JP2002335248A - Ieee1394 interface switching circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IEEE1394 interface switching circuit, with which the data of an IEEE1394 interface circuit can be switched to a different route inside a package without inserting/ejecting an IEEE1394 cable to be connected with a data transmitting destination. SOLUTION: By using an analog switch 4 extremely reducing internal delay time, ON resistance and load capacity in place of a three-port physical layer LSI 16 based on a conventional P1394 a draft 2.0, a route can be switched by an electric connection or disconnection while suppressing an influence to be exerted upon data 8 of an IEEE1394 interface circuit 3 as much as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an interface circuit, and more particularly to an IEEE 1394 interface switching circuit for branching and connecting different paths to an IEEE 1394 interface circuit.

[0002]

2. Description of the Related Art An IEEE 1394 interface is a serial interface having a real-time transmission function. For example, a digital video camera and a computer are used to prevent unnatural motion when transmitting moving image data requiring real-time performance. It is an interface suitable for multimedia use such as connection between devices. IEEE
The E1394 interface has a high speed of 400 Mbps and a very low amplitude level, so that an existing IC cannot be used.

The prior art relating to or using the IEEE 1394 interface bus is disclosed in, for example, Japanese Patent Application Laid-Open No. H11-177598, entitled "Hub apparatus and communication method of hub apparatus and storage medium storing computer readable program". JP-A-10-149
668, "Edit control method and control signal converter"
Etc.

FIG. 2 is a block diagram of a device including a conventional IEEE1394 interface switching circuit. This device 14 is composed of a pair of packages (PKG) 1 and 2 connected to an IEEE 1394 cable 15, a relay package 9 and an IEEE 1394 cable 17 connected between these two packages 1 and 2, respectively.

[0005] Each of the packages 1 and 2 is composed of IEEE1394.
Interface circuit 3, one pair of DS connector 5, connector 6, and 3 based on P1394adraft2.0
A port physical layer semiconductor integrated circuit (hereinafter referred to as a PHY LSI or simply LSI) 16 is included. Where IE
The EE1394 cable 15 is connected to a pair of DS connectors 5 and the IEEE1394 interface circuit 3, respectively. The connector 6 is connected to the IEEE 1394 interface circuit 3.

Next, the connection relationship between the packages 1 and 2 will be described. The relay package 9 includes a control unit 10 and connectors 12 and 13 connected to both ends thereof. Each IEEE 1394 cable 15 is connected to the DS connector 5 of the package 1 or 2, and the IEEE 1394 cable 17 is connected to the DS connector 5 of the package 1 or 2. The connector 12 of the relay package 9 is connected to the connector 6 of the package 1, and the connector 13 is connected to the connector 6 of the package 2.

A case in which the data 8 of the IEEE 1394 interface circuit 3 is switched to a different path in the package 1 will be described. The three-port LSI 16 is used as a hub, and the path is switched by inserting and removing the IEEE1394 cable 15 connected to the transmission destination of the data 8 with the DS connector 5.

[0008]

The conventional apparatus 1 described above.
No. 4 had some problems as follows. First, IE
PHY only for switching the data 8 of the EE1394 interface circuit 3 to different paths in the packages 1 and 2.
That is, the LSI 16 is used. The reason is,
The IEEE 1394 interface circuit 3 is 400 Mb
This is because the existing IC cannot be used because of the high speed and very low amplitude level of ps.

Second, when the data 8 of the IEEE 1394 interface circuit 3 is switched to a different path in the packages 1 and 2, the IEEE 8 connected to the transmission destination of the data 8 is used.
It is necessary to insert and remove the EE1394 cable 15. The reason is that the PHY LSI 16 has no function of electrically connecting and disconnecting any ports.

Third, the data of the IEEE 1394 interface circuit 3 is stored in different packages 1, 2 in the device 14.
In this case, the IEEE 1394 cable 17 is required for transmitting the data 8 between the packages 1 and 2. The reason is that the PHY LSI 16 has no function of electrically connecting and disconnecting any ports,
This is because different paths are switched by inserting and removing the EE1394 cable 15.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a relay IEEE / 1394 cable for connecting and disconnecting a PHY LSI and an IEEE 1394 cable and transmitting the signal between internal packages.
No IEEE1394 cable 17 is required, and IEEE139
IEEE139 with the four cables 15 connected
4 The data 8 of the interface circuit 3 is
To provide an IEEE 1394 interface switching circuit that enables switching to a different path within the network.

[0012]

SUMMARY OF THE INVENTION The IEEE 139 of the present invention.
The four-interface switching circuit transmits data of the IEEE 1394 interface circuit, to which a control signal from the control unit is input, to a plurality of output ports.
An analog switch for selectively transmitting output data from the E1394 interface circuit to a plurality of output ports is provided.

Further, according to the preferred embodiment of the IEEE 1394 interface switching circuit according to the present invention, the switching of the analog switch is controlled by a control signal from the control unit. Each of the packages has an IEEE 1394 interface circuit and an analog switch, and includes a pair of packages interconnected by a control unit and a relay package. The analog switch of each package transmits data of the IEEE 1394 interface circuit to a first IEEE 1394 cable connected to the IEEE 1394 cable. Transmission from one package to the other via a port or a relay package. The relay package includes a delay line having a delay time corresponding to the IEEE 1394 cable. The relay package has connectors at both ends and is interconnected with a connector provided in each package. The connector collectively connects the control unit and the delay line. Also,
The delay line of the relay package has a delay time of about 20 ns formed in a pattern.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, IEEE13 according to the present invention will be described.
Preferred embodiments of the 94 interface switching circuit will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of an apparatus using a preferred embodiment of the IEEE 1394 interface switching circuit according to the present invention. For convenience of explanation, components corresponding to the components of the related art described above with reference to FIG.
Similar reference numbers will be used.

An apparatus 14 using the IEEE 1394 interface switching circuit of the present invention comprises a pair of similar packages (PKGs) 1 and 2 and a relay package 9 connected between these two packages 1 and 2. . Package 1 is an IEEE1394 interface circuit 3,
It comprises a two-branch analog switch 4 for branch-connecting the data 8 from the IEEE 1394 interface circuit 3, a DS connector 5 for connecting an IEEE 1394 cable 15 for transmission between different devices, and a connector 6 for connection to a relay package 9. The two-branch analog switch 4 is provided with a control signal 7 from a control relay package 9.
Is entered. The analog switch 4 is an analog switch having an extremely small internal delay (delay), ON resistance, and load capacity.

The relay package 9 includes a control unit 10 for controlling the IEEE 1394 interface switching circuit 3 and the two-branch analog switch 4 of both packages 1 and 2,
It is composed of a delay line (delay line) 11 for delay adjustment of data transmission between the packages 1 and 2, and connectors 12 and 13 for connection with the packages 1 and 2. Note that the configuration of the package 2 is the same as that of the package 1, and a description thereof will be omitted.

Next, the operation of the IEEE 1394 interface switching circuit shown in FIG. 1 will be described. First, IEEE1
394 cable 15 is DS connector 5 or IEEE13
A state where the cable 94 is connected to the first port to which the cable 15 is connected will be described. According to the control signal 7 from the control unit 10 of the relay package 9, the two-branch analog switch 4
When connected to the connector 5 side, the data 8 from the IEEE 1394 interface circuit 3 is transmitted to the two-branch analog switch 4 → DS connector 5 → IEEE 1394 cable 1
5 and transmitted. This enables data transmission of the IEEE 1394 interface circuit 3 between different devices.

On the other hand, a case where the two-branch analog switch 4 is connected to the relay package 9 will be described. IEEE
Data 8 from the 1394 interface circuit 3 is transmitted via the two-branch analog switch 4 → connector 6 → connector 12 → delay line 11 → connector 13. Therefore, while the IEEE 1394 cable 15 is connected to the DS connector 5, the package 1,
Data 8 of the IEEE 1394 interface circuit 3 can be transmitted between the two. At this time, the value of the delay line 11 of the relay package 9, that is, the delay time value is
The maximum length of the EEE1394 cable 15 is (depending on the standard)
Since it is 4.5 m, the delay is set to about 20 ns in consideration of the delay of 5 ns per m.

Next, another embodiment of the IEEE 1394 interface switching circuit according to the present invention will be described. The two-branch analog switch 4 has three branches, and the delay line 11
By increasing the number of devices, the number of inter-package transmissions within the device 14 can be increased to three or more as long as the control signal 7 from the control unit 10 and the number of pins of the connectors 6, 12, and 13 can be physically increased. It is possible to increase.

The configuration and operation of the preferred embodiment of the IEEE 1394 interface switching circuit according to the present invention have been described in detail. However, such an embodiment is merely an example of the present invention and does not limit the present invention in any way. It will be readily apparent to those skilled in the art that various modifications and changes can be made in accordance with the particular application without departing from the spirit of the invention.

[0022]

As understood from the above description, according to the IEEE 1394 interface switching circuit of the present invention,
The following remarkable practical effects can be obtained. First, LS
That is, the data of the IEEE 1394 interface circuit can be switched to a different path in the package without using I. The reason is that an analog switch having an extremely small internal delay time (delay), conduction (ON) resistance, and load capacitance is used in place of the conventional PHY LSI, and the influence on the data of the IEEE1394 interface circuit is reduced and realized at low cost. This is because it is possible.

Second, the IE connected to the data transmission destination
No need to insert and remove the EE1394 cable, IEEE
That is, the data of the 1394 interface circuit can be switched to a different path in the package.
The reason is that an analog switch can be used instead of the conventionally used PHY LSI, and can be electrically connected or disconnected.

Third, the transmission of data between packages requires I
No need for IEEE1394 cable, IEEE13
It is possible to transmit data of the 94 interface circuit to different packages in the device. The reason is that an analog switch can be used instead of the conventionally used PHY LSI to be electrically connected or disconnected, and the delay can be adjusted by providing a delay line in the pattern. is there.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus using a preferred embodiment of an IEEE 1394 interface switching circuit according to the present invention.

FIG. 2 is a block diagram of a device using a conventional IEEE1394 interface switching circuit.

[Explanation of symbols]

 1, 2 Package (PKG) 3 IEEE1394 interface circuit 4 2-branch analog switch 5 DS connector 6, 12, 13 connector 7 Control signal 8 Data 9 Relay package 10 Control unit 11 Delay line 14 Device 15, 17 IEEE 1394 cable

Claims (7)

[Claims] 1. An IEEE to which a control signal from a control unit is input.
An IEEE1394 interface switching circuit for transmitting data of an E1394 interface circuit to a plurality of output ports, comprising: an analog switch for selectively transmitting data from the IEEE1394 interface circuit to the plurality of output ports. circuit. 2. The IEEE 1394 interface switching circuit according to claim 1, wherein switching of the analog switch is controlled by a control signal from the control unit. 3. A pair of packages each having the IEEE 1394 interface circuit and the analog switch, the packages being interconnected by a relay package including the control unit, wherein the analog switch of each package is: 2. The data of the IEEE 1394 interface circuit is transmitted from one package to the other package via a first port to which an IEEE 1394 cable is connected or the relay package.
Or the IEEE 1394 interface switching circuit according to 2. 4. The relay package according to claim 1, wherein said relay package comprises:
4. The IEEE of claim 3, including a delay line having a delay time corresponding to a 394 cable.
1394 interface switching circuit. 5. The I according to claim 3, wherein the relay package has connectors at both ends, and is interconnected with a connector provided on each of the packages.
EEE1394 interface switching circuit. 6. The IEEE 1394 interface switching circuit according to claim 5, wherein said connector connects said control section and said delay line collectively. 7. The IE according to claim 4, wherein the delay line of the relay package has a delay time of about 20 ns formed in a pattern.
EE1394 interface switching circuit.