seeking Motorola M68MM01A2 documentation

Mike Katz bitwiz at
Tue Jan 18 14:01:25 CST 2022

I think it might be easier to modify the 680 prom for the I/O addresses 
of the board rather than modify the board to match the ROM.

Especially if the address decoding for the I/O is done in PAL (10L8 for 

Some 6800 address decoding was done with 74LS138s.  This had the 
potential to be inefficient in terms of memory usage or if the '138s 
were cascaded then propagation delay could become an issue.

On 1/18/2022 12:54 PM, Chris Elmquist via cctalk wrote:
> I have quite a few Motorola Microsystems Exorciser boards including this
> 6800 single board computer for which I am lacking any documentation.
> I've seen a brochure in Al's collection on Bitsavers but haven't found
> any details that might discuss jumper settings or even better,
> a schematic.
> Wondering if anyone would have a user manual or other detailed docs for
> this board?
> M68MM01A2 -- has 6800 CPU, 6875 1.0 MHz clock generator, 6850 ACIA and
> MC14411 baud rate clock, (4) EPROM/ROM sockets and (2) 6821 PIA sockets
> with the 86-pin Exorciser edge connector.
> I'm interested in seeing if I can minimally modify it to have a similar
> memory map to the Altair 680 so that the Altair's PROM monitor could
> run on it.
> Thanks!
> Chris

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