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Re: [avr-chat] at90can128 async crystal

From: Daniel Kruszyna
Subject: Re: [avr-chat] at90can128 async crystal
Date: Mon, 19 Sep 2005 13:07:15 -0400
User-agent: Mutt/

Joerg Wunsch <address@hidden> wrote:
> I think that's more a question of your crystal rather than the
> processor.  Quite often, the capacitance of the inputs and circuitry
> suffices as crystal load, but if your crystal specifies more than some
> 10 ... 20 pF, you probably need to add external Cs.

It's a citizen cm519, specified at 12.5pF. I'm not concerned with a
high precision clock, but it seems to be running fast by a factor of 6.
I can't think of a way to misconfigure timer2 and be off by this amount.
I'll add pads for the capacitors on the next board iteration for testing.
The newer avrs seem to require them regardless of crystal type.

-- Daniel

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