PDP-11/05-NC with M9301?

[Mattis Lind]

2016-03-17 17:27 GMT+01:00 Guy Sotomayor <ggs at shiresoft.com>:

>
> > On Mar 17, 2016, at 6:01 AM, Mattis Lind <mattislind at gmail.com> wrote:
> >
> >>>
> >
> > If one read notes in the PDP-11/04 printset it says: Do not insert a M930
> > or M9302 in a MUD slot. Only in the Unibus slots or you will have short
> > circuit. On the other hand it does not say that the M9301 (or M9312)
> cannot
> > be installed in a unibus slot. It recommends that those boards go into
> MUD
> > slots. But electrically I cannot see that it shouldn't work. Especially
> if
> > you jumper W1 - W5.
> >
>
> Hopefully this will clarify a few things:
> “Unibus”: These are the AB connectors in the *last* position of a
> backplane.
> It allows for bridging between backplanes.  The only “card” that can go
> these
> “slots” is a terminator (ie M930) or a terminator bootstrap (ie M9312).
>
> SPC: These are the CDEF connectors in any of the slots of a “unibus”
> backplane.
> Not all backplanes support SPC slots.
>
> MUD: These are the AB connectors in some newer backplanes (usually
> associated with
> the extra slots in a CPU backplane…11/34 and 11/04 CPUs have MUD slots).
> MUD
> stands for “Modified Unibus Device”.  They are *not* compatible with
> Unibus slots
> as they have different voltages present than what are on the Unibus
> slots.  You *will*
> “blow out” a board by plugging something designed for a Unibus slot into a
> MUD
> slot.
>
>
Yes. That is pretty clear from pin assignment list that bad things WILL
happen if you try to install a Unibus-slot-compatible device into  a MUD
slut. But the vice-versa? Installing a MUD-compatible device into a
Unibus-slot?



> TTFN - Guy
>
>
>
/Mattis