PCM1738_15 Datasheet, PDF (35/47 Pages) Texas Instruments – Audio-Stereo Digital-to-Analog Converter

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PCM1738
SBAS174C – FEBRUARY 2002 – REVISED FEBRUARY 2007
OS[1:0]
ZFGx
Delta-Sigma Oversampling Rate Selection
These bits are available for read/write.
Default Value: 00
OS[1:0] Operation Speed Select
00
8 × f_WDCK (default)
01 Reserved
10
16 × f_WDCK
11
4 × f_WDCK
The effective oversampling rate is determined by the oversampling performed by both the external
digital filter and the delta-sigma modulator. For example, if the external digital filter is 8×
oversampling, and the user selects OS[1:0] = 0, then the delta-sigma modulator oversamples by 8×,
resulting in an effective oversampling rate of 64×.
Zero-Detect Flag
where x = L or R, corresponding to the DAC output channel.
These bits are available only for read-back.
Default value: 00
ZFGx = 0 Not ZERO
ZFGx = 1 ZERO detected
When the PCM1738 detects that audio input data is continuously zero for 1024 WDCKs, the ZFGx
bit is set to 1 for the corresponding channel(s). Zero-detect flags are also available at ZEROL (pin
2) and ZEROR (pin 3).
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