WM8750L
Production Data
3D STEREO ENHANCEMENT
The WM8750L has a digital 3D enhancement option to artificially increase the separation between the
left and right channels. This effect can be used for recording or playback, but not for both
simultaneously. Selection of 3D for record or playback is controlled by register bit MODE3D.
Important:
Switching the 3D filter from record to playback or from playback to record may only be done when
ADC and DAC are disabled. The WM8750L control interface will only allow MODE3D to be changed
when ADC and DAC are disabled (i.e. bits ADCL, ADCR, DACL and DACR in reg. 26 / 1Ah are all
zero).
The 3D enhancement function is activated by the 3DEN bit, and has two programmable parameters.
The 3DDEPTH setting controls the degree of stereo expansion. Additionally, one of four filter
characteristics can be selected for the 3D processing, using the 3DVC and 3DLC control bits.
REGISTER
ADDRESS
BIT
LABEL
MODE3D
DEFAULT
DESCRIPTION
R16 (10h)
Playback/Record 3D select
0 = 3D selected for Record
1 = 3D selected for Playback
Upper Cut-off frequency
0 = High (2.2kHz at 48kHz sampling)
1 = Low (1.5kHz at 48kHz sampling)
Lower Cut-off frequency
0 = Low (200Hz at 48kHz sampling)
1 = High (500Hz at 48kHz sampling)
Stereo depth
7
0
3D enhance
3DUC
3DLC
6
5
0
0
3DDEPTH
[3:0]
4:1
0000
0000: 0% (minimum 3D effect)
0001: 6.67%
....
1110: 93.3%
1111: 100% (maximum 3D effect)
3D function enable
3DEN
0
0
1: enabled
0: disabled
Table 15 3D Stereo Enhancement Function
When 3D enhancement is enabled (and/or the graphic equaliser for playback) it may be necessary to
attenuate the signal by 6dB to avoid limiting. This is a user selectable function, enabled by setting
ADCDIV2 for the record path and DACDIV2 for the playback path.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R5 (05h)
ADCDIV2
ADC 6dB attenuate enable
0 = disabled (0dB)
8
0
ADC and DAC
control
1 = -6dB enabled
DACDIV2
DAC 6dB attenuate enable
0 = disabled (0dB)
7
0
1 = -6dB enabled
Table 16 ADC and DAC 6dB Attenuation Select
PD, Rev 4.4, August 2012
28
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
