, 65 is an image encoding / decoding circuit, 66 is a memory recording / reproducing unit for recording / reproducing images, 67 is a D / A converter, and 68 is an EVF as a display unit.
Reference numeral 69 denotes an operation unit of the digital camera, 70 denotes a system controller of the digital camera, 71 denotes a data selector, 72 denotes a 1394 I / F unit of the digital camera, 73 denotes a display processing circuit for displaying printer information, and 74 denotes a video synthesizer.

The printer 1 is the same as that described in the first embodiment, except that a decoding circuit 26 is provided between the data selector 25 and the image processing circuit 18 in the printer 1.

The image encoding / decoding circuit 65 of the digital camera 61 encodes a still image according to the well-known JPEG method as an encoding technique.

Next, the operation of the block diagram 4 will be described step by step.

First, at the time of recording by the digital camera 61,
The image data picked up by 62 is digitized by an A / D converter 63, and image data is processed by an image processing unit 64 so as to be an image suitable for display. One of the outputs of the image processing section 64 is converted into an analog signal by the D / A converter 67 as a video being captured, and is displayed by the EVF 68. The other output is encoded by the encoding circuit 65 according to the JPEG method, and is recorded in the memory by the memory recording unit 66.

At the time of reproduction, a desired image is read from the memory by the memory reproduction section 66. At this time, selection of a desired image is selected based on information input from the operation unit 69, and is controlled and read by the system controller 70. The image data reproduced from the memory is JPEG-compressed by the decoding circuit 65 and processed by the image processing unit 64 and the D / A converter 67, and can be displayed on the EVF 68.

Alternatively, after the desired image data is reproduced from the memory, when the desired image data is to be transferred to a PC or the like of another device connected by a direct print or a 1394 serial bus, the data is transmitted from the 1394 I / F unit 72 via the data selector 71. It is transferred using a 1394 serial bus. At this time, the image data reproduced from the memory reproducing unit 6 is output as it is as data encoded by the JPEG method, and is decoded in the printer at the time of direct printing.

The operation of the printer 1 is the same as that of the first embodiment, and a description thereof will be omitted. The decoding circuit 26 will be described here. The image data transferred from the digital camera 61 is decoded by the decoding circuit 26 into JPEG compressed data using software. In the decoding circuit 26, the RO
M that holds a JPEG decoding program file in M, or using decoding data transmitted from the digital camera 2 together with the compressed image data,
The decoding process is performed by a circuit only in the printer device or by software by the CPU.

By transferring image data compressed by the JPEG system from the digital camera to the printer and decoding it in the printer, the transfer efficiency is higher than that of converting the data to uncompressed data before transferring. Since JPEG decoding can be performed by software, even if a decoder is provided in the printer itself, there is no problem in terms of cost and it is convenient. In the decoding circuit 26, a JPEG decoding circuit (board) may be provided as hardware decoding.

Instruction input to each section of the digital camera is performed from the operation section 69, and instruction input to the printer can also be performed from the digital camera operation section 69 during a direct print operation. Based on the instruction input from the operation unit 69, the system controller 70 controls each operation unit including the control of the reproduction processing circuit of the digital camera,
Further, depending on the input of a predetermined instruction, a control command to the printer is generated, and the data selector 71 is used as command data.
Is transferred from the 1394 I / F unit 72 to the printer.

Further, the printer operating status, warning message,
Printer information data such as print image information is 1394I
/ F section 72, through a data selector 71, and processed by a printer information display processing circuit 73 into a displayable form, and then synthesized by an image synthesizer 74 so as to be synthesized with an image currently being displayed on an EVF and displayed on an EVF 68. Display a message. Alternatively, a configuration may be adopted in which both display information are selectively displayed by providing a switch circuit instead of the video synthesizer 74.

The data selector 71 selects each data so as to be input / output to / from a predetermined block while sequentially distinguishing each data for each data type.

The transfer format of each data transferred from the digital camera 62 is based on the above-mentioned specification of the 1394 serial bus, and the image data is mainly transferred as Iso data on the 1394 serial bus by the isochronous transfer method. Are transferred as asynchronous data by the asynchronous transfer method. However, in some cases, it is more convenient to send data using the asynchronous transfer method than to perform isochronous transfer. In such a case, the asynchronous transfer method is used.

The above is the description of the block diagram of FIG. Note that if a network is configured with a device other than the printer 1 using the 1394 serial bus, the digital camera 61 also transmits data to each of the printer 1 based on the specifications of the PC or 103 or the scanner 104 and the 1394 serial bus. Transfer is possible.

By realizing direct printing of image data from the digital camera 61 to the printer 1 by constructing a block diagram as shown in FIG. 4, each part of the printer 1 can be controlled by operating only the digital camera 61. In this embodiment, at this time, all or an instruction input from the operation unit 22 for the operation of the printer 1 is prohibited or a specific command input is prohibited (rejected), thereby eliminating various malfunctions during direct printing. Make settings that allow you to do so. For this purpose, a switch as shown in FIG. 5 is provided as a part of an instruction input key in the operation unit 62 of the digital camera 61, and before the transfer of the video data to be directly printed, the digital camera 61 transmits the data on the 1394 bus indicating the start of direct printing in advance. The transmission of the (Async) packet can be realized by the printer 1 receiving the packet and opening the switch SW1 under the control of the printer controller 23.

Alternatively, as in the first embodiment, the operation unit
22, it is also possible to invalidate some operation information by software processing of the printer controller 23.

The direct print operation (mode)
The mutual recognition between the digital camera 61 and the printer 1 at the start is
Beginning with sending and receiving this direct print start data,
Based on the instruction input from the switch of FIG. 5 provided in the digital camera 61, the direct print end data is transferred from the digital camera 61 to the 1394 bus (Async) packet and received by the printer 1, or the communication between the digital camera 61 and the printer 1 is performed. The direct print mode is set to end when the connection of the connected 1394 serial bus is released, and the printer controller 23 restarts the connection of the switch SW1 when judging the end of the direct print mode. The disconnection of the 1394 serial bus connection can be automatically determined by the printer device by the occurrence of a bus reset of the 1394 serial bus and the construction of a new bus configuration.

The systematic operation of the printer 1 and the systematic operation of the digital camera 61 and the printer 1 during direct printing according to the present invention are the same as those described in the first embodiment. 6, the description is omitted here.

The above is the description of the second embodiment.

<Other Embodiments> Normally, a visual interface (a so-called GUI) using a monitor of a PC is used.
Although the printer is controlled, all functions cannot be monitored during direct printing, such as the GUI, so only the functions that can be supported by the camera can be operated, and only the functions that cannot be monitored can be disabled. May be.

As described above, according to the present embodiment,
The print processing that the user prefers to perform can be quickly performed by performing the direct print processing.

In addition, when a command is received from a camera or a VTR during a direct print operation and a print operation is performed, a command input by an instruction unit provided in the printer is inhibited, thereby preventing a malfunction during direct print. . Alternatively, malfunction can be reduced.

In the direct print using the 1394 serial bus, data communication for image print output can be performed without passing through a PC, so that quick processing can be performed without being affected by the operation state of the PC. The load on the PC caused by data processing can be eliminated.

By disabling the function (only) for which the operation state cannot be confirmed, it is possible to reduce the malfunction of the printer and to provide an excellent user interface even during direct printing.

In this embodiment, an interface conforming to the 1394 standard has been described as an interface. However, the present invention is not limited to this, and other interfaces, for example, those using infrared rays or those using radio waves may be used.

The printer may be a printer using an ink jet or a printer using an electrophotographic system.

[0188]

According to the present invention, arbitration can be performed without instructing operations between two nodes.

Further, according to the present invention, a command from a camera or a VTR is accepted at the time of direct printing and command input by an instruction unit provided in the printer is prohibited, so that there is no malfunction and the usability is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a printer and a VTR to which the present invention is applied.

FIG. 2 is a diagram showing an example of a network when implementing the present invention.

FIG. 3 shows a conventional digital camera, PC, and printer connected to a PC.
FIG. 4 is a block diagram showing a configuration when the connection is made mainly.

FIG. 4 is a block diagram of a printer and a digital camera to which the present invention is applied.

FIG. 5 is an example of a switch used in the present invention.

FIG. 6 is a flowchart showing the flow of operations of a VTR and a printer to which the present invention has been applied.

FIG. 7 is a diagram showing an example of a network configuration connected using a 1394 serial bus.

FIG. 8 is a diagram showing components of a 1394 serial bus.

FIG. 9 is a diagram showing an address map of a 1394 serial bus.

FIG. 10 is a sectional view of a 1394 serial bus cable.

FIG. 11 is a diagram for explaining a DS-Link coding scheme.

FIG. 12 is a diagram for explaining a topology setting for determining an ID of each node on the 1394 serial bus.

FIG. 13 is a diagram for explaining arbitration on a 1394 serial bus.

FIG. 14 is a basic configuration diagram showing a temporal state transition of asynchronous transfer.

FIG. 15 is a diagram showing an example of a format of an asynchronous transfer packet.

FIG. 16 is a basic configuration diagram showing a temporal state transition of isochronous transfer.

FIG. 17 is a diagram showing an example of the format of a packet for isochronous transfer.

FIG. 18 is an example of a bus cycle showing a state of a packet transferred on an actual bus in a 1394 serial bus.

FIG. 19 is a flowchart showing a flow from a bus reset to a determination of a node ID.

FIG. 20 is a flowchart showing the flow of parent-child relationship determination in a bus reset.

FIG. 21 is a diagram showing a state after a parent-child relationship is determined in a bus reset.
The flowchart figure which shows the flow until a node ID is determined.

FIG. 22 is a flowchart for explaining arbitration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer apparatus 2 VTR 10 Operation part (VTR) 11 System controller (VTR) 22 Operation part (printer) 23 Printer controller 24 Printer information generation part 62 Operation part (digital camera) 70 System controller (digital camera) SW1 switch

Claims (11)

[Claims] A first node having an image display monitor and an operation unit; and a second node having an operation unit without an image display monitor, wherein the first node and the second node are provided. Is a system that communicates with DS-Link via DS-Link, and has arbitration means for arbitrating an instruction from the operation unit of the first node and an instruction from the operation unit of the second node. Data communication system. 2. The data communication system according to claim 1, wherein said arbitration means prioritizes operation of said first node over operation of said second node. 3. The data communication system according to claim 1, wherein said arbitration means prioritizes operation of said second node over operation of said first node. 4. The data communication system according to claim 1, wherein said first node and said second node are connected by a serial bus. 5. The data communication system according to claim 4, wherein said serial bus is a bus according to the 1394 standard. 6. The data communication system according to claim 1, wherein said second node is a printer. 7. The data communication system according to claim 6, wherein said arbitration means invalidates an operation of an operation unit of said printer during printing by said printer. 8. A system comprising a video device having an image display monitor and an operation unit, and a printer having an operation unit, wherein an instruction from the operation unit of the video device and an instruction from the operation unit of the printer are provided. Arbitration means for arbitrating with the print system. 9. The video device transmits video data to an Isoch
9. The print system according to claim 8, wherein the print system transmits the status information by a robust transfer and receives the status information of the printer by an asynchronous transfer. 10. The print system according to claim 8, wherein information indicating a status of said printer is displayed on said monitor means. 11. A data communication device forming a first node and a second node of the data communication system.