WM8986_07 WOLFSON [Wolfson Microelectronics plc], WM8986_07 Datasheet - Page 32

• Manufacturer Part Number: WM8986_07
• Description: Multimedia DAC With Class D Headphone and Line Out
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM8986
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Table 11 DAC Control Register
The digital audio data is converted to oversampled bit streams in the on-chip, true 24-bit digital
interpolation filters. The bitstream data enters the multi-bit, sigma-delta DACs, which convert it to a
high quality analogue audio signal. The multi-bit DAC architecture reduces high frequency noise and
sensitivity to clock jitter. It also uses a Dynamic Element Matching technique for high linearity and
low distortion.
The DAC output phase defaults to non-inverted. Setting DACLPOL will invert the DAC output phase
on the left channel and DACRPOL inverts the phase on the right channel.
AUTO-MUTE
The DAC has an auto-mute 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. Auto-mute can be
disabled using the AMUTE control bit.
DIGITAL HI-FI DAC VOLUME (GAIN) CONTROL
The signal volume from each Hi-Fi DAC can be controlled digitally. The gain range is –127dB to 0dB
in 0.5dB steps. The level of attenuation for an eight-bit code X is given by:
0.5 × (X-255) dB for 1 ≤ X ≤ 255;
Table 12 DAC Digital Volume Control
R10 (0Ah)
DAC Control
R11 (0Bh)
Left DAC
Digital Volume
R12 (0Ch)
Right DAC
Digital Volume
REGISTER
ADDRESS
REGISTER
ADDRESS
7:0
8
7:0
8
BIT
BIT
0
1
2
3
6
DACLVOL
[7:0]
DACVU
DACRVOL
[7:0]
DACVU
DACPOL
DACRPOL
AMUTE
DACOSR128
SOFTMUTE
LABEL
LABEL
MUTE for X = 0
0
0
0
0
0
DEFAULT
11111111
( 0dB )
Not
latched
11111111
( 0dB )
Not
latched
DEFAULT
Left DAC output polarity:
0 = non-inverted
1 = inverted (180 degrees phase shift)
Right DAC output polarity:
0 = non-inverted
1 = inverted (180 degrees phase shift)
Automute enable
0 = Amute disabled
1 = Amute enabled
DAC oversampling rate:
0 = 64x (lowest power)
1 = 128x (best performance)
Softmute enable:
0 = Enabled
1 = Disabled
Left DAC Digital Volume Control
0000 0000 = Digital Mute
0000 0001 = -127dB
0000 0010 = -126.5dB
... 0.5dB steps up to
1111 1111 = 0dB
DAC left and DAC right volume do
not update until a 1 is written to
DACVU (in reg 11 or 12)
Right DAC Digital Volume Control
0000 0000 = Digital Mute
0000 0001 = -127dB
0000 0010 = -126.5dB
... 0.5dB steps up to
1111 1111 = 0dB
DAC left and DAC right volume do
not update until a 1 is written to
DACVU (in reg 11 or 12)
DESCRIPTION
DESCRIPTION
PP, Rev 3.1, February 2007
Pre-Production
32