4 Oct
2015
4 Oct
'15
10:26 p.m.
You have no memory, and probably no devices to complete the
Unibus. So, it is quite likely showing the Unibus is in a
jammed state. At the least, you need a Unibus terminator,
and any bus grant cards between the CPU and the terminator
(you'd have to check the manual to see how the Unibus is wired.)
The specific issue of an open grant chain locking the Unibus is a quirk
of the M9302 terminator (which asserts SACK under such conditions). This
is unlikely to be a problem on an 11/10.
But you do need some kind of termination/pullups on the Unibus. At least
fit the CPU-end terminator (M930 in the right slot near the CPU boards) if
you haven't done so already.
-tony