User Manual

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.

76543210

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

76543210

ALC_ALL Reserved ALCRRATE5 ALCRRATE4 ALCRRATE3 ALCRRATE2 ALCRRATE1 ALCRRATE0

ALC_ALL ALC action:

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].

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