Intel 815 - Manual (Page 119)

I/O Subsystem
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Intel
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815 Chipset Platform Design Guide 119
10.3 AC’97
The ICH implements an AC’97 2.1-compliant digital controller. Any codec attached to the ICH
AC-link must be AC’97 2.1 compliant as well. Contact your codec IHV for information on 2.1-
compliant products. The AC’97 2.1 specification is available on the Intel website:
http://developer.intel.com/pc-supp/platform/ac97/index.htm
The ICH supports the codec combinations listed in Table 27.
Table 27. AC’97 Configuration Combinations
Primary Secondary
Audio (AC) None
Modem (MC) None
Audio (AC) Modem (MC)
Audio/Modem (AMC) None
As shown in Table 27, the ICH does not support two codecs of the same type on the link. For
example, if an AMC is on the link, it must be the only codec. If an AC is on the link, another AC
may not be present.
10.3.1 AC’97 Routing
To ensure the maximum performance of the codec, proper component placement and routing
techniques are required. These techniques include properly isolating the codec, associated audio
circuitry, analog power supplies, and analog ground planes, from the rest of the motherboard. This
includes plane splits and proper routing of signals not associated with the audio section. Contact
your vendor for device-specific recommendations.