Which Datasheet applies to the ATmega328p?
You have ATmega328P-AU. Classic Uno with DIP socket has ATmega328P-PU. Arduino Uno SMD has Atmega328P-MU.

The automotive versions ATmega328P-15AZ and ATmega328P-15MZ have separate datasheet starting in Revision History with


  Creation of the automotive version starting from industrial version
  based on the ATmega48P/88P/168P/328P datasheet 8025F-AVR-08/08.
  Temperature and voltage ranges reflecting automotive requirements.