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First post, by Jo22

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http://www.baltissen.org/newhtm/c64isa2.htm

..

Fascinating! 👍

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Reply 1 of 13, by digger

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Amazing. The DEC Alpha XPpci33 "NoName" OEM motherboards already proved that the ISA expansion slot wasn't exclusive to the x86 architecture. But getting it to work with a much older 8-bit architecture such as the C64 is mind-blowing.

It makes for some interesting possibilities.

Reply 2 of 13, by Caluser2000

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When was that page updated?

There's certainly some cool stuff coming out.

ISA slot are just that-slots. They can be use for whatever purpose on decides to do with them.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 3 of 13, by AlaricD

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Caluser2000 wrote on 2021-08-08, 18:00:

ISA slot are just that-slots. They can be use for whatever purpose on decides to do with them.

I'm rather impressed they were able to use an IBM Monochrome Display Adapter with the C-64. That's a pretty neat trick getting it to work, even if the MDA is text only.

Reply 4 of 13, by digger

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AlaricD wrote on 2021-08-08, 21:14:
Caluser2000 wrote on 2021-08-08, 18:00:

ISA slot are just that-slots. They can be use for whatever purpose on decides to do with them.

I'm rather impressed they were able to use an IBM Monochrome Display Adapter with the C-64. That's a pretty neat trick getting it to work, even if the MDA is text only.

Of all the ways of getting a C64 to display 80 column text, I'm sure this is the most high-quality option yet! 😁

Reply 6 of 13, by Benedikt

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AlaricD wrote on 2021-08-08, 21:14:
Caluser2000 wrote on 2021-08-08, 18:00:

ISA slot are just that-slots. They can be use for whatever purpose on decides to do with them.

I'm rather impressed they were able to use an IBM Monochrome Display Adapter with the C-64. That's a pretty neat trick getting it to work, even if the MDA is text only.

Unfortunately, you are going to hit a brick wall as soon as something comes with an option ROM for hardware initialization.
Most pre-EGA graphics cards and early sound cards should work, though.

Reply 7 of 13, by digger

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Benedikt wrote on 2021-08-10, 20:12:

Unfortunately, you are going to hit a brick wall as soon as something comes with an option ROM for hardware initialization.
Most pre-EGA graphics cards and early sound cards should work, though.

I'm not sure that's true. Weren't all early PC graphics standards, up to and including regular VGA, compatible with IBM's (and Hercules') respective cards at the hardware register level?

The Bochs project has a generic VGA BIOS that you can flash to any graphics card, as long as it's fully IBM VGA compatible, albeit at the cost of any high res or high color VESA stuff. Theoretically, such generic BIOS code could be ported to 6502 assembly code. At the very least enough of it to get some rudimentary functionality working, such as text mode.

Reply 8 of 13, by Benedikt

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That's the brick wall I was referring to. Of course you can bulldoze it, to keep the metaphor, but porting the card's option ROM to a different instruction set architecture is far away from a plug-and-play experience.

Reply 9 of 13, by mr.cat

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In the 90s there were Un*x servers and workstations that had EISA, so they could have used regular ISA cards. They would have had this problem too.
I think they just made their own card variations with a customized rom?
Anyone used something like that?

Reply 12 of 13, by Benedikt

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digger wrote on 2021-08-12, 12:37:

It's just bootstrapping/initialization code, so maybe it won't matter if the emulation is slow?

It depends. Many cards, like EGA, VGA or HDD controller cards, will want to patch interrupt handlers. The code might also want to use e.g. a non-existent DMA controller.

Reply 13 of 13, by BitWrangler

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Fascinating... though not because I want one in a C64... more thinking about interfacing to 8 bit project boards etc... everybody wants a CP/M box that takes ISA card right? 🤣 .. yeah I bet y'all are thinking "noooo donotwant, cards rare enough already!"

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