JPH0750461B2 - Bus switching method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a system in which a plurality of processing devices are connected by a plurality of buses, and a bus switching signal and a switching completion signal are transmitted and received to switch the bus. The present invention relates to a bus switching method for implementing.

2. Description of the Related Art FIG. 3 shows an example of the configuration of a system including a bus switching control device for performing this type of bus switching and a plurality of processing devices. 10 is a bus switching control device, 20 is a bus, 30 is a processing device, Reference numeral 11 is a reception buffer for receiving the bus switching completion signal. In the conventional case, the bus switching control device 10 sends a bus switching signal to a plurality of processing devices 30 all at once to instruct switching of the bus,
After the bus is switched on the processing device 30 side, the bus switching is performed by returning a bus switching completion signal to the bus switching control device 10. In such a conventional method,
When the bus switching signal is sent, the bus switching completion signals may be sent from the plurality of processing devices 30 all at once, and the reception buffer 11 of the bus switching control device 10 may not be able to receive all the bus switching completion signals. For this reason, there is a drawback that the amount of hardware must be increased because the receiving buffer must be provided on many sides. Alternatively, in order to compensate for this drawback, a method of retransmitting the bus switching completion signal in the processing device 30 or a method of retransmitting the bus switching signal in the bus switching control device 10 is considered, but both of them have the drawback that the processing becomes complicated. was there.

(3) Object of the present invention In a bus switching system in which a bus switching signal is sent all at once and bus switching is confirmed by a bus switching completion signal, the bus switching is performed quickly and the bus switching completion signal is concentrated. It is to provide a bus switching means which is prevented.

(4) Configuration of the Invention (4-1) Differences between Features of the Invention and Conventional Techniques In the present invention, after the bus switching signal is received and the bus switching is performed in the processing device, the bus switching completion signal It uses a bus switching method that delays transmission.
The first embodiment is provided with means for storing the delay information in advance for each processing device, and the second embodiment is one of the modes for preparing the delay information for each processing device, which is address information determined for each processing device. Is used as delay information.

In the conventional bus switching method, there is no means for delaying and sending the bus switching completion signal, and the bus switching completion signal is sent as soon as the bus switching is completed, so the bus switching completion signal can be concentrated on the bus switching control device. However, the present invention differs in that the bus switching completion signal is not concentrated because the bus switching completion signal is delayed and transmitted based on the delay information that differs for each processing device.

(4-2) Embodiment FIG. 1 shows a configuration example for explaining the first embodiment (configuration corresponding to claim (1)) of the present invention, in which the bus is 2 shows an example of a configuration in which two buses are used, one of them is used as an active and the other one is used as a spare, and a bus switching signal is transferred using the same bus as a normal signal. In FIG. 1, a plurality of processing devices 30 and the bus switching control device 10 are connected by a bus 20. Reference numeral 31 is a bus switching unit, 32 is a bus switching control unit, 36 is a register for storing delay information, and 35 is a processing unit. The register 36 stores delay information having different values for each processing device. Reference numeral 33 is a signal receiving unit having a function of discriminating between a normal signal and a bus switching signal and distributing to the bus switching control unit 32 and the processing unit 35, and 34 is a signal transmitting unit. The bus switching unit 31 normally receives a signal from either of the two buses, transfers the received signal to the signal receiving unit 33, and transfers the signal from the signal transmitting unit 34 to the bus switching control unit.
It is sent to the bus 20 on the side specified by the control signal from 32.
When the bus switching unit 31 receives the bus disconnection control signal from the bus switching control unit 32, the bus switching unit 31 receives only the signal from the designated bus and transfers the signal to the signal receiving unit 33, and at the same time, the signal transmitting unit 34. From the bus switching control unit 32 to the designated bus. Furthermore, the bus switching unit 31
Becomes a normal connection mode in which a signal is received from either of the two buses according to a control signal from the bus switching control unit 32 and the signal is transferred to the signal receiving unit 33.

Next, the operation of transmitting and receiving a normal signal according to this configuration will be described. The normal signal from the bus 20 is the bus switching unit 31
The signal is transferred to the signal receiving unit 33 by the function of, and transferred to the processing unit 35 by the signal distribution function of the signal receiving unit 33. Also,
A normal signal transmitted from the processing unit 35 is transmitted from the bus switching control unit 32 to the designated side bus by the function of the bus switching unit 31 via the signal transmission unit 34.

Next, the operation when the bus switching signal is received will be described. The bus switching signal received from the bus 20
With the function of 31, even if the bus is received from any bus, it is transferred to the signal receiving unit 33. The bus switching signal is transferred to the bus switching control unit 32 by the signal distribution function of the signal receiving unit 33. When the bus switching control unit 32 receives the bus switching signal, it sends a control signal to the bus switching unit 31 to switch the buses, reads the contents of the register 36, and when the time determined from the value elapses, The bus switching completion signal is transmitted to the signal transmission unit 34
And to the bus 20 via the bus switching unit 31. At this time, since the control signal for switching the bus has already been sent to the bus switching unit 31, the bus switching completion signal is sent to the bus switching control device 10 through the bus that has been switched and is in use. Further, the normal signal from the processing unit 35 also receives the bus switching signal, and from the time when the bus switching control unit 32 sends the bus switching control signal to the bus switching unit 31, the bus that has been switched and is in use. Through the bus switching control device 10.

Since the bus switching control device 10 operates as described above, when the bus switching signal is sent from the bus switching control device 10, the bus switching is promptly performed, and the bus switching completion signal is delayed based on the delay information different for each processing device. Therefore, it is possible to prevent the bus switching completion signal from being concentrated and reaching the bus switching control device 10 to fill the reception buffer 11 and prevent the reception completion signal from being received.

Even when the number of buses is three or more and the bus switching signal is transferred using a different bus from the normal signal, the bus switching function for transferring the bus switching signal is changed to the bus switching control unit 32 by the same configuration. By providing the bus switching unit 31 with the bus for the normal signal transfer and the bus for the bus switching signal,
It is possible to perform the switching promptly and without the bus switching completion signal reaching the bus switching control device 10 in a concentrated manner and being unable to receive the bus switching completion signal.

FIG. 2 shows a configuration example for explaining the second embodiment of the present invention (configuration corresponding to claim (2)), in which there are two buses and A configuration example is shown in which one bus is used as a current one and the other bus is used as a spare, and a bus switching signal is transferred using the same bus as a normal signal.

The difference from the embodiment shown in FIG. 1 is that the register 36 for storing delay information is not provided, the bus switching control unit 32 receives the bus switching signal from the signal receiving unit 33, and sends the control signal to the bus switching unit 31. After that, the address which the signal receiving unit 33 originally has and which is different for each processing device is read, and at the time when a predetermined time elapses from this, a bus switching completion signal is sent to the signal transmitting unit
And sending to the bus 20 through the bus switching unit 31.

With such a configuration, a normal signal can be transmitted / received as in the configuration shown in FIG. That is, the normal signal from the bus 20 is transferred to the signal receiving unit 33 by the function of the bus switching unit 31, and the processing unit 35 is transferred by the signal distribution function of the signal receiving unit 33.
Transferred to. Further, the normal signal transmitted from the processing unit 35 is transmitted to the designated bus from the bus switching control unit 32 by the function of the bus switching unit 31 via the signal transmission unit 34.

When the bus switching signal is received, the bus switching signal received from the bus 20 is transferred to the signal receiving unit 33 regardless of which bus is received by the function of the bus switching unit 31. The bus switching signal is sent to the bus switching control unit by the signal distribution function of the signal receiving unit 33.
Transferred to 32. When the bus switching control unit 32 receives the bus switching signal, it sends a control signal to the bus switching unit 31 to switch the buses, reads the address of the processing device in the signal receiving unit 33, and When the time determined from the value has elapsed, the bus switching completion signal is sent to the signal transmission unit 34.
And to the bus 20 via the bus switching unit 31. At this time,
Since the control signal for switching the bus is sent to the bus switching unit 31, the bus switching completion signal is sent to the bus switching control device 10 through the bus that has been switched and is in use. Further, the normal signal from the processing unit 35 also receives the bus switching signal, and from the time when the bus switching control unit 32 sends the bus switching control signal to the bus switching unit 31, the bus that has been switched and is in use. Through the bus switching control device 10.

Since the bus switching control device 10 operates as described above, when the bus switching signal is sent from the bus switching control device 10, the bus switching is promptly performed, and the bus switching completion signal is delayed based on the delay information different for each processing device. Therefore, it is possible to prevent the bus switching completion signal from being concentrated and reaching the bus switching control device 10 to fill the reception buffer 11 and prevent the reception completion signal from being received.

Even when the number of buses is three or more and the bus switching signal is transferred using a different bus from the normal signal, the bus switching function for transferring the bus switching signal is changed to the bus switching control unit 32 by the same configuration. By providing the bus switching unit 31 with the bus for the normal signal transfer and the bus for the bus switching signal, the bus switching completion signals arrive at the bus switching control device 10 in a concentrated manner, and the bus switching completes. It is possible to switch without losing the completion signal.

(5) Effects of the Invention As described above, according to the present invention, when a bus switching signal is sent from the bus switching control device to the processing device, the bus switching is performed promptly and a plurality of processing devices are operated. Since the bus switching completion signal is sent to the bus switching control device after being delayed for a different time for each processing device, the bus switching completion signal is prevented from being concentrated on the bus switching control device and the bus switching completion signal is ensured. There is an advantage that a bus switching method that can receive and guarantee the confirmation of bus switching can be realized with a simple configuration.

[Brief description of drawings]

FIG. 1 shows a configuration example for explaining the first embodiment, FIG. 2 shows a configuration example for explaining the second embodiment, and FIG. 3 shows a plurality of processing devices and a bus switching control device. The structural example of the system connected by the bus is shown. 10 …… Bus switching control device, 11 …… Reception buffer, 20 …… Bus, 30 …… Processing device, 31 …… Bus switching unit, 32 …… Bus switching control unit, 33 …… Signal receiving unit, 34 …… Signal transmission unit, 35 ... Processing unit, 36 ... Register.

Claims (2)

[Claims] 1. A plurality of buses connecting a plurality of processing devices are installed, and a bus switching control device for switching control of the buses is provided, and a bus switching signal from the bus switching control device to the plurality of processing devices. When all the processing devices receive a bus switching signal, the connected bus is switched and the bus switching completion signal is sent to the bus switching control device, and the bus switching completion signal is received from all the processing devices. In the bus switching method that completes bus switching by doing so, a means for storing delay information in the processing device in advance and a method for storing the bus switching completion signal based on the stored delay information when the bus switching is completed. A bus switching system characterized by providing means for delaying transmission. 2. The address information determined for each processing device is used as the delay information of the processing device, and the bus switching completion signal is delayed based on the delay information. Bus switching method.