All right, so using "ISR" and "non-ISR" and skip this "fore-/background" thing altogether is better then, right ? Never mind, it was just a thought :-) :-) Jan-Erik. >This still confuses me after more than 20 years in this field. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu