Minimum And Maximum Gain - Cirrus Logic WM8940 Manual

Rev 4.4

MINIMUM AND MAXIMUM GAIN

The ALCMIN and ALCMAX register bits set the minimum/maximum gain value that the PGA can be
set to whilst under the control of the ALC. This has no effect on the PGA when ALC is not enabled.
REGISTER BIT LABEL
ADDRESS
R32 5:3 ALCMAX
ALC Control 1
2:0 ALCMIN
Table 23 ALC Max/Min Gain
In normal mode, ALCMAX sets the maximum boost which can be applied to the signal. In limiter
mode, ALCMAX will normally have no effect (assuming the starting gain value is less than the
maximum gain specified by ALCMAX) because the maximum gain is set at the starting gain level.
ALCMIN sets the minimum gain value which can be applied to the signal.
PGA Gain = 111111 (+35.25dB)
Whole PGA gain range
PGA Gain = 000000 (-12dB)
Figure 14 ALC Min/Max Gain
ALCMAX Maximum Gain (dB)
111 35.25
110 29.25
101 23.25
100 17.25
011 11.25
010 5.25
001 -0.75
000 -6.75
Table 24 ALC Max Gain Values
DEFAULT DESCRIPTION
111 Set Maximum Gain of PGA
000 Set minimum gain of PGA
ALCMAX
ALC operating range
ALCMIN
WM8940
35