30 Aug
2014
30 Aug
'14
7:37 p.m.
Yes, 'JTM' is in fact correct - that's what the seller stated in the
listing. I was just following your lead, and didn't notice the typo.
And again, per the seller, that photo on my ~legendre site is supposedly
the selfsame board which I am receiving. Looks to be in very nice cosmetic
shape, hopefully it didn't suffer electronically at some point.
On Sat, Aug 30, 2014 at 8:04 PM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
On 2014-Aug-30, at 1:36 PM, drlegendre . wrote:
Message from me of 2014 August 27 1:45:56 PM PDT.
same
Correcting myself .. JTM.
If that photo on your site is the actual instance which you are to receive
then yes, they look quite the same.
Except the 5 CTS switch blocks on the photo instance have reversed on/off
positions to the one I have (and from the manual).
I was just playing with the one here to get it working.
On Sat, Aug 30, 2014 at 2:49 PM, Brent Hilpert
<hilpert at cs.ubc.ca>
wrote:
Earlier
in the thread:
Really, where? In this thread? Hmm.. don't see it. > Nothing else in the system should be
asserting phantom so it shouldn't
> matter whether the phantom jumper is installed, but you could remove
it to
be sure.
(Sec 1.7)
I was wondering about Phantom.. as yes, it does seem to duplicate the functions as banking. But it seems that Phantom
is only used upon reset,
or
power-up, to +temporarily+ overlay boot code
which then "disappears" for
the remainder of the session once it's served its purpose and the phantom
line is released.
So then, asserting Phantom when the system is operating has no effect -
correct? It only acts after a reset event? It would be like the action
of a
J-K lfip-flop - the J/K lines cannot change the
state of Q on their own,
they only determine what value Q will take on the rising-edge of the next
clock cycle (the reset event, for phantom).
Do I have that right?
Generally speaking yes. On system reset, some flip-flop on a PROM board
would be set, enabling the PROM and asserting phantom on the bus, to
disable a RAM board so the PROM can overlay it. Some subsequent action
during boot would trigger the PROM board flip-flop off and de-assert
phantom so you now had full RAM available.
But the RAM boards are passive responders to the phantom signal, there's
nothing prohibiting a system design or PROM board design from reasserting
phantom at a later time under some program action.
> Going from what I'm seeing you may have
to be careful to note the
> open/closed orientation of the switches, as it appears the installed
> switches aren't always consistent with the config diagrams in the
manual.
Yes, duly noted.. I saw that.
> I actually have the JTS version of that board
(same board marketed
under a
> different name).
The board
I'm receiving is marked JTS on the rear.. so I guess we've got
the same
one!