[Coco] joystick plus real-time sound?

[Robert Gault]

Roger Taylor wrote:

> Folks,
> 
> If I'm not mistaken, there is no way on a CoCo to poll the joystick 
> while doing real-time audio without introducing interference.  The same 
> DAC is used to output the 6-bit sound and set the voltage for the 
> joystick axis comparitors.
> 
> When you set up the PIA to sample the joystick axis, I think a pop or 
> click sound is introduced if the mode was in 6-bit sound mode.  Doing 
> this frequently back and forth scares me with the thought.  :)  
> Ofcourse, on an emulator it probably doesn't do this.
> 
> I could be wrong, but I think this is why I made my Spider-Hype games 
> use only the keyboard.  I guess having real time music and sound effects 
> has a cost.
> 
> 

I think you can time share with careful coding. I remember doing that in 
some software. I'll see if I can find the program source code.