If you have a probe on the oscillator input the probe capacitance will load
the input and skew the frequency. Similarly it's usually a waste of time
looking at the input pin of an op-amp with a scope, because the op-amp is
trying to make it a virtual ground (if it's wired as an amplifier).
/\/\/\/*=Martin

----- Original Message -----
From: "Dans_PIC_Stuff" <dans_pic_stuff@HOTMAIL.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Friday, February 01, 2002 3:18 PM
Subject: Re: [Pic]: Measuring resonator frequency


> I'll try that next class.  I also tried using 2 hhannels, one on each
> resonator pin of the PIC.
>    -Dan
> ----- Original Message -----
> From: "Andrew Warren" <aiw@CYPRESS.COM>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Friday, February 01, 2002 10:47 AM
> Subject: Re: [Pic]: Measuring resonator frequency
>
>
> > Dans_PIC_Stuff <PICLIST@mitvma.mit.edu> wrote:
> >
> > > How can I connect a scope to a resonator to measure it's actual
> > > frequency? I took a 16F84 with a 4MHz resonator to my Electronics AC
> > > circuits class and tried testing it on one of their scopes but it
> > > didn't look too prety and it made the PIC's program slow down
> > > dramatically.  Any tips?
> >
> > Dan:
> >
> > Put the scope probe on the Xtal OUT pin, not Xtal IN.
> >
> > -Andy
> >
> > === Andrew Warren -- aiw@cypress.com
> > === Principal Design Engineer
> > === Cypress Semiconductor Corporation
> > ===
> > === Opinions expressed above do not
> > === necessarily represent those of
> > === Cypress Semiconductor Corporation
> >
> > --
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> >
> >
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