JP5535273B2 - Data receiving apparatus and data transmitting / receiving method - Google Patents

Description

  The present invention relates to a data receiving apparatus and a data transmission / reception method for receiving video data via a digital interface.

  HDMI (High Definition Multimedia Interface) standard as an example of a multimedia interface between a video transmission device such as a DVD player, a digital tuner, or a set top box and a video reception device such as a TV receiver or a monitor (see Non-Patent Document 1) There is. A device having an HDMI output terminal is referred to as a source device, and a device having an HDMI input terminal is referred to as a sink device. The video transmission device is a source device, and the video reception device is a sink device. A device having an HDMI input terminal and an HDMI output terminal and having both functions of a source device and a sink device is referred to as a repeater device.

  When the source device is connected to the sink device, a + 5V power signal is transmitted to notify that the source device is connected to the sink device. The + 5V power supply signal is also a signal indicating source ready.

  When the sink device receives the + 5V power supply signal, the sink device starts preparation for receiving the video signal. When the sink device is ready, the sink device transmits a hot plug detection (HPD) signal (High signal) to the source device. The HPD (Hot Plug Detect) signal is also a signal indicating sync ready.

  The sink device has an EDID memory that stores EDID (Extended Display Identification Data) that stores video format information that can be displayed. The video format information includes video data format and resolution, display specifications such as synchronization frequency, audio data format, and audio specification data such as sampling frequency: Fs and bit length.

  When the source device receives the High level HPD signal, it reads the EDID from the EDID memory of the sink device using a DDC (Display Data Channel) line, and displays the video format information that can be displayed by the sink device written in the EDID. Read.

  Also, the source device exchanges data necessary for HDCP (High-bandwidth Digital Content Protection) authentication with the sink device through the DDC line. The data necessary for authentication includes, for example, HDCP key information. In this example, it is assumed that HDCP key information is stored in the storage area of the sink device. Authentication means that the source device confirms that the sink device is authorized to receive the video signal. When authentication is established, the source device encrypts the video with the shared secret key and transmits it to the sink device.

  After reading and authenticating the EDID, the source device transmits video, audio, and AUX information suitable for the format of the sink device to the sink device using the TMDS (Transmission Minimized Differential Signaling) method.

  The HDMI standard also defines an arbitrary standard related to mutual control between devices called CEC (Consumer Electronics Control). The HDMI devices are connected in a tree shape through repeaters. CEC uses a single-wire low-speed serial bus. An example of a function realized by CEC is one-touch play that controls a sink device from a source device. When a source device such as a DVD is set to the playback mode (the playback button is pressed), the sink device such as a TV receiver is controlled from the source device, and the sink device is automatically turned on as necessary to set the signal path. It is automatically set to the own device (DVD) side, and the playback video can be displayed on the sink device.

  All devices must have a physical address in order to identify a device and control the switch to set the signal path. The physical address of the source device is written in the EDID of the sink device or repeater device. When a device is newly connected to or removed from the interconnection tree and the configuration of the tree changes, physical address detection is performed. All sink devices and repeater devices detect and propagate physical addresses. If the tree structure has a maximum of 5 levels, the address is 4 digits and n. n. n. expressed as n. The sink device or repeater device serving as the root generates 0.0.0.0 as its own physical address. The source device or repeater device reads its own physical address from the EDID memory of the connected sink device.

  The timing at which the source device or repeater device reads the physical address of its own device is when the High level HPD signal transmitted from the sink device or repeater device is received in response to the transmitted +5 V power supply signal. The sink device is provided with a plurality of HDMI ports, but only one EDID memory is provided. Therefore, depending on the power on / off state of each device and the selection state of the switch, there may occur a situation in which the source device or repeater device cannot correctly read its own physical address.

  For example, when the source device 1 is connected to the port 1 of the sink device (port 1 is selected) and the HPD signal becomes High, the source 1 acquires the physical address 1.0.0.0. Source 1 continues to hold the physical address even if the HPD signal subsequently returns to Low. Since the HPD is Low, even if the source 1 is extracted from the port 1, the sink device cannot detect it. Therefore, even if the source 1 is connected to the port 2 after that, the port 2 is not selected and the HPD signal is Low, and the source 1 holds the physical address of the port 1 and the correct physical address (2.0.0). .0) cannot be obtained. For this reason, there is a possibility that correct CEC control cannot be performed.

High-Definition Multimedia Interface Specification Version 1.3a

  As described above, a data receiving apparatus that receives video data via a conventional digital interface, for example, HDMI, needs to exchange physical addresses with the data transmitting apparatus for mutual control between devices. There is a problem that the data transmission device cannot read the physical address of the data reception device depending on the power supply state of the device and the selection state of the switch that selects the device.

  An object of the present invention is to connect to a plurality of input ports in a data receiving apparatus including a plurality of input ports conforming to a predetermined digital interface standard and a switch for selecting an input signal from any of the plurality of input ports. It is intended to cause the data transmission apparatus to read the physical address appropriately.

A data receiving apparatus according to an embodiment of the present invention includes a voltage signal terminal to which a predetermined voltage signal transmitted from a data transmitting apparatus is input, a detection terminal that outputs a connection detection signal to the data transmitting apparatus, and an output from the detection terminal A switch for switching a voltage level of the connection detection signal, a data input terminal to which a data signal output from the data transmission device is input, and an address terminal for outputting a physical address to the data transmission device. Multiple ports,
A plurality of memories connected one-to-one to each of the address terminals of the plurality of ports;
Selecting means for selecting any one of the plurality of ports;
The connection detection signal output from the port to which the predetermined voltage signal is input among the plurality of ports is set to the detected voltage level regardless of whether the port is selected by the selection unit. controls the switch of the port, and when switching the port to the selecting means selects the first port of said plurality of ports to a second port of said plurality of ports, said second Control means for switching the voltage level of the connection detection signal by turning on and off the switch of the port;
It comprises.

A data transmission / reception method according to an embodiment of the present invention includes a plurality of data transmission devices having output ports conforming to a predetermined digital interface standard, a plurality of input ports conforming to the digital interface standard, and a plurality of input ports respectively. A physical address memory to be connected, and a data receiving device including a selection unit for selecting any of the plurality of input ports, and each of the plurality of ports receives a predetermined voltage signal transmitted from the data transmitting device. a voltage signal terminal input, a detection terminal for outputting a connection detection signal to the pre-Symbol data transmitter, a switch for switching the voltage level of the connection detection signal outputted from the detection terminal is output from the data transmission device A data input terminal to which a data signal is input and a physical address is output to the data transmitting device. A data transmission and reception method of a system having an address terminal, a
A predetermined voltage signal is transmitted from the data transmission device to the data reception device,
The data receiving device transmits a connection detection signal to the data transmitting device,
If the connection detection signal is a connection detection potential level, the data transmission device reads the physical address from the physical address memory, and when the connection detection signal changes from the non-connection detection potential level to the connection detection potential level, the data transmission device Detects the connection of the data input terminal and performs authentication when the connection is confirmed. If the authentication is correct, the data is transmitted to the data receiving device after being encrypted.
When the data transmission device is connected to any of the plurality of input ports, the connection detection signal of the input port is set to a connection detection potential level.

  As described above, according to the present invention, the nonvolatile physical address storage means is connected between the address terminal of each input port of the data receiving device and the switch, and output from the detection terminal of the input port to the data transmitting device. By asserting the detected connection detection signal to the detection state voltage, the data transmission device can appropriately read the physical address from the data reception device regardless of the power supply state of the data reception device and the selection state of the switch.

1 is a schematic diagram showing an entire video system according to an embodiment of the present invention. The figure which shows the circuit structure of the source device which concerns on embodiment of this invention. The figure which shows the circuit structure of the sink device which concerns on embodiment of this invention. The figure which shows the electric potential of the terminal according to the state of the sink apparatus in embodiment of this invention. The signal waveform diagram which shows the electric potential of the HPD terminal of the HDMI port in embodiment of this invention.

  Embodiments of a data receiving apparatus according to the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a diagram showing a configuration of an entire video system according to a first embodiment of the present invention.

  Video in which a plurality (three in this case) of video transmission devices (source devices) 12a, 12b, 12c having HDMI output ports conforming to the HDMI standard have a plurality of HDMI input terminals via the HDMI cables 14a, 14b, 14c It is connected to a receiving device (sink device) 10. The video transmission devices 12a, 12b, and 12c include, for example, a DVD (Digital Versatile Disc) player, a streaming video transmission device, a tuner, a set top box, and a game machine. As an example, the video receiver 10 includes a television receiver, a monitor device for a PC (Personal Computer), and the like.

  FIG. 2 shows an example of the configuration of the video transmission device 12a. The video transmission device 12a includes a display unit 20 that displays a reproduction time, an input unit 21 that can perform various operations, a storage unit 22 that stores video data 220 and the like, a control unit 23 that comprehensively controls them, It consists of an HDMI output port 24 connected to the HDMI cable 14a. The main pin arrangement of the HDM port is related to TMDS (Transmission Minimized Differential Signaling), + 5V power supply, hot plug detection (HPD), the above-mentioned DDC (Digital Data Channel), and mutual control between devices. It consists of CEC (Consumer Electronics Control). The DDC line has almost the same specifications as an I2C (Inter-Integrated Circuit) bus.

  The HDMI output port 24 includes a TMDS transmission unit 25 that transmits video, audio, and auxiliary information, and a + 5V power signal for notifying the sink device or repeater device that the connection has been established when this apparatus is connected to the sink device or repeater device. (Signal indicating source ready) Connected to an output unit 26 and an HPD signal receiving unit 27 that receives an HPD signal (indicating sync ready) indicating that the sink device or repeater device is ready to receive video information Receives EDID, which is product information of the sink device and data such as a compatible video format, and EDID receiver & HDCP authenticator 28 that authenticates the sink device, and CEC transmission / reception that transmits and receives device control signals and CEC that is a control protocol Part 29.

  FIG. 3 shows an example of the configuration of the video receiver 10. The video receiving apparatus 10 has a plurality (here, three) of HDMI input ports 32a, 32b, and 32c, and the switch 36 selects any one of the ports.

  The pin arrangement of the HDMI input ports 32a, 32b, and 32c is the same as the pin arrangement of the HDMI output port 24.

  The CEC line of each port is connected to the CEC transmission / reception unit 34 in common.

  The TMDS line and DDC line of each port are connected to each input terminal of a 3-input / 1-output switch 36. EDID memories 38a, 38b and 38c made of a nonvolatile memory are connected to each DDC line. The EDID memory may be non-volatile, and is not limited to the flash memory, but may be a RAM to which a hard disk or a backup power source is connected. The EDID memories 38a, 38b, and 38c store physical addresses assigned to the source devices connected to the ports. For example, when the physical address of the sink device is 1.0.0.0, 1.1.0.0 is stored in the EDID memory 38a, 1.2.0.0 is stored in 38b, and 1 is stored in 38c. .3.0.0 is stored.

  The + 5V line of each port is connected to the EDID memories 38a, 38b, 38c. The HPD line of each port is connected to the + 5V line via switches 42a, 42b and 42c. Connection points between the switches 42a, 42b, 42c and the EDID memories 38a, 38b, 38c are connected to the ground potential via pull-down resistors 40a, 40b, 40c. The switches 42a, 42b, and 42c are always on, and are turned off for a short period of time in conjunction with the switching of the switch 36 and the change in the state of the sink device.

  The TMDS line of the HDMI input port selected by the switch 36 is connected to the TMDS receiving unit 46, and the DDC line of the selected HDMI input port is connected to the EDID transmission unit & HDMI CP authentication unit 58.

  The video signal output from the TMDS receiver 46 is supplied to the display panel 54 via the video processor 52, and the audio signal is supplied to the speaker 50 via the D / A converter 48.

  The overall control of the sink device is performed by the control unit 66.

  FIG. 4 shows the potential of each terminal according to each state of the sink device and the availability of the operation of each part.

  The standby state is a state where the power is on but the display is off. In this state, the HPD signal is High, EDID reading is permitted (OK) regardless of the selection / non-selection state of the switch 36, and HDCP authentication is performed. The NG and TMDS potentials are low.

  As described above, the + 5V line from the source device is connected to the HPD line in the sink device 10, and the HPD line is further connected to the ground potential via the pull-down resistor, so that the source device is connected to the HDMI input port. As long as the HPD line is + 5V (High). Since the HPD line is + 5V, the source device can read (OK) the EDID memories 38a, 38b, and 38c.

  However, since it is not necessary for the source device to perform HDCP authentication in the standby state, HDCP authentication is not possible (NG). Similarly, since video information is not transmitted from the source device to the sink device in the standby state, the TMDS potential is Low.

  When the sink device is in an on state (in the case of a TV receiver, the display unit is in an on state), there are terminals whose states differ depending on whether or not the switch 36 has selected a port.

  As described above, the + 5V line from the source device is connected to the HPD line in the sink device 10, and the HPD line is further connected to the ground potential via the pull-down resistor, so that the source device is connected to the HDMI input port. As long as the port is selected or not, the HPD line is + 5V (High). Since the HPD line is + 5V, the source device can read (OK) the EDID memories 38a, 38b, and 38c regardless of whether the port is selected or not.

  However, since the HDCP authentication using the DDC line only needs to be performed with the source device connected to the HDMI input port selected by the switch 36, HDCP authentication for the non-selected port is not allowed (NG) and is selected. The HDCP authentication for the designated port is permitted (OK). Similarly, since video information is transmitted from only the source device selected by the switch 36 to the sink device, the TMDS potential is set to the High level only for the selected port, and the TMDS potential for the non-selected port is Low. Is a level. However, the TMDS potential related to the non-selected port is not limited to the Low level, and may be set to the High level.

  When the source device is connected to one of the input ports of the sink device, a + 5V power signal is transmitted from the source device. The + 5V power supply signal is folded in the sink device and transmitted to the source device as an HPD signal. As shown in FIG. 4, the HPD signal is always at the high level (connection detection state) regardless of the selection state of the switch 36 or the operation state of the sink device.

  When the source device receives the High level HPD signal, it reads the EDID from the EDID memory of the sink device using the DDC line, and reads the physical address written in the EDID and the video format information that can be displayed by the sink device. . Further, when the HPD signal changes from Low level to High level, the source device exchanges HDCP key information necessary for HDCP authentication with the sink device through the DDC line. HDCP key information is also stored in the EDID memory of the sink device. When the authentication is established, the source device encrypts the video data 220 with the shared secret key, and transmits it to the sink device by the TMDS method suitable for the format of the sink device.

  In this way, when an EDID memory that stores physical addresses is connected to a plurality of HDMI input ports, and a source device is connected to the HDMI input port, the + 5V power signal is output even if the switch 36 is not selected. In response, a High level HPD signal is transmitted to the source device, so that the source device can read its physical address even in a non-selected state. Further, even when the sink device is in a standby state, the source device can read its own physical address. For this reason, the physical address required for CEC control can be obtained with certainty.

  In addition, since the HDCP authentication unit 58 to which only the HDMI input port selected by the switch 36 is connected cannot be authenticated when the sink device is in standby, it is possible to prevent unnecessary authentication.

  In the case of authentication NG, if the source device is configured to display an alert such as an authentication error, the High / Low of the TMDS potential is checked, and if HPD = High and TMDS = Low, HDCP = NG But no alert display.

  As shown in FIG. 4, the HPD terminal is always High, but in the HDMI standard, HDCP authentication is started in response to the change of the HPD signal from Low to High level. Therefore, in the state of FIG. 4, authentication is not performed when the HDMI port is switched or when the state of the sink device changes (from standby to on).

  In order to solve this problem, as shown in FIG. 5, the HPD line related to the port that has changed from non-selected to selected in response to switching of the switch 36 (changing the port from non-selected to selected) is instantaneous (for example, , 500 milliseconds) is set to the Low level and then returned to the High level again. This is realized by turning off the switch 42 for a moment when the switch 36 is switched under the control of the control unit 66. The switches 42a, 42b, and 42c are always on, and are turned off for a moment when the port is switched from non-selected to selected. Even when the sink device changes from the standby state to the on state, the switch 42 connected to the selected HDMI port is turned off for a moment under the control of the control unit 66.

  As a result, although the HPD terminal is always at the High level, authentication is performed when the HDMI port is switched or when the state of the sink device changes, preventing fraud and obtaining a correct encryption / decryption key.

  As described above, according to the first embodiment, the physical address can be appropriately notified to the source devices connected to all the HDMI input ports.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. For example, the transmission method of the High level HPD signal is not limited to the example of FIG. 3 and can be variously changed. For example, a + 5V signal is generated from the power supply of the sink device, and when the sink device is in operation, the + 5V signal is output regardless of whether the + 5V power signal is received from the source device or after confirming the reception of the + 5V power signal. It may be sent to the source device.

  Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  Further, the present invention provides a computer-readable recording recording a program for causing a computer to execute predetermined means (or for causing a computer to function as predetermined means or for causing a computer to realize predetermined functions). It can also be implemented as a medium.

  DESCRIPTION OF SYMBOLS 10 ... Sink device (display device), 12a, 12b, 12c ... Source device (video transmitter), 14a, 14b, 14c ... HDMI cable, 32a, 32b, 32c ... HMDI port, 34 ... CEC transmission / reception unit, 36 ... Switching 38a, 38b, 38c ... EDID memory, 40a, 40b, 40c ... pull-down resistor, 42a, 42b, 42c ... switch, 46 ... TMDS receiver, 60 ... + 5V power signal receiver, 62 ... HPD signal transmitter & HDCP authentication Part, 64... EDID transmission part.

Claims (15)

A voltage signal terminal to which a predetermined voltage signal transmitted from the data transmission device is input, a detection terminal for outputting a connection detection signal to the data transmission device, and a voltage level of the connection detection signal output from the detection terminal are switched. A plurality of ports each having a switch, a data input terminal to which a data signal output from the data transmission device is input, and an address terminal that outputs a physical address to the data transmission device;
A plurality of memories connected one-to-one to each of the address terminals of the plurality of ports;
Selecting means for selecting any one of the plurality of ports;
The connection detection signal output from the port to which the predetermined voltage signal is input among the plurality of ports is set to the detected voltage level regardless of whether the port is selected by the selection unit. When the switch of the port is controlled and the port selected by the selection unit is switched from the first port of the plurality of ports to the second port of the plurality of ports, Control means for switching the voltage level of the connection detection signal by turning on and off the switch of the port;
A data receiving apparatus comprising: When the data transmission device is connected to the first port, the control means sets the connection detection signal of the port to a voltage level of a detection state,
When the second input port is changed from the non-selected state to the selected state by the selection unit, after the connection detection signal output from the detection terminal of the input port is set to the voltage level of the non-detected state for a certain period, 2. The data receiving apparatus according to claim 1, wherein the switch is turned off and turned on so that the voltage level of the detection state is set again. When the data transmission device is connected to the first input port, the control means sets the connection detection signal of the port to a voltage level of a detection state,
When the data reception device is turned on from the standby state, after the connection detection signal output from the detection terminal of the input port selected by the selection unit is set to the voltage level of the non-detection state for a certain period, 2. The data receiving apparatus according to claim 1, wherein the switch is turned off and turned on so that the voltage level of the detection state is set again.   A voltage signal terminal to which a predetermined voltage signal transmitted from the data transmission device is input, a detection terminal for outputting a connection detection signal to the data transmission device, and a voltage level of the connection detection signal output from the detection terminal are switched. A plurality of ports each having a switch, a data input terminal to which a data signal output from the data transmission device is input, and an address terminal that outputs a physical address to the data transmission device;
  A plurality of memories connected one-to-one to each of the address terminals of the plurality of ports;
  Selecting means for selecting any one of the plurality of ports;
  Among the plurality of ports, the first port receives the predetermined voltage signal and the connection detection signal output from the first port not selected by the selection unit has a voltage level of the detection state. Control means for controlling the switch, and then, when the selection means selects the first port, switching the voltage level of the connection detection signal by turning off and turning on the switch of the first port;
  A data receiving apparatus comprising:   The data signal is a video data signal;
  5. The data receiving apparatus according to claim 1, wherein the video data signal is input to a selected port, and the video data signal is not input to a non-selected port. 6.   A voltage signal terminal to which a predetermined voltage signal transmitted from the data transmission device is input, a detection terminal for outputting a connection detection signal to the data transmission device, and a voltage level of the connection detection signal output from the detection terminal are switched. A plurality of ports each having a switch, a data input terminal to which a video data signal output from the data transmission device is input, and an address terminal that outputs a physical address to the data transmission device;
  A plurality of memories connected one-to-one to each of the address terminals of the plurality of ports;
  When the video data signal is not received at the first port to which the predetermined voltage signal is input among the plurality of ports, the connection detection signal output from the first port is set to the detected voltage level. Control for switching the voltage level of the connection detection signal by controlling the switch of the port and then turning off and turning on the switch of the first port when the video data signal is received at the first port Means,
  A data receiving apparatus comprising:   The data receiving device according to any one of claims 1 to 6, wherein a voltage level in a detection state of the connection detection signal set by the control means is a voltage level of the predetermined voltage signal.   8. The data receiving apparatus according to claim 7, wherein in each of the plurality of ports, the voltage signal terminal is connected to the detection terminal, and a connection point of both terminals is connected to a reference potential via a resistor.   9. The data receiving apparatus according to claim 1, further comprising an output port for outputting a data signal input to the data input terminal.   Authentication means for performing HDCP authentication on the data transmission device;
  The switching device according to any one of claims 1 to 4, and 7 to 9, further comprising a switching unit that switches the selected port and the authentication unit to connect when the selection unit selects any one of the ports. The data receiving device according to any one of claims.   The data receiving device according to any one of claims 1 to 10, wherein the plurality of ports conform to a High Definition Multimedia Interface (HDMI) (registered trademark) standard.   12. The data receiving apparatus according to claim 1, further comprising display means for displaying a data signal output from the data transmitting apparatus and input to the data input terminal. A plurality of data transmission devices having output ports conforming to a predetermined digital interface standard, a plurality of input ports conforming to the digital interface standard, a physical address memory connected to each of the plurality of input ports, and the plurality of inputs A data receiving device including selection means for selecting any of the ports,
Each of the plurality of ports includes a voltage signal terminal to which a predetermined voltage signal transmitted from the data transmission device is input, a detection terminal for outputting a connection detection signal to the data transmission device, and the output from the detection terminal. Data transmission / reception of a system having a switch for switching a voltage level of a connection detection signal, a data input terminal to which a data signal output from the data transmission device is input, and an address terminal for outputting a physical address to the data transmission device A method,
A predetermined voltage signal is transmitted from the data transmission device to the data reception device,
The data receiving device transmits a connection detection signal to the data transmitting device,
If the connection detection signal is a connection detection potential level, the data transmission device reads the physical address from the physical address memory, and when the connection detection signal changes from the non-connection detection potential level to the connection detection potential level, the data transmission device Detects the connection of the data input terminal and performs authentication when the connection is confirmed. If the authentication is correct, the data is transmitted to the data receiving device after being encrypted.
A data transmission / reception method in which when the data transmission device is connected to any of the plurality of input ports, the connection detection signal of the input port is set to a connection detection potential level.   When one of the plurality of input ports is changed from a non-selected state to a selected state by the selection unit, a connection detection signal output from a detection terminal of the input port is set to a non-connection detection potential level for a certain period. Item 14. The data transmission / reception method according to Item 13.   The connection detection signal output from the detection terminal of the input port selected by the selection means is set to the non-connection detection potential level for a certain period when the data receiving device is turned on from the standby state. The data transmission / reception method described.

Images