LED Blinking Hardware
The LED circuit is effectively four LEDs that are independently controlled using four different GPIO pins of the ATMEGA328P.
These LEDs are cycled on and off using a simple blink program providing a trivial aesthetic effect, but its primary purpose is the functional verification of the ATMEGA328P. The visual indicator allows the user to determine if the microcontroller is bootloaded, which means it is capable of receiving code uploads. This check is particularly important as discrete ATMEGA328P chips are typically sold without a pre-installed bootloader.