WM8904
Pre-Production
The DC Servo control fields associated with start-up operation are described in Table 52. It is
important to note that, to minimise audible pops/clicks, the Start-Up and DAC Write modes of DC
Servo operation should be commanded as part of a control sequence which includes muting and
shorting of the headphone outputs; a suitable sequence is defined in the default Start-Up sequence.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R68 (44h)
Writing 1 to this bit selects Start-Up
DC Servo mode for LINEOUTR.
7
DCS_TRIG_STAR
TUP_3
0
DC Servo 1
In readback, a value of 1 indicates that
the DC Servo Start-Up correction is in
progress.
Writing 1 to this bit selects Start-Up
DC Servo mode for LINEOUTL.
6
5
4
3
2
1
0
DCS_TRIG_STAR
TUP_2
0
0
0
0
0
0
0
In readback, a value of 1 indicates that
the DC Servo Start-Up correction is in
progress.
Writing 1 to this bit selects Start-Up
DC Servo mode for HPOUTR.
DCS_TRIG_STAR
TUP_1
In readback, a value of 1 indicates that
the DC Servo Start-Up correction is in
progress.
Writing 1 to this bit selects Start-Up
DC Servo mode for HPOUTL.
DCS_TRIG_STAR
TUP_0
In readback, a value of 1 indicates that
the DC Servo Start-Up correction is in
progress.
Writing 1 to this bit selects DAC Write
DC Servo mode for LINEOUTR.
DCS_TRIG_DAC_
WR_3
In readback, a value of 1 indicates that
the DC Servo DAC Write correction is
in progress.
Writing 1 to this bit selects DAC Write
DC Servo mode for LINEOUTL.
DCS_TRIG_DAC_
WR_2
In readback, a value of 1 indicates that
the DC Servo DAC Write correction is
in progress.
Writing 1 to this bit selects DAC Write
DC Servo mode for HPOUTR.
DCS_TRIG_DAC_
WR_1
In readback, a value of 1 indicates that
the DC Servo DAC Write correction is
in progress.
Writing 1 to this bit selects DAC Write
DC Servo mode for HPOUTL.
DCS_TRIG_DAC_
WR_0
In readback, a value of 1 indicates that
the DC Servo DAC Write correction is
in progress.
R67 (43h)
DC Servo enable for LINEOUTR
0 = disabled
3
2
1
0
DCS_ENA_CHAN
_3
0
0
0
0
DC Servo 0
1 = enabled
DC Servo enable for LINEOUTL
0 = disabled
DCS_ENA_CHAN
_2
1 = enabled
DC Servo enable for HPOUTR
0 = disabled
DCS_ENA_CHAN
_1
1 = enabled
DC Servo enable for HPOUTL
0 = disabled
DCS_ENA_CHAN
_0
1 = enabled
PP, Rev 3.3, September 2012
86
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
