22 Feb
2006
22 Feb
'06
10:46 p.m.
Guy Sotomayor wrote:
On Mon, 2006-02-13 at 15:41 +0100, Gooijen, Henk
wrote:
The only problem with SPC slots is they are 18b UNIBUS only. This will
work on 256KB 18b machines, but is a sticky problem on 4MB 22b machines,
since you need to go thru the UNIBUS map to get to all of memory.
For an 11/44, you could do just a dual slot card that goes in a memory
slot (which has 22b address available) and an SPC slot (to get the DMA
lines) but this would be a hex card. To read/write memory, you would
need to be a 22b DMA device, which I'm not sure the 11/44 can handle
(ie, the CPU may always drive the upper 4 address lines and not provide
for 22b DMA device). It may work, it may not. Certainly not what DEC
designed for.
On the other hand, writing a bit of C-code for a PIC processor that
handles the console switches and talks to the ASCII console via RS232 is
a piece of cake.
--Don
Without thinking much about it, I'd say that
mounting any
real blinkenlight console on a 11/44 is *not* trivial!
Of course, grabbing UNIBUS address- and data-lines and wiring
that to the lights is trivial, but to get all panel functions
(LOAD ADDR, DEP, EXAM, etc). working on an 11/44 is more work
Not too much. I've got the basics worked out for any Unibus machine.
It won't be hard to adapt the approach to Qbus machines as well (but I'm
not up on Qbus at the moment). It should give you most (if not all) of
the capabilities of a "real" front panel
I guess there are more people on the list who
have a boring
PDP-11/44 with a dull panel, that would like to make the /44
more sexy with an 'appropriate' panel. The "upgrade" is,
of course, done in such a way that it can be undone ...
I (we) do not have a /74 panel :-( , but I'd like to hear
what approach you are thinking of, Don.
The approach I'm taking is to add an SPC board and then cables (ribbon)
over to switches and lights. Completely undo-able.