wm8352 Wolfson Microelectronics plc, wm8352 Datasheet - Page 67

• Manufacturer Part Number: wm8352
• Description: Wolfson Audioplus? Stereo Codec With Power Management
• Manufacturer: Wolfson Microelectronics plc

Production Data
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13.4.5
The WM8352 provides a programmable, low-noise bias voltage for condenser electret microphones
on the MICBIAS pin.
R8 (08h)
Power Mgmt 1
R74 (4Ah)
Mic Bias
Control
Note: MICB_ENA can be accessed through R8 or through R74. Reading from or writing to either
register location has the same effect.
Table 23 Controlling the Microphone Bias Voltage
13.4.6
The WM8352 provides two additional analogue input pins, IN3L and IN3R, for line-level audio or
“beep” signals. Each pin has a simple input buffer whose output signal can be digitised in the audio
ADC and/or mixed into the output signal path. The Right input IN3R may also be connected to the
Output Beep Mixer, for output on OUT2R (see Table 42). The input buffers have a nominal default
gain of -1 (0dB).
Figure 38 Auxiliary Input Buffers
ADDRESS
IN3R
IN3L
MICROPHONE BIASING
AUXILIARY INPUTS (IN3L AND IN3R)
IN3R_SHORT, R73[14]
IN3L_SHORT, R73[6]
BIT
15
14
4
20k
20k
MICB_ENA
MICB_ENA
MICB_SEL
LABEL
Vmid
Vmid
DEFAULT
-
+
-
+
20k
20k
0
0
Microphone bias enable
0 = OFF (high impedance output)
1 = ON
Microphone bias voltage control:
0 = 0.9 * AVDD
1 = 0.75 * AVDD
To:
Right Input Mixer,
Right Output Mixer,
Output Beep Mixer
To:
Left Input Mixer,
Left Output Mixer
DESCRIPTION
PD, June 2009, Rev 4.1
WM8352
67