6502 CPU schematics

[Steven Hirsch]

On Sat, 8 Mar 2008, Roy J. Tellason wrote:

> On Friday 07 March 2008 17:34, Tony Duell wrote:
>>> Thinking back a homebrew computer ( with a change in the cpu card) was
>>> in BYTE a 6800 or a 6502 machine.
>>
>> The 6800 and 6502 buses are indeed very similar, so this does not suprise
>> me at all.
>>
>> I think the UK-designed Tangerine machine had a CPU card with overlapping
>> 40 pin IC pads for either a 6800 or a 6502 (you had to change the monitor
>> ROMs as well, of course).
>
> Which reminds me,  does anybody else remember those machines that had multiple
> CPUs in them?  Or the option of plugging different ones in?  Seems to me real
> early on there were some mfrs trying to find as much compatibility as they
> could with pursuing options like that.  I remember one Taiwanese-made clone
> of an Apple II that had a Z80 on the main board,  and of course the c128 has
> that similar setup (though the way the hardware was structured the z80
> effectively ran at something like 2.5MHz).  I remember some other system
> where you could literally plug in different processors for different uses,
> but the brand name isn't coming to mind at the moment.

That may be the Dimension 2000.  I have one in my collection, along with 
the Z80 and 6502 CPU boards.  Always wanted to find the rarer board that 
used a National Semi 32?? something to run an earlier version of Unix.



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