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Edstrom, pmackinlay, R. Belmont, Revenant
Total Likes: 6
Original Post (Thread Starter)
#101333 08/28/2015 8:11 AM
by Edstrom
I'd like to discuss VME boards here. VME based systems are highly modular and was introduced early 80ies as a standardized continuation of Versabus. At first only 68000 family was supported but over the years many CPU types and i/o boards were adapted and the latest standard even support 64bits aka VME64. I intend to contribute drivers for a few early ones suitable for emulation. If you sit on information or ROMs fitting this description please let me know.

First out is Force Computers CPU-1 for which I have just filed a pull request. Or you can grab it at branch m0165_fccpu1_3

layout files and instructions are found here:
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#119929 Oct 28th a 08:03 AM
by Luigi30
I'm working on a driver for the Motorola SYS1121, a combination of an MVME120, MVME050 SYSCON, and a disk controller. I can get the MVME120, as a slot device, booting to the 120bug console with a little poking in the debugger (it doesn't fully pass one of the exception tests during a cold boot, but I can bypass it.)

[Linked Image from]

I'd like to try to hook up the bus logic and get it talking to another card in the VME address space but I'm not sure how well the VMEbus emulation in MAME works, or if it works at all. It doesn't look like it's hooked up in any of the other VME slot devices.

The firmware and manuals are all on Bitsavers and m88k. Unlike the later MVME SBCs, the 120’s bus logic is all in PALs and TTL.
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#120078 Nov 23rd a 04:48 PM
by Luigi30
Yeah, I’ve been working on improving the bus emulation, particularly the address map stuff using the new hook system. In my branch, I have an MVME050 SYSCON card that installs itself over the entire VME address space. It acts as a memory bus device of last resort, asserting /VBERR on access after the bus timeout period if no other slot device is overlaying an address. All slot devices pick that up and fire the appropriate callback. This is good enough to get the 120bug firmware to think there’s an 050 available (though I don’t have bus interrupts hooked up yet…)
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#120207 Dec 20th a 11:25 AM
by shattered
besta.cpp is now bus/vme/vme_cp31.cpp. It was probably a customized version of Force CPU30 series board. There are some technical manuals in Russian, but no schematics.

HCPU30 board is more interesting, as it has onboard SCSI and Ethernet supported by MAME, a Linux 2.0 port with source, and schematics (but no PAL dumps). It needs significant updates to DUSCC emulation, some changes to DP8473, to NSCSI HD device (1024-byte sector buffer instead of 512) and probably more, as Unix and Linux weren't stable when I managed to boot them. I am trying to untangle my wip DUSCC code now smile
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