JP2000151752A - Controller and its controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily recognize the connection state of plural equipments by D/A converting video data and sound data outputted from an IEEE1394 interface by decoding processing, reading out a signal from an external equipment and outputting video data or sound data allowed to be decoded. SOLUTION: The input/output of various signals to/from the external equipment is executed by the IEEE1394 interface 3 through an 1394 plug 13 connected to an 1394 socket 2. At the time of confirming that information is read out from the external equipment and video data and sound data allowed to be respectively decoded by a video decoder 7 and a sound decoder 8 are outputted to a bus, a CPU 4 controls the interface 3 so as to output the video data to the decoder 7 and output the sound data to the decoder 8. A video data output part 9 D/A converts a video signal and outputs a digital signal to a monitor 11. A sound data output part 10 D/A converts a sound signal and outputs a digital signal to a speaker 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a control device and a control method for recognizing devices in a plug and play bus interface.

[0002]

2. Description of the Related Art FIG. 5 is a schematic diagram showing a schematic configuration of a system using a conventional plug and play bus interface. The system shown in FIG. 5 includes a personal computer (PC) 19, a camera 20,
A CD-ROM (Compact Disk-Read Only Memory) drive 21 and a printer 22 are connected, and a scanner 23 is connected to the printer 22. The personal computer 19 can control the scanner 23 via the printer 22. In this system, IEEE (Institute of Electrical and Electrical)
Electronic Engineers) 1394 cable 14 is used.

Here, an IEEE 1394 cable will be described. FIG. 6 is a schematic diagram showing a schematic cross section of the IEEE 1394 cable. As shown in FIG.
The 1394 cable 14 includes two shielded twisted pair wires 24 and is driven by a signal having a small amplitude.
In addition, a power supply cable 25 for a power supply line is provided, and power can be supplied to low power consumption devices and the like.

FIG. 7 is a schematic diagram for explaining transfer data in the IEEE 1394 interface.
As shown in FIG. 7, data transferred through the IEEE 1394 interface is converted into two signals, that is, data and a strobe, which is a complementary signal thereof, and transferred. The receiving device generates a clock by calculating the exclusive OR of these two signals.

[0005] In the IEEE1394 interface,
The device to be connected is called a “node” and its connection method is
Two types of "daisy chain system" and "node branching system" can be used, and up to 63 nodes can be connected in one bus environment.

In the IEEE 1394 interface, the connection of the IEEE 1394 cable 14 to the device can be performed while the device is turned on (hot state). When the node is added or removed, Automatically reconfigure the network. At this time, the IEEE 1394 interface automatically recognizes the connected node, and the connected node is managed on the interface. Thereby, there is no need for a troublesome connection procedure, and the unused port does not need to be terminated.

FIG. 8 is a schematic diagram showing addressing in the IEEE 1394 interface. In FIG. 8, the IEEE 1394 interface is 121
2-1991 Standard (CSR (Control and Status Regis
ters) Use a 62-bit width according to the architecture). The first 10 bits are called a bus ID (IDentity) and are used to identify a bus. The next six bits are
Called D and used to identify each device. The bus ID 1023 “bus # 1023” indicates the local bus node ID, and the node ID 63 “node #
“63” indicates a broadcast (notification to all areas).

[0008] The remaining 48 bits of the address become the address width given to each node. This width is available as an address space unique to each node, of which the last 28
The bit space is an area for unique data. In this space, identification of each device and designation of conditions to be used are stored. IEEE
The E1394 interface can determine what the connected device is by reading the data in this area.

Protocols used in the IEEE 1394 interface include isochronous transfer and asynchronous transfer. Isochronous transfer is based on the fact that at least one packet of data can be sent every 125 μs per channel, that talkers and listeners can be set up to 64 channels per node, and that the maximum packet size is determined by the data transfer rate. Data transfer speed is compensated.

Asynchronous transfer cannot be performed unless all isochronous transfers are completed. Also, isochronous transfer is similar to broadcast, whereas asynchronous transfer is to transfer data from point to point. Each transaction has a source and destination ID associated with it.

FIG. 9 is a schematic diagram showing the protocol architecture of the IEEE 1394 interface.
In FIG. 9, the physical layer 26 and the link layer 27 are mainly configured by hardware. The physical layer 26 directly transfers signals of the IEEE 1394 interface, and the link layer 27 has a role of an interface with an upper layer.

The transaction layer 28 and the serial bus management layer 29 are constituted by hardware such as a microcomputer and software operating on the hardware. Transaction layer 28
Performs conversion to IEEE 1394 interface commands and interfaces for transmission / reception operations based on commands of applications and operation systems connected to the host.

The serial bus management layer 29 is provided with a network management function such as control of a cycle master for managing an isochronous transfer procedure, optimization of performance, power management, transmission speed management, and configuration management.

The serial bus interface described above is suitable for transferring multimedia data (mainly video information and audio information) by isochronous transfer. In addition, since asynchronous transfer is possible at the same time, the control signal of the device can be unified, so that A
When used for connection of V (Audio Visual) devices, various signals can be transmitted and received between the devices simply by connecting the devices with a single cable.

[0015]

SUMMARY OF THE INVENTION Currently used A
Most V devices connect multimedia data separately using audio cables and video cables. In the case of a device capable of recording / reproducing, a cable twice as large is used. Therefore, the connection of the cables becomes complicated, but the connection of each device can be visually determined by following the cables.

However, in a serial bus interface such as an IEEE 1394 interface,
Since the physical wiring state does not match the logical connection state between the devices, it is difficult to visually determine the connection state between the devices. In addition, when a selector or the like is used to distinguish each device, initial settings and the like for distinguishing each device are required, but since the physical connection state is different from the logical connection state, the initial setting is not necessary. There is a disadvantage that the work is also complicated.

Accordingly, it is an object of the present invention to provide a control device capable of easily recognizing a connection state of a plurality of devices connected by an IEEE 1394 interface.

[0018]

According to the present invention, there is provided an IEEE 1394 interface for inputting / outputting a signal to / from an external device via an IEEE 1394 cable, and a decoding process for video data output from the IEEE 1394 interface. A video decoder that converts the video signal into an output video signal; a video data output unit that converts the video signal output from the video decoder to digital / analog (D / A); and outputs the audio data output from the IEEE 1394 interface. An audio decoder that performs a decoding process to convert the audio signal to an audio signal and outputs the audio signal; and an audio signal output from the audio decoder is D / A (Digital /
g) an audio data output unit for converting and outputting,
I. Reads a signal from an external device via a 394 interface and outputs video data or audio data that can be decoded to a video decoder or an audio decoder.
CPU that controls the IEEE 1394 interface
(Central Processing Unit).

Further, the present invention according to claim 2 provides the invention according to claim 1.
The control device described above is characterized in that the CPU performs control to output the video signal or the audio signal from the video data output unit or the audio data output unit only for a predetermined time.

Further, the present invention according to claim 2 is an IEEE standard.
Connected device checking means for recognizing all devices connected to the bus when a bus reset occurs due to disconnection and insertion of the 1394 cable, and whether there is a newly added device before and after the bus reset A device connection information updating unit that reads the device-specific data of the newly added device; and a device that uses the device-specific data to output data to the bus using audio data or video data or the audio data. Data existence check means for determining whether the data is data other than the video data, and decoding the audio data or the video data when the data output on the bus using the device-specific data is the audio data or the video data. Data content checking means for determining whether the data can be processed and output, and audio data. Or in the case of video data, it is characterized by comprising an input source switching means for outputting a video signal or an audio signal by a predetermined time by performing a decoding process on the audio data and video data.

[0021]

FIG. 1 is a schematic diagram showing a schematic configuration of an embodiment of a control device according to the present invention. 1, a control device 1 includes a 1394 socket 2, an IEEE1394 interface 3, and a CPU (Central Processing Uniform).
t) 4, ROM (Read Only Memory) 5, RAM (Rando
m Access Memory) 6, a video decoder 7, an audio decoder 8, a video data output unit 9, and an audio data output unit 10. Further, a monitor 11 and a speaker 12 are connected to the control device 1.

The 1394 socket 2 has IEEE 139
4 is connected to the 1394 plug 13 of the cable 14, and the input and output of various signals
IEEE1394 via the 1394 plug 13 connected to
394 interface 3.

The CPU 4 has a transaction layer 2
8 and processing related to the serial bus management layer 29 and logical connection of each device. The program that runs on the CPU 4 is stored in the ROM 5
When processing a program, R
AM6 is used.

When the CPU 4 reads information of an external device via the IEEE 1394 interface 3 and detects that audio data or video data that can be decoded by the video decoder 7 or the audio decoder 8 is output on the bus. And output the video data to the video decoder 7 and output the audio data to the audio decoder 8.
1394 interface 3 is controlled.

The video decoder 7 performs a decoding process on the video data output from the IEEE 1394 interface 3, converts the video data into a video signal, and outputs the video signal.

The video data output unit 9 converts the video signal output from the video decoder 7 into a digital / analog (D / A) signal.
The data is converted and output to the monitor 11.

The audio decoder 8 performs a decoding process on the audio data output from the IEEE 1394 interface 3, converts the audio data into an audio signal, and outputs the audio signal.

The audio data output unit 10 includes the audio decoder 8
The audio signal output from the D / A (Digital / Analo
g) Convert and output to the speaker 12.

FIG. 2 is a schematic diagram showing a schematic configuration of a video and audio system using the control device of the present embodiment. The control device 1 described above can be used for a video and audio system as shown in FIG. The monitor 11 and the speaker 12 shown in FIG. 1 are a TV (Television) receiver 1 in FIG.
5, the control device 1 is an IEEE 1394 cable 1
DVD (Digital Versatile Disk) player 1
6. LD (Laser Disk) player 17, CD (Compact)
Disk) It is connected to devices such as the player 18. Here, the control device 1 may be built in the TV receiver 15 (the monitor 11 and the speaker 12), and is not limited to the forms shown in FIGS.

FIG. 3 is a schematic diagram showing a data structure stored in a memory area of a device connected to the control device of this embodiment. Each device connectable to the control device 1 shown in FIG. 2 by the IEEE1394 cable 14 has an interface for transmitting data by the IEEE1394 cable 14. Each device has a memory area based on the CSR architecture.
The 8-bit area stores device-specific data.

As shown in FIG. 3, the device-specific data includes the presence / absence of video data and audio data, and if video data or audio data exists, data such as the encoding method of the data and the output channel number. Is stored.

When the control device 1 detects that a new device is connected by bus reset, it reads device-specific data of the connected device and reproduces video data and audio data output on the bus (decoding process). Then, control is performed so as to output to the monitor 11 and the speaker 12 for a predetermined time. This time can be arbitrarily set by the setting means provided in the control device, and can be used as a simple selector by setting the time to infinity, or set to "0". Thereby, the same operation as that of a conventional plug and play device can be performed.

FIG. 4 is a flowchart showing a signal switching process at the time of a bus reset in the control device of this embodiment. In FIG. 4, when a bus reset occurs due to disconnection and insertion of the IEEE 1394 cable 14, all devices connected on the bus are recognized (connected device check step: STEP1).

It is checked whether there is a newly added device by comparing before and after the bus reset (device connection information updating step: STEP 2). If there is no newly added device, the process ends.

When there is a newly added device (STEP
2) Read device-specific data in the CSR space of the newly added device (device-specific data reading step: STE)
P3).

From the device-specific data, it is determined whether the data output on the bus is audio data or video data or neither of them (data existence check step: STEP 4). If the data is not audio data or video data, the process ends.

If the data is audio data or video data (S
(Step 4) It is determined whether or not the data can be output after being subjected to the decoding process (data content check step: STEP5). If the decoding process cannot be performed on the data or the decoded data cannot be output, the process ends.

If audio data or video data can be output (STEP 5), a video signal or an audio signal is output for a predetermined time (input source switching step:
(STEP 6).

As described above, when the IEEE 1394 cable is used, the recognition of the device when the number of nodes increases or decreases is executed by a bus reset, and the node I
D is updated and the network node is constantly monitored. This makes it possible to recognize that a new device is connected to the terminal of any device.

Further, the CSR architecture allows each device to be recognized, and it is possible to recognize what data the device outputs. Thus, for example, when a plurality of video devices are connected using one monitor, when a connector of a certain device is connected or disconnected, or when a new device is connected, the relevant device is connected for a predetermined time. Since the data of the device can be output, the connection of the device can be recognized by outputting a video signal or an audio signal, and it is possible to determine the connection state of a plurality of devices. It can be done easily.

[0041]

According to the present invention, the connection state of a plurality of devices connected by the IEEE1394 interface can be easily recognized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an embodiment of a control device according to the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of a video and audio system using the control device of the embodiment.

FIG. 3 is a schematic diagram showing a data configuration stored in a memory area of a device connected to the control device of the embodiment.

FIG. 4 is a flowchart showing a bus reset character signal switching process in the control device of the embodiment.

FIG. 5 is a schematic diagram showing a schematic configuration of a system using a conventional plug and play bus interface.

FIG. 6 is a schematic view showing a schematic cross section of an IEEE 1394 cable.

FIG. 7 is a schematic diagram for explaining transfer data in the IEEE 1394 interface.

FIG. 8 is a schematic diagram showing addressing in the IEEE 1394 interface.

FIG. 9 is a schematic diagram showing a protocol architecture of an IEEE 1394 interface.

[Explanation of symbols]

1. Control device, 2. 1394 socket, 3. IE
EE1394 interface, 4, CPU, 5 ...
ROM, 6 RAM, 7 video decoder, 8 audio decoder, 9 video data output unit, 10 audio data output unit, 11 monitor, 12 speaker, 13
··· 1394 plug, 14 ·· IEEE1394 cable, 15 ·· TV receiver, 16 ·· DVD player, 1
7. LD player, 18 CD player, 19
Personal computer, 20 camera, 21 C
D-ROM drive, 22 printer, 23 scanner, 24 twisted pair wire, 25 power cable, 26 physical layer, 27 link layer, 28 transaction layer, 29 transaction layer・ Serial bus management layer.

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Claims (3)

[Claims] (1) IEEE (Institute of Electrical and
(Electronic Engineers) An IEEE 1394 interface for inputting and outputting signals to and from external devices via a 1394 cable, a video decoder for decoding video data output from the IEEE 1394 interface, converting the video data into a video signal, and outputting the video signal; The video signal output from the decoder is converted to D / A (Digital / Analog)
A video data output unit that converts and outputs the video data;
An audio decoder that decodes audio data output from the 394 interface, converts the audio signal to an audio signal, and outputs the audio signal; and an audio that converts the audio signal output from the audio decoder to digital / analog (D / A) output. A data output unit that reads a signal from an external device via the IEEE 1394 interface and outputs the video data or the audio data that can be decoded to the video decoder or the audio decoder to the IEEE
CPU that controls the 1394 interface (Centra
l Processing Unit). 2. The control device according to claim 1, wherein said C
A control device, wherein the PU performs control to output the video signal or the audio signal from the video data output unit or the audio data output unit only for a predetermined time. 3. A connected device check step for recognizing all devices connected to the bus when a bus reset occurs due to disconnection and insertion of an IEEE 1394 cable, and the number of newly added devices is compared before and after the bus reset. A device connection information updating step for checking whether or not the device is present; a device-specific data reading step for reading device-specific data of the newly added device; and data output on the bus using the device-specific data, A data existence check step of determining whether data or video data or data other than the audio data and the video data,
If the data output on the bus using the device-specific data is the audio data or the video data, whether the audio data or the video data is data that can be decoded and output. A data content checking step of determining whether or not the audio data or the video data, the input source switching step of performing a decoding process on the audio data or the video data and outputting a video signal or an audio signal for a predetermined time. A control method, comprising: