Production Data
WM8912
DIGITAL MIXING
The digital DAC data can be controlled in various ways to support a range of different usage modes.
Data from either of the digital audio interface channels can be routed to either the left or the right
DAC. The DACs can be configured as a mono mix of the two audio channels. See "Digital Audio
Interface Control" for more information on the audio interface.
The WM8912 provides a Dynamic Range Control (DRC) feature, which can apply compression and
gain adjustment in the digital domain to the DAC signal path. This is effective in controlling signal
levels under conditions where input amplitude is unknown or varies over a wide range. See “Dynamic
Range Control (DRC)” for further details.
The W8912 also incorporates the ReTuneTM Mobile 5-band parametric equaliser with fully
programmable coefficients for optimization of speaker characteristics or for tailoring the response
according to user preferences. See “ReTuneTM Mobile Parametric Equalizer (EQ)” for further details.
DAC INTERFACE ROUTING AND CONTROL
The input data source for each DAC can be changed under software control using register bits
AIFDACL_SRC and AIFDACR_SRC. The polarity of each DAC input may also be modified using
register bits DACL_DATINV and DACR_DATINV. These register bits are described in Table 13.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R24 (18h)
12
DACL_DATINV
0
Left DAC Invert
Audio
Interface 0
0 = Left DAC output not inverted
1 = Left DAC output inverted
11
5
DACR_DATINV
AIFDACL_SRC
AIFDACR_SRC
0
0
1
Right DAC Invert
0 = Right DAC output not inverted
1 = Right DAC output inverted
Left DAC Data Source Select
0 = Left DAC outputs left interface data
1 = Left DAC outputs right interface data
Right DAC Data Source Select
0 = Right DAC outputs left interface data
4
1 = Right DAC outputs right interface
data
Table 13 DAC Routing and Control
DAC INTERFACE VOLUME BOOST
A digital gain function is available at the audio interface to boost the DAC volume when a small
signal is received on DACDAT. This is controlled using register bits DAC_BOOST [1:0]. To prevent
clipping at the DAC input, this function should not be used when the boosted DAC data is expected
to be greater than 0dBFS.
The digital interface volume is controlled as shown in Table 14.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R24 (18h)
10:9
DAC_BOOST
[1:0]
00
DAC Input Volume Boost
00 = 0dB
Audio
Interface 0
01 = +6dB (Input data must not
exceed -6dBFS)
10 = +12dB (Input data must not
exceed -12dBFS)
11 = +18dB (Input data must not
exceed -18dBFS)
Table 14 DAC Interface Volume Boost
PD, Rev 4.0, September 2010
31
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