Intel 815E-Based Graphics Subsystem; Functional Description - Compaq Evo D500 Technical Reference Manual

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).
4 MB SDRAM
Display Cache
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.
6-2 Compaq Deskpro and Evo Personal Computers
Featuring Intel Celeron and Pentium III Processors
AGP Bus
Direct AGP
Graphics
RGB
Controller
Monitor
Fifth Edition - March 2002
82815 GMCH
FSB
I/F
SDRAM
Controller
Hub Link
I/F