The wide deployment of the Internet of Things (IoT) brings the challenge to create performing systems with ultra-low power consumption. This paper presents the design of a microcontroller unit (MCU) with a limited set of instructions for IoT applications. This design implemented on FPGA as a proof of concept can gather data from a sensor and broadcast them through a radio transceiver. An estimation of the power consumption in a 65nm CMOS technology leads to a power consumption per instruction cycle around two decades under market components.