[Coco] Another ROMable NitrOS9 question

[Tormod Volden]

On Mon, Jan 13, 2014 at 11:37 PM, Arthur Flexser wrote:
> On Mon, Jan 13, 2014 at 5:33 PM, Tormod Volden wrote:
>> 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?
>
> Well, certainly any cartridge can take over the $8000-BFFF RAM space
> once it has booted up.  No need to disable the Basic ROM in order to
> accomplish that.

If you mean by "cartridge booting up" to be started by the BASIC ROM
detecting it and jumping to cartridge space, that was not what I
meant. I meant booting directly from the reset vector into the
cartridge acting instead of a BASIC ROM. But I admit it is not very
useful unless you want for instance to make a larger ROM than 16K.

Anyway, it depends on what billg999 wants. If he's OK with a
cartridge, no need to disable the BASIC ROM by hardware, and rather do
like you suggest here, going through a normal cartridge ROM, which can
copy itself into all-RAM. If he wants the cartridge port free,
piggy-backing internally is probably best.

Tormod