Not exactly schematics, but [Duckman] has some Arduino pinout diagrams he made using ASCII-art. These could be useful when pasted into source code as comments, documenting the pinouts for your ...

Next is the complete schematic diagram of a little Arduino board for your everyday projects. Use the Atmega328P chip, with Arduino bootloader loaded by you, as the brain of this economical circuit.

Sometimes, you'll also encounter Arduino tutorials in the wild that include links to a Wokwi circuit as creators and developers typically create one to show the project's schematic diagram. Other ...