1 Jan
2009
1 Jan
'09
10:12 a.m.
Philip Pemberton wrote:
Kind-of. I figure that a combination of you, Sprow and JGH are probably the
best three to get something like this up and running... :-)
Sadly all my TUBE docs are in storage*, and I'm not sure what I have scanned
here with me - I know I've got some TUBE notes from Hugo and a TUBE app note
(but I think the latter's online anyway).
* i.e. stuff like the A500 manuals might have something useful inside.
Jules Richardson wrote:
Yeah, I sold a couple on there just over a year ago - pretty much my only
foray into selling on ebay (and not something I care to repeat). I offloaded
another four or so via word of mouth. I've got another six Acorn ones with the
TUBE ULA but as they're all different I don't want to part with them I'm
afraid!
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
:-/
Yeah. I blew one up by plugging a copro in backwards once and felt guilty (in
my defence, the silk-screening was wrong on the copro PCB, but I still should
have checked with a meter first!)
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? :) 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.
To be honest, lay out your own 6502 board. I've got schematics and ROM images,
and there's nowt special to it, assuming you have the ULA.
I keep forgetting to poke Sprow about buying a ULA - I still need one for one
of my Springboards, and I suspect that the one in my '286 copro might be duff.
cheers
Jules