Maybe this belongs in the retro-computing section, but I've put it here since a similar topic was placed here not long ago:-
https://www.eevblog.com/forum/projects/6809-single-board-computer-project/And I think those that read that, would probably want to see this.
In the above thread, I showed this Compacta Uniboard, a 6809 SBC.
I thought I'd lost the documentation, but I've found the schematic for those interested.
Picture and schematic are on Imgur, as they are too large for here, while keeping full resolution, 4MB-5MB.
(They're the sizes I uploaded, but they "save image as" to smaller sizes?!)