[sdiy] Polyevolver internals

[Eric Brombaugh]

On 12/29/2009 04:21 PM, Tom Wiltshire wrote:
>
> Thanks Eric. That pretty much clears that up. I guess Karl is right
> about the long delay lines needing more than a dsPIC, and a ADSP2191
> would give you a lot more scope.

Depends on how long a delay you need - If you're willing to strap on an 
external SRAM you can get quite long delays from a dsPIC, even at decent 
sample rates. If you're trying to get by only with internal RAM though 
it is pretty limited. Really only good for phaser/chorus ranges.

> <returns to bench>
> That lets me off trying to squeeze digital oscillators into this chip
> too, then! Phew!

Well, digital oscillators are another kettle of fish entirely. I've had 
pretty good luck building a variety of oscillators in a dsPIC. Depends 
on what you're trying to do though.

No idea how well it would work to have both DCOs and digital oscillators 
running simultaneously though. Could end up with some IRQ contention if 
the DCO hardware needs much babysitting.

Eric