System Bus Interface, Dram Interface | Intel 440GX specification

Introduction

Figure 1-1shows a block diagram of a typical platform based on the Intel® 440GX AGPset. The 82443GX system bus interface supports up to two Intel® Pentium® II processors at the maximum bus frequency of 100 MHz. The physical interface design is based on the GTL+ specification and is compatible with the Intel® 440GX AGPset solution. The 82443GX provides an optimized 72-bit DRAM interface (64-bit Data plus ECC). This interface supports 3.3V DRAM technologies.

The 82443GX is designed to support the PIIX4E I/O bridge. The PIIX4E is a highly integrated multifunctional component that supports the following functions and capabilities:

•PCI Rev 2.1 compliant PCI-to-ISA Bridge with support for 33 MHz PCI operations

•ACPI Desktop Power Management Support

•Enhanced DMA controller and standard 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 Presence Detect

•Support for an external I/O APIC component

1.3.2.1System Bus Interface

The Intel® Pentium® II processor supports a second level cache size of 512 KB with ECC. All cache control logic is provided on the processor. The 82443GX supports a maximum of 32 bit address or 4 GB memory address space from the processor perspective. The 82443GX provides bus control signals and address paths for transfers between the processors bus, PCI bus, Accelerated Graphics Port and main memory. The 82443GX supports a 4-deep in-order queue (i.e., it provides support for pipelining of up to 4 outstanding transaction requests on the system bus).

For system bus-to-PCI transfers, the addresses are either translated or directly forwarded on the PCI bus, depending on the PCI address space being accessed. If the access is to a PCI configuration space, the processor I/O cycle is mapped to a PCI configuration space cycle. If the access is to a PCI I/O or memory space, the processor address is passed without modification to the PCI bus. Certain memory address range (later referred in a document as a Graphics Aperture) are dedicated for a graphics memory address space. If this space or portion of it is mapped to main DRAM, then the address will be translated via the AGP address remapping mechanism and the request forwarded to the DRAM subsystem. A portion of the graphics aperture can be mapped on AGP and corresponding system bus cycles that hit that range are forwarded to AGP without any translation. Other system bus cycles forwarded to AGP are defined by the AGP address map.

1.3.2.2DRAM Interface

The 82443GX integrates a main memory controller that supports a 64/72-bit DRAM interface which operates at 100 MHz. The integrated DRAM controller features: supports up to 4 double- sided DIMMs, 8M to 256M using 16Mbit technology, 1 GB using 64Mbit technology, and 2 GB using 128M or 256M technology, two copies of MAxx are provided for optimized timing, and ECC with hardware scrubbing.

1.3.2.3Accelerated Graphics Port Interface

The 82443GX supports an AGP interface. The AGP interface can reach a maximum theoretical ~532 Mbytes/sec transfer rate.

Intel®440GX AGPset Design Guide

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440GX specifications

The Intel 440GX chipset was launched in 1997 as part of Intel's series of chipsets known as the 440 family, and it served as a critical component for various Pentium II and Pentium III-based motherboard architectures. Specifically designed for the second generation of Intel’s processors, the 440GX delivered enhanced performance and supported a range of important technologies that defined PC architectures of its time.

One of the main features of the Intel 440GX was its support for a 100 MHz front-side bus (FSB), which significantly improved data transfer rates between the CPU and the memory subsystem. This advancement allowed the 440GX to accommodate both the original Pentium II processors as well as the later Pentium III chips, providing compatibility and flexibility for system builders and consumers alike.

The 440GX chipset included an integrated AGP (Accelerated Graphics Port) controller, which supported AGP 2x speeds. This enabled high-performance graphics cards to be utilized effectively, delivering many enhanced graphics capabilities for gaming and multimedia applications. The AGP interface was crucial at the time as it offered a dedicated pathway for graphics data, increasing bandwidth compared to traditional PCI slots.

In terms of memory support, the 440GX could address up to 512 MB of SDRAM, allowing systems built with this chipset to run comfortably with sufficient memory for the era’s demanding applications. The memory controller was capable of supporting both single and double-sided DIMMs, which provided versatility in memory configuration for system builders.

Another notable feature of the Intel 440GX was its support for multi-processor configurations through its Dual Processors support feature. This allowed enterprise and workstation computers to leverage the performance advantages of multiple CPUs, making the chipset suitable for business and professional environments where multitasking and high-performance computing were essential.

On the connectivity front, the chipset supported up to six PCI slots, enhancing peripheral device integration and expansion capabilities. It also included integrated IDE controllers, facilitating connections for hard drives and CD-ROM devices.

Overall, the Intel 440GX chipset represented a balanced combination of performance, flexibility, and technology advancements for its time. Its introduction helped establish a foundation for subsequent advancements in PC technology and set the stage for more powerful computing systems in the years to come.

Intel 440GX manual System Bus Interface, Dram Interface, Accelerated Graphics Port Interface

Models: 440GX