Serial port remains open after Serial Monitor is closed

[sayzergithub]

Describe the problem

Once the serial monitor is opened, and then closed later on, port stays open while IDE is running.

To reproduce

1. Connect a board to your computer.
2. Select the board and port from the Arduino IDE menus.
3. Open Serial Monitor.
4. Close Serial Monitor.
5. Attempt to open the port in an external serial port monitor.

🐛 The external serial port monitor can not access the port.

Expected behavior

The port is closed when Serial Monitor is closed.

Arduino IDE version

2.0.0-rc9.4

Operating system

Windows

Operating system version

10

Additional context

I am using an ESP32 board with Silicon Labs CP2102 USB-Serial port chip.

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I also experience the problem of the port being reset when the IDE is closed as reported at #1546, but it occurs even when I already closed Serial Monitor before closing the IDE.

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details

[per1234]

Hi @sayzergithub. Thanks for your report.

I did some experimentation but was not able to reproduce the issue.

port stays open while IDE is running

What are you doing to determine that the port stays open?

Connect a board.

Which specific board (or boards) have you encountered this issue with?

Board resets.

What are you doing to determine that the board reset?

[sayzergithub]

"What are you doing to determine that the port stays open?"
Using an external serial port monitor, it can not access the port.

"Which specific board (or boards) have you encountered this issue with?"
ESP32 with SILAB CP2102 USB-Serial port chip.

"What are you doing to determine that the board reset?"
Immediately after IDE is closed, ESP32 board restarts.

[per1234]

Thanks for the clarifications. In order to progress with the investigation, I'm going to ask you to try an experiment and then report your results here.

Please try this:

1. Open the Windows "Task Manager":
   https://techcommunity.microsoft.com/t5/windows-11/how-to-run-task-manager-on-windows-11-6-ways/m-p/2701239
2. If it is not already in that mode, click the "More details" button at the bottom of the Task Manager window.
3. Select the "Details" tab in the Task Manager window.
4. Start the Arduino IDE.
5. Select the board and port for your ESP32.
6. Open Serial Monitor.
7. Switch to the Task Manager window.
8. Verify that you can see a process with the name "serial-monitor.exe".
9. Switch to the Arduino IDE window.
10. Close Serial Monitor in the Arduino IDE window.
11. Switch to the Task Manager window.

After following these instructions, do you still see a process with the name "serial-monitor.exe" in the Windows "Task Manager"?

[per1234]

Hi @sayzergithub. Did you ever get around to trying the experiment I requested in my previous reply? If so, what was the result?

[sayzergithub]

Hello, I am having some health issues with my kidneys. I will try your suggestion as soon as I am up and running again.:) Thank you, Ömer YILDIZ MCU Embedded Systems Designer

[per1234]

Since we didn't receive any additional reports or the additional information needed to investigate, I'll close this issue. If anyone is experiencing this problem with the latest version of Arduino IDE, please comment here and we will continue with the investigation.

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Note there is a confirmed bug that causes the equivalent problem with Serial Plotter. That is tracked in the dedicated issue #1423