wm8982gefl-v Wolfson Microelectronics plc, wm8982gefl-v Datasheet - Page 24

• Manufacturer Part Number: wm8982gefl-v
• Description: Mono Codec With Speaker Driver And Video Buffer
• Manufacturer: Wolfson Microelectronics plc

WM8982
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AUXILLIARY INPUTS
There are two auxiliary inputs, AUX1 and AUX2 which can be used for a variety of purposes such as
line inputs or as a ‘beep’ input signal to be mixed with the outputs.
The AUX1 input can be used as a line input to the input BOOST stage which has gain adjust of -
12dB to +6dB in 3dB steps (plus off). See the INPUT BOOST section for further details.
The AUX1/2 inputs can also be mixed into the output channel mixers, with a gain of -15dB to +6dB
plus off.
In addition the AUX2 input can be summed into the speaker output path (SPKOUTN) with a gain
adjust of -15 to +6dB. This allows a ‘beep’ input to be output on the speaker outputs only without
affecting the lineout signal.
INPUT BOOST
The input PGA stage is followed by an input BOOST circuit.
selectable inputs: the input microphone PGA output, the AUX amplifier output and the LINEIN input
pin (can be used as a line input, bypassing the input PGA). These three inputs can be mixed
together and have individual gain boost/adjust as shown in Figure 14.
Figure 14 Input Boost Stage
The input PGA paths can have a +20dB boost (PGABOOST=1) , a 0dB pass through
(PGABOOST=0) or be completely isolated from the input boost circuit (INPPGAMUTE=1).
Table 6 Input BOOST Stage Control
The Auxiliary amplifier path to the BOOST stages is controlled by the AUX1_2BOOSTVOL[2:0]
register bits. When AUX1_2BOOSTVOL=000 this path is completely disconnected from the BOOST
stage. Settings 001 through to 111 control the gain in 3dB steps from -12dB to +6dB.
The LINEIN path to the BOOST stage is controlled by the LINE2BOOSTVOL[2:0] register bits.
When LINE2BOOSTVOL=000 the LINEIN input pin is completely disconnected from the BOOST
stage. Settings 001 through to 111 control the gain in 3dB steps from -12dB to +6dB.
R47
Input BOOST
control
REGISTER
ADDRESS
8
BIT
PGABOOST
LABEL
1
DEFAULT
0 = PGA output has +0dB gain
through input BOOST stage.
1 = PGA output has +20dB gain
through input BOOST stage.
Boost enable for input PGA:
The input BOOST circuit has 3
PP, Rev 3.2, September 2008
DESCRIPTION
Pre-Production
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