Cirrus Logic CS4398 - Manual (Page 36)

36 DS568F1
CS4398
7.7.2 Soft Volume Ramp-up after Error (RMP_UP) Bit 5
Function:
An un-mute will be performed after executing an LRCK/MCLK ratio change or error, and after changing
the Functional Mode.
When set to 1 (default), this un-mute is effected, similar to attenuation changes, by the Soft and Zero
Cross bits in the Volume and Mixing Control register.
When set to 0, an immediate un-mute is performed in these instances.
Notes: For best results, it is recommended that this feature be used in conjunction with the RMP_DN bit.
7.7.3 Soft Ramp-down before Filter Mode Change (RMP_DN) Bit 4
Function:
If either the FILT_SEL or DEM bits are changed the DAC will stop conversion for a period of time to
change its filter values. This bit selects how the data is effected prior to and after the change of the filter
values.
When set to 1 (default), a mute will be performed prior to executing a filter mode change and an un-mute
will be performed after executing the filter mode change. This mute and un-mute are effected, similar to
attenuation changes, by the Soft and Zero Cross bits in the Volume and Mixing Control register.
When set to 0, an immediate mute is performed prior to executing a filter mode change.
Notes: For best results, it is recommended that this feature be used in conjunction with the RMP_UP bit.
7.7.4 Interpolation Filter Select (FILT_SEL) Bit 2
Function:
When set to 0 (default), the Interpolation Filter has a fast roll off.
When set to 1, the Interpolation Filter has a slow roll off.
The specifications for each filter can be found in the Analog characteristics table, and response plots can
be found in figures 20 to 43 found in the “Appendix” on page 41.
7.7.5 Direct DSD Conversion (DIR_DSD) Bit 0
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 2), the dynamic range
performance may be reduced, the volume control is inactive, and the 50 kHz low pass filter is not available
(see Section 2 for filter specifications).