JP2000358049A - Equipment for bus system and system device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a communication for actuation among respective devices while the bus interfaces of the respective devices are not powered on without using any other communication means than an IEEE1394 bus line and to transmit data by powering ON the bus interfaces of the respective devices according to need. SOLUTION: The power sources of IEEE1394 bus I/F parts 12 and 22 of devices 1 and 2 are normally in a off-state and communication I/F parts 17 and 27 having IEEE1394 ports connected to command interpreter parts 16 and 26. Bus lines 7a to 7c are used to send a communication request from the device 1 to the device 2. The device 2 once receiving the communication request sends a response to the device 1 to turn on the power source of the bus I/F part 22, thereby connecting the port to the bus I/F part 22. The device 1 once receiving the response connects the port to the bus I/F part 12 to turn on the power source of the bus I/F part 12. Consequently, the devices 1 and 2 become able to have an IEEE1394 communication.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a bus system device constructed by four buses (IEEE 1394 standard serial bus) and devices constituting the bus system device.

[0002]

2. Description of the Related Art It is considered that various devices (nodes) provided in a home or mounted on a car are connected by an IEEE 1394 bus to construct a bus system and transmit data between the devices. Have been.

[0003] The IEEE 1394 bus allows data to be transmitted directly between devices without mediation of a personal computer, has a high degree of freedom in device connection, has a large number of connectable devices, and has a large number of connectable devices. Connection,
It has features such as being removable. The data transmission speed has recently been increased to the order of G bits / sec.

[0004]

However, the conventional IEEE has not been developed.
The E1394 bus system can transmit data between devices only when power is supplied to the bus interface of each device connected by a bus line (bus cable). Is not turned on, between the device and other devices or between other devices through the device,
Data cannot be transmitted.

However, if the power of the bus interface of each device is always turned on in order to transmit data between the devices, the power consumption increases, and in particular, a battery as a power source as in a vehicle-mounted system is used. This is not preferable in a bus system using.

For this reason, it is conceivable to control the power supply of the bus interface of each device by a communication means with low power consumption different from the IEEE 1394 bus line. However, this method has a drawback that the system becomes complicated and high cost. is there.

Therefore, according to the present invention, it is possible to perform startup communication between devices without using a communication means different from the IEEE 1394 bus line and without turning on the power to the bus interface of each device. This enables the power supply of the bus interface of each device to be turned on when necessary to transmit data without increasing the complexity and cost of the system, thereby realizing power saving. It was made.

[0008]

A bus system device according to the present invention is provided with an IEEE 1394 bus interface and is connected to another device via an IEEE 1394 bus line. All of them are used as the start-up communication line, and the start-up communication line is used for the above-mentioned IEEE13.
It has a communication interface for performing start-up communication with other devices connected by a 94 bus line.

In the bus system device of the present invention configured as described above, each of the devices is not powered on to the bus interface of each device without using any communication means different from the IEEE 1394 bus line. Starting communication can be performed between the devices, and data can be transmitted by turning on the power of the bus interface of each device when necessary.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Configuration of Bus System Equipment and Bus System Apparatus] FIG. 1 shows an example of a bus system equipment and a bus system apparatus according to the present invention. The bus system device is one in which devices 1 and 2 are connected by an IEEE 1394 bus 7.

As the IEEE 1394 bus line (bus cable), two sets of four signal lines (TPA line and TP line) are used.
B line) and a pair of two power supply lines (CPS lines) with 6 pins, and two pairs of four signal lines with only four signal lines. In the example of FIG. This is the case of a 6-pin signal line 7a, 7b and a pair of power supply lines 7c.

The device 1 includes a device control unit 10, an application unit 11, an IEEE 1394 bus I / F unit 12, a communication control unit 15, and the like. In the following description and drawings, an interface is referred to as an I / F unit.

The device control unit 10 is constituted by a microcomputer system having a CPU, a RAM, a ROM, and the like, controls a power supply of each unit of the device 1, controls communication between the device 1 and other devices, and the like. Control.
However, when the device 1 is connected to another device to form a bus system, the IEEE 1394 bus I / F unit 12
Except for, the power of the other parts is turned on and the standby state is set.

The application unit 11 includes the device control unit 1
The application program is executed by application control between 0 and 0.

The IEEE 1394 bus I / F section 12 includes an I / F
It implements IEEE 1394 communication by the IEEE 1394 bus 7, and is configured by a link layer unit 13 and a physical layer unit 14.

The communication control unit 15 is directly controlled by the device control unit 10 and performs communication between the device 1 and another device without using the IEEE 1394 protocol. The communication control unit 15 includes a command interpreter unit 16 and a communication I / F. It is constituted by the unit 17.

The command interpreter 16 converts the transmission command from the device controller 10 into a data format that can be transmitted on the IEEE 1394 bus 7 and converts the transmission command into an IEEE 139 data format.
4 converts the received command transmitted from the other device to the IEEE 1394 bus 7 into a data format that can be processed by the device control unit 10 and transmits the converted command to the device control unit 10. Communication I / F unit 1 as described later in order to selectively perform communication between the terminal and the IEEE 1394.
7 IEEE 1394 ports.

The communication I / F unit 17 is an I / F unit for performing communication directly on the IEEE 1394 bus 7 without passing through the link layer unit 13 and the physical layer unit 14 of the IEEE 1394 bus I / F unit 12. .

In FIG. 1, the communication I / F unit 17 is connected to the IEEE 13
Although shown separately from the 94 bus I / F section 12, it is desirable that the communication I / F section 17 be included in the IEEE 1394 bus I / F section 12. However, IEEE 139
When the power of the link layer unit 13 and the physical layer unit 14 of the 4-bus I / F unit 12 is off, the communication control unit 1
In order to enable the communication by the I / F 5, the power supply of the communication I / F unit 17 is independent of the link layer unit 13 and the physical layer unit 14 of the IEEE 1394 bus I / F unit 12, or
The configuration is such that passive operation is possible. In the following, the IEEE 1394 bus I / F is referred to as a communication I / F.
It does not include the F part.

Although the command interpreter 16 is shown separately from the device controller 10 in FIG. 1, it is desirable that the command interpreter 16 be included in the device controller 10.

Even when the power of the IEEE 1394 bus I / F unit 12 is off, communication by the communication control unit 15 is performed. Therefore, the communication I / F unit 17 prevents the levels of the bus lines 7a to 7c from being fixed. , As required, IEEE
The buffering and bias control of the 1394 bus 7 are performed. However, IEEE1394 bus I / F
If the unit 12 has this function, it is not necessary.

The device 2 also includes a device control unit 20, an application unit omitted in FIG. 1, an IEEE 1394 bus I / F.
Unit 22, command interpreter unit 26 and communication I /
The device having the F section 27 is configured in the same manner as the device 1.

As a bus system device, if necessary, devices other than the device 2 are connected to the device 1 according to the IEEE 1394 standard.
A device other than the device 1 is connected to the device 2 by an IEEE 1394 bus. In this case, the other devices are configured similarly to the devices 1 and 2.

FIG. 2 shows an example of a case where a signal line of the IEEE 1394 bus is used as a start-up communication line.

In this example, the communication I / F unit 17 of the device 1
Connects the ports (drivers and receivers) 19a and 19b of the signal lines 7a and 7b of the IEEE 1394 bus 7 with the command interpreter unit 16 and the IEEE 1394 bus I / F.
Switches 18a and 18b that are distributed and connected to the unit 12
The switches 18a and 18b are switched to the command interpreter unit 16 in a standby state in which communication for startup is performed by a port switching signal from the command interpreter unit 16, and the switches 18a and 18b are switched to the IEEE 1394 bus I when performing IEEE 1394 communication.
Switch to the / F section 12 side.

When the IEEE 1394 bus 7 has a power line 7c, power can be supplied from one of the devices 1 and 2 to the other by the power line 7c, but as shown by a thin line in FIG. 7c port 19c is connected to the command interpreter 16 and the IEEE 1394 bus I.
A switch 18c is provided which is separately connected to the / F unit 12, and the switch 18c is switched in the same manner as the switches 18a and 18b, so that the power supply line 7c can also be used as a start-up communication line. In this case, IEEE 1394
When communication is performed, the devices 1 and 2 are connected by the power line 7c.
From one IEEE 1394 bus I / F section to the other
Power can be supplied to the EE1394 bus I / F unit.

(When Only Power Supply Line is Used as Startup Communication Line) When the IEEE 1394 bus has a power supply line, only that power supply line can be used as a start up communication line.

FIG. 3 shows an example of this case.
Is an IEEE1 comprising signal lines 7a and 7b and a power supply line 7c.
This is a case in which the device 3 is connected to the device 2 by a 394 bus and is connected to the device 3 by an IEEE 1394 bus including signal lines 8a and 8b and a power supply line 8c.

In this example, the communication I / F unit 17 of the device 1
Connects the power supply lines 7c and 8c to the command interpreter unit 16.
And the power lines 7c, 8c
Switches 18d and 18e for switching the connection to the 1394 bus I / F unit 12 on and off are provided, and the switches 18d and 18e are in a standby state in which communication for startup is performed by a port switching signal from the command interpreter unit 16.
Is turned off, and switches 18d and 18e are turned on when performing IEEE1394 communication. Signal lines 7a, 7b
And 8a and 8b are IEEE 1394 bus I / F units 1
Connect directly to 2. In this example, when the communication of IEEE 1394 is performed, the devices 1 and 2 are connected by the power lines 7c and 8c.
Power can be supplied from one or two IEEE 1394 bus I / F sections to the other two IEEE 1394 bus I / F sections.

FIG. 4 shows another example in which only the power supply line is used as the start-up communication line. In this example, the communication I / F unit 17 of the device 1 includes a switch 18 as in the example of FIG.
The power lines 7c and 8c are directly connected to the command interpreter unit 16 without providing the d and 18e.
Power is supplied to each unit including the EE1394 bus I / F unit 12 irrespective of the power supply lines 7c and 8c.

When only the power supply line is used as the start-up communication line as in the example of FIG. 3 or FIG. 4, the start-up communication must be performed without paying attention to the impedance or the like, and therefore without using a buffer or the like. Can be.

(Communication for Starting by Controlling Bias Voltage to Signal Line) By controlling the bias voltage to the signal line of the IEEE 1394 bus, communication for starting can be performed.

FIG. 5 shows an example of this case. In this example, in the port portion of the IEEE 1394 bus 7, the signal line 7a is pulled up to a bias voltage by connecting the plus side and the minus side to the bias line 31 via the resistors R1 and R2, and 7b, the plus side and the minus side are connected to the line 32 via the resistors R3 and R4, and the line 32 is grounded via the resistor R5 and the capacitor C.
The terminal is connected.

The voltage supplied to the bias line 31 from the transmission side of the command interpreter unit 16 of the device 1 via the buffer 33 is controlled, and the bias voltage to the signal line 7a is controlled. Is transmitted to the other device, the bias voltage to the signal line 7b is controlled by the other device, and the voltage supplied from the line 32 of the device 1 to the receiving side of the command interpreter unit 16 via the buffer 34 Is controlled, the transmission from another device is received by the device 1.

However, if the signal lines 7a and 7b do not become high impedance during the communication for starting, a switch is provided between the IEEE 1394 bus I / F unit 12 and the signal lines 7a and 7b as shown in the figure. Connect the circuit 35,
When communication for starting is performed, the switch circuit 35 is turned off and the IEEE 1394 bus I / F unit 12 and the signal line 7a,
7b.

Transmission from another device may be directly received by the device control unit 10 without passing through the command interpreter unit 16 as in the example of FIG.

[Operation of Bus System Device and Bus System Device] The operation of the bus system device and the bus system device described above is performed by connecting the device 2 to the device 1 as shown in FIG. Are connected to the bus system device, the device 1 to the device 2 or the device 2
The following shows an example of a case where a communication request is issued to another device connected to the device. However, when making a communication request, it is assumed that the bus power supply of each device, that is, the power supply of the IEEE 1394 bus I / F unit is in an off state.

(First Example) In a first example, a device to which a communication request has been made receives a communication request from the device 1 and turns on the power of its own IEEE 1394 bus I / F. The request source device 1 receives the response from the request destination device, and receives the response from the request source device.
In this case, the power supply of the / F unit 12 is turned on, so that IEEE 1394 communication can be performed between the request source device 1 and the request destination device.

In this example, as shown in FIG. 6, the port switching operation of the command interpreter unit 16 of the device 1 determines whether or not the bus power has been turned off in step S1 as described later. When the bus power is turned off, the process proceeds to step S2 to connect the IEEE 1394 port to the command interpreter unit 16 side. For example, in the example of FIG. 2, the switches 18a and 18b (and 18c) are switched to the command interpreter unit 16 side. Similarly, in the other devices including the device 2, when the bus power is turned off, the IEEE 1394 port is connected to the command interpreter unit side. As a result, communication for starting can be performed between the devices.

Next, in step S3, it is determined whether or not a response to the communication request of the own device (device 1) has been returned from the command interpreter unit 26 of the other device (device 2) as described later. If a reply is received, the process proceeds to step S4, and the IEEE 1394 port is set to the IEEE 1394 port.
It is connected to the 94 bus I / F unit 12 side. For example, in the example of FIG. 2, the switches 18a and 18b (and 18c) are connected to the IEs.
Switch to the EE1394 bus I / F unit 12 side.

As shown in FIG. 7, the operation of the device control unit 10 of the device 1 in response to a communication request from the own device is determined in step S11 as to whether or not there is a communication request from the application unit 11 and the communication is performed. If there is a request, the process proceeds to step S12, where a communication request command is output to the command interpreter unit 16.

Next, in step S13, as described later, a response is returned from the command interpreter unit 26 of the other device (device 2), so that there is a reception notification from the command interpreter unit 16 of the device itself (device 1). If it is determined that there is a reception notification, step S14
The power of the IEEE 1394 bus I / F unit 12 is turned on.

As for the operation of the command interpreter unit 16 of the device 1 in response to a communication request from itself, as shown in FIG. 8, in step S21, it is determined whether or not there is a communication request from the device control unit 10; When there is a communication request, the process proceeds to step S22, and the IEEE 139 connected to the command interpreter unit 16 as described above is connected.
A communication request command is transmitted to four ports.

Next, in step S23, it is determined whether a response has been received from the command interpreter unit 26 of the other device (device 2). If a response has been received, the process proceeds to step S24, where the device control unit 10 is notified of reception.

On the other hand, as for the operation in response to a communication request from another device (device 1) of the device control unit 20 of the device 2, as shown in FIG. It is determined whether or not the communication request has been received through the command interpreter unit 26, and when the communication request to the own device (the device 2) has been received through the command interpreter unit 26, Step S
32, the command interpreter unit 26 is notified of the reception, and further proceeds to step S33, where the IE
The power of the EE1394 bus I / F unit 22 is turned on.

The operation of the command interpreter unit 26 of the device 2 in response to a communication request from another device (device 1) is as follows.
As shown in FIGS. 10 and 11, in step S41, it is determined whether or not there is a communication request from another device (device 1). If there is a communication request, the process proceeds to step S42, where the communication request is made. Is determined to include a communication request to the own device (device 2).

When the communication request includes a communication request to the own device (device 2), the process proceeds from step S42 to step S43, transmits the communication request to the device control unit 20, and then proceeds to step S44. If the communication request does not include a communication request to the own device (device 2), the process directly proceeds from step S42 to step S44.

In step S44, it is determined whether or not the communication request includes a communication request to another device (device other than devices 1 and 2) connected to own device (device 2). When a communication request to the other device is included, the process proceeds to step S44.
The process proceeds from step S45 to step S45, where the communication request is transmitted to the connected other device, and then the process proceeds to step S46. If the communication request to the connected other device is not included, the process directly proceeds from step S44 to step S46. Proceed to.

In step S46, when the communication request includes a communication request to the own device (device 2), and the communication request is transmitted to the device control unit 20, a response from the device control unit 20 is transmitted. If the communication request includes a communication request to another device connected to the own device (device 2) and the communication request is transmitted to another device connected to the own device (device 2), It is determined whether or not all of the transmitted responses from the other devices have been received.
Then, a reception response is transmitted to the communication request source device (device 1).

Further, the process proceeds to step S48, where it is determined whether or not the communication request from the other device (device 1) includes a communication request to the own device (device 2) as in step S42. When a communication request to the device 2) is included, step S4
8, the flow advances to step S49 to connect the IEEE 1394 port to the side of the IEEE 1394 bus I / F unit 22. If a communication request to the own device (device 2) is not included, the flow advances from step S48 to step S50 to perform other processing. do.

Other processes in step S50 include, for example,
In a case where the third and fourth devices are connected to the device 2, when a communication request is issued only from the device 1 to the third device, the IEEE 1 connection is established between the device 1 and the third device.
In the device 2, the IEEE 1394 port is bridged (or,
IEEE 1394 port to IEEE 1394 bus I / F
When the third and fourth devices are connected to the device 2, the third device and the third device are connected to the third device and the third device. When a communication request is issued to the third device and the fourth device, an IEEE 1394 port is connected to the IEEE 1394 bus so that the device 1 can perform IEEE 1394 communication between the third and fourth devices. / F unit 22 side, and the IEEE1394 bus I
The power supply of the / F section 22 is turned on.

As described above, the communication request source device 1
Receives the response from the command interpreter unit 26 of the device 2, connects the IEEE 1394 port of the own device to the IEEE 1394 bus I / F unit 12, and turns on the power of the IEEE 1394 bus I / F unit 12. When the communication request from the device 1 includes a communication request to the own device, the device 2 turns on the power of the IEEE 1394 bus I / F unit 22 of the own device by receiving the communication request, and also transmits the IEEE 1394 port. To I
Connected to the IEEE 1394 bus I / F unit 22 side,
When the communication request from the device 1 includes a communication request to the own device, the other device connected to the device 2 receives the communication request, thereby receiving the communication request from the own device.
The power of the F section is turned on, and the IEEE 1394 port is connected to the IEEE 1394 bus I / F section. When the communication request from the device 1 does not include the communication request to the own device, the device 2 performs the IEEE1394 communication between the device 1 and the request destination device connected to the own device for the communication request. It controls the state of its own so that it can do it.

Accordingly, the IEEE 1394 communication can be performed between the request source device 1 and the request destination device. After the completion of the IEEE 1394 communication, the device that has performed the IEEE 1394 communication and the I
The power of the IEEE 1394 bus I / F section of the device whose power is being turned on in the IEEE 1394 bus I / F section is turned off.

(Second Example) In a second example, the device control unit of each device includes a timer, and the device 1 that is the request source of the communication request.
Turns on the power of its own IEEE 1394 bus I / F unit 12 after a predetermined time has elapsed from the transmission of the communication request without receiving a response from the request destination device, and the request destination device receives the communication request. After a lapse of a predetermined time from the
In this case, the power of the 94 bus I / F unit is turned on, and thereby the IEEE 1394 communication can be performed between the request source device 1 and the request destination device.

In this example, as the port switching operation of the command interpreter unit 16 of the device 1, as shown in FIG. 12, in step S51, it is determined whether or not the bus power is turned off as described later. When the bus power is turned off, the process proceeds to step S52, and the
Port 94 is connected to the command interpreter 16 side. Similarly, in the other devices including the device 2, when the bus power is turned off, the IEEE 1394 port is connected to the command interpreter unit side. As a result, communication for starting can be performed between the devices.

Next, in step S53, it is determined whether or not a predetermined time has elapsed since the bus power timer in the device control section 10 was set as described later, that is, whether or not the time when the bus power was turned on was reached. If it is determined that the time to turn on the bus power has been reached, the process proceeds to step S54.
And change the IEEE 1394 port to IEEE 1394
Connected to the bus I / F unit 12 side.

As shown in FIG. 13, the operation of the device control unit 10 of the device 1 in response to a communication request from the own device determines whether or not there is a communication request from the application unit 11 in step S61. If there is a request, the process proceeds to step S62, in which a communication request command is output to the command interpreter unit 16, and furthermore, step S62
Proceeding to 63, a bus power timer in the device controller 10 is set.

Next, in step S64, the command interpreter 16 is activated by the bus power timer.
It is determined whether or not the time to turn on the bus power has passed after a predetermined time has elapsed since the communication request command was output to the host device.
Proceeding to 65, the power of the IEEE 1394 bus I / F unit 12 is turned on, and further proceeding to step S66, the bus power timer is reset.

As for the operation of the command interpreter unit 16 of the device 1 in response to a communication request from itself, as shown in FIG. 14, in step S71, it is determined whether there is a communication request from the device control unit 10 or not. If there is a communication request, the process proceeds to step S72, in which the IEEE 13 connected to the command interpreter 16 as described above is connected.
A communication request command is transmitted to port 94.

On the other hand, as for the operation in response to a communication request from another device (device 1) of the device control unit 20 of the device 2, as shown in FIG. It is determined whether or not the communication request has been received through the command interpreter unit 26, and when the communication request to the own device (the device 2) has been received through the command interpreter unit 26, Proceeding to step S82, a bus power timer in the device controller 20 is set.

Next, at step S83, the bus power timer turns on the bus power after a lapse of a predetermined time from the reception of a communication request to its own device (device 2) via the command interpreter unit 26 by the bus power timer. It is determined whether or not the time has elapsed, and when the time to turn on the bus power has been reached, the process proceeds to step S84, in which the power of the IEEE 1394 bus I / F unit 22 is turned on, and furthermore, in step S85.
Go to to reset the bus power timer.

The operation of the command interpreter unit 26 of the device 2 in response to a communication request from another device (device 1) is as follows.
As shown in FIG. 16, in step S91, it is determined whether or not there is a communication request from another device (device 1). If there is a communication request, the process proceeds to step S92, where the communication request is transmitted to the own device. It is determined whether or not a communication request to (device 2) is included.

When the communication request includes a communication request to the own device (device 2), the process proceeds from step S92 to step S93, transmits the communication request to the device control unit 20, and then proceeds to step S94. If the communication request does not include a communication request to the own device (device 2), the process proceeds directly from step S92 to step S94.

In step S94, it is determined whether or not the communication request includes a communication request to another device (device other than devices 1 and 2) connected to own device (device 2). If it includes a communication request to another device,
The process proceeds from step S95 to step S95, where the communication request is transmitted to the connected other device, and then the process proceeds to step S96. When the communication request to the connected other device is not included, the process directly proceeds from step S94 to step S96. Proceed to.

In step S96, similarly to step S92, it is determined whether or not the communication request from the other device (device 1) includes a communication request to the own device (device 2). When the communication request is included, the process proceeds from step S96 to step S97, in which the IEEE 1394 port is connected to the IEEE 1394 port.
Connected to the 1394 bus I / F unit 22 side,
If the request does not include a communication request, the process proceeds from step S96 to step S98 to perform another process.

The other processing in step S98 is the same as the other processing in step S50 in FIG. 11 in the first example.

As described above, the communication requesting device 1
After a predetermined time has passed since the transmission of the communication request,
IEEE 1394 port to IEEE 1394 bus I / F unit 1
2 side and IEEE 1394 bus I / F
When the power of the unit 12 is turned on and the communication request from the device 1 includes a communication request to the own device, the device 2 transmits the IEEE1394 of the own device after a predetermined time has elapsed from the reception of the communication request.
The power of the bus I / F unit 22 is turned on, and the IEEE
E1394 port to IEEE1394 bus I / F section 22
Side, and similarly, the other device connected to the device 2
When the communication request from the device 1 includes a communication request to the own device, the power of the IEEE 1394 bus I / F unit of the own device is turned on after a lapse of a predetermined time from the reception of the communication request, and the IEEE 1394 port is connected to the IEEE 1394 bus. Connect to the I / F part side. When the communication request from the device 1 does not include the communication request to the own device, the device 2 performs the IEEE1394 communication between the device 1 and the request destination device connected to the own device for the communication request. It controls the state of its own so that it can do it.

Therefore, after a lapse of a predetermined time from the transmission of the communication request from the device 1, the IEEE 1394 communication can be performed between the request source device 1 and the request destination device. After the completion of the IEEE 1394 communication, the device that has performed the IEEE 1394 communication and the I
The power of the IEEE 1394 bus I / F section of the device whose power is being turned on in the IEEE 1394 bus I / F section is turned off.

[Effects of the Embodiment] According to the above-described embodiment, when the communication of the IEEE 1394 is usually unnecessary, the power consumption of the IEEE 1394 bus I / F section of each device is turned off to reduce the power consumption. When necessary, such as when periodic data transmission such as traffic information and weather information, or sudden data transmission such as telephone or emergency information is required, the IEEE 1394 bus I / O of each device is required. By turning on the power supply of the / F section, IEEE1394 communication can be performed. Further, since a communication means different from the IEEE 1394 bus line is not used for controlling the power supply of the IEEE 1394 bus I / F section, the system is not complicated and the cost is not increased.

[0070]

As described above, according to the present invention, I
The start-up communication can be performed between the devices without using a communication means different from the EEE1394 bus line and without turning on the power to the bus interface of each device, thereby increasing the complexity of the system. Further, without increasing the cost, the power of the bus interface of each device can be turned on when necessary and data can be transmitted, thereby realizing power saving.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a bus system device and a bus system device of the present invention.

FIG. 2 is a diagram illustrating an example of a case where a signal line is used as a start-up communication line.

FIG. 3 is a diagram illustrating an example of a case where a power supply line is used as a start-up communication line.

FIG. 4 is a diagram illustrating another example of a case where a power supply line is used as a startup communication line.

FIG. 5 is a diagram illustrating an example of a case where a bias voltage to a signal line is controlled.

FIG. 6 is a diagram illustrating an example of a port switching operation of a command interpreter unit.

FIG. 7 is a diagram illustrating an example of an operation of the device control unit in response to a communication request from the own device.

FIG. 8 is a diagram illustrating an example of an operation of a command interpreter unit in response to a communication request from the own device.

FIG. 9 is a diagram illustrating an example of an operation of the device control unit in response to a communication request from another device.

FIG. 10 is a diagram illustrating a part of an example of an operation of a command interpreter unit in response to a communication request from another device.

FIG. 11 is a diagram illustrating a continuation of an example of the operation of the command interpreter unit in response to a communication request from another device.

FIG. 12 is a diagram illustrating another example of the port switching operation of the command interpreter unit.

FIG. 13 is a diagram illustrating another example of the operation of the device control unit in response to a communication request from the own device.

FIG. 14 is a diagram illustrating another example of the operation of the command interpreter unit in response to a communication request from the own device.

FIG. 15 is a diagram illustrating another example of the operation of the device control unit in response to a communication request from another device.

FIG. 16 is a diagram illustrating another example of the operation of the command interpreter unit in response to a communication request from another device.

[Explanation of symbols]

1, 2, 3, ... equipment, 7 ... IEEE 1394 bus, 7a,
7b: signal line, 7c: power line, 8a, 8b: signal line, 8
c: power line, 10: device control unit, 11: application unit, 12: IEEE 1394 bus I / F unit, 13: link layer unit, 14: physical layer unit, 15: communication control unit, 16: command interpreter unit, 17 … Communication I /
F unit, 20: device control unit, 22: IEEE 1394 bus I / F unit, 26: command interpreter unit, 27: communication I / F unit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tamaya Tanaka 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo F-term in Sony Corporation (reference) 5B011 EB03 HH02 MA06 5B077 AA01 NN02 5K032 DA11 DA20 DB32 5K033 DA11 DB23 DB25

Claims (7)

[Claims] 1. A device having an IEEE 1394 bus interface and connected to another device via an IEEE 1394 bus line, wherein a part or the whole of the IEEE 1394 bus line is used as a start communication line. A bus system device having a communication interface for performing startup communication with another device connected by the IEEE 1394 bus line. 2. A bus system device according to claim 1, wherein a communication request from another device is received by said activation communication line in a state where said IEEE 1394 bus interface is turned off.
A bus system device for turning on the power of the IEEE 1394 bus interface. 3. The bus system device according to claim 1, wherein a communication request is transmitted to another device by the start communication line while the power of the IEEE 1394 bus interface is turned off. A bus system device that turns on the power of the IEEE 1394 bus interface by receiving a response from another device via a communication line. 4. A bus system device according to claim 1, wherein a predetermined time elapses after a communication request is transmitted to another device by the start-up communication line while the power of the IEEE 1394 bus interface is turned off. A bus system device for turning on the power of the IEEE 1394 bus interface later. 5. The bus system device according to claim 1, wherein a power line of the IEEE 1394 bus is used as the start-up communication line. 6. The bus system device according to claim 1, wherein a start-up communication is performed by controlling a bias voltage to a signal line of the IEEE 1394 bus. 7. The bus system according to claim 1, wherein
A bus system device connected by an EEE1394 bus line.