The Arduino UNO uses the ATmega328P-PU microcontroller, which comes pre-loaded with the Arduino UNO bootloader. A bootloader is a small program that enables the microcontroller to be programmed via USB or serial, eliminating the need for an ICSP programmer.
If you're developing a project based on the Arduino UNO and designing a custom PCB, you'll need a bootloader-flashed ATmega328P. This DIP-packaged microcontroller includes the Arduino UNO (16MHz) bootloader, allowing you to upload Arduino sketches to your custom hardware without using an actual Arduino board.
To use it with the Arduino IDE, you'll need:
-
An external 16MHz crystal or resonator
-
A 5V power supply
-
A serial connection
Be sure to select "Arduino UNO" as the board in the Arduino IDE.