External oscillator

Projects General Guidance
1

Hi

Which Arduino boards use an external crystal oscillators for their system clock.

Thanks you.

2

Arduinos use less precise Resonators.

How external? Removable? Do you own a soldering iron and some desolder wick?

3

Looks like the following boards all have crystal oscillators:

Leonardo, Mega 2560, Mega ADK, Mini, Micro, Ethernet, Esplora, BT.

I assume that they are external oscillators since to my knowledge the internal oscillators of all microcontrollers are all the RC oscillators. I'm I correct?

4

The original Uno (R1, but not marked as such) had a resonator but also space for a crystal and caps.

5

D_J_S:
Looks like the following boards all have crystal oscillators:

Leonardo, Mega 2560, Mega ADK, Mini, Micro, Ethernet, Esplora, BT.

I assume that they are external oscillators since to my knowledge the internal oscillators of all microcontrollers are all the RC oscillators. I'm I correct?

Nope, when you use a crystal the "oscillator" is some circuitry inside the chip. The RC oscillator is also inside but so is the xtal oscillator.

As for the OP, I don't think any Arduinos use an "external crystal oscillator" as technically that's a chip in it's own right, but most (all?) use either an external crystal or a resonator.

Rob