Sinewaves using interrupts.

[ScaleRobotics]

Thanks Hank! Glad to hear I am not the only nerd in the room.

By jove, I think you've got it. Since the frequency is made from the value of the 16 bit timer, your precision is pretty good. Of course pre-scalers and post scalers could be used, depending on which timer, to broaden your frequency even more. So I would say you have lots of flexibility on the frequency.

I am a filter newbie, so I only know that they are tuned to frequency. I noticed that Bruce had a book on filters ... and almost asked for that one as well....

The 36 steps I used make it possible to offset the sines by 10 degree steps. Some people use 72 steps in their tables, and then that would be 5 degree offset. Not quite sure what you plan.

What I'm possibly thinking of doing, is to extract the frequency from an incoming guitar signal, then 'PIC generate' other sine wave frequencies from it (eg double the incoming guitar frequency) - but for maximum sonic flexibility, I have an intended use that rather than change the incoming frequency, (ie generate the same PIC generated sine frequency as the incoming guitar note), only shift the phase vs the original incoming signal.......do-able, or is this getting too taxing for a PIC?

I'm not sure if I follow exactly. You sometimes want to double the freqency, and sometimes off set the frequency, but keep the frequency? In any case, I think there is plenty of horsepower in the PIC to time your incoming frequency and also do sine out using hpwm. That is, as long as you find a good filter/sustainer to get a single frequency in for it to measure.

http://www.picbasic.co.uk/forum/cont...-DT-interrupts