In any laboratory, including mine, there is a Low Frequency Function Generator.
I needed a second generator to do some tests with 4 fixed frequencies and variable output level control, nothing refined or precise.
To not buy a second laboratory generator, I do not need it in the future, I built one using EVAL-ADAU1701MINIZ.
Everything works, but I can not have a linear output level adjustment.
Surely there is a method error but which one?
I attach the project and I hope someone will explain to me where the error is.