WM8741
Production Data
DIGITAL FILTER SELECTION
The WM8741 includes a wide range of digital filters. A limited set of these can be selected in
hardware control mode as listed in Table 50. Full details of each digital filter response can be found
in section PCM Digital Filter Selection, from page 37.
PIN
NAME
FSEL/
DINR
DESCRIPTION
4
Digital filter selection
(32/44.1/48kHz):
0 = Response 1
1 = Response 5
Z = Response 4
Digital filter selection (88.2/96kHz
and 176.4/192kHz):
0 = Response 1
1 = Response 3
Z = Response 2
Table 50 FSEL/DINR Hardware Control Pin Function
There is no choice of digital filters in DSD Direct mode – only the very minimal filtering described in
Figure 72 and Figure 73 is available.
DIFFERENTIAL MONO MODE
If DIFFHW (pin 6) is held to Logic 1, hardware controlled differential mono mode is selected. This
overrides any other control pin or register bit. Differential mono mode allows the user to build a dual
differential stereo DAC implementation with higher performance and differential output. DIFFHW is
used in conjunction with MODE/LRSEL (pin 24) to define a ‘left’ or ‘right’ DAC as shown in Table 51.
PIN NUMBER
NAME
6
24
DESCRIPTION
DIFFHW
MODE/LRSEL
0
0
0
1
0
Z
1
0
Hardware control (stereo)
2-wire Software Control
3-wire software control)
Mono Left – differential outputs
VOUTLP = left channel
VOUTLN = left channel inverted
VOUTRP = left channel inverted
VOUTRN = left channel
1
1
Mono right – differential outputs
VOUTLP = right channel inverted
VOUTLN = right channel
VOUTRP = right channel
VOUTRN = right channel inverted
Table 51 DIFFHW and MODE/LRSEL Hardware Control Pin Functions
Differential mono mode is available for all PCM hardware controlled modes and DSD Direct hardware
mode.
PD, Rev 4.2, October 2009
42
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
