Cirrus Logic CS42L56 - Manual (Page 78)

78 DS851F2
CS42L56
6.29 ALC Enable & Attack Rate (Address 22h)
6.29.1 ALCx
Configures the automatic level controller (ALC).
Notes:
1. The ALC should only be configured while the power down bit (
“Power Down” on page 59 ) is enabled.
2. The ALC is not available in passthrough mode.
6.29.2 ALC Attack Rate
Sets the rate at which the ALC applies analog and/or digital attenuation from levels above the AMAX[2:0]
threshold (
“ALC Maximum Threshold” on page 80 ).
Note: The ALC attack rate is user-selectable but is also a function of the sampling frequency, Fs, the
ANLGZCx ( “Analog Zero Cross” on page 64 ) and the DIGSFT ( “Digital Soft Ramp” on page 64 ) setting
unless the respective disable bit ( “ALCx Soft Ramp Disable” on page 82 or “ALCx Zero Cross Disable” on
page 82 ) is enabled.
6.30 ALC Release Rate (Address 23h)
6.30.1 ALC Limit All Channels
Sets how channels are attenuated when the ALC is enabled.
Note: This function should only be used when the ALC for both channels is enabled.
7 6 5 4 3 2 1 0
ALCB ALCA ALCARATE5 AALCRATE4 ALCARATE3 ALCARATE2 ALCARATE1 ALCARATE0
ALC ALC Status
0 Disabled
1 Enabled
Application: “Automatic Level Control (ALC)” on page 35
ALCARATE[5:0] Attack Time
00 0000 Fastest Attack
··· ···
11 1111 Slowest Attack
Application: “Automatic Level Control (ALC)” on page 35
7 6 5 4 3 2 1 0
ALC_ALL Reserved ALCRRATE5 ALCRRATE4 ALCRRATE3 ALCRRATE2 ALCRRATE1 ALCRRATE0
ALC_ALL ALC action:
0
Apply the necessary attenuation on a specific channel only when the signal amplitudes on that specific chan-
nel rises above ALCMAX[2:0].
Remove attenuation on a specific channel only when the signal amplitude on that specific channel falls below
ALCMIN[2:0].
1
Apply the necessary attenuation on BOTH channels when the signal amplitudes on any ONE channel rises
above ALCMAX[2:0].
Remove attenuation on BOTH channels only when the signal amplitude on BOTH channels fall below ALC-
MIN[2:0].
Application: “Automatic Level Control (ALC)” on page 35