CS4265_07 Datasheet, PDF (40/56 Pages) Cirrus Logic – 104 dB, 24-Bit, 192 kHz Stereo Audio CODEC

CS4265
6.9 ADC Input Control - Address 09h
7
Reserved
6
Reserved
5
Reserved
4
PGASoft
3
PGAZero
2
Reserved
1
Reserved
0
Select
6.9.1 PGA Soft Ramp or Zero Cross Enable (Bits 4:3)
Function:
Soft Ramp Enable
Soft Ramp allows level changes, both muting and attenuation, to be implemented by incrementally ramp-
ing, 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.
See Table 13.
Zero Cross Enable
Zero Cross Enable dictates that signal-level changes, either by attenuation changes or muting, will occur
on a signal zero crossing to minimize audible artifacts. The requested level change will occur after a time-
out 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. See Table 13.
Soft Ramp and Zero Cross Enable
Soft Ramp and Zero Cross Enable dictate that signal-level changes, either by attenuation changes or mut-
ing, 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 time-out period between 512 and 1024 sample periods (10.7 ms to 21.3 ms at 48 kHz sam-
ple rate) if the signal does not encounter a zero crossing. The zero cross function is independently mon-
itored and implemented for each channel. See Table 13.
6.9.2
PGASoft
0
0
1
1
PGAZeroCross
0
1
0
1
Mode
Changes to affect immediately
Zero Cross enabled
Soft Ramp enabled
Soft Ramp and Zero Cross enabled (default)
Table 13. PGA Soft Cross or Zero Cross Mode Selection
Analog Input Selection (Bit 0)
Function:
These bits are used to select the input source for the PGA and ADC. Please see Table 14.
Select
0
1
PGA/ADC Input
Microphone-Level Input
Line-Level Input
Table 14. Analog Input Selection
6.10 DAC Channel A Volume Control - Address 0Ah
See 6.11 DAC Channel B Volume Control - Address 0Bh.
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