How to realize a music pitch effect ?

I assume you mean pitch shifting, correct? Most pitch-shifting algorithms require frequency-domain processing in order to be done transparently. Unfortunately, SigmaDSP's hardware architecture does not (yet) allow for frequency-domain processing, so this is not possible on the ADAU144x.

Although there are some methods of doing pitch shifting using stream-oriented processing, the results don't sound great and they are very processor-intensive.