Architectural Overview

The Intel® 440GX AGPset includes the 82443GX Host Bridge and the 82371EB PIIX4E for the I/O subsystem. The 82443GX functions and capabilities include:

• Support for single and dual Pentium® II processor and Pentium® II Xeon™ processor configurations

• 64-bit GTL+ and AGTL+ based System (Host) Bus Interface

• 32-bit Host address Support

• 64-bit Main Memory Interface with optimized support for SDRAM at 100 MHz

• 32-bit Primary PCI Bus Interface (PCI) with integrated PCI arbiter

• AGP Interface (AGP) with 133 MHz data transfer capability configurable as a Secondary PCI Bus

• Extensive Data Buffering between all interfaces for high throughput and concurrent operations

• “Deep Green” Desktop power management support

Figure 1-1 shows a block diagram of a typical platform based on the Intel® 440GX AGPset. The 82443GX host bus interface supports up to two Pentium II processors or two Pentium II Xeon™ processors at 100 MHz bus frequency. The physical interface design is based on the GTL+ specification optimized for the desktop. The 82443GX provides an optimized 64-bit DRAM interface. This interface is implemented as a 3.3V-only interface that supports only 3V DRAM technology. Two copies of the MA, and CS# signals drive a maximum of two DIMMs each; providing unbuffered high performance at 100 MHz. The 82443GX provides interface to PCI operating at 33 MHz. This interface implementation is compliant with PCI Rev 2.1 Specification. The 82443GX AGP interface implementation is based on Rev 1.0 of the AGP Specification. The AGP interface supports 133 MHz data transfer rates.

The 82443GX is designed to support the PIIX4E I/O bridge. PIIX4E is a highly integrated

multifunctional component supporting the following functions and capabilities:

• PCI Rev 2.1 compliant PCI-ISA Bridge with support for both 3.3V and 5V 33 MHz PCI operations

• Deep Green Desktop Power Management Support

• Enhanced DMA controller and Interrupt Controller and Timer functions

• Integrated IDE controller with Ultra DMA/33 support

• USB host interface with support for 2 USB ports

• System Management Bus (SMB) with support for DIMM Serial PD

• Support for an external I/O APIC component