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SYS68k CPU-6A rev 4.4 Force Computers

tonata

Experienced Member
Joined
Sep 11, 2019
Messages
190
Location
France
Hi,

I have this SYS68k/CPU-6A rev 4.4 board. It uses VMEBus.
Can I make a computer out of it? And connect through serial port to it?
If I can power it on and make terminal only computer, it's still something.
I have no idea what OS can run on it.

Specification:
• 68000 CPU ( 8MHz) on CPU-6 68000 CPU (12,5MHz) on CPU-6A 68010 CPU (12,5MHz) on CPU-6VN6VB
• 512 Kbyte of dynamic RAM o Wait States at 8MHz 1 Wait State at 12,5MHz Distributed hardware refresh every 15us
• 4 EPROM sockets provide 256 Kbyte space
• 3 serial communication ports (RS232 compatible)
• Parallel I/O interface to P2 connector
• Real Time Clock with on-board battery back-up
• 24-bit timer with 5-bit prescaler
• Local interrupt service via auto-vectoring
• Fully VMEbus IEEE 1014 standard compatible
• RESET and ABORT function switches
• Double Eurocard from factor
• Powerful real time Monitor/Debugger VMEPROM on board
• PDOS' Real Time Operating System optionally available
• Fully software and I/O signal compatible to the SYS68K1CPU-1 B series
 
Can I make a computer out of it? And connect through serial port to it?
Manual is here if you hadn't found it.
https://www.artisantg.com/TestMeasu...PU-6A-SYS68K-Single-Board-Computer-VME-Module

It does have serial monitor on the board. I think the monitor will allow uploading code to it. Doesn't seem to have any interface to mass storage on board. You would need to put it in a VME chassis with floppy or hard drive controller board to get storage. Finding operating system that will work with it could be a challenge.

I did use VME bus stuff many years ago though not this board.

Don't seem to be too many people collecting industrial stuff like VME.
 
At my first job after university I had a rack of force 68k systems positioned about 2 feet behind my chair, thankfully they were turned off most of the time. From memory they were running OS/9, some had disk drives others ran from rom.
os9_68k_sdk

I don't think the card has an mmu, so if you attempted to run linux you would need to use the nommu option when compiling the kernel.
 
First thing to check: are the original EPROMs with the VMEPROM monitor installed?
Every CPU-6 board contains VMEPROM, a realtime multitasking monitor debugger.
It consists of a powerful realtime kernel, a file manager and a monitor/debugger with 68000/68010 lineassembler/disassembler.

Normally, you need a VME rack to test the board, but you can try something like this with a PC ATX power supply:

vme.jpg

I have no idea what OS can run on it.
The board doesn't have a SCSI controller, so it might be a bit difficult to run an OS.
It should be possible to install an OS-9 kernel in EPROM.
 
Here is a photo of the 4 eproms:

eproms.jpg

The VMEPROM should be on one of the 4 marked SFCSMA06 ?
 
Can you please comment on the EPROMS? Do you have an idea what these markings can be? Probably some custom ROMs?
Just to test if the card works I will need to:
- powered it on
- see if these EPROMS output something on one of the serial ports
?

Can I download a VMEPROM?
 
@tonata I have the same board and the ROMs are marked very similar to yours.

cpu6a-eproms.jpg

Dumping the original ROMs it appears to be a custom PDOS application produced by or for Alphasem.

I've been unable to find copies of the original VMEPROMs. If you find them I would like to get a copy.

Good news is the ROM monitor and debugger for the SYS68K/CPU-1 board seemed to work on the CPU-6A, at least I remember being able to load Motorola hex files and dump memory. I found the ROMs referenced in the mame SYS68K/CPU-1 driver source.

The monitor command summary can be found on bitsavers, http://www.bitsavers.org/pdf/forceComputers/brochures/Force_SYS68K_MONITOR_Brochure.pdf
 

Attachments

  • force_cpu1_monitor.zip
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Thanks jxm.
Looking at the documentation the names of my ROMs are: J14, J19, J73, J54.
Do you know what is the execution order of the ROMs? Which ROM is loaded first? Is the second loaded automatically? There must be some organization/standard for that.

I found this thread: https://forums.bannister.org/ubbthreads.php?ubb=showflat&Number=110968
It is 19 pages and here and there are some very useful bits I think, but I need time to check it out.
 
Looking at the documentation the names of my ROMs are: J14, J19, J73, J54.
The CPU-6A EPROM sockets are J75, J76, J77 and J78. The ones you reference are for components underneath the EPROMs. The EPROM Area 1 and 2 diagrams highlight the EPROM locations and designators. These are figures 4.1-2 and 4.2-1 of the document @djg pointed to in the first reply.

Do you know what is the execution order of the ROMs? Which ROM is loaded first? Is the second loaded automatically?
The EPROM address mapping along with other memory device specific information is covered in "Section 4.0 THE LOCAL BUS". Basically on reset the initial stack pointer and program counter are read from offsets 0 and 4 of EPROM Area 1 (J75 and J76). The physical address of Area 1 offset 8 is 0x080008. Addressing and device compatibility for Area 2 are also covered in this section.


I do not know where the J8 and J9 designations that are part of the EPROM image filenames are from. These are not the EPROM socket numbers of the CPU-1B documentation that I've looked at. They work none the less and I'm happy to have them.

The archive contains images for 2 separate programs, Force Monitor and Force Debugger.

Descriptions from the mame sources are:

"Force Computers SYS68K/CPU-1 Force Monitor 1.0L"
fccpu1v1.0l.j8.bin
fccpu1v1.0l.j9.bin

"Force Computers SYS68K/CPU-1 Force Debugger 1.1"
fccpu1v1.1.j8.bin
fccpu1v1.1.j9.bin

On the CPU-6A the J8 image goes in J75 and the J9 image goes in J76.

installed-eproms.jpg

I've found that VME boards tend to be highly configurable and setup can be a challenge even with documentation.

If you are not familiar with the Motorola 68K processor or the VME bus I would recommend reading some introductory material on both. I do not have a list of these documents to share. Maybe others can recommend some titles.
 
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