Date   : Wed, 05 Mar 2008 08:39:35 -0600
From   : jules.richardson99@... (Jules Richardson)
Subject: TUBE chip, accessing 'Parasite' side - 16Mhz 65C02S

Johan Heuseveldt wrote:
> David,
> 
> On Wed 05 Mar, David Warrington wrote:
> 
>>> The Master CoPro is 4 MHz!
>> The *internal CoPro* upgrade is 4Mhz. The external cheesewedge is 3Mhz.
>> I've  been keeping my eyes open for a 4Mhz board on ebay as a donor board
>> to  upgrade/replace an EXTERNAL 3Mhz 6502 CoPro.
> 
> It can be a bit confusing. A CoPro is internal for the Master. A Second
> Processor is therefor external by defenition. That is, the name Co-Processor
> was new when the Master Series came out. Before that it was only Second
> Processor.

Some external 32016 256KB/1MB cheese-wedges for the BBC (the "small" 32016 
board) are branded as "Cambridge Co-processor" whilst others are "32016 Second 
Processor" (although, oddly, I think the PCB silkscreen only ever says "32016 
second processor").

I don't have a definitive answer for when the 32016 "small" boards existed, 
but going by IC dates, the pre-release boards seem to be using parts from 
early 1984, whilst the "production" boards are late 1984 / early 1985.

I don't think the Master existed until late 1985 / early 1986, meaning that 
the term "co-processor" existed in a BBC micro context at least a year before 
the Master did.

> My reference to the Master CoPro being 4 MHz, should be unambiguous. :-)

In a Master context, wasn't there only ever an internal 65C102 co-processor, 
and never an internal 6502 one? Similarly, weren't the boards designed for the 
external TUBE interface only ever 6502 CPUs, not 65C102?

> About the replacement; the internal one is quite different in PCB layout,
> as it has two smaller connectors far apart from each other. An extarnal
> has a single connector, 40 pins flatcable for the TUBE connector.
> So you /do/ need something here to do ypursel. Or...
> 
> There is a(n external) CoPro case - by CC I think, specificly designed to
> do exactly that!

I had a Watford one (I think it went to Dave Moore), but I think that was more 
about the ability to run the Master-series internal boards (primarily the 
80186) on a lowly model B.

cheers

Jules