[Coco] Another ROMable NitrOS9 question

[Wayne Campbell]

I downloaded this pdf awhile back. Unfortunately, it is incomplete.

Wayne
 On Jan 13, 2014 5:34 PM, "Tormod Volden" <lists.tormod at gmail.com> wrote:

> On Mon, Jan 13, 2014 at 11:03 PM, Arthur Flexser wrote:
> > I think the problem is not so much disabling the ROM as it is in
> > booting your cartridge.  Even when a cartridge is used, the ROM is
> > still required;  there's a routine in the ROM that checks for the
> > presence of a cartridge and jumps to the cartridge address space if
> > one is found.  It may be possible to do what you want without
>
> I guess billg999's idea was that the cartridge does full address
> decoding and acts on the BASIC ROM address space, and not on the
> normal cartridge address space. Maybe it is enough to use the SLENB
> input to keep the internal ROM from activating?
>
> BTW, I just found this:
> http://www.frontiernet.net/~mmarlette/Cloud-9/Support/CoCo%20OS-9%20ROM.pdf
> - Very nice documentation!
>
> Tormod
>
> > completely desoldering the ROM, though, if you clipped an appropriate
> > pin and routed the line to a piggybacked EPROM.  Maybe with a switch
> > so that the CoCo 3 could still be used in normal mode when desired.
> > That would give you a lot of space for code, for you'd have not only
> > your cartridge space but also all the space in your EPROM freed up by
> > its not having to contain BASIC.  (There's a full 32K EPROM inside the
> > CoCo 3, if I remember correctly.)
>
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