Hi, I want to distinguish whether the USB is connected to a PC or a power adapter.
For my application, FATFS still needs to work when connected to a power adapter, so it can not be distinguished via the USB event, as described in https://devzone.nordicsemi.com/f/nordic-q-a/36414/usb.
My idea is that distinguish by the voltage level of D+ and D- when USB is connected. I found a USB register DPDMVALUE relate to the D+ and D-, but I always get a zero value whether connecting to a PC or a power adapter.
My question is how to get the value of DPDMVALUE ? Does it need any other setting? Thanks!