0 5 lfuse BOOTRST 1 Boot Reset Vector Enabled 1 4 lfuse SPIEN 0 Serial program downloading (SPI) enabled 2 3 lfuse SUT 1 Start-up time 3 2 lfuse CKSEL2 0 Select Clock Source 4 1 lfuse CKSEL1 1 Select Clock Source 5 0 lfuse CKSEL0 0 Select Clock Source