Making HDTV in the car reliable and secure

December 15, 2011 // By Texas Instruments
Unique Ser/Des technology supports encrypted video and audio content with full duplex bi-directional control channel over a single wire interface.

High definition video, fast becoming the de facto standard within the home is now available in the automotive market. We expect the same viewing experience in the car that we have become accustomed to at home, and children want to watch their favorite Blu-ray discs on long journeys. Video distribution throughout an automobile is a considerable challenge to automotive infotainment system developers, especially at the signal bandwidths needed to support high defintion video content. Integrated circuit technologies that can handle the required data rates, reduce expensive cabling and connectors, and mitigate electromagnetic interference (EMI) problems are in great demand.

National Semiconductor (in the meantime acquired by Texas Instruments) recently released the industry's first Ser/Des chipset with on-chip high-bandwidth digital content protection (HDCP) for automotive infotainment systems. The FPD-Link III chipset enables secure distribution of encrypted video and audio content, such as Blu-ray movies up to 720p resolution, to create a home theater experience in the vehicle.  In addition it also supports a uniquely architected full duplex bi-directional control channel that enables real time touch screen applications. The chipset allows video and audio data, clock and control signals to be serialized and transmitted over a single differential wire.  This article describes the system benefits brought about by this technology, and other enhanced features that reduce EMI and total system cost. The simplified block diagram in figure 1 shows how multiple wires are replaced by a single differential pair.

Figure 1: FPD-Link III Simplified System Block Diagram

The third generation FPD-Link chipset described here consists of the DS90UH925Q serialiser and DS90UH926Q deserialiser. The DS90UH925Q converts video, digital I2S audio and control signals from the head unit processor (graphics processor, camera or Blu-ray/DVD player) into a serialized stream for distribution through the vehicle's cable harness. The DS90UH926Q converts the serialized information stream back into video, audio and control outputs to drive central information and rear passenger seat displays.

The consolidation of video data

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