wm8940gefl-v Wolfson Microelectronics plc, wm8940gefl-v Datasheet - Page 42

• Manufacturer Part Number: wm8940gefl-v
• Description: Mono Codec With Speaker Driver
• Manufacturer: Wolfson Microelectronics plc

WM8940
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HI-FI DIGITAL TO ANALOGUE CONVERTER (DAC)
Table 30 DAC Enable
Table 31 DAC Control Register
AUTOMUTE
Table 32 DAC Auto Mute Control Register
The DAC is enabled by the DACEN register bit.
The WM8940 also has a Soft Mute function, which gradually attenuates the volume of the digital
signal to zero. When removed, the gain will step back up to the digital gain setting. This function is
disabled by default. To play back an audio signal, it must first be disabled by setting the DACMU bit
to zero.
The digital audio data is converted to over sampled bit streams in the on-chip, true 24-bit digital
interpolation filters. The bit stream data enters a multi-bit, sigma-delta DAC, which converts it to a
high quality analogue audio signal. The multi-bit DAC architecture reduces high frequency noise and
sensitivity to clock jitter.
The DAC output defaults to non-inverted. Setting DACPOL will invert the DAC output phase.
The DAC has an automute function which applies an analogue mute when 1024 consecutive zeros
are detected. The mute is released as soon as a non-zero sample is detected. Automute can be
enabled using the AMUTE control bit.
R10
DAC Control
R10
DAC Control
R3
Power
Management 3
REGISTER
REGISTER
ADDRESS
ADDRESS
REGISTER
ADDRESS
BIT
BIT
0
6
2
BIT
DACMU
AMUTE
DACEN
LABEL
LABEL
LABEL
0
DEFAULT
0
0
DEFAULT
DEFAULT
DAC enable
0 = DAC disabled
1 = DAC enabled
DAC soft mute enable
0 = DACMU disabled
1 = DACMU enabled
DAC auto mute enable
0 = auto mute disabled
1 = auto mute enabled
DESCRIPTION
DESCRIPTION
DESCRIPTION
PD, Rev 4.2, April 2008
Production Data
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