Production Data
WM8976
w
PD, Rev 4.5, November 2011
23
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
R44
Input
Control
0
LIP2INPPGA
1
Connect LIP pin to input PGA amplifier
positive terminal.
0 = LIP not connected to input PGA
1 = input PGA amplifier positive terminal
connected to LIP (constant input
impedance)
1
LIN2INPPGA
1
Connect LIN pin to input PGA negative
terminal.
0=LIN not connected to input PGA
1=LIN connected to input PGA amplifier
negative terminal.
2
L2_2INPPGA
0
Connect L2 pin to input PGA positive
terminal.
0=L2 not connected to input PGA
1=L2 connected to input PGA amplifier
positive terminal (constant input
impedance).
Table 5 Input PGA Control
INPUT PGA VOLUME CONTROL
The input microphone PGA has a gain range from -12dB to +35.25dB in 0.75dB steps. The gain from
the LIN input to the PGA output and from the L2 amplifier to the PGA output is always common and
controlled by the register bits INPPGAVOLL[5:0]. These register bits also affect the LIP pin when
LIP2INPPGA=1, the L2 pin when L2_2INPPGA=1 and the L2 pin when L2_2INPPGA=1.
When the Automatic Level Control (ALC) is enabled the input PGA gains are controlled automatically
and the INPPGAVOLL bits should not be used.
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
R45
Input PGA
volume
control
5:0
INPPGAVOLL
010000
Input PGA volume
000000 = -12dB
000001 = -11.25db
.
010000 = 0dB
.
111111 = 35.25dB
6
INPPGAMUTEL
0
Mute control for input PGA:
0=Input PGA not muted, normal
operation
1=Input PGA muted (and disconnected
from the following input BOOST stage).
7
INPPGAZCL
0
Input PGA zero cross enable:
0=Update gain when gain register
changes
1=Update gain on 1
st
zero cross after
gain register write.
8 INPPGAUPDATE
Not
latched
INPPGAVOLL volume does not update
until a 1 is written to INPPGAUPDATE
R32
ALC control
1
8
ALCSEL
0
ALC function select:
0=ALC off
1=ALC on
Table 6 Input PGA Volume Control
Содержание WM8976
Страница 13: ...Production Data WM8976 w PD Rev 4 5 November 2011 13 AUDIO PATHS OVERVIEW Figure 1 WM8976 Audio Signal Paths...
Страница 40: ...WM8976 Production Data w PD Rev 4 5 November 2011 40 Figure 21 ALCLVL...
Страница 43: ...Production Data WM8976 w PD Rev 4 5 November 2011 43 Figure 23 ALC Operation Above Noise Gate Threshold...
Страница 52: ...WM8976 Production Data w PD Rev 4 5 November 2011 52 Figure 27 Left Right Output Channel Mixers...