ATTiny + FFT

Other Hardware 3rd Party Boards
1

Hi, I'm fooling around with FFT and came across this library by Neurolec http://neuroelec.com/2011/03/fft-library-for-arduino/

The library works great on my Arduino Uno (ATMega328), however I'm interested in getting this to work on the ATTiny85.

Out of the box this won't work, because the ATTiny85 has a reduced instruction set, in particular the Neurolec library makes use of various arithmetic functions, including:

  • FMULS, FMUL, FMULSU, MUL, MULS and MULSU

Is there an alternative library or instruction set that can do some of this work, or has anyone had any success writing a small FFT library for use on the ATTiny?

2

All good, I found this post by deif, who provided a modified 8 bit FFT, which is very suitable for an ATTiny. I'm using an ATTiny85

You can read the post here http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1286718155

For those who venture down this path, keep in mind the following points:

  1. the returned results stored in data is of datatype Char. You'll need to convert it to a decimal to make it useful, for example: String.print(data*, DEC)*
    2. The fix_FFT library was written a few years ago, so the reference #include <WProgram.h> will work fine when working in Arduino 022, but for Arduino 1, you'll need to update the include to #include <arduino.h>
    Enjoy
3

Thank you for the follow-up.