Chapter 6 Embedded Graphics Subsystems
6.2 INTEL 815E-BASED GRAPHICS SUBSYSTEM
The Intel 815E chipset integrates a graphics controller into its 82815 GMCH component (Figure
6-1).
Hub Link
I/F
Monitor
RGB
4 MB SDRAM
Display Cache
FSB
I/F
SDRAM
Controller
Direct AGP
Graphics
Controller
82815 GMCH
AGP Bus
Described in Chapter 3
Described in Chapter 4
Figure 6-1. 815E-Based Graphics, Block diagram
6.2.1 FUNCTIONAL DESCRIPTION
The graphics controller (Figure 6-2) integrated into the 82815 GMCH component includes 2D and
3D accelerator engines working with a deeply-pipelined pre-processor. The controller supports
perspective-correct texture mapping, bilinear and anisotropic Mip-mapping, Alpha blending,
Gouraud shading, and fogging.
The controller uses a “Direct AGP” interface that allows the Intel graphics controller to use a
portion of system memory for instructions, textures, and frame (display) buffering. Using a
process called Dynamic Video Memory Technology (DVMT), the controller dynamically
allocates display and texture memory amounts according to the needs of the application.
The controller also uses four megabytes of SDRAM (soldered down in small form factor models,
separate GPA/AIMM card in the slim desktop and configurable minitower models) as a display
cache especially suited for 3D operation. The additional Display Cache allows the graphics
controller to simultaneously render graphics to the Z-buffer (in the display cache) while
processing textures in a portion of system memory.
Compaq Deskpro and Evo Personal Computers
Featuring Intel Celeron and Pentium III Processors
Fifth Edition - March 2002
6-2
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