CS42448_07 Datasheet, PDF (48/64 Pages) Cirrus Logic – 108 dB, 192 kHz 6-In, 8-Out CODEC

6.7.2
CS42448
Soft Ramp and Zero Cross Control (ADC_SZC[1:0], DAC_SZC[1:0])
Default = 00
00 - Immediate Change
01 - Zero Cross
10 - Soft Ramp
11 - Soft Ramp on Zero Crossings
Function:
Immediate Change
When Immediate Change is selected, all volume-level changes will take effect immediately in one step.
Zero Cross
Zero Cross Enable dictates that signal level changes, either by gain changes, attenuation changes or mut-
ing, will occur on a signal zero crossing to minimize audible artifacts. The requested level change will oc-
cur after a timeout period between 512 and 1024 sample periods (10.7 ms to 21.3 ms at 48 kHz sample
rate) if the signal does not encounter a zero crossing. The zero cross function is independently monitored
and implemented for each channel.
Soft Ramp
Soft Ramp allows level changes, either by gain changes, attenuation changes or muting, to be implement-
ed by incrementally ramping, in 1/8 dB steps, from the current level to the new level at a rate of 1 dB per
8 left/right clock periods.
Soft Ramp on Zero Crossing
Soft Ramp and Zero Cross Enable dictates that signal level changes, either by gain changes, attenuation
changes or muting, will occur in 1/8 dB steps and be implemented on a signal zero crossing. The 1/8 dB
level change will occur after a timeout period between 512 and 1024 sample periods (10.7 ms to 21.3 ms
at 48 kHz sample rate) if the signal does not encounter a zero crossing. The zero cross function is inde-
pendently monitored and implemented for each channel.
6.7.3
Auto-Mute (AMUTE)
Default = 1
0 - Disabled
1 - Enabled
Function:
The Digital-to-Analog converters of the CS42448 will mute the output following the reception of 8192 con-
secutive audio samples of static 0 or -1. A single sample of non-static data will release the mute. Detection
and muting is done independently for each channel. The quiescent voltage on the output will be retained
and the MUTEC pin will go active during the mute period. The muting function is affected, similar to vol-
ume control changes, by the Soft and Zero Cross bits (SZC[1:0]).
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