Direct digital synthesis using Atmel AVR

[egasimus]

Is it possible to have an 8-bit Atmel uC output 4 frequencies, two in the audio range (15-5000Hz), and two sub-sonic (0.1-10Hz)? This has been bothering me for a couple of days - do you think an ATtiny clocked at 20MHz has enough power to replace two VCOs and two LFOs in a synthesizer? I made some calculations, which led me nowhere, but the idea isn't ready to leave my mind and head for oblivion just yet. I've seen this done with one VCO (link, link - second example goes into hundreds of kHz!), but both cases use 4 pins of the MCU as a DAC, and I'd prefer using PWM.

So what do you think of my idea? Is it feasible?

[wavley]

Yep, there sure is and it sounds AWESOME!

http://meeblip.noisepages.com/

http://www.diystompboxes.com/smfforum/index.php?topic=89917.0

[egasimus]

Awesome stuff! And only at 16MHz Many thanks!

[nexekho]

It's quite surprising what you can get done in 16mHz when you aren't dribbling cycles away into drivers and APIs.

[egasimus]

You're right. I was amazed that it's 16MHz as opposed to 20 or 24. My calculations led me to think even 32MHz could be too slow, but I just saw they were incorrect. Bah. I'm an ass.