30 Mar
2006
30 Mar
'06
10:29 a.m.
Tony wrote...
Fine. I was just making sure you'd connected it to a logic ground.
If the input signal is noisy, or something like
that you might get
spurious results.
It looked noisy to me!
What have you connected the ground lead of your
'scope probe to?
When measuring BUS LTC L at CD1, I used CC2 as my ground
reference. Just
before that I put the scope between CC2 and CA2 and got a nice non-ripply +5v trace. I should point out that the ground clip on
my probe is a bit
large for clipping to a backplane pin, so I used an alligator to microclip
extension that is about 8 inches long. Surely that wouldn't mess up the
signal that badly.
Not a 60Hz signal, no :-) And as you saw it's not even got a fast rise time.
[Where LTC L goes on the DL11-W card]
Good idea. The 7414 is at E45, CD1 goes in pin 9 (4a)
and out pin 8 (4y).
I'll ground the scope at pin 7 and see how the signal looks. If the issue is
Yes, I'll agree with that.
bit 7 in the RTC is not setting (according to the
diag), and I get a good
clock out of the schmitt trigger, I assume the next thing to check is the
pin 8 output of the flipflop the trigger drives? That seems to be where bit
7 comes from.
Exactly/
The interurpt logic does not require LTC L to
work.
Ok gotcha. I still suspect something with trap/interrupts being broke. But
more on that later :)