I've seen many posts about connecting a Nano to a Windows 11 machine via USB and having communication issues. I purchased two (2) Nanos directly from Arduino and data cables. I plug in the board and get the USB notification sound and the board blinks then the green light stays on. I compile my code and send it to the board and get the following error code:
Error: programmer is not responding
Warning: attempt 1 of 10: not in sync: resp=0x00
it attempts 10 times.
Error: unable to open port COM3 for programmer arduino
Failed uploading: uploading error: exit status 1
The correct COM port should disappear when you unplug the Nano and reappear when you plug it in again. If that doesn't happen, it's not the correct port.
If the correct driver is not installed, no COM port will appear when you plug in the Nano.
I think I know what you mean by this but please be clear about details like this.
For classic, clone Nano, it's often necessary to select the "atmega328 old bootloader".
You might look in the Windows Device Manager to see where the Nano shows up. In Windows 10, my FTDI adapter shows up as a COM port, and the driver shown for it is an FTDI driver. It should be the same on Windows 11.
This post is under "classic Nano", so when you say that you have purchased a Nano from Arduino, one would reasonably assume in this context that you are referring to the Nano V3 with an ATmega328P MCU onboard. However, official Nano boards from Arduino tend not to have variants of processor types (328PA, 328PB) like one might see with the clone boards. The classic Nano should work with the standard AVR Library by selecting the "Arduino Nano" board option.
On the other hand, there are a number of Arduino Nano products including:
Nano Every
Nano RP2040
Nano ESP32
Nano Connect 33
Nano 33 BLE
All of these are newer boards with processors other than the ATmega328P.
So could we confirm that the Nano boards that you have purchased are definitely the Nano V3 with an ATmega328P processor onboard?
The steady green light indicates that the board is receiving power.
What happened to me just yesterday is, on a nano Atmega328P clone, the USB-C socket became finicky and it is no longer making a good connection and then windows complains that "the last USB device you plugged in malfunctioned.." or something of the sorts. This in turn causes the COM port to malfunction and the "not in sync" messages.
Sometimes windows needs a restart to recover.
But most often I just need to carefully plug in the USB-C
You don't mention which IDE version you're using. The official classic Nano uses the FT232 for communication. And there is an issue (bug) in IDE 2.x related to that if the serial monitor / serial plotter is open.
You can install v1.8 in portable mode so it won't interfere with v2, and you can just delete it later. Download the "Windows ZIP" version, extract it to a folder, and before running it, create a new subfolder named Portable.
