Yeah, the 6503 does seem rather limited that way, with very few advantages, the main being board space, I assume.
Probably why you don't hear much about it. I suspect the memory capabilities are adequate for a small "trainer" like system.

I'll admit the main choice over the 6502 was that I have ...

Fantastic- thanks!

--Christoffer

Okay, this I hadn't anticipated: Most of the 6502 interrupt/reset vectors is outside the address space.
Would it just be the lowest 12 bits of the same addresses?

--Christoffer

Oh, sorry. Missed the point that it was literally the same die in there. I guess that'd make it sorta software compatible, yeah.

--Christoffer

It's an old NMOS 6502 but with only 4K of addressable memory space, and no SYNC or RDY or phase 1 or SO\ pins. You can see the pinout on page 10 of the 12-page .pdf data sheet on this site, at http://6502.org/documents/datasheets/mos/mos_6500_mpu_nov_1985.pdf .

The RIOT ICs are very rare, so ...

This is pretty much exactly what I've been looking for!
- Is it possible to program the atmega328 by programming the .hex file (/debug folder) to it with a universal device programmer (Eproms, mpu's, etc)? - Or would you have to compile a proper .hex dump with Atmel studio?

--Christoffer

Hey! First post here! - I'm an ex-EE student from Denmark, and have been into building vintage computer systems for some years now, though non-6502 based. Messed around with the 8085 and 6809 for a while, even have ½ a cosmac ELF somewhere, that I never finished. Latest I've been working on a small ...