Cirrus Logic CS42L52 - Manual (Page 49)

DS680F2 49
CS42L52
3/1/13
6.8.2 PGA Input Mapping
Selects one or sums/mixes the analog input signal into the PGA. Each bit of the PGAx_SEL[5:1] word
corresponds to individual channels (i.e. PGAx_SEL1 selects AIN1x, PGAx_SEL2 selects AIN2x, etc.).
6.9 Analog and HPF Control (Address 0Ah)
6.9.1 ADCx High-Pass Filter
Configures the internal high-pass filter after ADCx.
6.9.2 ADCx High-Pass Filter Freeze
Configures the high pass filter’s digital DC subtraction and/or calibration after ADCx.
6.9.3 Ch. x Analog Soft Ramp
Configures an incremental volume ramp from the current level to the new level at the specified rate.
6.9.4 Ch. x Analog Zero Cross
Configures when the signal level changes occur for the analog volume controls.
Note: If the signal does not encounter a zero crossing, the requested volume change will occur after a
timeout period of 1024 sample periods (approximately 10.7 ms at 48 kHz sample rate).
PGAxSEL[5:1] Selected Input to PGAx (Examples)
00000 No inputs selected
00001 AIN1x
00010 AIN2x
00100 AIN3x
01000 AIN4x
10000
MICx; for single-ended MIC inputs, use MICxSEL ( “MIC x Select” on page 55 ) to select MIC 1 or MIC 2; for
differential MIC inputs, enable MICxCFG ( “MICx Configuration” on page 55 )
10001 MICx + AIN1x
10011 MICx + AIN1x + AIN2x
Application: “Analog Inputs” on page 25
Note: Table does not show all possible combinations.
7 6 5 4 3 2 1 0
HPFB HPFRZB HPFA HPFRZA ANLGSFTB ANLGZCB ANLGSFTA ANLGZCA
HPFx High Pass Filter Status
0 Disabled
1 Enabled
HPFRZx High Pass Filter Digital Subtraction
0 Continuous DC Subtraction
1 Frozen DC Subtraction
ANLGSFTx Volume Changes Affected Analog Volume Controls
0 Do not occur with a soft ramp MICxGAIN[4:0] ( “MICx Gain” on page 55 ), PGAxVOL[5:0] ( “PGAx Volume”
on page 56 ), and PASSxVOL[7:0] ( “Passthrough x Volume” on page 57 ) 1 Occur with a soft ramp
Ramp Rate: 1/2 dB every 16 LRCK cycles
ANLGZCx Volume Changes Affected Analog Volume Controls
0
Do not occur on a zero cross-
ing
MICxGAIN[4:0] ( “MICx Gain” on page 55 ), PGAxVOL[5:0] ( “PGAx Volume”
on page 56 ), and PASSxVOL[7:0] ( “Passthrough x Volume” on page 57 )
1 Occur on a zero crossing