User's Manual

Intel
®
820 Chipset Design Guide 2-61
Layout/Routing Guidelines
2.14 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 on the Intel website. The ICH supports the
following combinations of codecs:
As shown in the table, 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
cannot be present.
Intel has developed a common connector specification known as the Audio/Modem Riser (AMR).
This specification defines a mechanism for allowing OEM plug-in card options.
Figure 2-51. Resistor Requirements for Secondary IDE Connector
5.6k
ohm
Reset#
Secondary IDE Connector
ICH
10k
ohm
SDD[15:8]
SDD[6:0]
PCIRST_BUF#*
22 - 47 ohm
SDA[2:0]
SDCS1#
SDCS3#
SDIOR#
SDIOW#
SDDREQ
SIORDY
SDD[7]
*Due to ringing, PCIRST# must be buffered.
1k
ohm
5V
470 ohm
CSEL
Pin 32
N.C.
SDDACK#
IRQ15
5V
8.2k-10k
ohm
Pin 34
N.C.
Table 2-15. ICH Codec Options
Primary Secondary
Audio (AC) None
Modem (MC) None
Audio (AC) Modem (MC)
Audio/Modem (AMC) None