CKOPT (was Re: [avr-chat] avrdude-ATMega32 fuse bits issues)

[Graham Davies]

Richard Urwin wrote:

> I found the datasheets ambiguous when I built for the
> ATMega16. It says CKOPT should be programmed
> for fast resonators, but it does not mention crystals.

Underneath the paragraph about resonators there is a table, Table 4. in my
copy of the data sheet.  This table tells you how to set CKSEL3..1 for
various frequency ranges.  It also gives a binary value for CKOPT.  From
this and knowing that 1 is unprogrammed and 0 1s programmed you can figure
out that CKOPT should be programmed for frequencies above 8MHz, just as
Brian says.  I would have presented it differently, but the information is
there.

Graham.