Date   : Wed, 26 Aug 2009 15:01:29 +0100
From   : darren.grant@... (Darren Grant)
Subject: Tube FIFO

On 26/08/2009 14:51, "Jason Flynn G7OCD" <flynnjs@...> wrote:

> Upon reading the Acorn application note 004 (Tube) I note
> that at one point it says the large FIFO will be at least 10
> words deep and then the schematic shows 24.
> 
> Can anyone give any information on:
> 1) What size the large FIFO in a real Tube device actually is.
> 2) Whether a different FIFO size (say 8,16 or 32 words deep)
> would have any major impact on performance/compatibility.

I can't see any problems with a larger FIFO as the purpose of it is to
prevent the co-processor having to wait when accessing the host, the faster
the co-pro the bigger FIFO the better really otherwise it will spend a lot
of cycles waiting. The performance of the co-pro is largely dependent on
what it is doing, if you are running something that is continually writing
to econet for example it will inevitable end up waiting. If the process is
largely local like crunching numbers then the co-pro can work at its
fastest.