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Topic: Serial port 'COM3' already in use (Read 1 time) previous topic - next topic


Hi, all,

My mega1280 board ran into 'Serial port 'COM3'  already in use' error recently, it would be out of work even if I close the IDE and serial monitor, I checked the computer and found no applications were occupying the serial port. It might be OK after powering off and restarting the board again.

I am wondering what's wrong with it.




Sometimes Windows just loses it's mind. You can they unplugging the mega, deleting the serial port in Device Manager, then plug the mega back in so it reinstalls the driver.


Excuse my english.
Do you installed arduino with old arduino application driver and now you use other arduino application version?
If the answer is yes , try to put back old version or reinstall driver for your arduino from new version directory(drivers).
If doesn't work try to reburn with new bootloader.


im getting same problem all the time... nothing else running on ports, uploaded one sketch then nothing but the same problem ever since. Is it arduino uploaded software causing problem? have tried every suggestion...running windows xp and mega 2560.


Do you have any string containing "!!!"? That causes the Mega to glitch up, etc., and is a known problem. If that is the case, search around for solutions.

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