WM8734 ETC-unknow, WM8734 Datasheet - Page 13

• Manufacturer Part Number: WM8734
• Description: Stereo Audio Codec
• Manufacturer: ETC-unknow

WM8734
w
Figure 8 Line Input Schematic
The gain between the line inputs and the ADC is logarithmically adjustable from +12dB to –34.5dB in
1.5dB steps under software control. The ADC Full Scale input is 1.0V rms at AVDD = 3.3 volts. Any
voltage greater than full scale will possibly overload the ADC and cause distortion. Note that the full
scale input tracks directly with AVDD. The gain is independently adjustable on both Right and Left
Line Inputs. However, by setting the INBOTH bit whilst programming the volume control, both
channels are simultaneously updated with the same value. Use of INBOTH reduces the required
number of software writes required. The line inputs to the ADC can be muted in the analogue domain
under software control. The software control registers are shown below.
Table 1 Line Input Software Control
0000000
Left Line In
0000001
Right Line In
REGISTER
ADDRESS
LINEIN
4:0
7
8
4:0
7
8
BIT
12.5K
LINVOL[4:0]
LINMUTE
LRINBOTH
RINVOL[4:0]
RINMUTE
RLINBOTH
LABEL
VMID
10111
( 0dB )
1
0
10111
( 0dB )
1
0
DEFAULT
Left Channel Line Input Volume
Control
11111 = +12dB . . 1.5dB steps down
to 00000 = -34.5dB
Left Channel Line Input Mute to ADC
1 = Enable Mute
0 = Disable Mute
Left to Right Channel Line Input
Volume and Mute Data Load Control
1 = Enable Simultaneous Load of
LINVOL[4:0] and LINMUTE to
RINVOL[4:0] and RINMUTE
0 = Disable Simultaneous Load
Right Channel Line Input Volume
Control
11111 = +12dB . .1.5dB steps down
to 00000 = -34.5dB
Right Channel Line Input Mute to
ADC
1 = Enable Mute
0 = Disable Mute
Right to Left Channel Line Input
Volume and Mute Data Load Control
1 = Enable Simultaneous Load of
RINVOL[4:0] and RINMUTE to
LINVOL[4:0] and LINMUTE
0 = Disable Simultaneous Load
DESCRIPTION
AI Rev 2.2 November 2001
Advanced Information
ADC
To
13