--- Richard Erlacher <edick(a)idcomm.com> wrote:
It would have been difficult for them to do, since the
CPU didn't have that
capability. The Z80 had a hardware refresh cycle built into its operating
circuitry. It had a refresh counter (though only 7 bits) which was placed on
the address bus while the CPU decoded an opcode.
I realize that. I think what I was being told about was a refresh system
that depended on some line out of the CPU to tell when it was safe to do
a refresh cycle. The CPU locks up temporarily and blocks the refresh
accidentally until it recovers.
The microcode faults I was told about for the XC68000 (not MC68000) would
The XC68000 was the designator for the earliest units, primarily engineering
samples of the various masks...
Yes. My boss still has ours. It has a serial number (#424) engraved on
the lid. We were told that the first 400 were for internal Motorola use.
-ethan
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