STAC9721 Datasheet, PDF (19/48 Pages) List of Unclassifed Manufacturers – Stereo AC 97 Codec With Multi-Codec Option

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
PCM out
Analog Audio
Sources
KEY
Mono Analog
Stereo Analog
Digital
D/A
PC_Beep
Phone
MIC1
MIC2
LINE IN
CD
Video
AUX
20dB
vol mute
vol mute
vol mute
vol mute
Σ
vol mute
vol mute
vol mute
vol mute
-6dB
Σ
3D _LNLVL
Volume
-6dB
Σ
3D Master
Volume
Mono
Volume
Master
Input
Volume
A/D
A/D
LNLVL_OUT
LINE_OUT
MONO_OUT
PCM IN
Figure 10. STAC9721/23 Mixer Functional Diagram
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