Antonio Almeida wrote:
>
>    Has anyone tried to implement FFT with PIC?
>    I'm tryng to do some guitar effects and i don't want
>    to use a DSP (to expensive). At first glance, the
>    worst problem is the memory. Any ideas ?


The problem is border line computing power. It is right
on the edge. The 17c42a and 17c44 have hardware multiplies
and that helps. We added a switch in MPC (It may be
undocumented) to generate multiplies in line. That was
enough implement some basic FFT filters. As you have stated
RAM in some of the other parts may be a problem.

Depending on the effect the amount of computing power
may be less of a problem. Some filters can be implented
with very little code.

In general exchanging code size for speed will be a big win
in this type of application.

Walter Banks