Quote Originally Posted by midali View Post
I want to blink very quikly a led in background ,independent of my code...I want learn about intrerupts but i think that I'm too old...
Try this as an intro to Darrel Interrupts and blinking LED:
http://darreltaylor.com/DT_INTS-14/blinky.html

It's worth the time to practice. His routines make things so much easier and flexible later on as you add more complexity to your code.

Robert