oscillator use

Community PCB Design
1

I’m working on a board that will have an external osc. Previously I’ve just stuck with the internal 8 mhz oscillator found in many AVRs, but this time I figured I’d add an external one. A couple of things I want to double check with you guys:

FYI: I’m looking at this guy:

http://www.sparkfun.com/commerce/produc … ucts_id=94

Sparkfun sku: COM-00094 (in case the link doesn’t work).

1, The specified load capacitance, is that the same capacitance values that I want to use for the caps that short XTAL1 to GND and XTAL2 to gnd? in this case 12pF?

2, is this a “low power crystal osc.” or a “full swing crystal osc.”? It does matter in the fuse settings on the AVR (I’m looking at ATmega1280 - page 40 if anyone is interested).

Thanks!

Marcus

2

The capacitors are effectively in series, so you need something like 22 pF each; there will be some stray capacitance.

Leon