Manageability And Other Enhancements; Ac '97 6-Channel Support - Intel 815EG Design Manual

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1.4.3.8

Manageability and Other Enhancements

The 815EG 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.
SMBus
The ICH2 integrates an SMBus controller. The SMBus provides an interface for managing
peripherals such as serial presence detection (SPD) and thermal sensors. The slave interface allows
an external microcontroller to access system resources.
Interrupt Controller
The interrupt capabilities of the platform expand support for up to 8 PCI interrupt pins and
PCI 2.2 message-based interrupts. In addition, the ICH2 supports system bus interrupt delivery.
Firmware Hub (FWH)
The platform supports firmware hub BIOS memory sizes up to 8 MB for increased system
flexibility.
1.4.3.9

AC '97 6-Channel Support

The AC '97 v2.2 defines a digital interface that can be used to attach an audio codec (AC), a
modem codec (MC), an audio/modem codec (AMC), or both an AC and an MC. The AC '97 v2.2
defines the interface between the system logic and the audio or modem codec known as the "AC-
link."
The 815EG chipset platform's AC '97 (with the appropriate codecs) not only replaces ISA audio
and modem functionality, but also improves overall platform integration by incorporating the AC-
link. Using the platform's integrated AC-link reduces cost and eases migration from ISA.
By using an audio codec, the AC-link allows for cost-effective, high-quality, integrated audio. In
addition, an AC '97 soft modem can be implemented with the use of a modem codec. Several
system options exist when implementing AC '97. The 815EG chipset platform's integrated digital
link allows several external codecs to be connected to the ICH2. The system designer can provide
audio with an audio codec, a modem with a modem codec, or an integrated audio/modem codec
(Figure 3c). The digital link is expanded to support two audio codecs (Figure 3a) or a combination
of an audio and modem codec (Figure 3b).
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Intel 815EG Chipset Platform Design Guide
Introduction
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