i know this is a dumb question to ask but::
I'm Using ATMEGA8PU And Arduino IDE1.6.5 There's No ATMEGA8PU On The Boards List What To Do .. And Where To Find The Core For ATMEGA8PU ??
In the IDE, under TOOLS>BOARDS if you select the option for "Arduino NG or older"
Then a select under TOOLS>PROCESSOR "atmega168" or "atmega8"
the processor option only comes if the boards selection gives you possible variants
