Careful: the M9312 is for the CPU end of the bus, and besides the
near-end termination, it provides for diagnostic and boot ROMs, so it is
*not* a replacement for the M9302, but it's counterpart for the other
end of the bus.
As such, the M9312 goes into a MUD slot (*modified* UNIBUS device),
which has some pin designations differ from a *standard* UNIBUS slot,
which is the reason why the regular terminator (M930 or M9302) needs to
go into the last (=standard) slot, not anywhere in between. Hence, the
M9312 (designed for MUD slots) must NOT go into the last slot for the
same reason.
Further, there are some (five? W1 through W5?) jumpers on the M9312 that
connect pullup resistors to certain bus lines. There are CPUs for which
the jumpers need to be in, other CPUs have equivalent resistors on the
CPU boards, so the M9312 jumpers must be out for these. I don't have the
details at hand, but can look them up if you don't find the manuals
elsewhere.
Another near-end terminator and ROM board would be the M9301, but this
one doesn't have the pullup resistors. If the /44 needs external pullup,
you would be bound to use the M9312. ROM chips are NOT interchangeable
between the two boards.
Guy Sotomayor wrote:
> On Mon, 2003-02-10 at 07:29, Jay West wrote:
...
> The jumper is an M9202 (or M920 for the short one). The terminator is
> most likely one of: M930, M9300, M9302 or M9312. The terminator goes in
> the last slot of the unibus.
--
Andreas Freiherr
Vishay Semiconductor GmbH, Heilbronn, Germany
http://www.vishay.com
Received on Tue Feb 11 2003 - 04:52:01 GMT