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.
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.