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6.7 Filters Tab
Kit Operation
To use the PC software to find the ideal values of P, K, and R for a given PLL input frequency and desired
Fsref, the Fsref must be set using the switch on this tab; it can be set to either 44.1kHz or 48kHz. Once
the Fsref and PLLCLK_IN values are correctly set, pushing the Search for Ideal Settings button starts
the software searching for ideal combinations of P, K, and R which achieve the desired Fsref. The
possible settings for these parameters are displayed in the spreadsheet-like table labeled Possible
Settings. Clicking on a row in this table sets the P, K, and R values in the software and updates the
PLL_OUT and PLLDIV_OUT readings, as well as the Actual Fsref and Error displays. This process does
not actually load the values into the TLV320DAC32, however; it only updates the displays in the software.
This allows for different possible solutions to be selected and the error evaluated before loading into the
device.
When a suitable combination of P,K, and R have been chosen, pressing the Load Settings into Device?
button will download these values into the appropriate registers on the TLV320DAC32.
Re-sync of the audio bus is enabled using the controls in the lower right corner of this screen. Re-sync is
done if the group delay changes by more than ± FS/4 for the ADC or DAC sample rates (see the
TLV320DAC32 data sheet). The channels can be soft muted when doing the re-sync if the Soft Mute
button is enabled.
The TLV320DAC32 has a very rich feature set for applying digital filtering to audio signals. This tab (
Figure 4 ) controls all of the filter features of the TLV320DAC32. In order to use this tab and have plotting
of filter responses correct, the DAC sample rate must be set correctly. Therefore, the clocks must be set
up correctly in the software following the discussion in Section 6.6 .
Figure 4. Filters Tab
SLAU201 – November 2006 TLV320DAC32EVM and TLV320DAC32EVM-PDK 13
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