845GL datasheet(15/193 Pages) INTEL

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Intel® 82845G/82845GL/82845GV GMCH Datasheet

Introduction

1.3

Intel® 845G Chipset System Overview

Figure 1-1 shows an example block diagram of an 845G chipset-based platform. The 845G chipset

is designed for use in a desktop system based on an Intel® Pentium® 4 processor in a 478-pin

package. The 845G chipset supports the Pentium 4 processor with 256-KB L2 cache and the

Pentium 4 processor with 512-KB L2 cache on 0.13 micron process. The processor interface

supports the Pentium 4 processor subset of the Extended Mode of the Scalable Bus Protocol. In an

845G chipset-based platform, I/O functions are integrated onto the ICH4.

The chipset platform supports either the integrated graphics device (IGD) on the GMCH or an

external graphics device on AGP. The IGD has 3D, 2D, and video capabilities. The IGD also has

two multiplexed Intel DVO ports to support DVO devices. The GMCH’s AGP interface supports

1X/2X/4X AGP data transfers and 2X/4X AGP Fast Writes, as defined in the Accelerated Graphics

Port Interface Specification, Revision 2.0 for 1.5 V signaling.

In an 845G chipset, system memory can be either a single channel of SDR (Single Data Rate)

SDRAM or DDR (Double Data Rate) SDRAM, with a 64-bit wide data bus. The system memory

size can be up to 2 GB.

Section 1.4 provides an overview of the GMCH. The following sub-section provides an overview

of the ICH4.

Intel® 82801DB I/O Controller Hub 4 (ICH4)

The ICH4 is a highly integrated multifunctional I/O Controller Hub that provides the interface to

the PCI Bus and integrates many of the functions needed in today’s PC platforms. The GMCH and

ICH4 communicate over a dedicated hub interface. The 82801DB ICH4 functions and capabilities

include:

• PCI Rev 2.2 compliant with support for 33 MHz PCI operations

• Supports up to 6 Request/Grant pairs (PCI slots)

• Power management logic support

• Enhanced DMA controller, interrupt controller, and timer functions

• Integrated IDE controller; Ultra ATA/100/66/33

• USB host interface; 3 host controllers and supports 6 USB ports; includes a EHCI high-speed

2.0 USB controller

• Integrated LAN controller

• System Management Bus (SMBus) compatible with most I2C devices; ICH4 has both bus

master and slave capability

• AC ’97 2.3 supported for audio and telephony codecs; up to 6 channels

• Low Pin Count (LPC) interface

• FWH Interface (FWH Flash BIOS support)

• Alert on LAN* (AOL and AOL2)

845GL Datasheet(PDF) 15 Page - Intel Corporation