Adding USB-C connector to Teensy 4.0 and using external power.

[JoeK]

I'd like a sanity check on this.

My builds usually involve supplying external power and cutting the VUSB pads to continue programming the Teensy over the Micro USB connection.

Now I need to continue doing the same thing power-wise, but I want to add a USB C connection through the enclosure for programming. I'll make an adapter using a Micro USB Male connector and break out the Teensy USB Device lines. The connection between USB C and Micro (2.0) seems pretty straight-forward:

GND, including shell
DP to D+ on the Micro
DN to D-
CC1 and CC2 pulled down with 5.1k resistor.

What to do with VBUS on each connector though? Leave them unconnected? And if so, do I even need to continue cutting the VUSB pad in that case?

Thanks.

 

[JoeK]

Having a look at the Teensy 4.0 schematic, the VBUS line doesn't offer anything to the Teensy if the VUSB pads are cut, so I feel pretty confident it will work if I just leave it unconnected thru my adapter, and then it won't matter if the VUSB pad is cut or not. Could the VBUS line itself be used as one more return path if I connect it all the way thru to the Micro USB Input? Maybe I should just connect it anyway and continue to cut the VUSB pad.