Searching \ for 'PICBASIC-L 16F877 xt oscilator problem' 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/microchip/languages.htm?key=basic
Search entire site for: 'PICBASIC-L 16F877 xt oscilator problem'.

Truncated match.
PICList Thread
'PICBASIC-L 16F877 xt oscilator problem'
1999\11\13@024513 by Leo

picon face
Hi PICer friend,

I need to thanks all of you, for your precious support. Your suggestion have
put me on the correct way to start the PIC.

I have removed the two capacitors and connected only the 4 Mhz quartz to the
13 and 14 pins. Now the circuit run and the 16F877 works :-)

Thanks again friends for your precious help!

But the problem is not completely solved. Looking with a scope at the quartz
lead, on pin 13 stay a level of 2 Volt with a noisy of 0.2 Volt  and on pin
14 stay a sinusoidal wave between 0 Volt and 2.5 Volt. It is correct ??

With a scope lead connected on pin 13, if I touch by hand and the case of
the quartz the level of noisy increase between 1.5 and 2.5 Volt.

Sometimes try to touch and retouch the xtal case, the level on pin 13 seems
that switch in one condition and the noisy go between  -0.5 Volt and 2.2
Volt. When I release the case the noisy go between -0.5 Volt and 0.5 Volt
and after about one second the level return to the original level of 2 Volt.

But the stange is this:

I have loaded a simple program that switch the on/off all output pins and
touching the xtal case the square wave on that pin remain stable.

This phantom symptom on xtal is dued to the scope lead or is real??

Ciao

Leo

1999\11\13@035559 by Jinx

face picon face
Leo, earth the xtal case to the ground on your circuit by carefully
soldering
(don't use too much heat) a wire between the metal case and circuit
ground. Sometimes I found that a xtal needed a 4M7 resistor across it.

Jinx

> With a scope lead connected on pin 13, if I touch by hand and the case of
> the quartz the level of noisy increase between 1.5 and 2.5 Volt.
>
> Sometimes try to touch and retouch the xtal case, the level on pin 13
seems
> that switch in one condition and the noisy go between  -0.5 Volt and 2.2
> Volt. When I release the case the noisy go between -0.5 Volt and 0.5 Volt
> and after about one second the level return to the original level of 2
Volt.

More... (looser matching)
- Last day of these posts
- In 1999 , 2000 only
- Today
- New search...