CS4265_07 Datasheet, PDF (41/56 Pages) Cirrus Logic – 104 dB, 24-Bit, 192 kHz Stereo Audio CODEC

CS4265
6.11 DAC Channel B Volume Control - Address 0Bh
7
6
5
4
3
2
1
0
Vol7
Vol6
Vol5
Vol4
Vol3
Vol2
Vol1
Vol0
6.11.1 Volume Control (Bits 7:0)
Function:
The digital volume control allows the user to attenuate the signal in 0.5 dB increments from 0 to -127 dB.
The Vol0 bit activates a 0.5 dB attenuation when set, and no attenuation when cleared. The Vol[7:1] bits
activate attenuation equal to their decimal equivalent (in dB). Example volume settings are decoded as
shown in Table 15. The volume changes are implemented as dictated by the DACSoft and DACZero-
Cross bits in the DAC Control 2 register (see Section 6.12.1).
Binary Code
Volume Setting
00000000
0 dB
00000001
-0.5 dB
00101000
-20 dB
00101001
-20.5 dB
11111110
-127 dB
11111111
-127.5 dB
Table 15. Digital Volume Control Example Settings
6.12 DAC Control 2 - Address 0Ch
7
DACSoft
6
DACZero
5
InvertDAC
4
Reserved
3
Reserved
2
Reserved
1
Reserved
0
Reserved
6.12.1 DAC Soft Ramp or Zero Cross Enable (Bits 7:6)
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 16.
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 16.
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-
DS657F2
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