WM8711BL
Production Data
AUDIO SIGNAL PATH
DAC FILTERS
The DAC filters perform true 24 bit signal processing to convert the incoming digital audio data from
the digital audio interface at the specified sample rate to multi-bit oversampled data for processing by
the analogue DAC. Figure 6 illustrates the DAC digital filter path.
FROM DIGITAL
DIGITAL
TO LINE
DIGITAL
MUTE
INTERPOLATION
AUDIO
INTERFACE
DE_EMPHASIS
OUTPUTS
FILTER
DEEMP
DACMU
Figure 6 DAC Filter Schematic
The DAC digital filter can apply digital de-emphasis under software control, as shown in Table 2. The
DAC can also perform a soft mute where the audio data is digitally brought to a mute level. This
removes any abrupt step changes in the audio that might otherwise result in audible clicks in the
audio outputs.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
0000101
2:1
DEEMP[1:0]
00
De-emphasis Control
(Digital)
Digital Audio
Path Control
11 = 48kHz
10 = 44.1kHz
01 = 32kHz
00 = Disable
3
DACMU
1
DAC Soft Mute Control
(Digital)
1 = Enable soft mute
0 = Disable soft mute
Note 1
Table 2 DAC Software ControlNote 1
Not valid when SR[3:0] = 1111 or 0111.
To ensure correct DACMU operation at fs = 88.2kHz, set SR[3:0] = 1000.
To ensure correct DACMU operation at fs = 96kHz, set SR[3:0] = 0000.
PD, Rev 4.2, December 2011
1444
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
