wm8351 Wolfson Microelectronics plc, wm8351 Datasheet - Page 75

• Manufacturer Part Number: wm8351
• Description: Wolfson Audioplus? Stereo Codec With Power Management
• Manufacturer: Wolfson Microelectronics plc

Production Data
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13.7.1
Table 32 DAC Volume Control
13.7.2
The WM8351 has a soft mute function which, when enabled, gradually attenuates the volume of the
DAC output. When soft mute is disabled, the gain will either gradually ramp back up to the digital
gain setting, or return instantly to the digital gain setting, depending on the DAC_MUTEMODE
register bit.
The DAC is soft-muted by default (DAC_MUTE = 1). To play back an audio signal, this function must
first be disabled by setting DAC_MUTE to 0.
Soft Mute Mode would typically be enabled (DAC_MUTEMODE = 1) when using DAC_MUTE during
playback of audio data so that when DAC_MUTE is subsequently disabled, the sudden volume
increase will not create pop noise by jumping immediately to the previous volume level (e.g.
resuming playback after pausing during a track).
Soft Mute Mode would typically be disabled (DAC_MUTEMODE = 0) when un-muting at the start of a
music file, in order that the first part of the track is not attenuated (e.g. when starting playback of a
new track, or resuming playback after pausing between tracks).
Figure 42 DAC Mute Control
R50 (32h)
DAC Digital
Volume Left
R51 (33h)
DAC Digital
Volume Right
REGISTER
ADDRESS
DAC SOFT MUTE AND SOFT UN-MUTE
DAC PLAYBACK VOLUME CONTROL
BIT
7:0
7:0
8
8
DAC_VU
DACL_VOL
[7:0]
DAC_VU
DACR_VOL
[7:0]
LABEL
1100_0000
1100_0000
DEFAULT
0
0
DAC left and DAC right volume do not
update until a 1 is written to either
DAC_VU register bit.
Left DAC digital volume control:
0000_0000 = Digital mute
0000_0001 = -71.625dB
0000_0010 = -71.25dB
… (0.375dB steps)
1100_000 = 0dB
DAC left and DAC right volume do not
update until a 1 is written to either
DAC_VU register bit.
Right DAC digital volume control:
0000_0000 = Digital mute
0000_0001 = -71.625dB
0000_0010 = -71.25dB
… (0.375dB steps)
1100_000 = 0dB
DAC muting and un-muting using
volume control bits DACL_VOL and
DACR_VOL.
DAC muting and un-muting using soft
mute bit DAC_MUTE. Soft un-mute
not enabled (DAC_MUTEMODE = 0).
DAC muting and un-muting using soft
mute bit DAC_MUTE. Soft un-mute
enabled (DAC_MUTEMODE = 1).
DESCRIPTION
PD, June 2009, Rev 4.1
WM8351
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