WM8983_10 Datasheet, PDF (57/124 Pages) Wolfson Microelectronics plc – Mobile Multimedia CODEC with 1W Speaker Driver

Production Data
WM8983
The analogue outputs from the DACs can then be mixed with the aux analogue inputs and the ADC
analogue inputs. The mix is fed to the output drivers for headphone (LOUT1/ROUT1,
LOUT2/ROUT2) or line (OUT3/OUT4). OUT3 and OUT4 have additional mixers which allow them to
output different signals to the headphone and line outputs.
DIGITAL PLAYBACK (DAC) PATH
Digital data is passed to the WM8983 via the flexible audio interface and is then passed through a
variety of advanced digital filters as shown in Figure 30 to the hi-fi DACs. The DACs are enabled by
the DACENL/R register bits.
REGISTER
ADDRESS
R3
Power
Management 3
BIT LABEL
0
DACENL
1
DACENR
Table 28 DAC Enable Control
DEFAULT
DESCRIPTION
0
Left channel DAC enable
0 = DAC disabled
1 = DAC enabled
0
Right channel DAC enable
0 = DAC disabled
1 = DAC enabled
The WM8983 also has a Soft Mute function, which when enabled, gradually attenuates the volume of
the digital signal to zero. When disabled, the gain will ramp back up to the digital gain setting. This
function is enabled by default. To play back an audio signal, it must first be disabled by setting the
SOFTMUTE bit to zero.
REGISTER
ADDRESS
R10
DAC Control
BIT
LABEL
0 DACPOL
1 DACRPOL
2 AMUTE
3 DACOSR
6 SOFTMUTE
Table 29 DAC Control Register
DEFAULT
0
0
0
0
0
DESCRIPTION
Left DAC output polarity:
0 = non-inverted
1 = inverted (180 degrees phase shift)
Right DAC output polarity:
0 = non-inverted
1 = inverted (180 degrees phase shift)
Automute enable
0 = Amute disabled
1 = Amute enabled
DAC oversampling rate:
0 = 64x (lowest power)
1 = 128x (best performance)
Softmute enable:
0 = Enabled
1 = Disabled
The digital audio data is converted to oversampled bit streams in the on-chip, true 24-bit digital
interpolation filters. The bitstream data enters the multi-bit, sigma-delta DACs, which convert it to a
high quality analogue audio signal. The multi-bit DAC architecture reduces high frequency noise and
sensitivity to clock jitter. It also uses a Dynamic Element Matching technique for high linearity and low
distortion.
The DAC output phase defaults to non-inverted. Setting DACLPOL will invert the DAC output phase
on the left channel and DACRPOL inverts the phase on the right channel.
AUTO-MUTE
The DAC has an auto-mute function which applies an analogue mute when 1024 consecutive zeros
are detected. The mute is released as soon as a non-zero sample is detected. Auto-mute can be
disabled using the AMUTE control bit.
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PD, Rev 4.3, May 2010
57