AVR-Chat

On Wed, Apr 16, 2008 at 1:48 PM,  <kholt@sonic.net> wrote:
>  With this much frequency change, it appears that the crystal is dead
>  or unconnected, and the oscillator is running on capacitance only.
>

Something is squirrely, that's for sure.

Is the processor's VCC properly bypassed?


Crystal cap selection: (short version)

Look at the data sheet for the crystal you are using.
(If the crystal is something without a spec, then you are on your own)

Find the loading capacitance value.
Double it.
Subtract 5pF
Round to closest standard value.

This results in a value that's nearly twice the Cl value, but that IS
the correct way.
22pF caps on a 22pF crystal is WRONG.