72 MHz Cortex-M3 — enough for USB and control loops
72 MHz core speed handles USB packet processing and real-time control loops. 8 KB RAM holds a USB buffer and a few hundred variables.
USB OTG — no external PHY needed
The USB OTG block supports device, host, and OTG roles. That means you can plug a USB flash drive into the MCU or connect it to a PC for firmware updates — both without an external USB controller. The internal oscillator handles USB timing, so no external crystal is required for full-speed operation.