The name says it all on this one. An ATMega328 in DIP package, pre-loaded with the Arduino UNO (16MHz) Bootloader. This will allow you to use Arduino code in your custom embedded project without having to use an actual Arduino board.
To get this chip working with Arduino IDE you will need an external 16MHz crystal or resonator, a 5V supply and a serial connection. If you are not comfortable doing this, we recommend purchasing an Arduino development board that has all of these built in.
Atmel’s ATMega328 8-Bit Processor is in a 28 pin DIP package. It has 32K of program space, 23 I/O lines, 6 of which are channels for the 10-bit ADC. It runs up to 20MHz with external crystal. The package can be programmed in circuit. It uses a supply voltage of between 1.8V to 5V .