In IDE 1.8.8, I noticed that under Tools>Programmer>AVRISP mkll would be checked when the program started up. I assumed this is the protocol that is used when sketches are uploaded to a board such as Arduino UNO. In IDE 2.3.4 under Tools>Programmer, none of those options are checked. However, uploads of sketches work fine without anything being checked under this menu. Can someone explain why the differences and what protocol is actually used when sketches are uploaded to a UNO board? Thanks for the help!
Hi @stuzman. When uploading to the Arduino UNO board, the Tools > Programmer menu selection has absolutely no effect. The Programmer menu selection is only used for this board when you perform an "Upload Using Programmer" or "Burn Bootloader" operation.
The the Arduino UNO board's platform is not configured to provided support for use with the Arduino IDE 2.x integrated sketch debugger, but for boards that are compatible with the debugger, the Tools > Programmer menu is also used to configure which debug probe you are using as the interface between the computer and the board.
With certain 3rd party boards platforms supporting boards that can only be uploaded to using a programmer, for the convenience of the user the platform developer has configured the board definition so that clicking the "Upload" button actually causes Arduino IDE to perform an "Upload Using Programmer" operation.
The arduino protocol is used: