wm9714l Wolfson Microelectronics plc, wm9714l Datasheet - Page 52

• Manufacturer Part Number: wm9714l
• Description: Ac?97 Audio Codec
• Manufacturer: Wolfson Microelectronics plc

WM9714L
AUDIO MIXERS
MIXER OVERVIEW
HEADPHONE MIXERS
SPEAKER MIXER
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The WM9714L has four separate low-power audio mixers to cover all audio functions required by
smartphones, PDAs and handheld computers. These mixers are used to drive the audio outputs
HPL, HPR, MONO, SPKL, SPKR, OUT3 and OUT4. There are also two inverters used to provide
differential output signals (e.g. for driving BTL loads)
There are two headphone mixers, headphone mixer left and headphone mixer right (HPMIXL and
HPMIXR). These mixers are the stereo output driver source. They are used to drive the stereo
outputs HPL and HPR. They can also be used to drive SPKL and SPKR outputs and, when used in
conjunction with OUT3 and OUT4, they can be configured to drive complementary signals through
the two output inverters to support bridge-tied load (BTL) stereo loudspeaker outputs. The following
signals can be mixed into the headphone path:
In a typical smartphone application, the headphone signal is a mix of MONOIN / VXDAC and
sidetone (for phone calls) and the stereo DAC signal (for music playback).
When not in use the headphone mixers can be powered down using the Powerdown register bits
HPLX and HPRX (register 3Ch, bits [3:2]).
The speaker mixer (SPKMIX) is a mono source. It is typically used to drive a mono loudspeaker in
BTL configuration. The following signals can be mixed into the speaker path:
In a typical smartphone application, the speaker signal is a mix of AUXDAC (for system alerts or ring
tone playback), MONOIN / VXDAC (for speakerphone function), and PC_BEEP (for externally
generated ring tones).
Note that when selected the stereo input pairs LINEL/R and DACL/R are summed and attenuated by
-6dB so that 0dBFS signals on each channel sum to give a 0dBFS mono signal.
When not in use the speaker mixer can be powered down using the Powerdown register bit SPKX
(register 3Ch, bit 1).
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MONOIN (controlled by register 08h, see “Audio Inputs”)
LINEL/R (controlled by register 0Ah, see “Audio Inputs”)
the output of the Record PGA (controlled by register 14h, see “Audio ADC”,
“Record Gain”)
the stereo DAC signal (controlled by register 0Ch, see “Audio DACs”)
the MIC signal (controlled by register 10h, see “Audio Inputs”)
PC_BEEP (controlled by register 16h, see “Audio Inputs”)
the VXDAC signal (controlled by register 18h, see “Audio DACs”)
the AUXDAC signal (controlled by register 1Ah, see “Auxiliary DAC”)
MONOIN (controlled by register 08h, see “Audio Inputs”)
LINEL/R (controlled by register 0Ah, see “Audio Inputs”)
the stereo DAC signal (controlled by register 0Ch, see “Audio DACs”)
PC_BEEP (controlled by register 16h, see “Audio Inputs”)
the VXDAC signal (controlled by register 18h, see “Audio DACs”)
the AUXDAC signal (controlled by register 1Ah, see “Auxiliary DAC”)
PP, Rev 3.2, October 2008
Pre-Production
52