Hi!
I have to power my mega328 from 3,3V so I need to decrease oscillator freq. Is it ok if I just swap 16MHz oscillator with 4MHz oscillator? I would like to change "external for external" so should I change fusebits?
Thanks
Yes.
If you go with 8 MHz, can even use an existing board type, such as 3.3V 8 MHz Promini.
I'd like to put 4MHz osc, so after this I have to change value in arduino IDE config file?
Need to change it somewhere, not exactly sure where.
Maybe make a new board type in boards.txt with the 4MHz frequency.
Check the boards there, maybe one exists with 4 MHz already.