82C931 Datasheet, PDF (29/64 Pages) List of Unclassifed Manufacturers – Plug and Play Integrated Audio Controller

82C931
4.2.2 Mixer
The built-in mixer mixes two mono microphone level inputs
(MICL/R) and five stereo analog line level input sources
(LINEL/R, CDL/R, AUXL/R, FML/R, and DACL/R) with indi-
vidual mixer programmable gain and mute control. The
DACL/R stereo analog inputs are routed to a programmable
circuit with 1.5dB steps (total of 32 levels). Internal amplifiers
with a programmable 20dB gain block are provided for the
MIC input (only). The remaining stereo analog inputs are
routed to a programmable gain circuit which can be pro-
grammed in 3dB steps (total of 16 levels). Also, internal
amplifiers with a programmable 20dB gain block are pro-
vided. Level changes only take effect on zero crossings to
minimize audible artifacts. AC coupling is mandatory for
these inputs since any DC offset on the input will be ampli-
fied.
MIXOUTL (mixer record output left) must be connected to
CINL (codec analog input left) with a ceramic capacitor. MIX-
OUTR (mixer record output right) must be connected to CINR
(codec analog input right) with a ceramic capacitor. MIX-
OUT/R are routed via gain control (1.5dB steps: total of 16
levels). Analog output OUTL/R are routed via a master vol-
ume control which provides 0db to 94.5db of attenuation,
adjustable in 3dB steps. The Codec Indirect Registers used
for programming the various functions/gain levels for the
mixer. For details regarding these registers, refer to Table 5-
10 and Table 5-11 in the Register Section. Figure 4-2 shows
a functional block diagram of the mixer.
Figure 4-2 Mixer Block Diagram
MICL/R
LINEL/R
CDL/R
AUXL/R
FML/R
DACL/R
+20dB
16 Levels
–33 to 12dB
(3dB steps)
2
2
ATTEN
+
2
MUTE
2
ATTEN
2
+
MUTE
2
ATTEN
2
+
MUTE
2
ATTEN
2
+
MUTE
2
ATTEN
2
+
MUTE
2
ATTEN
2
+
MUTE
32 Levels
0 to –46.5dB
(1.5dB step)
2
2
2
Mux
2
2
Gain
(16 Levels)
0 to 22.5dB
(1.5dB step)
2
MIXOUTL/R
2
Master Volume
2
ATTEN/MUTE
(32 Levels)
OUTL/R
∑
0 to -93dB
(3dB steps)
Zero
Cross
Detect
Mixer Latch Control
912-3000-035
Revision: 2.1
OPTi
®
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