WM8742 View Datasheet(PDF) - Cirrus Logic
Part Name
Description
MFG CO.
'WM8742' PDF : 65 Pages View PDF
Production Data
WM8742
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
R5
Format Control
05h
4
LRP
Table 17 LRCLK Polarity Control
DEFAULT
0
DESCRIPTION
LRCLK polarity select:
0 = normal LRCLK polarity
1 = inverted LRCLK polarity
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
R5
4
Format Control
05h
Table 18 DSP Format Control
LABEL
LRP
DEFAULT
0
DESCRIPTION
DSP format select:
0 = DSP mode A
1 = DSP mode B
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
R5
5
Format Control
05h
Table 19 BCLK Polarity Control
LABEL
BCP
DEFAULT
0
DESCRIPTION
BCLK / DSD64CLK polarity select:
0 = normal polarity
1 = inverted polarity
OVERSAMPLING RATE CONTROL
The user has control of the oversampling ratio of the WM8742, 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 WM8742, the user must ensure the correct value of OSR[1:0] is set at all times.
REGISTER ADDRESS BIT LABEL
R7
[6:5] OSR[1:0]
Mode Control 1
07h
Table 20 Oversampling Rate Control
DEFAULT
00
DESCRIPTION
Oversampling Rate Selection
00 = Low rate (32/44.1/48kHz)
01 = Medium rate (96kHz)
10 = High rate (192kHz)
11 = Unused
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PD, Rev 4.3, February 2013
29
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