I may be publishing a TV remote control project that will be powered by two alkaline AAs in series. The controller will be the 3.3V 8MHz Pro Mini with power LED and regulator removed. The default Extended fuse setting is 0xFD, which sets the BOD voltage at 2.8V. Since the 328P will operate reliably down to 2.4V at 8MHz, and probably well below that, I want to change the fuse setting to 0xFE, which sets the BOD to 1.8V. I'm hoping that significantly extends battery life.
In my IDE v1.8, this can be accomplished by changing the fuse value on the appropriate line in the boards.txt entry for the 8MHz Pro Mini, and then burning the bootloader. I use another Arduino as the ISP.
I haven't installed any IDE v2, but downloaded the latest ZIP file and extracted it. I don't see a boards.txt file. So I'm wondering how I would change a fuse setting in IDE v2. Has anyone tried doing that?
In trying to research this, I ran across something called AVRDudess which might let me change the fuse outside the IDE. Has anyone tried doing that? Can you just change the fuse without having to reburn the bootloader. If you can, that might be the preferred solution regardless of IDE version.
Thanks for any guidance on all this.
At the first run of IDE 2.x, it will install some additional stuff. One thing will be the AVR board package (currently version 1.8.6, not likely to change in near future); it will be installed in a specific sub directory of (in Windows) C:\Users\yourUsername\AppData\Local\Arduino15. You will find the boards.txt in there.
Exact location: C:\Users\yourUsername\AppData\Local\Arduino15\packages\arduino\hardware\avr
Not familiar with AVRDudess but it's nothing more than a GUI for avrdude which comes with the IDE. So you don't need it specifically and you should be able to simply set the fuses using avrdude.
Please note that if you currently use a non-portable install of IDE 1.8 it will also start using the avr board package in the mentioned arduino15 directory if you use IDE 2.x on the same system.
Thanks very much.
I'm using portable v1.8.8. I was waiting until a portable version of v2 is available, but I guess I only need one of them to be portable for them to coexist.
Anyway, I've tried AVRdudess, and it is definitely the way to go. It has a portable version, and brings the latest version of AVRdude with it. You select the COM port, the programmer and the board, and there are buttons to read and write just the fuses without messing with the bootloader. You still have to flash the code to the programmer Arduino, then set up the connections and the capacitor on its reset, but then you're in like Flynn. And this is all done outside the IDE, so it doesn't matter which version you have installed.