The ATmega328p is one of the most commonly used microcontrollers in DIY Electronics. The main reason is that this IC powers the most recent versions of the Arduino Uno—the most popular Arduino development board to date.
Available in both DIP (as in this listing) and SMT packages, the ATmega328p offers 32K of program space, 23 I/O lines including 6 lines with 10-bit Analog to Digital Conversion. It can operate at up to 20MHz with an external crystal, and use 1.8V to 5V as its operating voltage.
The pre-programmed ATmega328p microcontroller allows you to make an Arduino on a breadboard, or to incorporate it into any project requiring a microcontroller. This IC will also work as a drop-in replacement for a damaged chip on either an Arduino Uno, Duemilanove, Diecimila, or NG (with the Optiboot option)!
No matter what bootloader option you select, you'll be able to load a program onto the ATmega328p using the Arduino IDE. However, each option has its own specific (dis)advantages, so please have a look at our corresponding Application Note and Tutorials.
This option is for the original bootloader used in the Arduino Uno develoepment board, it allows users to upload their programs using a USB-to-Serial UART adapter.