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VESA DisplayPort Standard v1.0

by August 20, 2005

DisplayPort is an extensible industry standard intended to consolidate both external (box-to-box) and internal (LCD panel) display connections. The Promoter Group (made up of ATI, Dell, Genesis Microchip, HP, Molex, NVIDIA, Philips, Samsung and Tyco) developed the initial specification and handed it off to VESA on August 17, 2005. VESA will publish and maintain the DisplayPort specification as an industry standard. Audio and content protection are optional features and Philips is developing the Content Protection (CP) system, which will be licensed separately. The electrical interface is similar to the PCI Express physical layer and it provides a small, user-friendly external connector. DisplayPort can accommodate 4 connectors on a PCI card and has support for cables up to 15 meters in length.

High Level Objectives

DisplayPort is designed to be an open digital display interconnect standard, agnostic to application/topology/data-type. It will support "box-to-box" (PC-to-monitor or PC-to-HDTV) connections as well as "board-to-board/chip-to-chip" (PC graphics processor to notebook panel timing controller) connections. The spec will support Plug-and-Play with robust interoperability. It is designed to be very cost competitive with existing digital display interconnects. The specification is scalable and extensible in terms of pixel depth, resolution, data types, and number of streams. DisplayPort has a layered, modular architecture and can support various link media types (i.e., PHY layer) with no change in the Link Layer

How DisplayPort Differs from DVI

DVI is not available with mainstream integrated graphics solutions in PCs. What they mean by this is that a digital display interface needs to be compatible with sub-65nm process technology in order to have broad availability in PCs. The DVI 1.0 specification is "frozen" and can't really be updated, therefore its dot clock and color depth are fixed. It's also somewhat difficult to reduce electronics in a monitor design with DVI. As a result manufacturers are stuck with the rather large DVI connector. In addition, displays with greater than UXGA resolution require dual channel DVI implementation.

How DisplayPort Differs from HDMI

HDMI is a great consumer electronics interface, but VESA does not feel it is the best solution for PCs as a monitor interface. A somewhat limited performance is available in terms of resolution and color depth for PC monitors (see comparison chart for exactly how this might impact future displays). Due, partially, to somewhat excessive licensing fees, HDMI is designed to be a premium A/V interface, rather than as a broadly available general purpose display interface. The HDMI specification is not geared to unifying internal and external display connections; its primary focus is consumer electronics.

The Make-up of DisplayPort

The Main Link is high bandwidth, low latency, and unidirectional. It supports isochronous stream transport and has one uncompressed video stream with associated audio (ver. 1.0) and is seamlessly extensible for supporting multiple video streams. The Auxiliary Channel is characterized by consistent bandwidth, low latency, and is bi-directional. It provides Main Link management and device control (EDID, MCCS).

displayportmakeup.gif

DPCP (DisplayPort Content Protection)

DPCP provides AES type high speed 128-bit content encryption with secure modern ciphers. It also features full authentication and session key establishment (each encryption session is independent). There is an independent revocation system that can defeat "cloning" attacks and can also work within a standard SRM-based system. DPCP has standard license features including robustness rules and compliance rules.

DisplayPort Compared Against LVDS, DVI and HDMI


DisplayPortDVIHDMIcompared_th.gif

Information provided by VESA. Please visit them at http://www.vesa.org

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About the author:

Clint Deboer was terminated from Audioholics for misconduct on April 4th, 2014. He no longer represents Audioholics in any fashion.

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