Arduino Uno Mega 16u2 Pinout Nico edited this page on Jan 29, 2019 · 4 revisions (c) pighixxx Note: Some pins are not connected on a standard Arduino Uno R3 but still listed so you can use them if you ...

Note: Some pins are not connected on a standard Arduino Uno R3 but still listed so you can use them if you had a custom board. It might also be possible that your ICSP header of the 16u2 is flipped ...

It's of course backwards compatible with existing Arduino add-ons, but sets itself apart with a new USB controller with lower latency and driver-free operation on Mac and Linux.