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ADSP 21489 SRC to 8 and 16kHz

Question asked by Eagle on Dec 14, 2011
Latest reply on May 9, 2016 by jiangang

Hi,

I am using a ADSP-21489 EZ-Board and took the C Block-Based Talkthru  48 kHz example, which I changed in the I2S mode. Now I try to integrate two sample rate conversions.
What I'd like to do:

 

- take 48 kHz samples from the 4 RCA jacks, decimate the sampling frequency to 8 kHz
- my existing software takes the 8 kHz samples, outputs samples with 16 kHz
- upsample those to 48 kHz, output to the 8 RCA jacks

 

I use the SRC1 unit between the ADC and SPORT1 (Rx) and SRC0  between SPORT0 (Tx) and DAC.

 

Question:

 

SPORT control registers:


    //12.288 MHz SCLK from AD1939
    *pDIV1 = 0x???;
    *pDIV0 = 0x???;

 

Where can I find out which value I have to take for the div? Is there a look-up table or an easy way to calculate the values for the upsample and downsample? I can´t find any references in the manual.

 

Thanks, Eagle

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