SigmaTel, Inc.
Data Sheet
STAC9721
Warm Reset - a warm reset will re-activate the AC-Link without altering the current
STAC9721/23 register values. A warm reset is signaled by driving SYNC high for a
minimum of 1us in the absence of BIT_CLK.
Note: Within normal audio frames, SYNC is a synchronous input. However, in the
absence of BIT_CLK, SYNC is treated as an asynchronous input used in the generation
of a warm reset to the STAC9721/23.
4. STAC9721/23 MIXER
The STAC9721/23 mixer is designed to the AC'97 specification to manage the playback and record of all
digital and analog audio sources in the PC environment. These include:
•
•
•
•
•
•
System Audio: digital PCM input and output for business, games and multimedia
CD/DVD: analog CD/DVD-ROM Redbook audio with internal connections to Codec mixer
Mono microphone: choice of desktop mic, with programmable boost and gain
Speakerphone: use of system mic and speakers for telephone, DSVD, and video conferencing
Video: TV tuner or video capture card with internal connections to Codec mixer
AUX/synth: analog FM or wavetable synthesizer, or other internal source
vol
vol
vol
PCM out
mute
mute
mute
D/A
PC_Beep
Phone
3D
3D
LNLVL
Volume
LNLVL_OUT
MIC1
MIC2
Master
vol
20dB
mute
LINE_OUT
Volume
-6dB
Analog Audio
Sources
Σ
vol
vol
vol
vol
mute
mute
mute
mute
LINE IN
CD
Video
AUX
Mono
Σ
MONO_OUT
Volume
KEY
-6dB
Mono Analog
Stereo Analog
Digital
Σ
Master
Input
A/D
A/D
PCM IN
Volume
. STAC9721/23 Mixer Functional Diagram
Figure 10
19
04/07/00
04/07/00
ETC [ ETC ]
