First sorry for my english.
My sketch stopped to start on DUE. Everything was ok, but once after adding few lines of "Serial.print()" code for debug purposes, uploaded sketch not started. Tried reset, erase buttons, uploaded again and nothing. Other simple sketches from examples starts with no problems. Added first lines in setup function:
Led still on!
My sketch is not very simple - "Sketch uses 130 620 bytes (24%) of program storage space. Maximum is 524 288 bytes."
I have removed some code with a lot usage of memory, sketch space usage decreased from 32% to 24% - still nothing.
Thank You for help!