Figure 101. Cdc_Dn_Enab# Support Circuitry For Multi-Channel Audio Upgrade; Figure 102. Cdc_Dn_Enab# Support Circuitry For Two-Codecs On Motherboard / One-Codec On Cnr - Intel Pentium 4 Design Manual

I/O Controller Hub 2

Figure 101. CDC_DN_ENAB# Support Circuitry for Multi-Channel Audio Upgrade

From AC '97
Controller
To General
Purpose Input
To AC '97
Digital
Controller
Figure 102 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, R
Figure 102. CDC_DN_ENAB# Support Circuitry for Two-Codecs on Motherboard / One-Codec
on CNR
From AC '97
Controller
To General
Purpose Input
To AC '97
Digital
Controller
Figure 103 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 R
1 kΩ.
146
Prim ary
Audio
Codec
SDAT A_IN
AC97_RESET#
CDC_DN_ENAB#
SDATA_IN0
SDATA_IN1
, has been changed to 100 kΩ.
B
Prim ary
Audio
Codec
SDAT A_IN
RESET #
AC97_RESET#
CDC_DN_ENAB#
R
A
10kohm s
SDATA_IN0
SDATA_IN1
® ®
Intel Pentium 4 Processor / Intel
Motherboard
RESET #
R
A
10kohm s
Motherboard
Secondary
Codec
SDAT A_IN
RESET#
®
850 Chipset Family Platform Design Guide
CNR Board
Audio
Codec
RESET #
SDAT A_IN
ID0#
Vcc
R
B
100kohm s
CNR Connector
CNR Board
Audio
Codec
RESET #
SDAT A_IN
ID0#
Vcc
R
B
100kohm s
CNR Connector
being 10 kΩ and R being
A B
R