1. try changing XT to HS .
2. try adding series resistor on OSC2  pin or 10k pot and slowly
    turn it ?
3. make sure your master clear pin do not have higher then 0.01 mf cap
    and your 5v is clean.

Andre Abelian

> Hi Donovan,
>
> I've found that 16 MHz or higher ECS oscillators with internal caps do NOT
> work with ANY PICmicros.  The built in 30 pF capacitance is too high.
>
> Take a look at Panasonic's resonators (with 20 pF built in capacitors or
> less) or use the ECS oscillators which do not have built in caps and add
> your own external 15-22 pF caps.
>
> Good luck,
>
> myke
> ----- Original Message -----
> From: "Donovan Parks" <dparks@UVIC.CA>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Thursday, June 21, 2001 12:36 AM
> Subject: [PIC]: PIC16F877 not working with 20.0 MHz Resonator
>
>
> > Hello,
> >
> > I am using a PIC16F877 - 20/P and wish to use a 20.0 MHz resonator with
> it.
> > I am using a ECS Inc. ZTT-20.00MX resonator.  It has build in capacitors
> and
> > thus I am connected it directly to the PIC, but the PIC doesn't work.  I
> > have a 4.0 MHz resonator (says ZTT on it) and the PIC works with it.
Any
> > suggestions?  Is there anything that needs to be changed when swapping
> > resonators?  I am testing with a simple piece of code that blinks an LED
> at
> > 1s (though this would be much faster at 20MHz).
> >
> > Thanks,
> > Donovan Parks
> >
> > --
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> >
> >
>
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