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Production Data
WM8978
w
PD, Rev 4.5, October 2011
31
Figure 16 ADC Digital Filter Path
The ADCs are enabled by the ADCENL/R register bit.
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
R2
Power
management 2
0
ADCENL
0
Enable ADC left channel:
0 = ADC disabled
1 = ADC enabled
1
ADCENR
0
Enable ADC right channel:
0 = ADC disabled
1 = ADC enabled
Table 12 ADC Enable Control
The polarity of the output signal can also be changed under software control using the
ADCLPOL/ADCRPOL register bit. The oversampling rate of the ADC can be adjusted using the
ADCOSR register bit. With ADCOSR=0 the oversample rate is 64x which gives lowest power
operation and when ADCOSR=1 the oversample rate is 128x which gives best performance.
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
R14
ADC Control
0
ADCLPOL
0
ADC left channel polarity adjust:
0=normal
1=inverted
1
ADCRPOL
0
ADC right channel polarity adjust:
0=normal
1=inverted
3
ADCOSR
0
ADC oversample rate select:
0=64x (lower power)
1=128x (best performance)
Table 13 ADC Control
SELECTABLE HIGH PASS FILTER
A selectable high pass filter is provided. To disable this filter set HPFEN=0. The filter has two
modes controlled by HPFAPP. In Audio Mode (HPFAPP=0) the filter is first order, with a cut-off
frequency of 3.7Hz. In Application Mode (HPFAPP=1) the filter is second order, with a cut-off
frequency selectable via the HPFCUT register. The cut-off frequencies when HPFAPP=1 are shown
in Table 15.
Содержание WM8978
Страница 11: ...Production Data WM8978 w PD Rev 4 5 October 2011 11 SPEAKER OUTPUT THD VERSUS POWER...
Страница 14: ...WM8978 Production Data w PD Rev 4 5 October 2011 14 AUDIO PATHS OVERVIEW...
Страница 46: ...WM8978 Production Data w PD Rev 4 5 October 2011 46 Figure 22 ALC Operation Above Noise Gate Threshold...
Страница 55: ...Production Data WM8978 w PD Rev 4 5 October 2011 55 Figure 26 Left Right Output Channel Mixers...
Страница 60: ...WM8978 Production Data w PD Rev 4 5 October 2011 60 Figure 29 Speaker Outputs LOUT2 and ROUT2...