Integrating Altera's FFT IP Core into Nios System

First i don't know the Viterbi IP Core. In my case where i had to connect the FFT to the NIOS CPU the main problem was to make a conversion from Avalon ST to MM interface as the FFT uses the ST interface both on input and output and the NIOS CPU uses the MM interface so you cannot directly connect them.

Anyway the best way to connect the FFT is through the use of Scatter-Gather DMA's. Not only do they the interface conversion for you, they even free up the CPU because the task of delivering the input data to the FFT and the results from the FFT is done by those DMA's (you need 2, one for the connection from NIOS CPU to FFT and another one for the other way).

Hope this helps and good luck

Flo