The MB89051 series is a general-purpose, single-chip microcontroller that features a compact instruction set and contains a range of peripheral function set and timers, serial interface, a PWM timer, the USB hub function and the USB function. The USB hub function, in particular, supports five down ports (one of them is dedicated to an internal function) allowing them to interface with other USB devices. The microcontrollers also contain one USB function channel to support full speed.