how to force release windows COM port occupied by others process by python code

There is no direct way to force release a COM port occupied by another process using Python code. However, you can try the following approaches:

1. Terminate the process that is currently using the COM port:

You can use the psutil module to get a list of running processes and terminate the one that is using the COM port. Here is an example code:

import psutil

# Get a list of all running processes
processes = psutil.process_iter()

# Loop through the processes to find the one that is using the COM port
for process in processes:
    try:
        connections = process.connections()
        for conn in connections:
            if conn.laddr.port == <COM port number>:
                print(f"Process {process.pid} is using the COM port.")
                process.terminate()
    except:
        pass

Note: This approach is not recommended as it may cause data loss or corruption if the process is terminated abruptly.

2. Use a serial port library that can force release the COM port:

You can use a serial port library like pyserial that has an option to force release the COM port. Here is an example code using pyserial:

import serial.tools.list_ports

# Get a list of all available serial ports
ports = list(serial.tools.list_ports.comports())

# Loop through the ports to find the one that is using the COM port
for port in ports:
    if port.device == <COM port name>:
        print(f"Port {port.device} is using the COM port.")
        ser = serial.Serial(port.device, 9600)
        ser.close()

Note: This approach may not work if the COM port is being used by a kernel-level driver or is locked by the operating system.

3. Use a third-party tool to release the COM port:

You can use a third-party tool like com0com or Portmon to release the COM port. You can call the tool using the subprocess module in Python. Here is an example code using com0com:

import subprocess

# Release the COM port using com0com
subprocess.call(["com0com", "-r", <COM port name>])

Note: This approach requires the installation of the third-party tool and may not work on all operating systems