Use both internal and external TDM DACs

Hello NOLA,

Yes, you can use the internal ADCs and DACs at the same time as the serial port.

I just looked into my folder of example projects and found this one that is setup for TDM4.

This will give you the basic idea of how to do it.

There are a few little important details. Both the ADAU1701 and the AD1938 require the master clock be EXACTLY 256xfs (unless setup for a different rate but 256x is standard). If the sampling rate clock or the bit clock is wrong it will mute the DACs.

In my project I had the 1701 be the clock master. You can do it that way if you like but you will have to supply the same master clock to both parts.

You can end up with 2 ADC inputs and 8 digital inputs and then 4 DAC outputs and 8 digital outputs.

There are a lot of notes in the project explaining things.

Dave T

ADAU1701 Analog In or Internal OSC to TDM4 output then TDM4 input to DAC outputs.dspproj

Hi Dave and NOLA,

The six -1701s in the mixer made where I work all have busy analog IOs while passing audio among themselves in a circular TDM-8 path we've nicknamed 'the Capitol Beltway." So, this is quite possible.

Best regards,

Bob