I can remove RPULL if I control an ADAU1701 input pin through an external IC
It depends on the output topology of the IC that is driving the GPIO input. Most parts will drive low and drive high so you most likely will be able to omit the pull-up resistor. If it is an open collector/drain output stage then you will have to use a pull-up.
Now for the lower SigmaStudio drawing you show MP3- driving MP11. Is this an interim step in your design and you are planning on doing more with the MP3 signal in SigmaStudio or are you only going to pass the signal through the DSP?
If you are only passing it through the DSP can you please share why you are doing this?
external IC sends 2 logic states 0 and 1 as if it were a button.
The problem is not the cost of resistances but the limited hardware space, so I want to eliminate everything that is possible.
However this is the least problem the biggest one is that for which we are discussing this post:
Retrieving data ...