The board normally ran with an 8 MHZ clock with some 10 MHZ versions.
(Remember the clock in 6800x chips was ~2X the Intel chips). The two empty
sockets could accommodate 2716, 2732 or 2764 EPROMS in a high/low byte
arrangement.
The challenge for Motorola CPU's was there was no separate I/O signals.
CompuPro mapped the 256 I/O ports to addresses FF0000H to FFFFFFH. Only the
lower 8 bits were normally used. One unusual thing about the
board was CompuPro allowed the S-100 master clock signal (#24) to be
disabled by a signal on pin 21. This allowed slower slave processors to run
on the bus at a lower speed. The board also allowed up to 5 wait
states be put on the bus.
The 68000 had a built in seven level priority interrupt structure this made
splicing it to an external interrupt controller on the bus a little tricky.
CompuPro provided a few options on this board.
There was a large empty socket in the center of the board that was used to
add an optional 68451 memory management chip.
Apparently when Compupro was manufacturing it's CPU-68K S-100 processor
board. Bill Godbout never stopped grumbling about Motorola needing to get
their act together. Revision 184D was the first working production
version of the CPU-68K. Compupro revised the CPU-68K board over and
over again to try to get everything working (in particular the MMU).
Compupro laid out the socket for the MMU on the CPU-68K from the very first
version of the processor board, and kept revising the board as Motorola kept
changing the pin designations or the way that the chips worked.
Motorola eventually stabilized the 68K CPU and MMU designs which allowed
Compupro to finally offer the CPU-68K with a working Motorola MMU on version
184F (still needed blue wires), but at least the MMU could be installed, and
it would work (crippled).
Because the boards needed modification to make the MMU work, the
socket for the MMU was never supplied on board (unless Compupro installed
the MMU), People who wanted a working MMU would call Compupro for a RMA,
and the customer's CPU-68K (acceptable version) would have the MMU socket
installed along with necessary modifications to the processor board, and the
MMU would be installed and tested. That way Compupro had control over
the way the boards were modified, and the boards with MMU chips installed
would all work.
(Thanks Michael Louie for
this history info).
The schematic for this board can be obtained
here. The technical
manual can be obtained
here.