Hardware Reference
In-Depth Information
Because the data is sent using 8b/10b encoding, only 8 bits of every 10 are actual data, resulting in a
maximum true video data throughput of 3.96Gbps. This enables a single-link DVI connection to easily
handle computer video resolutions as high as WUXGA (1920×1200) as well as 1080p HDTV
(1920×1080 with progressive scan).
If more bandwidth is necessary, the DVI standard supports a second TMDS link in the same cable and
connector. This uses three additional TMDS signal pairs (one for each color) and shares the same
clock and DDC signals as the primary link. This is called
dual-link DVI
, and it increases the
maximum raw bandwidth to 9.9Gbps and the true data bandwidth to 7.92Gpbs, which will handle
computer resolutions as high as WQUXGA (3840×2400). Normally only 30-inch or larger flat-panel
displays use resolutions high enough to require dual-link DVI. Even higher resolution displays can be
supported with dual DVI ports, each with a dual-link connection.
TMDS links include support for DDC, a low-speed, bidirectional standard for communication
between PCs and monitors, created by VESA. DDC defines the physical connection and signaling
method, whereas the communications and data protocol is defined under the VESA Extended Display
Identification Data (EDID) standard. DDC and EDID allow the graphics controller to identify the
capabilities of the display so the controller can automatically configure itself to match the display's
capabilities.
DVI uses Molex MicroCross connectors with several variations. The DVI standard was primarily
designed to support digital devices; however, for backward compatibility, it can also support analog
devices. The DVI-D (digital) connector supports only digital devices, whereas the DVI-I (integrated)
connector supports both digital and analog devices via the addition of extra pins.
Figure 12.6
and
Table 12.10
show the DVI-I (integrated) connector and pinout.
Figure 12.6. The DVI-I connector.
Table 12.10. DVI-I Connector Pinout
