Date   : Tue, 14 Mar 2006 15:36:11 -0000
From   : "David Harper" <dl.harper@...>
Subject: Re: Web site: Mainly Master 512

Fragula wrote:

> The 512 was more or less where I "left off" the beeb (as there was a lot
> of misinformation as to whether it would even run on a B, I didn't bother)
>
> I might be "clocking" one over the next few months.. With the kids I've
> done the whole water cooling etc. overclocking PCs and doing a blog and
> photos about it thing... now its time to get back to basics. >;{> and
> what better way to start?
>
> I've gotten some nice fast DRAMs, looking for a tasty 80186-nn (faster
> the better providing its a pincompatible PLCC68) at the mo.
>
> Gonna invest in nice quality sockets and a few
> (24/28/32/36/40/44/48/49/50 MHz) crystals, or maybe work a variable RC
> replacment and use a counter to measure "best stable"
>
> Warm up the iron and have some fun! The 80186s come up fairly frequently
> so i'm not too bothered about desecration/blasphemy etc., and i don't
> think its got anything to break that can't be easily fixed anyway.
> Except maybe the Tube ULA.

Can't see any problem with this. The Tube is an asynchronous connection, so 
provided you go faster it should work. (You can't slow it down too much, 
because the host expects data transfers to have a minimum guaranteed speed.) 
There will, I think, be a limit. The Tube ULA will require some time to give 
up its goodies, or to accept bytes written to it. You may get some 
unreliability as you approach this point.

Perhaps someone on the list knows the electronic requirements of the Tube 
ULA chip and its response times.

The "Technical Guide" has a clocking project in one of the appendices, but 
it is only about putting a slightly faster oscillator to speed up all the 
other components. It sounds like what you are planning is more extensive.

David