CS4297
CrystalClear™ SoundFusion™ Audio Codec ’97
Stereo Analog Mixer Input Gain Registers (Index 10 - 18h)
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Mute
X
X
GL4
GL3
GL2
GL1
GL0
X
X
X
GR4 GR3 GR2 GR1 GR0
These registers control the gain levels of the analog input sources to the Input Mixer. Each register step for
all registers corresponds to 1.5 dB gain adjustment, thus allowing a range of 12 dB to -34.5 dB of gain.
The MSB of these registers control an analog mute for each source to input mixer. Bits Gx4 - Gx0 of the
registers are used to control the gain levels for each source. The gain mapping for these bits is shown in
Table 3.
Gx4 - Gx0
00000
00001
…
Gain Level
+12 dB
+10.5 dB
…
00111
01000
01001
…
+1.5 dB
0 dB
-1.5 dB
…
11111
-34.5 dB
Table 3. Analog Mixer Input Gain Values
For the stereo source registers (10h through 18h), the default values are 8808h, corresponding to 0 dB at-
tenuation for both channels, and mute on.
Input Mux Select Register (Index 1Ah)
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
X
X
X
X
X
SL2
SL1
SL0
X
X
X
X
X
SR2
SR1
SR0
This register selects the input source to pass to the ADCs for capturing PCM data. The AC’97 specification
allows for independent control of the left and right channels for this mux. Bits SL2 - SL0 provide the de-
code for the left input mux, and bits SR2 - SR0 provide the decode for the right. Shown below are the pos-
sible values for each of these decodes:
Sx2 - Sx0
Record Source
MIC
0
1
2
3
4
5
6
7
CD Input
Video Input
AUX Input
Line Input
Stereo Mix
Mono Mix
Phone Input
Table 4. Input Mux Selection Options
The default power-on value for this register is 0000h, selecting the MIC inputs for both channels.
DS242F5
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