Hi, I´m doing a university project with arduino. The device controls the speed and the position of a motor with the PWM pins. My problem is that most of my digital pins have a constant voltage, when its should be a 0v, because I don´t use these pins in my program.

And I have notice that my arduino (only the chip ATMega 328) is too hot, so I though that I had fried my arduino, but I can load some programs like the blink led, and it works, but I still have mos t of my digital pin with a constant voltage. Can somebody help me?

Many things. If your unused pins are configures as inputs they should be floating and give you unreliable readings. What you observed might not be relevant.

As to having fried your ATmega328, you might have fried just parts of it while the rest still works fine. You need to check for each individual pin whether it still works properly (eg with a led and a resistor).


Thanks for your answer Korman.

I completly agree with you, is possible that I have fried only some parts of my Arduino, because I have just check the digital pins I´ve notice that some of these pins still works.

Nevertheless, I haven´t configure these pins as nothing in the setup part, so if I configure these pins as OUTPUTS, should these pins floats?

If you haven't configured the pins, they're inputs without internal pull-up enabled. You need to set pinMode to make them outputs.


If you have or think you have fried your ATMega, I would consider it suspect until ruled otherwise. Dab a bit of paint on it, put it in a drawer for later, and get new one to continue your work with. Otherwise you are left in a situation where any problem might be suspect, without a known state of the processor being good. Why beat yourself up over a $5.00 USD chip?

Of course crosh, obiously I will buy another one to continue my work, but as you Know, the time is gold, and buy another chip will waste at least one week, that´s why I have asked in this forum. However, thanks for your answer, and if you have any new idea don´t doubt in share it with us.

Korman, I have configure my unsed pins, as OUTPUTS and they still have a costant voltage of about 3.5 v. So I think, definetly, that I have fried part of my arduino´s micro.

All that's left to say is: and: