Intel 820E manual Function Disable, Intruder Detect, SMBus, Interrupt Controller, Alert on LAN

Intel® 820E Chipset

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Function Disable

The ICH2 provides the ability to disable the following functions: AC’97 Modem, AC’97 Audio, IDE, USB or SMBus. Once disabled, these functions no longer decode I/O, memory or PCI configuration space. Also, no interrupts or power management events are generated by the disabled functions.

Intruder Detect

The ICH2 provides an input signal (INTRUDER#) that can be attached to a switch that is activated when the system case is opened. The ICH2 can be programmed to generate an SMI# or TCO interrupt resulting from an active INTRUDER# signal.

SMBus

The ICH2 integrates an SMBus controller. The SMBus provides an interface to manage peripherals such as serial presence detection (SPD) on RIMMs and thermal sensors. The slave interface allows an external microcontroller to access system resources.

The Intel 820E chipset platform integrates several functions designed to expand the capability of interfacing several components to the system.

Interrupt Controller

The interrupt capabilities of the Intel 820E chipset platform expands support for up to eight PCI interrupt pins and PCI 2.2 message-based interrupts. In addition, the ICH2 supports system bus interrupt delivery.

FWH Flash BIOS

The Intel 820E chipset-based system platform supports firmware hub BIOS memory sizes up to 8 MB, for increased system flexibility.

Alert on LAN*

The ICH2 supports Alert on LAN. In response to a TCO event (intruder detect, thermal event, processor not booting), the ICH2 sends a message over ALERTCLK and ALERTDATA to alert the network manager.

22 Design Guide