wm9714l Wolfson Microelectronics plc, wm9714l Datasheet - Page 44

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

WM9714L
AUDIO INPUTS
LINE INPUT
w
The following sections give an overview of the analogue audio input pins and their function. For more
information on recommended external components, please refer to the “Applications Information”
section.
The LINEL and LINER inputs are designed to record line level signals, and/or to mix into one of the
analogue outputs.
Both pins are directly connected to the record selector. The record PGA adjusts the recording
volume, controlled by register 12h or by the ALC function.
For analogue mixing, the line input signals pass through a separate PGA, controlled by register 0Ah.
The signals can be mixed into the headphone, speaker and mono mixer paths (see “Audio Mixers”).
Each LINE-to-mixer path has an independent mute bit. When all LINE-to-mixer paths are muted the
line PGA is muted automatically. When the line inputs are not used, the line PGA can be switched off
to save power (see “Power Management” section).
LINEL and LINER are biased internally to the reference voltage VREF. Whenever the inputs are
muted or the device placed into standby mode, the inputs remain biased to VREF using special anti-
thump circuitry to suppress any audible clicks when changing inputs.
Table 22 Line Input Control
Additionally, line inputs can be used as single-ended microphone inputs through the record mux to
provide a clickless ALC function by bypassing offset introduced through the microphone pre-amps.
Note that the line inputs to the mixers should all be deselected if this is input configuration is used.
0Ah
REGISTER
ADDRESS
15
14
13
12:8
4:0
BIT
L2H
L2S
L2M
LINEL
VOL
LINER
VOL
LABEL
1
1
1
01000
(0dB)
01000
(0dB)
DEFAULT
LINE to Headphone Mixer Mute Control
1 = Mute
0 = No mute
LINE to Speaker Mixer Mute Control
1 = Mute
0 = No mute
LINE to Mono Mixer Mute Control
1 = Mute
0 = No mute
LINEL to Mixers Volume Control
00000 = +12dB
… (1.5dB steps)
11111 = -34.5dB
LINER to Mixers Volume Control
00000 = +12dB
… (1.5dB steps)
11111 = -34.5dB
DESCRIPTION
PP, Rev 3.2, October 2008
Pre-Production
44