ATmega328-PU 8-bit Microcontroller by Atmel. Package: 28-pin (narrow) DIP = "- PU package" *** but simply marked ATmega328 U - so not the pico-power P-PU version *** Download ATMEL ATmega328-PU .pdf datasheet: Status: NOS (New Old Stock) Individually tested components: YES RoHS compliant : no