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WM8775
DIGITAL AUDIO INTERFACE
MASTER AND SLAVE MODES
The audio interface operates in either Slave or Master mode, selectable using the MS control bit. In
both Master and Slave modes ADCDAT is always an output. The default is Slave mode.
In Slave mode (MS=0) ADCLRC and BCLK are inputs to the WM8775 (Figure 10). ADCLRC is
sampled by the WM8775 on the rising edge of BCLK. ADC data is output on DOUT and changes on
the falling edge of BCLK. By setting control bit BCLKINV the polarity of BCLK may be reversed so
that ADCLRC is sampled on the falling edge of BCLK and DOUT changes on the rising edge of
BCLK.
BCLK
DVD
Controller
WM8775
ADC
ADCLRC
DOUT
Figure 10 Slave Mode
In Master mode (MS=1) ADCLRC and BCLK are outputs from the WM8775 (Figure 11). ADCLRC
and BITCLK are generated by the WM8775. ADCDAT is output on DOUT and changes on the falling
edge of BCLK. By setting control bit BCLKINV, the polarity of BCLK may be reversed so that DOUT
changes on the rising edge of BCLK.
BCLK
DVD
Controller
WM8775
ADC
ADCLRC
DOUT
Figure 11 Master Mode
PP Rev 1.8, June 2004
15
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
