DDS (generating sine waves) with onboard DAC using latest PIC 16F chips?

[HankMcSpank]

EDIT: Oooh, Hank, I think you're in for some trouble in the long run..... You have your handler defined as ASM yet we're doing a host of "PBP-work" in the handler. If you're not very carefull and know exactly what you're doing that is a very likely cause for trouble and data corruption due what is described above. Either write the handler in ASM or define as it type PBP and include the Re-Enter file.

EDIT2: Currently it might not be a problem since you're not doing anything in the main loop but as soon as you start doing things there it's going to go havoc.

Good spot (cut & paste from another program + laziness!) - now changed.

The frequency is very easy to set though (presently I work out the tuning word value by way of a simple spreadsheet!)

Higher frequencies look ugly as sin (I even cranked the interrupt rate up - not much better) ...maybe it's just the simple filter I used ....hmm, not sure that PWM is gonna be the solution here (as expected the signal amplitude is related to frequency eg 400hz about 4V peak to peak but 4000hz circa 3.5V peak to peak, it'll be worse with a two pole filter) ...it looks like an R2R ladder is going to be the way forward...damnit!