JPH11306127A - Electronic equipment and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform communication between two devices connected to different buses without using a new communication means by changing one of address numbers of both devices when a device having the same address number as that of a prescribed device is present on the bus of a switched destination. SOLUTION: Devices 2 and 4 usually operate separately from each other on buses 1 and 3, and in the same address number 'address 0' respectively. When the device 2 is required to perform communication with the device 4, the device 2 stops its operation on the bus 1 and gives a communication request to the device 4 by means of a request signal 5a. Thereby, the device 4 stops its operation on the bus 3 and gives permission of communication to the device 2 by means of an enable signal 5. Thus, the device 2 operates a changeover switch 6 to switch its connected destination to the bus 3 from the bus 1 by means of a bus switch signal. In this case, the device 2 uses an address number 'address 1' in order to prevent coincidence with address numbers of all devices set on the bus 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electronic device for performing communication between devices respectively existing on a plurality of buses and a control method thereof.

[0002]

2. Description of the Related Art Conventionally, there are a plurality of buses. For example, if two buses are used to communicate from a device on one bus to a device on the other bus, two buses are simply used. When the bus is connected, there is a problem that a plurality of devices having the same address number exist on the same bus and communication cannot be performed correctly. Therefore, it is common to provide a new communication means separately from the existing bus, and perform communication using the new communication means.

[0003]

However, in the above-mentioned conventional electronic equipment, there is a problem that a new communication means is required, so that the structure of the system tends to be complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has been made in view of the above circumstances. An electronic apparatus and a device which can communicate between devices existing on different buses without using new communication means. An object is to provide a control method thereof.

[0005]

An electronic apparatus and a control method thereof according to the present invention are configured as follows.

(1) In an electronic apparatus having a device connected to each of a plurality of buses, a changeover switch for switching a predetermined device existing on any one of the plurality of buses to a bus different from the bus is provided. When the predetermined device is switched to a different bus by the changeover switch to communicate with a device on the bus, a device having the same address number as the predetermined device exists on the switching destination bus Then, the address number of one of the predetermined device and the device having the same address as the predetermined device is changed.

(2) In the electronic device of (1),
A control signal line for controlling communication between two devices existing on different buses, and a switching signal line for controlling a changeover switch; preparing for communication by the control signal; and then performing the switching by the switching signal By switching the switch, the two devices are temporarily made to exist on the same bus, and communication via the bus is performed.

(3) In the electronic device of (2),
After the communication is completed, the processing at the end of the communication is performed by the control signal, the switch is switched by the switching signal, and the address number of the device whose address number has been changed is returned to the original.

(4) In a control method of an electronic device having a device connected to each of a plurality of buses, a predetermined device existing on any one of the plurality of buses is switched to a bus different from the bus. When performing communication with a device on the bus by switching to a different bus by a changeover switch, if there is a device having the same address number as the predetermined device on the switching destination bus, the predetermined device or the The address number of one of the devices having the same address as the predetermined device is changed.

(5) In the method for controlling an electronic device according to the above (4), communication is prepared by a control signal for controlling communication between two devices existing on different buses, and then switching for controlling a changeover switch is performed. The changeover switch is switched by a signal, the two devices are temporarily made to exist on the same bus, and communication via the bus is performed.

(6) In the method of controlling an electronic device according to the above (5), after the communication is completed, a process at the time of communication termination is performed by a control signal, a switching switch is switched by a switching signal, and an address number is changed. Restored device address number.

[0012]

FIG. 1 is a block diagram showing the configuration of an electronic device according to an embodiment of the present invention. In the figure,
Reference numeral 1 denotes a bus (1), which is one of the buses, and 2 denotes a device (1) connected to the bus (1). The device operates as a master during communication between the devices and has an initiative in communication. Reference numeral 3 denotes a bus (2), which is the other bus, and 4 denotes a device (2) connected to the bus (2). The device (2) operates as a slave at the time of communication between the devices and performs communication according to a command from the master. 5 is device 2 and device 4
Control signal line for controlling communication performed between
Communication request signal line 5 output from device 2 to device 4
a and a permission signal line 5b output from the device 4 to the device 2.

Reference numeral 6 denotes a switch for switching the connection of the device 2 to the bus 1 or to the bus 3. Reference numeral 7 denotes a bus switching signal line for switching the switch. Reference numeral 8 denotes a device (3) connected to the bus 1. ) And 9 are devices (4) connected to the bus 3.

FIG. 2 is a flowchart showing a control operation at the time of bus switching according to one embodiment. The flow of processing will be briefly described with reference to FIG. Note that this control operation is performed by R (not shown).
This is performed by a CPU (not shown) by a program stored in the OM in advance.

First, in step S101, it is determined whether or not a predetermined device existing on any one of the plurality of buses is required to communicate with a device on a different bus. Proceeding to step S102, it is checked whether a device having the same address exists on the communication destination bus.

If there is no device having the same address, the process proceeds to step S104, and if there is a device having the same address, the address number of the predetermined device or the device having the same address number on the communication destination bus is changed. Then, in step S104, the predetermined device is switched to a bus to which a communication destination device is connected by a switch. Then, in step S105, communication is started.

Here, the above control operation will be described in detail with reference to FIG. Each device in FIG. 1 has an address number, and the device 2 has “address 0” as an address number for operating on the bus 1 and the “address 0” as an address number for operating on the bus 3. 1 ". The device 4 operates only on the bus 3 and has “address 0” as an address number. The device 8 operates only on the bus 1 and has "address 2" as an address number. The device 9 operates only on the bus 3 and has "address 2" as an address number.

Normally, the device 2 operates on the bus 1 and the device 4 operates on the bus 3 individually. In this case, the address number of the device 2 is operating at “address 0”. Next, when it becomes necessary for the device 2 to communicate with the device 4, the operation performed on the bus 1 is stopped, and a request for communication is issued to the device 4 using the request signal included in the control signal. Do. The device 4 receiving the request signal
The operation performed on the bus 3 is stopped, communication from the device 1 is prepared, and when the preparation is completed, communication permission is given to the device 2 using the permission signal in the control signal.

The device 2 having received the communication permission switches the changeover switch 6 using the bus switching signal, and switches the connection destination of the device 2 from the bus 1 to the bus 3. Thus, preparation for communication between the device 2 and the device 4 is completed. Here, the device 2 has the right to use the bus and starts communicating with the device 4. In the communication between the device 2 and the device 4, the device 2 uses "address 1" as the address number so that the address numbers do not match all the devices on the bus 3.

When the communication is completed, the device 2 informs the device 4 via the bus 3 that the communication has been completed. The device 4 that knows the end of the communication uses the permission signal in the control signal to permit the end of the communication. Device 2 permitted to end communication
Switches the changeover switch using the changeover signal,
The device 2 is connected to the bus 1 again. When the switching of the changeover switch 6 is completed, the device 2 notifies the device 4 that the switching of the bus is completed using the request signal in the control signal. This completes the communication between device 2 and device 4, and then on a separate bus,
Continue working individually. Thereafter, as long as the device 2 operates on the bus 1, the device 2 uses “address 0” as the address number.

As described above, in this embodiment, a control signal for controlling communication and a changeover switch for switching buses are added, and the address number is changed only when communication is performed between devices respectively existing on two buses. As a result, it is possible to perform communication between devices respectively existing on two buses having the same configuration without preparing new communication means.

[0022]

As described above, according to the present invention,
A switching switch for switching a predetermined device present on any one of the plurality of buses to a bus different from the bus, and switching the predetermined device to a different bus by the switching switch and a device on the bus; When performing communication, if there is a device having the same address number as the predetermined device on the switching destination bus, either one of the predetermined device or a device having the same address as the predetermined device Is changed, it is possible to communicate between devices existing on different buses without using a new communication means, thereby preventing the system from becoming complicated. effective.

[0023] Further, it has a control signal line for controlling communication between two devices existing on different buses and a switching signal line for controlling a changeover switch, and prepares for communication by the control signal. The changeover switch is switched by a changeover signal, and the two devices are temporarily made to exist on the same bus, and the communication is performed via the bus. Therefore, the communication can be automatically performed, and the communication error can be prevented. This has the effect.

Further, after the communication is completed, processing at the end of the communication is performed by the control signal, the switch is switched by the switching signal, and the address number of the device whose address number has been changed is returned to the original. After the termination, there is an effect that communication on a normal bus can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an electronic device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a control operation at the time of bus switching according to one embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 bus 2 device 3 bus 4 device 5 control signal line 5a communication request signal line 5b permission signal line 6 switch 7 bus switching signal line 8 device 9 device

Claims (6)

[Claims] 1. An electronic apparatus having a device connected to each of a plurality of buses, wherein the switch switches a predetermined device existing on any one of the plurality of buses to a bus different from the bus. When the predetermined device is switched to a different bus by the changeover switch to communicate with a device on the bus, a device having the same address number as the predetermined device exists on the switching destination bus In this case, the electronic device changes an address number of one of the predetermined device and a device having the same address as the predetermined device. 2. A control signal line for controlling communication between two devices existing on different buses, and a switching signal line for controlling a changeover switch, wherein the control signal is used to prepare for communication. 2. The electronic apparatus according to claim 1, wherein the switch is switched by a switching signal, the two devices are temporarily present on the same bus, and communication via the bus is performed. 3. After the communication is completed, processing at the end of communication is performed by a control signal, a switch is switched by a switching signal, and the address number of the device whose address number has been changed is restored. The electronic device according to claim 2. 4. A method for controlling an electronic device having devices respectively connected to a plurality of buses, wherein a predetermined device existing on any one of the plurality of buses is transferred to a bus different from the bus. When performing communication with a device on the bus by switching to a different bus by a changeover switch, if a device having the same address number as the predetermined device exists on the switching destination bus, the predetermined device or A method of controlling an electronic device, wherein an address number of one of devices having the same address as the predetermined device is changed. 5. Preparation for communication is performed by a control signal for controlling communication between two devices existing on different buses,
5. The electronic device according to claim 4, wherein the switch is switched by a switching signal for controlling the switch, the two devices are temporarily present on the same bus, and communication is performed via the bus. How to control equipment. 6. After the communication is completed, processing at the end of communication is performed by a control signal, a switch is switched by a switching signal, and the address number of the device whose address number has been changed is restored. A method for controlling an electronic device according to claim 5.