Pre-Production
WM8985
3D STEREO ENHANCEMENT
The WM8985 has a digital 3D enhancement option to increase the perceived separation between the
left and right channels. Selection of 3D for record or playback is controlled by register bit
EQ3DMODE. Switching this bit from record to playback or from playback to record may only be done
when both ADCs and both DACs are disabled.
The DEPTH3D setting controls the degree of stereo expansion.
REGISTER
ADDRESS
BIT
LABEL
DEPTH3D
DEFAULT
DESCRIPTION
Stereo depth
R41 (29h)
3D Control
3:0
0000
0000 = Disabled
0001 = 6.67%
0010 = 13.3%
0011 = 20%
0100 = 26.7%
0101 = 33.3%
0110 = 40%
0111 = 46.6%
1000 = 53.3%
1001 = 60%
1010 = 66.7%
1011 = 73.3%
1100 = 80%
1101 = 86.7%
1110 = 93.3%
1111 = 100% (maximum 3D effect)
Table 32 3D Stereo Enhancement Function
Note: When 3D enhancement is used, it may be necessary to attenuate the signal by 6dB to avoid
limiting.
ANALOGUE OUTPUTS
The WM8985 has three sets of stereo analogue outputs. These are:
•
•
LOUT1 and ROUT1 which are normally used to drive a headphone load.
LOUT2 and ROUT2 – which can be used as class D or class AB headphone
drivers.
•
OUT3 and OUT4 – can be configured as a stereo line out (OUT3 is left output and
OUT4 is right output) or a differential output. OUT4 can also be used to provide a
mono mix of left and right channels.
The outputs LOUT2 and ROUT2 are powered from AVDD2 and are capable of driving a 1V rms
signal (AVDD1/3.3).
LOUT1, ROUT1, OUT3 and OUT4 are powered from AVDD1
LOUT1, ROUT1, LOUT2 and ROUT2 have individual analogue volume PGAs with -57dB to +6dB
gain ranges.
There are four output mixers in the output signal path, the left and right channel mixers which control
the signals to headphone (and optionally the line outputs) and also dedicated OUT3 and OUT4
mixers.
PP, Rev 3.4, October 2006
61
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
