Question about virtual com port

[Jyoti Bhayana]

I have a technical issue I am facing while doing development with Nordic NRF52840. I have an application which I am sending command though virtual com port using CDC ACM USB class. When the application is running the COM port shows as Port 30 on my windows. When I switch to my bootloader which also uses virtual com port using CDC ACM USB class, the port changes to 29 . Why the port is not remaining the same in both app and bootloader mode. Is there a way that the port number remains the same when I switch from my application to my bootloader application

In my sdk_config.h file I have same vendor and product ID. // Vendor ID ordered from USB IF: www.usb.org/.../ #ifndef APP_USBD_VID #define APP_USBD_VID 0x1915 #endif

// APP_USBD_PID - Product ID

// Selected Product ID #ifndef APP_USBD_PID #define APP_USBD_PID 0x520F #endif

[Jyoti Bhayana]

I found the issue. The app_usbd_string_config.h was different in both bootloader code and application code . That's the reason the port coming up was different for bootloader and app. After I changed the config file to have the same values for both the bootloader and the app code , they both are showing up as the same port. I have one question for you: Can I write my own bootloader using usb using sdk 13.1. Or there is some restriction that it will not work unless I have sdk 14.x