The title is somewhat misleading. Specifically, what I'm trying to do is to connect the SD card inside of my Nintendo 3DS to a USB C port which can be used for charging (so I don't need to keep another charger with me). I figured that because USB C has data anyways, it might reduce some of the wear on the SD card socket and door (it's just two puny plastic tabs keeping it in place!) by putting a reader inside of the DS connected to the data lines on the port.
The trouble is, I doubt it's safe to turn the DS on while it's plugged into a computer (filesystem locking and all that, even if I'm not doing any filesystem operations it will still be mounted by my computer).
My first instinct was to try and put the +5v power for the SD card reader on a NOT gate between the console's power and the port's power. (In other words, if the console is powered on, the reader isn't provided with the power from the USB C port)
Would this NOT gate idea work? I think it should, but I wanted some opinions!
Edit: after reading justme's comment, perhaps I should add an additional gate (or reed switch?) on pin 4 of the SD card as well to isolate the console's power from the reader?