National Cemetery Administration (NCA) Facilities Design Guide

Keep ISRs short! Long (too many lines of code) and slow are the twins of ISR disaster. Remember that long and slow may be disjoint; a five line ISR with a loop can be as much of a problem as a loop-free 500 line routine. When an ISR grows too large or too slow, spawn another task and exit. Large ISRs are a sure sign of a need to include a RTOS. ................
................