I use an Arduino Mega for testing and that works fine. I use Adafruit 5V Pro Trinkets for the actual evices I make and that has worked fine...up to now. Suddenly, the serial port for a connected Pro Trinket is greyed out...on ALL my Pro Trinkets and I have about 20 of them. They worked yesterday. …

Serial Port greyed out.

ieee488 April 8, 2018, 3:27pm 3

Can you try a different USB port?

Wondering if you blew up the one you were using.