Intel 820E manual System Overview

Intel® 820E Chipset

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1.3.System Overview

The Intel 820E chipset is designed for Intel® Pentium® III microprocessors and is the first chipset to support the integrated LAN capability and expanded USB capability. It supports the 4⋅ capability of the AGP 2.0 Interface Specification and it supports the 400 MHz Direct RDRAM* interface. The 400 MHz, 16-bit, double-clockedDirect RDRAM interface provides 1.6-GB/s access to main memory. To provide more efficient communication between chipset components, the hub interface component interconnect is designed into the Intel 820E chipset.

Support of AGP 4⋅ , 400 MHz Direct RDRAM and the hub interface provides a balanced system architecture for the Pentium III processor, minimizing bottlenecks and increasing system performance. By increasing memory bandwidth to 1.6 GB/s by means of 400 MHz Direct RDRAM and by increasing the graphics bandwidth to 1 GB/s by means of AGP 4⋅ , the Intel 820E chipset delivers the data throughput necessary to take advantage of the high performance provided by the powerful Pentium III processors.

In addition, the Intel 820E chipset architecture enables security and manageability infrastructures through the Firmware Hub (FWH)component.

The ACPI-compliant Intel 820E chipset platform can support the Full-On, Stop Grant, Suspend to RAM, Suspend to Disk, and Soft-Off power management states. Through the use of the integrated LAN functions, the Intel 820E chipset also supports Wake on LAN* for remote administration and troubleshooting.

The Intel 820E chipset architecture eliminates the need for the ISA expansion bus traditionally integrated into the I/O subsystem of Intel chipsets. This eliminates many conflicts experienced when installing hardware and drivers into legacy ISA systems. The elimination of ISA provides true plug and play for the Intel 820E chipset platform. Traditionally, the ISA interface was used for audio and modem devices. The addition of AC’97 allows the OEM to use software-configurable AC’97 audio and modem encoders/decoders (codecs), instead of traditional ISA devices. The 82801BA ICH2 component expands the support of AC’97 to include up to 6-channel audio. The ISA bus can be implemented with a PCI-to- ISA bridge from an external component supplier.

The Intel 820E chipset contains two core components: the Memory Controller Hub (MCH) and the I/O Controller Hub 2 (ICH2). The MCH integrates the 133 MHz processor system bus controller, an AGP

2.0controller, a 400 MHz Direct RDRAM controller, and a high-speed hub interface for communication with the ICH2. The ICH2 integrates an Ultra ATA/100 controller, two USB host controllers, an LPC interface controller, an FWH Flash BIOS interface controller, a PCI interface controller, an AC’97 digital controller, an integrated LAN controller, and a hub interface for communication with the MCH. The Intel 820E chipset provides the data buffering and interface arbitration required to ensure that the system interfaces operate efficiently and provide the system bandwidth necessary to obtain peak performance with the Pentium III processor.

Design Guide 15