LAN8742 and USB virtual com port won't coexist?
STM32H735 using the RMII interface to the LAN8742 PHY chip. Right out of the eval board schematic, and it seems to work. USB also implemented in the usual way....and it works, until we turn on the LAN support in X-CUBE-AZRTOS-H7. Then the middleware layer that supports USB_DEVICE goes away. It's grayed-out. Pins are still available.
I haven't seen any references that would suggest these two subsystems can't operate at the same time. We often use the virtual com port for printf debugging purposes, so it's kind of annoying to have the com port disappear. I hotwired a UART output for now to keep the code development moving, but if anyone knows why these two can't both be enabled at the same time, it would be nice to understand it. There must be cases where you need to have both USB and Ethernet present on the same device.
The USB_DEVICE support goes away as soon as we turn on the middleware layer X-CUBE-AZRTOS-H7. That's what the demo board uses for Ethernet support. LWIP leaves USB_DEVICE still available, but we had a lot of trouble with LWIP on a previous project so we'd prefer not to use it. Any suggestions on how we might solve this?