Just my notes...
avrstudio 4.07 has the following bugs:
- data segment is not initialized (maybe objtool issue?)
- ETIFR |= _BV(ICF3) does not clear (special bit according to the datasheet) the flag, but set it
- 4MHz by default, not a big deal... (divide elapsed time by 4, counters also use this clockbase. I remember I once could set it to 16MHz, now cannot)