The NXP MK22DX256VLK5 is a 32-bit ARM Cortex-M4 MCU clocked at 50 MHz, with 256 KB Flash and 32 KB SRAM. That core speed and memory pair handles control-loop and protocol tasks. USB OTG full-speed is built in, so the MCU can act as either host or device — useful for field-update tools, data-logging dongles, or portable instrumentation that connects to a PC for configuration. The 56 GPIOs in an 80-LQFP package give enough headroom for a keypad, a small TFT display, and a handful of sensors without needing an I/O expander.
The 80-LQFP (12x12 mm) is a hand-solderable footprint, which helps during prototyping or small-run production.