The Arduino Nano and Uno are equipped with very similar processors (the chip that essentially serves as the brain of the board). The Nano features an ATmega328, while the Uno sports an ATmega328P.

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 ...

While the pinout is very similar to the Arduino Nano’s, there are four (12-bit) analogue inputs rather than eight (10-bit). Some digital GPIO pins are numbered differently too.

It's like a shrunken version of the Arduino Leonardo as it features the same ATmega32U4 microcontroller, micro-USB port, and pinouts. It also operates at 5V and requires an external supply of 7 to ...