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Clearly the 6502 is executing the ROM correctly (and also must be reading/writing RAM correctly), and the ULA is reading the char ram correctly, but is reading the screen ram with bit 0 stuck at 0.

So it looks very much like a busted ULA.

Never saw that :) Interestingly, the characters are duplicated but not the pixels inside the characters, so that's probably not a bus access issue. It is reading all the even RAM addresses, so it does appear to be an address bit 0 issue. It could be between the ULA and RAM, but not between ULA and ...

I think you mean ULA :) To change the ALU he'd have to cut open the 6502 and remove and replace a section of the die! It looks like the bit 0 address line to the ULA is stuck. Edit: Which means the problem could be on the PCB trace to the ULA, or inside the ULA. An oscilloscope on that pin of the UL...

I still think a good idea for a future revision of the cumulus would be to map in a rom image from SD when software de-asserts romdis.

Open the menu, select "Load snapshot", select the snapshot file... and thats it.

Note that oricutron snapshots are not compatible with euphoric snapshots.

if you look at the oriic google code page, I created ready made atmos and oric 1 keyboard images for the wii port of oricutron.

as I recall, its not as simple as enabling sdl keyboard translation, otherwise I would have done it. the problem is modifier keys like shift or ctrl. If you let sdl map keys for you, you won't know what keys were pressed to give you the ascii code. What if the user is playing a game where shift and ...

Yep.. its horrendous. This is why I haven't tackled it in all this time.

Cool. All help welcome

ok cool. Send me the email you use (or want to use) as your google code account via PM when you're ready.

Good work! I look forward to your changes going into the emulator once they are ready.

Speaking of which, would you be interested in having commit access, and taking over maintenance of the Mac port? The Mac port is a bit unloved at the moment, and needs some TLC

an idea for cumulus 1.5 maybe...

Could the cumulus sidestep any ROM issues, by mapping in its own ROM image read from the SD card when software tries to enable the ROM?

ahh sorry! Thanks for your help, though. Contributions to oricutron are always welcome.

Fixed in SVN. If you need a WIP build, let me know.