Software - Hardware connection

Ref developing RISC OS on new/different machines.
Is there anyinfo around on the connection between Software & Hardware – perhaps
more in a Schematic/pictorial way? (Draw/PDF)

That explains what is needed to be done to get RISC OS running on a new ARM
machine.

Hope that makes sense :-|

"There’s a very rough porting guide on the wiki, along with various other bits of technical documentation."

perhaps more in a Schematic/pictorial way?

If a hand sketch is prepared, it could then be reworked using Draw.

What kind of diagram are you interested in? Something like the ones on this page or this which show how the different parts of RISC OS fit together?