82801AB datasheet(27/414 Pages) INTEL

27 / 414 page

82801AA and 82801AB Datasheet

1-7

Introduction

Manageability

The ICH integrates several functions designed to manage the system and lower the total cost of

ownership (TC0) of the system. These system management functions are designed to report errors,

diagnose the system, and recover from system lockups without the aid of an external

microcontroller.

• TCO Timer. The ICH’s integrated programmable TC0 Timer is used to detect system locks.

The first expiration of the timer generates an SMI# that the system can use to recover from a

software lock. The second expiration of the timer causes a system reset to recover from a

hardware lock.

• Processor Present Indicator. The ICH looks for the processor to fetch the first instruction

after reset. If the processor does not fetch the first instruction, the ICH will reboot the system

at the safe-mode frequency multiplier.

• ECC Error Reporting. When detecting an ECC error, the host controller has the ability to

send one of several messages to the ICH. The host controller can instruct the ICH to generate

either an SMI#, NMI, SERR#, or TCO interrupt.

• Function Disable. The ICH 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 from the disable functions.

• Intruder Detect. The ICH provides an input signal (INTRUDER#) that can be attached to a

switch that is activated by the system case being opened. The ICH can be programmed to

generate an SMI# or TCO interrupt due to an active INTRUDER# signal.

• SMBus. The ICH integrates an SMBus controller that provides an interface to manage

peripherals (e.g., serial presence detection (SPD) or RIMMs and thermal sensors).

• Alert-On-LAN (82801AA only). The ICH (82801AA only) supports Alert-On-LAN. In

response to a TCO event (intruder detect, thermal event, processor not booting) the ICH sends

a message over the SMBus. A LAN controller can decode this SMBus message and send a

message over the network to alert the network manager.

82801AB Datasheet(PDF) 27 Page - Intel Corporation