Q. What is the difference (apart from price) between the Atmega 328-PU and the Atmega 328P-PU?
A. Hi Keith. Thank you for your question. The main difference between the "P" version and the non "P" version is that the "P" version has lower power consumption.
Fix your broken Arduino
Reviewed by: Tom Lynch - 09 February 2014
This microcontroller is the same part installed in many Arduino boards, including the Arduino Uno, and Duemilanove. This means it is a fantastic drop in replacement for broken Arduino boards when a pin has died from overcurrent conditions for example. The chip is also a great basis for building your own Arduino on a breadboard when coupled with a USB AVR programmer like (73-4266) or the open source Adafruit USBtinyISP.