301467-005 Datasheet, PDF (251/426 Pages) Intel Corporation – Express Chipset

Functional Description
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device, but has no native panel fitting capabilities. The GMCH will, however, provide unscaled
mode where the display is centered on the panel.
12.7.2.2.2 LVDS Capabilities
The GMCH may use the multiplexed SDVO ports to drive a LVDS transmitter. Flat Panel is a
fixed resolution display. The GMCH supports panel fitting in the transmitter, receiver or an
external device, but has no native panel fitting capabilities. The GMCH will, however, provide
unscaled mode where the display is centered on the panel. The GMCH supports scaling in the
LVDS transmitter through the SDVO stall input pair.
12.7.2.2.3 TV-Out Capabilities
Although traditional TVs are not digital displays, the GMCH uses a digital display channel to
communicate with a TV-Out transmitter. For that reason, the GMCH considers a TV-Output to be
a digital display. GMCH supports NTSC and PAL standard definition formats. The GMCH
generates the proper timing for the external encoder. The external encoder is responsible for
generation of the proper format signal. Since the multiplexed SDVO interface is a
NTSC/PAL/SECAM display on the TV-Out port , it can be configured to be the boot device. It is
necessary to ensure that appropriate BIOS support is provided. If EasyLink is supported in the
GMCH, then this mechanism could be used to interrogate the display device.
The TV-Out interface on the GMCH is addressable as a master device. This allows an external
TV encoder device to drive a pixel clock signal on SDVO_TVClk[+/-] that the GMCH uses as a
reference frequency. The frequency of this clock is dependent on the output resolution required.
Flicker Filter and Overscan Compensation
The overscan compensation scaling and the flicker filter is done in the external TV encoder chip.
Care must be taken to allow for support of TV sets with high performance de-interlacers and
progressive scan displays connected to by way of a non-interlaced signal. Timing will be
generated with pixel granularity to allow more overscan ratios to be supported.
Direct YUV from Overlay
When source material is in the YUV format and is destined for a device that can take YUV format
data in, it is desired to send the data without converting it to RGB. This avoids the truncation
errors associated with multiple color conversion steps. The common situation will be that the
overlay source data is in the YUV format and will bypass the conversion to RBG as it is sent to
the TV port directly.
Sync Lock Support
Sync lock to the TV will be done using the external encoders PLL combined with the display
phase detector mechanism. The availability of this feature will be used to determine which
external encoder is in use.
Datasheet
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