Hi all:
I bought my first arduino. I keep getting the same error message when trying to upload code. I followed all the instructions on the page for the installation. I'm using the IDE 2.0. When I plug in my arduino it says it's registered on COM3. The green light is on and the L , LED is flashing (I've read this is pre installed from the bootloader). But when I try and upload the blink LED program it reads...
avrdude: ser_open(): can't open device "\.\COM3": The semaphore timeout period has expired.
On my computers device manager it says the arduino is connected to COM3. I'm not sure what the issue is. Any advice would be greatly appreicated. Thanks!
Its an arduino uno by the way. I've changed which port on the computer I plug the USB cable into but it always says the arduino is with COM3
Is any external hardware attached to the board?
It's an error that often shows its ugly head. A quick search (arduino The semaphore timeout period has expired - Google Search) reveals e.g. https://forum.arduino.cc/t/avrdude-ser_open-cant-open-device-com5-the-semaphore-timeout-period/396834/4which might solve your problem.
Open the Device Manager on the PC, Expand the Ports (COM and LPT), plug in the UNO and see what COM port the PC thinks you are using.
You can also get a similar errorif you have something else using the com port. Like a terminal program for example.
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