DisplayPort

DisplayPort
DisplayPort connector
Type	Digital audio/video connector
Production history
Designer	VESA
Designed	May 2006
Produced	2008-present
Specifications
Hot pluggable	Yes
External	Yes
Electrical	+3.3 V
	Max. voltage	16.0 V
	Max. current	500  mA
Audio signal	Optional; 1-8 channels; 16, or 24-bit linear PCM; 48, 96, or 192 kHz sampling rate; uncompressed; max. 6.144 Mbit/s bit rate
Video signal	Optional, maximum resolution limited by available bandwidth
Data signal	Yes
	Bandwidth	1.62 or 2.7 GHz symbol rate; 1, 2, or 4 lanes (total 5.184 or 8.64 Gbit/s data rate) plus 1 Mbit/s for the auxiliary channel.
	Protocol	mini-packet
Cable	Maximum length 15 meters for video transmission (resolution at least 1920×1080p60 at 24 bpp), 3 meters for full bandwidth transmission, made of materials of either copper or optical fibre.
Pins	20 pins for external connectors on desktops, notebooks, graphics cards, monitors, etc. and 30/20 pins for internal connections between graphics engines and built-in flat panels.
Pin out
External connector (source-side) on PCB
Pin 1	ML_Lane 0 (p)	Lane 0 (positive)
Pin 2	GND	Ground
Pin 3	ML_Lane 0 (n)	Lane 0 (negative)
Pin 4	ML_Lane 1 (p)	Lane 1 (positive)
Pin 5	GND	Ground
Pin 6	ML_Lane 1 (n)	Lane 1 (negative)
Pin 7	ML_Lane 2 (p)	Lane 2 (positive)
Pin 8	GND	Ground
Pin 9	ML_Lane 2 (n)	Lane 2 (negative)
Pin 10	ML_Lane 3 (p)	Lane 3 (positive)
Pin 11	GND	Ground
Pin 12	ML_Lane 3 (n)	Lane 3 (negative)
Pin 13	CONFIG1	connected to Ground1)
Pin 14	CONFIG2	connected to Ground1)
Pin 15	AUX CH (p)	Auxiliary Channel (positive)
Pin 16	GND	Ground
Pin 17	AUX CH (n)	Auxiliary Channel (negative)
Pin 18	Hot Plug	Hot Plug Detect
Pin 19	Return	Return for Power
Pin 20	DP_PWR	Power for connector
1) Pins 13 and 14 may either be directly connected to ground or connected to ground through a pulldown device. 2) This is the pinout for source-side connector, the sink-side connector pinout will have lanes 0-3 reversed in order; i.e., lane 3 will be on pin 1 and 3 while lane 0 will be on pin 10 and 12.

DisplayPort is a digital display interface standard put forth by the Video Electronics Standards Association (VESA) since 2006. It defines a new royalty-free, digital audio/video interconnect, intended to be used primarily between a computer and its display monitor, or a computer and a home-theater system.

The first version was approved in May 2006, while the current version (1.1a) was approved on January 11, 2008.

Overview

The DisplayPort connector supports 1, 2, or 4 data pairs in a Main Link that also carries clock and optional audio signals, each with a symbol rate of 1.62 or 2.7 Gbit/s. The video signal path supports 6 to 16 bits per color channel. A bi-directional auxiliary channel (at a constant 1 Mbit/s) carries management and device control data for the Main Link using VESA EDID and VESA MCCS standards. The video signal is not compatible with DVI or HDMI, but a DisplayPort connector can pass these signals through. While DVI and HDMI require separate clock signals, DisplayPort embeds the clock in the data signal. The data transmission protocol in DisplayPort is based on micro packets and is extensible for future feature additions, whereas DVI/HDMI transmission protocol is a Serial Data Stream at a multiple of 10 of the pixel clock rate. Finally, unlike the separate DVI/HDMI and LVDS standards, DisplayPort supports both external (box-to-box) and internal (laptop LCD panel) display connections.

DisplayPort currently supports a maximum of 8.64 Gbit/s data rate over a 2 meter cable.^[1]

DisplayPort is a competitor to the HDMI connector (with HDCP copy-protection), the de facto standard digital connection for high-definition consumer electronics devices. Another competitor was Unified Display Interface,^[2] a low cost compatible alternative to HDMI and DVI. However, the main supporter of UDI, Intel Corporation, has stopped the development of the technology and now supports DisplayPort.

Newly featured in version 1.1 is support for fiber optic cables as an alternative to copper, allowing a much longer reach between source and display without signal degradation,^[3] as well as DPCP (see below).

Embedded DisplayPort (eDP) 1.1a standard was adopted in February 2008. It aims to define a standardized display panel interface for internal connections, i.e. graphic cards to notebook display panels.^[4]

A preview of DisplayPort 1.2 was given at WinHEC 2008 and CES 2009. One planned improvement of this version is the doubling of the bandwidth, which would allow for increased resolutions, higher refresh rates, and deeper color depth. Other improvements include multiple independent video streams (daisy-chain connection with multiple monitors), support for stereoscopic 3D, increased AUX channel bandwidth, and addition of Apple Inc.'s Mini DisplayPort connector, which is much smaller and more appropriate for laptop computers and other small devices.^[5] The DisplayPort 1.2 standard is expected to be adopted in 2009.^[6][7]

DRM protection

DisplayPort includes optional DPCP (DisplayPort Content Protection) copy-protection from Philips, which uses 128-bit AES encryption, with modern cryptography ciphers. It also features full authentication and session key establishment (each encryption session is independent). There is an independent revocation system. This portion of the standard is licensed separately. It also adds support for verifying the proximity of the receiver and transmitter, a technique intended to ensure users are not bypassing content protection system to send data out to distant, unauthorized users.

Version 1.1 added support for HDCP.

Advantages over DVI

1. Slimmer cables and a much smaller connector that doesn't require thumbscrews. Connector pins don't run the risk of bending if improperly handled.
2. In low-light conditions or awkward under-desk connections, the DisplayPort connector is easier to connect when guided only by touch.
3. Based on micro-packet protocol.
   • Allows easy expansion of the standard
   • Allows multiple video streams over single physical connection (in a future version)
4. Designed to support internal chip-to-chip communication
   • Can drive display panels directly, eliminating scaling and control circuits and allowing for cheaper and slimmer displays
   • Aimed to replace internal LVDS links in notebook panels with a unified link interface
   • Compatible with low-voltage signalling used with 45 nm CMOS fabrication
5. Supports both RGB and YCbCr encoding formats
6. Auxiliary channel can be used for low bandwidth data such as touch-panel data.
7. Fewer lanes with embedded clock reduce RFI.

Relationship with HDMI

The DisplayPort website states that DisplayPort is expected to complement HDMI, a popular compact audio/video interface.^[8] Most of the DisplayPort supporters are computer companies such as Apple, G7, Dell, HP or Lenovo some of which have released several computer monitors that support DisplayPort and some also with HDMI.^[9][10] Apple's current computers do not support audio over DisplayPort.

DisplayPort is currently royalty free, while the HDMI royalty is 4 cents per device and has an annual fee of $10,000 for high volume manufacturers.^[11]

However, HDMI has certain features that DisplayPort lacks such as support for the xvYCC color space, Consumer Electronics Control (CEC) signals, and electrical compatibility with DVI.^[12][13]

In the interest of interoperability, the display port connection is capable of supporting HDMI/DVI signals.^[8] DisplayPort has issued guidelines on the construction of active DisplayPort-to-VGA, DisplayPort-to-SVIDEO/Composite/Other, DisplayPort-to-Dual-Link-DVI/HDMI, and Dual-Link-DVI/HDMI-to-DisplayPort Converters. In addition to active converters, the same guideline document also describes a way for devices supporting both DisplayPort and DVI 1.0 or HDMI to use a single DisplayPort connector for both, using a relatively simple adapter that adjusts for the lower voltages required by the DisplayPort connector. A Notable limitation is that this is limited to Single Link DVI/HDMI, and that an active Converter is needed for Dual-Link communication.

Technical specifications

• 5.184 or 8.64 Gbit/s forward link channel supports high resolution displays with a single cable.^†
• 8b/10b data transmission (up to 2.7 GHz symbol rate, up to four lanes).
• Reduced bandwidth transmission for 15 meter cable (at least 1920x1080p60, 24 bpp).
• Full bandwidth transmission for 2 meter cable.
• Supports color depth of 6, 8, 10, 12 and 16 bits per color component.
• Supports YCbCr color space (ITU-R BT.601-5 and BT.709-4), 4:2:2 chroma subsampling
• Optional Dual-Mode support generates DVI/HDMI signal with a simple line-level conversion dongle.^[14]
• 128-bit AES DisplayPort Content Protection (DPCP) support, and support for 40-bit High-bandwidth Digital Content Protection (HDCP) from version 1.1 onwards.
• Supports internal and external connections so that one standard can be used by computer makers reducing costs.^[15]
• Open and extensible standard to help with broad adoption.

General and technical overviews can be downloaded at DisplayPort.org.

† Sample data rates required by various display resolutions using common vertical blanking methods, Gbit/s:

Note: bpp is the number of bits for each pixel; for RGB and YCbCr 4:4:4, the bpp value is three times the bits per color component (bpc); for YCbCr 4:2:2 subsampling, the bpp value is twice the bpc value.

Products

Before being acquired by AMD, one of the supporters, ATI reported that they were expecting DisplayPort products in early 2007. On 25 July 2007, at AMD's Technology Analyst Day 2007, AMD renewed their commitment to supporting DisplayPort with the 780G chipset and RV670 graphics cards with external DisplayPort transmitter. The company also committed to implement the transmitter on chip level for its RV635 and RV620 graphics products in its Financial Analyst Day 2007 held on 13 December 2007, providing support without external transmitters. These products obtained certification from VESA on 19 March 2008.^[16]

In 2009, some graphic card manufacturers started including DisplayPort on their graphic cards based on ATI/AMD RV870 Graphic chip.

The newest line of AMD/ATI graphics cards, the Radeon 5800 series, are the first line to incorporate DisplayPort connector on a GPU-wide level, along side 2x DualLink DVI connectors, and a single HDMI connector. It will allow up to 3 displays on a single graphics card. A second version is also available with 6 Mini DisplayPorts allowing up to 6 displays on the same card. ^[17]

Genesis Microchip also announced DisplayPort products to be available in 2007,^[18] as did Samsung.^[19] A concept monitor by Dell implementing DisplayPort was demonstrated early May 2007.^[20]

The Dell 3008WFP 30-inch (76 cm), released in January 2008 was the first monitor to support DisplayPort.^[21][22] The Dell 2408WFP 24-inch (61 cm) followed in April 2008.^[23] Apple's LED Cinema Display, and HP's LP2275w, LP2475w, and LP2480zx monitors also support DisplayPort.

On 14 October 2008, Apple introduced several products featuring a Mini DisplayPort^[24] as their sole video connector. As of 20 October 2009, all current Mac models available directly from Apple support output through a Mini DisplayPort. The current iMac, MacBook and MacBook Pro models use Mini DisplayPort as their sole video output port while the Mac Mini and Mac Pro models have both a Mini DisplayPort and either a DVI port (Mac Pro) or Mini DVI port (Mac Mini). The 27-inch iMac model also allows the Mini DisplayPort to act as an input, turning the iMac into a standalone display.^[25]

Dell also supplies current business class products such as the Latitude and Precision laptops and Optiplex desktops with DisplayPort connectors - sometimes superseding DVI connectors.

In October of 2009 Atlona Technologies release the world's first converter capable of converting from DVI video formats to Mini DisplayPort, the AT-DP200. ^[26]

Supporters

The following companies have announced their intention, at one point or another, to implement or support DisplayPort:

• AMD/ATI
• Atlona Technologies ^[27]
• Analogix^[28]
• Apple
• ASRock^[29]
• Circuit Assembly
• DataPro
• Dell
• Eizo
• Genesis Microchip
• Gigabyte Technology
• Hall Research Technologies
• Hewlett-Packard
• Hosiden Corporation
• Intel
• Integrated Device Technology
• Japan Aviation Electronics
• Lenovo
• Luxtera
• Matrox Graphics
• Molex
• Micro-Star International^[30]
• Mstar
• NVIDIA
• NXP Semiconductors
• Palit Microsystems Ltd.
• Parade Technologies
• Pioneer Corporation
• Philips
• Quantum Data
• S3 Graphics
• Samsung
• Sparkle Computer
• Texas Instruments
• Tyco Electronics
• Unigraf

See also

• List of computer standards

References

External links

• DisplayPort homepage
• Bridging the new DisplayPort standard