https://github.com/MicrochipTech/avr_insights Learn about External Interrupts on AVR devices. The external interrupts on AVR devices can trigger on rising and falling edges and low level drops, all on the same pin. External interrupts use these triggers for saving power during device operation. External interrupts are useful for projects and applications that enter sleep mode and leave sleep mode based upon an external trigger, such as a button press. The external interrupt wakes the device from various sleep modes, without the CPU constantly needing to check the device. Check out the example below to see how! Documentation references -------------------------------------------------------------- Atmel Tools Documentation: https://mchp.us/2YkFqNk AVR Libc reference manual: http://www.microchip.com/webdoc/AVRLibcReferenceManual/group__avr__interrupts.html ATmega324PB datasheet - External Interrupts: http://ww1.microchip.com/downloads/en/DeviceDoc/40001908A.pdf#page=78 ATmega324PB Xplained Pro User Guide: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-42633-ATmega324PB-Xplained-Pro_User-Guide.pdf App note AVR1200: Using External Interrupts for megaAVR devices: http://www.microchip.com//wwwAppNotes/AppNotes.aspx?appnote=en590935 AVR, MCU, ATmega324PB, mega324, mega, mega324PB, example, explained, xplained, xplain, insights, insight, tinyAVR, megaAVR ,tiny, mega ,Microchip, Atmel, Interrupt, interrupts ,vector table , AVR1200, external trigger,pin change, level change ,edge ,sleep mode ,idle ,Wake up, wake on button press, wake microcontroller, microcontroller sleep mode wake up