AC82G41SLGQ3 Datasheet, PDF (536/604 Pages) Intel Corporation – Intel® 4 Series Chipset Family

Functional Description
13.5.1.1
13.5.1.2
13.5.1.3
13.5.1.4
13.5.2
13.5.2.1
Integrated RAMDAC
The display function contains a RAM-based Digital-to-Analog Converter (RAMDAC) that
transforms the digital data from the graphics and video subsystems to analog data for
the CRT monitor. GMCH’s integrated 350 MHz RAMDAC supports resolutions up to
2048 x 1536 @ 75 Hz. Three 8-bit DACs provide the R, G, and B signals to the monitor.
Sync Signals
HSYNC and VSYNC signals are digital and conform to TTL signal levels at the connector.
Since these levels cannot be generated internal to the device, external level shifting
buffers are required. These signals can be polarity adjusted and individually disabled in
one of the two possible states. The sync signals should power up disabled in the high
state. No composite sync or special flat panel sync support will be included.
VESA/VGA Mode
VESA/VGA mode provides compatibility for pre-existing software that set the display
mode using the VGA CRTC registers. Timings are generated based on the VGA register
values and the timing generator registers are not used.
DDC (Display Data Channel)
DDC is a standard defined by VESA. Its purpose is to allow communication between the
host system and display. Both configuration and control information can be exchanged
allowing plug- and-play systems to be realized. Support for DDC 1 and DDC 2 is
implemented. The GMCH uses the CRT_DDC_CLK and CRT_DDC_DATA signals to
communicate with the analog monitor. The GMCH will generate these signals at 2.5 V.
External pull-up resistors and level shifting circuitry should be implemented on the
board.
The GMCH implements a hardware GMBus controller that can be used to control these
signals allowing for transactions speeds up to 400 kHz.
Digital Display Interface
The GMCH can drive HDMI, DVI, and Display Port natively. The digital ports B and/or C
can be configured to drive HDMI, DVI, and Display Port. The digital ports are
multiplexed on to the PEG interface.
High Definition Multimedia Interface (Intel^® 82G45, 82G43, 82G41,
82B43 GMCH Only)
The High-Definition Multimedia Interface (HDMI) is provided for transmitting
uncompressed digital audio and video signals from DVD players, set-top boxes, and
other audiovisual sources to television sets, projectors, and other video displays. It can
carry high-quality multi-channel audio data and all standard and high-definition
consumer electronics video formats.
HDMI display interface connecting the GMCH and display devices uses transition
minimized differential signaling (TMDS) to carry audiovisual information through the
same HDMI cable.
HDMI includes three separate communications channels: TMDS, DDC, and the optional
CEC (consumer electronics control). As shown in Figure 11, the HDMI cable carries four
differential pairs that make up the TMDS data and clock channels. These channels are
used to carry video, audio and auxiliary data. In addition, HDMI carries a VESA Display
data channel (DDC). The DDC channel is used by an HDMI Source to determine the
capabilities and characteristics of the Sink.
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Datasheet