We recommend viewing the lesson on registers before tackling the concepts shown in this video:    • Level Up Your Arduino Code: Registers  

We examine external interrupts on this episode of Adventures in Science as we continue our journey learning about the inner workings of Arduino. External interrupts are anything that’s outside (but connected to) the microcontroller and can interrupt the main execution thread to perform some action. We look at the attachInterrupt() Arduino function and then break it apart to set up an interrupt by manually writing to registers.