Production Data
WM8741
LRCLK POLARITY
In left justified, right justified or I2S modes, the LRP register bit controls the polarity of LRCLK. If this
bit is set high, the expected polarity of LRCLK will be the opposite of that shown in Figure 14, Figure
15 and Figure 16. If this feature is used as a means of swapping the left and right channels, a 1
sample phase difference will be introduced.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
LRCLK polarity select:
R5
Format Control
05h
4
LRP
0
0 = normal LRCLK polarity
1 = inverted LRCLK polarity
Table 17 LRCLK Polarity Control
In DSP modes, the LRP register bit is used to select between DSP mode A and B (see Figure 17 and
Figure 18).
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
DSP format select:
R5
Format Control
05h
4
LRP
0
0 = DSP mode A
1 = DSP mode B
Table 18 DSP Format Control
BCLK / DSDCLK64 POLARITY
In PCM mode, LRCLK and DIN are sampled on the rising edge of BCLK by default, and should
ideally change on the falling edge. Data sources which change LRCLK and DIN on the rising edge of
BCLK can be supported by setting the BCP register bit. Setting BCP to 1 inverts the polarity of
BCLK to the inverse of that shown in Figure 14, Figure 15, Figure 16, Figure 17 and Figure 18.
In DSD mode, DSDL and DSDR inputs are sampled a fixed delay after a falling 64fs clock edge.
When BCP is set in DSD mode, DSDL and DSDR are sampled a fixed delay after a rising 64fs clock
edge.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
BCLK / DSD64CLK polarity select:
0 = normal polarity
R5
Format Control
05h
5
BCP
0
1 = inverted polarity
Table 19 BCLK Polarity Control
OVERSAMPLING RATE CONTROL
The user has control of the oversampling ratio of the WM8741, and can set to the device to operate
in low, medium or high rate modes. For correct operation of the digital filtering and other processing
on the WM8741, the user must ensure the correct value of OSR[1:0] is set at all times.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Oversampling Rate Selection
00 = Low rate (32/44.1/48kHz)
01 = Medium rate (96kHz)
10 = High rate (192kHz)
11 = Unused
R7
Mode Control 1
07h
[6:5] OSR[1:0]
00
Table 20 Oversampling Rate Control
PD, Rev 4.2, October 2009
29
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
