[Coco] Orchestra 90CC

[Joel Ewy]

Jeff Teunissen wrote:
> ...
> A 256 byte ring buffer being drained by 8KHz mono has to be updated at least
> every 32ms. For 22050Hz stereo it's a much tighter 5.8ms...but that should be
> well within the capability of, say, a 28.63636MHz (heh) C5 even while
> multitasking in NitrOS-9.
>
> Obviously, this all assumes that the sound hardware (like the VDG in a
> CoCo1/2) is accessing RAM when the '09 isn't, and also that there's a reliable
> and accessible clock source (no halting floppy interface allowed, or you'd get
> the same endlessly-repeating samples that you get when a Windows box hangs
> while there is sound playing).
>   

And if this were implemented in an FPGA (correct me if I'm wrong, those
who know better than I) adding 256 bytes of special-purpose RAM in the
FPGA itself, separate from the normally-addressed system RAM, wouldn't
take too much doing.  In that case, the CPU fills the buffer and the
sound hardware goes off on its merry way without respect to what the
rest of the CoCo is doing.

JCE