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Date   : Wed, 03 Mar 1999 17:51:18 +0100 
From   : "Nooijen, Hubert SSI-TSCO-2" <Hubert.W.Nooijen@...>
Subject: Re: The TUBE, etc.

A more and wilder guess:

Suppose that the Tube ULA is the same device in both second processors.
Suppose also that we replace the Z80 CPU and Tube EPROM with the
corresponding 6502 stuff, ensuring that the 6502 CPU is able to run at the
Z80's 6 MHz - or failing that, some tweaking on the PCB to bring the clock
speed down to 3 MHz. What would happen? Do we get a working 6502 2nd
processor which possibly is the fastest around at 6 MHz? Or do the CPU and
ULA get fried?

I think there's a good chance that it works (it would be *really* nice too,
because I can then perform some body building on my Z80 2nd processor to
have a 'fast' 6502 system with more memory!). Why reinvent the wheel if you
can use the same basic design for each different second processor, just what
Acorn presumably have did?

Hubert N.

> ----------
> From:     Fraser, Colin J[SMTP:Colin.Fraser@...]
> Sent:     03 March 1999 16:15
> To:       bbc-micro@...
> Subject:  [BBC-Micro] The TUBE, etc.
> 
> Is the Tube ULA in the 6502 second processor the same device as the ULA in
> the Z80 second processor ?
>  
> I've got a Z80 second processor, but I'm sure second processor Elite will
> be
> more fun than playing with CPM.
> If the ULA is the same device, and there are no other hard to find parts
> in
> there, maybe I can rig up a 6502 second processor unit.
>  
> Alternatively, if someone has a 6502 2nd proc. with a knackered ULA they
> want to part with...
>  
> On anothre subject, can someone confirm the wiring for the 9 pin RGB
> analogue video plug on my old Archie, before I blow something ?
>  
>  
> Colin f
>  
>  
> 
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