Deckard wrote:
The big problem with my design is that you can't swap the simulated floppy on-the-fly.I don't like to switch off/switch on my computer each time I want to boot a new image. Why don't you add an entry point in the rom code with something like that:
Let's think together about it. The ROM is huge, but only 256 bytes aremapped in at a time. When the unit operates in floppy emulation nibble mode, the visible ROM page is a copy of the real floppy controller's ROM. It doesn't have much space for extra code, but suppose we can somehow map in another ROM page - say with a physical switch. How do we make the 6502 jump to this code? If a program needs to be run for that, why does it need a ROM entry point and not talk to the AVR directly?
I guess one option could be a modified PD8 that would override the $F8 ROM (like a ROM card does) and point a reset vector to its own code.
-Alex.