I believe the diode is to prevent the voltage overshoot from the auto-reset circuit. Without, it has caused chips to go into high voltage mode and wiping out the memory. This has been added to all newer versions of Arduino boards.
I believe the diode is to prevent the voltage overshoot from the auto-reset circuit. Without, it has caused chips to go into high voltage mode and wiping out the memory. This has been added to all newer versions of Arduino boards.