CS42L55 Datasheet, PDF (64/73 Pages) Cirrus Logic – Ultra Low Power, Stereo CODEC w/Class H Headphone Amp

6.31 ALC Threshold (Address 26h)
7
ALCMAX2
6
ALCMAX1
5
ALCMAX0
4
ALCMIN2
3
ALCMIN1
2
ALCMIN0
CS42L55
1
Reserved
0
Reserved
6.31.1 ALC Maximum Threshold
Sets the maximum level, below full-scale, at which to limit and attenuate the input signal at the attack rate
(ALCARATE - “ALC Attack Rate” on page 63).
MAX[2:0]
000
001
010
011
100
101
110
111
Application:
Threshold Setting
0 dB
-3 dB
-6 dB
-9 dB
-12 dB
-18 dB
-24 dB
-30 dB
“Automatic Level Control (ALC)” on page 24
6.31.2 ALC Minimum Threshold
Sets the minimum level at which to disengage the ALC’s attenuation or amplify the input signal at the re-
lease rate (ALCRRATE - “ALC Release Rate” on page 63) until levels lie between the ALCMAX and AL-
CMIN thresholds.
ALCMIN[2:0]
000
001
010
011
100
101
110
111
Application:
Threshold Setting
0 dB
-3 dB
-6 dB
-9 dB
-12 dB
-18 dB
-24 dB
-30 dB
“Automatic Level Control (ALC)” on page 24
Note: This setting is usually set slightly below the ALCMAX threshold.
6.32 Noise Gate Control (Address 27h)
7
NGALL
6
5
4
NG
NG_BOOST
THRESH2
3
THRESH1
2
THRESH0
1
NGDELAY1
0
NGDELAY0
6.32.1 Noise Gate All Channels
Sets which channels are attenuated when clipping on any single channel occurs.
NGALL
0
1
Noise Gate triggered by:
Individual channel; Any channel that falls below the threshold setting triggers the noise gate attenuation for
ONLY that channel.
Both channels A & B; Both channels must fall below the threshold setting for the noise gate attenuation to
take effect.
64
DS773F1