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STA380BW
Register description: Sound Terminal compatibility
7.18
Extra volume resolution configuration registers (address
0x3F; 0x40)
Extra volume resolution allows fine volume tuning by steps of 0.125 dB.
The feature is enabled when VRESEN=1, as depicted in
. The overall channel
volume in this case will be CxVol+CxVR (in dB), while the master volume will be
MVOL+MVR (in dB).
Figure 43. Extra resolution volume scheme
If VRESEN = 0 the channel volume will be defined only by the CxVol registers.
Fine tuning steps can be set according to the following table for channels 1, 2,3, and master
volume.
D7
D6
D5
D4
D3
D2
D1
D0
VRESEN
VRESTG
C3VR[1]
C3VR[0]
C2VR[1]
C2VR[0]
C1VR[1]
C1VR[0]
1
0
0
0
0
0
0
0
D7
D6
D5
D4
D3
D2
D1
D0
reserved
reserved
reserved
reserved
reserved
reserved
MVR[1]
MVR[0]
0
0
0
0
0
0
0
0
Table 157. Volume fine-tuning steps
CxVR/MVR
Mode
00
0 dB
01
-0.125 dB
10
-0.25 dB
11
-0.375 dB
Audio Data Out
CxVOL
Soft
Volume
X
X
Audio Data In
VRESEN
VRESTG
CxVR
MVOL or CxVOL’event
1
0
0
1
Audio Data Out
CxVOL
Soft
Volume
X
X
Audio Data In
VRESEN
VRESTG
CxVR
MVOL or CxVOL’event
1
0
0
1
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