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Hello,

It's been some time since I went here.

I will tell you a bit of history first, then I will ask a few things if you don't mind.

Back in late 70s, the Rockwell corporation made the AIM-65 SBC. And they wanted to enter Spain but had no distribution lines there for their computers, so they relied in a company called COMELTA (Compañía Electrónica de Técnicas Aplicadas). And they distributed the computer. That being said, COMELTA cloned the computer and modularized for industrial use, the product was called "Sistema CR", and as an instance of that ecosystem the fully AIM-65 compatible "Drac-1" was released.

While the Drac-1 had the CR-101 of which I have practically no data, I was able to study a bit the CR-124 and two of their derivatives: the PYCMESA EP-324 and the J.B. Electrónica Industrial JB-176. For some reasons I am making also my own derivative too.

I would like to first emulate my derivative and then emulate the three other related boards. The reason is that I modified the design to add self-diagnostics capabilities to the board, and I have a version of the diagnostics ready but no hardware to test it. At the same time, I can obtain the original cards, but without firmware.

I cannot remember many things that are required of a basic driver to work. For starters, I have a 64KB ROM at 8000h-FFFFh, which contains two pages of 32KB. Page 0 contains the diagnostics, page 1 is left at discretion of the user (in practice is as if they were two different memories of 32KB). The page is switched by means of a jumper. What would be the best way to implement this?

At the card there's also RAM memory from 0000h-03FFh and two VIAs at 04xx and 08xx respectively. Being a backplane-based computer, functionality of a single card is very minimal.

It is a bit embarrassing, but I forgot how to write a skeleton driver...

Thank you in advance

For the jumper, I'd do it as a DIP switch.

There's a working AIM-65 driver (aim65.cpp) and a bare skeleton for the later AIM-65/40 (aim65_40.cpp). The Drac-1 should presumably be a clone system in the main aim65.cpp.

Probably yes, but maybe it is not the best option. The Drac-1 is not a SBC, but an instance of application of Sistema CR of backplane-based computers. It is compatible with the AIM at the same time it is expandable with the CR modules... and other computers built with the very same modules may not be AIM compatible.

At this moment I have updated my source code at github. For some reason, still doesn't like the VIAs.

Thank you in advance!