TLC320AD90C Datasheet, PDF (14/51 Pages) Texas Instruments – Stereo Audio Codec

2 Functional Description
2.1 Analog Input/Output Ports
2.1.1 Analog Outputs
The TLC320AD90C mixer generates the following two distinct audio outputs:
• A stereo mix of all sources for output to the speakers, headset, and LINE_OUT output
• A mono, mic only, or mix of all sources (except PHONE and PC_BEEP) for speakerphone output
(MONO_OUT)
2.1.2 Analog Inputs
The TLC320AD90C supports all analog audio inputs required by the audio codec ‘97 (AC‘97) specification.
Specifically, the device supports the playback and record of all digital and analog sources likely to be present
in PCs. These sources include the following:
• 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 or headset mic with programmable boost and gain
• Speakerphone: use of system mic and speakers for telephony, DSVD, and video conferencing
• Stereo line in: analog external line level source from consumer audio, video camera, etc
• Video: TV tuner or video capture card with internal connections to codec mixer
• Aux/synth: analog FM or wavetable synthesizer or other internal source
The analog inputs connect to a stereo analog mixer as well as a stereo multiplexer. The mixer is used for
playback or analog pass-through. The multiplexer is used during record.
The multiplexer offers the capability to record any of the audio sources or the outgoing mix of all sources.
The multiplexer implementation is more efficient than an independent mix and offers simple monitoring when
a mix is recorded: what you hear is what you get (WYHIWYG). The mono and stereo mix also provides
excellent echo cancellation reference signals.
The TLC320AD90C supports the following full range of input options (the audio driver may maintain a
consistent record input level for each multiplexer option):
• Any mono or stereo source
• Mono or stereo mix of all sources
• Two-channel input with mono output reference (mic and stereo mix for stereo echo cancellation)
2.2 Digital Interface
The TLC320AD90C, per the AC‘97 specification, incorporates a 5-wire serial digital interface to a digital
controller. The AC-Link specifies a bidirectional, fixed rate, serial PCM digital stream. The interface handles
multiple input and output audio streams as well as control register accesses by employing a time division
multiplexed (TDM) protocol.
The AC-Link architecture divides each audio frame into 12 outgoing and 12 incoming data streams, each
with 20-bit sample resolution.
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