Production Data
WM9090
w
PD, November 2010, Rev 4.1
23
HEADPHONE MIXER CONTROL
The Headphone Mixer configuration registers are described in Table 8 for the Left Channel
(MIXOUTL) and Table 9 for the Right Channel (MIXOUTR). A subset of the available input PGAs
IN1A, IN1B, IN2A and IN2B is selectable as an input to each of the Headphone Mixers, as illustrated
in Figure 3.
Care should be taken when enabling more than one path to a Headphone Mixer in order to avoid
clipping. The gain of each input path is adjustable using a selectable volume control in each path to
facilitate this.
The Headphone Mixer outputs can be muted or enabled using the MIXOUTL_MUTE and
MIXOUTR_MUTE register bits. The Headphone Mixer volume is also controlled by the Headphone
Output PGAs, as defined in Table 10.
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
R45 (2Dh)
Output Mixer1
6
IN1A_TO_MIXOUTL
0
IN1A to MIXOUTL enable
0 = Disabled
1 = Enabled
2
IN2A_TO_MIXOUTL
0
IN2A to MIXOUTL enable
0 = Disabled
1 = Enabled
R47 (2Fh)
Output Mixer3
8
MIXOUTL_MUTE
1
MIXOUTL Output mute
0 = Un-Mute
1 = Mute
7:6
IN1A_MIXOUTL_VOL
[1:0]
00
IN1A to MIXOUTL volume control
00 = 0dB
01 = -6dB
10 = -9dB
11 = -12dB
3:2
IN2A_MIXOUTL_VOL
[1:0]
00
IN2A to MIXOUTL volume control
00 = 0dB
01 = -6dB
10 = -9dB
11 = -12dB
Table 8 Left Output Mixer (MIXOUTL) Control
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
R46 (2Eh)
Output Mixer2
6
IN1A_TO_MIXOUTR
0
IN1A to MIXOUTR enable
0 = Disabled
1 = Enabled
4
IN1B_TO_MIXOUTR
0
IN1B to MIXOUTR enable
0 = Disabled
1 = Enabled
2
IN2A_TO_MIXOUTR
0
IN2A to MIXOUTR enable
0 = Disabled
1 = Enabled
0
IN2B_TO_MIXOUTR
0
IN2B to MIXOUTR enable
0 = Disabled
1 = Enabled
R48 (30h)
Output Mixer4
8
MIXOUTR_MUTE
1
MIXOUTR Output mute
0 = Un-Mute
1 = Mute