The microcontroller is at the heart of every sensor system and is responsible for the control of all the system’s elements, encompassing power management, data sensing, data processing or data transmission. With such a central position, it has a key role in the energy efficiency of the whole system. With that understanding, e-peas propose a general purposes microcontroller, based on a 32-bit ARM architecture and presenting an extremely low power consumption, both in active and standby mode. This is achieved by a combination of a proper technology selection, advanced design techniques, integrated power regulators and an intelligent multimode power management unit that allows fine power tuning.