301467-005 Datasheet, PDF (249/426 Pages) Intel Corporation – Express Chipset

Functional Description
R
12.7.1 Analog Display Port Characteristics
The analog display port provides a RGB signal output along with a HSYNC and VSYNC signal.
There is an associated DDC signal pair that is implemented using GPIO pins dedicated to the
analog port. The intended target device is for a CRT based monitor with a VGA connector.
Display devices (such as LCD panels) with analog inputs may work satisfactory but no
functionality has been added to the signals to enhance that capability.
Table 12-7. Analog Port Characteristics
Signal
RGB
HSYNC
VSYNC
DDC
Port Characteristic
Voltage Range
Monitor Sense
Analog Copy Protection
Sync on Green
Voltage
Enable/Disable
Polarity adjust
Composite Sync Support
Special Flat Panel Sync
Stereo Sync
Voltage
Control
Support
0.7 V p-p only
Analog Compare
No
No
2.5 V
Port control
VGA or port control
No
No
No
Externally buffered to 5V
Through GPIO interface
12.7.1.1
12.7.1.2
12.7.1.3
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. The GMCH’s integrated 400 MHz RAMDAC supports resolutions up to 2048 x 1536 @
85Hz. Three 8-bit DACs provide the RED, GREEN, and BLUE 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 power up disabled in the high state. No composite sync or special flat panel sync
support is 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.
Datasheet
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