Motorola MEK6802D5

From: Arlen Michaels <>
Date: Thu Feb 26 15:19:00 1998

I remember building embedded control systems with these D5 cards back in
the early eighties. You are right, it is an evaluation system,
but it was often used for simple prototypes and small production runs.
Motorola priced it relatively cheap so engineers could gain familiarity
with the 6802, which was an "update" of the classic 6800 processor. The
6802 incorporated the 2-phase clock generator circuitry onchip-- you
used to have to add a nuisance clock circuit to make the 6800 run. I
think the 6802 also included 256 bytes of RAM (but my recollection's
fuzzy on this point.) Since the board also included a little
debug/monitor program in PROM, using that hex keypad and display, you
could learn a lot about the instruction set just by hooking up a power
supply and playing. It was a lot like the KIM or AIM-65 boards for the
6502 cpu.

Does the D5 have a large set of edge connect fingers (like, say, 86
contacts or something like that)? I can't remember...
Other Motorola evaluation kits, like the D2 (a predecessor of your D5,
also based on the 6802 cpu but built as 2 boards--the keypad was
separate) had a full electrical interface to Motorola's ExorBus, which
was their proprietary general-purpose microsystem bus. They made a full
range of heavy-duty industrial boards for ExorBus, and their development
systems used it too, so you could build full-blown microsystems with
their board sets. This was a competitor to Intel's Multibus in the
industrial control market. You could take a D2, when you got tired of
playing with it as an evaluation system, detach the keyboard, and plug
it in to an ExorBus as the cpu card.

It's barely possible I've got some old docs hiding at home... I'll check.

Ian McLaughlin <> writes:
>Hello all,
> I just aquired a "Motorola Memory Systems MEK6802D5" single board
>computer. It appears to be a 6802 evaluation or prototyping unit. It
>has a hex keypad and a 6-digit HEX display. In my old Motorola
>literature, I can find a reference for a MEK6802D3 from 1979, which
>appears to be an older version of this. The date code on the chips
>places it at circa 1980.
>Does anyone have any information on this unit? Any idea where I can get
>any documentation or programming info? It appears to be fully functional
>(at least, I get a display, and I can page up and down through memory
>examining and changing contents, etc).
>Any info would be appreciated.
Arlen Michaels
Ottawa, Canada     (613) 763-2568 
Received on Thu Feb 26 1998 - 15:19:00 GMT

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