Vizio GV42L HDTV, L42HDTV10A Tmds Digital Core, Active port detection, Hdcp Decryption

1. TMDS Digital Core

The core performs 10-to-8-bit TMDS decoding on the audio and video received from the three TMDS differential data lines along with a TMDS differential clock. The TMDS core supports link clock rates to 165MHZ, including CE modes to 720P/1080I/1080P.

2. Active port detection

The Pane Link core detects an active TMDS clock and actively toggling DE signal. These states are accessible in register bits, useful for monitoring the status of the HDMI input or for automatically powering down the receiver. The 5V supply from the HDMI connector is used as a cable detect indicator. The MT8293 can monitor the presence of this+5V supply and, if and when necessary, provide a fast audio mute without pops when it senses the HDMI cable pulled. The microcontroller can also poll registers in the MT8293 to check whether an HDMI cable is connected.

3.HDCP Decryption

The MT8293 external EEPROM for encrypt HDCP keys. HDCP decryption contains all necessary logic to decrypt the incoming audio and video data. The decryption process is entirely controlled by the host microprocessor through a set sequence of register reads and wires through the DDC channel. Pre-programmed HDCP keys and key Selection Vector are used in the decryption process. A resulting calculated to an XOR mask during each clock cycle to decrypt the audio/video data in sync with the host.

4.Video Data Conversion and Video Output

The MT8293 can output video in many different formats as shown in the following figure.

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