JP3085398B2 - Device number setting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of communication devices connected by cables, and more particularly to a circuit suitable for forming a device number for distinguishing the plurality of communication devices. .

[Conventional technology]

In the conventional communication device, a plurality of communication devices are connected by a cable, and a transmission device number is added to transmission data so that the transmission source can be distinguished, but the device number is an independent number in a communication system. There is a need. Conventionally, the setting of the device number has been set by a switch. However, the setting by the switch has a problem that the communication operation is not performed normally if an erroneous setting occurs.

[Problems to be solved by the invention]

The above-mentioned prior art does not take into consideration that erroneous setting may be caused by individually performing switch setting. For example, when the switches of two devices have the same setting, there are two devices having the same device number, and there is a problem that normal data communication cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to prevent a switch from being erroneously operated, and an object of the present invention is to provide a device number setting method for realizing a switchless operation.

[Means for solving the problem]

In order to achieve the above object, each communication device is provided with a device number recognition terminal, and further provided with a device number setting terminal in a cable. A part of the device number recognition terminal (first device number recognition terminal) is connected to a power supply via a resistor at the same time as a decoder is provided in the communication device. The second device number recognition terminal is connected to the ground in the communication device.
On the other hand, the device number setting terminal is connected to either a closed circuit or an open circuit by a cable. The closed circuit connects the first device number recognition terminal and the second device number recognition terminal in a cable, and the open circuit connects the first device number recognition terminal to the first device number recognition terminal.
And the second device number recognition terminal are not connected.

[Action]

In a plurality of communication devices connected by cables, when the specific terminal and the ground form a closed circuit, they can be decoded as L input, and when they form an open circuit, they can be decoded as H input. The output of the decoder can be determined by the combination of the closed circuit and the open circuit. This combination can all be different for each communication device. Thereby, a different device number can be given to all communication devices.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a connection diagram for a plurality of communication devices. Each communication device
1, 11 and 21 are connected by a cable 100. In the communication device 11, the input of the decoder 12 is connected to pull-up resistors 14 and 16, and the pull-up resistor 14 side is connected to a ground 17 And the pull-up resistor 16 side is connected to the in-cable open circuit 111, but is not connected to the ground 13, so it becomes an H input. As a result, the decoder 12 receives the L and H signals and outputs a signal 15 representing the device number 1.

On the other hand, the communication device 1 connects the input of the decoder 2 to the pull-up resistors 4 and 6, and the pull-up resistors 4 and 6 are connected to the grounds 3 and 7 of the communication device 1 via the in-cable closed circuits 101 and 102, respectively. Therefore, it becomes L input. As a result, the decoder 2 receives the L signal and outputs a signal 5 representing the device number 0. In this way, by setting the combination of the closed circuit and the open circuit of the cable differently at the connection portion of each communication device, different device numbers can be given to all communication devices.

FIG. 2 shows a configuration of a duplex computer according to another embodiment of the present invention. One computer includes system buses 300 and 310, basic processing units (BPUs 320 and 330), a main memory (MS340 and 350), and a shared memory (CM200 and 210).

Two computers having the above configuration are arranged, and a shared memory of the two computers is connected by a cable 220.

Two of the signal lines of this cable are used for device number setting.

FIG. 3 clearly shows only the device number setting portion of the cable. In the common memory card 200, a signal determination element 202 is connected to a pull-up resistor 203, and a connector
The cable-side specific terminal 221 is connected to the connector-side specific terminal 205 through the cable 204, and the cable-side specific terminal 222 in the cable 220.
The cable-side specific terminal 222 is connected to the connector-side specific terminal 206 and to the ground 207. As a result, the L signal is input to the input of the signal determination element, and the output of the signal determination element outputs L. In one common memory card 210, a signal determining element 212 is connected to a pull-up resistor 217, and is connected to a connector-side specific terminal 215 and a cable-side specific terminal 223 through a connector 214. Note that the cable-side specific terminal 223 is not connected to the ground, and as a result, H
The signal is input, and the output of the signal determination element becomes H.

With the above configuration, the device number of the common memory can be determined only by connecting a cable to the device without setting means such as a switch.

This device number can be used to determine the startup priority at the time of power recovery.

According to this method, even if the cable is inserted reversely, only the device number is changed between the duplex systems, and an error such as the same setting by the switch does not occur.

FIG. 4 clearly shows a device number setting circuit with a connector wrong removal prevention circuit. The input of the inverter 302 is connected to the pull-up resistor 300, and is connected to the ground 301 in its own device via the in-cable closed circuit 305.

When the connector is connected, the signal becomes a signal from the ground 301, so that the L signal is inverted by the inverter 302 through the cable internal closed circuit 305 and becomes H, so that the H signal is input to the OR gate 303. pass. When the connector is pulled out, the H signal from the pull-up resistor 300 is inverted by the inverter 302, so that the OR gate 303
Receives an L signal. Therefore, the signal from the decoder is latched by a through latch.

When the power is turned on, the power-on pulse signal becomes H for a certain period of time and the input data is latched. Therefore, even when the cable is not connected, the through latch output signal 306 does not become unstable.

As described above, even if the connector is unplugged or pulled out by mistake, the device number is retained by the through latch, so that a malfunction due to the device number indefinite for the internal circuit can be prevented.

〔The invention's effect〕

According to the present invention, since the device number can be automatically set by connecting a cable, there is an effect of preventing a setting error operation.

In addition, since the switch can be omitted, the number of parts can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a communication system according to one embodiment of the present invention, FIG. 2 is a block diagram of a redundant computer system according to another embodiment of the present invention, and FIG. FIG. 4 is a circuit diagram showing a device number setting unit, and FIG. 1,11,21 ... Communication device, 2,12,22 ... Decoder, 3,7,13,1
7,24,27 …… Ground, 4,6,14,16,24,26 …… Pull-up resistor, 5,15,24 …… Decoder output, 100 …… Cable, 10
1,102,112 ... closed circuit, 111,121,122 ... open circuit.

Continuing from the front page (72) Inventor Mitsuaki Kobayashi 5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi, Ltd. Omika Plant (72) Inventor Ryuichi Watanabe 5-2-1 Omika-cho, Hitachi City, Ibaraki Hitachi Inside Process Computer Engineering Co., Ltd. (72) Takashi Kitada, Inventor 5-2-1 Omikacho, Hitachi City, Ibaraki Prefecture Inside Hitachi Process Computer Engineering Co., Ltd. (72) Inventor Takehiro Asakura 5, Omikamachi, Hitachi City, Ibaraki Prefecture No. 2-1 Hitachi Process Computer Engineering Co., Ltd. (56) References JP-A-2-22459 (JP, A) JP-A-56-65503 (JP, A) JP-A-2-296430 (JP, A) JP-A-1-138836 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/42

Claims (1)

(57) [Claims] 1. A device number setting device for a communication system in which a plurality of devices are connected by a cable, wherein the device number setting device comprises a set of a terminal connected to a power supply via a resistor and a terminal grounded. A receptacle-side connector having at least one device number recognition terminal comprising at least one set of terminals and a connector disconnection recognition terminal; and a device provided on the cable and corresponding to the device number recognition terminal and connecting the device number recognition terminal. A plug-side connector having a number setting terminal; a decoder for obtaining a device number from a voltage of the device number recognition terminal determined by a connection of the device number setting terminal; and a connector disconnection recognized by the terminal for connector disconnection recognition. Latch means for holding a device number output by the decoder, wherein the device number of each device is Device number setting apparatus characterized in that it is determined by a combination of wire pre-connected the device number setting pin connected plug-side connector of the cable to the Takuru connector.