My Arduino got damaged by a short circuit so I tried my board with a simple code it gives me wrong results, so is there any way to reset or format it?

  • 3
    What simple code did you upload? Typically you first need to check what is damaged on the board. Sometimes it is just a simple component sometimes you have to throw the board away. Then if the AVR seems to behave incorrectly you can try to check if this is the whole chip or only some I/O pins.
    – jfpoilpret
    Sep 12 '14 at 18:58
  • @jfpoilpret the simple code is controlling some LEDs , they are powered correctly but not in the order i coded it Sep 12 '14 at 20:31
  • @jfpoilpret how can i check for the faulty part > Sep 12 '14 at 20:32
  • 1
    Would you mind edit your question and post the program you uploaded and describe how it behaves? That could help diqgnose the state of your board.
    – jfpoilpret
    Sep 12 '14 at 21:28
  • 1
    First ensure that upload works (it seems so) simply by checking the IDE does not report any error. Then upload a program that just uses Serial to exchange data with the serial monitor. Then upload a program to check one pin at a time. Do this for output then input. If all tthat works then your Arduino is probably in a quite good shape.
    – jfpoilpret
    Sep 12 '14 at 21:28

From: https://stackoverflow.com/a/6089103/9392580

Try the following:

  1. Prepare the basic empty program (empty setup, loop, etc.)
  2. Compile it.
  3. Reset the Arduino using the hardware button on the chip
  4. Press Ctrl + U to upload your code.
  5. If unsuccessful - got to 3.

There is a delay before the boot loader starts the programs, just work on your timing. It worked for me when a bug in my Arduino's code was executing a soft reset every 500 ms.


I had a similar problem with my Arduino Nano 33 IoT, where I uploaded a program that immediately put it into sleep mode (completely unintentionally). I could not get the COM port to show, and consequently could not upload a corrective program. After scouring the internet, I found two methods to put the mode where you should be able to upload a basic program (such as an empty sketch or the Blink example).

  1. Double-tap the reset button. This will put the Arduino into a mode where the bootloader is waiting for an upload. You will know it is in this mode as you will see the LED do a slow 1 second fade on and off.
  2. Hard Reset. Plug the Arduino into the USB port. Then place a jumper between the Ground and the Reset pins. Finally hit the reset button. You should see the LED perform the same on and off slow-fade.

Unfortunately, neither of these methods worked for me. After a few hours of fiddling with it, I was ready to call it a brick, and return it the Arduino company to see if they could rescue it. However, just before I gave up on it, I had a flash of insight. I swapped my USB cable...and the port showed up just fine on the computer.

I'll leave this here in case anyone else has a similar problem.

  • but the question was about Uno which uses a separate USB chip so the Arduino 33 IoT information will not help here.
    – Juraj
    Dec 10 '21 at 8:23
  • The reset process is the same for both, and no one actually answered the "How To Reset" question.
    – Los2000
    Dec 10 '21 at 17:51
  • no. the reset process is very different. for boards with USB chip, DTR signal is used to activate the reset pin of the MCU over the auto reset circuit. For boards with MCU with native USB, Arduino uses 1200 baud connection as reset signal processed by the USB code from Arduino core.
    – Juraj
    Dec 10 '21 at 20:03

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