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Graphics Controller IC

The ATI RAGE 128 PRO graphics controller IC on the accelerated graphics card contains the logic for the video display. The ATI RAGE 128 PRO graphics controller includes the following features:

advanced 128-bit rendering engine
architecture optimized to support high-speed SDRAM video memory
display memory controller, built-in drawing coprocessor, video scaler, color space converter, clock generator, and true color palette video DAC (digital-to-analog converter)
video CLUT (color lookup table)
integrated support for digital flat panel monitors
hardware graphics acceleration with a 16-bit Z-buffer
accelerated QuickDraw 3D rendering up to six times that of software-only acceleration
true color palette DAC supporting pixel clock rates to 250 MHz
graphics and video line buffer for superior video scaling and playback quality
hardware cursor up to 64 x 64 x 2
DDC1 and DDC2B+ for plug-and-play monitor support
graphics control accessible through the QuickDraw, QuickDraw 3D, QuickDraw 3D RAVE, and QuickTime components APIs

A separate data bus handles data transfers between the ATI RAGE 128 PRO graphics controller and the display memory. The display memory data bus is 128 bits wide, and all data transfers consist of 128 bits at a time. The RAGE 128 PRO IC breaks each 128-bit data transfer into several pixels of the appropriate size for the current display mode--4, 8, 16, 24, or 32 bits per pixel.

The ATI RAGE 128 PRO graphics controller uses several clocks. Its transactions are synchronized with the AGP bus. Data transfers from the frame-buffer RAM are clocked by the MEM_CLK signal. Data transfers to the CLUT and the video output are clocked by the dot clock, which has a different rate for different display monitors.

The 2D graphics accelerator is a fixed-function accelerator for rectangle fill, line draw, polygon fill, panning/scrolling, bit masking, monochrome expansion, and scissoring.