Production Data
WM8711BL
AUDIO DATA SAMPLING RATES
The WM8711BL provides for two modes of operation (normal and USB) to generate the required
DAC sampling rates. Normal and USB modes are programmed under software control according to
the table below.
In Normal mode, the user controls the sample rate by using an appropriate MCLK frequency and the
sample rate control register setting. The WM8711BL can support sample rates from 8ks/s up to
96ks/s.
In USB mode, the user must use a fixed MLCK frequency of 12MHz to generate sample rates from
8ks/s to 96ks/s. It is called USB mode since the common USB (Universal Serial Bus) clock is at
12MHz and the WM8711BL can be directly used within such systems. WM8711BL can generate all
the normal audio sample rates from this one Master Clock frequency, removing the need for different
master clocks or PLL circuits.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
0001000
0
USB/
0
Mode Select
NORMAL
BOSR
Sampling
Control
1 = USB mode (250/272fs)
0 = Normal mode (256/384fs)
Base Over-Sampling Rate
1
0
USB Mode
0 = 250fs
1 = 272fs
Normal Mode
96/88.2 kHz
0 = 256fs
0 = 128fs
1 = 384fs
1 = 192fs
5:2
SR[3:0]
0000
DAC sample rate control;
See USB Mode and Normal Mode
Sample Rate sections for operation
Table 10 Sample Rate Control
NORMAL MODE SAMPLE RATES
In normal mode MCLK is set up according to the desired sample rates of the DAC. For DAC sampling
rates of 8, 32, 48 or 96kHz, MCLK frequencies of either 12.288MHz (256fs) or 18.432MHz (384fs)
can be used. DAC sampling rates of 8, 44.1 or 88.2kHz from MCLK frequencies of either
11.2896MHz (256fs) or 16.9344MHz (384fs) can be used.
PD, Rev 4.1, April 2007
27
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
