On Mon, Nov 6, 2017 at 9:59 PM, Tony Duell via cctalk <cctalk@classiccmp.org > wrote:
> Mine identifies the CPU as a 68010 in the power-on diagnostic. But from > what > I remember the PGA socket could also take a 68012 (with extra address pins > brought out). I don't have such a chip, so no idea what it would identify > as. > Do you mean that it will actually use the extra address pins? I suppose the most likely way for the software to identify the MC68012 (vs MC68010) would be to try accessing two memory addresses differing only in address bits A24 or higher (but not A30), and test whether whatever MMU hardware they've built will actually map them distinctly. The other difference in the MC68012 is the availability of a /RMC pin to better identify read-modify-write cycles, but since their board has to work with an MC68010, I doubt that it would use the /RMC signal at all. I've heard claims that HP used the MC68012 in some systems, but I've never seen any definite confirmation.
