Article created: "Can't set com-state for..." [HC-1293] (#340)

* Article created: "Can't set com-state for..."

* Remove id from front matter (new article)

* Remove duplicated step

* Reworked the article structure

Based on further testing.

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Co-authored-by: seaxwi <71350948+seaxwi@users.noreply.github.com>

Author: gorillagripcore

content/Software Support/Upload/avrdude-ser-open-cant-set-com-state-for-COMn.md

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+---
+title: "avrdude: ser_open(): can't set com-state for COMn"
+---
+
+An "`avrdude: ser_open(): can't set com-state for COMn`" error can occur when uploading to the boards that use specific batches of the [WCH CH340 USB chip](http://www.wch-ic.com/products/CH340.html). The problem only occurs when using the latest version of the CH340 driver, and can be solved by installing a previous release.
+
+---
+
+## Download and install version 3.7.2022.01 of the driver
+
+Follow these steps:
+
+1. Download [version 3.7.2022.01 of the driver](https://www.wch-ic.com/downloads/file/65.html?time=2023-03-16%2022:57:59){.link-download}.
+
+1. Run the downloaded `CH341SER.EXE` file.
+
+1. A **User Account Control** dialog may now appear. Click the `Yes` button.
+
+1. A **DriverSetup(X64)** dialog will appear. Click the `Install` button.
+
+1. Restart Arduino IDE and try to upload the sketch again.
+
+To prevent Windows from automatically updating back to an incompatible version of the driver, use the [Roll back driver feature in Device Manager](#rollback).
+
+## Roll back the driver to stop automatic updates {#rollback}
+
+Follow these steps:
+
+1. Close the **DriverSetup(X64)** dialog and **Arduino IDE** if they are running.
+
+1. Connect the Arduino board to your computer with a USB cable.
+
+1. Open **Device Manager** from the Windows Start Menu.
+
+1. Check your View settings:
+
+    * View > Devices By Type should be selected.
+
+    * Show Hidden Devices should be **not** be selected.
+
+    ![Screenshot of Device Manager with view menu and devices by type selected](img/View-Devices-By-Type.png)
+
+1. Open the `Ports (COM & LPT)` section. You should see a port identified as `USB-SERIAL CH340 (COM_n_)`
+
+    ![Screenshot of Device Manager, Ports (COM & LPT) opened and USB-SERIAL CH340 selected](img/Ports.png)
+
+    Right-click on it and select **Properties**.
+
+1. Select the `Driver` tab and confirm that 3.7.2022.1 is the installed driver version.
+
+   ![Device properties, Driver tab.](img/3.7-confirm.png)
+
+1. To enable rolling back to version 3.7.2022.1, we need to switch to a different driver. Select **Update Driver > Search automatically for drivers**. You should now see the driver installation wizard update the driver to a more recent version.
+
+   > [!WARNING]
+   > It is possible you will instead see the message "The best drivers are already installed". If so, follow these steps:
+   >
+   > 1. Close the Driver update dialog.
+   > 1. Download and install [version 3.8.2023.2 of the driver](https://www.wch.cn/downloads/file/65.html?time=2023-03-17%2016:47:34){.link-download}
+   > 1. Go back to device properties and select **Update Driver > Browse my computer for drivers > Let me pick from a list of available drivers on my computer** and install version 3.7.2022.1 again.
+   > 1. Finally, try **Update Driver > Search automatically for drivers** again.
+
+1. Confirm that the installed version is now 3.8.2023.2 (or later) and click the `Roll Back Driver` button.
+
+   ![Clicking the Roll back button.](img/roll-back-driver.png)
+
+1. Now that the **Driver Package rollback** dialog is open, click the radio button next to **My apps don't work with this driver** and press the `Yes` button to roll back the driver.