WM8591
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Table 5 shows the typical system clock frequencies for ADC operation at both 128 times
oversampling rate (ADCOSR=0) and 64 times oversampling rate (ADCOSR=1), and DAC operation
at 128 times oversampling rate (DACOSR=0). Table 6 shows typical system clock frequencies for
DAC operation at 64 times oversampling rate (DACOSR =1).
SAMPLING
RATE
System Clock Frequency (MHz)
256fs
384fs
512fs
768fs
1152fs
(ADCLRC/
DACLRC)
32kHz
(DAC only)
8.192
11.2896
12.288
24.576
12.288
16.9340
18.432
36.864
16.384
22.5792
24.576
24.576
33.8688
36.864
36.864
44.1kHz
48kHz
Unavailable
Unavailable
96kHz
Unavailable Unavailable Unavailable
Table 5 ADC and DAC System Clock Frequencies Versus Sampling Rate
(ADC operation at either 128 times oversampling rate (ADCOSR=0) or 64 times oversampling
rate (ADCOSR=1), DAC operation at 128 times oversampling rate, DACOSR=0)
SAMPLING
RATE
System Clock Frequency (MHz)
128fs
192fs
(DACLRC)
96kHz
12.288
24.576
18.432
36.864
192kHz
Table 6 DAC System Clock Frequencies Versus Sampling Rate at 64 Times
Oversampling Rate (DACOSR=1)
In Master mode DACBCLK, ADCBCLK, DACLRC and ADCLRC are generated by the WM8591. The
frequencies of ADCLRC and DACLRC are set by setting the required ratio of DACMCLK to DACLRC
and ADCMCLK to ADCLRC using the DACRATE and ADCRATE control bits (Table 7).
ADCRATE[2:0]/
DACRATE[2:0]
ADCMCLK/DACMCLK:
ADCLRC/DACLRC
RATIO
000
001
010
011
100
101
128fs (DAC Only)
192fs (DAC Only)
256fs
384fs
512fs
768fs
Table 7 Master Mode MCLK: ADCLRC/DACLRC Ratio Select
Table 8 shows the settings for ADCRATE and DACRATE for common sample rates and
ADCMCLK/DACMCLK frequencies.
SAMPLING
RATE
System Clock Frequency (MHz)
128fs
192fs
256fs
384fs
512fs
768fs
(DACLRC/
ADCLRC)
DACRATE
=000
DACRATE
=001
ADCRATE/
DACRATE
=010
ADCRATE/
DACRATE
=011
ADCRATE/
DACRATE
=100
ADCRATE/
DACRATE
=101
32kHz
44.1kHz
48kHz
4.096
5.6448
6.144
6.144
8.467
8.192
11.2896
12.288
24.576
12.288
16.9340
18.432
36.864
16.384
22.5792
24.576
24.576
33.8688
36.864
9.216
96kHz
12.288
24.576
18.432
36.864
Unavailable Unavailable
192kHz
Unavailable Unavailable Unavailable Unavailable
Table 8 Master Mode ADC/DACLRC Frequency Selection
PP Rev 1.0 May 2005
14
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