I've been trying to set the fuses in an ATmega 168-20PU so that it uses a 20MHz external crystal (with 18pF caps).
So far I've managed to tank one of my '168s :D. Will get that back with HVPP, but I wanted to run my fuse settings past you fellows:
I'll list all settings just in case:
SPIEN - checked
WDTON - not checked
EESAVE - not checked
BODLEVEL - disabled
CKDIV8 - not checked
CKOUT - not checked
SUT_CKSEL - EXTXOSC_8MHZ_XX_16KCK_14CK_65MS
EXTENDED - 0xF9
HIGH - 0xDF
LOW - 0xFF
I did try the http://www.engbedded.com/fusecalc/ but that gives a duff answer (well, more likely my not understanding it may have :p).
Any advice much welcome!