Upload Issue after Resonator Change

Hello,

I have a project that utilizes the Atmega328P-PU chip (purchased with Arduino bootloader on it) and haven’t had any issues when i was using the external 16MHz resonator.

Recently I changed this to a 2MHz external resonator to reduce current draw. I went in and changed the fuse settings per the attached picture but wasn’t getting it to upload… I was getting sync errors during the upload.

Reading around on the forum it sounded like my upload speed may have gotten messed up since i changed the clock frequency… Taking a wild guess it from 57600 to 7200 (i.e. 16mhz/2Mhz = 8). It looks like it uploads fine but i did get a “non standard baud rate” message, but it all seems to work fine… Anything to worry about? I attached the upload message data as well.

upload_message.txt (53.2 KB)

You changed the resonator but not the bootloader. Upload speed is hard coded in bottloader so it expects always 57600. However, also expecting clock speed is 16MHz. It is 7200baud in result.
16/2 = 8 = 57600/7200