JPH02159849A - Termination resistor connector - Google Patents

Abstract

PURPOSE:To attain the connection of a termination resistor circuit in an optimum state in response to an external input output device by providing a switching drive means whose power is supplied through a signal line and an earth line automatically when the external input output device is connected. CONSTITUTION:When an external input output device 23 is connected to a computer main body 21, a closed circuit is formed in a route of power supply Vd - switch drive source 27 - signal line 24 - earth line G and the drive source 27 is operated. then changeover connection means 27a-27c are thrown to the position A as shown in figure, the device 23 is connected to the main body 21 via an external bus 22 and the termination resistor circuit 28 is connected to the bus 22 to protect the entire operation of the bus. When the device 23 is disconnected from the main body 21 or the bus 22 is disconnected, since the power circuit of the drive source 27 is interrupted, the means 27a-27c are thrown to the position B, resulting that the internal bus 25 of the main body 21 is protected by the termination resistance circuit 26 and the operation of the bus 25 is surely protected.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a terminating resistor connecting device used in a computer system in which a computer main body and an external input/output device are connected to a bus via a terminating resistor. Regarding improvements.

(Prior Art) In general, in this type of computer system, as shown in FIG. A device to which external input/output devices such as a tape device 5 and a floppy disk device 6 are connected, or as shown in FIG. Dissection device 6
etc. are incorporated together to form a computer main body 1, and external input/output devices such as an external auxiliary storage unit 8 are connected to this computer main body 1 via an external bus 2.

9 is an internal bus.

In the computer system described above, for example, in the latter case, the storage device groups 3, 5, 6, etc. are already built into the computer main body 1, so the external auxiliary storage unit 8 is treated as an option. In this case, the external auxiliary storage unit 8 will be attached to or removed from the computer main body 1 as necessary.

Note that this type of connection method is found not only in the one shown in Figure 3 but also in many systems, and one of the representative ones is SCS I (Small Compute
r System Interface) bus is raised.

In such a bus 2, a terminating resistor is provided at the end of the path line, that is, at the input end of the external input/output device. When removed, the terminating resistor is disconnected from the bus 2 and the terminating resistor built into the computer body 1 is connected to the internal bus 9 of the computer body 1, thereby maintaining the electrical characteristics of the entire system.

Conventionally, based on this idea, structures as shown in FIGS. 4 and 'M5 have been realized. FIG. 4 shows a computer main body 1 and an external input/output device connected by an external bus 2 consisting of one signal line, and a changeover switch 11 and a terminating resistor circuit 12a are provided at the output end of the computer main body 1. A terminating resistor circuit 12b is provided at the input end of the external input/output device, for example, the external auxiliary storage unit 8, and when the external input/output device is installed, the changeover switch 11 is set to A.
side and connect the terminating resistor circuit 12b to the end of the external bus 2.
conversely, when it is connected and removed, it is set to the B side and the terminating resistor circuit 12a is connected to the output end of the computer main body 1 to ensure consistency in electrical characteristics.

On the other hand, in FIG. 5, an external input/output device is connected to the computer main body 1 via an external bus 2 consisting of a plurality of signal lines, and in this case, a relay is connected between the power supply Vb and the ground G. 13 and a switch are serially connected, and when connecting an external input/output device to the computer main body L, the switch is turned on to operate the relay 13, and the relay 1
By setting the contacts 13a, 13b, and 13c of 3 to the A side, the computer main body 1 and the external input/output device are connected, and when the external input/output device is removed, the relay 13 is disabled by turning off the switch. The contact 13a of the relay 13 is activated.

Set 13b and 13c on the B side and install the Funpyuta main body 1.
The terminal resistor circuit 12a is connected to the internal bus 9 of the standard &

(Problem to be Solved by the Invention) However, in the above-described terminating resistor connection device, each switch 11. Since this method is used to operate the terminal, there is a problem that the switching timing is incorrect or the switching is forgotten.Also, even if the terminal resistor switching is set correctly, the external bus 2 from the computer main unit 1 or external input/output device is connected to the connector. There is a possibility that the terminating resistor circuit 12b is disconnected from the external bus 2 due to the disconnection in some parts, and troubles may occur throughout the entire bus.

The present invention has been made in view of the above circumstances, and it is possible to automatically connect a terminating resistor circuit according to the external input/output device to the computer main body without any manual intervention, and for example, to prevent disconnection of an external bus. Another object of the present invention is to provide a terminating resistor connecting device that can reliably protect an internal bus.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the terminating resistor connection device according to the present invention connects the external input/output device between the computer main body and the external input/output device in addition to the external bus. A switching drive having a signal line that can be connected and disconnected in conjunction with the connection and separation of the output device, and a switching drive that has individual power supplies at each end of the signal line that is led into the computer main body and the external input/output device. a switching drive means, the switching drive means being provided with a power source and a ground line, the power supply automatically energizing the switching drive source through the signal line and the ground line when an external input/output device is connected to the computer main body; and the switching drive source. switching connection means for connecting an internal bus of the computer main body to the external bus when the switching source is energized, and connecting the internal bus to the first terminating resistor circuit when the switching source is not energized; It is prepared.

(Function) Therefore, by taking the above measures, the present invention forms a closed circuit consisting of a power supply, a switching drive source, a signal line, and a ground line when an external input/output device is connected to the computer main body. This causes the switching drive source to operate. By the operation of this switching drive source, the switching connection means connected to the internal bus of the computer main body automatically selects the external bus and connects the computer main body and the external input/output device. On the other hand, when the external input/output device is disconnected from the computer main body or the external bus is disconnected, the power to the switching drive source is cut off. Since an internal terminating resistor circuit is selected, the terminating resistor circuit can be reliably connected to an external bus or an internal bus.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG. In the figure, 21 is a computer main body,
An external input/output device 23 such as an external auxiliary storage device is detachably connected to the computer main body 21 via an external bus 22. Furthermore, apart from the external bus 22, a single signal line 24 is connected between the computer main body 21 and the external input/output device 23, which connects and separates in conjunction with the approaching and separating operations of the external input/output device 23.

The computer main body 21 has an internal bus 25, a terminating resistor circuit 26, and a switching drive source 27 such as a relay. One end of the switching drive source 27 is connected to a power supply Vd, and the other end is connected to a signal line. It is connected to one end of 24 in a detachable manner. Further, a switching drive source 27 is provided at the end of the internal bus 25.
depending on the operation of the external bus 22 side or the terminating resistor circuit 26
Switching connection means 27a to 27c are provided for selectively connecting the sides. Note that the switching drive source 27 does not necessarily have to be a relay; for example, the presence or absence of an energized state is determined by software, and the internal bus 25 is electrically connected to the external bus 22 or the terminating resistor circuit 26 based on the determination result. It is fine as long as it is done.

On the other hand, the external input/output device 23 has a terminating resistor circuit 28. . . , and a ground line G is connected to the other end of the signal line 24 in a detachable manner.

Next, the operation of the apparatus configured as above will be explained.

First, when the external input/output device 23 is connected to the computer main body 21, a closed circuit consisting of the power supply Vd, the switching drive source 27, the signal line 24, and the ground line G is formed.
The switching drive [27 is activated by d. Therefore, the operation of the switching drive source 27 causes the switching connection means 27a to 27c to
is set on the A side as shown in the figure, and the computer main body 2
1 is connected to an external input/output device 23 via an external bus 22, and terminating resistor circuits 28, . . . are connected to the external bus 22 to protect the operation of the entire bus.

Next, when the external input/output device 23 is disconnected from the computer main body 21 or the external bus 22 is disconnected, the energizing circuit of the switching drive source 27 is disconnected, so the switching connection means 27
a to 27c are set to the B side, and as a result, the internal bus 25 of the computer main body 21 is terminated with the terminating resistor circuit 26, and the operation of the internal bus 25 can be reliably protected.

Therefore, according to the configuration of the embodiment described above, the external bus 22 is connected between the computer main body 21 and the external input/output device 23.
Separately, one signal line 24 is connected, and one end of the signal line 24 is connected to a switching drive source 27, and the other end is connected to the ground line G, so that when the external input/output device 23 is connected to the computer main body 21, automatic The switching drive source 27 operates through the signal line 24 and the ground line G to connect the switching connection means 2.
7a to 27c select the external bus 22, and conversely, when the external input/output device 23 is disconnected or the external bus 22 is disconnected, the switching drive source 27 is de-energized and the internal bus 25 is connected to the internal terminating resistor circuit 26. Since it is connected to the side, the termination resistor circuits 28 and 26 can be automatically connected in an appropriate state with respect to the connection and disconnection of the external input/output device 23, eliminating human connection mistakes as in the past, and The internal bus 25 can be reliably protected even when the bus 22 is disconnected.

[Effects of the Invention] As detailed above, according to the present invention, the termination resistor circuit can be connected automatically and in an optimal state without any human intervention according to the external input/output device to the computer main body. I can do it,
For example, we can provide a terminating resistor connection device that can reliably protect the internal bus even if the external bus is disconnected.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the device of the present invention, Figs. 2 and 3 are block diagrams of a general computer system, and Figs. 4 and 5 are respectively of a conventional terminating resistor connection device. FIG. 21... Computer body, 22... External bus, 2
3... External input/output device, 24... Signal line, 25
... Internal bus, 26.28 ... Termination resistor circuit, 27
...Switching drive source, 27a-27c...Switching connection means, G...Grounding line. Applicant's agent Patent attorney Takeshi Suzue, Hiko

Claims (1)

[Claims] A computer system in which an external input/output device having a second terminating resistor circuit on the input end side is connected to a computer main body having a first terminating resistor circuit so as to be connectable and detachable via an external bus. In addition to the external bus, a signal line is provided between the computer main body and the external input/output device so as to be connectable/separable according to the connection/disconnection of the external input/output device, and a signal line between the computer main body and the external input/output device A switching drive source and a ground line each having an individual power supply are provided at each end of the signal line drawn into the device, and when an external input/output device is connected to the computer main body, the power supply automatically switches the signal line to switching drive means for energizing the switching drive source through the line and the ground line; connecting an internal bus on the computer main body side to the external bus side when the switching drive source is energized;
A terminating resistor connecting device further comprising: switching connection means for connecting the internal bus to the first terminating resistor circuit when the switching drive source is not energized.