Emulate a USB port as a USB flash drive?

Solution 1:

Unfortunately, USB makes a firm distinction between the Host and the Device. If the USB receptacle on your car has the standard USB A (Host) connector like a PC would have, it means the car's computer wants to be the Host, just like your computer wants to be the Host, so they would most likely conflict with each other and not be able to talk to each other.

Some people have made "USB file transfer cables" for connecting two Hosts together. These cables have an embedded chip that does the work of making the two Hosts appear as devices to each other. I believe these products assume both Hosts are full-fledged PCs, not embedded systems that happen to have a Host connector. I don't have experience with these cables, so I'm not sure whether a software install would be required on one or both ends. It might be worth looking into.

The USB Implementers Forum (the body behind the USB spec) eventually realized the limitations of the Host vs. Device distinction, and created the USB On-The-Go (OTG) specification as a way for USB-capable things to switch between the Host and Device roles on the fly as needed, depending on what they're talking to. However, I think you'd probably need both ends to support USB OTG.