Date   : Thu, 30 Jul 2009 12:38:52 +0100
From   : robert@... (Rob)
Subject: Tube questions

On 30/07/2009, Nick Balmer <corelki2@...> wrote:
>
> Does anyone have a circuit diagram for the "TUBE"
>

Which side?  Logically you could argue that the tube itself is just
the straight-through cable that links the two devices...  Practically,
there's only a little more than that involved!  The BBC side of the
Tube is minimal .. it's litle more than a connection to the bus and a
couple of address lines.  This links to a custom ULA within the second
processor unit, and that is mostly a set of FIFO buffers for trickling
data between the two processors.

There's a circuit diagram and lots of useful information in the 6502
second processor service manual, on Chris's site:
http://acorn.chriswhy.co.uk/docs/Acorn/Manuals/Manuals.html

You'll find the Model A&B circuit diagram in the same place.

Rob.