WM8978 Wolfson Microelectronics Ltd., WM8978 Datasheet - Page 29

• Manufacturer Part Number: WM8978
• Description: The WM8978 is a low power, high quality stereo codec designed for portable applications such as Digital still camera or Digital Camcorde
• Manufacturer: Wolfson Microelectronics Ltd.

Preliminary Technical Data
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Table 8 Input PGA Volume Control
VOLUME UPDATES
Volume settings will not be applied to the PGAs until a '1' is written to one of the INPPGAUPDATE
bits. This is to allow left and right channels to be updated at the same time, as shown in Figure 12.
R45
Left channel
input PGA
volume
control
R46
Right
channel
input PGA
volume
control
R32
ALC control
1
REGISTER
ADDRESS
5:0
6
7
8
5:0
6
7
8
8:7
BIT
INPPGAVOLL
INPPGAMUTEL
INPPGAZCL
INPPGAUPDATE
INPPGAVOLR
INPPGAMUTER
INPPGAZCR
INPPGAUPDATE
ALCSEL
LABEL
010000
0
0
Not
latched
010000
0
0
Not
latched
00
DEFAULT
Left channel input PGA volume
000000 = -12dB
000001 = -11.25db
.
010000 = 0dB
.
111111 = 35.25dB
Mute control for left channel input PGA:
0=Input PGA not muted, normal
operation
1=Input PGA muted (and disconnected
from the following input BOOST stage).
Left channel input PGA zero cross
enable:
0=Update gain when gain register
changes
1=Update gain on 1
gain register write.
INPPGAVOLL and INPPGAVOLR
volume do not update until a 1 is written
to INPPGAUPDATE (in reg 45 or 46)
Right channel input PGA volume
000000 = -12dB
000001 = -11.25db
.
010000 = 0dB
.
111111 = +35.25dB
Mute control for right channel input
PGA:
0=Input PGA not muted, normal
operation
1=Input PGA muted (and disconnected
from the following input BOOST stage).
Right channel input PGA zero cross
enable:
0=Update gain when gain register
changes
1=Update gain on 1
gain register write.
INPPGAVOLL and INPPGAVOLR
volume do not update until a 1 is written
to INPPGAUPDATE (in reg 45 or 46)
ALC function select:
00=ALC off
01=ALC right only
10=ALC left only
11=ALC both on
PTD Rev 2.6 November 2005
DESCRIPTION
st
st
zero cross after
zero cross after
WM8978
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