🚀 go-pugleaf

  Sir Richardson spoke forth saying:
"Re: Color Computer 3 inte" toward 
 on 12-14-92  17:12
 MR> On a similar vein, about 3 months ago I tried to get a digitized
 MR> sound driver working under level II, using the FIRQ.  The idea was to
 MR> use the empty space in $FExx and vector the FIRQ there, bypassing the
 MR> OS9 stuff (which was sloooow, and would crash if used!).  I got to the
 MR> point where I had a simple square wave generator running in ~$10
 MR> bytes, and which worked.... for a bit.  It would always crash after a
 MR> while, tho, as it seemed the IRQ was interfereing somehow.  So I
 MR> finally dropped it.  Too bad, a background sound driver would have
 MR> come in real handy.

    Where does MicroWare hide the kernal?  If I remember there is
    a task switch map.  (T0/T1).  this allows the computer to
    rapidly switch to the kernal and then return to the program.
    The question is how do they implement it?

SYSTEM MEMORY MAP:
 RAM      00000 - 7FFFF (512K bytes)
 ROM      78000 - 7FEFF when enabled
 I/O      XFF00 - XFFFF I/O space and GIME regs
 
64K PROCESS MAP:
 RAM       0000 -  FEFF (possible vector page FEXX)
 I/O       FF00 -  FFFF (appears in all pages)

    now acording to this FExx is NOT empty.

Note: the Vector Page RAM at 7FE00 - 7FEFF (when enabled), will appear instead
 of the RAM or ROM at XFE00 - XFEFF. (see FF90 Bit 3)

And this states the Vector page RAM is there when enabled.
That may have more to do with your problem.  I was considering
constructing a MOD player for the COCO (that would be cool).
of course the big limitation is memory (as ussual).  Another is
adjusting the interupt rate (60hz on the CC][ the CC]I[ has a
variable one).

To solve the memory problem I figure I can chop the lower 4
bits on each sample byte.  Then one can have 2x the sample space.
This wouldn't make a difference since the D/A has only 6 bits of
resolution anyway! (add 4 4 bit samples the result is 1 6 bit
value).  It may not sound great but it might be a first for the
Coco (who cares?).  It might be able to only work on the CC3
because it may be the only coco FAST enough to do the digital
mixing.

				Stephen Cyberman@Toz.Buffalo.NY.US
			 Mangled on Tue  12-15-1992  at 17:51:19

... Click ... click ... click ... damn, out of taglines!
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