Searching \ for 'weird stuff happens...' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=weird+stuff+happens
Search entire site for: 'weird stuff happens...'.

Truncated match.
PICList Thread
'weird stuff happens...'
1997\05\21@114503 by Ben Roothooft

flavicon
picon face
Hi everybody,

First of all, to everybody who replied to my
last call for help THANXXX a lot (Dennis,
Mike,...) !

Here are some questions for all you experts
out there...

1) When I look at the OSCOUT pin of my 16C74
  I see the following sine : 1 to 2 Vpp AC
  and 2.5 V DC. Is this normal or should the
  signal be larger. (Is the DC voltage OK ?)
  What could be the problem ?

2) Very strange, the next one ...
  The bigger my program gets (max. about 1K),
  the less signal I get at CLKOUT. Does program
  size have anything at all to do with the
  oscillator circuitry ?

If anyone can give an answer to these
(ridiculous ?) questions I would be most
gratefull !

Thanx anyway.
Ben.

1997\05\21@124156 by John Griessen

flavicon
face
At 05:42 PM 5/21/97 +0200, you wrote:

>1) When I look at the OSCOUT pin of my 16C74
>   I see the following sine : 1 to 2 Vpp AC
>   and 2.5 V DC. Is this normal or should the
>   signal be larger. (Is the DC voltage OK ?)
>   What could be the problem ?
If you are running at 5V, there is no problem...2.5 is right where the DC
should be, between 5V and gnd. the sine wave is good, that means your
oscillator is working.  The size of it is likely affected by the
oscilloscope impedance loading it down.

>2) Very strange, the next one ...
>   The bigger my program gets (max. about 1K),
>   the less signal I get at CLKOUT. Does program
>   size have anything at all to do with the
>   oscillator circuitry ?

The size of it is likely affected by the oscilloscope impedance loading it
down.  it can be affected and act strange when loaded down by the scope,
changing the crystal frequency a little, and sometimes making it stop.
It's OK if that's what it is.  If you are worried that the oscillator is
steady, make a timer go off at a steady count of clocks and see if that
frequency drifts and is not steady.  otherwise    no hay problema!

Remember:   the Heisenberg uncertainty principle, Ilya Prigogene's
theories, and everyday life all suggest that life is strange.  No big deal.
JGriessen

>
>If anyone can give an answer to these
>(ridiculous ?) questions I would be most
>gratefull !
>
>Thanx anyway.
>Ben.
>
>

1997\05\22@083217 by Tom Handley

picon face
re: OSC Output

  Ben, I would'nt take those readings literally. I have'nt followed
the beginning of this dialog so I don't know why you are looking at
this. You need to consider the impedance and the capacitance of the
probe you are using. Are you using a crystal and/or are using OSCOUT
to drive another PIC?

  - Tom

At 05:42 PM 5/21/97 +0200, you wrote:
{Quote hidden}

More... (looser matching)
- Last day of these posts
- In 1997 , 1998 only
- Today
- New search...