Add to NMS8250 third SLOT

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Por luppie

Paladin (854)

Imagen del luppie

10-05-2017, 10:00

floppiefrans wrote:

Someone ever managed to get this working?
Luppie, did you manage to get it work?

Nope, unfortunately not. I still do have this machine waiting to finish it, but I still haven't found a solution.

Por Wild_Penguin

Hero (586)

Imagen del Wild_Penguin

10-05-2017, 19:39

I wonder what the problem is? I mean, there are loads of modifications that insert a ROM into this "free" slot in the NMS825X, and those work fine (I've used DOS ROM in this slot). What is left from these ROM-only expansions to make a full slot? I/O? But that shouldn't be too difficult, since I/O is not slot specific (but can be "chained" instead? Or am I missing something? R/W signals?

Por floppiefrans

Master (237)

Imagen del floppiefrans

16-05-2017, 14:36

Why use a 74LS15 and not a 74LS11?
Is this the problem?

Por Eugeny_Brychkov

Paragon (1119)

Imagen del Eugeny_Brychkov

16-05-2017, 16:48

floppiefrans wrote:

Why use a 74LS15 and not a 74LS11?

LS15 has open collector outputs, thus they can be connected together to form common BUSDIR signal (if I understood instruction properly).

Por floppiefrans

Master (237)

Imagen del floppiefrans

16-05-2017, 23:26

OK, I understand, but instructions to build third slot are not correct.
I does not work at all. computer dos not start up...

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