User's Manual
Intel
®
820 Chipset Design Guide 1-9
Introduction
1.4.5 Manageability
The Intel
®
820 chipset platform integrates several functions designed to manage the system and
lower the total cost of ownership (TCO) 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 integrates a programmable TCO Timer. This timer is used to detect system locks. The first
expiration of the timer generates an SMI# which 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.
CPU Present Indicator
The ICH looks for the CPU to fetch the first instruction after reset. If the CPU does not fetch the
first instruction, the ICH will reboot the system at the safe-mode frequency multiplier.
ECC Error Reporting
Upon detecting an ECC error, the MCH can send one of several messages to the ICH. The MCH
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
disabled 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. The SMBus provides an interface to manage peripherals
(e.g., serial presence detection (SPD) on RIMMs and thermal sensors).
Alert on LAN*
The ICH supports Alert on LAN*. In response to a TCO event (intruder detect, thermal event, CPU
not booting) the ICH sends a message over ALERTCLK and ALERTDATA. A LAN controller can
decode this alert message and send a message over the network to alert the network manager.