Pre-Production
WM8904
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R33 (21h)
DAC Soft Mute Ramp Rate
10
DAC_MUTERA
TE
0
DAC Digital 1
0 = Fast ramp (fs/2, maximum ramp
time is 10.7ms at fs=48k)
1 = Slow ramp (fs/32, maximum ramp
time is 171ms at fs=48k)
DAC Soft Mute Mode
9
DAC_UNMUTE
_RAMP
0
0 = Disabling soft-mute
(DAC_MUTE=0) will cause the DAC
volume to change immediately to
DACL_VOL and DACR_VOL settings
1 = Disabling soft-mute
(DAC_MUTE=0) will cause the DAC
volume to ramp up gradually to the
DACL_VOL and DACR_VOL settings
DAC Soft Mute Control
0 = DAC Un-mute
1 = DAC Mute
3
DAC_MUTE
1
Table 35 DAC Soft-Mute Control
DAC MONO MIX
A DAC digital mono-mix mode can be enabled using the DAC_MONO register bit. This mono mix will
be output on whichever DAC is enabled. To prevent clipping, a -6dB attenuation is automatically
applied to the mono mix.
The mono mix is only supported when one or other DAC is disabled. When the mono mix is selected,
then the mono mix is output on the enabled DAC only; there is no output from the disabled DAC. If
DACL_ENA and DACR_ENA are both set, then stereo operation applies.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R33 (21h)
DAC Mono Mix
12
DAC_MONO
0
DAC Digital 1
0 = Stereo
1 = Mono (Mono mix output on
enabled DAC)
Table 36 DAC Mono Mix
DAC DE-EMPHASIS
Digital de-emphasis can be applied to the DAC playback data (e.g. when the data comes from a CD
with pre-emphasis used in the recording). De-emphasis filtering is available for sample rates of
48kHz, 44.1kHz and 32kHz. See “Digital Filter Characteristics” for details of de-emphasis filter
characteristics.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R33 (21h)
DAC Digital 1
DAC De-Emphasis Control
00 = No de-emphasis
2:1
DEEMPH [1:0]
00
01 = 32kHz sample rate
10 = 44.1kHz sample rate
11 = 48kHz sample rate
Table 37 DAC De-Emphasis Control
PP, Rev 3.3, September 2012
69
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