82801CA Datasheet, PDF (36/521 Pages) Intel Corporation – I/O Controller Hub 3-S (ICH3-S)

Introduction
AC ’97 2.2 Controller
The Audio Codec ’97, Revision 2.2 specification 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 specification defines the interface between the system logic and the audio
or modem codec, known as the AC ’97 Digital Link.
The ICH3’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 ’97 digital
link. The use of the ICH3-integrated AC ’97 digital link reduces cost and eases migration from
ISA.
By using an audio codec, the AC ’97 digital link allows for cost-effective, high-quality, integrated
audio on Intel’s chipset-based platform. 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
ICH3-integrated digital link allows several external codecs to be connected to the ICH3. The
system designer can provide audio with an audio codec, a modem with a modem codec, or an
integrated audio/modem codec. The digital link is expanded to support two audio codecs or a
combination of an audio and modem codec.
The modem implementations for different countries must be taken into consideration, because
telephone systems may vary. By using a split design, the audio codec can be on-board and the
modem codec can be placed on a riser.
The digital link in the ICH3 is compliant with the Audio Codec ’97, Revision 2.2 specification, so
it supports two codecs with independent PCI functions for audio and modem. Microphone input
and left and right audio channels are supported for a high quality, two-speaker audio solution.
Wake on Ring from Suspend also is supported with the appropriate modem codec.
The ICH3 expands the audio capability with support for up to six channels of PCM audio output
(full AC3 decode). Six-channel audio consists of Front Left, Front Right, Back Left, Back Right,
Center, and Subwoofer, for a complete surround-sound effect. ICH3 has expanded support for two
audio codecs on the AC ’97 digital link.
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Intel^® 82801CA ICH3-S Datasheet