AVR-Chat

At 09:56 PM 11/20/2003 +0000, nangkon wrote:

>Thanks for your reply.
>
>I am planing to use a 16Mhz crystal with an
>atmega128 mcu. I saw some schematic use
>some values, and some do not use cap at all.

Ceramic resonators can come with the caps built in, but they have three leads. 
A crystal without caps, is just plain wrong.

>I saw some crystal spec mentioning about
>load cap. Does this value come into the
>formulate somehow? What if I do not use 
>cap? What will happen?

Good luck. A crystal with no cap spec is designed to run in series mode.
They MAY run in a parallel circuit, but you will never get them running at the right speed. 

The series and parallel resonant points can never be at the same frequency.

>I am pretty new to electronics. So when you mention about parallel operation. What
>do you mean? Outputing data to a port for example?

Nothing like that. 

I used to have some links that would explain this, but I can't find them at the moment, and I don't have time right now, perhaps someone else can step in?