I have an arudino mega, I was working with it for a long time without any problem. I am controlling stepper motors with drivers runing on 12V. So yesterday I uploaded a program and tested it multiple times. It worked.
But today, as I plugged in the arduino I expected it to execute the program I left on it. But it didn't do anyting, so I wanted to upload the program again, but I can't see the port in the menu.
When I plug the arduino in the ON led blinks once, and also the L led but with a weaker light.
As I wrote these things down, I tried to connect an arduino nano's gnd and 5V pins to the mega's, to check if my cable is bad.
With this, both leds were constantly on. Then I connected the mega through the usb cable to the computer (while connected with the nano's 5V and gnd) and imagine, the program started to work! :DD
I am not sure what I did is healthly, but since I already wrote down my problem I thougth I still ask If someone knows what the porblem was. Also if someone has the same problem this seems to be a possible solution, I can see the port now in IDE and it seems to work just fine.
I am using all 6 hardware inteerrupts and changing the timers' compare match registers' values in my code. Maybe this caused the problem?