Intel® 820E Chipset

R

Figure 52. CDC_DN_ENAB# Support Circuitry for Multi-Channel Audio Upgrade

 

Primary

Motherboard

CNR Board

 

 

 

 

Audio

 

 

 

Codec

 

 

 

SDATA_IN

 

 

 

RESET#

 

 

 

 

 

Audio

 

 

 

Codec

 

 

 

RESET#

From AC '97

AC97_RESET#

 

SDATA_IN

 

ID0#

Controller

 

 

 

 

 

 

Vcc

 

 

 

RB

To General

CDC_DN_ENAB#

 

100 k

 

 

Purpose Input

RA

 

 

 

 

 

 

10 k

 

 

To AC '97

SDATA_IN0

 

 

 

 

 

Digital

SDATA_IN1

 

 

Controller

 

 

 

 

 

 

 

 

CNR Connector

Figure 52 shows the circuitry required on the motherboard to support a two-codec down configuration. This circuitry disables the codec on a single codec CNR. Notice that in this configuration the resistor, RB, has been changed to 100 kΩ.

Figure 53. CDC_DN_ENAB# Support Circuitry for Two-Codecs on Motherboard / One-Codec on

CNR

 

Primary

Secondary

Motherboard

CNR Board

 

 

 

 

Audio

Codec

 

 

 

Codec

 

 

 

 

SDATA_IN

SDATA_IN

 

 

 

RESET#

RESET#

 

 

 

 

 

 

Audio

 

 

 

 

Codec

 

AC97_RESET#

 

 

RESET#

From AC '97

 

 

SDATA_IN

 

 

ID0#

Controller

 

 

 

 

 

 

Vcc

 

 

 

 

 

 

 

 

RB

To General

CDC_DN_ENAB#

 

 

100 k

 

 

 

Purpose Input

RA

 

 

 

 

 

 

 

 

10 k

 

 

 

To AC '97

SDATA_IN0

 

 

 

Digital

SDATA_IN1

 

 

 

Controller

 

 

 

 

 

 

 

 

 

 

 

CNR Connector

Figure 53 shows the case of two-codecs down and a dual-codec CNR. In this case, both codecs on the motherboard are disabled (while both on CNR are active) by RA being 10 kΩ and RB being 1 kΩ.

88

Design Guide

Page 88
Image 88
Intel 820E manual Cnr