Production Data
WM8912
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
3
LINEOUTR_RMV
_SHORT
0
Removes LINEOUTR short
0 = LINEOUTR short enabled
1 = LINEOUTR short removed
For normal operation, this bit should
be set as the final step of the
LINEOUTR Enable sequence.
2
1
LINEOUTR_ENA
_OUTP
0
0
Enables LINEOUTR output stage
0 = Disabled
1 = Enabled
For normal operation, this bit should
be set to 1 after the DC offset
cancellation has been scheduled.
LINEOUTR_ENA
_DLY
Enables LINEOUTR intermediate
stage
0 = Disabled
1 = Enabled
For normal operation, this bit should
be set to 1 after the output signal path
has been configured, and before DC
offset cancellation is scheduled. This
bit should be set with at least 20us
delay after LINEOUTR_ENA.
0
LINEOUTR_ENA
0
Enables LINEOUTR input stage
0 = Disabled
1 = Enabled
For normal operation, this bit should
be set as the first step of the
LINEOUTR Enable sequence.
Table 26 Headphone / Line Output Pop Suppression Control
OUTPUT VOLUME CONTROL
Each analogue output can be independently controlled using the registers described in Table 27 (for
Headphone outputs) and Table 28 (for Line outputs). See also the “Analogue Outputs” section for
details of these output pins, including recommended external components.
The volume and mute status of each analogue output can be controlled individually using the register
bits described in Table 27 and Table 28.
To prevent “zipper noise” when a volume adjustment is made, a zero-cross function is provided on all
output paths. When this function is enabled, volume updates will not take place until a zero-crossing
is detected. In the event of a long period without zero-crossings, a timeout will apply. The timeout
must be enabled by setting the TOCLK_ENA bit, as defined in “Clocking and Sample Rates”.
The volume update bits control the loading of the output driver volume data. For example, when
HPOUT_VU is set to 0, the headphone volume data can be loaded into the respective control
register, but will not actually change the gain setting. The Left and Right headphone volume settings
are updated when a 1 is written to HPOUT_VU. This makes it possible to update the gain of a
Left/Right pair of output paths simultaneously.
PD, Rev 4.0, September 2010
41
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
