User Manual

DS880F4 133
CS4207
1:0 Read/Write 10b
ADC1 SZCMode[1:0]: Sets the mode by which
analog PGA and digital volume, and muting
changes will be implemented. See “Input Ampli-
fier Capabilities” section on page 55 regarding
digital and analog volume ranges.
‘00’b - Immediate Change: When immediate
change is selected, all level changes will take
effect immediately in one step
‘01’b - Digital Immediate and Analog Zero Cross:
Dictates that signal level changes, both muting
and gain/attenuation, will occur immediately for
digital volume changes, and on a signal zero
crossing for analog volume changes to minimize
audible artifacts. The requested level change will
occur after a timeout period of 1024/Fs (approx.
21 ms @ Fs = 48 kHz) if the signal does not
encounter a zero crossing.
‘10’b - Digital Soft Ramp and Analog Soft Ramp:
Allows level changes, both muting and
gain/attenuation, to be implemented by incre-
mentally ramping at a rate of 1/8 dB per audio
sample period for digital volume changes, and at
a rate of 1 dB per 8 audio sample periods for
analog volume changes. If the analog PGA is
being used for +10 dB “boost” function, or the
Digital Mic is being used, then the digital soft
ramp gain range will be from +12 dB to -51 dB,
and analog soft ramp will not be used.
‘11’b - Digital Soft Ramp and Analog Zero Cross:
Allows level changes, both muting and
gain/attenuation, to be implemented by incre-
mentally ramping at a rate of 1/8 dB per audio
sample period for digital volume changes. Ana-
log volume changes are to be implemented on a
signal zero crossing. The requested level change
will occur after a timeout period of 1024/Fs
(approx. 21 ms @ Fs = 48 kHz) if the signal does
not encounter a zero crossing. If the analog PGA
is being used for +10 dB “boost” function, or the
Digital Mic is being used, then the digital soft
ramp gain range will be from +12 dB to -51 dB
and analog soft ramp will not be used.
Both soft ramp and zero cross are independently
monitored and implemented for each channel.
Bits Type Default Description