82815 GMCH
R
Datasheet
151
4.8.11.
Display
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 monitor. The GMCH’s
integrated 230 MHz RAMDAC provides resolution support up to 1600x1200. Circuitry is incorporated
to limit the switching noise generated by the DACs. Three 8-bit DACs provide the R, G, and B signals to
the monitor. Sync signals are properly delayed to match any delays from the D-to-A conversion.
Associated with each DAC is a 256 pallet of colors. The RAMDAC can be operated in either direct or
indexed color mode. In Direct color mode, pixel depths of 15, 16, or 24 bits can be realized. Non-
interlaced mode is supported. Gamma correction can be applied to the display output.
The GMCH supports a wide range of resolutions, color depths, and refresh rates via a programmable dot
clock that has a maximum frequency of 230 MHz.
Table 19. Partial List of Display Modes Supported
Bits Per Pixel (frequency in Hz)
Resolution
8-bit Indexed
16-bit
24-bit
320x200
70
70
70
320x240
70
70
70
352x480
70
70
70
352x576
70
70
70
400x300
70
70
70
512x384
70
70
70
640x400
70
70
70
640x480
60,70,72,75,85
60,70,72,75,85
60,70,72,75,85
720x480
75,85
75,85
75,85
720x576
60,75,85
60,75,85
60,75,85
800x600
60,70,72,75,85
60,70,72,75,85
60,70,72,75,85
1024x768
60, 70,72,75,85
60, 70,72,75,85
60, 70,72,75,85
1152x864
60,70,72,75,85
60,70,72,75,85
60,70,72,75,85
1280x720
60,75,85
60,75,85
60,75,85
1280x960
60,75,85
60,75,85
60,75,85
1280x1024
60,70,72,75,85
60,70,72,75,85
60,70,75,85
1600x900
60,75,85
60,75,85
1600x1200
60,70,72,75