27 Jul
2009
27 Jul
'09
11:55 a.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Tony Duell
Sent: Monday, July 27, 2009 11:14 AM
To: cctalk at classiccmp.org
Subject: Re: PDP11/34a resurrection help
One thing that would help you a lot with the console cable: check out the prints for the
DL11 (M7800) on Bitsavers (thanks, Al!). It has a table of the connections, including the
jumper Tony mentions. These cables aren't all that uncommon, so you might be able to
pick one up on ePay or from someone on this list. -- Ian
I've got the DL11-W set up in the same manner
as the 300bps example
in the
11/34 Users Manual (and the DL11-W Operators
Manual), and at this
time I
have the three X* cards as well as the M7843 card
removed as I don't
believe they're required for boot.
With na M9302 terminator at the end of the Unibus (as you have), that's
going to cause problems. Basically, there are 5 signals known as
'grants'
that are not bussed, they are passed from one card to the next along
the
backplane. If there's a gap (as there will be with cards removed),
there's soem logic on the terminator that gets confuesed, and hangs the
entire machine.
I can give you a lot more details if you want it. To start with,
though,
youshould be able to run a short Unibus like that with no termintor at
the far end -- just pul lthe M9302 card as well.
I've verified on the backplane that +5 sits at a steady +5.06VDC and
-15
is at -14.86VDC. I do not possess an o-scope, so
the best I can do is
with
my multimeter.
I have two problems. The first is that I do not own a "proper" cable
that
goes from the DL11-W to a terminal. I own a VT240
and have crafted a
cable
that goes from the Berg connector on the DL11-W
through a header to a
DB9,
which connects to a DB25/DB9 expander on the back
of the VT240.
Obviously I've verified the VT240 is in 300/8O1 as required. To go
from
the flat-ribbon to the DB9 I have what used to be
the header from a
CDROM
drive and have soldered the RX/TX/GND lines on
the DB9 direct to the
pins
on this header. Currently it looks like this:
BERG DB9
B 5 GND
F 2 RX
J 3 TX
I -think- this is right, but I'm not positive. If I'm doing something
stupid, I'd sure love to have someone point it out.
I think there's one thing you've forgotten, but it would only affect
input from the terminal. And that's that you need a jumper wire on the
Berg connector to connect the output of the RS232 receiver (for the RxD
line) to the input of the UART (the reason for this jumper is that you
can fit a different jumper to connect the current loop circuit to the
UART).