31 Dec
2008
31 Dec
'08
5:20 p.m.
Jules Richardson wrote:
Not *completely*, AFAIK - although there are fragments
all over the
place. I think there's enough amassed wisdom around now that it *could*
be done though, because the software to drive either side is understood
enough, as is the electrical (physical) interface, and there are still
survivors of all the vintage hardware which made use of the ULA.
What's available appears to be fairly thin on the ground though. A quick
search on 'the bay' revealed tons of Master 128s and BBC Bs, but nary a second
processor in sight.
I'd feel a bit bad if I ended up killing a ULA or a 2nd processor though :-/
The problem is that very few people have both a grasp
on that knowledge
and the ability to do the necessary electronic design - it's only really
worth it for a drop-in replacement (i.e. a single chip or a very small
daughter-board to plug into the ULA's 40-pin to DIP socket) because (as
Phil says) it'd be a reasonably large board to do it as discrete logic.
Oh, is that a challenge I hear? :)
Once I've sorted the floppy disc R/W project out (probably around Easter), I'd
be more than happy to have a crack at cloning the Tube ULA. Seems Sprow has a
few ULAs left, and one of those (assuming it's working) should be enough to
clone the thing, but a 6502 2proc (either cheesewedge or internal, as long as
it works on a Master 128) might be handy for a bit of live testing, if such a
thing proves necessary.
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/