Just to add - USB on the F4 can be a bit hit or miss, so I'm not sure if you'll manage to get that working. It might be best sticking with UART.
@Gordon started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Just to add - USB on the F4 can be a bit hit or miss, so I'm not sure if you'll manage to get that working. It might be best sticking with UART.