9 Nov
2015
9 Nov
'15
11:19 p.m.
On 11/9/2015 7:31 PM, Noel Chiappa wrote:
Brain fart, I meant IDC
ribbon cable.
From: Jim
Stephensn
The 9400-YE has the cables that formerly went to
the 11-780. I'm not
sure what it does. ... I'm not sure if the M9400 needs to be pulled or
not to run the system.
This one I actually can answer, since I've been looking for /780
documentation: found some, but nothing on the hardware config of the console
front end, alas. But I did discover about how the LSI-11 is interfaced to the
VAX!
The M9400-YE is a standard QBUS card for doing QBUS extension boxes; the QBUS
leaves the M9400-YE (at the end of one box) on a couple of cables, which
normally go to a M9401 (the sister card to the M9400) in the first slot of
the next box.
In the /780, the cables from the M9400-YE instead go to a card in the VAX
CPU, an M8236 (the CIB - CPU Console Interface Board, I think). That board
contains i) a bunch of ROM for the LSI-11, and ii) registers which allow the
LSI-11 access to the inside of the /780 CPU - all of which are actually on
the LSI-11's QBUS, logically/electrically.
So, as to the M9400 - you can pull it, or leave it - there are no active
components on it (although it does have termination pull-ups). Do pull the
cables, though - they'd be un-terminated antennas...
The M9400 seems to possibly be the Floppy boot
and some other logic.
There are some versions of the M9400 which contain ROM chips with a
bootstrap. The M9400-YE, which you have, does not have these; it only has the
headers for the cables, and the pull-up resistors.
> The line below that I clipped out, about the M7940-YA is for the
> adjacent card, and has no cable, just the open blue one waiting for an
> IDE cable to the back for serial connections. Err, it's not an IDE cable, although it is a
40-pin connector; it is used
with special round cables, the wiring of which I described in an earlier
message.
I'll pull
and play in the next few days and post an update on that
part. Also will pull the antennas. :-)
thanks for the help.
I also have a buddy rummaging thru his pile for a sigma type box with a
similar configuration which will help as well. His may have what you
suggested, the 4 port card and a cable I can copy (or abscond with).
One reason I asked here, you answered about finding the cables on ebay.
Explains why I've not been able to stumble across any. But the buddy
mentioned above did a lot of dec maintenance and put these cables in a
pile as he found them.. Problem again the cleaning and searching job
right now has not turned up that bin box either.
However it will turn up.
I'm also watching Mike Ross play with an Altera Spartan board and he is
going to try to get the 2030 emulation going, It may motivate me to get
off my thumbs and get out mine as well while my buddy searches for cables.
Also will order some parts to make the cable off the M7940.
Thanks again
jim
A post by Tony Duell some years back states that
the M7940-YA may have
both a current loop and RS232 drivers for the port. That ... might
explain the puzzling extra bit in the Dec module description about
extra wires.
No, the stock M7940 _already_ has support for both EIA and 20mA; see the
DLV11 prints (MP-00055), pg. 6; the EIA stuff is in the top right-hand
corner, the 20mA in the bottom right-hand.
On that same page, lower left, note the baud rate clock generation; note
that's entirely set by jumpers, so if there's some off-board way to set
it in the M9740-YA, they must have modified this area of the board. Noel