Audio Input through Auxiliary ADC on ADAU1701
Hi,
ADAU1701 has four 8-bit Auxiliary ADCs. I need to feed audio input (8-bit resolution is OK) through one of the four Auxiliary ADCs and route it to a 24-bit DAC.
How is the data format handled in this case? Is 8-bit data from Aux ADC filled up in lower 8 bits of 24-bit DAC, with upper 16 bits set to zeros?
Is there a SigmaStudio block that can handle the above data type conversion?
Can I use a gain block to multiply the 8-bit Aux ADC data so that it fits in the upper 8 bits of 24-bit DAC?
Thanks,
Shyam.
Audio Signal Processors
adc
aux
SigmaDSP Audio Processors
adau1701
Hello,
If you input audio into the aux ADC, you will still get a 5.23 format number in the DSP core. Basically, the ADC converts the number to 1.23, with the 8 bits of audio in the MSBs and the LSBs filled with zeros. We then add on 4 bits of headroom to match the DSP core's 5.23 word length. On the output side, we simply truncate the headroom bits to get back to 1.23.
I made a diagram to explain. The red As are Audio data. The yellow Hs are headroom. The blue 0s are zero padding.
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