JPH07219890A - Method for transmitting data - Google Patents

Abstract

PURPOSE:To enable executing transmission at high-speed by outputting a signal to an equipment usage selecting line which is arranged at a parallel bus connecting device itself at the time of selecting the opposite equipment for data transfer. CONSTITUTION:The equipment 8 outputs the recognition number ID=4 of its own station, the recognition number ID=0 of the opposite equipment and the connection number ID=1 of the parallel bus connecting device 1 itself on a parallel bus B to the data bus B2. The parallel bus connecting device 1 inputs a signal outputted to the data bus B2 to an equipment selecting signal converter 13 by way of the equipment usage selecting line 15. The equipment 1 is selected in the parallel bus A through the use of the recognition number of ID=2 and ID=0. ID is also zero in the equipment 5 of the parallel bus B but three ID s are outputted to the parallel bus B and the signal with more than three bits on the data bus comes to be true so that the equipment 5 recongizes that its own station is not selected as the opposite equipment and executes no responce.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission method for connecting two parallel buses by means of a parallel bus connection device and transmitting data between devices connected to the two parallel buses.

[0002]

2. Description of the Related Art SCSI (Small Computer)
The r Systems Interface) bus is a bus in which all devices connected to the bus can be a bus master. Operating environment is ANSI X3.131-19
The SCSI bus established in 86 roughly divides the bus usage state into four phases, a bus free phase, an arbitration phase, a selection / reselection phase, and a transfer phase. In the bus free phase, the data bus is not being used, and in the arbitration phase, each device has a right to use the data bus.

Here, the arbitration phase will be specifically described. When each device is about to use the data bus, the state of the data bus is
After confirming that it is free, the ID assigned to your station
A signal is output onto the data bus corresponding to the number (recognition number) (this is called a device use selection line). Other devices can also be sequentially output within a predetermined time interval. Check all data buses after a predetermined time. The bus use right is given to the device that has determined that the device having higher priority than the own station is not outputting the use signal on the data bus. The device that has acquired the bus usage right proceeds to the next phase. The device that determines that the device having a higher priority than the own station is outputting the use signal on the data bus cancels the use request of the data bus. The above operation procedure is called an arbitration phase, and the device connected to the SCSI bus acquires the bus use right through this procedure.

Conventionally, a SCSI bus having the above-mentioned bus use right decision system is used as a parallel bus, and the parallel buses are connected to each other via a parallel bus connection device, and between devices connected to two different parallel buses. There is a data transmission device that is capable of transmitting data. In this data transmission device, the parallel bus is provided with a device use selection line corresponding to each device in a ratio of 1: 1. In such a data transmission device, a device having a bus use right outputs a signal to both the device use select line of its own station and the device use select line of the partner device that exchanges information on the parallel bus. This selects the other device.

However, when a partner device on the other parallel bus is selected from the parallel bus on the side which has acquired the bus use right, the parallel bus connecting device is selected once on the side which has acquired the bus use right, Again, the other parallel bus must acquire the bus usage right and select the partner device, and the device must be selected twice. Therefore, it takes a long time to select a device via the parallel bus connection device. If the selection of the partner device is limited to only the parallel bus side that has acquired the bus use right in order to speed up the device selection, there is a problem that the number of selected partner devices decreases. In addition, the identification numbers can be duplicated between different parallel buses. Therefore, for example, there is a device with ID = 1 on a certain parallel bus,
If there is a device with ID = 1 on another parallel bus, and the device that has acquired the bus usage right selects the device with ID = 1 as the partner device, the partner device is on which parallel bus I
There is a problem that it is difficult to distinguish whether the device is D = 1.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and the device selection between two parallel buses connected to a parallel bus connecting device is selected from the conventional two times. By reducing the number of times, the transmission speed is increased, the devices on the parallel bus connected to the parallel bus connection device can be effectively used, and even if the identification numbers are duplicated among the devices on different parallel buses It is an object of the present invention to realize a data transmission method capable of distinguishing a partner device.

[0007]

The present invention is a data transmission method as follows. (1) A parallel bus to which a plurality of devices are connected is drawn, and a device use selection line corresponding to each device is provided on the parallel bus, and two parallel buses are connected via a parallel bus connection device. Is a data transmission method for transmitting data between devices connected to two parallel buses, the device having acquired the bus usage right of the parallel bus when selecting a partner device for data transfer. , If there is a partner device on the parallel bus to which the own station is connected, output a signal to the device usage selection line of the own station and the device usage selection line of the partner device, select the device, and connect If there is no other device on the parallel bus, the signal is output to the device use selection line of the local station, the device use selection line corresponding to the partner device, and the device use selection line assigned to the parallel bus connection device itself. Select the device to obtain the bus usage right. Equipment checks the signal of the device used selection line, if the signal to the device using selection line one station other than the apparatus used selection line and the local station of the self station is output,
If the local station judges that it has been selected as the partner device and responds to the selection, and if signals are output to the device usage selection lines of three or more stations, then it judges that the local station has not been selected as the partner device. And a data transmission method characterized by not responding to the selection. (2) An identification number is assigned to each device connected to the parallel bus, and the identification numbers can be duplicated between different parallel buses, and the device is output according to the identification number output to the parallel bus. When a signal is output to the usage selection line and data is transmitted between devices connected to two different parallel buses, the device that has acquired the bus usage right is connected to one of the parallel buses to which its own station is connected. On the other hand, the identification number of the own station, the identification number of the partner device, and the identification number assigned to the parallel bus connection device itself in the one parallel bus are output,
The parallel bus connection device outputs the identification number of the partner device and the identification number assigned to the parallel bus connection device itself on the other parallel bus to the other parallel bus (1). Described data transmission method.

[0008]

According to the present invention as described above, when the device that has acquired the bus use right of the parallel bus selects the partner device for data transfer, if the partner device is on the parallel bus to which the own station is connected. Outputs a signal to the device use selection line of its own station and the device use selection line of the partner device to select the device. If there is no partner device on the parallel bus to which the own station is connected, the device usage selection line of the own station and the device usage selection line corresponding to the partner device, and the device usage assigned to the parallel bus connection device itself. A signal is output to the select line to select the device. For devices that do not acquire the right to use the bus, check the signal on the device use select line, and if a signal is output to the device use select line of your own station and the device use select line of one station other than your own station, It judges that its own station is selected as the partner device and responds to the selection. If signals are output to the device use selection lines of three or more stations, it is determined that the own station has not been selected as the partner device and does not respond to the selection. An identification number is assigned to each device connected to the parallel bus, and the identification number can be duplicated between different parallel buses. A signal is output to the device use selection line according to the identification number output to the parallel bus. When transmitting data between devices that are connected to two different parallel buses, the device that has acquired the bus usage right will use the identification number of its own station for one of the parallel buses to which its own station is connected. , The identification number of the partner device and the identification number assigned to the parallel bus connection device itself on one of the parallel buses are output. The parallel bus connection device, for the other parallel bus, the identification number of the other device,
The identification number assigned to the parallel bus connecting device itself on the other parallel bus is output.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. Figure 1
FIG. 1 is a configuration diagram showing a configuration example of a data transmission device used for implementing the present invention. In FIG. 1, A and B are parallel buses, 1 is a parallel bus connecting device for connecting the parallel buses A and B, and C1 to C4.
And D1 to D4 are devices connected to the parallel buses A and B, respectively. The parallel bus A includes a data bus A1 and a control bus A2, and the parallel bus B includes a data bus B1 and a control bus B2. The parallel buses A and B are buses that select devices according to the same procedure. In other words, these parallel buses consist of a bit on the data bus corresponding to the own station and a bit on the data bus corresponding to the partner device to be selected when the device that has acquired the bus use right selects the partner device. It is a parallel bus that is selected by making both true. Here, the data bus of the parallel bus is provided with a device use selection line corresponding to each device connected to the parallel bus in a 1: 1 relationship. Each device use selection line corresponds to each bit on the data bus.

The devices connected to the parallel buses A and B are
Selection is possible depending on the device that has acquired the bus usage right when it has not acquired the bus usage right. The procedure will be described. FIG. 2 is a flowchart showing a procedure for selecting a device that has not acquired the bus use right. As shown in Fig. 2, the device that has not acquired the bus usage right checks each bit on the data bus where the signal is output by the device that has acquired the bus usage right, If only 1 bit is true, it recognizes that its own station is selected as the partner device and responds to the selection. If the signal of 3 bits or more on the data bus is true, it recognizes that its own station has not been selected as the partner device and does not respond to the selection.

FIG. 3 is a flowchart showing a procedure in which a device that has acquired the bus use right selects a partner device for data transfer. As shown in FIG. 3, a device that has acquired the bus use right has a bit corresponding to its own station and a bit corresponding to the other device on the data bus when the other device is on the parallel bus to which the own station is connected. And true at the same time. If there is no other device on the parallel bus to which the own station is connected, the bit corresponding to the own station on the data bus and the bit corresponding to the parallel bus connection device in addition to the bit corresponding to the other device are true. To

Returning to FIG. 1, the specific configuration of the parallel bus connection device 1 will be described. In FIG. 1, the parallel bus A is connected to devices 1 to 4 with identification numbers ID = 0, 1, 3, and 4, respectively. Similarly, the parallel bus B is also connected to the devices 5 to 8 with the identification numbers ID = 0, 2, 3, and 4, respectively. Further, in the parallel bus connection device 1, the identification number ID = 2 is attached to the parallel bus A, and the identification number ID = 1 is attached to the parallel bus B.
Note that FIG. 1 shows an example, and the number of connected devices and the identification number may be other than this.

In the parallel bus connection device 1, a bus right transfer control unit 11 is connected to the parallel buses A and B. This control unit acquires the bus use right of both buses at the same time based on the acquisition procedure of the bus use right of the parallel buses A and B, outputs the ID of the device that has acquired the bus use right by the signal a, and outputs the signal b. Outputs a write signal of the identification number. Reference numeral 12 denotes a bus usage right acquisition / storage unit, which writes the identification number output from the bus usage right transmission control unit 11 into a write signal b.
Then, the identification number is output according to the signal requested by the signal c. Reference numeral 13 is a device selection signal converter, one of which is connected to the parallel bus A and the other of which is connected to the parallel bus B. This converter knows the identification number for which the bus use right is acquired by the signal d (the identification number read from the bus use right acquisition storage unit 12), and the identification numbers on the parallel bus A side and the parallel bus B are determined by the signals e and f. Knowing the identification number of each side, it outputs the identification number of each bus of the parallel bus connection device. The signal g is a start signal for the device selection signal converter 13. The device that has acquired the bus use right has the bit on the data bus corresponding to the identification number of its own station, the bit on the data bus assigned to the parallel bus connection device on the parallel bus where the own station is, and the device of the other device. Output the identification number. In response to this, the device selection signal converter 13 knows the identification number of the device that has acquired the bus right from the signal d, and the identification number of the partner device and the identification number of the parallel bus connection device itself on the opposite side parallel bus. To the parallel bus on the other side. Reference numerals 14 and 15 are equipment use selection lines that form a data bus, and connect the equipment selection signal converter 13 to the parallel bus A and the parallel bus B. The device use selection lines 14 and 15 are composed of a device use selection line corresponding to each device connected to the parallel bus, and a device use selection line of the parallel bus itself. In FIG. 1, four devices are connected to each of the parallel bus A and the parallel bus B, and the parallel bus connection device itself has the identification number for the parallel bus A and the identification number for the parallel bus B. 14 and 15 are 0
Five to four are provided. The signal of one device use selection line corresponds to a 1-bit signal on the data bus. Reference numerals 16 and 17 are ID setting units in which the identification numbers of the parallel bus connection devices 1 themselves in the parallel buses A and B are set. 18 is a parallel bus connection control unit,
When the signal provided from the control bus of the parallel bus indicates that the procedure for selecting the partner device has started, the signal g is output.

The operation of the thus configured data transmission device will be described. A case where the device 8 connected to the parallel bus B selects the device 1 as the partner device will be described as an example. The ID setting unit 16 for the parallel bus A is set to ID = 2, and the ID setting unit 17 for the parallel bus B is set to ID = 1. The device 8 connected to the parallel bus B acquires the bus use right of the parallel bus B, and simultaneously acquires the use right of the parallel bus A by the bus use right transmission control unit 11. At this time, the bus right-of-use transmission control unit 11 sends the signal a
ID = 4 is output to and is stored in the bus usage right acquisition storage unit 12. When the device 8 starts the procedure of selecting the partner device, the parallel bus connection control unit 18 outputs the signal c and the signal g, causes the bus usage right acquisition storage unit 12 to output ID = 4 through the signal d, and outputs the device selection signal. Notify the converter 13 that the selection procedure has started. Since the device 8 uses the device 1 as the partner device, its own station identification number ID = 4, the partner device identification number ID = 0, and the identification number ID = 1 of the parallel bus connection device 1 itself on the parallel bus B. Is output to the data bus B2. The parallel bus connection device 1 inputs the signal output to the data bus B2 to the device selection signal converter 13 via the device use selection line 15. The device selection signal converter 13 is
Make sure that ID = 4 given by signal d and ID = 1 given by signal f are on the data bus B2. Since ID = 1 is the identification number given to the parallel bus connection device 1 itself on the parallel bus B, it is not output to the parallel bus A. ID = 4 is the device 8 that has acquired the bus usage right
Device identification signal converter 13 converts this to the identification number ID = 2 of the parallel bus connection device 1 itself on the parallel bus A, and the identification number ID = 0 of the partner device is added to the parallel bus A. Output to. I on parallel bus A
The device 1 is selected using the identification number of D = 2 and ID = 0. Here, the device 5 on the parallel bus B also has ID = 0, but since three IDs are output on the parallel bus B and the signal of 3 bits or more on the data bus is true, the device 5 Recognizes that its own station was not selected as the partner device and does not respond. In this way, IDs for both parallel buses A and B
Even if there is a device of = 0, it is possible to distinguish and select the other device.

When the device 8 selects the device 2 as the partner device, the identification number ID = 1 of the device 2 and the identification number ID = 1 of the parallel bus connecting device 1 on the parallel bus B overlap. In this case, the device 8 outputs ID = 4 and ID = 1 on the data bus B2. The parallel bus connection device 1 recognizes that only two IDs are output on the data bus B2, converts ID = 4 to ID = 2, outputs the ID to the parallel bus A, and outputs another ID. ID = 1 is output to the parallel bus A as it is.

[0016]

According to the present invention, the following effects can be obtained. When a device that has acquired the bus usage right for the parallel bus selects the partner device for data transfer, if there is no partner device on the parallel bus to which the own station is connected, In addition to the device use select line of the partner device, the signal is output to the device use select line assigned to the parallel bus connection device itself. As a result, the device selection between the two parallel buses connected to the parallel bus connection device is reduced from the conventional two times to one time, so that the transmission speed can be increased. Also,
Devices on the parallel bus connected to the parallel bus connection device can be effectively used. The parallel bus connection device itself has an identification number on the parallel bus, and the identification number of the device that has acquired the bus usage right is converted into the identification number of the parallel bus connection device itself, and the device is connected to two different parallel buses. Data is being transmitted between. As a result, even if the identification numbers are duplicated between the devices on the two parallel buses, the counterpart device can be distinguished.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure for selecting a device that has not acquired a bus use right.

FIG. 3 is a flowchart showing a procedure in which a device that has acquired the bus use right selects a partner device for data transfer.

[Explanation of symbols]

 A, B Parallel buses C1 to C4, D1 to D4 Devices 1 Parallel bus connection device 11 Bus usage right transmission control unit 12 Bus usage right acquisition storage unit 13 Device selection signal converter 14, 15 Device usage selection line 16, 17 ID setting Part 18 Parallel bus connection control unit

Claims (2)

[Claims] 1. A parallel bus to which a plurality of devices are connected is drawn, and a device use selection line corresponding to each device 1: 1 is provided on the parallel bus, and two parallel buses are provided through a parallel bus connection device. A data transmission method for connecting buses to each other and transmitting data between devices connected to two parallel buses, wherein a device that has acquired the bus usage right of the parallel bus selects a partner device for data transfer. If there is a partner device on the parallel bus to which your station is connected, select a device by outputting a signal to the device usage selection line of your station and the device usage selection line of your partner device If there is no partner device on the parallel bus connected to, the signal is sent to the device usage select line of the local station, the device usage selection line corresponding to the partner device, and the device usage selection line assigned to the parallel bus connection device itself. Output, select the device, and For the equipment that does not obtain, check the signal on the equipment use selection line, and if the signal is output to the equipment use selection line of the own station and the equipment use selection line of one station other than the own station, the own station is the partner. If it is judged that it has been selected as a device and responds to the selection, and if a signal is output to the device usage selection lines of three or more stations, it is judged that the local station was not selected as the partner device and selected. A data transmission method characterized by not responding to the request. 2. An identification number is assigned to each device connected to the parallel bus, and the identification number can be duplicated between different parallel buses, and the identification number output to the parallel bus is allowed. When a signal is output to the device use selection line and data is transmitted between the devices connected to two different parallel buses, the device that has acquired the bus use right is the one connected to the local station. The identification number of the local station, the identification number of the partner device, and the identification number assigned to the parallel bus connection device itself on the one parallel bus are output to the bus, and the parallel bus connection device 2. The data transmission method according to claim 1, wherein the identification number of the partner device and the identification number assigned to the parallel bus connecting device itself in the other parallel bus are output to the bus.