WM8750L_12 Datasheet, PDF (32/65 Pages) Wolfson Microelectronics plc – Stereo CODEC for Portable Audio Applications

WM8750L
Production Data
OUTPUT MIXERS
The WM8750L provides the option to mix the DAC output signal with analogue line-in signals from the
LINPUT1/2/3, RINPUT1/2/3 pins or a mono differential input (LINPUT1 – RINPUT1) or (LINPUT2 –
RINPUT2), selected by DS (see Table 5) . The level of the mixed-in signals can be controlled with
PGAs (Programmable Gain Amplifiers).
The mono mixer is designed to allow a number of signal combinations to be mixed, including the
possibility of mixing both the right and left channels together to produce a mono output. To prevent
overloading of the mixer when full-scale DAC left and right signals are input, the mixer inputs from the
DAC outputs each have a fixed gain of -6dB. The bypass path inputs to the mono mixer have variable
gain as determined by R38/R39 bits [6:4].
REGISTER
ADDRESS
R34 (22h)
Left Mixer (1)
BIT
LABEL
2:0 LMIXSEL
DEFAULT
000
R36 (24h)
2:0 RMIXSEL
000
Right Mixer
(1)
Table 21 Output Mixer Signal Selection
DESCRIPTION
Left Input Selection for Output Mix
000 = LINPUT1
001 = LINPUT2
010 = LINPUT3
011 = Left ADC Input (after PGA /
MICBOOST)
100 = Differential input
Right Input Selection for Output Mix
000 = RINPUT1
001 = RINPUT2
010 = RINPUT3
011 = Right ADC Input (after PGA /
MICBOOST)
100 = Differential input
REGISTER
ADDRESS
R34 (22h)
Left Mixer
Control (1)
BIT
LABEL
8 LD2LO
7 LI2LO
6:4 LI2LOVOL
[2:0]
R35 (23h)
Left Mixer
Control (2)
8 RD2LO
7 RI2LO
6:4 RI2LOVOL
[2:0]
Table 22 Left Output Mixer Control
DEFAULT
DESCRIPTION
0
0
101
(-9dB)
0
0
101
(-9dB)
Left DAC to Left Mixer
0 = Disable (Mute)
1 = Enable Path
LMIXSEL Signal to Left Mixer
0 = Disable (Mute)
1 = Enable Path
LMIXSEL Signal to Left Mixer Volume
000 = +6dB
… (3dB steps)
111 = -15dB
Right DAC to Left Mixer
0 = Disable (Mute)
1 = Enable Path
RMIXSEL Signal to Left Mixer
0 = Disable (Mute)
1 = Enable Path
RMIXSEL Signal to Left Mixer Volume
000 = +6dB
… (3dB steps)
111 = -15dB
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PD, Rev 4.4, August 2012
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