Use RTC instead of TIMERF1 on small xmega processors.
Use RTC instead of TIMERF1 on small xmega processors.

jaehong/Xmegaduino,jaehong/Xmegaduino,jaehong/Xmegaduino,jaehong/Xmegaduino,jaehong/Xmegaduino,jaehong/Xmegaduino,jaehong/Xmegaduino