Hi Mark, I don't have a tutorial, but may be able to assist with sample code. (and other help if required) I am working on one of these at the moment. Have just about got it working OK - am aiming at using it in an entry in the Circuit Cellar Contest. Basic details are:- Using Atmega323. (or AtMega32) 64 sample x 10bit (results in 32 output frequency bins. e.g 8KHz sampling will result in a resolution of ~125Hz) Conversion time ~20mS on a 3.6864 MHz clock (Slightly dependent on signal complexity as I only calculate the magnetude square root if the frequency component is significant) - I am aiming for speed rather than size RAM Memory requirement (hopefully) < 300 bytes. (Using same array for input, calculation & output - am still working on this & have yet to decide which arrangement suits me best) Flash Memory requirement is about 3k or so for the FFT module. I am using the BASCOM environment for debugging & simulation & have found some problems with their multiply directives, although that now appears fixed.If I can use the mulsu & muls directives I may be able to shave a few 100uS more off the conversion time. I am also thinking of writing an 8 bit version, possibly for up to 128 samples in length. As this will use the 8 bit multiply directive for most multiplies, then program operation should be similar in speed to the 10 bit 64 sample version . I can send you more info if required, but note that this is still "in process" so there are probably bugs etc. hanging around. I have also offered a copy to Mark for inclusion in a BASCOM library so it may turn up there in a little while. Right now I'm trying to tie the bits together so I can get a FFT or spectrograph type display on an LCD, so I can monitor what is going on in realtime & see if the thing is actually working as advertised. Richard P Mark Jordan cc: Sent by: pic Subject: [AVR:] Looking for an AVR FFT tutorial microcontrolle r discussion list 19/04/04 02:30 Please respond to pic microcontrolle r discussion list Hi, I'm looking for a tutorial on how to write a FFT routine in assembler language for the AVR AtMega uP. Have found one dealing with the Goertzel algorithm and it works very nice. Google shows me zillions of FFT links, but nothing using an AVR. Thanks for any help. Mark Jordan -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body