Need Motorola M68MM01A Monoboard Micromodule 1A manual

[Bruce Tomlin]

I picked up one of these boards at VCFSW and it would be nice to have the proper schematic for its ports without having to spend time tracing out the circuit. Unfortunately the one that has been scanned is for a different version of the board, and it is significantly different. (3xPIA vs 2xPIA+6850, and the pins wired up differently)

There's someone on ebay wanting fifty bucks for one, and that's a crazy talk price, but at least now I have a nice picture in case someone recognizes it lying around in their piles of manuals.

 

[stanleyruppert]

Here is a quick scan of my manual covering both the M68MM01A and 01A2 revisions. Fun and capable board to experiment with.

M68MM01A-D3.pdf

drive.google.com

RS232 is on the 20 pin connector. Pin 1 is GND, Pin 3 (in) is RXD, Pin5 (out) is TXD. Schematic Labeling relative connected terminal.
Stock boards assume DTA Term Ready on pin 14 is used and it passes through U23 on to 6850 /CTS.
If you are using only three signal rs232 (TX, RX, GND), add a 4.7K pullup from U23 pin 10 (VIA near R20) to +12V (E16 is +12V).
Many boards I have already had such pullup installed. See the schematic for details and text for other configuration jumpers such as baud rate etc.

Have fun.

Stan

 

[Bruce Tomlin]

Thanks! I don't have any problem knowing what to do with it, just how the thing is wired up. The other version with three PIA chips looks like it's set up for putting terminating resistor packs on every PIA pin, which is just bonkers, but that's how I can tell that it's not just a minor difference.

And I love that ridiculously oversized clock module. It even has an MC68xx series part number: MC6871A

 

[epooch]

I finally picked up one of these. I liked that it was a real MC6800, not MC6802 and it has a super simple layout. I’m excited to get it up and running. Thanks for the manual Stanley!

 

[Bruce Tomlin]

FYI this was the part that I ordered for the big edge connector. The pins seem to fit into those female "dupont" connectors that are used for Arduino-type projects. (I didn't check beyond fit, as I won't have time to do anything with it for quite a while because of other projects I have going.)

https://www.amazon.com/dp/B0CM8MJC2R

 

[epooch]

I can give you a better deal on 86 pin connectors if you’re interested. Either PCB or wire solder type.
Since the ground and +5 the pads are the same on both sides you can use alligator clips on the pads to get it running too.
Do you have any plans for your board yet? I’m still trying to figure it out. I’m thinking maybe a little rs232 Terminal with keyboard and character LCD on the PIAs.

 

[Bruce Tomlin]

I'm planning to rig up an adapter board to make it work with a MEK6800D1 keyboard (because of course there was no reason for Motorola to ever use the same pinout on two 50-pin edge connectors to a PIA), then try to add a 32K SRAM. I have two of those and I'd like to hook up the other to a M68HC11EVB. I'd probably do the HC11 first since it's already working.

What I really want to do is set up the HC11EVB with a big SRAM, but its expansion connector is designed only for I/O ports, not the bus, and its memory map is kind of crap. What I'll probably do before much of anything else is get a DIP HC11 hooked up with a bus. An 0.1" header version of the SWTPC bus would be nice, but I'm not going to have that kind of free time for a couple of months.

 

[epooch]

That sounds like a good project! I was pondering SRAM myself, but the the micromodule sockets are definitely not set up for that. Nothing a few bodge wires can’t fix!

Here is some EXORbus MC68HC11 goodness for you: