Re: A89: Re: 4-channel sound


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Re: A89: Re: 4-channel sound




> 
> How did you do it on the 82?  Do you have source code for it?  Maybe someone could work on porting
> it to the 89.  I'm imagining GameBoy quality sound about now...
> 
> -Miles Raymond
> 

GameBoy quality sound... well, the sound quality was pretty good (for a
calculator!), but since the Z80 is sooo slow I had to use 8-bit counters
and that really reduced frequency resolution. The TI82 couldn't play the
tones with the exact frequency. This problem doesn't exist with the
TI89, since it's faster and has a lot of more registers (memory accesses
can be avoided).

When I accidentaly "killed" my TI82 (during The Big Accident (which has
nothing to do with this sound thing anyway)), I got really angry at
myself and erased all of my sources. But the theory is simple enough to
reimplement from scratch. A similar technique is used to play 6bit sound
using the PC's internal speaker.

I've tried to port it to the TI89 myself, but the sound is far too faint
when using headphones. This might be caused by different hardware or
something like that. Also, the information on direct linkport access
isn't what I call "complete"... There might be features that we don't
know yet, right?!?


References: