Cirrus Logic CS4385A - Manual (Page 40)

40 DS837F2
CS4385A
7.4.2 Direct DSD Conversion (DIR_DSD)
Function:
When set to 0 (default), DSD input data is sent to the DSD processor for filtering and volume control func-
tions.
When set to 1, DSD input data is sent directly to the switched capacitor DACs for a pure DSD conversion.
In this mode, the full-scale DSD and PCM levels will not be matched (see
Section 1 ), the dynamic range
performance may be reduced, the volume control is inactive, and the 50 kHz low-pass filter is not available
(see
Section 1 for filter specifications).
7.4.3 Static DSD Detect (STATIC_DSD)
Function:
When set to 1 (default), the DSD processor checks for 28 consecutive zeroes or ones and, if detected,
sends a mute signal to the DACs. The MUTEC pins will eventually go active according to the DAMUTE
register.
When set to 0, this function is disabled.
7.4.4 Invalid DSD Detect (INVALID_DSD)
Function:
When set to 1, the DSD processor checks for greater than 24 out of 28 bits of the same value and, if de-
tected, will attenuate the data sent to the DACs. The MUTEC pins go active according to the DAMUTE
register.
When set to 0 (default), this function is disabled.
7.4.5 DSD Phase Modulation Mode Select (DSD_PM_MODE)
Function:
When set to 0 (default), the 128Fs (BCKA) clock should be input to DSD_SCLK for Phase Modulation
Mode. (See
Figure 21 on page 28 )
When set to 1, the 64Fs (BCKD) clock should be input to DSD_SCLK for Phase Modulation Mode.
7.4.6 DSD Phase Modulation Mode Enable (DSD_PM_EN)
Function:
When set to 1, DSD phase modulation input mode is enabled, and the DSD_PM_MODE bit should be set
accordingly.
When set to 0 (default), this function is disabled (DSD normal mode).
1 0 0 128x oversampled DSD data with a 2x MCLK to DSD data rate
1 0 1 128x oversampled DSD data with a 3x MCLK to DSD data rate
1 1 0 128x oversampled DSD data with a 4x MCLK to DSD data rate
1 1 1 128x oversampled DSD data with a 6x MCLK to DSD data rate
DIF2 DIF1 DIFO DESCRIPTION
Table 8. Digital Interface Formats - DSD Mode