Trouble with connecting to the ttyUSB0 port on upload

[dbyy]

Hello,
I’m having trouble connecting to the USB port (ttyUSB0) after compiling.

I’m not sure whether that is a specific problem related to pio or a more general problem.

After a few cycles of compiling/uploading a sketch suddenly its posting the message

A fatal error occurred: Could not open /dev/ttyUSB0, the port is busy or doesn't exist

The command ls -lha /dev/ttyUSB* shows crw-rw-rw- 1 root dialout 188, 0 Mar 22 12:14 /dev/ttyUSB0 .

I also run dmesg grep | ttyUBS* which shows [751240.961172] usb 3-2.1.1: ch341-uart converter now attached to ttyUSB0 as last line.

It seems I can’t fix the problem except I’m closing pio and open it again. Which then makes the USB port available. I don’ think that can be the only measure to deal with the problem.

Is there anything else I can do to avoid the problem?

I know a similar problem was discussed here :

No access to USB-Port while using PlatformIO with Atom on Linux

Hey there, I just ran into a problem while trying to use PlatformIO to program a WeMos D1 R2 Board for an Exam of my University: PlatformIO does not automatically recognize my USB Port while trying to upload code to the board. And after manually configuring it on my Linux Mint (PlatformIO.ini -> upload_port = /dev/ttyUSB0 ) i get the error : cannot access /dev/ttyUSB0. I already added my user account to the dialout group to get root access on the usb port,but i still get the same Error, no mat…

but it seems to be of a different nature than my problem.

Any help is much appreciated.

TIA

[dbyy]

For all who might run into the same problem.

My mistake was that the serial monitor was still active from the previous compiling/upload cycle and therefor the new compile/upload couldn’t work since the serial monitor (USB0) was still busy.

Probably no surprise to the experts; but I thought pio would be so smart that it would stop the monitor when executing the (new) compile command. But it didn’t.

Now I’m a little bit smarter (again).

TY