In this research, the target is to measure the self-consumption of the SAM L21 microcontroller. To accomplish that, it is needed to be familiar with microcontroller functionalities and the way it executes its tasks. A microcontroller (MCU) is compact circuitry integrated on a chip. It has applications in different industries. It is based on a microprocessor in ARM architecture. Besides a microprocessor, there are some more essential components such as memory, bus, I/O peripherals, etc. Microcontrollers can be sorted into a few categories according to architecture, memory type, instruction set, and bit configuration. SAM L21 MCU is built by the Atmel company. It uses the ARM Cortex microprocessor. The main characteristic of that MCU series is low power consumption so it is commonly used in wireless devices and devices with battery supplies. Because of the need for power consumption measurement MCU has several components used in signal acquisition and processing. Power consumption measurement is done with help of the SAM L21 XPLAINED PRO developer kit which has implemented SAM L21 MCU and current measurement header. Microchip Studio software is used to install a specific project on the board. Projects are based on MCU operation in sleep mode and sleepwalking mode. Measurement results are shown in Data Visualizer which is implemented in Microchip Studio. AM L21 microcontroller application in signal acquisiton and processing