JP2000174773A - Data communication equipment and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the acquirement communication process of self- identification information by giving self-identification information of data communication equipment in a topology establishment process. SOLUTION: In a process allocating ID of the respective nodes of a network, the node to which ID is given broadcasts ID information to the network (S307). The whole capacity of self-identification information, data capacity which can be received, a peculiar identification code and at least one piece of information among classification information of a supplied function is added to ID information and they are transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication apparatus and a control method thereof, and more particularly, to a data communication apparatus for reconstructing a topology according to a change in a network configuration and a control method thereof.

[0002]

2. Description of the Related Art As the performance of computers has been improved, peripheral devices such as printers have become more sophisticated and faster.
In the past, computers and home electric appliances were clearly separated from each other. However, computers are becoming home electric appliances, and home electric appliances are being digitized, and an environment for forming a system in close cooperation with a computer is being prepared. Along with this, the range of users has expanded, and it has become an important issue to establish an environment where even users who do not know much about computers can easily connect and use computers and peripheral devices.

Hitherto, RS-232C, IEEE 1284 (Centronics interface) and the like have been provided as standard buses for computers. More recently, SCSI (Small Computer Sys.) For the purpose of adding peripheral devices such as hard disks.
Interfaces such as PCMCIA have become widespread for the purpose of adding peripheral devices for portable personal computers and the like.

[0004] RS-232C is a simple interface but has a low transfer capacity. IEEE 1284 is standardized with extended functions, but is almost exclusively a printer interface. SCSI is also SCSI-
2, SCSI-3, but it is difficult to set.
Not a user-friendly bus. Except for the SCSI, it is a single-drop bus, cannot simultaneously connect a plurality of peripheral devices, has large cables and connectors, and has a low degree of freedom in wiring.

In order to overcome the disadvantages of the conventional bus, a new USB (Universal Serial) has been newly developed.
l Bus), IEEE 1394 High perf
New buses such as the Ormance Serial Bus have been standardized. The characteristics of these buses are plug-and-play, multi-drop buses compatible with high-flexibility topologies that were not available in conventional buses, small cables and connectors, easy wiring, and constant This is to realize isochronous transfer in which the amount of data transferred in time is guaranteed. As a result, DVDs (Digital Versatile Diss) which are expected as peripheral devices in the future
k) It can support video streams used in drives and the like, and is suitable for integration between computers and home electric appliances.

[0006] Among them, IEEE 1394 has a higher transfer speed than USB, so that a high-speed HDD (Hard Dis-
It is also being considered for use as an interface of k.

[0007] In IEEE1394, each connected node operates by being mapped to a 64-bit wide address that has taken over the IEEE1212 standard. The first 10 bits of the 64-bit address are called busID and are used for bus identification. The next 6 bits are called nodeID and are used to identify each device. Remaining 48b
It becomes an internal address space that can be used in each device. The busID can take a value from 0 to 1023, in which 1023 (0 × 3FF) is a local bus,
That is, it shows the bus to which the device is directly connected. n
modeID can be used from 0 to 63, but 6
3 (0 × 3F) is reserved as a broadcast, and designates all nodes connected to the bus. Therefore, a maximum of 63 devices can be connected to one local bus.

The 48-bit address space in each node is managed by being divided into the first 20 bits and the remaining 28 bits. 0x00000-0FF of the first 20 bits
The space of the FFD is called a memory space. 0xFFF
The FE space is called a private space and can be used freely for closed access within the device. 0x
The space of FFFFF is called register space, and is used for information exchange between devices.

The first 512 bytes of the register space have a CSR (Control and Status Reg).
The register which is the core of the (ister) architecture is mapped. The serial bus register is mapped in the next 512-byte space, and the Configuratio is stored in the next 1024-byte space.
There is an nROM, and the remaining space is defined as a device-specific register space.

In IEEE 1394, memory space mapping is automatically performed on connected nodes. The timing is when a bus reset signal is issued. The bus reset signal is issued when the topology of the bus changes, such as when a new node is connected to the bus or when a node is taken out of the bus. In some cases, a bus reset signal is issued from a connected node. When the bus reset signal is generated, the topology information of the bus used previously is cleared, and a configuration sequence of new topology information is performed. At this time, a packet called a SelfID packet is sequentially transmitted by broadcast from each node,
Build a new topology.

The SelfID packet contains a plurality of pieces of self-identification information, and the information is used to enable communication between the nodes. FIG. 25 shows the data format of the SelfID packet.

[0012] In IEEE1394, all packets are defined in quadlet (32 bit) units.
A (packet # 0), b in the SelfID packet
Two formats of (packet # 1, # 2, # 3) are defined, and depending on the number of ports of the node, only a or a combination of a and b is set. As shown in FIG. 9, the number of ports (pX) determines the number of packets of b following a and the value of n. If the number of ports is 16, pack
et # 0, packet # 1, and packet # 3 are transmitted.

One horizontal row in FIG. 8 is 1 quadlet,
The transmission is performed from the upper row in the direction from the left (No. 31) to the right (No. 0). The first bits 31 and 30 are identifiers, p
The hy_ID field is the nodeI of the transmitting node.
D, next L is a Link_active field of the node, gap_cnt is timing for bus arbitration,
sp is the transfer rate of the bus in the PHY_SPEED field, del is the delay time of the bus in the PHY_DELAY field, c is the presence or absence of the bus management capability of this node in the CONTENDER field, and pwr is POWER_C.
In the LASS field, power information of this node, p0 to p
2 and pa to ph (p3 to p26) indicate the port connection state, i indicates an initialized_reset field, and if set, indicates that this node has issued a bus reset. M indicates a more SelfID of this node in the more_packets field. packet
(Extended SelfID packet) is continued, and n is an Extended
Indicates the sequence number of the fID packet (0 to 2 are defined), and r indicates a reserved field in a reserved field.

Although it is possible to perform communication using only the self-identification information defined here, it is not actually possible to perform efficient communication only with the information provided here. For example, it is unknown how much the capacity of the CSR register of each node is. Also, the size of a packet that can be processed by the node is determined by max_rec in the CSR.
Must refer to the value of

Further, since phy_ID is a value that may change with a change in topology, a node cannot be specified only by phy_ID. Node_vendor_id, c included in CSR for node identification
Since the information of the hip_id is required, a communication process for reading the value is necessarily required.

[0016] Further, since only the defined self-identification information does not tell what services each node can provide, each node has a communication process for obtaining detailed information on all nodes. Will be needed.

[0017]

As described above, the prior art has the following problems.

(1) Since the capacity of the CSR of the node is unknown, it is not known to which space of the CSR the information exists. Therefore, in controlling a communication process for obtaining CSR information, it is not possible to efficiently perform preparations such as securing a memory for storing information.

(2) Since the buffer size of the node is unknown, a communication process for reading the value of max_rec in the CSR is required.

(3) After a change in the topology, all nodes are required to identify all nodes.
A communication process for acquiring the values of de_id and chip_id is required.

(4) The user does not know what service the node provides. Therefore, in order to search for a node that can provide a service that can respond to an application request, detailed information on the CSRs of all nodes is required, and a communication process for acquiring the information is required.

The present invention has been made in view of the above problems, and a first object of the present invention is to simultaneously determine the capacity of node self-identification information for all nodes in the process of establishing a topology. By providing the notification, a topology establishment process capable of efficiently performing a subsequent communication process for acquiring self-identification information is provided.

A second object is to simultaneously notify all nodes of the capacity of the communication data that can be processed by the nodes in the topology establishment process, so that the subsequent communication process can be performed efficiently. Provides a possible topology establishment process.

A third object of the present invention is to simultaneously notify all nodes of unique id information that can identify a node in the topology establishment process, so that all nodes are notified at the end of the topology establishment process. Provide a identifiable topology establishment process.

The fourth object is to classify the functions provided by the nodes in advance, and to notify the classification information to all the nodes simultaneously in the topology establishment process, thereby providing the necessary functions. By performing only the communication process for acquiring the self-identification information of the failed node, a topology establishment process is provided in which unnecessary node information is not required.

[0026]

Means for Solving the Problems To achieve the above object, a data communication apparatus and a control method thereof according to the present invention have the following configurations. That is, connected to the network,
A data communication apparatus for reconstructing a topology in response to occurrence of a change in the topology of the network, means for executing a predetermined procedure with the connected data communication apparatus to reconstruct the topology, and reconstructing the topology. Later, the self-identification information including at least one of the total capacity of the self-identification information, the receivable data capacity, the unique identification code, and the classification information of the function to be provided is transmitted to the node connected to the network. Means for transmitting to the user.

[0027] Preferably, said network is I
It is composed of an IEEE 1394 serial bus.

According to the above configuration, the capacity for acquiring detailed self-identification information is specified at once for all nodes in the topology establishment process.

Further, with the above configuration, the receivable data capacity is specified for all nodes at once in the topology establishment process.

Further, with the above configuration, the unique identification code that can identify itself is specified at once for all nodes in the topology establishment process.

Further, with the above configuration, the classification information of the function to be provided is specified at once for all nodes in the topology establishment process.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 2 shows a configuration example of a general IEEE 1394 node. The nodes include a physical layer 201, a link layer 202, a transaction layer 203, a serial bus manager 204
And four functional blocks. An application layer 205 is provided thereon, and each layer operates according to a request from the application layer 205.

The function of the physical layer 201 is to convert a logical symbol used in the link layer 202 into an electric signal defined by IEEE1394, and conversely, to convert an electric signal back into a logical symbol usable in the link layer. . Providing a bus arbitration service to ensure that only one node transfers data at a time. Therefore, driver / receiver, signal level detection, arbitration function, bus initialization sequencer, connector / media (cable, etc.), DS
An encoding / decoding function for LINK encoding and the like are included.

The link layer 202 controls cycle control for isochronous transfer (this function is optional) and packet transmission / reception. In addition, there are a function of encoding / decoding a CRC code for error checking of a transaction, a function of packetizing transmitted / received data, a function of unpacketizing data, and the like.

In the transaction layer 203, the IEEE
Three transactions defined in E1394,
Controls read, write, and lock transactions.

The serial bus manager 204 has a node controller as an essential function. The isochronous resource manager and the bus manager provide a bus management function that cannot be provided only by the node controller. These features are optional. The node controller supports the CSR function specified by IEEE1212 and the Configura added by IEEE1394.
The configuration and management of the operation of the individual nodes can be performed using the standard CSR composed of two of the content ROM functions. Using the isochronous CSR, the isochronous resource manager can manage the allocation of the isochronous band, the allocation of the channel number, the selection of the cycle master, and the like. The bus manager performs power management of the bus, maintenance of the speed map, maintenance of the topology map, and optimization of the bus based on information obtained from the topology map.

In IEEE 1394, when the connection status of an arbitrary port of a node on the bus changes, such as when a node is added to the bus, the existing topology information is cleared and new topology information is replaced. The bus must be initialized to build. Nodes connected on the bus include a leaf (Leaf) and a branch (Bra).
nch) and a route (Root).
A leaf node is a node in which only one port of the node has a valid connection, and a branch node is a port having valid connections in a plurality of ports. The root node is a node that controls bus arbitration, and only one is selected on the bus. However, it may be either a leaf or a branch.

Referring to FIGS. 4 to 21, after the bus is initialized,
A sequence until a bus topology is established and data can be transmitted and received will be described. FIG. 4 shows a state in which the bus is connected to five nodes (Nodes A to E) and is in a state immediately after the initialization of the bus. The physical connection between nodes is indicated by two arrows, which is an abstract representation of the signal state of the line. That is, the signals in the two directions are not using separate wire pairs. Actually, both signals use wire pairs, and the received signal is determined by giving priority to “0” over “Z” and “1” over “0”. FIG. 4 shows a state in which a bus reset signal has been issued and all topology information has been cleared. At this point, no node number has been individually assigned.

Here, each node detects the connection state of the port, and “off” is given to the port not connected.
And recognizes whether it is a leaf node or a branch node. Node A has five ports, but is connected to port # 0
Since it is only a leaf node, it is recognized as a leaf node. Although the node B has two ports, all the ports are connected, so that it is recognized as a branch node.

When the initialization of the bus is completed, the tree is identified. This process converts the bus network topology into a single topology. One root node is designated from the nodes connected to the bus, and the other nodes determine the port direction and assign a label.
The port closer to the root node is called the parent
t) "port, distant port to" child "
Ports are assigned, and labels p and ch are assigned to each port. This process will be described with reference to FIGS.

First, as shown in FIG. 5, all the leaf nodes (Node A, C, E) assign a label p with the only connected port as a “parent” port, and Pa to a node that seems to be
Send rent_notify.

Node B and D are, as shown in FIG.
Allocate a label ch as a “child” port to the port that has received the arent_notify signal,
At the same time, it sends a child_notify signal to that port. Next, a label p is assigned to a port considered to be a “parent” port, and parent_not is assigned.
Send an ify signal. Where parent_not
Ify signal collisions occur and the route competition process begins. In the figure, a collision of a parent_notify signal occurs between Port # 1 of NodeB and Port # 0 of NodeD.

As shown in FIG. 7, a leaf node (Nod
eA, C, and E) cancel the parent_notify signal upon receiving the child_notify signal.
NodeB and D, which are candidates for the root node, are once p
Cancel the arent_notify signal.

Then, as shown in FIGS. 8 and 9, after starting a timer or waiting for a time determined at random, each node checks the state of the contending port to determine whether it is in the idle state. , The parent_notify signal is received. If the port is idle,
The parent_notify signal is transmitted again. Conversely, when a parent_notify signal is received, a child_notify signal is transmitted. In this example, NodeD transmits a parent_notify signal first, and NodeB receives child_notify
This shows a case where a tiffy signal is being transmitted.

When receiving the child_notify signal, the NodeD receives the parent_notify signal as shown in FIG.
Cancel the transmission of the notify signal and the child_notify signal. Thereafter, the NodeB cancels the transmission of the child_notify signal as shown in FIG. With the above processes, the tree recognition process ends.

Next, a physical that is unique to each node
Enter the _ID determination process. As shown in FIG. 12, the root node (NodeB) transmits a grant signal to the port with the lowest port number, and sends data to the other ports.
Start by sending a _prefix signal. At this time, the value of self_ID_count is 0.

When the node receives the grant signal,
Propagate the grant signal to the lowest numbered port in the node that has not yet been identified. If there is no port for transmitting the grant signal, that is, Nod in FIG.
In the example of eA, the current value of self_ID_count is set as node_ID number, and the self-identification information Sel
Preparation for generating and transmitting the fID packet is started.

The transmission of the self-identification packet starts as shown in FIG.
As shown in the figure, data_prefi from NodeA
The root node is informed by the transmission of the x signal. Upon receiving the data_prefix signal, the root node cancels the grant signal. Further, the NodeD propagates the received data_prefix signal to the child nodes NodeC and E. At this point, all d
Since the data_prefix signal is directed away from NodeA, it becomes possible to transmit a SelfID packet. The phy_ID at this time is 0.
Since the SelfID packet is transmitted by broadcast, it is received by all nodes on the bus.

The format of the SelfID packet is shown in FIG. 25 and FIG. The SelfID packet in the present invention is transmitted after adding the additional information shown in FIG. 1 following the SelfID packet (FIG. 25) defined in IEEE1394. Here, the Confirmation
Add the size of the ROM and the buffer size that the node can receive. Configuraton_ROM_ in FIG.
The length field has an information amount of 8 bits. Here, the Configur that each node has
the size of the ationROM in quadlet units (4b
yte). Therefore, in this example, 1 Kbyte
It is possible to express up to the size of e. Furthermore, m
The ax_rec field stores the maximum load size of a packet addressed to this node, that is, the size of the reception buffer. FIG. 3 shows a correspondence table between the value of the max_rec field and the reception buffer size. max_rec is 0x3
When the value is, the size is 16 bytes. This max
_Rec field is the Bus_Inf in the CSR
Takes the same value as the max_rec field of o_Block.

The information of Node A in this example is as follows.

Phy_ID: value of self_ID_count (0x
00) Link: Active (0x1) gap_cnt: PHY_CONFOGURATIO
N. The value of gap_count. Here, it is set to 0x3F.

Sp: Supports up to 400 Mbps (0x2) del: 144 ns or less (0x0) C: Becomes a bus manager and an isochronous resource manager (0x1) pwr: Does not require power supply (0x0) p0 to p4: Only p0 is a parent node Connection Configuration ROM: 16 quadl
et max_rec: 512 bytes. The value of the Self ID packet of Node A at this time is 0x807F8895 0x7F80776A 0x80814001 0x7F7EBFFE 0x80B10800 0x7F4EF7FF. Note that the even rows are logically inverted values of the odd rows.
The SelfID packets in the fifth and sixth rows are the newly added portions shown in FIG. By adding this information, the other nodes are able to configure NodeA's configurat
The data length and buffer size of the ion ROM can be known in the process of establishing the topology.

When the transmission of the Self ID packet of Node A is completed, as shown in FIG.
Send the ne signal to the parent node. identity_done
The parent node that has received the signal assigns a ch-i label to the port. All nodes are self_ID_c
The value of “out” is increased to “1”. Further, as shown in FIG. 15, the root node transmits a grant signal to the port with the lowest number to which no ch-i label is assigned, and transmits data-prefix to the other ports. Here, a data_prefix signal is transmitted to Node D connected to port 1.

As shown in FIG. 16, since there is a node which has not been identified yet, the NodeD sends a grant signal to the port with the lowest number and a data_data to the other ports.
Send a prefix signal.

Since there is no unidentified child node in the NodeC that has received the grant signal, a data_prefix signal is transmitted as shown in FIG.
This data_prefix signal is propagated to the root node. Next, NodeC sets the current self_ID_c
The value of “out” is set as a node_ID number, and
SelfID information is packetized and SelfID
Send a packet.

When the transmission of the Self ID packet of the Node C is completed, as shown in FIG.
Send the ne signal to the parent node. identity_done
After receiving the signal, the NodeD assigns a ch_i label to the port, confirms that the port has been identified, and then transmits data_pref from the port connected to the parent node.
The ix signal is canceled, and a data_prefix signal is transmitted to the port to which the NodeC is connected.
All nodes set the value of self_ID_count to 2
Move on.

The root node (NodeB) is data_
Confirms that the prefix signal has been canceled and the bus has become idle. However, since the port has not been identified, the grant signal is transmitted to the lowest-numbered port that has not been identified again as shown in FIG. . NodeD receiving the grant signal from the root node,
Since there is a port that has not been identified yet, as shown in FIG.
Transmit the ant signal.

Hereinafter, until all ports are identified,
By repeating the same process described previously, finally all ports are identified and the bus topology is established, as shown in FIG.

In the present invention, the size of the Configuration ROM is added to the self-identification information in the bus identification process, so that the C
It is possible to omit that each node individually performs the operation of knowing the buffer size of the node existing in the SR. At the same time, the same effect can be obtained by adding buffer size information. Since the information added here is essential information for performing communication, the effect is expected to increase as the number of nodes connected to the bus increases.

<Sequence of Determining Node ID> Reconstruction of topology and node ID after bus reset described above
Focusing on one node, the decision process
This will be described with reference to flowcharts of FIGS.

The flowchart of FIG. 27 shows a series of bus operations from the occurrence of a bus reset until the node ID is determined and data transfer can be performed.

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 or the like, 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. As step S103,
When the parent-child relationship is determined between all nodes, step S
One route is determined as 104. 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, the ID (p
An operation of setting a node ID for giving a physical ID is performed. The node IDs are set in a predetermined node order, and the setting operation is repeatedly performed until 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 set. Has been recognized at all nodes,
In step S107, data transfer between nodes can be performed, and data transfer is started. In this step, the self-identification packet of FIG. 25 and FIG. 1 is transmitted to the network.

In the state of step S107, a mode for monitoring the occurrence of a bus reset again is entered.
When the bus reset occurs, the setting operation from step S101 to step S106 is repeatedly performed.

The flow chart of FIG. 27 has been described above. The flow chart of FIG. 27 shows the portion 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 flow chart. Are shown in FIGS. 28 and 29, respectively.

First, the flowchart of FIG. 28 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, as a first step of re-recognizing the network connection status reset in step S202, a flag indicating a leaf (node) is set for each device. Further, in step S203, each device checks how many ports it has are connected to other nodes.

According to the result of the number of ports in step S204, the number of undefined (undetermined parent-child) ports is checked in order to start the declaration of the parent-child relationship. Immediately after the bus reset, the number of ports = 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. A leaf can be known by checking the number of ports in step S203. In step S205, the leaf declares "I am a child and the other is a parent" to the node connected thereto, and ends the operation.

A node which has a plurality of ports in step S203 and is recognized as a branch has an undefined port number> 1 in step S204 immediately after the bus reset.
Moving to step S206, a flag of branch is first set, and in step S207, the process waits for acceptance 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 returns to step S20.
Confirm the number of undefined ports of 4 and find that the number of undefined ports is 1
If it becomes, it becomes possible to declare “I am a child” in step S205 for the node connected to the remaining port. After the second time, step S204
Even if the number of undefined ports is confirmed in step S207, 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 allow child declaration) becomes zero as a result of the number of undefined ports in step S204, And the only node for which the number of undefined ports has become zero (all are determined as parent ports) is flagged as a root in step S208,
In step S209, the route is recognized.

Thus, the process from the bus reset shown in FIG. 28 to the declaration of the parent-child relationship between all nodes in the network is completed.

Next, the flowchart of FIG. 29 will be described.

First, in the sequence up to FIG.
Since the information of the flag of each node such as branch and route is set, it is separated based on this information in step S301.

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

In 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 arbitration into one) in step S304, and proceeds to step S3.
As 05, an ID number is given to one winning node, and a failure result is notified to the losing node. In this arbitration, for example, the port with the smallest number is given priority.
In step S306, the leaf whose ID acquisition has failed fails issues an ID request again, and repeats the same operation. I
From step S307, the ID information of the node is broadcast and transferred to all nodes from the leaf from which D has been obtained. The packet shown in FIG. 25 and FIG. 1 is transferred as this ID information. When the broadcasting of the ID information of one node ends, the number of remaining leaves is reduced by one in step S308. Here, step S309
When the number of the remaining leaves is 1 or more, the operation from the ID request in step S303 is repeatedly performed, and finally, when all the leaves broadcast the ID information, N = 0 in step S309, and the next branch. To ID setting.

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

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 as step S312, and gives the branch in order from the winning branch to the next youngest number that has been given to the leaf. In step S313, the root notifies the branch that issued the request of ID information or a failure result, and 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 broadcast and transferred to all the nodes from the branch where the ID has been obtained. When the broadcast of the one node ID information ends, the number of remaining branches is reduced by one in step S316. Here, step S
If the number of the remaining branches is 1 or more as 317, the operation from the ID request in step S311 is repeated.
The process is performed until all the branches finally broadcast the ID information. When all the branches have acquired the node IDs, 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
318 is set as the own ID number among the unassigned numbers, and the root I
Broadcast D information.

Thus, as shown in FIG. 29, the procedure from the determination of the parent-child relationship to the setting of the IDs of all the nodes is completed.

[Second Embodiment] FIG. 22 shows the format of self-identification information added in the second embodiment.
Here, a 64-bit Node_Unique_ID is added to the self-identification information. Node_Unique_I
D is composed of two fields: a high-order 24-bit node_vendor_id field and a low-order 40-bit chip_id field. Each field is a Configurable defined by IEEE1394.
Bus_Info_Block of the relation ROM
Node_vendor_id, chip_id in
Stores the same value as the field. Also, 1 quadl
Since it is not possible to put all Node_Unique_ID information in the “et”, 2b called i field
It is provided with a count bit of "it" and transmitted by dividing into four.

The node_vendor_id field is identification information unique to a company that provides a component, also called CompanyID. This Com
The panyID is IEEE / RAC (Registrat)
ion Authority Committee). The chip_id field is
This is an identification field that can be freely defined by each company. N composed of these two identification fields
The mode_Unique_ID is the only information that can specify the node connected on the bus.

Although the IEEE 1394 bus is automatically assigned a node_ID, it is not guaranteed that if the topology of the bus changes, the node_ID will be the same as the previous state. Thus, after a change in topology, nod
Communication cannot be resumed by identifying the partner node by e_ID.

Therefore, Nod is added to the Self ID packet.
By adding the e_Unique_ID, the node can be completely identified only by the process of establishing the topology of the bus. Therefore, after establishing the bus topology,
By reading the Node_Unique_IDs of all nodes, the communication partner can be re-identified and the process can be omitted.

[Third Embodiment] FIG. 23 shows a format of self-identification information added in the third embodiment. d
device_class and sub_device_cl
Two 8-bit fields called ass are added to the self-identification information. FIG. 24 shows device_class and s
An example of the correspondence of ub_device_class has been shown. device_class indicates a major classification of the node, and sub_device_class indicates device.
This is a small classification of ce_class. For example, de
device_class0x00, sub_device
If _class is 0x00, it indicates that the PC belongs to the large category of computer. Also dev
ice_class0xFF, sub_device_
If class is 0x03, it indicates that the node is a multifunction node that can provide a plurality of functions, and the numerical value of sub_device_class in this case indicates the number of functions.

As described above, the function provided by the node
By dividing into ss and entering the self-identification information, it is possible to roughly specify in advance all nodes on the bus that have the functions required by themselves and obtain detailed information on those nodes This makes it possible to satisfy the demand.

Up to now, Configuration_
ROM_length, max_rec, Node_U
nique_ID, device_class, sub
Embodiments in which information such as _device_class and the like are added to self-identification information have been individually described.
N: E of SelfID packet defined in 394
The value of the xended field (defined from 0 to 2) may be appropriately allocated among 3 to 8, and a format may be used in which all of this information is transmitted simultaneously or selectively.

[0091]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

An object of the present invention is to provide a storage medium storing the program codes of the procedures shown in FIGS. 27 to 29 for realizing the functions of the above-described embodiment to a system or an apparatus, and to provide a computer for the system or apparatus. (Or CPU or MPU) by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

Examples of a storage medium for supplying the program code include a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, and CD.
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) Performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, The case where the CPU of the function expansion board or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing is also included.

[0097]

As described above, by notifying the self-identification information of the data communication device connected on the communication line in the topology establishment process, the communication efficiency can be improved.
It is possible to omit a useless communication process for acquiring self-identification information.

[Brief description of the drawings]

FIG. 1 shows a data capacity and a reception buffer Y in self-identification information.
FIG. 4 is a diagram illustrating a format for adding a size.

FIG. 2 is a diagram illustrating a configuration example of a communication device used in the present invention.

FIG. 3 is a diagram for explaining the correspondence between codes and capacities of a reception buffer;

FIG. 4 is a diagram illustrating a process of establishing a topology.

FIG. 5 is a diagram illustrating a process of establishing a topology.

FIG. 6 is a diagram illustrating a topology establishment process.

FIG. 7 is a diagram illustrating a process of establishing a topology.

FIG. 8 is a diagram illustrating a topology establishment process.

FIG. 9 is a diagram illustrating a process of establishing a topology.

FIG. 10 is a diagram illustrating a process of establishing a topology.

FIG. 11 is a diagram illustrating a process of establishing a topology.

FIG. 12 is a diagram illustrating a process of establishing a topology.

FIG. 13 is a diagram illustrating a process of establishing a topology.

FIG. 14 is a diagram illustrating a process of establishing a topology.

FIG. 15 is a diagram illustrating a process of establishing a topology.

FIG. 16 is a diagram illustrating a process of establishing a topology.

FIG. 17 is a diagram illustrating a process of establishing a topology.

FIG. 18 is a diagram illustrating a topology establishment process.

FIG. 19 is a diagram illustrating a process of establishing a topology.

FIG. 20 is a diagram illustrating a process of establishing a topology.

FIG. 21 is a diagram illustrating a process of establishing a topology.

FIG. 22 is a diagram illustrating a format for adding a unique identification code to self-identification information.

FIG. 23 is a diagram illustrating a format for adding a function classification to self-identification information.

FIG. 24 is a diagram illustrating an example of a function classification code.

FIG. 25 is a diagram illustrating a format of conventional self-identification information.

FIG. 26 is a diagram illustrating a format of conventional self-identification information.

FIG. 27 is a flowchart of a topology establishment process.

FIG. 28 is a flowchart of a topology establishment process.

FIG. 29 is a flowchart of a topology establishment process.

[Explanation of symbols]

 201 Physical layer 202 Link layer 203 Transaction layer 204 Serial bus manager 205 Application layer

Claims (5)

[Claims] 1. A data communication device connected to a network and reconstructing the topology when a change in the topology of the network occurs. The data communication device executes a predetermined procedure with the connected data communication device to Means for reconstructing the self-identification information after the topology restructuring, including at least one of the total capacity of the self-identification information, the receivable data capacity, the unique identification code, and the classification information of the function to be provided. Means for transmitting identification information to a node connected to a network. 2. The network according to claim 1, wherein said network is IEEE 1394.
2. The data communication device according to claim 1, wherein the data communication device is configured by a serial bus. 3. A method for controlling a data communication device connected to a network and reconstructing the topology when a change in the topology of the network occurs, wherein a predetermined procedure is executed between the data communication device and the connected data communication device. Rebuilding the topology by rebuilding, after the topology rebuilding, at least one of the total capacity of the self-identification information, the receivable data capacity, the unique identification code, and the classification information of the provided function. Transmitting self-identification information to the node connected to the network. 4. The network according to claim 1, wherein said network is IEEE 1394.
4. The control method according to claim 3, wherein the control method comprises a serial bus. 5. A means for executing a predetermined procedure between a computer connected to a network and a connected data communication apparatus to reconstruct a topology, and after reconstructing the topology, a total capacity of self-identification information. And a program that functions as means for transmitting self-identification information including at least one of information of receivable data capacity, unique identification code, and classification information of a provided function to a node connected to a network. A computer-readable storage medium for storing.