Hi @najsik. Please tell us which USB to serial adapter chip your Arduino board has. This is a black chip near the USB socket.
The chip will usually be identified by writing on the top. This might say something like "Atmel MEGA16U2" or "WCH CH340G" or "SILABS CP2102" or "FTDI FT232RL".
If it isn't clear, alternatively you can provide the link to where you bought the board from and we'll see if we can determine the chip from the product listing.
How do you know that your Arduino is connected to COM5?
Check the IDE Ports menu where your Arduino is currently listed. If no port shows up then follow the hints given by others already.
OK, great. Even though the chip isn't marked, as v205 mentioned, we can tell from the IC package this is the WCH CH340. There were some previous reports of this error occurring specifically when using boards that have the CH340 USB chip. It seems that a driver upgrade included in a recent Windows update is the cause of this problem.
The affected users have found that uninstalling reinstalling the CH340 device fixed the problem. I'll share the instructions you can follow to do that:
Close Arduino IDE if it is running.
Connect the Arduino board to your computer with a USB cable.
Select View > Devices by type from the Device Manager menus.
Open the "View" menu.
If there is a ✓ to the left of the "Show hidden devices" menu item, click on "Show hidden devices" to disable it.
Open the "Ports (COM & LPT)" section of the Device Manager tree.
You should see a port identified as "USB-SERIAL CH340 (COM_n_)" under the "Ports (COM & LPT)" section (where "COM_n_" is some serial port e.g., COM4). Right click on that item.
A context menu will open.
Select "Uninstall device" from the context menu.
An "Uninstall Device" dialog will open.
Check the box next to "☐ Attempt to remove the driver for this device" in the "Uninstall Device" dialog.
Click the "Uninstall" button.
Wait for the uninstallation process to finish.
Unplug the USB cable of the Arduino board from your computer.
Wait for the Device Manager tree to reload.
Connect the USB cable of the Arduino board to your computer.
Wait for the "USB-SERIAL CH340 (COM_n_)" port to reappear under the "Ports (COM & LPT)" section of the Device Manager tree.
My experience is that the device will be reinstalled automatically by Windows. However, it is maybe possible that the complete driver removal will actually have been accomplished by the above instructions, in which case it will be necessary to reinstall the driver. If this happens to you, please let me know and I'll provide instructions for installing the driver.
Once the port has reappeared in Device Manager, start Arduino IDE again and check to see whether the problem still occurs.
There were some previous reports of this "can't set com-state for ..." error occurring specifically when uploading to the boards that use the CH340 USB chip (and apparently only specific batches of those chips). The problem only occurs when using the latest version of the CH340 driver.
The affected users have reported that doing a "roll back" to an older version of the driver was an effective workaround. You can give that a try.
I'll provide instructions:
Open this tutorial from SparkFun in your browser: https://learn.sparkfun.com/tutorials/how-to-install-ch340-drivers/all#drivers-if-you-need-them ⓘ We are using this tutorial as a source for an older version of the CH340 drivers. Generally I recommend only obtaining drivers from the manufacturer of the device, but WCH does not provide older versions of their drivers and SparkFun is trustworthy.
Click the "Windows (EXE)" link you see in red under the "Drivers (If You Need Them)" section of the tutorial.
Wait for the download to finish.
Run the downloaded CH341SER.EXE file.
A "User Account Control" dialog may now appear asking "Do you want to allow this app to make changes to your device?". Click the "Yes" button.
A "DriverSetup(X64)" dialog will appear. Click the "INSTALL" button in the dialog.
Wait for the driver installation to finish, as indicated by the appearance of a "Driver install success!" dialog.
Click the "OK" button in the "Driver install success!" dialog.
Click the X icon at the top right of the "DriverSetup(X64)" dialog to close it.
Close Arduino IDE if it is running.
Connect the Arduino board to your computer with a USB cable.
Select View > Devices by type from the Device Manager menus.
Open the "View" menu.
If there is a ✓ to the left of the "Show hidden devices" menu item, click on "Show hidden devices" to disable it.
Open the "Ports (COM & LPT)" section of the Device Manager tree.
You should see a port identified as "USB-SERIAL CH340 (COM_n_)" under the "Ports (COM & LPT)" section (where "COM_n_" is some serial port e.g., COM4). Right click on that item.
A context menu will open.
Select the "Drivers" tab of the "USB-SERIAL CH340 (COM_n_) Properties" dialog.
You will see a "Roll Back Driver" button in the dialog. If it is not clickable, perform the following instructions:
Select "Update driver" from the context menu.
An "Update Drivers Device - USB-SERIAL CH340 (COM_n_)" dialog will open.
Click on "Search automatically for drivers" in the "Update Drivers Device - USB-SERIAL CH340 (COM_n_)" dialog.
You should now see the driver installation wizard update the driver. Wait for the update to finish, as indicated by the message "Windows has successfully updated your drivers" in the dialog. It is possible you will instead see the message "The best drivers are already installed". If so, please stop following the instructions here and reply on the forum thread to let me know. I'll provide alternative instructions you can follow.
Click the "Close" button in the "Update Drivers Device - USB-SERIAL CH340 (COM_n_)" dialog.
Click the "Roll Back Driver" button in the "USB-SERIAL CH340 (COM_n_) Properties" dialog.
The "Driver Package rollback" dialog will open.
Click the radio button next to "My apps don't work with this driver" in the "Driver Package rollback" dialog .
Click the "Yes" button.
Click the "Close" button in the "USB-SERIAL CH340 (COM_n_) Properties" dialog.
Now start Arduino IDE again and repeat whatever you were doing before when you encountered that error. Please reply here to let us know whether the error still occurs.
Hello sir. i followed these instructions but the error is still the same. the code wont upload. However i should note i am using the older version of the IDE 1.8.18. should i update it to solve the problem?
That should not be necessary. If for some reason you prefer to use Arduino IDE 1.x, that is OK. I would recommend that you update to 1.8.19, since that version contains a fix for a potential security vulnerability present in 1.8.18 (Log4Shell).
I'm going to ask you to post the full verbose output from an upload attempt.
This procedure is not intended to solve the problem. The purpose is to gather more information.
Please do this:
Select File > Preferences... (or Arduino > Preferences... for macOS users) from the Arduino IDE menus.
The "Preferences" dialog will open.
Uncheck the box next to "Show verbose output during: ☑ compilation" in the "Preferences" dialog.
Check the box next to "Show verbose output during: ☐ upload".
Click the "OK" button.
Attempt an upload, as you did before.
After the upload fails, you'll see a button on the right side of the orange bar in Arduino IDE: Copy error messages. Click that button.
This copies the full output to the clipboard.
Open a forum reply here by clicking the "Reply" button.
Click the <CODE/> icon on the post composer toolbar.
This will add the forum's code block markup (```) to your reply to make sure the error messages are correctly formatted.
Press Ctrl+V.
This will paste the error output from the upload into the code block.
Move the cursor outside of the code tags before you add any additional text to your reply.
Sketch uses 3844 bytes (11%) of program storage space. Maximum is 32256 bytes.
Global variables use 758 bytes (37%) of dynamic memory, leaving 1290 bytes for local variables. Maximum is 2048 bytes.
"C:\Users\John\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/bin/avrdude" "-CC:\Users\John\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf" -v -V -patmega328p -carduino "-PCOM3" -b115200 -D "-Uflash:w:C:\Users\John\AppData\Local\Temp\arduino\sketches\B7552C71BBFFD614B386B7FF84D5B956/sketch_nov3a.ino.hex:i"
avrdude: Version 6.3-20190619
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2014 Joerg Wunsch
System wide configuration file is "C:\Users\John\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf"
Using Port : COM3
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: ser_open(): can't set com-state for "\\.\COM3"
avrdude done. Thank you.
Failed uploading: uploading error: exit status 1```
Hi @zephlin4. There were some previous reports of this "can't set com-state for ..." error occurring specifically when uploading to the boards that use the WCH CH340 USB chip (and apparently only specific batches of those chips). The problem only occurs when using the latest version of the CH340 driver.
The affected users have reported that doing a "roll back" to an older version of the driver was an effective workaround. You can give that a try.
I'll provide instructions:
Open this tutorial from SparkFun in your browser: https://learn.sparkfun.com/tutorials/how-to-install-ch340-drivers/all#drivers-if-you-need-them ⓘ We are using this tutorial as a source for an older version of the CH340 drivers. Generally I recommend only obtaining drivers from the manufacturer of the device, but WCH does not provide older versions of their drivers and SparkFun is trustworthy.
Click the "Windows (EXE)" link you see in red under the "Drivers (If You Need Them)" section of the tutorial.
Wait for the download to finish.
Run the downloaded CH341SER.EXE file.
A "User Account Control" dialog may now appear asking "Do you want to allow this app to make changes to your device?". Click the "Yes" button.
A "DriverSetup(X64)" dialog will appear. Click the "INSTALL" button in the dialog.
Wait for the driver installation to finish, as indicated by the appearance of a "Driver install success!" dialog.
Click the "OK" button in the "Driver install success!" dialog.
Click the X icon at the top right of the "DriverSetup(X64)" dialog to close it.
Close Arduino IDE if it is running.
Connect the Arduino board to your computer with a USB cable.
Select View > Devices by type from the Device Manager menus.
Open the "View" menu.
If there is a ✓ to the left of the "Show hidden devices" menu item, click on "Show hidden devices" to disable it.
Open the "Ports (COM & LPT)" section of the Device Manager tree.
You should see a port identified as "USB-SERIAL CH340 (COMn)" under the "Ports (COM & LPT)" section (where "COMn" is some serial port e.g., COM4). Double click on that item.
The "USB-SERIAL CH340 (COMn) Properties" dialog will open.
Select the "Drivers" tab of the "USB-SERIAL CH340 (COMn) Properties" dialog.
You will see a "Roll Back Driver" button in the dialog. If it is not clickable, perform the following instructions:
Click the "Update driver" button.
An "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog will open.
Click on "Search automatically for drivers" in the "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog.
You should now see the driver installation wizard update the driver. Wait for the update to finish, as indicated by the message "Windows has successfully updated your drivers" in the dialog. It is possible you will instead see the message "The best drivers are already installed". If so, please stop following the instructions here and reply on the forum thread to let me know. I'll provide alternative instructions you can follow.
Click the "Close" button in the "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog.
Click the "Roll Back Driver" button in the "USB-SERIAL CH340 (COMn) Properties" dialog.
The "Driver Package rollback" dialog will open.
Click the radio button next to "My apps don't work with this driver" in the "Driver Package rollback" dialog .
Click the "Yes" button.
Click the "Close" button in the "USB-SERIAL CH340 (COMn) Properties" dialog.
Now start Arduino IDE again and repeat whatever you were doing before when you encountered that error before. Hopefully this time you will not encounter that "can't set com-state" error during the sketch upload.
- there is MEGA328P U-TH
- but there i have nothing, just clear chip without any subtitles.
- my arduino
It is possible you will instead see the message "The best drivers are already installed". If so, please stop following the instructions here and reply on the forum thread to let me know. I'll provide alternative instructions you can follow.