My custom board is a CDC host powered by K20D50M. It has to keep powering/charging external USB CDC device through Vbus all the time but only enumerate it when necessary. Both CDC host and device and based on MQX and K20.
A common practice for starting enumeration is to plug in USB plug to trigger a transition on Vbus, but my case needs to keep Vbus connected consistently.
Question is, is it possible to start the enumeration and USB detachment by only close and open on D+/D- wires by switches?