After full chip erase I don't see virtual COM port on my PC.

[Bartosh]

Hello.

I did a full chip erase using STM32CubeProgrammer and after that I can upload and run the code. Everything works fine like SAI, SPI interfaces but when I try to set communication via USB_FS as a device only to send data to PC using virtual com port I can't see it in a device manager. Before erasing it was working fine. I am using STM32F767ZIT6 on a custop PCB and I programm it using STLink/V2. I tried flashing my code when BOOT0 pin was pulled to 3.3V and to 0V but the result was similar. Do I need to update some firmware that was deleted after full chip erase or the problem is different? 

I included the usbd_cdc_if.h file in my main.c.

Thanks you for help.

PS: I also have a nucleo board with the same mcu and when I programm USB CDC on it everything works just fine.

[STOne-32]

Dear @Bartosh ,

it seems most probably a hardware configuration to be inline with the new code generated . As it is working on the Nucleo , I would suggest to check the “VBus sensing feature” and active it - ado check the schematics around USB pins to your USB connector .

Hope it helps ,

STOne-32