I'm just curious about this because a lot of my PIC chips say in the datasheet that they hold their programming for 40 years. Don't get me wrong, thats long enough, I'm sure anything I make will be forgoten or broken in another way by 2050 anyhow. But I can't find anything that goes into more detail about this and im curious. Do they really loose their programming? What is the main cause of it? Are their chips that boast extended program retention?