You can set a unique serial number to the device using the "use serial number string" from USB-Serial Configuration utility. Once the device has a unique serial string it will use the same COM port number.
Can you please let me know if you are using the SuperSpeed Explorer kit?
If yes then the option to access and change the configuration if the Serial Device is not permitted.
Port persist is the case where the com port which corresponds to the device is in use and the device is disconnected from the host. In this case the port will still persist in the device manager even if the device is not connected to the host.
I am not using the SuperSpeed Explorer Kit but rather our own board using the CYUSB3014. Our board exposes two USB CDC devices to the host PC.
The first USB CDC device (e.g. "USB Serial Port (COM15)" in the screen shot above) bridges to an actual UART which communicates to other hardware.
The second USB CDC device (e.g. "USB Serial Port (COM17)" in the screen shot above) accepts user input from the host PC and passes it to the FX3's CPU which prints out debug information.
When I reset the board or unplug/plug the USB cable from the board the COM port names for the devices can change. I want the COM port names to persist.