Date   : Mon, 25 Jul 2005 23:35:19 +0100 (BST)
From   : Pete Turnbull <pete@...>
Subject: Re: ARM copros, speech cartridges, real time clocks,etc

On Jul 25 2005, 22:32, BeebMaster wrote:
> I've been trying to find the Tube ULA (and other ULA) chips for years
but
> haven't found them anywhere.  I even had some enquiries made of
Ferranti
> at one point but they didn't have any old stock.

They wouldn't, since the ULAs were made to a contract for Acorn, and
Acorn had all the stock.  When Acorn ran out, and couldn't get more
from Ferranti, they got two replacements from other suppliers.  IIRC
one or possibly both was made by AMD; one is a pin-compatible and the
other isn't (it was used for internal co-pros, I think) and one was
bipolar and the other was CMOS.  Sorry, I haven't time to dig through
all the docs to find the sheet that says which is which.

However, the function and architecture of the ULA is documented, so it
would be possible to make a substitute from a PLD.  It's not even very
complicated.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York