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Posted By: PhillHS Adding card with loadable ROM - 11/03/21 08:58 PM
Hi all,

I have a couple of devices I want to implement one for the RM Nimbus, and another for the CoCo / Dragon, that implement a pageable ROM that isn't fixed.
So I want to have the rom loadable from a file at runtime like a floppy disk etc.

Are there any examples of such a device that are known about.

Cheers.

Phill.
Posted By: Vas Crabb Re: Adding card with loadable ROM - 11/03/21 09:04 PM
The INTELLEC 4 systems have PROM cards. But is it actually a generic PROM card that the user loaded their own PROM in, or is it just a card that has a ROM on it?
Posted By: R. Belmont Re: Adding card with loadable ROM - 11/03/21 09:05 PM
There are lots of cards for various systems with bankswitched ROMs, EEPROMs, and Flash ROMs. None of them demand-load from disk - how big are these ROMs?
Posted By: Duke Re: Adding card with loadable ROM - 11/03/21 09:25 PM
Some examples:

https://git.redump.net/mame/tree/src/devices/bus/cgenie/expansion/floppy.cpp
https://git.redump.net/mame/tree/src/devices/bus/svi3x8/expander/sv603.cpp
Posted By: tlindner Re: Adding card with loadable ROM - 11/04/21 12:38 AM
bus/coco/coco_pak includes a ROM with bank switching: coco_pak_banked_device.
Posted By: PhillHS Re: Adding card with loadable ROM - 11/04/21 02:06 PM
Originally Posted by R. Belmont
There are lots of cards for various systems with bankswitched ROMs, EEPROMs, and Flash ROMs. None of them demand-load from disk - how big are these ROMs?
In the case of the Nimbus they are I believe up to 256K, and are essentially disk images on ROM.
In the case of the Dragon they could be anywhere in the region of 16K-1024K

Doing the bank switching is not my issue here, I've done that before.

What I absolutely *DONT* want is to have to specify the ROM in the source file. The end user should be able to specify it.
I'll take a look at the examples people have given. It also strikes me that the QL ROM cartridges may also be worth looking at.

Cheers.

Phill.
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