Owner's manual

DS782F2 33
CS4349
8.5 Channel A & B Volume Control - Register 05h & 06h
Digital Volume Control (VOL[7:0]) 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 16. 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.
8.6 Ramp and Filter Control - Register 07h
8.6.1 Soft Ramp and Zero Cross Control (SZC[1:0]) Bits 7-6
Default = 10
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.
76543210
VOL7 VOL6 VOL5 VOL4 VOL3 VOL2 VOL1 VOL0
00000000
Table 16. Example Digital Volume Settings
Binary Code Decimal Value Volume Setting
00000000 0 0 dB
00000001 1 -0.5 dB
00000110 6 -3.0 dB
11111111 255 -127.5 dB
76543210
SZC1 SZC0 RMP_UP RMP_DN Reserved FILT_SEL Reserved Reserved
10110001
SZC1 SZC0 Description
0 0 Immediate Change
0 1 Zero Cross
1 0 Soft Ramp
1 1 Soft Ramp on Zero Crossings