[Coco] Nitros9 L3

[Robert Gault]

Bill Nobel wrote:
> Yes, I saw those defs, but I notice in my disarm of Nitros9 module that it
 > uses System DP starting at $0000 which was def’d in level 2 as FHL/Isted
 > WD1002-05 base address.  It is used now as pointers to I'm assuming
 > SCF/RBF base addresses.
>
><snip>
> Bill Nobel
>

Bill,

All the source code I've seen for Level3 assumes a 6309. The 6309 requires a 
trap for illegal coding and uses the address at $FFF0 to jump to the code. Tandy 
never used that (6809 only) so the ROM at $FFF0 reads $0000.
Given the above, a 6309 requires some code at $0000 to at least jump to the 
actual trap routine.

You could try leaving out any trap code but that would be risky. Sooner or later 
something will go wrong and vector to $0000 assuming there is valid code at that 
location.

Robert