CS4351_05 Datasheet, PDF (28/37 Pages) Cirrus Logic – 192 kHz Stereo DAC with 2 Vrms Line Out

6.5.1
CS4351
Digital Volume Control (VOL7:0) Bits 7-0
Default = 00h (0 dB)
Function:
The Digital Volume Control registers allow independent control of the signal levels in 1/2 dB increments
from 0 to -127.5 dB. Volume settings are decoded as shown in Table 9. The volume changes are imple-
mented as dictated by the Soft and Zero Cross bits in the Power and Muting Control register.
The actual attenuation is determined by taking the decimal value of the volume register and multiplying
by 6.02/12.
Binary Code
00000000
00000001
00000110
11111111
Decimal Value
0
1
6
255
Volume Setting
0 dB
-0.5 dB
-3.0 dB
-127.5 dB
Table 9. Example Digital Volume Settings
6.6 Ramp and Filter Control - Register 07h
7
SZC1
1
6
SZC0
0
5
RMP_UP
1
4
RMP_DN
1
3
Reserved
0
2
FILT_SEL
0
1
Reserved
0
0
Reserved
1
6.6.1
Soft Ramp and Zero Cross Control (SZC1:0) Bits 7-6
Default = 10
SZC1 SZC0
0
0
0
1
1
0
1
1
Description
Immediate Change
Zero Cross
Soft Ramp
Soft Ramp on Zero Crossings
Function:
Immediate Change
When Immediate Change is selected all level changes will take effect immediately in one step.
Zero Cross
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.
Soft Ramp PCM
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.
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DS566F1