I am trying to build a project with 2 Arduinos that communicate by rs485 ink. In the process of debugging I am often updating the code to add debug messages. I only get a successful load about 1 in 10 or 12 tries. I know I have the correct ports and device selection because it sometimes works.
I have tried 2 different Pcs, and several Uno boards, both genuine and clones.
I always have to unplug all my shields, even though I am sure pins 0 and 1 are not connected in my project.
I have seen lots of posts about total failures, but nothing on this random problem. Anyone have suggestions? Should I get some kind of AVR programmer and give up on USB loading?