CS42L55 Datasheet, PDF (65/73 Pages) Cirrus Logic – Ultra Low Power, Stereo CODEC w/Class H Headphone Amp

6.32.2 Noise Gate Enable
Configures the noise gate.
NG
Noise Gate Status
0
Disabled
1
Enabled
CS42L55
6.32.3 Noise Gate Threshold and Boost
THRESH sets the threshold level of the noise gate. Input signals below the threshold level will be attenu-
ated to -96 dB. NG_BOOST configures a +30 dB boost to the threshold settings.
THRESH[2:0]
000
001
010
011
100
101
110
111
Minimum Setting (NG_BOOST = ‘0’b)
-64 dB
-67 dB
-70 dB
-73 dB
-76 dB
-82 dB
Reserved
Reserved
Minimum Setting (NG_BOOST = ‘1’b)
-34 dB
-36 dB
-40 dB
-43 dB
-46 dB
-52 dB
-58 dB
-64 dB
6.32.4 Noise Gate Delay Timing
Sets the delay time before the noise gate attacks.
NGDELAY[1:0]
00
01
10
11
Delay Setting
50 ms
100 ms
150 ms
200 ms
Note: The Noise Gate attack rate is a function of the sampling frequency, Fs, and the DIGSFT (“Digital
Soft Ramp” on page 46) setting unless the disable bit (“ALCx Soft Ramp Disable” on page 65) is enabled.
6.33 ALC and Limiter Soft Ramp, Zero Cross Disables (Address 28h)
7
6
5
4
3
2
1
ALCBSRDIS ALCBZCDIS ALCASRDIS ALCAZCDIS
LIMSRDIS
Reserved
0
Reserved
6.33.1 ALCx Soft Ramp Disable
Configures an override of the analog soft ramp setting.
ALCxSRDIS
0
1
ALC Soft Ramp Disable
OFF; ALC Attack Rate is dictated by the DIGSFT (“Digital Soft Ramp” on page 46) setting
ON; ALC volume changes take effect in one step, regardless of the DIGSFT setting.
6.33.2 ALCx Zero Cross Disable
Configures an override of the analog zero cross setting.
ALCxZCDIS
0
1
ALC Zero Cross Disable
OFF; ALC Attack Rate is dictated by the ANLGZC (“Analog Zero Cross” on page 46) setting
ON; ALC volume changes take effect at any time, regardless of the ANLGZC setting.
DS773F1
65