I'm going to have a go at making my own pro mini as I have a few projects that need shrinking down a bit (slightly smaller than a pro mini). I've done some research and have ordered all the necessary components, or so I hope. And i've got a lingering question that I can't quite find an answer to that I'm hoping someone here might be able to help with.
I've purchased a handful of ATMEGA328P-AU-ND chips (from Digikey) and the descriptions say they are running at 20 Mhz. Now when it comes to loading the Arduino bootloader / sketches do I need to manually do anything to the fuses? I'm going to be making two boards, the first at 5v - 16Mhz and and the second at 3.3v - 8Mhz, can I just assume that it will be as simple as using 2 different chrysalis then load a sketch? or do I need to dive a little deeper?
I admit that I don't quite understand what the fuses do but have often seen them mentioned when it comes to the running speed.
Apologies in advance if I've asked a silly question and there is already an answer out there somewhere. But I will appreciate any advice you have to offer