Receiver

Abstract

To enable a transmitter device to read appropriate device information (EDID) from a receiver device with a reduced burden on a user.SOLUTION: A reception apparatus includes a memory unit that stores first device information and second device information, and a communication unit that communicates with an external device. A control unit determines to cause the external device to read the second device information, on the basis of reception of a rewrite signal for the first device information from the external device. It is possible to cause the external device (a transmitter device) to read appropriate device information (EDID) from a receiver device (a reception device) with a reduced burden on a user, and thus, user-friendliness can be increased.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This technology relates to a receiving device.

Background Art

[0002] In the current market, there are transmitting devices (source devices) that cannot decode the HF-VSDB (HDMI Forum Vendor Specific Data Block) newly defined in the EDID (Extended Display Identification Data) by HDMI (High-Definition Multimedia Interface) 2.0. Therefore, a TV receiver, which is a receiving device (sink device), has a specification in which the user manually switches between the EDID for "transmitting devices before HDMI 1.4" and the EDID for "transmitting devices compatible with HDMI 2.0". Here, HDMI 2.0 shall also include HDMI 2.0a and HDMI 2.0b. Also, HDMI 1.4 shall include HDMI 1.4a.

[0003] For example, Patent Document 1 describes HDMI 2.1. In HDMI 2.1, transmission by FRL (Fixed Rate Link) is defined. In this HDMI 2.1, image data is also packetized and transmitted. Before transmitting image data and audio data, an operation called FRL link training (FRL Link Training) is performed, and the transmission rate (clock rate) is set according to the capability of the transmission path between the transmitting device and the receiving device, including the HDMI cable.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] Currently, with the 256-byte EDID format, it's impossible to combine (merge) the EDIDs for "HDMI 2.0 compatible transmitters" and "HDMI 2.1 compatible transmitters" into a single EDID data. Therefore, it's necessary to allow switching between EDIDs for "HDMI 1.4 and earlier transmitters," "HDMI 2.0 compatible transmitters," and "HDMI 2.1 compatible transmitters."

[0006] In this situation, both HDMI 2.0 and HDMI 2.1 compatible transmitters use HDCP (High-bandwidth Digital Content Protection) 2.2 for content protection. Therefore, monitoring the operations performed by HDCP 2.2 cannot be used as a condition for determining whether to use the EDID for "HDMI 2.0 compatible transmitters" or "HDMI 2.1 compatible transmitters."

[0007] As mentioned earlier, HDMI 2.1 performs an operation called FRL link training. During this FRL link training, communication between the transmitting and receiving devices takes place via the DDC (Display Data Channel) line. Therefore, by monitoring the communication on the DDC line, it is possible to detect that HDMI transmission between the transmitting and receiving devices is about to be performed using HDMI 2.1, and this can be used as a condition for selecting the EDID for "HDMI 2.1 compatible transmitting devices".

[0008] The purpose of this technology is to enable transmitting devices to read appropriate device information (EDID) from receiving devices with minimal burden on the user. [Means for solving the problem]

[0009] The concept behind this technology is: A memory unit for storing first device information and second device information, A communications unit that communicates with external devices, The system includes a control unit that determines to have the external device read the second device information based on the reception of a rewrite signal to the first device information from the external device. It is located in the receiving device.

[0010] The receiving device of this technology may be, for example, a display device. Furthermore, the receiving device of this technology includes a memory unit for storing first device information and second device information, and a communication unit for communicating with an external device. For example, the first device information may be information included in a Status and Control Data Channel Structure (SCDC). In this case, for example, the first device information may be FRL_Rate, which is information regarding the link rate selected by the external device. Also, for example, the communication unit may communicate with the external device via a digital interface cable. In this case, for example, the digital interface cable may be a High-Definition Multimedia Interface (HDMI) cable.

[0011] The control unit decides to have the external device read the second device information based on the reception of a rewrite signal from the external device to the first device information. For example, the rewrite signal may be determined in accordance with the second device information. In this case, for example, the rewrite signal may be Max_FRL_Rate, which is information about the link rate supported by the device, as described in the second device information.

[0012] Thus, in this technology, the decision to have the external device read the second device information is made based on the reception of a rewrite signal to the first device information from the external device. Therefore, it becomes possible to automatically have the external device (transmitter) read the appropriate device information (EDID) from the receiving device (receiving equipment), thereby improving user convenience.

[0013] The rewrite signal may be transmitted according to the value of FLT_ready, which is information indicating the readiness status of the link training process, as described in the first device information. In addition, in this technology, for example, the memory unit may further store a third piece of device information, and the control unit may decide to have an external device read the third piece of device information if it does not receive a rewrite signal. In this case, for example, the second piece of device information may be information corresponding to High-Definition Multimedia Interface (HDMI) version 2.1, and the third piece of device information may be information corresponding to HDMI version 2.0.

[0014] In this case, the second and third device information may each be Extended Display Identification Data (EDID) containing an HDMI Forum Vendor Specific Data Block (HF-VSDB), which is information about the functions supported by the device. In this case, the second device information may be a 512-byte EDID obtained by combining (merging) the EDID for 4K High frame rate (HFR) and the EDID for 8K.

[0015] Furthermore, for example, the memory unit may store a fourth device information, and the control unit may decide to have the external device read the fourth device information if the external device does not correspond to the second and third device information. In this case, the control unit may decide that the external device does not correspond to the second and third device information if it does not receive a predetermined signal from the external device. In this case, the predetermined signal may be AKE_Init, which is the start signal for the authentication process with the external device. Also, for example, the fourth device information may be information corresponding to High-Definition Multimedia Interface (HDMI) version 1.4 or earlier. In this case, the fourth device information may be Extended Display Identification Data (EDID) including Vendor Specific Data Block (VSDB), which is information about the functions supported by the device. [Brief explanation of the drawing]

[0016] [Figure 1] This block diagram shows an example configuration of a transmission and reception system as an embodiment. [Figure 2] This diagram illustrates EDID for HDMI 1.4 and earlier, as well as HDMI 2.0 and HDMI 2.1. [Figure 3] This is a block diagram showing an example configuration of the data transmission unit (HDMI transmission unit) of the source device and the data reception unit (HDMI reception unit) of the sink device. [Figure 4] This figure shows an example of the link rate and the number of lanes corresponding to each link in HDMI 2.1. [Figure 5] This flowchart shows an example of the procedure for automatic EDID switching control processing in the control unit of a sink device. [Figure 6] This is a schematic diagram showing the EDID for HDMI 2.1. [Figure 7] This diagram schematically shows the SCDC data stored in the SCDC register section. [Figure 8]It is a diagram schematically showing HDCP data stored in the HDCP register section. [Figure 9] It is a diagram showing an example of the structure of “AKE_Init” and the content of main information in that structure example. [Figure 10] It is a flowchart showing another example of the procedure of EDID automatic switching control processing in the control section of the sink device. [Figure 11] It is a diagram showing an example of a UI screen for selecting either EDID for HDMI2.1 (4K HFR) or EDID for HDMI2.1 (8K).

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments for carrying out the invention (hereinafter referred to as “embodiments”) will be described. The description will be made in the following order. 1. Embodiments 2. Variations

[0018] <1. Embodiments> [Configuration Example of Transmission / Reception System] FIG. 1 shows a configuration example of a transmission / reception system 10 as an embodiment. This transmission / reception system 10 is configured by connecting a source device (transmission device) 100 and a sink device (reception device) 200. The source device 100 is, for example, a game machine, a disc player, a set-top box, a digital camera, a mobile phone, a personal computer, etc. The sink device 200 is, for example, a display device (display apparatus) such as a television receiver, a PC monitor, a projector, etc.

[0019] The source device 100 and the sink device 200 are connected via an HDMI cable 300, which is a digital interface cable. The source device 100 is provided with a receptacle 101 that forms a connector, to which a data transmission unit 102 is connected. The sink device 200 is provided with a receptacle 201 that forms a connector, to which a data reception unit 202 is connected. In addition, one end of the cable 300 is provided with a plug 301 that forms a connector, and the other end is provided with a plug 302 that forms a connector. The plug 301 at one end of the cable 300 is connected to the receptacle 101 of the source device 100, and the plug 302 at the other end of the cable 300 is connected to the receptacle 201 of the sink device 200.

[0020] The source device 100 has a control unit 103. This control unit 103 controls the entire source device 100. The data transmission unit 102 is compatible with HDMI 1.4 or earlier, HDMI 2.0, or HDMI 2.1. The sink device 200 has a control unit 203. This control unit 203 controls the entire sink device 200. This control unit 203 controls the data reception unit 202 to cause the source device 100 to read the EDID corresponding to its HDMI version.

[0021] When the control unit 203 determines that the data transmission unit 102 is compatible with HDMI 2.1, it decides to have the data transmission unit 102 read the EDID for HDMI 2.1. In this case, the data transmission unit 102 reads the EDID for HDMI 2.1 that is set in the EDID ROM in the data reception unit 202.

[0022] Furthermore, when the data transmission unit 102 determines that it supports HDMI 2.0, the control unit 203 decides to have the data transmission unit 102 read the EDID for HDMI 2.0. In this case, the data transmission unit 102 reads the EDID for HDMI 2.0 that is set in the EDID ROM in the data reception unit 202.

[0023] Furthermore, when the control unit 203 determines that the data transmission unit 102 is compatible with HDMI 1.4 or earlier, it decides to have the data transmission unit 102 read the EDID for HDMI 1.4 or earlier. In this case, the data transmission unit 102 reads the EDID for HDMI 1.4 or earlier that is set in the EDID ROM in the data reception unit 202.

[0024] As shown in Figure 2(a), in one embodiment, there is a 256-byte EDID "Standard" for HDMI 1.4 and earlier, a 256-byte EDID "Enhanced" for HDMI 2.0, and further 256-byte EDIDs "Enhanced (4K HFR)" and "Enhanced (8K)" for HDMI 2.1. Here, for example, the EDID "Enhanced" includes device information corresponding to 4K resolution video and High Dynamic Range (HDR) video with a frame rate of up to 60Hz, while the EDID "Enhanced (4K HFR)" and EDID "Enhanced (8K)" include device information corresponding to 4K (3840×2160) resolution video and 8K (7680×4320) resolution video with High Frame Rate (HFR) frames higher than 60Hz, respectively. In addition, each of the above EDIDs is sometimes called Enhanced-EDID (E-EDID).

[0025] In another embodiment, as shown in Figure 2(b), a 256-byte EDID "Standard" is used for HDMI 1.4 and earlier, a 256-byte EDID "Enhanced" is used for HDMI 2.0, and a 512-byte EDID "Enhanced (4K HFR / 8K)" is used for HDMI 2.1. This 512-byte EDID "Enhanced (4K HFR / 8K)" is a combination (merge) of the 256-byte EDID "Enhanced (4K HFR)" and the 256-byte EDID "Enhanced (8K)".

[0026] Here, the EDID for HDMI 1.4 and earlier includes a Vendor Specific Data Block (VSDB), which is vendor-specific information that stores information about the functions supported by the sink device. The EDID for HDMI 2.0 and HDMI 2.1 also includes an extended VSDB called the HDMI Forum VSDB (HF-VSDB).

[0027] "Example configuration of data transmission and data reception units" Figure 3 shows an example configuration of the data transmission unit (HDMI transmission unit) 102 of the source device 100 and the data reception unit (HDMI reception unit) 202 of the sink device 200 in the transmission / reception system 10 of Figure 1.

[0028] The data transmission unit 102 transmits differential signals corresponding to the pixel data of one uncompressed image to the data receiving unit 202 in one direction on multiple channels during the effective image section (hereinafter also referred to as the active video section as appropriate), which is the section from one vertical synchronization signal to the next vertical synchronization signal, excluding the horizontal retrace section and the vertical retrace section. It also transmits differential signals corresponding to at least audio data, control data, and other auxiliary data associated with the image to the data receiving unit 202 in one direction on multiple channels during the horizontal retrace section or the vertical retrace section.

[0029] In other words, the data transmission unit 102 has an HDMI transmitter 121. The HDMI transmitter 121 converts, for example, uncompressed image pixel data into corresponding differential signals and transmits them serially in one direction to the data receiving unit 202, which is connected via an HDMI cable 300, using three TMDS channels #0, #1, and #2.

[0030] Furthermore, the HDMI transmitter 121 converts audio data accompanying the uncompressed image, as well as necessary control data and other auxiliary data, into corresponding differential signals and transmits them serially in one direction to the data receiving unit 202, which is connected via the HDMI cable 300 using three TMDS channels #0, #1, and #2.

[0031] Furthermore, the HDMI transmitter 121 transmits a pixel clock synchronized with the pixel data transmitted on the three TMDS channels #0, #1, and #2 to the data receiver 202 connected via the HDMI cable 300 on the TMDS clock channel. Here, on one TMDS channel #i (i=0,1,2), 10 bits of pixel data are transmitted during one clock cycle of the pixel clock.

[0032] Here, TMDS coding is an 8-bit / 10-bit conversion coding that converts 8-bit data to 10-bit data. By reducing the number of transition points through comparison with the previous data, it suppresses adverse effects such as unwanted radiation while maintaining DC balance. Therefore, since the run-length encoding of the coding cannot be guaranteed in theory, DC coupling and separate clock transmission are essential.

[0033] The data receiving unit 202 receives differential signals corresponding to pixel data transmitted unidirectionally from the data transmitting unit 102 on multiple channels in the active video section, and also receives differential signals corresponding to audio data and control data transmitted unidirectionally from the data transmitting unit 102 on multiple channels in the horizontal retrace section or vertical retrace section.

[0034] In other words, the data receiving unit 202 has an HDMI receiver 221. The HDMI receiver 221 receives differential signals corresponding to pixel data and differential signals corresponding to audio data and control data, which are transmitted unidirectionally from the data transmitting unit 102 via the HDMI cable 300 on TMDS channels #0, #1, and #2, in synchronization with the pixel clock transmitted from the data transmitting unit 102 on the TMDS clock channel.

[0035] The above example shows image data, audio data, and control data transmitted via TMDS channels #0, #1, and #2, and the pixel clock transmitted via the TMDS clock channel. This is compatible with HDMI 1.4 and earlier, and HDMI 2.0. In the case of HDMI 2.1, transmission is performed using FRL lanes #0, #1, #2, and #3. In this case, the TMDS clock channel in Figure 3 becomes FRL lane #3.

[0036] In this case, data transmission is performed using fixed-rate link (FRL) packets with either three lanes (#0 to #2) or four lanes (#0 to #3). Here, FRL character coding is a 16-bit / 18-bit conversion coding that converts 16-bit data to 18-bit data, maintains DC balance, and allows clock extraction.

[0037] Figure 4 shows an example of link rates and the number of lanes corresponding to each link. Link rates identified as “1” (binary 0001) and “2” (binary 0010) utilize 3 lanes out of 4 lanes #0 to #3 (#0 to #2). In this case, lane #3 is an inactive lane. An active lane is the lane that transmits data. Link rates identified as “3” (binary 0011), “4” (binary 0100), “5” (binary 0101), and “6” (binary 0110) utilize all 4 lanes #0 to #3.

[0038] In the illustrated example, the link rate identified as “1” (binary 0001) has a bitrate of 3 Gbps per lane. The link rates identified as “2” (binary 0010) and “3” (binary 0011) have a bitrate of 6 Gbps per lane. The link rate identified as “4” (binary 0100) has a bitrate of 8 Gbps per lane. The link rate identified as “5” (binary 0101) has a bitrate of 10 Gbps per lane. Furthermore, the link rate identified as “6” (binary 0110) has a bitrate of 12 Gbps per lane.

[0039] Returning to Figure 3, the HDMI system, consisting of the data transmission unit 102 and the data reception unit 202, also has a transmission channel called DDC (Display Data Channel). This DDC consists of two signal lines (not shown) included in the HDMI cable 300, and communicates between the data transmission unit 102 and the data reception unit 202 using IIC (Inter-Integrated Circuit).

[0040] Specifically, the data transmission unit 102 has an IIC Master Block 122. The data reception unit 202 has a memory unit 222. The memory unit 222 includes an EDID ROM (Extended Display Identification Data ROM) 231, an SCDC (Status and Control Data Channel) register unit 232, and an HDCP (High-bandwidth Digital Content Protection) register unit 233.

[0041] The EDID ROM 231 contains EDID information, which is information about the configuration and capabilities of the sink device 200. This information is read to the source device 100 by the IIC master block 122 via the DDC. As a result, the source device 100 recognizes the configuration and capabilities of the sink device 200. The EDID ROM 231 can be implemented using rewritable memory such as EEPROM (Electrically Erasable Programmable Read-Only Memory) or flash memory, but it can also be implemented using RAM (Random Access Memory) or any other storage medium.

[0042] In this embodiment, when the data transmission unit 102 is determined to support HDMI 2.1, HDMI 2.0, and HDMI 1.4 or earlier, respectively, the EDID ROM 231 is set with EDIDs for HDMI 2.1, HDMI 2.0, and HDMI 1.4 or earlier, respectively, and the set EDIDs are read by the source device 100.

[0043] SCDC (Status and Control Data Channel) is a point-to-point communication protocol used by source device 100 and sink device 200 to exchange data. Note that SCDC is defined in HDMI 2.0 and later. The SCDC register section 232 consists of a group of registers that store SCDCS (SCDC Structure).

[0044] The source device 100 (data transmission unit 102) can read and write SCDCS data stored in the SCDC register unit 232 via the DDC using the IIC master block 122. The SCDCS data includes data related to the current link status and data that controls the operation of the source device.

[0045] HDCP (High-bandwidth Digital Content Protection) is an encryption technology that prevents copyrighted video content from being illegally copied while it is being transmitted to a display device. The HDCP register section 233 consists of a group of registers that store data related to HDCP. This data includes encryption keys for encrypting image data.

[0046] The source device 100 (data transmission unit 102) can read and write HDCP-related data stored in the HDCP register unit 233 via the DDC using the IIC master block 122.

[0047] Although not shown in the diagram, the HDMI cable 300 also includes a CEC (Consumer Electronics Control) line, an HPD (Hot Plug Detect) line, a reserve line, and a power line. The CEC line is used for bidirectional communication of control data between the source device 100 and the sink device 200. The HPD line is used for the source device 100 to detect the connection of the sink device 200, etc.

[0048] "EDID automatic switching control processing" Referring to the flowchart in Figure 5, an example of the procedure for EDID automatic switching control processing in the control unit 203 of the sink device 200 will be described.

[0049] In step ST1, the control unit 203 sets the EDID for HDMI 2.1 (Enhanced (4K HFR / 8K)) in the EDID ROM 231 and causes the source device 100 to read this EDID. In this case, the control unit 203 causes the source device 100 to read the HDMI 2.1 EDID set in the EDID ROM 231 by setting the HPD (Hot Plug Detect) line (not shown) to a high level.

[0050] Figure 6 schematically shows the EDID for HDMI 2.1. This EDID for HDMI 2.1 includes the data “Max_FRL_Rate”. The EDID includes the HF-VSDB (HDMI Forum Vendor Specific Data Block). The “Max_FRL_Rate” data is data within the HF-VSDB. This “Max_FRL_Rate” data is a data item that specifies the maximum link rate that the sink device 200 can support. This “Max_FRL_Rate” data is a 4-bit field that specifies the link rate identifier (see Figure 4) of the maximum link rate that the sink device 200 can support.

[0051] For example, when the data for “Max_FRL_Rate” is a value of “5”, it indicates that the sink device 200 supports the link rates associated with the link rate identifiers “1”, “2”, “3”, “4”, and “5”, but does not support the link rate associated with the link rate identifier “6”.

[0052] Additionally, the “Max_FRL_Rate” value may indicate whether the sink device 200 supports link training. For example, if the multimedia link is HDMI, the “Max_FRL_Rate” value may be “0”. In this case, the sink device 200 supports HDMI operation via HDMI 1.4 or earlier, or HDMI 2.0. In other words, if the “Max_FRL_Rate” value is “0”, the sink device 200 does not support any of the link rates shown in Figure 4.

[0053] Link training is not performed with HDMI 1.4 or earlier, or with HDMI 2.0. Therefore, a value of "0" for "Max_FRL_Rate" indicates that the sink device 200 does not support link training, while a value of "1" to "6" for "Max_FRL_Rate" indicates that the sink device 200 supports link training.

[0054] Returning to Figure 5, in step ST2, the control unit 203 sets "FLT_ready" in the SCDC data present in the SCDC register unit 232 to "1".

[0055] Figure 7 schematically shows the SCDC data stored in the SCDC register unit 232. The SCDC data includes data items in three categories: update flags, configuration parameters, and status flags. Status flags are values ​​that represent the current status of the sink device 200.

[0056] Update flags are values ​​(such as 1-bit binary values) associated with instructions in source device 100. If source device 100 supports HDMI 2.1, a source link training circuit (not shown) periodically polls the update flags, for example, every 2 milliseconds.

[0057] When one of the update flags is polled by the source link training circuit and has a value of, for example, "1", the source link training circuit executes the instruction associated with that update flag. In this way, the update flags provide a method for controlling the link training circuit of the source device 100.

[0058] The status flag includes "FLT_ready". The link training control circuit of the sink device 200 (not shown) indicates to the source device 100 that the sink device 200 is ready to start the link training process by writing "1" to "FLT_ready" as described above.

[0059] Configuration parameters are the current data transmission parameters of the HDMI link. These configuration parameters include "FRL_Rate," which is the link rate identifier for the current link rate. For example, using the link rate and link rate identifier example shown in Figure 4, "FRL_Rate" is a 4-bit field of data that stores the link rate identifier (Binary) for the link rate at which the HDMI link is currently operating.

[0060] For source device 100 compatible with HDMI 2.1, the source link training circuit reads the HDMI 2.1 EDID (see Figure 6) set in the EDID ROM via the DDC, as described above. In particular, the source link training circuit reads "Max_FRL_Rate" to determine whether the sink device 200 supports link training.

[0061] If the sink device 200 supports HDMI 1.4 or earlier, or HDMI 2.0, the sink device 200 does not support link training. In that case, the value of "Max_FRL_Rate" is "0". In this embodiment, the sink device 200 supports HDMI 2.1, and the source link training circuit reads the EDID for HDMI 2.1 (see Figure 6), so the value of "Max_FRL_Rate" is a value other than "0".

[0062] When the value of “Max_FRL_Rate” is not “0”, the source link training circuit of source device 100 and the link training control circuit of sink device 200 perform several actions to prepare the HDMI link for link training processing. The link training control circuit writes the value of 1 to “FLT_ready” to indicate that sink device 200 is ready to start link training processing.

[0063] The source link training circuit reads "FLT_ready" periodically, for example, every 2 milliseconds. When the source link training circuit reads "1" as the value of "FLT_ready", it selects a link rate and writes the identifier of the selected link rate to the "FRL_Rate" register. The source link training circuit selects a link rate that is less than or equal to the maximum link rate value specified by "Max_FRL_Rate" and is fast enough to support content transmission.

[0064] Returning to Figure 5, in step ST3, the control unit 203 determines whether the “FRL_Rate” register has been rewritten, that is, whether the link rate identifier has been written to the “FRL_Rate” register. When it determines that the link rate identifier has been written to the “FRL_Rate” register, this write occurs when the source device 100 supports link training, as described above, so the control unit 203 decides to have the source device 100 read the EDID for HDMI2.1, and in step ST4, the EDID for HDMI2.1 remains in the EDID ROM 231.

[0065] In this case, the EDID for HDMI 2.1 has already been loaded into the source device 100 (see explanation of step ST1). Therefore, at this point, it is not necessary to load the EDID for HDMI 2.1 stored in the EDID ROM 231 into the source device 100, but it may be done again if desired.

[0066] Furthermore, if step ST3 determines that no link rate identifier has been written to the “FRL_Rate” register, the control unit 203 proceeds to step ST5. As mentioned above, since “FLT_ready” is read periodically, for example every 2 milliseconds, this determination is made, for example, after a value of 1 has been written to “FLT_ready” and at least the time interval between readings of “FLT_ready” has elapsed.

[0067] In step ST5, the control unit 203 determines whether “AKE_Init” has been written. The image data transmitted from the source device 100 to the sink device 200 via the HDMI cable 300 is encrypted by HDCP (High-bandwidth Digital Content Protection). HDMI 2.0 and HDMI 2.1 use HDCP 2.2.

[0068] Source device 100 performs an authentication process with sink device 200 via DDC to determine whether the sink device 200 has legitimate HDCP processing capabilities. In HDCP 2.2, the AKE (Authentication and Key Exchange) process is performed as the first step of the authentication protocol to exchange encryption keys. "AKE_Init" is an authentication activation message sent from source device (HDCP transmitter) 100 to sink device (HDCP receiver) 200 at the beginning of this AKE process.

[0069] The sink device 200 receives "AKE_Init" from the source device 100 and writes it to the corresponding address in the HDCP register section 233. Figure 8 schematically shows the HDCP data stored in the HDCP register section 233. The HDCP data includes the "AKE_Init" data.

[0070] Figure 9(a) shows an example of the structure (syntax) of “AKE_Init”, and Figure 9(b) shows the contents of the main information (semantics) in that example structure. The 1-byte field “msg_id (=2)” is a message identifier indicating that it is “AKE_Init”. The 8-byte field “rTX [63.,0]” is a pseudo-random value. The 3-byte field “TxCaps” is a fixed value (0x02 0x00 0x00) containing version information.

[0071] Returning to Figure 5, when step ST5 determines that there is a “AKE_Init” write, the “AKE_Init” write occurs when the source device 100 adopts HDCP2.2, as described above. Since HDMI2.0 adopts HDCP2.2, the control unit 203 decides to have the source device 100 read the HDMI2.0 EDID, and in step ST6, it rewrites the EDID held in the EDID ROM 231 to the HDMI2.0 EDID (Enhanced). After this rewrite, the control unit 203 raises the HPD line to a high level, causing the source device 100 to read the HDMI2.0 EDID set in the EDID ROM 231.

[0072] Furthermore, if step ST5 determines that there is no “AKE_Init” written, the control unit 203 decides to have the source device 100 read the EDID (Standard) for HDMI 1.4 or earlier, and in step ST7, it rewrites the EDID held in the EDID ROM 231 to the EDID for HDMI 1.4 or earlier. After this rewriting, the control unit 203 raises the HPD line to a high level, causing the source device 100 to read the EDID for HDMI 1.4 or earlier set in the EDID ROM 231. This decision is made after a predetermined amount of time, for example several hundred milliseconds or more, has elapsed since the value 1 was written to “FLT_ready”.

[0073] As explained above, in the transmission / reception system 10 shown in Figure 1, the sink device 200 determines whether the source device 100 supports HDMI 2.1, HDMI 2.0, or HDMI 1.4 or earlier, sets the EDID version corresponding to the determination result in the EDID ROM 231, and has the source device 100 read it. Therefore, the user does not need to set the EDID version corresponding to the source device 100 in the EDID ROM 231 of the sink device 200, thereby improving user convenience.

[0074] <2. Variant> In the above-described embodiment, an example was shown in which the sink device 200 handles a 256-byte EDID "Standard" for HDMI 1.4 and earlier, a 256-byte EDID "Enhanced" for HDMI 2.0, and a 512-byte EDID "Enhanced (4K HFR / 8K)" for HDMI 2.1, as shown in Figure 2(b).

[0075] However, it is also conceivable that the sink device 200 handles the following EDIDs as shown in Figure 2(a): a 256-byte EDID "Standard" for HDMI 1.4 and earlier, a 256-byte EDID "Enhanced" for HDMI 2.0, a 256-byte EDID "Enhanced (4K HFR)" for HDMI 2.1, and a 256-byte EDID "Enhanced (8K)" for HDMI 2.1.

[0076] The flowchart in Figure 10 shows an example of the procedure for the EDID automatic switching control process in the control unit 203 of the sink device 200 in that case.

[0077] In step ST11, the control unit 203 sets the EDID for HDMI 2.1 (4K HFR) in the EDID ROM 231 and causes the source device 100 to read this EDID. In this case, the control unit 203 causes the source device 100 to read the HDMI 2.1 (4K HFR) EDID set in the EDID ROM 231 by setting the HPD (Hot Plug Detect) line (not shown) to a high level. This HDMI 2.1 (4K HFR) EDID also includes the "Max_FRL_Rate" data (see Figure 6).

[0078] Next, in step ST12, the control unit 203 sets "FLT_ready" in the SCDC data present in the SCDC register section 232 to "1". The source link training circuit of the source device 100 reads "FLT_ready" periodically, for example every 2 milliseconds. When the source link training circuit reads "1" as the value of "FLT_ready", the source link training circuit selects a link rate and writes the identifier of the selected link rate to the "FRL_Rate" register.

[0079] Next, in step ST13, the control unit 203 determines whether or not the “FRL_Rate” register has been rewritten, that is, whether or not the link rate identifier has been written to the “FRL_Rate” register.

[0080] When the control unit 203 determines that a link rate identifier has been written to the “FRL_Rate” register, this write only occurs if the source device 100 supports link training with HDMI 2.1. Therefore, in step ST14, the control unit 203 displays a User Interface (UI) screen (not shown) on a display unit (not shown) to allow the user to select either an EDID for HDMI 2.1 (4K HFR) or an EDID for HDMI 2.1 (8K). Figure 11 shows an example of the UI screen. The user, for example, refers to this UI screen and selects either “4K HFR” or “8K”. The example shown shows the state where the EDID for HDMI 2.1 (4K HFR) has been selected.

[0081] Next, in step ST15, the control unit 203 determines whether to select "4K HFR" or "8K". If it determines that "4K HFR" is selected, the control unit 203 decides to have the source device 100 read the EDID for HDMI2.1 (4K HFR), and in step ST16, the EDID for HDMI2.1 (4K HFR) is retained in the EDID ROM 231.

[0082] In this case, the source device 100 already has the EDID for HDMI 2.1 (4K HFR) loaded (see explanation of step ST11). Therefore, at this point, it is not necessary to load the EDID for HDMI 2.1 (4K HFR) stored in the EDID ROM 231 into the source device 100, but it may be loaded again if desired.

[0083] Furthermore, when it is determined in step ST15 that "8K" is selected, the control unit 203 decides to have the source device 100 read the EDID for HDMI2.1 (8K), and in step ST17, it rewrites the EDID held in the EDID ROM 231 to the EDID for HDMI2.1 (8K). After this rewriting, the control unit 203 raises the HPD line to a high level, causing the source device 100 to read the EDID for HDMI2.1 (8K) set in the EDID ROM 231.

[0084] Furthermore, if step ST13 determines that no link rate identifier has been written to the “FRL_Rate” register, the control unit 203 proceeds to the processing in step ST18. As described above, since “FLT_ready” is read periodically, for example every 2 milliseconds, this determination is made, for example, after a value of 1 has been written to “FLT_ready” and at least the time interval between readings of “FLT_ready” has elapsed.

[0085] In step ST18, the control unit 203 determines whether “AKE_Init” has been written. The image data transmitted from the source device 100 to the sink device 200 via the HDMI cable 300 is encrypted by HDCP (High-bandwidth Digital Content Protection). HDMI 2.0 and HDMI 2.1 use HDCP 2.2.

[0086] Source device 100 performs an authentication process with sink device 200 via DDC to determine whether the sink device 200 has legitimate HDCP processing capabilities. In HDCP 2.2, the AKE (Authentication and Key Exchange) process is performed as the first step of the authentication protocol to exchange encryption keys. "AKE_Init" is an authentication activation message sent from source device (HDCP transmitter) 100 to sink device (HDCP receiver) 200 at the beginning of this AKE process.

[0087] When step ST18 determines that there is a “AKE_Init” write, the “AKE_Init” write occurs when the source device 100 uses HDCP2.2, as described above. Since HDMI2.0 uses HDCP2.2, the control unit 203 decides to have the source device 100 read the EDID for HDMI2.0.

[0088] Then, in step ST19, the control unit 203 rewrites the EDID held in the EDID ROM 231 to the EDID for HDMI 2.0. After this rewriting, the control unit 203 raises the HPD line to a high level, causing the source device 100 to read the EDID for HDMI 2.0 set in the EDID ROM 231.

[0089] Furthermore, if step ST18 determines that there is no “AKE_Init” written, the control unit 203 decides to have the source device 100 read the EDID for HDMI 1.4 or earlier. This decision is made after a predetermined amount of time, for example several hundred milliseconds or more, has elapsed since the value 1 was written to “FLT_ready”.

[0090] Then, in step ST20, the control unit 203 rewrites the EDID held in the EDID ROM 231 to an EDID for HDMI 1.4 or earlier. After this rewriting, the control unit 203 raises the HPD line to a high level, causing the source device 100 to read the EDID for HDMI 1.4 or earlier set in the EDID ROM 231.

[0091] In the EDID automatic switching control process shown in the flowchart of Figure 10, step ST11 involves setting the EDID for HDMI 2.1 (4K HFR) in the EDID ROM 231 and having the source device 100 read this EDID. However, it is also conceivable that step ST11 involves setting the EDID for HDMI 2.1 (8K) in the EDID ROM 231 and having the source device 100 read this EDID.

[0092] Furthermore, the above-described embodiment showed an example where the interface (Multimedia Link) was HDMI. This technology can be similarly applied to other interfaces that handle similar EDIDs. Other interfaces include, for example, the DP (Display Port) interface and MHL (Mobile High-definition Link). Also, although the above-described embodiment showed examples of HDMI 2.1, HDMI 2.0, and HDMI 1.4 and earlier, this technology is not limited to these examples and may be applied to future versions of HDMI. Similarly, although the above-described embodiment was explained using HDCP 2.2, this technology may be implemented using HDCP versions prior to HDCP 2.2 or HDCP versions after HDCP 2.2.

[0093] Furthermore, in the above embodiment, the EDID for HDMI 2.1 was initially stored in steps ST1 and ST11, but it is also possible to initially store the EDID for HDMI 1.4 or earlier, or the EDID for HDMI 2.0, and then switch to the EDID for HDMI 2.1 in response to the writing of "FRL_Rate".

[0094] Furthermore, while preferred embodiments of this disclosure have been described in detail with reference to the accompanying drawings, the technical scope of this disclosure is not limited to such examples. It is clear to any person with ordinary skill in the art of this disclosure that various modifications or alterations may be conceived within the scope of the technical idea set forth in the claims, and these too will naturally fall within the technical scope of this disclosure.

[0095] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that are obvious to those skilled in the art from the description herein, in addition to or instead of the effects described herein.

[0096] Furthermore, this technology can also be configured as follows: (1) A memory unit for storing first device information and second device information, A communications unit that communicates with external devices, The system includes a control unit that determines to have the external device read the second device information based on the reception of a rewrite signal to the first device information from the external device. Receiving device. (2) The memory unit further stores third device information, If the control unit does not receive the rewrite signal, it decides to have the third device information read by the external device. The receiving device described in (1) above. (3) The second device information corresponds to High-Definition Multimedia Interface (HDMI) version 2.1, and the third device information corresponds to HDMI version 2.0. The receiving device described in (2) above. (4) The second and third device information are each Extended Display Identification Data (EDID) which includes HDMI Forum Vendor Specific Data Block (HF-VSDB), which is information about the functions supported by the device. The receiving device described in (3) above. (5) The second device information is a 512-byte EDID which is a combination of the EDID for 4K High frame rate (HFR) and the EDID for 8K. The receiving device described in (3) above. (6) The memory unit further stores the fourth device information, The control unit decides to have the external device read the fourth device information if the external device does not correspond to the second device information and the third device information. A receiving device as described in any of (2) to (5) above. (7) If the control unit does not receive a predetermined signal from the external device, it determines that the external device does not correspond to the second device information and the third device information. The receiving device described in (6) above. (8) The predetermined signal is AKE_Init, which is the start signal for the authentication process with the external device. The receiving device described in (7) above. (9) The above-mentioned fourth device information is information corresponding to High-Definition Multimedia Interface (HDMI) version 1.4 or earlier. A receiving device as described in any of (6) to (8) above. (10) The fourth device information is Extended Display Identification Data (EDID) which includes a Vendor Specific Data Block (VSDB) that contains information about the functions supported by the device. The receiving device described in (9) above. (11) The rewrite signal is determined in accordance with the second device information. A receiving device as described in any of (1) to (10) above. (12) The rewrite signal is information corresponding to Max_FRL_Rate, which is information about the link rate supported by the device, as described in the second device information. The receiving device described in (11) above. (13) The rewrite signal is transmitted according to the value of FLT_ready, which is information indicating the readiness status of the link training process, as described in the first device information. A receiving device as described in any of (1) to (12) above. (14) The first device information is information included in the Status and Control Data Channel Structure (SCDCS). A receiving device as described in any of (1) to (13) above. (15) The first device information is FRL_Rate, which is information about the link rate selected by the external device. The receiving device described in (14) above. (16) The communication unit communicates with the external device via a digital interface cable. A receiving device as described in any of (1) to (15) above. (17) The digital interface cable is a High-Definition Multimedia Interface (HDMI) cable. The receiving device described in (16) above. (18) The receiving device is a display device. A receiving device as described in any of (1) to (17) above. (19) A memory unit for storing first device information and second device information, A control method for a receiving device equipped with a communication unit that communicates with external devices, Based on the reception of the rewrite signal for the first device information from the external device, it is decided to have the second device information read into the external device. A method for controlling a receiving device. (20) Consists of a transmitting device and a receiving device, The receiving device is, A memory unit for storing first device information and second device information, A communication unit that communicates with the aforementioned transmitting device, The system includes a control unit that determines to have the transmitting device read the second device information based on the reception of a rewrite signal for the first device information from the transmitting device. A transmission and reception system. [Explanation of Symbols]

[0097] 10. Transmit / Receive System 100... Source equipment (transmitter) 101...Receptacle 102...Data transmission unit (HDMI transmission unit) 103... Control Unit 121···HDMI Transmitter 122···IIC Master Block 200... Sink equipment (receiving device) 201···Receptacle 202...Data receiving unit (HDMI receiving unit) 203... Control Unit 221...HDMI Receiver 222...Memory section 231···EDID ROM 232...SCDC Register Section 233...HDCP Register Section 300...HDMI cable 301, 302... plugs

Claims

1. A memory unit that stores first device information, second device information, and third device information, and a communication unit that communicates with external devices via an interface that handles Extended Display Identification Data (EDID), The system includes a control unit that, based on the reception of a rewrite signal for the first device information from the external device, decides to have either the second device information or the third device information read into the external device. Receiving device.

2. The second device information corresponds to High-Definition Multimedia Interface (HDMI) version 2.1, and the third device information corresponds to HDMI version 2.

0. The receiving device according to claim 1.

3. The control unit, Based on the reception of a rewrite signal for the first device information from the external device, a user interface is displayed for selecting either the second device information or the third device information. Based on the selection in the user interface, it is decided to load either the second device information or the third device information into the external device. The receiving device according to claim 1.

4. The second device information corresponds to version 2.1 of High-Definition Multimedia Interface (HDMI), and the third device information corresponds to version 2.1 of HDMI and corresponds to video with a higher resolution than the second device information. The receiving device according to claim 3.

5. The first device information is information regarding the link rate selected by the external device. The receiving device according to claim 1.

6. The second device information mentioned above corresponds to version 2.1 of the High-Definition Multimedia Interface (HDMI). The receiving device according to claim 5.

7. The receiving device performs bidirectional communication with the external device. The receiving device according to claim 5.

8. The control unit is further configured to cause the external device to read the third device information if it does not receive the rewrite signal. The receiving device according to claim 1.

9. The third device information mentioned above corresponds to version 2.0 of High-Definition Multimedia Interface (HDMI). The receiving device according to claim 1.

10. The second and third device information are, respectively, Extended Display Identification Data (EDID) which includes a Vendor Specific Data Block (VSDB) containing information about the functions supported by the device. The receiving device according to claim 9.

11. The second device information is a 512-byte EDID formed by combining the EDID for 4K High Frame Rate (HFR) and the EDID for 8K. The receiving device according to claim 9.

12. The memory unit further stores the fourth device information, The control unit is further configured to cause the external device to read the fourth device information if the external device does not correspond to either the second device information or the third device information. The receiving device according to claim 8.

13. The control unit is further configured to determine that the external device does not correspond to either the second device information or the third device information if it does not receive a predetermined signal from the external device. The receiving device according to claim 12.

14. The predetermined signal is AKE_Init, which is the start signal for the authentication process with the external device. The receiving device according to claim 13.

15. The fourth device information is information corresponding to version 1.4 or earlier of the High-Definition Multimedia Interface (HDMI). The receiving device according to claim 12.

16. The fourth device information is Extended Display Identification Data (EDID), which includes a Vendor Specific Data Block (VSDB) that contains information about the functions supported by the device. The receiving device according to claim 15.

17. The rewrite signal is determined in accordance with the second device information. The receiving device according to claim 1.

18. The rewrite signal is information corresponding to Max_FRL_Rate, which is information about the link rate supported by the device, as described in the second device information. The receiving device according to claim 17.

19. The rewrite signal is transmitted according to the value of FLT_ready, which is information indicating the readiness status of link training, as described in the first device information. The receiving device according to claim 1.

20. The first device information mentioned above is information included in the Status and Control Data Channel Structure (SCDCS). The receiving device according to claim 1.

21. The first device information is FRL_Rate, which is information about the link rate selected by the external device. The receiving device according to claim 20.

22. The first device information is information including at least one flag indicating the current state of the receiving device. The receiving device according to claim 1.

23. The second device information is a 256-byte EDID for 4K High Frame Rate (HFR), and the third device information is a 256-byte EDID for 8K. The receiving device according to claim 4.

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