0 5 fuse SPIEN 0 Enable Serial programming and Data Downloading (ignored) 1 7 fuse BODLEVEL 1 Brown out detector trigger level 2 6 fuse BODEN 1 Brown out detector enable 3 2 fuse CKSEL2 0 Select Clock Source 4 1 fuse CKSEL1 1 Select Clock Source 5 0 fuse CKSEL0 0 Select Clock Source