27 Jul
2011
27 Jul
'11
4:14 a.m.
On Wed, 27 Jul 2011 11:31:34 +0200 (CEST)
Christian Corti <cc at informatik.uni-stuttgart.de> wrote:
No, a M930 is good enough for an 11/34. Of course, a
M9302 would be
better.
I know that the M9302 has some "SACK" logic in addition to
resistors,
wheres the M930 has only resistors. But I don't know what this logic is
good for. (UNIBUS is new to me.)
How did you connect your scope? Looks more like a
ground problem with your
measurement setup.
This could be the problem. I don't have an isolating
transformer. GND
of the scope and GND of the PDP-11 are connected to earth of the mains
plug. Because of this I connected both to the same power strip. I did
_not_ connect the GND clip of the probe to GND of the PDP-11. If I had
done this, I would have created a ground loop. This, of course, _will_
create problems. Without connecting the GND clip of the probe my
reference point was in the power strip.
But if the M930 is enough and if the voltages are OK, why can't I halt
the CPU with the control panel? There are NPR jumpers in the backplane
and grand cards in emty slots.
--
\end{Jochen}
\ref{http://www.unixag-kl.fh-kl.de/~jkunz/}