MC68020 Bus - Page 1
Forum section: electronics / general

author: UPI
author_rank: Regular Contributor
timestamp: September 28, 2013, 08:23:25 pm
content: Is anyone familiar with the bus shown in the attached pic? I believe it runs CP/M on the MC68020 processor.I was hoping for clues on how to reverse engineer this system so that I have access to lower level operations.Thanks

author: legacy
author_rank: Super Contributor
timestamp: September 28, 2013, 08:37:13 pm
content: i did a lot of 680x0 hw, but it's the first time i see something like that. I worked with DTACK bus and VME bus. Sorry, no idea

author: UPI
author_rank: Regular Contributor
timestamp: September 28, 2013, 08:41:53 pm
content: It had been referred to as a Motorola EXORciser bus by a former co-worker, but I am not sure he was correct.

author: dfmischler
author_rank: Frequent Contributor
timestamp: September 29, 2013, 01:58:13 am
content: You will notice it only has 16 address lines and 8 data lines (unmarked in your attachment), so not very useful for MC68020 (32 bit CPU).I would be willing to believe that it could be theMotorola Exorciserbus. My experience with this in the early 1980's was with MC6800 family processors. You didn't run CP/M (that ran on Intel 8080 or Zilog Z80), but Motorola had a simple 8" floppy disk based operating system. I can't remember what they called it. But it sucked. I built a simple board to support additional debug functions including downloading code from a minicomputer with a cross assembler and linker and just used the Exorciser chassis to operate the ICE module... Life is much better with real editors and backup facilities and being able to share files on real disks..

author: Hardcorefs
author_rank: Regular Contributor
timestamp: September 30, 2013, 12:19:03 am
content: Actually CP/M DID run on 68k processors.I had a complete development environment , it was for the SAGE range of hardware, I had to reverse engineer the kernel to run on the old ATARI ST.Specifically SAGE went tits up, and we required a more modern system to run our development environment on.The good thing with CP/M was that you only needed to provide very simple kernel patches to get it to run on other systems of the same CPU design.

author: dfmischler
author_rank: Frequent Contributor
timestamp: September 30, 2013, 12:42:58 am
content: Quote from: Hardcorefs on September 30, 2013, 12:19:03 amPerhaps it did. But I am talking about Motorola's 8-bit mpu family: MC6800, MC6801, MC6802, etc. that were supported by the Motorola Exorciser. Note the missing zero to make it a 68000.

author: digsys
author_rank: Unknown
timestamp: September 30, 2013, 01:28:27 am
content: I still have an Orion emulator with the 680xx pods. I'm pretty sure it's still all there.If it's useful, maybe we discuss further. I loved the 680xx series, long ago.

author: UPI
author_rank: Regular Contributor
timestamp: October 01, 2013, 02:20:14 am
content: Quote from: digsys on September 30, 2013, 01:28:27 amThanks for the input. I just wish you were near Dallas and had nothing better to do.I really wouldn't even know where to start with the emulator since I am not a software kind of guy. I will have to get my brother involved to see if he could make sense of it all.FYI - This is a piece of industrial manufacturing equipment that has been in production since the early 70's. There are thousands of various vintages still in use. It started out using a 68008 CPU and changed to the 68020 when the 008 became scarce.It originally drove an XYZ stage and material handler using just this bus/cage and misc. driver and communication boards. In later models, they added a PC but kept this card cage driving the XYZ hardware.I have built 2 different add on diagnostic boards for this machine. I would like to learn more about the 68020 side so that I can create new add ons that either listen or talk on the bus, but I may be in over my head.

author: Stonent
author_rank: Super Contributor
timestamp: October 01, 2013, 02:53:29 am
content: A lot of non-PC (Not a mac, Atari, or Amiga) systems based on the 68K series processors used a bus called VME. I have no idea if that is this implementation as I don't know the electronics behind it, but it is one more possibility to look into.http://en.wikipedia.org/wiki/VMEbus

author: legacy
author_rank: Super Contributor
timestamp: October 01, 2013, 05:16:11 pm
content: Quote from: digsys on September 30, 2013, 01:28:27 amwhich software does it run ? I am interested about finding something similar on ebay

author: digsys
author_rank: Unknown
timestamp: October 01, 2013, 10:36:34 pm
content: Quote from: legacyIt came with 3x 51/4" Floppies :-) and big shiny box. I found the 68000 pod, but not the others yet.It runs it's own IDE, you unplug the CPU and plug in the pod cable. Also has 48 IO triggers.IF you can't find any info, I'll dig up what I have, it was very popular in the old days.Seeing as I'll never use it again, I can make you an offer - original cost with pods $14K, your cost $postage !