29 Oct
2010
29 Oct
'10
1:55 p.m.
> Just because a CPU architecture has IO
instructions doesn't mean you
> can't do memory-mapped I/O.
I beleive Steve Ciarcia said in one of the Circuit Cellar articles in
Byte many year ago that any processor that could access memory could have
memory-mapped I/O.
I would add that in the case of a system (rather than a bare processor),
it helps if there's some spare space in the memroy map :-).
And there were other PC displays, that didn't use memory-mapped video
if by 'PC' here you mean something descended from the IBM5150 then I am
curious. All the IBM dipslay adapdaters that I can think of were memory
mapped. Yes, even the PGC had a memory-mapped CGA emulation.
I do rememebr reading about TMS34010 development boards for the PC. Is
that the sort of thing you were thinking of?
-tony