Avrdude: ser_open(): can't set com-state for "\\.\COM3"

kardx · January 10, 2024, 2:10pm

Hello everyone.
So i have an arduino nano(cheap chinese version bought off Amazon) and when i try to upload to it, i just get this error: avrdude: ser_open(): can't set com-state for "\.\COM3".
I'm using Windows 11 and IDE version 1.8.19.
Please tell me how to solve this issue.

ptillisch · January 10, 2024, 2:11pm

Hi @kardx. This "can't set com-state for ..." error occurs when uploading to the boards that use specific batches of the WCH CH340 USB chip. 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:

Click the following link to download the previous version of the driver from the chip manufacturer's website:
https://www.wch-ic.com/downloads/file/65.html?time=2023-03-16%2022:57:59
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.
Open the Windows Device Manager.
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 "Driver" 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:
1. Click the "Update driver" button.
  An "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog will open.
2. Click on "Search automatically for drivers" in the "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog.
3. 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.
4. Click the "Close" button in the "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog.
  The dialog will close.
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.
The "Driver Package rollback" dialog will close.
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.

kardx · January 10, 2024, 2:23pm

Thanks for your instructions. i followed them properly.
Unfortunately, they didn't work. Now the sketch compiles properly (as before) but now it takes a lot of time to upload.
Even after that it doesn't upload properly. Now i get this new error:
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0xad
Thanks again

ptillisch · January 10, 2024, 2:28pm

This is actually progress. When undertaking complex technical endeavors as we often do in our Arduino projects, it is common to end up in a situation where the system has multiple distinct problems. This means that solving one problem only advances you to encountering the next problem in the stack. That makes it difficult to see that any progress is being made, but with enough perseverance you can solve all the problems and finally reach a fully functional state.

You have actually solved the first problem in the "stack". The new error is completely unrelated to the first one. So now we must focus on solving this new problem.

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 IDE > Settings... 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.
Wait for the upload to fail.
You will see a "Upload error: ..." notification at the bottom right corner of the Arduino IDE window. Click the "COPY ERROR MESSAGES" button on that notification.
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 the Ctrl+V keyboard shortcut (Command+V for macOS users).
This will paste the error output from the upload into the code block.
Move the cursor outside of the code block markup before you add any additional text to your reply.
Click the "Reply" button to post the output.

kardx · January 10, 2024, 2:34pm

Arduino: 1.8.19 (Windows 10), Board: "Arduino Nano, ATmega328P"

Sketch uses 924 bytes (3%) of program storage space. Maximum is 30720 bytes.

Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes.

C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avrdude -CC:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf -v -patmega328p -carduino -PCOM3 -b115200 -D -Uflash:w:C:\Users\Preeti\AppData\Local\Temp\arduino_build_630289/Blink.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:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf"



         Using Port                    : COM3

         Using Programmer              : arduino

         Overriding Baud Rate          : 115200

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xa2

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0xa2

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0xa2

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0xa2

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0xa2

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0xa2

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0xa2

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0xa2

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0xa2

avrdude: stk500_recv(): programmer is not responding

avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0xa2



Problem uploading to board.  See https://support.arduino.cc/hc/en-us/sections/360003198300 for suggestions.

avrdude done.  Thank you.

Hi. Here is the output you requested.

ptillisch · January 10, 2024, 3:19pm

A program called a "bootloader" is stored in a special area of memory in the Nano board's microcontroller. The classic Nano (as well as its 3rd party derivatives) have been manufactured with two different types of bootloader installed.

You must configure the Tools > Processor menu in Arduino IDE according to which bootloader is installed on your Nano. Having the incorrect configuration selected in this menu is one of the potential causes of uploads failing with the "avrdude: stk500_recv(): programmer is not responding" error.

The single blink on reset tells us that your Nano board has the "old" bootloader installed.

I can see from the verbose upload output that you have Arduino IDE incorrectly configured for use with the Nano boards that have the modern bootloader.

Select Tools > Processor > ATmega328P (Old Bootloader) from the Arduino IDE menus and then try uploading again.

Hopefully this time the upload will finish successfully.

kardx · January 11, 2024, 6:18am

Thanks for your help, my ide can now upload code to the nano.
Thanks for all suggestions and help given.
Thanks,
Kardx

kardx · January 11, 2024, 6:21am

I just wanted to ask if there is a way to burn the new bootloader. If so i will try to do it.

ptillisch · January 11, 2024, 5:23pm

You are welcome. I'm glad it is working now.

There is. However, the "old bootloader" works perfectly fine for most people. There is a bug in the old bootloader that can cause the board to go into a reset loop if you are using the "watchdog timer":

github.com/arduino/ArduinoCore-avr

ProMini: Reboot loop when using watchdog

opened 07:17AM - 27 Jan 16 UTC

tuxedo0801

bug

Hi there, i have the following problem: I have an arduino sketch which accept …some configuration-details over the serial connection. After applying some configuration, a "reboot" is required. On my leonardo and micro boards, this works quite well by using the watchdog to reset the board: ``` c++ wdt_enable( WDTO_1S ); while(1) {} ``` But with an arduino pro mini at 3,3V/8Mhz the board loops in a restart-loop, forever. It seems that this issue is already known on the net: https://andreasrohner.at/posts/Electronics/How-to-make-the-Watchdog-Timer-work-on-an-Arduino-Pro-Mini-by-replacing-the-bootloader/ I know that there are othr techniques to "reboot" an arduino, but the WDT seems to be the only real hardware reboot, triggered by software. Of course I can use the optiboot bootloader to overcome this issue. But this adds some additional complexity and arduino ide tweaking-skills, which I would like to avoid (there are other people using my sketches/libraries which won't be able to tweak the arduino ide properly). Would it be possible to fix this in arduino ide direclty? For example by switching to optiboot by default or fix the "bug" in the current used bootloader?! br, Alex

If that is something that affects you then it is a good idea to burn the new bootloader. But if you are not affected then it probably isn't worth the effort unless you think it would be a fun project just for the sake of a challenge and a learning experience.

You will need an ISP programmer, which is a piece of hardware that allows your computer to write to the special area of memory where the bootloader is stored. If you don't have access to a dedicated ISP programmer then you can use a spare Arduino board as an "Arduino as ISP" programmer:

kardx · January 14, 2024, 12:10pm

Update-
I had an Arduino Uno with the same issue of this error. After following the steps mentioned above, I found that the IDE could now upload code to the Uno without any issues.

kardx · January 17, 2024, 1:36pm

Update:
My nano throws up the same error, Avrdude: ser_open(): can't set com-state for "\.\COM3. I tried to follow the instructions above again but when i got to doing the driver rollback and updating the driver, it showed that the best drivers are already installed.
please do help!

ptillisch · January 17, 2024, 8:25pm

I have found that when the driver installation gets into this state, it can be solved by uninstalling and then reinstalling the drivers. After that, the "roll back" option should be enabled.

I'll provide instructions:

Close Arduino IDE if it is running.
Connect the Arduino board to your computer with a USB cable.
Open the Windows Device Manager.
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 "Driver" tab of the "USB-SERIAL CH340 (COMn) Properties" dialog.
Click the "Uninstall Device" button.
The "Uninstall Device" dialog will open.
Check the box next to "☐ Attempt to remove the driver for this device.".
Click the "Uninstall" button.
The "Uninstall Device" and "USB-SERIAL CH340 (COMn) Properties" dialogs will close.
Disconnect the USB cable of the Arduino board from your computer.
Reconnect the USB cable of the Arduino board to your computer.
Wait for the "USB-SERIAL CH340 (COMn)" device to appear under the "Ports (COM & LPT)" section of the Device Manager tree.
This will take a couple of minutes as Windows must first automatically reinstall the driver.
It might appear first as a "USB2.0-Serial" device under the "Other devices section of the tree. Just wait for a little longer and it will appear in its final place under the "Ports (COM & LPT)" section.
Click the following link to download the previous version of the driver from the chip manufacturer's website:
https://www.wch-ic.com/downloads/file/65.html?time=2023-03-16%2022:57:59
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.
Switch back to the Windows "Device Manager".
Double click on the "USB-SERIAL CH340 (COMn)" device under the "Ports (COM & LPT)" section.
The "USB-SERIAL CH340 (COMn) Properties" dialog will open.
Select the "Driver" tab of the "USB-SERIAL CH340 (COMn) Properties" dialog.
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.
Click the "Close" button in the "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog.
The dialog will close.
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.
The "Driver Package rollback" dialog will close.
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.

kardx · February 17, 2024, 4:34am

Thank you. My Nano has started working again.

ptillisch · February 17, 2024, 7:41am

You are welcome. I'm glad it is working now.

Regards,
Per

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Avrdude: ser_open(): can't set com-state for "\\.\COM3"

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