BBC Second Processor Tube ULA (was Re: What kind of IC is this)

[Tony Duell]

Happy new year! You know, I find it a little hard to accept machines made 
in 1999 as being 'classic' :-)

> > * A drop-in replacement for Acorn's TUBE ULA would be nice - I used my=20
> > last remaining spare a couple of years ago, and still have a couple of=20
> > devices with dead ones - swapping in from a working unit is a real pain.
> 
> Hmm, shouldn't be too hard with modern programmable-logic devices.

Was the Tube ULA (or the Tube interface) fully documented anywhere? 
Obviously a pinout of the ULA exists, as does a general description of 
what it did. And I think the source code to the drivers on at least one 
side were published somewhere (I seem to rememebr a book on the Master 
512 the contains such sources). But I didn't think there was enough info 
to necessarily correctly implent the ULA functions.

-tony