[rescue] Anyone Familiar with VMEbus?

Mouse mouse at Rodents-Montreal.ORG
Fri Sep 17 13:44:35 CDT 2021

>>> [...PUMA arm...robotics control...]
>> I don't recall what we were using for interface hardware once it
>> left the host system (I wasn't dealing with it much past that
>> point), but I *think* there was no VME anything involved.  [...]
> Building new control hardware for PUMA robots is a favorite college
> project, it seems.  Lots and lots of college robotics courses do
> exactly that, with that hardware.

Nice!  That must be fun for the hardware hackers.

This grad student's work was more about the software, though.  There
was hardware, but the point was to run the control loop on the host.
This being the late '80s, we didn't have now-modern hardware for it; we
were using Qbus MicroVAXen (hence the finding a bug in the KA630), one
of the (I gather) few sites actually using multiprocessor MicroVAX-IIs
(one CPU for the host OS, the other for the real-time low-level control
loop).  I don't recall much about the interface electronics we used,
but IIRC the OP said something about wanting to talk to the arm with a
VT420.  If so, that means not just the minimal interface electronics we
had but some smarts - we wanted the interface from the host to the
robot to be about as dumb as possible, since the whole point of the
research was the control software.

My memories are thirty years old and somewhat fuzzy, but I _think_ we
used a hand-built Qbus board as the interface hardware.  I don't recall
how much there was between that and the motors, but there must have
been some driver transistors at a bare minimum, because I'm fairly sure
it was still logic levels when it left the host enclosure.

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