Architectural Overview

The Intel® 440ZX AGPset includes the 82443ZX Host Bridge and the 82371EB PIIX4E for the I/O subsystem. The 82443ZX functions and capabilities include:
• Support for single Pentium II processor configurations
• 64-bit GTL+ based Host Bus Interface
• 32-bit Host address Support
• 64-bit Main Memory Interface with optimized support for SDRAM at 100 and 66/60 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
• Support for 66MHz-only or for 66MHz/100MHz host/DRAM bus frequency

Figure 1-1 shows a block diagram of a typical platform based on the Intel® 440ZX AGPset. The 82443ZX host bus interface supports a single Pentium II processor at a host/DRAM bus frequency of 66MHz. Also available is an 82443ZX which supports a host/DRAM bus at 66MHz/100MHz. The physical interface design is based on the GTL+ specification optimized for the desktop. The 82443ZX provides an optimized 64-bit DRAM interface. This interface is implemented as a 3.3Vonly 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 82443ZX provides interface to PCI operating at 33 MHz. This interface implementation is compliant with PCI Rev 2.1 Specification. The 82443ZX AGP interface implementation is based on Rev 1.0 of the AGP Specification. The AGP interface supports 133 MHz data transfer rates and can be used as a Secondary PCI interface operating at 66 MHz/3.3V supporting only a single PCI agent.

The 82443ZX 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
• 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