I have a potential application that would use USB drives to hold some configuration data, and I'm trying to understand the simplest approach to do this. The application requires very little MCU processing power otherwise - any AVR 8 pins and up could handle it, or certainly any ARM Cortex M (these are the families I know best, so it will come down to one of those). The idea is that a user plugs in a pre-configured USB drive and turns an encoder knob or presses a button to select one configuration. That's it.
So I'll need to be able to talk USB and talk files. Beyond that, I'm in unknown territory, but keeping the hardware cheap is important.