I've recently been playing with CY7C68013A. Very approachable small USB (high speed!) microcontroller. With tiny amount of code, you can do quite a bit! It does

I've recently been playing with CY7C68013A. Very approachable small USB (high speed!) microcontroller. With tiny amount of code, you can do quite a bit! It doesn't have flash and code is only loaded to SRAM over USB when you connect the controller to the host, so that's pretty flexible. So far I've been practicing on my saleae logic analyzer clone, which is based on this controller too, but there are cheap dev boards orderable from aliexpress, that have this chip which are not limited to input only. Muuuch simpler than STM32, and much faster interface. While some STM32 chips have high speed USB, most cheap boards don't include the high-speed PHY, so it's useless. Can't wait for the dev boards to arrive.