I’m working on a custom board with an STM32F446REt6 and a USB Type-C 2.0 connector (GCT SB4105-GF-A). I haven’t implemented any external pull-up on the D+ and D- lines, but on the CC1 and CC2 pins I have 5.1k pulldown resistors. I managed to load the firmware via DFU and Windows recognizes the device without any issues — the firmware upload works perfectly. However, when I try to use the Virtual COM (CDC), Windows returns an error saying “Unknown USB device (Device descriptor request failed).” I’ve already installed the ST USB drivers but nothing changed. In my .ioc project I enabled USB_OTG_FS, then in middleware I enabled USB_Device and selected Virtual COM. I tried leaving the device descriptor at default and also modifying it, but the issue persists.
Given that DFU works perfectly, I assume the hardware is fine, and the problem is somewhere in the firmware configuration?
I’m attaching the USB schematic section below. Has anyone experienced something similar? Any suggestions on what might be going wrong?
Thanks in advance!
