Frequently Asked Questions (and some answers!)¶
I cannot connect to the COM port on Windows¶
If you get errors like:
SerialException: could not open port COM4: [Error 5] Access denied
try disabling and enabling again the COM port from the control panel. Often these errors show a flip-flop behavior: opening a serial port works fine the first time, but not the second. This is because serial ports need to be explicitly closed by programs, otherwise they will remain blocked.
Also, tools like Portmon help with troubleshooting problems with serial ports on Windows.