Hardware Reference
In-Depth Information
The adapter cable shown in
Figure 12.8
is not designed to work with graphics cards and
drivers that do not support HDTV resolutions and timings. You may need to upgrade your
graphics card driver before using an HDMI-DVI cable. Although some set-top boxes include
DVI ports, this type of adapter cable is only intended for PC-HDTV connections.
In addition to supporting specific versions of the HDMI standard, HDMI cables are available in two
speeds: Category 1 (Standard) and Category 2 (High Speed). Category 1 (Standard) cables support
up to 720p/1080i resolutions (speeds up to 75Mhz or 2.26Gbps), while Category 2 (High-Speed)
cables support 1080p resolutions, running at speeds up to 340Mhz or 10.2Gbps.
Starting in late 2006, some vendors began to release PCIe cards including HDMI ports. Some
provide HDMI input and output for use with HDV camcorders, whereas others using ATI or NVIDIA
chipsets are graphics cards that also include HDMI output. Although HDMI is a royalty-based
interface, requiring an annual license fee of $10,000 plus a payment of 4 cents per device, and the
newer DisplayPort interface is royalty-free, HDMI continues to be used on a wider range of current
video cards and systems with integrated graphics than the obsolescent DVI or emerging DisplayPort
standards. Some recent cards, such as the one shown in
Figure 12.1
, use the mini-HDMI (HDMI Type
C) connector to save space on the card bracket.
For more information about HDMI, see the HDMI Forum website at
www.hdmiforum.org
.
DisplayPort
DisplayPort is the latest digital display interface standard. It is designed to replace VGA, DVI, and
HDMI for use in PCs and to coexist with HDMI in consumer electronics devices. Dell originated the
design in 2003 and then turned it over to VESA in August 2005. In May 2006, VESA published it as
an open industry standard. Consequently, DisplayPort is a royalty-free interface and does not incur
the licensing fees of HDMI or the implementation patent fees of DVI. Also, DisplayPort is designed
both as an internal and an external interface, meaning it can replace the FPD-Link (Flat Panel
Display-Link) interface used internally in most laptops as well as providing connections to external
displays. In short, DisplayPort is designed to be the ultimate universal display interface for PCs now
and in the future. Previous digital display interfaces such as DVI and HDMI used TMDS, which
requires extra logic on both the source and display ends, logic that must usually be licensed from
Silicon Image. DisplayPort instead uses a packetized (network-like) interface that can easily be
implemented in chipsets without the extra cost logic required for DVI or HDMI. DisplayPort is kind
of like a high-speed Ethernet for video, and the network-like design allows for features such as
multiple video streams over a single connection, which means you can connect multiple displays to a
single port.
Because it is a license-free, royalty-free design, DisplayPort has seen rapid adoption throughout the
industry. In fact, all new chipsets and GPUs since 2008 from Intel, NVIDIA, and AMD/ATI already
have integrated DisplayPort support. In 2008, major manufacturers including Dell, HP/Compaq,
Lenovo, and Apple introduced products with DisplayPort and endorsed DisplayPort as the successor
to DVI and HDMI for most digital display connections. Despite this endorsement, the introduction of
DisplayPort-enabled products has proceeded slowly. However, DisplayPort is currently available on
an increasing number of laptops, 23-inch or larger LCD and backlit LED displays, computers, and
graphics cards for desktop and technical workstation use.
On the technical side, DisplayPort is a high-speed serial interface with up to four main data lanes
