82801BA Datasheet, PDF (36/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Introduction
AC’97 2.1 Controller
The Audio Codec ’97 (AC’97) 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 ICH2’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 ICH2-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
ICH2-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. 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. Intel is developing an AC’97 digital link connector. With a
single integrated codec, or AMC, both audio and modem can be routed to a connector near the rear
panel, where the external ports can be located.
The digital link in the ICH2 is compliant with revision 2.1 of the AC’97, 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 ICH2 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 Woofer, for a complete surround-sound effect. ICH2 has expanded support for two
audio codecs on the AC’97 digital link.
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82801BA ICH2 and 82801BAM ICH2-M Datasheet