user67218: How do you use Atmega328p-PU from an Uno, on a breadboard without a crystal?

user67323: You can use another IC like the 555 timers as an external oscillator.

67218: <p>How do you use Atmega328p-PU from an Uno, on a breadboard without a crystal?</p>
 67323: <p>You can use another IC like the 555 timers as an external oscillator.</p>
