WM8786
Pre-Production
AUDIO INTERFACE CONTROL
AUDIO INTERFACE CONTROL
The audio interface is controlled using the AUDIOF0 and AUDIOF1 pins. Dynamically changing the
audio format may cause erroneous operation of the interfaces and is therefore not recommended.
All ADC data is signed 2’s complement. The length of the digital audio data is always 24 bits.
AUDIOF1 PIN STATUS
AUDIOF0 PIN STATUS
AUDIO INTERFACE
FORMAT
Low
Low
High
High
Low
High
Low
High
24-bit right justified
24-bit left justified
24-bit I2S
24-bit DSP
Table 3 Audio Interface Format Selection
OVERSAMPLING RATIOS AND SIGMA-DELTA MODULATOR FREQUENCY
For correct operation of the device and optimal performance, the user must select the appropriate
ADC modulator oversampling ratio. The oversampling ratio is selected using the OSR0 and OSR1
pins.
OSR1 PIN STATUS
OSR0 PIN STATUS
OVERSAMPLING RATIO
CONTROL
Low
Low
High
High
Low
High
Low
High
Single Rate (128fs)
Dual Rate (64fs)
Quad Rate (32fs)
Not Valid
Table 4 Oversampling Ratio Selection
The WM8786 can operate at sample rates from 8kHz to 192kHz. The WM8786 uses a sigma-delta
modulator that operates at frequencies between 1.024MHz and 6.144MHz
SAMPLING RATE
(LRCLK)
OVERSAMPLING RATIO
SIGMA-DELTA
MODULATOR
FREQUENCY (MHZ)
8kHz
32kHz
44.1kHz
48kHz
96kHz
192kHz
Single Rate (128fs)
Single Rate (128fs)
Single Rate (128fs)
Single Rate (128fs)
Dual Rate (64fs)
1.024
4.096
5.6448
6.144
6.144
6.144
Quad Rate (32fs)
Table 5 Sigma-delta Modulator Frequency
PP Rev 3.0 December 2005
18
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
