wm9081 Wolfson Microelectronics plc, wm9081 Datasheet - Page 44

• Manufacturer Part Number: wm9081
• Description: Mono Dac With 2.6w Class Ab/d Speaker Driver, Dynamic Range Controller And Retune Mobile Parametric Equalizer
• Manufacturer: Wolfson Microelectronics plc

WM9081
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Soft Mute Mode would typically be disabled (DAC_MUTEMODE = 0) when un-muting at the start of
audio playback, in order that the first part of the audio stream is not attenuated.
Figure 31 DAC Mute Control
The volume ramp rate during soft mute and un-mute is controlled by the DAC_MUTERATE bit.
Ramp rates of fs/32 and fs/2 are selectable as shown in Table 24. The ramp rate determines the rate
at which the volume will be increased or decreased. The actual ramp time depends on the extent of
the difference between the muted and un-muted volume settings.
Table 24 DAC Soft-Mute Control
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" section for details of de-emphasis
filter characteristics.
R31 (1Fh)
DAC Digital
2
REGISTER
ADDRESS
10
9
3
BIT
DAC_MUTERATE
DAC_MUTEMODE
DAC_MUTE
LABEL
0
0
1
DEFAULT
DAC Soft Mute Ramp Rate
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)
(Note: ramp rate scales with sample
rate.)
DAC Unmute Ramp select
0 = Disabling soft-mute
(DAC_MUTE=0) will cause the DAC
volume to change immediately to the
DAC_VOL setting.
1 = Disabling soft-mute
(DAC_MUTE=0) will cause the DAC
volume to ramp up gradually to the
DAC_VOL setting.
DAC Soft Mute Control
0 = DAC Un-mute
1 = DAC Mute
DAC muting and un-muting using
volume control bits DAC_VOL
DAC muting and un-muting using soft
mute bit DAC_MUTE.
Soft Mute Mode not enabled
(DAC_MUTEMODE = 0).
DAC muting and un-muting using soft
mute bit DAC_MUTE.
Soft Mute Mode enabled
(DAC_MUTEMODE = 1).
DESCRIPTION
PP, Rev 3.0, April 2009
Pre-Production
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