JPH11252147A - Serial bus system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the serial bus system by which a plurality of data are transferred in parallel simultaneously. SOLUTION: In the serial bus system, each device is connected by using a serial bus to establish a tree structure in the case of using each device as each node 20, and data are transferred among the nodes on the outside of a prescribed path in parallel with data transfer through a path between the prescribed nodes 20 by providing a bus arbitration function in each node.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial bus system in which a personal computer (PC) or the like as a node is connected to a peripheral device such as a disk or printer as a node by a connection cable, and more particularly to a plurality of data transfers. And a serial bus system capable of executing the processes in parallel.

[0002]

2. Description of the Related Art Generally, a personal computer as a node (P
There is a serial bus method as a bus method for connecting a peripheral device such as a disk or a printer as a node with a connection cable. This is a personal computer (PC),
The peripheral devices are connected by using a serial bus, and an example is as shown in FIG. That is, as shown in FIG. 5, the serial bus configuration includes a personal computer (PC) 1, a monitor display 3, a printer 5,
And a video disk 9 and a VTR 11 are connected to the monitor display 3. A CD-ROM 17 is connected to the video disk 9.
However, a camera 19 is connected to the VTR 11. A scanner 13 is connected to the printer 5, and a magnetic tape device 15 is connected to the hard disk 7. FIG. 6 shows the serial bus configuration shown in FIG. 5 in an abstract tree structure. Here, the nodes # 0 to # 9 shown in FIG. 6 correspond to the PC1 to the camera 19 shown in FIG. Then, in the tree structure of FIG.
Are arranged in the lower hierarchy.

[0003]

In the serial bus system as described above, conventionally, when data is transferred from a certain node (equipment) to a certain node (equipment), the data is arranged outside the path during the data transfer. Data cannot be transferred from node to node despite the fact that
There is a disadvantage that data transfer efficiency is low. The above-mentioned conventional disadvantages will be described in detail with examples. In a serial bus configuration having a tree structure as shown in FIG.
An example in which data cannot be transferred from another node to another node when data is to be transferred from node 13 to node # 16 will be described. Here, “0” is called a node, which represents a device that performs data transfer, and a node (# 0) at the root of the tree is called a root node. In the conventional serial bus system, bus arbitration is performed at the root node (# 0). First, node # 13
In order to transfer data from the node # 16 to the node # 16, as shown in FIG. 8, the node # 13 requests the root node # 0 for a bus use right. The root node # 0 permits the node # 13 to use the bus, and the node # 13 starts data transfer to the node # 16. That is, as shown in FIG. 9, each node in the middle of the bus relays the data packet, and
Is transmitted to all nodes. Then, each node reads the destination node number in the data packet header and captures the packet when addressed to itself (in this case, node # 16 captures the packet). Then node #
13 notifies the root node # 0 of the transfer end. As described above, during the data transfer, that is, when the data transfer is started from the node # 13 to the node # 16, as shown in FIG.
Since the data from node # 13 is transmitted to all nodes and the data packet passes through all nodes, it is impossible to transfer data from another node to another node at that time. . That is, in this conventional configuration, the bus use efficiency is poor. Further, there is a disadvantage that the load on the root node is heavy. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a serial bus system capable of executing a plurality of data transfers simultaneously and in parallel.

[0004]

In order to achieve the above object, the present invention relates to a serial bus system having a tree structure in which each device is connected to each other by using a serial bus so that each device is a node. By providing each node with a bus arbitration function, data transfer between nodes outside the predetermined path is performed in parallel with data transfer on a path between predetermined nodes. Another feature of the present invention is that the device of each of the nodes has storage means for storing the label number of each of the nodes.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on illustrated embodiments. FIG. 1 is a configuration diagram of an embodiment of a serial bus system according to the present invention. In FIG. 1, this serial bus system uses a bus arbitration function when each device (PC and its peripheral device) 20 is connected using a serial bus and each device is a node. In this case, a label provided to each node (described later) is stored in a ROM provided at each node (each device). FIG. 2 is a tree structure diagram of the serial bus system device shown in FIG. 1. Here, label numbers (# 0 to # 21) are assigned to respective nodes in a hierarchical order. Next, the operation of the serial bus configuration as shown in FIGS. 1 and 2 will be described. In FIG.
When data is transferred from node # 13 to node # 16,
First, the node # 13 requests the right to use the bus for data transfer to the node # 16 from the node # 9 (the other node). Then, the node # 9 notifies the node # 14 (nearest and lower layer node) of the bus use right request (hereinafter referred to as a request) by the bus arbitration function. Subsequently, the node # 14 notifies the node # 18 of the request by the bus arbitration function. Node # 18 notifies node # 14 that it is not connected to node # 16. Node # 1
4 notifies the request to the node # 19. The node # 19 notifies the nodes # 20 and # 21 of the request. node#
20, the node # 21 notifies the node # 19 that it is not connected to the node # 16. Accordingly, the node # 14 notifies the node # 9 that it is not connected to the node # 16. Next, node # 9 notifies node # 5 of the request. Node # 5 is node # 10
Notify the request to. Node # 10 notifies node # 5 that it is connected to node # 16. Node # 5 permits node # 13 to use the bus via node # 9. Node # 5 notifies node # 2 that the bus is in use. The nodes # 9 and # 10 notify the nodes # 14 and # 15 that the bus is in use. Node # 13 starts data transfer to node # 16 (see FIG. 3). Each node in the middle of the bus relays data packets. Node # 16 captures the data packet. Node # 13 notifies the end of transfer.

As described above, the operations of searching for a node and transferring data are performed. In the present invention, the data transfer from the node # 13 to the node # 16 is performed as shown in FIG.
, Node # 13 → node # 9 → node # 5 →
Since the data is transmitted only from the node # 10 to the node # 16, and data is not transmitted from the node # 13 to all the nodes as in the conventional example shown in FIG. In parallel with the data transfer from the node # 13 to the node # 16, other data transfer (node # 3 → node # 8 and node # 0 → node # 12) outside the above route becomes possible.

For example, from the node # 13 to the node # 1
And from node # 3 to node # 8 in parallel with the data transfer to node # 6.
When transferring data to the node # 3, the node # 3 requests the right to use the bus for data transfer to the node # 8 to the node # 1, the node # 1 notifies the node # 4 of the request, and the node # 4 transmits the request to the node # 4. Node # 1 notifies that the bus is in use, and node # 4 notifies node # 7 that the bus is in use, and node # 1 notifies node # 0 that the bus is in use. In response, node # 3 starts data transfer to node # 8 (see FIG. 4). When data is transferred from node # 0 to node # 12 in parallel with data transfer from node # 13 to node # 16, node # 0 is
Requesting the right to use the bus for data transfer to the node # 2, the node # 2 notifies the node # 6 of the request, and the node # 6 informs the node # 2 that the node # 6 is connected to the node # 12.
, The node # 6 notifies the nodes # 11 and # 17 that the bus is in use, the node # 2 notifies the node # 5 that the bus is in use, and the node # 0 The data transfer to # 12 is started (see FIG. 4).

[0008]

As described above, according to the present invention, in the serial bus system, each node is provided with a bus arbitration function so that data transfer on a path between predetermined nodes can be performed in parallel with the predetermined path. Since data transfer between external nodes is performed, the efficiency of data transfer is significantly improved.

[Brief description of the drawings]

FIG. 1 is a structural diagram of an embodiment of a serial bus system device according to the present invention.

FIG. 2 is a tree structure diagram of the serial bus type device shown in FIG.

FIG. 3 is an operation explanatory diagram of the serial bus type device shown in FIGS. 1 and 2;

FIG. 4 is an operation explanatory diagram of the serial bus type device shown in FIGS. 1 and 2;

FIG. 5 is a connection diagram showing an example of a serial bus system.

6 is a tree structure diagram of the device shown in FIG.

FIG. 7 is a tree structure diagram of a conventional serial bus system device.

8 is an operation explanatory diagram of the serial bus system shown in FIG. 7;

FIG. 9 is an operation explanatory diagram of the serial bus system shown in FIG. 7;

[Explanation of symbols]

1. Personal computer (PC) 3. Monitor display 5. Printer
7 ... Hard disk, 9 ... Video disk,
11 VTR, 13 Scanner,
15 ... magnetic tape unit, 17 ... CD
-ROM, 19 ... Camera, 20 ...
Each node,

Claims (2)

[Claims] 1. A serial bus system in which each device is connected by using a serial bus to take a tree structure when each device is made to be a node, wherein each node has a bus arbitration function. A serial bus system wherein data transfer between nodes outside the predetermined path is performed in parallel with data transfer on a path between predetermined nodes. 2. The serial bus system according to claim 1, wherein the equipment at each of the nodes has storage means for storing a label number of each of the nodes.