I’M GOING TO USE FREERTOS WITH AN ATMEGA8515 ON STK500,I KNOW THAT IT HAS LOW RAM AND I’M THINKING OF USING EXTERNAL RAM, COULD YOU GIVE INFO IF IT IS POSSIBLE THAT? IS THERE ANY SCEMATIC OF HOW I WILL ADD THE EXTERNAL RAM? BECAUSE OF THE HIGH COST OF STK501 HERE IN GREECE I’M TRYING TO USE ONLY THE SKT500 AND ANY OTHER IDEAS… THANKS. N. POL

Your best bet for AVR schematics would be AVRFreaks. Have you tried there?  THey are normally very helpful. http://www.AVRFreaks.net