[Coco] 32K carts?

[Roger Taylor]

At 09:52 AM 10/22/2007, you wrote:
>Hi guys,
>
>Is there anything special about a 32K cart?
>
>I'm trying to work out why I can't get Arkanoid or Rampage to run out of
>EPROM on my cart board. I assumed the top 16KB would get mapped into $C000
>and the ROM bootstrap code then enables the full 32KB of external ROM space.
>But it would appear to me that Arkanoid at least doesn't do this.
>
>What I think is happening atm is that when I enable the 32KB jumper on my
>cart, the internal and external ROMs both drive when the CPU is accessing
>memory from $8000-$BFFF and it's not a pretty sight... :(
>
>So I'm wondering how 32KB carts actually function?!?
>
>Regards,



That's something I never learned, but it seems that the internal CoCo 
3 ROM area from 32768 to 49151 is there no matter what, and a 32k pak 
might have to switch in 16K at a time starting at 49152/$C000, no?

Hopefully you can add a jumper or two on your boards to fix any 
problems like this.